Ok, scheduler changes this time applied on top of Caglar's fixes.

[linux-2.6.git] / linux-2.6-591-chopstix-intern.patch

diff -Nurb linux-2.6.27-590/arch/Kconfig linux-2.6.27-591/arch/Kconfig
--- linux-2.6.27-590/arch/Kconfig       2010-02-01 19:42:05.000000000 -0500
+++ linux-2.6.27-591/arch/Kconfig       2010-02-01 19:42:30.000000000 -0500
@@ -13,9 +13,18 @@
 
          If unsure, say N.
 
+config CHOPSTIX
+       bool "Chopstix (PlanetLab)"
+       depends on MODULES && OPROFILE
+       help
+         Chopstix allows you to monitor various events by summarizing them
+         in lossy data structures and transferring these data structures
+         into user space. If in doubt, say "N".
+
 config HAVE_OPROFILE
        def_bool n
 
+
 config KPROBES
        bool "Kprobes"
        depends on KALLSYMS && MODULES
diff -Nurb linux-2.6.27-590/arch/x86/kernel/asm-offsets_32.c linux-2.6.27-591/arch/x86/kernel/asm-offsets_32.c
--- linux-2.6.27-590/arch/x86/kernel/asm-offsets_32.c   2008-10-09 18:13:53.000000000 -0400
+++ linux-2.6.27-591/arch/x86/kernel/asm-offsets_32.c   2010-02-01 19:42:30.000000000 -0500
@@ -9,6 +9,7 @@
 #include <linux/signal.h>
 #include <linux/personality.h>
 #include <linux/suspend.h>
+#include <linux/arrays.h>
 #include <linux/kbuild.h>
 #include <asm/ucontext.h>
 #include "sigframe.h"
@@ -24,9 +25,20 @@
 #include <linux/lguest.h>
 #include "../../../drivers/lguest/lg.h"
 
+
+#define STACKOFFSET(sym, str, mem) \
+       DEFINE(sym, offsetof(struct str, mem)-sizeof(struct str));
+
 /* workaround for a warning with -Wmissing-prototypes */
 void foo(void);
 
+struct event_spec {
+       unsigned long pc;
+       unsigned long dcookie;
+       unsigned count;
+       unsigned int number;
+};
+
 void foo(void)
 {
        OFFSET(IA32_SIGCONTEXT_ax, sigcontext, ax);
@@ -50,6 +62,16 @@
        OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
        BLANK();
 
+    STACKOFFSET(TASK_thread, task_struct, thread);
+    STACKOFFSET(THREAD_esp, thread_struct, sp);
+    STACKOFFSET(EVENT_event_data, event, event_data);
+    STACKOFFSET(EVENT_task, event, task);
+    STACKOFFSET(EVENT_event_type, event, event_type);
+    STACKOFFSET(SPEC_number, event_spec, number);
+    DEFINE(EVENT_SIZE, sizeof(struct event));
+    DEFINE(SPEC_SIZE, sizeof(struct event_spec));
+    DEFINE(SPEC_EVENT_SIZE, sizeof(struct event_spec)+sizeof(struct event));
+
        OFFSET(TI_task, thread_info, task);
        OFFSET(TI_exec_domain, thread_info, exec_domain);
        OFFSET(TI_flags, thread_info, flags);
diff -Nurb linux-2.6.27-590/arch/x86/kernel/entry_32.S linux-2.6.27-591/arch/x86/kernel/entry_32.S
--- linux-2.6.27-590/arch/x86/kernel/entry_32.S 2008-10-09 18:13:53.000000000 -0400
+++ linux-2.6.27-591/arch/x86/kernel/entry_32.S 2010-02-01 19:42:30.000000000 -0500
@@ -426,6 +426,33 @@
        cmpl $(nr_syscalls), %eax
        jae syscall_badsys
 syscall_call:
+    /* Move Chopstix syscall probe here */
+    /* Save and clobber: eax, ecx, ebp  */
+    pushl   %eax
+    pushl   %ecx
+    pushl   %ebp
+    movl    %esp, %ebp
+    subl    $SPEC_EVENT_SIZE, %esp 
+    movl    rec_event, %ecx
+    testl   %ecx, %ecx
+    jz  carry_on
+    # struct event is first, just below %ebp
+    movl    %eax, (SPEC_number-EVENT_SIZE)(%ebp)
+    leal    -SPEC_EVENT_SIZE(%ebp), %eax
+    movl    %eax, EVENT_event_data(%ebp)
+    movl    $6, EVENT_event_type(%ebp)
+    movl    rec_event, %edx
+    movl    $1, 4(%esp)
+    leal    -EVENT_SIZE(%ebp), %eax
+    movl    %eax, (%esp)
+    call    rec_event_asm 
+carry_on: 
+    addl $SPEC_EVENT_SIZE, %esp
+    popl %ebp
+    popl %ecx
+    popl %eax
+     /* End chopstix */
+
        call *sys_call_table(,%eax,4)
        movl %eax,PT_EAX(%esp)          # store the return value
 syscall_exit:
diff -Nurb linux-2.6.27-590/arch/x86/mm/fault.c linux-2.6.27-591/arch/x86/mm/fault.c
--- linux-2.6.27-590/arch/x86/mm/fault.c        2010-02-01 19:42:05.000000000 -0500
+++ linux-2.6.27-591/arch/x86/mm/fault.c        2010-02-01 19:42:30.000000000 -0500
@@ -79,6 +79,15 @@
 #endif
 }
 
+
+extern void (*rec_event)(void *,unsigned int);
+struct event_spec {
+       unsigned long pc;
+       unsigned long dcookie; 
+       unsigned count;
+       unsigned char reason;
+};
+
 /*
  * X86_32
  * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
diff -Nurb linux-2.6.27-590/drivers/oprofile/cpu_buffer.c linux-2.6.27-591/drivers/oprofile/cpu_buffer.c
--- linux-2.6.27-590/drivers/oprofile/cpu_buffer.c      2008-10-09 18:13:53.000000000 -0400
+++ linux-2.6.27-591/drivers/oprofile/cpu_buffer.c      2010-02-01 19:42:30.000000000 -0500
@@ -21,6 +21,7 @@
 #include <linux/oprofile.h>
 #include <linux/vmalloc.h>
 #include <linux/errno.h>
+#include <linux/arrays.h>
  
 #include "event_buffer.h"
 #include "cpu_buffer.h"
@@ -147,6 +148,17 @@
                b->head_pos = 0;
 }
 
+#ifdef CONFIG_CHOPSTIX
+
+struct event_spec {
+       unsigned int pc;
+       unsigned long dcookie;
+       unsigned count;
+};
+
+extern void (*rec_event)(void *,unsigned int);
+#endif
+
 static inline void
 add_sample(struct oprofile_cpu_buffer * cpu_buf,
            unsigned long pc, unsigned long event)
@@ -155,6 +167,7 @@
        entry->eip = pc;
        entry->event = event;
        increment_head(cpu_buf);
+
 }
 
 static inline void
@@ -250,8 +263,28 @@
 {
        int is_kernel = !user_mode(regs);
        unsigned long pc = profile_pc(regs);
+       int res=0;
 
+#ifdef CONFIG_CHOPSTIX
+       if (rec_event) {
+               struct event esig;
+               struct event_spec espec;
+               esig.task = current;
+               espec.pc=pc;
+               espec.count=1;
+               esig.event_data=&espec;
+               esig.event_type=event; /* index in the event array currently set up */
+                                       /* make sure the counters are loaded in the order we want them to show up*/ 
+               (*rec_event)(&esig, 1);
+       }
+       else {
        oprofile_add_ext_sample(pc, regs, event, is_kernel);
+       }
+#else
+       oprofile_add_ext_sample(pc, regs, event, is_kernel);
+#endif
+
+
 }
 
 void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
diff -Nurb linux-2.6.27-590/fs/bio.c linux-2.6.27-591/fs/bio.c
--- linux-2.6.27-590/fs/bio.c   2008-10-09 18:13:53.000000000 -0400
+++ linux-2.6.27-591/fs/bio.c   2010-02-01 19:42:30.000000000 -0500
@@ -27,6 +27,7 @@
 #include <linux/workqueue.h>
 #include <linux/blktrace_api.h>
 #include <scsi/sg.h>           /* for struct sg_iovec */
+#include <linux/arrays.h>
 
 static struct kmem_cache *bio_slab __read_mostly;
 
@@ -44,6 +45,7 @@
 };
 #undef BV
 
+
 /*
  * fs_bio_set is the bio_set containing bio and iovec memory pools used by
  * IO code that does not need private memory pools.
@@ -1171,6 +1173,14 @@
        }
 }
 
+struct event_spec {
+       unsigned long pc;
+       unsigned long dcookie;
+       unsigned count;
+       unsigned char reason;
+};
+
+extern void (*rec_event)(void *,unsigned int);
 /**
  * bio_endio - end I/O on a bio
  * @bio:       bio
@@ -1192,6 +1202,24 @@
        else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
                error = -EIO;
 
+#if 0
+               if (rec_event) {
+                       struct event event;
+                       struct event_spec espec;
+                       unsigned long eip;
+                       
+                       espec.reason = 1;/*response */
+
+                       eip = bio->bi_end_io;
+                       event.event_data=&espec;
+                       espec.pc=eip;
+                       event.event_type=3; 
+                       /* index in the event array currently set up */
+                       /* make sure the counters are loaded in the order we want them to show up*/ 
+                       (*rec_event)(&event, bytes_done);
+               }
+#endif
+
        if (bio->bi_end_io)
                bio->bi_end_io(bio, error);
 }
diff -Nurb linux-2.6.27-590/fs/exec.c linux-2.6.27-591/fs/exec.c
--- linux-2.6.27-590/fs/exec.c  2010-02-01 19:42:07.000000000 -0500
+++ linux-2.6.27-591/fs/exec.c  2010-02-01 19:42:31.000000000 -0500
@@ -27,6 +27,7 @@
 #include <linux/fdtable.h>
 #include <linux/mm.h>
 #include <linux/stat.h>
+#include <linux/dcookies.h>
 #include <linux/fcntl.h>
 #include <linux/smp_lock.h>
 #include <linux/swap.h>
@@ -698,6 +699,13 @@
                goto out;
        }
 
+ #ifdef CONFIG_CHOPSTIX
+    unsigned long cookie;
+    extern void (*rec_event)(void *, unsigned int);
+    if (rec_event && !nd.path.dentry->d_cookie)
+        get_dcookie(&nd.path, &cookie);
+ #endif
+
        return file;
 
  out_path_put:
diff -Nurb linux-2.6.27-590/include/linux/arrays.h linux-2.6.27-591/include/linux/arrays.h
--- linux-2.6.27-590/include/linux/arrays.h     1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.27-591/include/linux/arrays.h     2010-02-01 19:42:31.000000000 -0500
@@ -0,0 +1,36 @@
+#ifndef __ARRAYS_H__
+#define __ARRAYS_H__
+#include <linux/list.h>
+
+#define SAMPLING_METHOD_DEFAULT 0
+#define SAMPLING_METHOD_LOG 1
+
+/* Every probe has an array handler */
+
+/* XXX - Optimize this structure */
+
+extern void (*rec_event)(void *,unsigned int);
+struct array_handler {
+       struct list_head link;
+       unsigned int (*hash_func)(void *);
+       unsigned int (*sampling_func)(void *,int,void *);
+       unsigned short size;
+       unsigned int threshold;
+       unsigned char **expcount;
+       unsigned int sampling_method;
+       unsigned int **arrays;
+       unsigned int arraysize;
+       unsigned int num_samples[2];
+       void **epoch_samples; /* size-sized lists of samples */
+       unsigned int (*serialize)(void *, void *);
+       unsigned char code[5];
+};
+
+struct event {
+       struct list_head link;
+       void *event_data;
+       unsigned int count;
+       unsigned int event_type;
+       struct task_struct *task;
+};
+#endif
diff -Nurb linux-2.6.27-590/include/linux/sched.h linux-2.6.27-591/include/linux/sched.h
--- linux-2.6.27-590/include/linux/sched.h      2010-02-01 19:42:07.000000000 -0500
+++ linux-2.6.27-591/include/linux/sched.h      2010-02-01 19:47:30.000000000 -0500
@@ -1133,6 +1133,11 @@
        cputime_t utime, stime, utimescaled, stimescaled;
        cputime_t gtime;
        cputime_t prev_utime, prev_stime;
+
+    #ifdef CONFIG_CHOPSTIX
+            unsigned long last_interrupted, last_ran_j;
+    #endif
+
        unsigned long nvcsw, nivcsw; /* context switch counts */
        struct timespec start_time;             /* monotonic time */
        struct timespec real_start_time;        /* boot based time */
diff -Nurb linux-2.6.27-590/include/linux/sched.h.rej linux-2.6.27-591/include/linux/sched.h.rej
--- linux-2.6.27-590/include/linux/sched.h.rej  1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.27-591/include/linux/sched.h.rej  2010-02-01 19:42:31.000000000 -0500
@@ -0,0 +1,19 @@
+***************
+*** 850,855 ****
+  #endif
+       unsigned long sleep_avg;
+       unsigned long long timestamp, last_ran;
+       unsigned long long sched_time; /* sched_clock time spent running */
+       enum sleep_type sleep_type;
+  
+--- 850,859 ----
+  #endif
+       unsigned long sleep_avg;
+       unsigned long long timestamp, last_ran;
++ #ifdef CONFIG_CHOPSTIX
++      unsigned long last_interrupted, last_ran_j;
++ #endif
++ 
+       unsigned long long sched_time; /* sched_clock time spent running */
+       enum sleep_type sleep_type;
+  
diff -Nurb linux-2.6.27-590/kernel/sched.c linux-2.6.27-591/kernel/sched.c
--- linux-2.6.27-590/kernel/sched.c     2010-02-01 19:42:07.000000000 -0500
+++ linux-2.6.27-591/kernel/sched.c     2010-02-01 19:47:30.000000000 -0500
@@ -10,7 +10,7 @@
  *  1998-11-19 Implemented schedule_timeout() and related stuff
  *             by Andrea Arcangeli
  *  2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
- *             hybrid priority-list and round-robin design with
+ *             hybrid priority-list and round-robin deventn with
  *             an array-switch method of distributing timeslices
  *             and per-CPU runqueues.  Cleanups and useful suggestions
  *             by Davide Libenzi, preemptible kernel bits by Robert Love.
@@ -73,12 +73,16 @@
 #include <linux/ftrace.h>
 #include <linux/vs_sched.h>
 #include <linux/vs_cvirt.h>
+#include <linux/arrays.h>
 
 #include <asm/tlb.h>
 #include <asm/irq_regs.h>
 
 #include "sched_cpupri.h"
 
+#define INTERRUPTIBLE   -1
+#define RUNNING         0
+
 /*
  * Convert user-nice values [ -20 ... 0 ... 19 ]
  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
@@ -2368,6 +2372,10 @@
        INIT_HLIST_HEAD(&p->preempt_notifiers);
 #endif
 
+#ifdef CONFIG_CHOPSTIX
+    p->last_ran_j = jiffies;
+    p->last_interrupted = INTERRUPTIBLE;
+#endif
        /*
         * We mark the process as running here, but have not actually
         * inserted it onto the runqueue yet. This guarantees that
@@ -4428,6 +4436,29 @@
        }
 }
 
+void (*rec_event)(void *,unsigned int) = NULL;
+EXPORT_SYMBOL(rec_event);
+#ifdef CONFIG_CHOPSTIX
+
+struct event_spec {
+    unsigned long pc;
+    unsigned long dcookie;
+    unsigned int count;
+    unsigned int reason;
+};
+
+/* To support safe calling from asm */
+asmlinkage void rec_event_asm (struct event *event_signature_in, unsigned int count) {
+    struct pt_regs *regs;
+    struct event_spec *es = event_signature_in->event_data;
+    regs = task_pt_regs(current);
+    event_signature_in->task=current;
+    es->pc=regs->ip;
+    event_signature_in->count=1;
+    (*rec_event)(event_signature_in, count);
+}
+#endif
+
 /*
  * schedule() is the main scheduler function.
  */
@@ -4482,6 +4513,61 @@
        next = pick_next_task(rq, prev);
 
        if (likely(prev != next)) {
+
+#ifdef CONFIG_CHOPSTIX
+       /* Run only if the Chopstix module so decrees it */
+       if (rec_event) {
+        unsigned long diff;
+        int sampling_reason;
+               prev->last_ran_j = jiffies;
+               if (next->last_interrupted!=INTERRUPTIBLE) {
+                       if (next->last_interrupted!=RUNNING) {
+                               diff = (jiffies-next->last_interrupted);
+                               sampling_reason = 0;/* BLOCKING */
+                       }
+                       else {
+                               diff = jiffies-next->last_ran_j; 
+                               sampling_reason = 1;/* PREEMPTION */
+                       }
+
+                       if (diff >= HZ/10) {
+                struct event_spec {
+                   unsigned long pc;
+                   unsigned long dcookie;
+                   unsigned int count;
+                   unsigned int reason;
+                };
+
+                               struct event event;
+                               struct event_spec espec;
+                struct pt_regs *regs;
+                regs = task_pt_regs(current);
+
+                               espec.reason = sampling_reason;
+                               event.event_data=&espec;
+                               event.task=next;
+                               espec.pc=regs->ip;
+                               event.event_type=2; 
+                               /* index in the event array currently set up */
+                               /* make sure the counters are loaded in the order we want them to show up*/ 
+                               (*rec_event)(&event, diff);
+                       }
+               }
+        /* next has been elected to run */
+               next->last_interrupted=0;
+
+        /* An uninterruptible process just yielded. Record the current jiffy */
+        if (prev->state & TASK_UNINTERRUPTIBLE) {
+            prev->last_interrupted=jiffies;
+        }
+         /* An interruptible process just yielded, or it got preempted. 
+          * Mark it as interruptible */
+        else if (prev->state & TASK_INTERRUPTIBLE) {
+            prev->last_interrupted=INTERRUPTIBLE;
+        }
+       }
+#endif
+
                sched_info_switch(prev, next);
 
                rq->nr_switches++;
@@ -5369,6 +5455,7 @@
        get_task_struct(p);
        read_unlock(&tasklist_lock);
 
+
        retval = -EPERM;
        if ((current->euid != p->euid) && (current->euid != p->uid) &&
                        !capable(CAP_SYS_NICE))
diff -Nurb linux-2.6.27-590/kernel/sched.c.orig linux-2.6.27-591/kernel/sched.c.orig
--- linux-2.6.27-590/kernel/sched.c.orig        1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.27-591/kernel/sched.c.orig        2010-02-01 19:43:07.000000000 -0500
@@ -0,0 +1,9326 @@
+/*
+ *  kernel/sched.c
+ *
+ *  Kernel scheduler and related syscalls
+ *
+ *  Copyright (C) 1991-2002  Linus Torvalds
+ *
+ *  1996-12-23  Modified by Dave Grothe to fix bugs in semaphores and
+ *             make semaphores SMP safe
+ *  1998-11-19 Implemented schedule_timeout() and related stuff
+ *             by Andrea Arcangeli
+ *  2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
+ *             hybrid priority-list and round-robin deventn with
+ *             an array-switch method of distributing timeslices
+ *             and per-CPU runqueues.  Cleanups and useful suggestions
+ *             by Davide Libenzi, preemptible kernel bits by Robert Love.
+ *  2003-09-03 Interactivity tuning by Con Kolivas.
+ *  2004-04-02 Scheduler domains code by Nick Piggin
+ *  2007-04-15  Work begun on replacing all interactivity tuning with a
+ *              fair scheduling design by Con Kolivas.
+ *  2007-05-05  Load balancing (smp-nice) and other improvements
+ *              by Peter Williams
+ *  2007-05-06  Interactivity improvements to CFS by Mike Galbraith
+ *  2007-07-01  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  2007-11-29  RT balancing improvements by Steven Rostedt, Gregory Haskins,
+ *              Thomas Gleixner, Mike Kravetz
+ */
+
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/highmem.h>
+#include <linux/smp_lock.h>
+#include <asm/mmu_context.h>
+#include <linux/interrupt.h>
+#include <linux/capability.h>
+#include <linux/completion.h>
+#include <linux/kernel_stat.h>
+#include <linux/debug_locks.h>
+#include <linux/security.h>
+#include <linux/notifier.h>
+#include <linux/profile.h>
+#include <linux/freezer.h>
+#include <linux/vmalloc.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/pid_namespace.h>
+#include <linux/smp.h>
+#include <linux/threads.h>
+#include <linux/timer.h>
+#include <linux/rcupdate.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/percpu.h>
+#include <linux/kthread.h>
+#include <linux/seq_file.h>
+#include <linux/sysctl.h>
+#include <linux/syscalls.h>
+#include <linux/times.h>
+#include <linux/tsacct_kern.h>
+#include <linux/kprobes.h>
+#include <linux/delayacct.h>
+#include <linux/reciprocal_div.h>
+#include <linux/unistd.h>
+#include <linux/pagemap.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/bootmem.h>
+#include <linux/debugfs.h>
+#include <linux/ctype.h>
+#include <linux/ftrace.h>
+#include <linux/vs_sched.h>
+#include <linux/vs_cvirt.h>
+#include <linux/arrays.h>
+
+#include <asm/tlb.h>
+#include <asm/irq_regs.h>
+
+#include "sched_cpupri.h"
+
+#define INTERRUPTIBLE   -1
+#define RUNNING         0
+
+/*
+ * Convert user-nice values [ -20 ... 0 ... 19 ]
+ * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
+ * and back.
+ */
+#define NICE_TO_PRIO(nice)     (MAX_RT_PRIO + (nice) + 20)
+#define PRIO_TO_NICE(prio)     ((prio) - MAX_RT_PRIO - 20)
+#define TASK_NICE(p)           PRIO_TO_NICE((p)->static_prio)
+
+/*
+ * 'User priority' is the nice value converted to something we
+ * can work with better when scaling various scheduler parameters,
+ * it's a [ 0 ... 39 ] range.
+ */
+#define USER_PRIO(p)           ((p)-MAX_RT_PRIO)
+#define TASK_USER_PRIO(p)      USER_PRIO((p)->static_prio)
+#define MAX_USER_PRIO          (USER_PRIO(MAX_PRIO))
+
+/*
+ * Helpers for converting nanosecond timing to jiffy resolution
+ */
+#define NS_TO_JIFFIES(TIME)    ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+
+#define NICE_0_LOAD            SCHED_LOAD_SCALE
+#define NICE_0_SHIFT           SCHED_LOAD_SHIFT
+
+/*
+ * These are the 'tuning knobs' of the scheduler:
+ *
+ * default timeslice is 100 msecs (used only for SCHED_RR tasks).
+ * Timeslices get refilled after they expire.
+ */
+#define DEF_TIMESLICE          (100 * HZ / 1000)
+
+/*
+ * single value that denotes runtime == period, ie unlimited time.
+ */
+#define RUNTIME_INF    ((u64)~0ULL)
+
+#ifdef CONFIG_SMP
+/*
+ * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
+ * Since cpu_power is a 'constant', we can use a reciprocal divide.
+ */
+static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
+{
+       return reciprocal_divide(load, sg->reciprocal_cpu_power);
+}
+
+/*
+ * Each time a sched group cpu_power is changed,
+ * we must compute its reciprocal value
+ */
+static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
+{
+       sg->__cpu_power += val;
+       sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
+}
+#endif
+
+static inline int rt_policy(int policy)
+{
+       if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
+               return 1;
+       return 0;
+}
+
+static inline int task_has_rt_policy(struct task_struct *p)
+{
+       return rt_policy(p->policy);
+}
+
+/*
+ * This is the priority-queue data structure of the RT scheduling class:
+ */
+struct rt_prio_array {
+       DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
+       struct list_head queue[MAX_RT_PRIO];
+};
+
+struct rt_bandwidth {
+       /* nests inside the rq lock: */
+       spinlock_t              rt_runtime_lock;
+       ktime_t                 rt_period;
+       u64                     rt_runtime;
+       struct hrtimer          rt_period_timer;
+};
+
+static struct rt_bandwidth def_rt_bandwidth;
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
+
+static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
+{
+       struct rt_bandwidth *rt_b =
+               container_of(timer, struct rt_bandwidth, rt_period_timer);
+       ktime_t now;
+       int overrun;
+       int idle = 0;
+
+       for (;;) {
+               now = hrtimer_cb_get_time(timer);
+               overrun = hrtimer_forward(timer, now, rt_b->rt_period);
+
+               if (!overrun)
+                       break;
+
+               idle = do_sched_rt_period_timer(rt_b, overrun);
+       }
+
+       return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+static
+void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
+{
+       rt_b->rt_period = ns_to_ktime(period);
+       rt_b->rt_runtime = runtime;
+
+       spin_lock_init(&rt_b->rt_runtime_lock);
+
+       hrtimer_init(&rt_b->rt_period_timer,
+                       CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       rt_b->rt_period_timer.function = sched_rt_period_timer;
+       rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
+}
+
+static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+       ktime_t now;
+
+       if (rt_b->rt_runtime == RUNTIME_INF)
+               return;
+
+       if (hrtimer_active(&rt_b->rt_period_timer))
+               return;
+
+       spin_lock(&rt_b->rt_runtime_lock);
+       for (;;) {
+               if (hrtimer_active(&rt_b->rt_period_timer))
+                       break;
+
+               now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
+               hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
+               hrtimer_start(&rt_b->rt_period_timer,
+                             rt_b->rt_period_timer.expires,
+                             HRTIMER_MODE_ABS);
+       }
+       spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+       hrtimer_cancel(&rt_b->rt_period_timer);
+}
+#endif
+
+/*
+ * sched_domains_mutex serializes calls to arch_init_sched_domains,
+ * detach_destroy_domains and partition_sched_domains.
+ */
+static DEFINE_MUTEX(sched_domains_mutex);
+
+#ifdef CONFIG_GROUP_SCHED
+
+#include <linux/cgroup.h>
+
+struct cfs_rq;
+
+static LIST_HEAD(task_groups);
+
+/* task group related information */
+struct task_group {
+#ifdef CONFIG_CGROUP_SCHED
+       struct cgroup_subsys_state css;
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       /* schedulable entities of this group on each cpu */
+       struct sched_entity **se;
+       /* runqueue "owned" by this group on each cpu */
+       struct cfs_rq **cfs_rq;
+       unsigned long shares;
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+       struct sched_rt_entity **rt_se;
+       struct rt_rq **rt_rq;
+
+       struct rt_bandwidth rt_bandwidth;
+#endif
+
+       struct rcu_head rcu;
+       struct list_head list;
+
+       struct task_group *parent;
+       struct list_head siblings;
+       struct list_head children;
+};
+
+#ifdef CONFIG_USER_SCHED
+
+/*
+ * Root task group.
+ *     Every UID task group (including init_task_group aka UID-0) will
+ *     be a child to this group.
+ */
+struct task_group root_task_group;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/* Default task group's sched entity on each cpu */
+static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
+/* Default task group's cfs_rq on each cpu */
+static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
+static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
+#endif /* CONFIG_RT_GROUP_SCHED */
+#else /* !CONFIG_FAIR_GROUP_SCHED */
+#define root_task_group init_task_group
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+/* task_group_lock serializes add/remove of task groups and also changes to
+ * a task group's cpu shares.
+ */
+static DEFINE_SPINLOCK(task_group_lock);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_USER_SCHED
+# define INIT_TASK_GROUP_LOAD  (2*NICE_0_LOAD)
+#else /* !CONFIG_USER_SCHED */
+# define INIT_TASK_GROUP_LOAD  NICE_0_LOAD
+#endif /* CONFIG_USER_SCHED */
+
+/*
+ * A weight of 0 or 1 can cause arithmetics problems.
+ * A weight of a cfs_rq is the sum of weights of which entities
+ * are queued on this cfs_rq, so a weight of a entity should not be
+ * too large, so as the shares value of a task group.
+ * (The default weight is 1024 - so there's no practical
+ *  limitation from this.)
+ */
+#define MIN_SHARES     2
+#define MAX_SHARES     (1UL << 18)
+
+static int init_task_group_load = INIT_TASK_GROUP_LOAD;
+#endif
+
+/* Default task group.
+ *     Every task in system belong to this group at bootup.
+ */
+struct task_group init_task_group;
+
+/* return group to which a task belongs */
+static inline struct task_group *task_group(struct task_struct *p)
+{
+       struct task_group *tg;
+
+#ifdef CONFIG_USER_SCHED
+       tg = p->user->tg;
+#elif defined(CONFIG_CGROUP_SCHED)
+       tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
+                               struct task_group, css);
+#else
+       tg = &init_task_group;
+#endif
+       return tg;
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
+       p->se.parent = task_group(p)->se[cpu];
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+       p->rt.rt_rq  = task_group(p)->rt_rq[cpu];
+       p->rt.parent = task_group(p)->rt_se[cpu];
+#endif
+}
+
+#else
+
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
+static inline struct task_group *task_group(struct task_struct *p)
+{
+       return NULL;
+}
+
+#endif /* CONFIG_GROUP_SCHED */
+
+/* CFS-related fields in a runqueue */
+struct cfs_rq {
+       struct load_weight load;
+       unsigned long nr_running;
+
+       u64 exec_clock;
+       u64 min_vruntime;
+       u64 pair_start;
+
+       struct rb_root tasks_timeline;
+       struct rb_node *rb_leftmost;
+
+       struct list_head tasks;
+       struct list_head *balance_iterator;
+
+       /*
+        * 'curr' points to currently running entity on this cfs_rq.
+        * It is set to NULL otherwise (i.e when none are currently running).
+        */
+       struct sched_entity *curr, *next;
+
+       unsigned long nr_spread_over;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */
+
+       /*
+        * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
+        * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
+        * (like users, containers etc.)
+        *
+        * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
+        * list is used during load balance.
+        */
+       struct list_head leaf_cfs_rq_list;
+       struct task_group *tg;  /* group that "owns" this runqueue */
+
+#ifdef CONFIG_SMP
+       /*
+        * the part of load.weight contributed by tasks
+        */
+       unsigned long task_weight;
+
+       /*
+        *   h_load = weight * f(tg)
+        *
+        * Where f(tg) is the recursive weight fraction assigned to
+        * this group.
+        */
+       unsigned long h_load;
+
+       /*
+        * this cpu's part of tg->shares
+        */
+       unsigned long shares;
+
+       /*
+        * load.weight at the time we set shares
+        */
+       unsigned long rq_weight;
+#endif
+#endif
+};
+
+/* Real-Time classes' related field in a runqueue: */
+struct rt_rq {
+       struct rt_prio_array active;
+       unsigned long rt_nr_running;
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+       int highest_prio; /* highest queued rt task prio */
+#endif
+#ifdef CONFIG_SMP
+       unsigned long rt_nr_migratory;
+       int overloaded;
+#endif
+       int rt_throttled;
+       u64 rt_time;
+       u64 rt_runtime;
+       /* Nests inside the rq lock: */
+       spinlock_t rt_runtime_lock;
+
+#ifdef CONFIG_RT_GROUP_SCHED
+       unsigned long rt_nr_boosted;
+
+       struct rq *rq;
+       struct list_head leaf_rt_rq_list;
+       struct task_group *tg;
+       struct sched_rt_entity *rt_se;
+#endif
+};
+
+#ifdef CONFIG_SMP
+
+/*
+ * We add the notion of a root-domain which will be used to define per-domain
+ * variables. Each exclusive cpuset essentially defines an island domain by
+ * fully partitioning the member cpus from any other cpuset. Whenever a new
+ * exclusive cpuset is created, we also create and attach a new root-domain
+ * object.
+ *
+ */
+struct root_domain {
+       atomic_t refcount;
+       cpumask_t span;
+       cpumask_t online;
+
+       /*
+        * The "RT overload" flag: it gets set if a CPU has more than
+        * one runnable RT task.
+        */
+       cpumask_t rto_mask;
+       atomic_t rto_count;
+#ifdef CONFIG_SMP
+       struct cpupri cpupri;
+#endif
+};
+
+/*
+ * By default the system creates a single root-domain with all cpus as
+ * members (mimicking the global state we have today).
+ */
+static struct root_domain def_root_domain;
+
+#endif
+       unsigned long norm_time;
+       unsigned long idle_time;
+#ifdef CONFIG_VSERVER_IDLETIME
+       int idle_skip;
+#endif
+#ifdef CONFIG_VSERVER_HARDCPU
+       struct list_head hold_queue;
+       unsigned long nr_onhold;
+       int idle_tokens;
+#endif
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ *
+ * Locking rule: those places that want to lock multiple runqueues
+ * (such as the load balancing or the thread migration code), lock
+ * acquire operations must be ordered by ascending &runqueue.
+ */
+struct rq {
+       /* runqueue lock: */
+       spinlock_t lock;
+
+       /*
+        * nr_running and cpu_load should be in the same cacheline because
+        * remote CPUs use both these fields when doing load calculation.
+        */
+       unsigned long nr_running;
+       #define CPU_LOAD_IDX_MAX 5
+       unsigned long cpu_load[CPU_LOAD_IDX_MAX];
+       unsigned char idle_at_tick;
+#ifdef CONFIG_NO_HZ
+       unsigned long last_tick_seen;
+       unsigned char in_nohz_recently;
+#endif
+       /* capture load from *all* tasks on this cpu: */
+       struct load_weight load;
+       unsigned long nr_load_updates;
+       u64 nr_switches;
+
+       struct cfs_rq cfs;
+       struct rt_rq rt;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       /* list of leaf cfs_rq on this cpu: */
+       struct list_head leaf_cfs_rq_list;
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+       struct list_head leaf_rt_rq_list;
+#endif
+
+       /*
+        * This is part of a global counter where only the total sum
+        * over all CPUs matters. A task can increase this counter on
+        * one CPU and if it got migrated afterwards it may decrease
+        * it on another CPU. Always updated under the runqueue lock:
+        */
+       unsigned long nr_uninterruptible;
+
+       struct task_struct *curr, *idle;
+       unsigned long next_balance;
+       struct mm_struct *prev_mm;
+
+       u64 clock;
+
+       atomic_t nr_iowait;
+
+#ifdef CONFIG_SMP
+       struct root_domain *rd;
+       struct sched_domain *sd;
+
+       /* For active balancing */
+       int active_balance;
+       int push_cpu;
+       /* cpu of this runqueue: */
+       int cpu;
+       int online;
+
+       unsigned long avg_load_per_task;
+
+       struct task_struct *migration_thread;
+       struct list_head migration_queue;
+#endif
+
+#ifdef CONFIG_SCHED_HRTICK
+#ifdef CONFIG_SMP
+       int hrtick_csd_pending;
+       struct call_single_data hrtick_csd;
+#endif
+       struct hrtimer hrtick_timer;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+       /* latency stats */
+       struct sched_info rq_sched_info;
+
+       /* sys_sched_yield() stats */
+       unsigned int yld_exp_empty;
+       unsigned int yld_act_empty;
+       unsigned int yld_both_empty;
+       unsigned int yld_count;
+
+       /* schedule() stats */
+       unsigned int sched_switch;
+       unsigned int sched_count;
+       unsigned int sched_goidle;
+
+       /* try_to_wake_up() stats */
+       unsigned int ttwu_count;
+       unsigned int ttwu_local;
+
+       /* BKL stats */
+       unsigned int bkl_count;
+#endif
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
+{
+       rq->curr->sched_class->check_preempt_curr(rq, p);
+}
+
+static inline int cpu_of(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+       return rq->cpu;
+#else
+       return 0;
+#endif
+}
+
+/*
+ * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
+ * See detach_destroy_domains: synchronize_sched for details.
+ *
+ * The domain tree of any CPU may only be accessed from within
+ * preempt-disabled sections.
+ */
+#define for_each_domain(cpu, __sd) \
+       for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
+
+#define cpu_rq(cpu)            (&per_cpu(runqueues, (cpu)))
+#define this_rq()              (&__get_cpu_var(runqueues))
+#define task_rq(p)             cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)          (cpu_rq(cpu)->curr)
+
+static inline void update_rq_clock(struct rq *rq)
+{
+       rq->clock = sched_clock_cpu(cpu_of(rq));
+}
+
+/*
+ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
+ */
+#ifdef CONFIG_SCHED_DEBUG
+# define const_debug __read_mostly
+#else
+# define const_debug static const
+#endif
+
+/**
+ * runqueue_is_locked
+ *
+ * Returns true if the current cpu runqueue is locked.
+ * This interface allows printk to be called with the runqueue lock
+ * held and know whether or not it is OK to wake up the klogd.
+ */
+int runqueue_is_locked(void)
+{
+       int cpu = get_cpu();
+       struct rq *rq = cpu_rq(cpu);
+       int ret;
+
+       ret = spin_is_locked(&rq->lock);
+       put_cpu();
+       return ret;
+}
+
+/*
+ * Debugging: various feature bits
+ */
+
+#define SCHED_FEAT(name, enabled)      \
+       __SCHED_FEAT_##name ,
+
+enum {
+#include "sched_features.h"
+};
+
+#undef SCHED_FEAT
+
+#define SCHED_FEAT(name, enabled)      \
+       (1UL << __SCHED_FEAT_##name) * enabled |
+
+const_debug unsigned int sysctl_sched_features =
+#include "sched_features.h"
+       0;
+
+#undef SCHED_FEAT
+
+#ifdef CONFIG_SCHED_DEBUG
+#define SCHED_FEAT(name, enabled)      \
+       #name ,
+
+static __read_mostly char *sched_feat_names[] = {
+#include "sched_features.h"
+       NULL
+};
+
+#undef SCHED_FEAT
+
+static int sched_feat_open(struct inode *inode, struct file *filp)
+{
+       filp->private_data = inode->i_private;
+       return 0;
+}
+
+static ssize_t
+sched_feat_read(struct file *filp, char __user *ubuf,
+               size_t cnt, loff_t *ppos)
+{
+       char *buf;
+       int r = 0;
+       int len = 0;
+       int i;
+
+       for (i = 0; sched_feat_names[i]; i++) {
+               len += strlen(sched_feat_names[i]);
+               len += 4;
+       }
+
+       buf = kmalloc(len + 2, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       for (i = 0; sched_feat_names[i]; i++) {
+               if (sysctl_sched_features & (1UL << i))
+                       r += sprintf(buf + r, "%s ", sched_feat_names[i]);
+               else
+                       r += sprintf(buf + r, "NO_%s ", sched_feat_names[i]);
+       }
+
+       r += sprintf(buf + r, "\n");
+       WARN_ON(r >= len + 2);
+
+       r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+
+       kfree(buf);
+
+       return r;
+}
+
+static ssize_t
+sched_feat_write(struct file *filp, const char __user *ubuf,
+               size_t cnt, loff_t *ppos)
+{
+       char buf[64];
+       char *cmp = buf;
+       int neg = 0;
+       int i;
+
+       if (cnt > 63)
+               cnt = 63;
+
+       if (copy_from_user(&buf, ubuf, cnt))
+               return -EFAULT;
+
+       buf[cnt] = 0;
+
+       if (strncmp(buf, "NO_", 3) == 0) {
+               neg = 1;
+               cmp += 3;
+       }
+
+       for (i = 0; sched_feat_names[i]; i++) {
+               int len = strlen(sched_feat_names[i]);
+
+               if (strncmp(cmp, sched_feat_names[i], len) == 0) {
+                       if (neg)
+                               sysctl_sched_features &= ~(1UL << i);
+                       else
+                               sysctl_sched_features |= (1UL << i);
+                       break;
+               }
+       }
+
+       if (!sched_feat_names[i])
+               return -EINVAL;
+
+       filp->f_pos += cnt;
+
+       return cnt;
+}
+
+static struct file_operations sched_feat_fops = {
+       .open   = sched_feat_open,
+       .read   = sched_feat_read,
+       .write  = sched_feat_write,
+};
+
+static __init int sched_init_debug(void)
+{
+       debugfs_create_file("sched_features", 0644, NULL, NULL,
+                       &sched_feat_fops);
+
+       return 0;
+}
+late_initcall(sched_init_debug);
+
+#endif
+
+#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+/*
+ * Number of tasks to iterate in a single balance run.
+ * Limited because this is done with IRQs disabled.
+ */
+const_debug unsigned int sysctl_sched_nr_migrate = 32;
+
+/*
+ * ratelimit for updating the group shares.
+ * default: 0.25ms
+ */
+unsigned int sysctl_sched_shares_ratelimit = 250000;
+
+/*
+ * period over which we measure -rt task cpu usage in us.
+ * default: 1s
+ */
+unsigned int sysctl_sched_rt_period = 1000000;
+
+static __read_mostly int scheduler_running;
+
+/*
+ * part of the period that we allow rt tasks to run in us.
+ * default: 0.95s
+ */
+int sysctl_sched_rt_runtime = 950000;
+
+static inline u64 global_rt_period(void)
+{
+       return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
+}
+
+static inline u64 global_rt_runtime(void)
+{
+       if (sysctl_sched_rt_runtime < 0)
+               return RUNTIME_INF;
+
+       return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
+}
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)     do { } while (0)
+#endif
+#ifndef finish_arch_switch
+# define finish_arch_switch(prev)      do { } while (0)
+#endif
+
+static inline int task_current(struct rq *rq, struct task_struct *p)
+{
+       return rq->curr == p;
+}
+
+#ifndef __ARCH_WANT_UNLOCKED_CTXSW
+static inline int task_running(struct rq *rq, struct task_struct *p)
+{
+       return task_current(rq, p);
+}
+
+static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
+{
+}
+
+static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+       /* this is a valid case when another task releases the spinlock */
+       rq->lock.owner = current;
+#endif
+       /*
+        * If we are tracking spinlock dependencies then we have to
+        * fix up the runqueue lock - which gets 'carried over' from
+        * prev into current:
+        */
+       spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
+
+       spin_unlock_irq(&rq->lock);
+}
+
+#else /* __ARCH_WANT_UNLOCKED_CTXSW */
+static inline int task_running(struct rq *rq, struct task_struct *p)
+{
+#ifdef CONFIG_SMP
+       return p->oncpu;
+#else
+       return task_current(rq, p);
+#endif
+}
+
+static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
+{
+#ifdef CONFIG_SMP
+       /*
+        * We can optimise this out completely for !SMP, because the
+        * SMP rebalancing from interrupt is the only thing that cares
+        * here.
+        */
+       next->oncpu = 1;
+#endif
+#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
+       spin_unlock_irq(&rq->lock);
+#else
+       spin_unlock(&rq->lock);
+#endif
+}
+
+static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
+{
+#ifdef CONFIG_SMP
+       /*
+        * After ->oncpu is cleared, the task can be moved to a different CPU.
+        * We must ensure this doesn't happen until the switch is completely
+        * finished.
+        */
+       smp_wmb();
+       prev->oncpu = 0;
+#endif
+#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
+       local_irq_enable();
+#endif
+}
+#endif /* __ARCH_WANT_UNLOCKED_CTXSW */
+
+/*
+ * __task_rq_lock - lock the runqueue a given task resides on.
+ * Must be called interrupts disabled.
+ */
+static inline struct rq *__task_rq_lock(struct task_struct *p)
+       __acquires(rq->lock)
+{
+       for (;;) {
+               struct rq *rq = task_rq(p);
+               spin_lock(&rq->lock);
+               if (likely(rq == task_rq(p)))
+                       return rq;
+               spin_unlock(&rq->lock);
+       }
+}
+
+/*
+ * task_rq_lock - lock the runqueue a given task resides on and disable
+ * interrupts. Note the ordering: we can safely lookup the task_rq without
+ * explicitly disabling preemption.
+ */
+static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
+       __acquires(rq->lock)
+{
+       struct rq *rq;
+
+       for (;;) {
+               local_irq_save(*flags);
+               rq = task_rq(p);
+               spin_lock(&rq->lock);
+               if (likely(rq == task_rq(p)))
+                       return rq;
+               spin_unlock_irqrestore(&rq->lock, *flags);
+       }
+}
+
+static void __task_rq_unlock(struct rq *rq)
+       __releases(rq->lock)
+{
+       spin_unlock(&rq->lock);
+}
+
+static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
+       __releases(rq->lock)
+{
+       spin_unlock_irqrestore(&rq->lock, *flags);
+}
+
+/*
+ * this_rq_lock - lock this runqueue and disable interrupts.
+ */
+static struct rq *this_rq_lock(void)
+       __acquires(rq->lock)
+{
+       struct rq *rq;
+
+       local_irq_disable();
+       rq = this_rq();
+       spin_lock(&rq->lock);
+
+       return rq;
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+/*
+ * Use HR-timers to deliver accurate preemption points.
+ *
+ * Its all a bit involved since we cannot program an hrt while holding the
+ * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
+ * reschedule event.
+ *
+ * When we get rescheduled we reprogram the hrtick_timer outside of the
+ * rq->lock.
+ */
+
+/*
+ * Use hrtick when:
+ *  - enabled by features
+ *  - hrtimer is actually high res
+ */
+static inline int hrtick_enabled(struct rq *rq)
+{
+       if (!sched_feat(HRTICK))
+               return 0;
+       if (!cpu_active(cpu_of(rq)))
+               return 0;
+       return hrtimer_is_hres_active(&rq->hrtick_timer);
+}
+
+static void hrtick_clear(struct rq *rq)
+{
+       if (hrtimer_active(&rq->hrtick_timer))
+               hrtimer_cancel(&rq->hrtick_timer);
+}
+
+/*
+ * High-resolution timer tick.
+ * Runs from hardirq context with interrupts disabled.
+ */
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
+{
+       struct rq *rq = container_of(timer, struct rq, hrtick_timer);
+
+       WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+
+       spin_lock(&rq->lock);
+       update_rq_clock(rq);
+       rq->curr->sched_class->task_tick(rq, rq->curr, 1);
+       spin_unlock(&rq->lock);
+
+       return HRTIMER_NORESTART;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
+{
+       struct rq *rq = arg;
+
+       spin_lock(&rq->lock);
+       hrtimer_restart(&rq->hrtick_timer);
+       rq->hrtick_csd_pending = 0;
+       spin_unlock(&rq->lock);
+}
+
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
+{
+       struct hrtimer *timer = &rq->hrtick_timer;
+       ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
+
+       timer->expires = time;
+
+       if (rq == this_rq()) {
+               hrtimer_restart(timer);
+       } else if (!rq->hrtick_csd_pending) {
+               __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
+               rq->hrtick_csd_pending = 1;
+       }
+}
+
+static int
+hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+       int cpu = (int)(long)hcpu;
+
+       switch (action) {
+       case CPU_UP_CANCELED:
+       case CPU_UP_CANCELED_FROZEN:
+       case CPU_DOWN_PREPARE:
+       case CPU_DOWN_PREPARE_FROZEN:
+       case CPU_DEAD:
+       case CPU_DEAD_FROZEN:
+               hrtick_clear(cpu_rq(cpu));
+               return NOTIFY_OK;
+       }
+
+       return NOTIFY_DONE;
+}
+
+static __init void init_hrtick(void)
+{
+       hotcpu_notifier(hotplug_hrtick, 0);
+}
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
+{
+       hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
+}
+
+static void init_hrtick(void)
+{
+}
+#endif /* CONFIG_SMP */
+
+static void init_rq_hrtick(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+       rq->hrtick_csd_pending = 0;
+
+       rq->hrtick_csd.flags = 0;
+       rq->hrtick_csd.func = __hrtick_start;
+       rq->hrtick_csd.info = rq;
+#endif
+
+       hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       rq->hrtick_timer.function = hrtick;
+       rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
+}
+#else
+static inline void hrtick_clear(struct rq *rq)
+{
+}
+
+static inline void init_rq_hrtick(struct rq *rq)
+{
+}
+
+static inline void init_hrtick(void)
+{
+}
+#endif
+
+/*
+ * resched_task - mark a task 'to be rescheduled now'.
+ *
+ * On UP this means the setting of the need_resched flag, on SMP it
+ * might also involve a cross-CPU call to trigger the scheduler on
+ * the target CPU.
+ */
+#ifdef CONFIG_SMP
+
+#ifndef tsk_is_polling
+#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
+#endif
+
+static void resched_task(struct task_struct *p)
+{
+       int cpu;
+
+       assert_spin_locked(&task_rq(p)->lock);
+
+       if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+               return;
+
+       set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+
+       cpu = task_cpu(p);
+       if (cpu == smp_processor_id())
+               return;
+
+       /* NEED_RESCHED must be visible before we test polling */
+       smp_mb();
+       if (!tsk_is_polling(p))
+               smp_send_reschedule(cpu);
+}
+
+static void resched_cpu(int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long flags;
+
+       if (!spin_trylock_irqsave(&rq->lock, flags))
+               return;
+       resched_task(cpu_curr(cpu));
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+#ifdef CONFIG_NO_HZ
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+void wake_up_idle_cpu(int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+
+       if (cpu == smp_processor_id())
+               return;
+
+       /*
+        * This is safe, as this function is called with the timer
+        * wheel base lock of (cpu) held. When the CPU is on the way
+        * to idle and has not yet set rq->curr to idle then it will
+        * be serialized on the timer wheel base lock and take the new
+        * timer into account automatically.
+        */
+       if (rq->curr != rq->idle)
+               return;
+
+       /*
+        * We can set TIF_RESCHED on the idle task of the other CPU
+        * lockless. The worst case is that the other CPU runs the
+        * idle task through an additional NOOP schedule()
+        */
+       set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
+
+       /* NEED_RESCHED must be visible before we test polling */
+       smp_mb();
+       if (!tsk_is_polling(rq->idle))
+               smp_send_reschedule(cpu);
+}
+#endif /* CONFIG_NO_HZ */
+
+#else /* !CONFIG_SMP */
+static void resched_task(struct task_struct *p)
+{
+       assert_spin_locked(&task_rq(p)->lock);
+       set_tsk_need_resched(p);
+}
+#endif /* CONFIG_SMP */
+
+#if BITS_PER_LONG == 32
+# define WMULT_CONST   (~0UL)
+#else
+# define WMULT_CONST   (1UL << 32)
+#endif
+
+#define WMULT_SHIFT    32
+
+/*
+ * Shift right and round:
+ */
+#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
+
+/*
+ * delta *= weight / lw
+ */
+static unsigned long
+calc_delta_mine(unsigned long delta_exec, unsigned long weight,
+               struct load_weight *lw)
+{
+       u64 tmp;
+
+       if (!lw->inv_weight) {
+               if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
+                       lw->inv_weight = 1;
+               else
+                       lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
+                               / (lw->weight+1);
+       }
+
+       tmp = (u64)delta_exec * weight;
+       /*
+        * Check whether we'd overflow the 64-bit multiplication:
+        */
+       if (unlikely(tmp > WMULT_CONST))
+               tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
+                       WMULT_SHIFT/2);
+       else
+               tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
+
+       return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
+}
+
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
+{
+       lw->weight += inc;
+       lw->inv_weight = 0;
+}
+
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
+{
+       lw->weight -= dec;
+       lw->inv_weight = 0;
+}
+
+/*
+ * To aid in avoiding the subversion of "niceness" due to uneven distribution
+ * of tasks with abnormal "nice" values across CPUs the contribution that
+ * each task makes to its run queue's load is weighted according to its
+ * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
+ * scaled version of the new time slice allocation that they receive on time
+ * slice expiry etc.
+ */
+
+#define WEIGHT_IDLEPRIO                2
+#define WMULT_IDLEPRIO         (1 << 31)
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+static const int prio_to_weight[40] = {
+ /* -20 */     88761,     71755,     56483,     46273,     36291,
+ /* -15 */     29154,     23254,     18705,     14949,     11916,
+ /* -10 */      9548,      7620,      6100,      4904,      3906,
+ /*  -5 */      3121,      2501,      1991,      1586,      1277,
+ /*   0 */      1024,       820,       655,       526,       423,
+ /*   5 */       335,       272,       215,       172,       137,
+ /*  10 */       110,        87,        70,        56,        45,
+ /*  15 */        36,        29,        23,        18,        15,
+};
+
+/*
+ * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+static const u32 prio_to_wmult[40] = {
+ /* -20 */     48388,     59856,     76040,     92818,    118348,
+ /* -15 */    147320,    184698,    229616,    287308,    360437,
+ /* -10 */    449829,    563644,    704093,    875809,   1099582,
+ /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
+ /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
+ /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
+ /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
+ /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
+
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
+
+/*
+ * runqueue iterator, to support SMP load-balancing between different
+ * scheduling classes, without having to expose their internal data
+ * structures to the load-balancing proper:
+ */
+struct rq_iterator {
+       void *arg;
+       struct task_struct *(*start)(void *);
+       struct task_struct *(*next)(void *);
+};
+
+#ifdef CONFIG_SMP
+static unsigned long
+balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+             unsigned long max_load_move, struct sched_domain *sd,
+             enum cpu_idle_type idle, int *all_pinned,
+             int *this_best_prio, struct rq_iterator *iterator);
+
+static int
+iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+                  struct sched_domain *sd, enum cpu_idle_type idle,
+                  struct rq_iterator *iterator);
+#endif
+
+#ifdef CONFIG_CGROUP_CPUACCT
+static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
+#else
+static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
+#endif
+
+static inline void inc_cpu_load(struct rq *rq, unsigned long load)
+{
+       update_load_add(&rq->load, load);
+}
+
+static inline void dec_cpu_load(struct rq *rq, unsigned long load)
+{
+       update_load_sub(&rq->load, load);
+}
+
+#ifdef CONFIG_SMP
+static unsigned long source_load(int cpu, int type);
+static unsigned long target_load(int cpu, int type);
+static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
+
+static unsigned long cpu_avg_load_per_task(int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+
+       if (rq->nr_running)
+               rq->avg_load_per_task = rq->load.weight / rq->nr_running;
+
+       return rq->avg_load_per_task;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *);
+
+/*
+ * Iterate the full tree, calling @down when first entering a node and @up when
+ * leaving it for the final time.
+ */
+static void
+walk_tg_tree(tg_visitor down, tg_visitor up, int cpu, struct sched_domain *sd)
+{
+       struct task_group *parent, *child;
+
+       rcu_read_lock();
+       parent = &root_task_group;
+down:
+       (*down)(parent, cpu, sd);
+       list_for_each_entry_rcu(child, &parent->children, siblings) {
+               parent = child;
+               goto down;
+
+up:
+               continue;
+       }
+       (*up)(parent, cpu, sd);
+
+       child = parent;
+       parent = parent->parent;
+       if (parent)
+               goto up;
+       rcu_read_unlock();
+}
+
+static void __set_se_shares(struct sched_entity *se, unsigned long shares);
+
+/*
+ * Calculate and set the cpu's group shares.
+ */
+static void
+__update_group_shares_cpu(struct task_group *tg, int cpu,
+                         unsigned long sd_shares, unsigned long sd_rq_weight)
+{
+       int boost = 0;
+       unsigned long shares;
+       unsigned long rq_weight;
+
+       if (!tg->se[cpu])
+               return;
+
+       rq_weight = tg->cfs_rq[cpu]->load.weight;
+
+       /*
+        * If there are currently no tasks on the cpu pretend there is one of
+        * average load so that when a new task gets to run here it will not
+        * get delayed by group starvation.
+        */
+       if (!rq_weight) {
+               boost = 1;
+               rq_weight = NICE_0_LOAD;
+       }
+
+       if (unlikely(rq_weight > sd_rq_weight))
+               rq_weight = sd_rq_weight;
+
+       /*
+        *           \Sum shares * rq_weight
+        * shares =  -----------------------
+        *               \Sum rq_weight
+        *
+        */
+       shares = (sd_shares * rq_weight) / (sd_rq_weight + 1);
+
+       /*
+        * record the actual number of shares, not the boosted amount.
+        */
+       tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
+       tg->cfs_rq[cpu]->rq_weight = rq_weight;
+
+       if (shares < MIN_SHARES)
+               shares = MIN_SHARES;
+       else if (shares > MAX_SHARES)
+               shares = MAX_SHARES;
+
+       __set_se_shares(tg->se[cpu], shares);
+}
+
+/*
+ * Re-compute the task group their per cpu shares over the given domain.
+ * This needs to be done in a bottom-up fashion because the rq weight of a
+ * parent group depends on the shares of its child groups.
+ */
+static void
+tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd)
+{
+       unsigned long rq_weight = 0;
+       unsigned long shares = 0;
+       int i;
+
+       for_each_cpu_mask(i, sd->span) {
+               rq_weight += tg->cfs_rq[i]->load.weight;
+               shares += tg->cfs_rq[i]->shares;
+       }
+
+       if ((!shares && rq_weight) || shares > tg->shares)
+               shares = tg->shares;
+
+       if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
+               shares = tg->shares;
+
+       if (!rq_weight)
+               rq_weight = cpus_weight(sd->span) * NICE_0_LOAD;
+
+       for_each_cpu_mask(i, sd->span) {
+               struct rq *rq = cpu_rq(i);
+               unsigned long flags;
+
+               spin_lock_irqsave(&rq->lock, flags);
+               __update_group_shares_cpu(tg, i, shares, rq_weight);
+               spin_unlock_irqrestore(&rq->lock, flags);
+       }
+}
+
+/*
+ * Compute the cpu's hierarchical load factor for each task group.
+ * This needs to be done in a top-down fashion because the load of a child
+ * group is a fraction of its parents load.
+ */
+static void
+tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd)
+{
+       unsigned long load;
+
+       if (!tg->parent) {
+               load = cpu_rq(cpu)->load.weight;
+       } else {
+               load = tg->parent->cfs_rq[cpu]->h_load;
+               load *= tg->cfs_rq[cpu]->shares;
+               load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
+       }
+
+       tg->cfs_rq[cpu]->h_load = load;
+}
+
+static void
+tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd)
+{
+}
+
+static void update_shares(struct sched_domain *sd)
+{
+       u64 now = cpu_clock(raw_smp_processor_id());
+       s64 elapsed = now - sd->last_update;
+
+       if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
+               sd->last_update = now;
+               walk_tg_tree(tg_nop, tg_shares_up, 0, sd);
+       }
+}
+
+static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
+{
+       spin_unlock(&rq->lock);
+       update_shares(sd);
+       spin_lock(&rq->lock);
+}
+
+static void update_h_load(int cpu)
+{
+       walk_tg_tree(tg_load_down, tg_nop, cpu, NULL);
+}
+
+#else
+
+static inline void update_shares(struct sched_domain *sd)
+{
+}
+
+static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
+{
+}
+
+#endif
+
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
+{
+#ifdef CONFIG_SMP
+       cfs_rq->shares = shares;
+#endif
+}
+#endif
+
+#include "sched_stats.h"
+#include "sched_idletask.c"
+#include "sched_fair.c"
+#include "sched_rt.c"
+#ifdef CONFIG_SCHED_DEBUG
+# include "sched_debug.c"
+#endif
+
+#define sched_class_highest (&rt_sched_class)
+#define for_each_class(class) \
+   for (class = sched_class_highest; class; class = class->next)
+
+static void inc_nr_running(struct rq *rq)
+{
+       rq->nr_running++;
+}
+
+static void dec_nr_running(struct rq *rq)
+{
+       rq->nr_running--;
+}
+
+static void set_load_weight(struct task_struct *p)
+{
+       if (task_has_rt_policy(p)) {
+               p->se.load.weight = prio_to_weight[0] * 2;
+               p->se.load.inv_weight = prio_to_wmult[0] >> 1;
+               return;
+       }
+
+       /*
+        * SCHED_IDLE tasks get minimal weight:
+        */
+       if (p->policy == SCHED_IDLE) {
+               p->se.load.weight = WEIGHT_IDLEPRIO;
+               p->se.load.inv_weight = WMULT_IDLEPRIO;
+               return;
+       }
+
+       p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
+       p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
+}
+
+static void update_avg(u64 *avg, u64 sample)
+{
+       s64 diff = sample - *avg;
+       *avg += diff >> 3;
+}
+
+static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
+{
+       // BUG_ON(p->state & TASK_ONHOLD);
+       sched_info_queued(p);
+       p->sched_class->enqueue_task(rq, p, wakeup);
+       p->se.on_rq = 1;
+}
+
+static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
+{
+       if (sleep && p->se.last_wakeup) {
+               update_avg(&p->se.avg_overlap,
+                          p->se.sum_exec_runtime - p->se.last_wakeup);
+               p->se.last_wakeup = 0;
+       }
+
+       sched_info_dequeued(p);
+       p->sched_class->dequeue_task(rq, p, sleep);
+       p->se.on_rq = 0;
+}
+
+/*
+ * __normal_prio - return the priority that is based on the static prio
+ */
+static inline int __normal_prio(struct task_struct *p)
+{
+       return p->static_prio;
+}
+
+/*
+ * Calculate the expected normal priority: i.e. priority
+ * without taking RT-inheritance into account. Might be
+ * boosted by interactivity modifiers. Changes upon fork,
+ * setprio syscalls, and whenever the interactivity
+ * estimator recalculates.
+ */
+static inline int normal_prio(struct task_struct *p)
+{
+       int prio;
+
+       if (task_has_rt_policy(p))
+               prio = MAX_RT_PRIO-1 - p->rt_priority;
+       else
+               prio = __normal_prio(p);
+       return prio;
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks, or might be boosted by
+ * interactivity modifiers. Will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(struct task_struct *p)
+{
+       p->normal_prio = normal_prio(p);
+       /*
+        * If we are RT tasks or we were boosted to RT priority,
+        * keep the priority unchanged. Otherwise, update priority
+        * to the normal priority:
+        */
+       if (!rt_prio(p->prio))
+               return p->normal_prio;
+       return p->prio;
+}
+
+/*
+ * activate_task - move a task to the runqueue.
+ */
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
+{
+       if (task_contributes_to_load(p))
+               rq->nr_uninterruptible--;
+
+       enqueue_task(rq, p, wakeup);
+       inc_nr_running(rq);
+}
+
+/*
+ * deactivate_task - remove a task from the runqueue.
+ */
+static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
+{
+       if (task_contributes_to_load(p))
+               rq->nr_uninterruptible++;
+
+       dequeue_task(rq, p, sleep);
+       dec_nr_running(rq);
+}
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ */
+inline int task_curr(const struct task_struct *p)
+{
+       return cpu_curr(task_cpu(p)) == p;
+}
+
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+       set_task_rq(p, cpu);
+#ifdef CONFIG_SMP
+       /*
+        * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
+        * successfuly executed on another CPU. We must ensure that updates of
+        * per-task data have been completed by this moment.
+        */
+       smp_wmb();
+       task_thread_info(p)->cpu = cpu;
+#endif
+}
+
+static inline void check_class_changed(struct rq *rq, struct task_struct *p,
+                                      const struct sched_class *prev_class,
+                                      int oldprio, int running)
+{
+       if (prev_class != p->sched_class) {
+               if (prev_class->switched_from)
+                       prev_class->switched_from(rq, p, running);
+               p->sched_class->switched_to(rq, p, running);
+       } else
+               p->sched_class->prio_changed(rq, p, oldprio, running);
+}
+
+#ifdef CONFIG_SMP
+
+/* Used instead of source_load when we know the type == 0 */
+static unsigned long weighted_cpuload(const int cpu)
+{
+       return cpu_rq(cpu)->load.weight;
+}
+
+/*
+ * Is this task likely cache-hot:
+ */
+static int
+task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
+{
+       s64 delta;
+
+       /*
+        * Buddy candidates are cache hot:
+        */
+       if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next))
+               return 1;
+
+       if (p->sched_class != &fair_sched_class)
+               return 0;
+
+       if (sysctl_sched_migration_cost == -1)
+               return 1;
+       if (sysctl_sched_migration_cost == 0)
+               return 0;
+
+       delta = now - p->se.exec_start;
+
+       return delta < (s64)sysctl_sched_migration_cost;
+}
+
+
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+{
+       int old_cpu = task_cpu(p);
+       struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
+       struct cfs_rq *old_cfsrq = task_cfs_rq(p),
+                     *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
+       u64 clock_offset;
+
+       clock_offset = old_rq->clock - new_rq->clock;
+
+#ifdef CONFIG_SCHEDSTATS
+       if (p->se.wait_start)
+               p->se.wait_start -= clock_offset;
+       if (p->se.sleep_start)
+               p->se.sleep_start -= clock_offset;
+       if (p->se.block_start)
+               p->se.block_start -= clock_offset;
+       if (old_cpu != new_cpu) {
+               schedstat_inc(p, se.nr_migrations);
+               if (task_hot(p, old_rq->clock, NULL))
+                       schedstat_inc(p, se.nr_forced2_migrations);
+       }
+#endif
+       p->se.vruntime -= old_cfsrq->min_vruntime -
+                                        new_cfsrq->min_vruntime;
+
+       __set_task_cpu(p, new_cpu);
+}
+
+struct migration_req {
+       struct list_head list;
+
+       struct task_struct *task;
+       int dest_cpu;
+
+       struct completion done;
+};
+
+#include "sched_mon.h"
+
+
+/*
+ * The task's runqueue lock must be held.
+ * Returns true if you have to wait for migration thread.
+ */
+static int
+migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
+{
+       struct rq *rq = task_rq(p);
+
+       vxm_migrate_task(p, rq, dest_cpu);
+       /*
+        * If the task is not on a runqueue (and not running), then
+        * it is sufficient to simply update the task's cpu field.
+        */
+       if (!p->se.on_rq && !task_running(rq, p)) {
+               set_task_cpu(p, dest_cpu);
+               return 0;
+       }
+
+       init_completion(&req->done);
+       req->task = p;
+       req->dest_cpu = dest_cpu;
+       list_add(&req->list, &rq->migration_queue);
+
+       return 1;
+}
+
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * If @match_state is nonzero, it's the @p->state value just checked and
+ * not expected to change.  If it changes, i.e. @p might have woken up,
+ * then return zero.  When we succeed in waiting for @p to be off its CPU,
+ * we return a positive number (its total switch count).  If a second call
+ * a short while later returns the same number, the caller can be sure that
+ * @p has remained unscheduled the whole time.
+ *
+ * The caller must ensure that the task *will* unschedule sometime soon,
+ * else this function might spin for a *long* time. This function can't
+ * be called with interrupts off, or it may introduce deadlock with
+ * smp_call_function() if an IPI is sent by the same process we are
+ * waiting to become inactive.
+ */
+unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+{
+       unsigned long flags;
+       int running, on_rq;
+       unsigned long ncsw;
+       struct rq *rq;
+
+       for (;;) {
+               /*
+                * We do the initial early heuristics without holding
+                * any task-queue locks at all. We'll only try to get
+                * the runqueue lock when things look like they will
+                * work out!
+                */
+               rq = task_rq(p);
+
+               /*
+                * If the task is actively running on another CPU
+                * still, just relax and busy-wait without holding
+                * any locks.
+                *
+                * NOTE! Since we don't hold any locks, it's not
+                * even sure that "rq" stays as the right runqueue!
+                * But we don't care, since "task_running()" will
+                * return false if the runqueue has changed and p
+                * is actually now running somewhere else!
+                */
+               while (task_running(rq, p)) {
+                       if (match_state && unlikely(p->state != match_state))
+                               return 0;
+                       cpu_relax();
+               }
+
+               /*
+                * Ok, time to look more closely! We need the rq
+                * lock now, to be *sure*. If we're wrong, we'll
+                * just go back and repeat.
+                */
+               rq = task_rq_lock(p, &flags);
+               running = task_running(rq, p);
+               on_rq = p->se.on_rq;
+               ncsw = 0;
+               if (!match_state || p->state == match_state) {
+                       ncsw = p->nivcsw + p->nvcsw;
+                       if (unlikely(!ncsw))
+                               ncsw = 1;
+               }
+               task_rq_unlock(rq, &flags);
+
+               /*
+                * If it changed from the expected state, bail out now.
+                */
+               if (unlikely(!ncsw))
+                       break;
+
+               /*
+                * Was it really running after all now that we
+                * checked with the proper locks actually held?
+                *
+                * Oops. Go back and try again..
+                */
+               if (unlikely(running)) {
+                       cpu_relax();
+                       continue;
+               }
+
+               /*
+                * It's not enough that it's not actively running,
+                * it must be off the runqueue _entirely_, and not
+                * preempted!
+                *
+                * So if it wa still runnable (but just not actively
+                * running right now), it's preempted, and we should
+                * yield - it could be a while.
+                */
+               if (unlikely(on_rq)) {
+                       schedule_timeout_uninterruptible(1);
+                       continue;
+               }
+
+               /*
+                * Ahh, all good. It wasn't running, and it wasn't
+                * runnable, which means that it will never become
+                * running in the future either. We're all done!
+                */
+               break;
+       }
+
+       return ncsw;
+}
+
+/***
+ * kick_process - kick a running thread to enter/exit the kernel
+ * @p: the to-be-kicked thread
+ *
+ * Cause a process which is running on another CPU to enter
+ * kernel-mode, without any delay. (to get signals handled.)
+ *
+ * NOTE: this function doesnt have to take the runqueue lock,
+ * because all it wants to ensure is that the remote task enters
+ * the kernel. If the IPI races and the task has been migrated
+ * to another CPU then no harm is done and the purpose has been
+ * achieved as well.
+ */
+void kick_process(struct task_struct *p)
+{
+       int cpu;
+
+       preempt_disable();
+       cpu = task_cpu(p);
+       if ((cpu != smp_processor_id()) && task_curr(p))
+               smp_send_reschedule(cpu);
+       preempt_enable();
+}
+
+/*
+ * Return a low guess at the load of a migration-source cpu weighted
+ * according to the scheduling class and "nice" value.
+ *
+ * We want to under-estimate the load of migration sources, to
+ * balance conservatively.
+ */
+static unsigned long source_load(int cpu, int type)
+{
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long total = weighted_cpuload(cpu);
+
+       if (type == 0 || !sched_feat(LB_BIAS))
+               return total;
+
+       return min(rq->cpu_load[type-1], total);
+}
+
+/*
+ * Return a high guess at the load of a migration-target cpu weighted
+ * according to the scheduling class and "nice" value.
+ */
+static unsigned long target_load(int cpu, int type)
+{
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long total = weighted_cpuload(cpu);
+
+       if (type == 0 || !sched_feat(LB_BIAS))
+               return total;
+
+       return max(rq->cpu_load[type-1], total);
+}
+
+/*
+ * find_idlest_group finds and returns the least busy CPU group within the
+ * domain.
+ */
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+{
+       struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
+       unsigned long min_load = ULONG_MAX, this_load = 0;
+       int load_idx = sd->forkexec_idx;
+       int imbalance = 100 + (sd->imbalance_pct-100)/2;
+
+       do {
+               unsigned long load, avg_load;
+               int local_group;
+               int i;
+
+               /* Skip over this group if it has no CPUs allowed */
+               if (!cpus_intersects(group->cpumask, p->cpus_allowed))
+                       continue;
+
+               local_group = cpu_isset(this_cpu, group->cpumask);
+
+               /* Tally up the load of all CPUs in the group */
+               avg_load = 0;
+
+               for_each_cpu_mask_nr(i, group->cpumask) {
+                       /* Bias balancing toward cpus of our domain */
+                       if (local_group)
+                               load = source_load(i, load_idx);
+                       else
+                               load = target_load(i, load_idx);
+
+                       avg_load += load;
+               }
+
+               /* Adjust by relative CPU power of the group */
+               avg_load = sg_div_cpu_power(group,
+                               avg_load * SCHED_LOAD_SCALE);
+
+               if (local_group) {
+                       this_load = avg_load;
+                       this = group;
+               } else if (avg_load < min_load) {
+                       min_load = avg_load;
+                       idlest = group;
+               }
+       } while (group = group->next, group != sd->groups);
+
+       if (!idlest || 100*this_load < imbalance*min_load)
+               return NULL;
+       return idlest;
+}
+
+/*
+ * find_idlest_cpu - find the idlest cpu among the cpus in group.
+ */
+static int
+find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu,
+               cpumask_t *tmp)
+{
+       unsigned long load, min_load = ULONG_MAX;
+       int idlest = -1;
+       int i;
+
+       /* Traverse only the allowed CPUs */
+       cpus_and(*tmp, group->cpumask, p->cpus_allowed);
+
+       for_each_cpu_mask_nr(i, *tmp) {
+               load = weighted_cpuload(i);
+
+               if (load < min_load || (load == min_load && i == this_cpu)) {
+                       min_load = load;
+                       idlest = i;
+               }
+       }
+
+       return idlest;
+}
+
+/*
+ * sched_balance_self: balance the current task (running on cpu) in domains
+ * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
+ * SD_BALANCE_EXEC.
+ *
+ * Balance, ie. select the least loaded group.
+ *
+ * Returns the target CPU number, or the same CPU if no balancing is needed.
+ *
+ * preempt must be disabled.
+ */
+static int sched_balance_self(int cpu, int flag)
+{
+       struct task_struct *t = current;
+       struct sched_domain *tmp, *sd = NULL;
+
+       for_each_domain(cpu, tmp) {
+               /*
+                * If power savings logic is enabled for a domain, stop there.
+                */
+               if (tmp->flags & SD_POWERSAVINGS_BALANCE)
+                       break;
+               if (tmp->flags & flag)
+                       sd = tmp;
+       }
+
+       if (sd)
+               update_shares(sd);
+
+       while (sd) {
+               cpumask_t span, tmpmask;
+               struct sched_group *group;
+               int new_cpu, weight;
+
+               if (!(sd->flags & flag)) {
+                       sd = sd->child;
+                       continue;
+               }
+
+               span = sd->span;
+               group = find_idlest_group(sd, t, cpu);
+               if (!group) {
+                       sd = sd->child;
+                       continue;
+               }
+
+               new_cpu = find_idlest_cpu(group, t, cpu, &tmpmask);
+               if (new_cpu == -1 || new_cpu == cpu) {
+                       /* Now try balancing at a lower domain level of cpu */
+                       sd = sd->child;
+                       continue;
+               }
+
+               /* Now try balancing at a lower domain level of new_cpu */
+               cpu = new_cpu;
+               sd = NULL;
+               weight = cpus_weight(span);
+               for_each_domain(cpu, tmp) {
+                       if (weight <= cpus_weight(tmp->span))
+                               break;
+                       if (tmp->flags & flag)
+                               sd = tmp;
+               }
+               /* while loop will break here if sd == NULL */
+       }
+
+       return cpu;
+}
+
+#endif /* CONFIG_SMP */
+
+/***
+ * try_to_wake_up - wake up a thread
+ * @p: the to-be-woken-up thread
+ * @state: the mask of task states that can be woken
+ * @sync: do a synchronous wakeup?
+ *
+ * Put it on the run-queue if it's not already there. The "current"
+ * thread is always on the run-queue (except when the actual
+ * re-schedule is in progress), and as such you're allowed to do
+ * the simpler "current->state = TASK_RUNNING" to mark yourself
+ * runnable without the overhead of this.
+ *
+ * returns failure only if the task is already active.
+ */
+static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
+{
+       int cpu, orig_cpu, this_cpu, success = 0;
+       unsigned long flags;
+       long old_state;
+       struct rq *rq;
+
+       if (!sched_feat(SYNC_WAKEUPS))
+               sync = 0;
+
+#ifdef CONFIG_SMP
+       if (sched_feat(LB_WAKEUP_UPDATE)) {
+               struct sched_domain *sd;
+
+               this_cpu = raw_smp_processor_id();
+               cpu = task_cpu(p);
+
+               for_each_domain(this_cpu, sd) {
+                       if (cpu_isset(cpu, sd->span)) {
+                               update_shares(sd);
+                               break;
+                       }
+               }
+       }
+#endif
+
+       smp_wmb();
+       rq = task_rq_lock(p, &flags);
+       old_state = p->state;
+       if (!(old_state & state))
+               goto out;
+
+       if (p->se.on_rq)
+               goto out_running;
+
+       cpu = task_cpu(p);
+       orig_cpu = cpu;
+       this_cpu = smp_processor_id();
+
+#ifdef CONFIG_SMP
+       if (unlikely(task_running(rq, p)))
+               goto out_activate;
+
+       cpu = p->sched_class->select_task_rq(p, sync);
+       if (cpu != orig_cpu) {
+               set_task_cpu(p, cpu);
+               task_rq_unlock(rq, &flags);
+               /* might preempt at this point */
+               rq = task_rq_lock(p, &flags);
+               old_state = p->state;
+
+       /* we need to unhold suspended tasks
+       if (old_state & TASK_ONHOLD) {
+               vx_unhold_task(p, rq);
+               old_state = p->state;
+       } */
+               if (!(old_state & state))
+                       goto out;
+               if (p->se.on_rq)
+                       goto out_running;
+
+               this_cpu = smp_processor_id();
+               cpu = task_cpu(p);
+       }
+
+#ifdef CONFIG_SCHEDSTATS
+       schedstat_inc(rq, ttwu_count);
+       if (cpu == this_cpu)
+               schedstat_inc(rq, ttwu_local);
+       else {
+               struct sched_domain *sd;
+               for_each_domain(this_cpu, sd) {
+                       if (cpu_isset(cpu, sd->span)) {
+                               schedstat_inc(sd, ttwu_wake_remote);
+                               break;
+                       }
+               }
+       }
+#endif /* CONFIG_SCHEDSTATS */
+
+out_activate:
+#endif /* CONFIG_SMP */
+       schedstat_inc(p, se.nr_wakeups);
+       if (sync)
+               schedstat_inc(p, se.nr_wakeups_sync);
+       if (orig_cpu != cpu)
+               schedstat_inc(p, se.nr_wakeups_migrate);
+       if (cpu == this_cpu)
+               schedstat_inc(p, se.nr_wakeups_local);
+       else
+               schedstat_inc(p, se.nr_wakeups_remote);
+       update_rq_clock(rq);
+       activate_task(rq, p, 1);
+       success = 1;
+
+out_running:
+       trace_mark(kernel_sched_wakeup,
+               "pid %d state %ld ## rq %p task %p rq->curr %p",
+               p->pid, p->state, rq, p, rq->curr);
+       check_preempt_curr(rq, p);
+
+       p->state = TASK_RUNNING;
+#ifdef CONFIG_SMP
+       if (p->sched_class->task_wake_up)
+               p->sched_class->task_wake_up(rq, p);
+#endif
+out:
+       current->se.last_wakeup = current->se.sum_exec_runtime;
+
+       task_rq_unlock(rq, &flags);
+
+       return success;
+}
+
+int wake_up_process(struct task_struct *p)
+{
+       return try_to_wake_up(p, TASK_ALL, 0);
+}
+EXPORT_SYMBOL(wake_up_process);
+
+int wake_up_state(struct task_struct *p, unsigned int state)
+{
+       return try_to_wake_up(p, state, 0);
+}
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
+ */
+static void __sched_fork(struct task_struct *p)
+{
+       p->se.exec_start                = 0;
+       p->se.sum_exec_runtime          = 0;
+       p->se.prev_sum_exec_runtime     = 0;
+       p->se.last_wakeup               = 0;
+       p->se.avg_overlap               = 0;
+
+#ifdef CONFIG_SCHEDSTATS
+       p->se.wait_start                = 0;
+       p->se.sum_sleep_runtime         = 0;
+       p->se.sleep_start               = 0;
+       p->se.block_start               = 0;
+       p->se.sleep_max                 = 0;
+       p->se.block_max                 = 0;
+       p->se.exec_max                  = 0;
+       p->se.slice_max                 = 0;
+       p->se.wait_max                  = 0;
+#endif
+
+       INIT_LIST_HEAD(&p->rt.run_list);
+       p->se.on_rq = 0;
+       INIT_LIST_HEAD(&p->se.group_node);
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+       INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+
+       /*
+        * We mark the process as running here, but have not actually
+        * inserted it onto the runqueue yet. This guarantees that
+        * nobody will actually run it, and a signal or other external
+        * event cannot wake it up and insert it on the runqueue either.
+        */
+       p->state = TASK_RUNNING;
+}
+
+/*
+ * fork()/clone()-time setup:
+ */
+void sched_fork(struct task_struct *p, int clone_flags)
+{
+       int cpu = get_cpu();
+
+       __sched_fork(p);
+
+#ifdef CONFIG_SMP
+       cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
+#endif
+       set_task_cpu(p, cpu);
+
+       /*
+        * Make sure we do not leak PI boosting priority to the child:
+        */
+       p->prio = current->normal_prio;
+       if (!rt_prio(p->prio))
+               p->sched_class = &fair_sched_class;
+
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
+       if (likely(sched_info_on()))
+               memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
+       p->oncpu = 0;
+#endif
+#ifdef CONFIG_PREEMPT
+       /* Want to start with kernel preemption disabled. */
+       task_thread_info(p)->preempt_count = 1;
+#endif
+       put_cpu();
+}
+
+/*
+ * wake_up_new_task - wake up a newly created task for the first time.
+ *
+ * This function will do some initial scheduler statistics housekeeping
+ * that must be done for every newly created context, then puts the task
+ * on the runqueue and wakes it.
+ */
+void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
+{
+       unsigned long flags;
+       struct rq *rq;
+
+       rq = task_rq_lock(p, &flags);
+       BUG_ON(p->state != TASK_RUNNING);
+       update_rq_clock(rq);
+
+       p->prio = effective_prio(p);
+
+       if (!p->sched_class->task_new || !current->se.on_rq) {
+               activate_task(rq, p, 0);
+       } else {
+               /*
+                * Let the scheduling class do new task startup
+                * management (if any):
+                */
+               p->sched_class->task_new(rq, p);
+               inc_nr_running(rq);
+       }
+       trace_mark(kernel_sched_wakeup_new,
+               "pid %d state %ld ## rq %p task %p rq->curr %p",
+               p->pid, p->state, rq, p, rq->curr);
+       check_preempt_curr(rq, p);
+#ifdef CONFIG_SMP
+       if (p->sched_class->task_wake_up)
+               p->sched_class->task_wake_up(rq, p);
+#endif
+       task_rq_unlock(rq, &flags);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+/**
+ * preempt_notifier_register - tell me when current is being being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+       hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+       hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+       struct preempt_notifier *notifier;
+       struct hlist_node *node;
+
+       hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+               notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+                                struct task_struct *next)
+{
+       struct preempt_notifier *notifier;
+       struct hlist_node *node;
+
+       hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+               notifier->ops->sched_out(notifier, next);
+}
+
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+                                struct task_struct *next)
+{
+}
+
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
+
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @prev: the current task that is being switched out
+ * @next: the task we are going to switch to.
+ *
+ * This is called with the rq lock held and interrupts off. It must
+ * be paired with a subsequent finish_task_switch after the context
+ * switch.
+ *
+ * prepare_task_switch sets up locking and calls architecture specific
+ * hooks.
+ */
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+                   struct task_struct *next)
+{
+       fire_sched_out_preempt_notifiers(prev, next);
+       prepare_lock_switch(rq, next);
+       prepare_arch_switch(next);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @rq: runqueue associated with task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * finish_task_switch must be called after the context switch, paired
+ * with a prepare_task_switch call before the context switch.
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
+ * and do any other architecture-specific cleanup actions.
+ *
+ * Note that we may have delayed dropping an mm in context_switch(). If
+ * so, we finish that here outside of the runqueue lock. (Doing it
+ * with the lock held can cause deadlocks; see schedule() for
+ * details.)
+ */
+static void finish_task_switch(struct rq *rq, struct task_struct *prev)
+       __releases(rq->lock)
+{
+       struct mm_struct *mm = rq->prev_mm;
+       long prev_state;
+
+       rq->prev_mm = NULL;
+
+       /*
+        * A task struct has one reference for the use as "current".
+        * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+        * schedule one last time. The schedule call will never return, and
+        * the scheduled task must drop that reference.
+        * The test for TASK_DEAD must occur while the runqueue locks are
+        * still held, otherwise prev could be scheduled on another cpu, die
+        * there before we look at prev->state, and then the reference would
+        * be dropped twice.
+        *              Manfred Spraul <manfred@colorfullife.com>
+        */
+       prev_state = prev->state;
+       finish_arch_switch(prev);
+       finish_lock_switch(rq, prev);
+#ifdef CONFIG_SMP
+       if (current->sched_class->post_schedule)
+               current->sched_class->post_schedule(rq);
+#endif
+
+       fire_sched_in_preempt_notifiers(current);
+       if (mm)
+               mmdrop(mm);
+       if (unlikely(prev_state == TASK_DEAD)) {
+               /*
+                * Remove function-return probe instances associated with this
+                * task and put them back on the free list.
+                */
+               kprobe_flush_task(prev);
+               put_task_struct(prev);
+       }
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage void schedule_tail(struct task_struct *prev)
+       __releases(rq->lock)
+{
+       struct rq *rq = this_rq();
+
+       finish_task_switch(rq, prev);
+#ifdef __ARCH_WANT_UNLOCKED_CTXSW
+       /* In this case, finish_task_switch does not reenable preemption */
+       preempt_enable();
+#endif
+       if (current->set_child_tid)
+               put_user(task_pid_vnr(current), current->set_child_tid);
+}
+
+/*
+ * context_switch - switch to the new MM and the new
+ * thread's register state.
+ */
+static inline void
+context_switch(struct rq *rq, struct task_struct *prev,
+              struct task_struct *next)
+{
+       struct mm_struct *mm, *oldmm;
+
+       prepare_task_switch(rq, prev, next);
+       trace_mark(kernel_sched_schedule,
+               "prev_pid %d next_pid %d prev_state %ld "
+               "## rq %p prev %p next %p",
+               prev->pid, next->pid, prev->state,
+               rq, prev, next);
+       mm = next->mm;
+       oldmm = prev->active_mm;
+       /*
+        * For paravirt, this is coupled with an exit in switch_to to
+        * combine the page table reload and the switch backend into
+        * one hypercall.
+        */
+       arch_enter_lazy_cpu_mode();
+
+       if (unlikely(!mm)) {
+               next->active_mm = oldmm;
+               atomic_inc(&oldmm->mm_count);
+               enter_lazy_tlb(oldmm, next);
+       } else
+               switch_mm(oldmm, mm, next);
+
+       if (unlikely(!prev->mm)) {
+               prev->active_mm = NULL;
+               rq->prev_mm = oldmm;
+       }
+       /*
+        * Since the runqueue lock will be released by the next
+        * task (which is an invalid locking op but in the case
+        * of the scheduler it's an obvious special-case), so we
+        * do an early lockdep release here:
+        */
+#ifndef __ARCH_WANT_UNLOCKED_CTXSW
+       spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
+#endif
+
+       /* Here we just switch the register state and the stack. */
+       switch_to(prev, next, prev);
+
+       barrier();
+       /*
+        * this_rq must be evaluated again because prev may have moved
+        * CPUs since it called schedule(), thus the 'rq' on its stack
+        * frame will be invalid.
+        */
+       finish_task_switch(this_rq(), prev);
+}
+
+/*
+ * nr_running, nr_uninterruptible and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, current number of uninterruptible-sleeping threads, total
+ * number of context switches performed since bootup.
+ */
+unsigned long nr_running(void)
+{
+       unsigned long i, sum = 0;
+
+       for_each_online_cpu(i)
+               sum += cpu_rq(i)->nr_running;
+
+       return sum;
+}
+
+unsigned long nr_uninterruptible(void)
+{
+       unsigned long i, sum = 0;
+
+       for_each_possible_cpu(i)
+               sum += cpu_rq(i)->nr_uninterruptible;
+
+       /*
+        * Since we read the counters lockless, it might be slightly
+        * inaccurate. Do not allow it to go below zero though:
+        */
+       if (unlikely((long)sum < 0))
+               sum = 0;
+
+       return sum;
+}
+
+unsigned long long nr_context_switches(void)
+{
+       int i;
+       unsigned long long sum = 0;
+
+       for_each_possible_cpu(i)
+               sum += cpu_rq(i)->nr_switches;
+
+       return sum;
+}
+
+unsigned long nr_iowait(void)
+{
+       unsigned long i, sum = 0;
+
+       for_each_possible_cpu(i)
+               sum += atomic_read(&cpu_rq(i)->nr_iowait);
+
+       return sum;
+}
+
+unsigned long nr_active(void)
+{
+       unsigned long i, running = 0, uninterruptible = 0;
+
+       for_each_online_cpu(i) {
+               running += cpu_rq(i)->nr_running;
+               uninterruptible += cpu_rq(i)->nr_uninterruptible;
+       }
+
+       if (unlikely((long)uninterruptible < 0))
+               uninterruptible = 0;
+
+       return running + uninterruptible;
+}
+
+/*
+ * Update rq->cpu_load[] statistics. This function is usually called every
+ * scheduler tick (TICK_NSEC).
+ */
+static void update_cpu_load(struct rq *this_rq)
+{
+       unsigned long this_load = this_rq->load.weight;
+       int i, scale;
+
+       this_rq->nr_load_updates++;
+
+       /* Update our load: */
+       for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
+               unsigned long old_load, new_load;
+
+               /* scale is effectively 1 << i now, and >> i divides by scale */
+
+               old_load = this_rq->cpu_load[i];
+               new_load = this_load;
+               /*
+                * Round up the averaging division if load is increasing. This
+                * prevents us from getting stuck on 9 if the load is 10, for
+                * example.
+                */
+               if (new_load > old_load)
+                       new_load += scale-1;
+               this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
+       }
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * double_rq_lock - safely lock two runqueues
+ *
+ * Note this does not disable interrupts like task_rq_lock,
+ * you need to do so manually before calling.
+ */
+static void double_rq_lock(struct rq *rq1, struct rq *rq2)
+       __acquires(rq1->lock)
+       __acquires(rq2->lock)
+{
+       BUG_ON(!irqs_disabled());
+       if (rq1 == rq2) {
+               spin_lock(&rq1->lock);
+               __acquire(rq2->lock);   /* Fake it out ;) */
+       } else {
+               if (rq1 < rq2) {
+                       spin_lock(&rq1->lock);
+                       spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
+               } else {
+                       spin_lock(&rq2->lock);
+                       spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
+               }
+       }
+       update_rq_clock(rq1);
+       update_rq_clock(rq2);
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+       __releases(rq1->lock)
+       __releases(rq2->lock)
+{
+       spin_unlock(&rq1->lock);
+       if (rq1 != rq2)
+               spin_unlock(&rq2->lock);
+       else
+               __release(rq2->lock);
+}
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+       __releases(this_rq->lock)
+       __acquires(busiest->lock)
+       __acquires(this_rq->lock)
+{
+       int ret = 0;
+
+       if (unlikely(!irqs_disabled())) {
+               /* printk() doesn't work good under rq->lock */
+               spin_unlock(&this_rq->lock);
+               BUG_ON(1);
+       }
+       if (unlikely(!spin_trylock(&busiest->lock))) {
+               if (busiest < this_rq) {
+                       spin_unlock(&this_rq->lock);
+                       spin_lock(&busiest->lock);
+                       spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
+                       ret = 1;
+               } else
+                       spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
+       }
+       return ret;
+}
+
+static void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
+       __releases(busiest->lock)
+{
+       spin_unlock(&busiest->lock);
+       lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
+}
+
+/*
+ * If dest_cpu is allowed for this process, migrate the task to it.
+ * This is accomplished by forcing the cpu_allowed mask to only
+ * allow dest_cpu, which will force the cpu onto dest_cpu. Then
+ * the cpu_allowed mask is restored.
+ */
+static void sched_migrate_task(struct task_struct *p, int dest_cpu)
+{
+       struct migration_req req;
+       unsigned long flags;
+       struct rq *rq;
+
+       rq = task_rq_lock(p, &flags);
+       if (!cpu_isset(dest_cpu, p->cpus_allowed)
+           || unlikely(!cpu_active(dest_cpu)))
+               goto out;
+
+       /* force the process onto the specified CPU */
+       if (migrate_task(p, dest_cpu, &req)) {
+               /* Need to wait for migration thread (might exit: take ref). */
+               struct task_struct *mt = rq->migration_thread;
+
+               get_task_struct(mt);
+               task_rq_unlock(rq, &flags);
+               wake_up_process(mt);
+               put_task_struct(mt);
+               wait_for_completion(&req.done);
+
+               return;
+       }
+out:
+       task_rq_unlock(rq, &flags);
+}
+
+/*
+ * sched_exec - execve() is a valuable balancing opportunity, because at
+ * this point the task has the smallest effective memory and cache footprint.
+ */
+void sched_exec(void)
+{
+       int new_cpu, this_cpu = get_cpu();
+       new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
+       put_cpu();
+       if (new_cpu != this_cpu)
+               sched_migrate_task(current, new_cpu);
+}
+
+/*
+ * pull_task - move a task from a remote runqueue to the local runqueue.
+ * Both runqueues must be locked.
+ */
+static void pull_task(struct rq *src_rq, struct task_struct *p,
+                     struct rq *this_rq, int this_cpu)
+{
+       deactivate_task(src_rq, p, 0);
+       set_task_cpu(p, this_cpu);
+       activate_task(this_rq, p, 0);
+       /*
+        * Note that idle threads have a prio of MAX_PRIO, for this test
+        * to be always true for them.
+        */
+       check_preempt_curr(this_rq, p);
+}
+
+/*
+ * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ */
+static
+int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
+                    struct sched_domain *sd, enum cpu_idle_type idle,
+                    int *all_pinned)
+{
+       /*
+        * We do not migrate tasks that are:
+        * 1) running (obviously), or
+        * 2) cannot be migrated to this CPU due to cpus_allowed, or
+        * 3) are cache-hot on their current CPU.
+        */
+       if (!cpu_isset(this_cpu, p->cpus_allowed)) {
+               schedstat_inc(p, se.nr_failed_migrations_affine);
+               return 0;
+       }
+       *all_pinned = 0;
+
+       if (task_running(rq, p)) {
+               schedstat_inc(p, se.nr_failed_migrations_running);
+               return 0;
+       }
+
+       /*
+        * Aggressive migration if:
+        * 1) task is cache cold, or
+        * 2) too many balance attempts have failed.
+        */
+
+       if (!task_hot(p, rq->clock, sd) ||
+                       sd->nr_balance_failed > sd->cache_nice_tries) {
+#ifdef CONFIG_SCHEDSTATS
+               if (task_hot(p, rq->clock, sd)) {
+                       schedstat_inc(sd, lb_hot_gained[idle]);
+                       schedstat_inc(p, se.nr_forced_migrations);
+               }
+#endif
+               return 1;
+       }
+
+       if (task_hot(p, rq->clock, sd)) {
+               schedstat_inc(p, se.nr_failed_migrations_hot);
+               return 0;
+       }
+       return 1;
+}
+
+static unsigned long
+balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+             unsigned long max_load_move, struct sched_domain *sd,
+             enum cpu_idle_type idle, int *all_pinned,
+             int *this_best_prio, struct rq_iterator *iterator)
+{
+       int loops = 0, pulled = 0, pinned = 0;
+       struct task_struct *p;
+       long rem_load_move = max_load_move;
+
+       if (max_load_move == 0)
+               goto out;
+
+       pinned = 1;
+
+       /*
+        * Start the load-balancing iterator:
+        */
+       p = iterator->start(iterator->arg);
+next:
+       if (!p || loops++ > sysctl_sched_nr_migrate)
+               goto out;
+
+       if ((p->se.load.weight >> 1) > rem_load_move ||
+           !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
+               p = iterator->next(iterator->arg);
+               goto next;
+       }
+
+       pull_task(busiest, p, this_rq, this_cpu);
+       pulled++;
+       rem_load_move -= p->se.load.weight;
+
+       /*
+        * We only want to steal up to the prescribed amount of weighted load.
+        */
+       if (rem_load_move > 0) {
+               if (p->prio < *this_best_prio)
+                       *this_best_prio = p->prio;
+               p = iterator->next(iterator->arg);
+               goto next;
+       }
+out:
+       /*
+        * Right now, this is one of only two places pull_task() is called,
+        * so we can safely collect pull_task() stats here rather than
+        * inside pull_task().
+        */
+       schedstat_add(sd, lb_gained[idle], pulled);
+
+       if (all_pinned)
+               *all_pinned = pinned;
+
+       return max_load_move - rem_load_move;
+}
+
+/*
+ * move_tasks tries to move up to max_load_move weighted load from busiest to
+ * this_rq, as part of a balancing operation within domain "sd".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+                     unsigned long max_load_move,
+                     struct sched_domain *sd, enum cpu_idle_type idle,
+                     int *all_pinned)
+{
+       const struct sched_class *class = sched_class_highest;
+       unsigned long total_load_moved = 0;
+       int this_best_prio = this_rq->curr->prio;
+
+       do {
+               total_load_moved +=
+                       class->load_balance(this_rq, this_cpu, busiest,
+                               max_load_move - total_load_moved,
+                               sd, idle, all_pinned, &this_best_prio);
+               class = class->next;
+
+               if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
+                       break;
+
+       } while (class && max_load_move > total_load_moved);
+
+       return total_load_moved > 0;
+}
+
+static int
+iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+                  struct sched_domain *sd, enum cpu_idle_type idle,
+                  struct rq_iterator *iterator)
+{
+       struct task_struct *p = iterator->start(iterator->arg);
+       int pinned = 0;
+
+       while (p) {
+               if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
+                       pull_task(busiest, p, this_rq, this_cpu);
+                       /*
+                        * Right now, this is only the second place pull_task()
+                        * is called, so we can safely collect pull_task()
+                        * stats here rather than inside pull_task().
+                        */
+                       schedstat_inc(sd, lb_gained[idle]);
+
+                       return 1;
+               }
+               p = iterator->next(iterator->arg);
+       }
+
+       return 0;
+}
+
+/*
+ * move_one_task tries to move exactly one task from busiest to this_rq, as
+ * part of active balancing operations within "domain".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+                        struct sched_domain *sd, enum cpu_idle_type idle)
+{
+       const struct sched_class *class;
+
+       for (class = sched_class_highest; class; class = class->next)
+               if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
+                       return 1;
+
+       return 0;
+}
+
+/*
+ * find_busiest_group finds and returns the busiest CPU group within the
+ * domain. It calculates and returns the amount of weighted load which
+ * should be moved to restore balance via the imbalance parameter.
+ */
+static struct sched_group *
+find_busiest_group(struct sched_domain *sd, int this_cpu,
+                  unsigned long *imbalance, enum cpu_idle_type idle,
+                  int *sd_idle, const cpumask_t *cpus, int *balance)
+{
+       struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
+       unsigned long max_load, avg_load, total_load, this_load, total_pwr;
+       unsigned long max_pull;
+       unsigned long busiest_load_per_task, busiest_nr_running;
+       unsigned long this_load_per_task, this_nr_running;
+       int load_idx, group_imb = 0;
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+       int power_savings_balance = 1;
+       unsigned long leader_nr_running = 0, min_load_per_task = 0;
+       unsigned long min_nr_running = ULONG_MAX;
+       struct sched_group *group_min = NULL, *group_leader = NULL;
+#endif
+
+       max_load = this_load = total_load = total_pwr = 0;
+       busiest_load_per_task = busiest_nr_running = 0;
+       this_load_per_task = this_nr_running = 0;
+
+       if (idle == CPU_NOT_IDLE)
+               load_idx = sd->busy_idx;
+       else if (idle == CPU_NEWLY_IDLE)
+               load_idx = sd->newidle_idx;
+       else
+               load_idx = sd->idle_idx;
+
+       do {
+               unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
+               int local_group;
+               int i;
+               int __group_imb = 0;
+               unsigned int balance_cpu = -1, first_idle_cpu = 0;
+               unsigned long sum_nr_running, sum_weighted_load;
+               unsigned long sum_avg_load_per_task;
+               unsigned long avg_load_per_task;
+
+               local_group = cpu_isset(this_cpu, group->cpumask);
+
+               if (local_group)
+                       balance_cpu = first_cpu(group->cpumask);
+
+               /* Tally up the load of all CPUs in the group */
+               sum_weighted_load = sum_nr_running = avg_load = 0;
+               sum_avg_load_per_task = avg_load_per_task = 0;
+
+               max_cpu_load = 0;
+               min_cpu_load = ~0UL;
+
+               for_each_cpu_mask_nr(i, group->cpumask) {
+                       struct rq *rq;
+
+                       if (!cpu_isset(i, *cpus))
+                               continue;
+
+                       rq = cpu_rq(i);
+
+                       if (*sd_idle && rq->nr_running)
+                               *sd_idle = 0;
+
+                       /* Bias balancing toward cpus of our domain */
+                       if (local_group) {
+                               if (idle_cpu(i) && !first_idle_cpu) {
+                                       first_idle_cpu = 1;
+                                       balance_cpu = i;
+                               }
+
+                               load = target_load(i, load_idx);
+                       } else {
+                               load = source_load(i, load_idx);
+                               if (load > max_cpu_load)
+                                       max_cpu_load = load;
+                               if (min_cpu_load > load)
+                                       min_cpu_load = load;
+                       }
+
+                       avg_load += load;
+                       sum_nr_running += rq->nr_running;
+                       sum_weighted_load += weighted_cpuload(i);
+
+                       sum_avg_load_per_task += cpu_avg_load_per_task(i);
+               }
+
+               /*
+                * First idle cpu or the first cpu(busiest) in this sched group
+                * is eligible for doing load balancing at this and above
+                * domains. In the newly idle case, we will allow all the cpu's
+                * to do the newly idle load balance.
+                */
+               if (idle != CPU_NEWLY_IDLE && local_group &&
+                   balance_cpu != this_cpu && balance) {
+                       *balance = 0;
+                       goto ret;
+               }
+
+               total_load += avg_load;
+               total_pwr += group->__cpu_power;
+
+               /* Adjust by relative CPU power of the group */
+               avg_load = sg_div_cpu_power(group,
+                               avg_load * SCHED_LOAD_SCALE);
+
+
+               /*
+                * Consider the group unbalanced when the imbalance is larger
+                * than the average weight of two tasks.
+                *
+                * APZ: with cgroup the avg task weight can vary wildly and
+                *      might not be a suitable number - should we keep a
+                *      normalized nr_running number somewhere that negates
+                *      the hierarchy?
+                */
+               avg_load_per_task = sg_div_cpu_power(group,
+                               sum_avg_load_per_task * SCHED_LOAD_SCALE);
+
+               if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
+                       __group_imb = 1;
+
+               group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
+
+               if (local_group) {
+                       this_load = avg_load;
+                       this = group;
+                       this_nr_running = sum_nr_running;
+                       this_load_per_task = sum_weighted_load;
+               } else if (avg_load > max_load &&
+                          (sum_nr_running > group_capacity || __group_imb)) {
+                       max_load = avg_load;
+                       busiest = group;
+                       busiest_nr_running = sum_nr_running;
+                       busiest_load_per_task = sum_weighted_load;
+                       group_imb = __group_imb;
+               }
+
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+               /*
+                * Busy processors will not participate in power savings
+                * balance.
+                */
+               if (idle == CPU_NOT_IDLE ||
+                               !(sd->flags & SD_POWERSAVINGS_BALANCE))
+                       goto group_next;
+
+               /*
+                * If the local group is idle or completely loaded
+                * no need to do power savings balance at this domain
+                */
+               if (local_group && (this_nr_running >= group_capacity ||
+                                   !this_nr_running))
+                       power_savings_balance = 0;
+
+               /*
+                * If a group is already running at full capacity or idle,
+                * don't include that group in power savings calculations
+                */
+               if (!power_savings_balance || sum_nr_running >= group_capacity
+                   || !sum_nr_running)
+                       goto group_next;
+
+               /*
+                * Calculate the group which has the least non-idle load.
+                * This is the group from where we need to pick up the load
+                * for saving power
+                */
+               if ((sum_nr_running < min_nr_running) ||
+                   (sum_nr_running == min_nr_running &&
+                    first_cpu(group->cpumask) <
+                    first_cpu(group_min->cpumask))) {
+                       group_min = group;
+                       min_nr_running = sum_nr_running;
+                       min_load_per_task = sum_weighted_load /
+                                               sum_nr_running;
+               }
+
+               /*
+                * Calculate the group which is almost near its
+                * capacity but still has some space to pick up some load
+                * from other group and save more power
+                */
+               if (sum_nr_running <= group_capacity - 1) {
+                       if (sum_nr_running > leader_nr_running ||
+                           (sum_nr_running == leader_nr_running &&
+                            first_cpu(group->cpumask) >
+                             first_cpu(group_leader->cpumask))) {
+                               group_leader = group;
+                               leader_nr_running = sum_nr_running;
+                       }
+               }
+group_next:
+#endif
+               group = group->next;
+       } while (group != sd->groups);
+
+       if (!busiest || this_load >= max_load || busiest_nr_running == 0)
+               goto out_balanced;
+
+       avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
+
+       if (this_load >= avg_load ||
+                       100*max_load <= sd->imbalance_pct*this_load)
+               goto out_balanced;
+
+       busiest_load_per_task /= busiest_nr_running;
+       if (group_imb)
+               busiest_load_per_task = min(busiest_load_per_task, avg_load);
+
+       /*
+        * We're trying to get all the cpus to the average_load, so we don't
+        * want to push ourselves above the average load, nor do we wish to
+        * reduce the max loaded cpu below the average load, as either of these
+        * actions would just result in more rebalancing later, and ping-pong
+        * tasks around. Thus we look for the minimum possible imbalance.
+        * Negative imbalances (*we* are more loaded than anyone else) will
+        * be counted as no imbalance for these purposes -- we can't fix that
+        * by pulling tasks to us. Be careful of negative numbers as they'll
+        * appear as very large values with unsigned longs.
+        */
+       if (max_load <= busiest_load_per_task)
+               goto out_balanced;
+
+       /*
+        * In the presence of smp nice balancing, certain scenarios can have
+        * max load less than avg load(as we skip the groups at or below
+        * its cpu_power, while calculating max_load..)
+        */
+       if (max_load < avg_load) {
+               *imbalance = 0;
+               goto small_imbalance;
+       }
+
+       /* Don't want to pull so many tasks that a group would go idle */
+       max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
+
+       /* How much load to actually move to equalise the imbalance */
+       *imbalance = min(max_pull * busiest->__cpu_power,
+                               (avg_load - this_load) * this->__cpu_power)
+                       / SCHED_LOAD_SCALE;
+
+       /*
+        * if *imbalance is less than the average load per runnable task
+        * there is no gaurantee that any tasks will be moved so we'll have
+        * a think about bumping its value to force at least one task to be
+        * moved
+        */
+       if (*imbalance < busiest_load_per_task) {
+               unsigned long tmp, pwr_now, pwr_move;
+               unsigned int imbn;
+
+small_imbalance:
+               pwr_move = pwr_now = 0;
+               imbn = 2;
+               if (this_nr_running) {
+                       this_load_per_task /= this_nr_running;
+                       if (busiest_load_per_task > this_load_per_task)
+                               imbn = 1;
+               } else
+                       this_load_per_task = cpu_avg_load_per_task(this_cpu);
+
+               if (max_load - this_load + 2*busiest_load_per_task >=
+                                       busiest_load_per_task * imbn) {
+                       *imbalance = busiest_load_per_task;
+                       return busiest;
+               }
+
+               /*
+                * OK, we don't have enough imbalance to justify moving tasks,
+                * however we may be able to increase total CPU power used by
+                * moving them.
+                */
+
+               pwr_now += busiest->__cpu_power *
+                               min(busiest_load_per_task, max_load);
+               pwr_now += this->__cpu_power *
+                               min(this_load_per_task, this_load);
+               pwr_now /= SCHED_LOAD_SCALE;
+
+               /* Amount of load we'd subtract */
+               tmp = sg_div_cpu_power(busiest,
+                               busiest_load_per_task * SCHED_LOAD_SCALE);
+               if (max_load > tmp)
+                       pwr_move += busiest->__cpu_power *
+                               min(busiest_load_per_task, max_load - tmp);
+
+               /* Amount of load we'd add */
+               if (max_load * busiest->__cpu_power <
+                               busiest_load_per_task * SCHED_LOAD_SCALE)
+                       tmp = sg_div_cpu_power(this,
+                                       max_load * busiest->__cpu_power);
+               else
+                       tmp = sg_div_cpu_power(this,
+                               busiest_load_per_task * SCHED_LOAD_SCALE);
+               pwr_move += this->__cpu_power *
+                               min(this_load_per_task, this_load + tmp);
+               pwr_move /= SCHED_LOAD_SCALE;
+
+               /* Move if we gain throughput */
+               if (pwr_move > pwr_now)
+                       *imbalance = busiest_load_per_task;
+       }
+
+       return busiest;
+
+out_balanced:
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+       if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
+               goto ret;
+
+       if (this == group_leader && group_leader != group_min) {
+               *imbalance = min_load_per_task;
+               return group_min;
+       }
+#endif
+ret:
+       *imbalance = 0;
+       return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the cpus in group.
+ */
+static struct rq *
+find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
+                  unsigned long imbalance, const cpumask_t *cpus)
+{
+       struct rq *busiest = NULL, *rq;
+       unsigned long max_load = 0;
+       int i;
+
+       for_each_cpu_mask_nr(i, group->cpumask) {
+               unsigned long wl;
+
+               if (!cpu_isset(i, *cpus))
+                       continue;
+
+               rq = cpu_rq(i);
+               wl = weighted_cpuload(i);
+
+               if (rq->nr_running == 1 && wl > imbalance)
+                       continue;
+
+               if (wl > max_load) {
+                       max_load = wl;
+                       busiest = rq;
+               }
+       }
+
+       return busiest;
+}
+
+/*
+ * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
+ * so long as it is large enough.
+ */
+#define MAX_PINNED_INTERVAL    512
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ */
+static int load_balance(int this_cpu, struct rq *this_rq,
+                       struct sched_domain *sd, enum cpu_idle_type idle,
+                       int *balance, cpumask_t *cpus)
+{
+       int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
+       struct sched_group *group;
+       unsigned long imbalance;
+       struct rq *busiest;
+       unsigned long flags;
+
+       cpus_setall(*cpus);
+
+       /*
+        * When power savings policy is enabled for the parent domain, idle
+        * sibling can pick up load irrespective of busy siblings. In this case,
+        * let the state of idle sibling percolate up as CPU_IDLE, instead of
+        * portraying it as CPU_NOT_IDLE.
+        */
+       if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
+           !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+               sd_idle = 1;
+
+       schedstat_inc(sd, lb_count[idle]);
+
+redo:
+       update_shares(sd);
+       group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
+                                  cpus, balance);
+
+       if (*balance == 0)
+               goto out_balanced;
+
+       if (!group) {
+               schedstat_inc(sd, lb_nobusyg[idle]);
+               goto out_balanced;
+       }
+
+       busiest = find_busiest_queue(group, idle, imbalance, cpus);
+       if (!busiest) {
+               schedstat_inc(sd, lb_nobusyq[idle]);
+               goto out_balanced;
+       }
+
+       BUG_ON(busiest == this_rq);
+
+       schedstat_add(sd, lb_imbalance[idle], imbalance);
+
+       ld_moved = 0;
+       if (busiest->nr_running > 1) {
+               /*
+                * Attempt to move tasks. If find_busiest_group has found
+                * an imbalance but busiest->nr_running <= 1, the group is
+                * still unbalanced. ld_moved simply stays zero, so it is
+                * correctly treated as an imbalance.
+                */
+               local_irq_save(flags);
+               double_rq_lock(this_rq, busiest);
+               ld_moved = move_tasks(this_rq, this_cpu, busiest,
+                                     imbalance, sd, idle, &all_pinned);
+               double_rq_unlock(this_rq, busiest);
+               local_irq_restore(flags);
+
+               /*
+                * some other cpu did the load balance for us.
+                */
+               if (ld_moved && this_cpu != smp_processor_id())
+                       resched_cpu(this_cpu);
+
+               /* All tasks on this runqueue were pinned by CPU affinity */
+               if (unlikely(all_pinned)) {
+                       cpu_clear(cpu_of(busiest), *cpus);
+                       if (!cpus_empty(*cpus))
+                               goto redo;
+                       goto out_balanced;
+               }
+       }
+
+       if (!ld_moved) {
+               schedstat_inc(sd, lb_failed[idle]);
+               sd->nr_balance_failed++;
+
+               if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
+
+                       spin_lock_irqsave(&busiest->lock, flags);
+
+                       /* don't kick the migration_thread, if the curr
+                        * task on busiest cpu can't be moved to this_cpu
+                        */
+                       if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
+                               spin_unlock_irqrestore(&busiest->lock, flags);
+                               all_pinned = 1;
+                               goto out_one_pinned;
+                       }
+
+                       if (!busiest->active_balance) {
+                               busiest->active_balance = 1;
+                               busiest->push_cpu = this_cpu;
+                               active_balance = 1;
+                       }
+                       spin_unlock_irqrestore(&busiest->lock, flags);
+                       if (active_balance)
+                               wake_up_process(busiest->migration_thread);
+
+                       /*
+                        * We've kicked active balancing, reset the failure
+                        * counter.
+                        */
+                       sd->nr_balance_failed = sd->cache_nice_tries+1;
+               }
+       } else
+               sd->nr_balance_failed = 0;
+
+       if (likely(!active_balance)) {
+               /* We were unbalanced, so reset the balancing interval */
+               sd->balance_interval = sd->min_interval;
+       } else {
+               /*
+                * If we've begun active balancing, start to back off. This
+                * case may not be covered by the all_pinned logic if there
+                * is only 1 task on the busy runqueue (because we don't call
+                * move_tasks).
+                */
+               if (sd->balance_interval < sd->max_interval)
+                       sd->balance_interval *= 2;
+       }
+
+       if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
+           !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+               ld_moved = -1;
+
+       goto out;
+
+out_balanced:
+       schedstat_inc(sd, lb_balanced[idle]);
+
+       sd->nr_balance_failed = 0;
+
+out_one_pinned:
+       /* tune up the balancing interval */
+       if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
+                       (sd->balance_interval < sd->max_interval))
+               sd->balance_interval *= 2;
+
+       if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
+           !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+               ld_moved = -1;
+       else
+               ld_moved = 0;
+out:
+       if (ld_moved)
+               update_shares(sd);
+       return ld_moved;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ *
+ * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
+ * this_rq is locked.
+ */
+static int
+load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
+                       cpumask_t *cpus)
+{
+       struct sched_group *group;
+       struct rq *busiest = NULL;
+       unsigned long imbalance;
+       int ld_moved = 0;
+       int sd_idle = 0;
+       int all_pinned = 0;
+
+       cpus_setall(*cpus);
+
+       /*
+        * When power savings policy is enabled for the parent domain, idle
+        * sibling can pick up load irrespective of busy siblings. In this case,
+        * let the state of idle sibling percolate up as IDLE, instead of
+        * portraying it as CPU_NOT_IDLE.
+        */
+       if (sd->flags & SD_SHARE_CPUPOWER &&
+           !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+               sd_idle = 1;
+
+       schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
+redo:
+       update_shares_locked(this_rq, sd);
+       group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
+                                  &sd_idle, cpus, NULL);
+       if (!group) {
+               schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
+               goto out_balanced;
+       }
+
+       busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
+       if (!busiest) {
+               schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
+               goto out_balanced;
+       }
+
+       BUG_ON(busiest == this_rq);
+
+       schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
+
+       ld_moved = 0;
+       if (busiest->nr_running > 1) {
+               /* Attempt to move tasks */
+               double_lock_balance(this_rq, busiest);
+               /* this_rq->clock is already updated */
+               update_rq_clock(busiest);
+               ld_moved = move_tasks(this_rq, this_cpu, busiest,
+                                       imbalance, sd, CPU_NEWLY_IDLE,
+                                       &all_pinned);
+               double_unlock_balance(this_rq, busiest);
+
+               if (unlikely(all_pinned)) {
+                       cpu_clear(cpu_of(busiest), *cpus);
+                       if (!cpus_empty(*cpus))
+                               goto redo;
+               }
+       }
+
+       if (!ld_moved) {
+               schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
+               if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
+                   !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+                       return -1;
+       } else
+               sd->nr_balance_failed = 0;
+
+       update_shares_locked(this_rq, sd);
+       return ld_moved;
+
+out_balanced:
+       schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
+       if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
+           !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
+               return -1;
+       sd->nr_balance_failed = 0;
+
+       return 0;
+}
+
+/*
+ * idle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ */
+static void idle_balance(int this_cpu, struct rq *this_rq)
+{
+       struct sched_domain *sd;
+       int pulled_task = -1;
+       unsigned long next_balance = jiffies + HZ;
+       cpumask_t tmpmask;
+
+       for_each_domain(this_cpu, sd) {
+               unsigned long interval;
+
+               if (!(sd->flags & SD_LOAD_BALANCE))
+                       continue;
+
+               if (sd->flags & SD_BALANCE_NEWIDLE)
+                       /* If we've pulled tasks over stop searching: */
+                       pulled_task = load_balance_newidle(this_cpu, this_rq,
+                                                          sd, &tmpmask);
+
+               interval = msecs_to_jiffies(sd->balance_interval);
+               if (time_after(next_balance, sd->last_balance + interval))
+                       next_balance = sd->last_balance + interval;
+               if (pulled_task)
+                       break;
+       }
+       if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
+               /*
+                * We are going idle. next_balance may be set based on
+                * a busy processor. So reset next_balance.
+                */
+               this_rq->next_balance = next_balance;
+       }
+}
+
+/*
+ * active_load_balance is run by migration threads. It pushes running tasks
+ * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
+ * running on each physical CPU where possible, and avoids physical /
+ * logical imbalances.
+ *
+ * Called with busiest_rq locked.
+ */
+static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
+{
+       int target_cpu = busiest_rq->push_cpu;
+       struct sched_domain *sd;
+       struct rq *target_rq;
+
+       /* Is there any task to move? */
+       if (busiest_rq->nr_running <= 1)
+               return;
+
+       target_rq = cpu_rq(target_cpu);
+
+       /*
+        * This condition is "impossible", if it occurs
+        * we need to fix it. Originally reported by
+        * Bjorn Helgaas on a 128-cpu setup.
+        */
+       BUG_ON(busiest_rq == target_rq);
+
+       /* move a task from busiest_rq to target_rq */
+       double_lock_balance(busiest_rq, target_rq);
+       update_rq_clock(busiest_rq);
+       update_rq_clock(target_rq);
+
+       /* Search for an sd spanning us and the target CPU. */
+       for_each_domain(target_cpu, sd) {
+               if ((sd->flags & SD_LOAD_BALANCE) &&
+                   cpu_isset(busiest_cpu, sd->span))
+                               break;
+       }
+
+       if (likely(sd)) {
+               schedstat_inc(sd, alb_count);
+
+               if (move_one_task(target_rq, target_cpu, busiest_rq,
+                                 sd, CPU_IDLE))
+                       schedstat_inc(sd, alb_pushed);
+               else
+                       schedstat_inc(sd, alb_failed);
+       }
+       double_unlock_balance(busiest_rq, target_rq);
+}
+
+#ifdef CONFIG_NO_HZ
+static struct {
+       atomic_t load_balancer;
+       cpumask_t cpu_mask;
+} nohz ____cacheline_aligned = {
+       .load_balancer = ATOMIC_INIT(-1),
+       .cpu_mask = CPU_MASK_NONE,
+};
+
+/*
+ * This routine will try to nominate the ilb (idle load balancing)
+ * owner among the cpus whose ticks are stopped. ilb owner will do the idle
+ * load balancing on behalf of all those cpus. If all the cpus in the system
+ * go into this tickless mode, then there will be no ilb owner (as there is
+ * no need for one) and all the cpus will sleep till the next wakeup event
+ * arrives...
+ *
+ * For the ilb owner, tick is not stopped. And this tick will be used
+ * for idle load balancing. ilb owner will still be part of
+ * nohz.cpu_mask..
+ *
+ * While stopping the tick, this cpu will become the ilb owner if there
+ * is no other owner. And will be the owner till that cpu becomes busy
+ * or if all cpus in the system stop their ticks at which point
+ * there is no need for ilb owner.
+ *
+ * When the ilb owner becomes busy, it nominates another owner, during the
+ * next busy scheduler_tick()
+ */
+int select_nohz_load_balancer(int stop_tick)
+{
+       int cpu = smp_processor_id();
+
+       if (stop_tick) {
+               cpu_set(cpu, nohz.cpu_mask);
+               cpu_rq(cpu)->in_nohz_recently = 1;
+
+               /*
+                * If we are going offline and still the leader, give up!
+                */
+               if (!cpu_active(cpu) &&
+                   atomic_read(&nohz.load_balancer) == cpu) {
+                       if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
+                               BUG();
+                       return 0;
+               }
+
+               /* time for ilb owner also to sleep */
+               if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+                       if (atomic_read(&nohz.load_balancer) == cpu)
+                               atomic_set(&nohz.load_balancer, -1);
+                       return 0;
+               }
+
+               if (atomic_read(&nohz.load_balancer) == -1) {
+                       /* make me the ilb owner */
+                       if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
+                               return 1;
+               } else if (atomic_read(&nohz.load_balancer) == cpu)
+                       return 1;
+       } else {
+               if (!cpu_isset(cpu, nohz.cpu_mask))
+                       return 0;
+
+               cpu_clear(cpu, nohz.cpu_mask);
+
+               if (atomic_read(&nohz.load_balancer) == cpu)
+                       if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
+                               BUG();
+       }
+       return 0;
+}
+#endif
+
+static DEFINE_SPINLOCK(balancing);
+
+/*
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in arch_init_sched_domains.
+ */
+static void rebalance_domains(int cpu, enum cpu_idle_type idle)
+{
+       int balance = 1;
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long interval;
+       struct sched_domain *sd;
+       /* Earliest time when we have to do rebalance again */
+       unsigned long next_balance = jiffies + 60*HZ;
+       int update_next_balance = 0;
+       int need_serialize;
+       cpumask_t tmp;
+
+       for_each_domain(cpu, sd) {
+               if (!(sd->flags & SD_LOAD_BALANCE))
+                       continue;
+
+               interval = sd->balance_interval;
+               if (idle != CPU_IDLE)
+                       interval *= sd->busy_factor;
+
+               /* scale ms to jiffies */
+               interval = msecs_to_jiffies(interval);
+               if (unlikely(!interval))
+                       interval = 1;
+               if (interval > HZ*NR_CPUS/10)
+                       interval = HZ*NR_CPUS/10;
+
+               need_serialize = sd->flags & SD_SERIALIZE;
+
+               if (need_serialize) {
+                       if (!spin_trylock(&balancing))
+                               goto out;
+               }
+
+               if (time_after_eq(jiffies, sd->last_balance + interval)) {
+                       if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) {
+                               /*
+                                * We've pulled tasks over so either we're no
+                                * longer idle, or one of our SMT siblings is
+                                * not idle.
+                                */
+                               idle = CPU_NOT_IDLE;
+                       }
+                       sd->last_balance = jiffies;
+               }
+               if (need_serialize)
+                       spin_unlock(&balancing);
+out:
+               if (time_after(next_balance, sd->last_balance + interval)) {
+                       next_balance = sd->last_balance + interval;
+                       update_next_balance = 1;
+               }
+
+               /*
+                * Stop the load balance at this level. There is another
+                * CPU in our sched group which is doing load balancing more
+                * actively.
+                */
+               if (!balance)
+                       break;
+       }
+
+       /*
+        * next_balance will be updated only when there is a need.
+        * When the cpu is attached to null domain for ex, it will not be
+        * updated.
+        */
+       if (likely(update_next_balance))
+               rq->next_balance = next_balance;
+}
+
+/*
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * In CONFIG_NO_HZ case, the idle load balance owner will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
+ */
+static void run_rebalance_domains(struct softirq_action *h)
+{
+       int this_cpu = smp_processor_id();
+       struct rq *this_rq = cpu_rq(this_cpu);
+       enum cpu_idle_type idle = this_rq->idle_at_tick ?
+                                               CPU_IDLE : CPU_NOT_IDLE;
+
+       rebalance_domains(this_cpu, idle);
+
+#ifdef CONFIG_NO_HZ
+       /*
+        * If this cpu is the owner for idle load balancing, then do the
+        * balancing on behalf of the other idle cpus whose ticks are
+        * stopped.
+        */
+       if (this_rq->idle_at_tick &&
+           atomic_read(&nohz.load_balancer) == this_cpu) {
+               cpumask_t cpus = nohz.cpu_mask;
+               struct rq *rq;
+               int balance_cpu;
+
+               cpu_clear(this_cpu, cpus);
+               for_each_cpu_mask_nr(balance_cpu, cpus) {
+                       /*
+                        * If this cpu gets work to do, stop the load balancing
+                        * work being done for other cpus. Next load
+                        * balancing owner will pick it up.
+                        */
+                       if (need_resched())
+                               break;
+
+                       rebalance_domains(balance_cpu, CPU_IDLE);
+
+                       rq = cpu_rq(balance_cpu);
+                       if (time_after(this_rq->next_balance, rq->next_balance))
+                               this_rq->next_balance = rq->next_balance;
+               }
+       }
+#endif
+}
+
+/*
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ *
+ * In case of CONFIG_NO_HZ, this is the place where we nominate a new
+ * idle load balancing owner or decide to stop the periodic load balancing,
+ * if the whole system is idle.
+ */
+static inline void trigger_load_balance(struct rq *rq, int cpu)
+{
+#ifdef CONFIG_NO_HZ
+       /*
+        * If we were in the nohz mode recently and busy at the current
+        * scheduler tick, then check if we need to nominate new idle
+        * load balancer.
+        */
+       if (rq->in_nohz_recently && !rq->idle_at_tick) {
+               rq->in_nohz_recently = 0;
+
+               if (atomic_read(&nohz.load_balancer) == cpu) {
+                       cpu_clear(cpu, nohz.cpu_mask);
+                       atomic_set(&nohz.load_balancer, -1);
+               }
+
+               if (atomic_read(&nohz.load_balancer) == -1) {
+                       /*
+                        * simple selection for now: Nominate the
+                        * first cpu in the nohz list to be the next
+                        * ilb owner.
+                        *
+                        * TBD: Traverse the sched domains and nominate
+                        * the nearest cpu in the nohz.cpu_mask.
+                        */
+                       int ilb = first_cpu(nohz.cpu_mask);
+
+                       if (ilb < nr_cpu_ids)
+                               resched_cpu(ilb);
+               }
+       }
+
+       /*
+        * If this cpu is idle and doing idle load balancing for all the
+        * cpus with ticks stopped, is it time for that to stop?
+        */
+       if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
+           cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+               resched_cpu(cpu);
+               return;
+       }
+
+       /*
+        * If this cpu is idle and the idle load balancing is done by
+        * someone else, then no need raise the SCHED_SOFTIRQ
+        */
+       if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
+           cpu_isset(cpu, nohz.cpu_mask))
+               return;
+#endif
+       if (time_after_eq(jiffies, rq->next_balance))
+               raise_softirq(SCHED_SOFTIRQ);
+}
+
+#else  /* CONFIG_SMP */
+
+/*
+ * on UP we do not need to balance between CPUs:
+ */
+static inline void idle_balance(int cpu, struct rq *rq)
+{
+}
+
+#endif
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+
+/*
+ * Return p->sum_exec_runtime plus any more ns on the sched_clock
+ * that have not yet been banked in case the task is currently running.
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+       unsigned long flags;
+       u64 ns, delta_exec;
+       struct rq *rq;
+
+       rq = task_rq_lock(p, &flags);
+       ns = p->se.sum_exec_runtime;
+       if (task_current(rq, p)) {
+               update_rq_clock(rq);
+               delta_exec = rq->clock - p->se.exec_start;
+               if ((s64)delta_exec > 0)
+                       ns += delta_exec;
+       }
+       task_rq_unlock(rq, &flags);
+
+       return ns;
+}
+
+/*
+ * Account user cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in user space since the last update
+ */
+void account_user_time(struct task_struct *p, cputime_t cputime)
+{
+       struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+       struct vx_info *vxi = p->vx_info;  /* p is _always_ current */
+       cputime64_t tmp;
+       int nice = (TASK_NICE(p) > 0);
+
+       p->utime = cputime_add(p->utime, cputime);
+       vx_account_user(vxi, cputime, nice);
+
+       /* Add user time to cpustat. */
+       tmp = cputime_to_cputime64(cputime);
+       if (nice)
+               cpustat->nice = cputime64_add(cpustat->nice, tmp);
+       else
+               cpustat->user = cputime64_add(cpustat->user, tmp);
+       /* Account for user time used */
+       acct_update_integrals(p);
+}
+
+/*
+ * Account guest cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in virtual machine since the last update
+ */
+static void account_guest_time(struct task_struct *p, cputime_t cputime)
+{
+       cputime64_t tmp;
+       struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+
+       tmp = cputime_to_cputime64(cputime);
+
+       p->utime = cputime_add(p->utime, cputime);
+       p->gtime = cputime_add(p->gtime, cputime);
+
+       cpustat->user = cputime64_add(cpustat->user, tmp);
+       cpustat->guest = cputime64_add(cpustat->guest, tmp);
+}
+
+/*
+ * Account scaled user cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in user space since the last update
+ */
+void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
+{
+       p->utimescaled = cputime_add(p->utimescaled, cputime);
+}
+
+/*
+ * Account system cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @hardirq_offset: the offset to subtract from hardirq_count()
+ * @cputime: the cpu time spent in kernel space since the last update
+ */
+void account_system_time(struct task_struct *p, int hardirq_offset,
+                        cputime_t cputime)
+{
+       struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+       struct vx_info *vxi = p->vx_info;  /* p is _always_ current */
+       struct rq *rq = this_rq();
+       cputime64_t tmp;
+
+       if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
+               account_guest_time(p, cputime);
+               return;
+       }
+
+       p->stime = cputime_add(p->stime, cputime);
+       vx_account_system(vxi, cputime, (p == rq->idle));
+
+       /* Add system time to cpustat. */
+       tmp = cputime_to_cputime64(cputime);
+       if (hardirq_count() - hardirq_offset)
+               cpustat->irq = cputime64_add(cpustat->irq, tmp);
+       else if (softirq_count())
+               cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+       else if (p != rq->idle)
+               cpustat->system = cputime64_add(cpustat->system, tmp);
+       else if (atomic_read(&rq->nr_iowait) > 0)
+               cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
+       else
+               cpustat->idle = cputime64_add(cpustat->idle, tmp);
+       /* Account for system time used */
+       acct_update_integrals(p);
+}
+
+/*
+ * Account scaled system cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @hardirq_offset: the offset to subtract from hardirq_count()
+ * @cputime: the cpu time spent in kernel space since the last update
+ */
+void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
+{
+       p->stimescaled = cputime_add(p->stimescaled, cputime);
+}
+
+/*
+ * Account for involuntary wait time.
+ * @p: the process from which the cpu time has been stolen
+ * @steal: the cpu time spent in involuntary wait
+ */
+void account_steal_time(struct task_struct *p, cputime_t steal)
+{
+       struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+       cputime64_t tmp = cputime_to_cputime64(steal);
+       struct rq *rq = this_rq();
+
+       if (p == rq->idle) {
+               p->stime = cputime_add(p->stime, steal);
+               if (atomic_read(&rq->nr_iowait) > 0)
+                       cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
+               else
+                       cpustat->idle = cputime64_add(cpustat->idle, tmp);
+       } else
+               cpustat->steal = cputime64_add(cpustat->steal, tmp);
+}
+
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+cputime_t task_utime(struct task_struct *p)
+{
+       return p->utime;
+}
+
+cputime_t task_stime(struct task_struct *p)
+{
+       return p->stime;
+}
+#else
+cputime_t task_utime(struct task_struct *p)
+{
+       clock_t utime = cputime_to_clock_t(p->utime),
+               total = utime + cputime_to_clock_t(p->stime);
+       u64 temp;
+
+       /*
+        * Use CFS's precise accounting:
+        */
+       temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
+
+       if (total) {
+               temp *= utime;
+               do_div(temp, total);
+       }
+       utime = (clock_t)temp;
+
+       p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
+       return p->prev_utime;
+}
+
+cputime_t task_stime(struct task_struct *p)
+{
+       clock_t stime;
+
+       /*
+        * Use CFS's precise accounting. (we subtract utime from
+        * the total, to make sure the total observed by userspace
+        * grows monotonically - apps rely on that):
+        */
+       stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
+                       cputime_to_clock_t(task_utime(p));
+
+       if (stime >= 0)
+               p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
+
+       return p->prev_stime;
+}
+#endif
+
+inline cputime_t task_gtime(struct task_struct *p)
+{
+       return p->gtime;
+}
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled.
+ *
+ * It also gets called by the fork code, when changing the parent's
+ * timeslices.
+ */
+void scheduler_tick(void)
+{
+       int cpu = smp_processor_id();
+       struct rq *rq = cpu_rq(cpu);
+       struct task_struct *curr = rq->curr;
+
+       sched_clock_tick();
+
+       spin_lock(&rq->lock);
+       update_rq_clock(rq);
+       update_cpu_load(rq);
+       curr->sched_class->task_tick(rq, curr, 0);
+       spin_unlock(&rq->lock);
+
+#ifdef CONFIG_SMP
+       rq->idle_at_tick = idle_cpu(cpu);
+       trigger_load_balance(rq, cpu);
+#endif
+}
+
+#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
+                               defined(CONFIG_PREEMPT_TRACER))
+
+static inline unsigned long get_parent_ip(unsigned long addr)
+{
+       if (in_lock_functions(addr)) {
+               addr = CALLER_ADDR2;
+               if (in_lock_functions(addr))
+                       addr = CALLER_ADDR3;
+       }
+       return addr;
+}
+
+void __kprobes add_preempt_count(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+       /*
+        * Underflow?
+        */
+       if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+               return;
+#endif
+       preempt_count() += val;
+#ifdef CONFIG_DEBUG_PREEMPT
+       /*
+        * Spinlock count overflowing soon?
+        */
+       DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
+                               PREEMPT_MASK - 10);
+#endif
+       if (preempt_count() == val)
+               trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+}
+EXPORT_SYMBOL(add_preempt_count);
+
+void __kprobes sub_preempt_count(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+       /*
+        * Underflow?
+        */
+       if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+               return;
+       /*
+        * Is the spinlock portion underflowing?
+        */
+       if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+                       !(preempt_count() & PREEMPT_MASK)))
+               return;
+#endif
+
+       if (preempt_count() == val)
+               trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+       preempt_count() -= val;
+}
+EXPORT_SYMBOL(sub_preempt_count);
+
+#endif
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+       struct pt_regs *regs = get_irq_regs();
+
+       printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+               prev->comm, prev->pid, preempt_count());
+
+       debug_show_held_locks(prev);
+       print_modules();
+       if (irqs_disabled())
+               print_irqtrace_events(prev);
+
+       if (regs)
+               show_regs(regs);
+       else
+               dump_stack();
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev)
+{
+       /*
+        * Test if we are atomic. Since do_exit() needs to call into
+        * schedule() atomically, we ignore that path for now.
+        * Otherwise, whine if we are scheduling when we should not be.
+        */
+       if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
+               __schedule_bug(prev);
+
+       profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+       schedstat_inc(this_rq(), sched_count);
+#ifdef CONFIG_SCHEDSTATS
+       if (unlikely(prev->lock_depth >= 0)) {
+               schedstat_inc(this_rq(), bkl_count);
+               schedstat_inc(prev, sched_info.bkl_count);
+       }
+#endif
+}
+
+/*
+ * Pick up the highest-prio task:
+ */
+static inline struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev)
+{
+       const struct sched_class *class;
+       struct task_struct *p;
+
+       /*
+        * Optimization: we know that if all tasks are in
+        * the fair class we can call that function directly:
+        */
+       if (likely(rq->nr_running == rq->cfs.nr_running)) {
+               p = fair_sched_class.pick_next_task(rq);
+               if (likely(p))
+                       return p;
+       }
+
+       class = sched_class_highest;
+       for ( ; ; ) {
+               p = class->pick_next_task(rq);
+               if (p)
+                       return p;
+               /*
+                * Will never be NULL as the idle class always
+                * returns a non-NULL p:
+                */
+               class = class->next;
+       }
+}
+
+void (*rec_event)(void *,unsigned int) = NULL;
+EXPORT_SYMBOL(rec_event);
+#ifdef CONFIG_CHOPSTIX
+
+struct event_spec {
+    unsigned long pc;
+    unsigned long dcookie;
+    unsigned int count;
+    unsigned int reason;
+};
+
+/* To support safe calling from asm */
+asmlinkage void rec_event_asm (struct event *event_signature_in, unsigned int count) {
+    struct pt_regs *regs;
+    struct event_spec *es = event_signature_in->event_data;
+    regs = task_pt_regs(current);
+    event_signature_in->task=current;
+    es->pc=regs->ip;
+    event_signature_in->count=1;
+    (*rec_event)(event_signature_in, count);
+}
+#endif
+
+/*
+ * schedule() is the main scheduler function.
+ */
+asmlinkage void __sched schedule(void)
+{
+       struct task_struct *prev, *next;
+       unsigned long *switch_count;
+       struct rq *rq;
+       int cpu;
+
+need_resched:
+       preempt_disable();
+       cpu = smp_processor_id();
+       rq = cpu_rq(cpu);
+       rcu_qsctr_inc(cpu);
+       prev = rq->curr;
+       switch_count = &prev->nivcsw;
+
+       release_kernel_lock(prev);
+need_resched_nonpreemptible:
+
+       schedule_debug(prev);
+
+       if (sched_feat(HRTICK))
+               hrtick_clear(rq);
+
+       /*
+        * Do the rq-clock update outside the rq lock:
+        */
+       local_irq_disable();
+       update_rq_clock(rq);
+       spin_lock(&rq->lock);
+       clear_tsk_need_resched(prev);
+
+       if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+               if (unlikely(signal_pending_state(prev->state, prev)))
+                       prev->state = TASK_RUNNING;
+               else
+                       deactivate_task(rq, prev, 1);
+               switch_count = &prev->nvcsw;
+       }
+
+#ifdef CONFIG_SMP
+       if (prev->sched_class->pre_schedule)
+               prev->sched_class->pre_schedule(rq, prev);
+#endif
+
+       if (unlikely(!rq->nr_running))
+               idle_balance(cpu, rq);
+
+       prev->sched_class->put_prev_task(rq, prev);
+       next = pick_next_task(rq, prev);
+
+       if (likely(prev != next)) {
+               sched_info_switch(prev, next);
+
+               rq->nr_switches++;
+               rq->curr = next;
+               ++*switch_count;
+
+               context_switch(rq, prev, next); /* unlocks the rq */
+               /*
+                * the context switch might have flipped the stack from under
+                * us, hence refresh the local variables.
+                */
+               cpu = smp_processor_id();
+               rq = cpu_rq(cpu);
+       } else
+               spin_unlock_irq(&rq->lock);
+
+       if (unlikely(reacquire_kernel_lock(current) < 0))
+               goto need_resched_nonpreemptible;
+
+       preempt_enable_no_resched();
+       if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+               goto need_resched;
+}
+EXPORT_SYMBOL(schedule);
+
+#ifdef CONFIG_PREEMPT
+/*
+ * this is the entry point to schedule() from in-kernel preemption
+ * off of preempt_enable. Kernel preemptions off return from interrupt
+ * occur there and call schedule directly.
+ */
+asmlinkage void __sched preempt_schedule(void)
+{
+       struct thread_info *ti = current_thread_info();
+
+       /*
+        * If there is a non-zero preempt_count or interrupts are disabled,
+        * we do not want to preempt the current task. Just return..
+        */
+       if (likely(ti->preempt_count || irqs_disabled()))
+               return;
+
+       do {
+               add_preempt_count(PREEMPT_ACTIVE);
+               schedule();
+               sub_preempt_count(PREEMPT_ACTIVE);
+
+               /*
+                * Check again in case we missed a preemption opportunity
+                * between schedule and now.
+                */
+               barrier();
+       } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+}
+EXPORT_SYMBOL(preempt_schedule);
+
+/*
+ * this is the entry point to schedule() from kernel preemption
+ * off of irq context.
+ * Note, that this is called and return with irqs disabled. This will
+ * protect us against recursive calling from irq.
+ */
+asmlinkage void __sched preempt_schedule_irq(void)
+{
+       struct thread_info *ti = current_thread_info();
+
+       /* Catch callers which need to be fixed */
+       BUG_ON(ti->preempt_count || !irqs_disabled());
+
+       do {
+               add_preempt_count(PREEMPT_ACTIVE);
+               local_irq_enable();
+               schedule();
+               local_irq_disable();
+               sub_preempt_count(PREEMPT_ACTIVE);
+
+               /*
+                * Check again in case we missed a preemption opportunity
+                * between schedule and now.
+                */
+               barrier();
+       } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+}
+
+#endif /* CONFIG_PREEMPT */
+
+int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
+                         void *key)
+{
+       return try_to_wake_up(curr->private, mode, sync);
+}
+EXPORT_SYMBOL(default_wake_function);
+
+/*
+ * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
+ * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
+ * number) then we wake all the non-exclusive tasks and one exclusive task.
+ *
+ * There are circumstances in which we can try to wake a task which has already
+ * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
+ * zero in this (rare) case, and we handle it by continuing to scan the queue.
+ */
+static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
+                            int nr_exclusive, int sync, void *key)
+{
+       wait_queue_t *curr, *next;
+
+       list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
+               unsigned flags = curr->flags;
+
+               if (curr->func(curr, mode, sync, key) &&
+                               (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
+                       break;
+       }
+}
+
+/**
+ * __wake_up - wake up threads blocked on a waitqueue.
+ * @q: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: is directly passed to the wakeup function
+ */
+void __wake_up(wait_queue_head_t *q, unsigned int mode,
+                       int nr_exclusive, void *key)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&q->lock, flags);
+       __wake_up_common(q, mode, nr_exclusive, 0, key);
+       spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(__wake_up);
+
+/*
+ * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
+ */
+void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
+{
+       __wake_up_common(q, mode, 1, 0, NULL);
+}
+
+/**
+ * __wake_up_sync - wake up threads blocked on a waitqueue.
+ * @q: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ *
+ * The sync wakeup differs that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ */
+void
+__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+{
+       unsigned long flags;
+       int sync = 1;
+
+       if (unlikely(!q))
+               return;
+
+       if (unlikely(!nr_exclusive))
+               sync = 0;
+
+       spin_lock_irqsave(&q->lock, flags);
+       __wake_up_common(q, mode, nr_exclusive, sync, NULL);
+       spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync);     /* For internal use only */
+
+void complete(struct completion *x)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&x->wait.lock, flags);
+       x->done++;
+       __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
+       spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete);
+
+void complete_all(struct completion *x)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&x->wait.lock, flags);
+       x->done += UINT_MAX/2;
+       __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
+       spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete_all);
+
+static inline long __sched
+do_wait_for_common(struct completion *x, long timeout, int state)
+{
+       if (!x->done) {
+               DECLARE_WAITQUEUE(wait, current);
+
+               wait.flags |= WQ_FLAG_EXCLUSIVE;
+               __add_wait_queue_tail(&x->wait, &wait);
+               do {
+                       if ((state == TASK_INTERRUPTIBLE &&
+                            signal_pending(current)) ||
+                           (state == TASK_KILLABLE &&
+                            fatal_signal_pending(current))) {
+                               timeout = -ERESTARTSYS;
+                               break;
+                       }
+                       __set_current_state(state);
+                       spin_unlock_irq(&x->wait.lock);
+                       timeout = schedule_timeout(timeout);
+                       spin_lock_irq(&x->wait.lock);
+               } while (!x->done && timeout);
+               __remove_wait_queue(&x->wait, &wait);
+               if (!x->done)
+                       return timeout;
+       }
+       x->done--;
+       return timeout ?: 1;
+}
+
+static long __sched
+wait_for_common(struct completion *x, long timeout, int state)
+{
+       might_sleep();
+
+       spin_lock_irq(&x->wait.lock);
+       timeout = do_wait_for_common(x, timeout, state);
+       spin_unlock_irq(&x->wait.lock);
+       return timeout;
+}
+
+void __sched wait_for_completion(struct completion *x)
+{
+       wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion);
+
+unsigned long __sched
+wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+       return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_timeout);
+
+int __sched wait_for_completion_interruptible(struct completion *x)
+{
+       long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
+       if (t == -ERESTARTSYS)
+               return t;
+       return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible);
+
+unsigned long __sched
+wait_for_completion_interruptible_timeout(struct completion *x,
+                                         unsigned long timeout)
+{
+       return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+
+int __sched wait_for_completion_killable(struct completion *x)
+{
+       long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
+       if (t == -ERESTARTSYS)
+               return t;
+       return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_killable);
+
+/**
+ *     try_wait_for_completion - try to decrement a completion without blocking
+ *     @x:     completion structure
+ *
+ *     Returns: 0 if a decrement cannot be done without blocking
+ *              1 if a decrement succeeded.
+ *
+ *     If a completion is being used as a counting completion,
+ *     attempt to decrement the counter without blocking. This
+ *     enables us to avoid waiting if the resource the completion
+ *     is protecting is not available.
+ */
+bool try_wait_for_completion(struct completion *x)
+{
+       int ret = 1;
+
+       spin_lock_irq(&x->wait.lock);
+       if (!x->done)
+               ret = 0;
+       else
+               x->done--;
+       spin_unlock_irq(&x->wait.lock);
+       return ret;
+}
+EXPORT_SYMBOL(try_wait_for_completion);
+
+/**
+ *     completion_done - Test to see if a completion has any waiters
+ *     @x:     completion structure
+ *
+ *     Returns: 0 if there are waiters (wait_for_completion() in progress)
+ *              1 if there are no waiters.
+ *
+ */
+bool completion_done(struct completion *x)
+{
+       int ret = 1;
+
+       spin_lock_irq(&x->wait.lock);
+       if (!x->done)
+               ret = 0;
+       spin_unlock_irq(&x->wait.lock);
+       return ret;
+}
+EXPORT_SYMBOL(completion_done);
+
+static long __sched
+sleep_on_common(wait_queue_head_t *q, int state, long timeout)
+{
+       unsigned long flags;
+       wait_queue_t wait;
+
+       init_waitqueue_entry(&wait, current);
+
+       __set_current_state(state);
+
+       spin_lock_irqsave(&q->lock, flags);
+       __add_wait_queue(q, &wait);
+       spin_unlock(&q->lock);
+       timeout = schedule_timeout(timeout);
+       spin_lock_irq(&q->lock);
+       __remove_wait_queue(q, &wait);
+       spin_unlock_irqrestore(&q->lock, flags);
+
+       return timeout;
+}
+
+void __sched interruptible_sleep_on(wait_queue_head_t *q)
+{
+       sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+}
+EXPORT_SYMBOL(interruptible_sleep_on);
+
+long __sched
+interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
+{
+       return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
+}
+EXPORT_SYMBOL(interruptible_sleep_on_timeout);
+
+void __sched sleep_on(wait_queue_head_t *q)
+{
+       sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+}
+EXPORT_SYMBOL(sleep_on);
+
+long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
+{
+       return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
+}
+EXPORT_SYMBOL(sleep_on_timeout);
+
+#ifdef CONFIG_RT_MUTEXES
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task
+ * @prio: prio value (kernel-internal form)
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance logic.
+ */
+void rt_mutex_setprio(struct task_struct *p, int prio)
+{
+       unsigned long flags;
+       int oldprio, on_rq, running;
+       struct rq *rq;
+       const struct sched_class *prev_class = p->sched_class;
+
+       BUG_ON(prio < 0 || prio > MAX_PRIO);
+
+       rq = task_rq_lock(p, &flags);
+       update_rq_clock(rq);
+
+       oldprio = p->prio;
+       on_rq = p->se.on_rq;
+       running = task_current(rq, p);
+       if (on_rq)
+               dequeue_task(rq, p, 0);
+       if (running)
+               p->sched_class->put_prev_task(rq, p);
+
+       if (rt_prio(prio))
+               p->sched_class = &rt_sched_class;
+       else
+               p->sched_class = &fair_sched_class;
+
+       p->prio = prio;
+
+       if (running)
+               p->sched_class->set_curr_task(rq);
+       if (on_rq) {
+               enqueue_task(rq, p, 0);
+
+               check_class_changed(rq, p, prev_class, oldprio, running);
+       }
+       task_rq_unlock(rq, &flags);
+}
+
+#endif
+
+void set_user_nice(struct task_struct *p, long nice)
+{
+       int old_prio, delta, on_rq;
+       unsigned long flags;
+       struct rq *rq;
+
+       if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
+               return;
+       /*
+        * We have to be careful, if called from sys_setpriority(),
+        * the task might be in the middle of scheduling on another CPU.
+        */
+       rq = task_rq_lock(p, &flags);
+       update_rq_clock(rq);
+       /*
+        * The RT priorities are set via sched_setscheduler(), but we still
+        * allow the 'normal' nice value to be set - but as expected
+        * it wont have any effect on scheduling until the task is
+        * SCHED_FIFO/SCHED_RR:
+        */
+       if (task_has_rt_policy(p)) {
+               p->static_prio = NICE_TO_PRIO(nice);
+               goto out_unlock;
+       }
+       on_rq = p->se.on_rq;
+       if (on_rq)
+               dequeue_task(rq, p, 0);
+
+       p->static_prio = NICE_TO_PRIO(nice);
+       set_load_weight(p);
+       old_prio = p->prio;
+       p->prio = effective_prio(p);
+       delta = p->prio - old_prio;
+
+       if (on_rq) {
+               enqueue_task(rq, p, 0);
+               /*
+                * If the task increased its priority or is running and
+                * lowered its priority, then reschedule its CPU:
+                */
+               if (delta < 0 || (delta > 0 && task_running(rq, p)))
+                       resched_task(rq->curr);
+       }
+out_unlock:
+       task_rq_unlock(rq, &flags);
+}
+EXPORT_SYMBOL(set_user_nice);
+
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const struct task_struct *p, const int nice)
+{
+       /* convert nice value [19,-20] to rlimit style value [1,40] */
+       int nice_rlim = 20 - nice;
+
+       return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
+               capable(CAP_SYS_NICE));
+}
+
+#ifdef __ARCH_WANT_SYS_NICE
+
+/*
+ * sys_nice - change the priority of the current process.
+ * @increment: priority increment
+ *
+ * sys_setpriority is a more generic, but much slower function that
+ * does similar things.
+ */
+SYSCALL_DEFINE1(nice, int, increment)
+{
+       long nice, retval;
+
+       /*
+        * Setpriority might change our priority at the same moment.
+        * We don't have to worry. Conceptually one call occurs first
+        * and we have a single winner.
+        */
+       if (increment < -40)
+               increment = -40;
+       if (increment > 40)
+               increment = 40;
+
+       nice = PRIO_TO_NICE(current->static_prio) + increment;
+       if (nice < -20)
+               nice = -20;
+       if (nice > 19)
+               nice = 19;
+
+       if (increment < 0 && !can_nice(current, nice))
+               return vx_flags(VXF_IGNEG_NICE, 0) ? 0 : -EPERM;
+
+       retval = security_task_setnice(current, nice);
+       if (retval)
+               return retval;
+
+       set_user_nice(current, nice);
+       return 0;
+}
+
+#endif
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * This is the priority value as seen by users in /proc.
+ * RT tasks are offset by -200. Normal tasks are centered
+ * around 0, value goes from -16 to +15.
+ */
+int task_prio(const struct task_struct *p)
+{
+       return p->prio - MAX_RT_PRIO;
+}
+
+/**
+ * task_nice - return the nice value of a given task.
+ * @p: the task in question.
+ */
+int task_nice(const struct task_struct *p)
+{
+       return TASK_NICE(p);
+}
+EXPORT_SYMBOL(task_nice);
+
+/**
+ * idle_cpu - is a given cpu idle currently?
+ * @cpu: the processor in question.
+ */
+int idle_cpu(int cpu)
+{
+       return cpu_curr(cpu) == cpu_rq(cpu)->idle;
+}
+
+/**
+ * idle_task - return the idle task for a given cpu.
+ * @cpu: the processor in question.
+ */
+struct task_struct *idle_task(int cpu)
+{
+       return cpu_rq(cpu)->idle;
+}
+
+/**
+ * find_process_by_pid - find a process with a matching PID value.
+ * @pid: the pid in question.
+ */
+static struct task_struct *find_process_by_pid(pid_t pid)
+{
+       return pid ? find_task_by_vpid(pid) : current;
+}
+
+/* Actually do priority change: must hold rq lock. */
+static void
+__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
+{
+       BUG_ON(p->se.on_rq);
+
+       p->policy = policy;
+       switch (p->policy) {
+       case SCHED_NORMAL:
+       case SCHED_BATCH:
+       case SCHED_IDLE:
+               p->sched_class = &fair_sched_class;
+               break;
+       case SCHED_FIFO:
+       case SCHED_RR:
+               p->sched_class = &rt_sched_class;
+               break;
+       }
+
+       p->rt_priority = prio;
+       p->normal_prio = normal_prio(p);
+       /* we are holding p->pi_lock already */
+       p->prio = rt_mutex_getprio(p);
+       set_load_weight(p);
+}
+
+static int __sched_setscheduler(struct task_struct *p, int policy,
+                               struct sched_param *param, bool user)
+{
+       int retval, oldprio, oldpolicy = -1, on_rq, running;
+       unsigned long flags;
+       const struct sched_class *prev_class = p->sched_class;
+       struct rq *rq;
+
+       /* may grab non-irq protected spin_locks */
+       BUG_ON(in_interrupt());
+recheck:
+       /* double check policy once rq lock held */
+       if (policy < 0)
+               policy = oldpolicy = p->policy;
+       else if (policy != SCHED_FIFO && policy != SCHED_RR &&
+                       policy != SCHED_NORMAL && policy != SCHED_BATCH &&
+                       policy != SCHED_IDLE)
+               return -EINVAL;
+       /*
+        * Valid priorities for SCHED_FIFO and SCHED_RR are
+        * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
+        * SCHED_BATCH and SCHED_IDLE is 0.
+        */
+       if (param->sched_priority < 0 ||
+           (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
+           (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
+               return -EINVAL;
+       if (rt_policy(policy) != (param->sched_priority != 0))
+               return -EINVAL;
+
+       /*
+        * Allow unprivileged RT tasks to decrease priority:
+        */
+       if (user && !capable(CAP_SYS_NICE)) {
+               if (rt_policy(policy)) {
+                       unsigned long rlim_rtprio;
+
+                       if (!lock_task_sighand(p, &flags))
+                               return -ESRCH;
+                       rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
+                       unlock_task_sighand(p, &flags);
+
+                       /* can't set/change the rt policy */
+                       if (policy != p->policy && !rlim_rtprio)
+                               return -EPERM;
+
+                       /* can't increase priority */
+                       if (param->sched_priority > p->rt_priority &&
+                           param->sched_priority > rlim_rtprio)
+                               return -EPERM;
+               }
+               /*
+                * Like positive nice levels, dont allow tasks to
+                * move out of SCHED_IDLE either:
+                */
+               if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
+                       return -EPERM;
+
+               /* can't change other user's priorities */
+               if ((current->euid != p->euid) &&
+                   (current->euid != p->uid))
+                       return -EPERM;
+       }
+
+       if (user) {
+#ifdef CONFIG_RT_GROUP_SCHED
+               /*
+                * Do not allow realtime tasks into groups that have no runtime
+                * assigned.
+                */
+               if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
+                       return -EPERM;
+#endif
+
+               retval = security_task_setscheduler(p, policy, param);
+               if (retval)
+                       return retval;
+       }
+
+       /*
+        * make sure no PI-waiters arrive (or leave) while we are
+        * changing the priority of the task:
+        */
+       spin_lock_irqsave(&p->pi_lock, flags);
+       /*
+        * To be able to change p->policy safely, the apropriate
+        * runqueue lock must be held.
+        */
+       rq = __task_rq_lock(p);
+       /* recheck policy now with rq lock held */
+       if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+               policy = oldpolicy = -1;
+               __task_rq_unlock(rq);
+               spin_unlock_irqrestore(&p->pi_lock, flags);
+               goto recheck;
+       }
+       update_rq_clock(rq);
+       on_rq = p->se.on_rq;
+       running = task_current(rq, p);
+       if (on_rq)
+               deactivate_task(rq, p, 0);
+       if (running)
+               p->sched_class->put_prev_task(rq, p);
+
+       oldprio = p->prio;
+       __setscheduler(rq, p, policy, param->sched_priority);
+
+       if (running)
+               p->sched_class->set_curr_task(rq);
+       if (on_rq) {
+               activate_task(rq, p, 0);
+
+               check_class_changed(rq, p, prev_class, oldprio, running);
+       }
+       __task_rq_unlock(rq);
+       spin_unlock_irqrestore(&p->pi_lock, flags);
+
+       rt_mutex_adjust_pi(p);
+
+       return 0;
+}
+
+/**
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * NOTE that the task may be already dead.
+ */
+int sched_setscheduler(struct task_struct *p, int policy,
+                      struct sched_param *param)
+{
+       return __sched_setscheduler(p, policy, param, true);
+}
+EXPORT_SYMBOL_GPL(sched_setscheduler);
+
+/**
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Just like sched_setscheduler, only don't bother checking if the
+ * current context has permission.  For example, this is needed in
+ * stop_machine(): we create temporary high priority worker threads,
+ * but our caller might not have that capability.
+ */
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
+                              struct sched_param *param)
+{
+       return __sched_setscheduler(p, policy, param, false);
+}
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+       struct sched_param lparam;
+       struct task_struct *p;
+       int retval;
+
+       if (!param || pid < 0)
+               return -EINVAL;
+       if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+               return -EFAULT;
+
+       rcu_read_lock();
+       retval = -ESRCH;
+       p = find_process_by_pid(pid);
+       if (p != NULL)
+               retval = sched_setscheduler(p, policy, &lparam);
+       rcu_read_unlock();
+
+       return retval;
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ */
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
+               struct sched_param __user *, param)
+{
+       /* negative values for policy are not valid */
+       if (policy < 0)
+               return -EINVAL;
+
+       return do_sched_setscheduler(pid, policy, param);
+}
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ */
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
+{
+       return do_sched_setscheduler(pid, -1, param);
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ */
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
+{
+       struct task_struct *p;
+       int retval;
+
+       if (pid < 0)
+               return -EINVAL;
+
+       retval = -ESRCH;
+       read_lock(&tasklist_lock);
+       p = find_process_by_pid(pid);
+       if (p) {
+               retval = security_task_getscheduler(p);
+               if (!retval)
+                       retval = p->policy;
+       }
+       read_unlock(&tasklist_lock);
+       return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the RT priority.
+ */
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
+{
+       struct sched_param lp;
+       struct task_struct *p;
+       int retval;
+
+       if (!param || pid < 0)
+               return -EINVAL;
+
+       read_lock(&tasklist_lock);
+       p = find_process_by_pid(pid);
+       retval = -ESRCH;
+       if (!p)
+               goto out_unlock;
+
+       retval = security_task_getscheduler(p);
+       if (retval)
+               goto out_unlock;
+
+       lp.sched_priority = p->rt_priority;
+       read_unlock(&tasklist_lock);
+
+       /*
+        * This one might sleep, we cannot do it with a spinlock held ...
+        */
+       retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
+
+       return retval;
+
+out_unlock:
+       read_unlock(&tasklist_lock);
+       return retval;
+}
+
+long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
+{
+       cpumask_t cpus_allowed;
+       cpumask_t new_mask = *in_mask;
+       struct task_struct *p;
+       int retval;
+
+       get_online_cpus();
+       read_lock(&tasklist_lock);
+
+       p = find_process_by_pid(pid);
+       if (!p) {
+               read_unlock(&tasklist_lock);
+               put_online_cpus();
+               return -ESRCH;
+       }
+
+       /*
+        * It is not safe to call set_cpus_allowed with the
+        * tasklist_lock held. We will bump the task_struct's
+        * usage count and then drop tasklist_lock.
+        */
+       get_task_struct(p);
+       read_unlock(&tasklist_lock);
+
+
+       retval = -EPERM;
+       if ((current->euid != p->euid) && (current->euid != p->uid) &&
+                       !capable(CAP_SYS_NICE))
+               goto out_unlock;
+
+       retval = security_task_setscheduler(p, 0, NULL);
+       if (retval)
+               goto out_unlock;
+
+       cpuset_cpus_allowed(p, &cpus_allowed);
+       cpus_and(new_mask, new_mask, cpus_allowed);
+ again:
+       retval = set_cpus_allowed_ptr(p, &new_mask);
+
+       if (!retval) {
+               cpuset_cpus_allowed(p, &cpus_allowed);
+               if (!cpus_subset(new_mask, cpus_allowed)) {
+                       /*
+                        * We must have raced with a concurrent cpuset
+                        * update. Just reset the cpus_allowed to the
+                        * cpuset's cpus_allowed
+                        */
+                       new_mask = cpus_allowed;
+                       goto again;
+               }
+       }
+out_unlock:
+       put_task_struct(p);
+       put_online_cpus();
+       return retval;
+}
+
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
+                            cpumask_t *new_mask)
+{
+       if (len < sizeof(cpumask_t)) {
+               memset(new_mask, 0, sizeof(cpumask_t));
+       } else if (len > sizeof(cpumask_t)) {
+               len = sizeof(cpumask_t);
+       }
+       return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
+}
+
+/**
+ * sys_sched_setaffinity - set the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to the new cpu mask
+ */
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+               unsigned long __user *, user_mask_ptr)
+{
+       cpumask_t new_mask;
+       int retval;
+
+       retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
+       if (retval)
+               return retval;
+
+       return sched_setaffinity(pid, &new_mask);
+}
+
+long sched_getaffinity(pid_t pid, cpumask_t *mask)
+{
+       struct task_struct *p;
+       int retval;
+
+       get_online_cpus();
+       read_lock(&tasklist_lock);
+
+       retval = -ESRCH;
+       p = find_process_by_pid(pid);
+       if (!p)
+               goto out_unlock;
+
+       retval = security_task_getscheduler(p);
+       if (retval)
+               goto out_unlock;
+
+       cpus_and(*mask, p->cpus_allowed, cpu_online_map);
+
+out_unlock:
+       read_unlock(&tasklist_lock);
+       put_online_cpus();
+
+       return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to hold the current cpu mask
+ */
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+               unsigned long __user *, user_mask_ptr)
+{
+       int ret;
+       cpumask_t mask;
+
+       if (len < sizeof(cpumask_t))
+               return -EINVAL;
+
+       ret = sched_getaffinity(pid, &mask);
+       if (ret < 0)
+               return ret;
+
+       if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
+               return -EFAULT;
+
+       return sizeof(cpumask_t);
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * This function yields the current CPU to other tasks. If there are no
+ * other threads running on this CPU then this function will return.
+ */
+SYSCALL_DEFINE0(sched_yield)
+{
+       struct rq *rq = this_rq_lock();
+
+       schedstat_inc(rq, yld_count);
+       current->sched_class->yield_task(rq);
+
+       /*
+        * Since we are going to call schedule() anyway, there's
+        * no need to preempt or enable interrupts:
+        */
+       __release(rq->lock);
+       spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
+       _raw_spin_unlock(&rq->lock);
+       preempt_enable_no_resched();
+
+       schedule();
+
+       return 0;
+}
+
+static void __cond_resched(void)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
+       __might_sleep(__FILE__, __LINE__);
+#endif
+       /*
+        * The BKS might be reacquired before we have dropped
+        * PREEMPT_ACTIVE, which could trigger a second
+        * cond_resched() call.
+        */
+       do {
+               add_preempt_count(PREEMPT_ACTIVE);
+               schedule();
+               sub_preempt_count(PREEMPT_ACTIVE);
+       } while (need_resched());
+}
+
+int __sched _cond_resched(void)
+{
+       if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
+                                       system_state == SYSTEM_RUNNING) {
+               __cond_resched();
+               return 1;
+       }
+       return 0;
+}
+EXPORT_SYMBOL(_cond_resched);
+
+/*
+ * cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * call schedule, and on return reacquire the lock.
+ *
+ * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
+ * operations here to prevent schedule() from being called twice (once via
+ * spin_unlock(), once by hand).
+ */
+int cond_resched_lock(spinlock_t *lock)
+{
+       int resched = need_resched() && system_state == SYSTEM_RUNNING;
+       int ret = 0;
+
+       if (spin_needbreak(lock) || resched) {
+               spin_unlock(lock);
+               if (resched && need_resched())
+                       __cond_resched();
+               else
+                       cpu_relax();
+               ret = 1;
+               spin_lock(lock);
+       }
+       return ret;
+}
+EXPORT_SYMBOL(cond_resched_lock);
+
+int __sched cond_resched_softirq(void)
+{
+       BUG_ON(!in_softirq());
+
+       if (need_resched() && system_state == SYSTEM_RUNNING) {
+               local_bh_enable();
+               __cond_resched();
+               local_bh_disable();
+               return 1;
+       }
+       return 0;
+}
+EXPORT_SYMBOL(cond_resched_softirq);
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * This is a shortcut for kernel-space yielding - it marks the
+ * thread runnable and calls sys_sched_yield().
+ */
+void __sched yield(void)
+{
+       set_current_state(TASK_RUNNING);
+       sys_sched_yield();
+}
+EXPORT_SYMBOL(yield);
+
+/*
+ * This task is about to go to sleep on IO. Increment rq->nr_iowait so
+ * that process accounting knows that this is a task in IO wait state.
+ *
+ * But don't do that if it is a deliberate, throttling IO wait (this task
+ * has set its backing_dev_info: the queue against which it should throttle)
+ */
+void __sched io_schedule(void)
+{
+       struct rq *rq = &__raw_get_cpu_var(runqueues);
+
+       delayacct_blkio_start();
+       atomic_inc(&rq->nr_iowait);
+       schedule();
+       atomic_dec(&rq->nr_iowait);
+       delayacct_blkio_end();
+}
+EXPORT_SYMBOL(io_schedule);
+
+long __sched io_schedule_timeout(long timeout)
+{
+       struct rq *rq = &__raw_get_cpu_var(runqueues);
+       long ret;
+
+       delayacct_blkio_start();
+       atomic_inc(&rq->nr_iowait);
+       ret = schedule_timeout(timeout);
+       atomic_dec(&rq->nr_iowait);
+       delayacct_blkio_end();
+       return ret;
+}
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * this syscall returns the maximum rt_priority that can be used
+ * by a given scheduling class.
+ */
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
+{
+       int ret = -EINVAL;
+
+       switch (policy) {
+       case SCHED_FIFO:
+       case SCHED_RR:
+               ret = MAX_USER_RT_PRIO-1;
+               break;
+       case SCHED_NORMAL:
+       case SCHED_BATCH:
+       case SCHED_IDLE:
+               ret = 0;
+               break;
+       }
+       return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * this syscall returns the minimum rt_priority that can be used
+ * by a given scheduling class.
+ */
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
+{
+       int ret = -EINVAL;
+
+       switch (policy) {
+       case SCHED_FIFO:
+       case SCHED_RR:
+               ret = 1;
+               break;
+       case SCHED_NORMAL:
+       case SCHED_BATCH:
+       case SCHED_IDLE:
+               ret = 0;
+       }
+       return ret;
+}
+
+/**
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
+ * @pid: pid of the process.
+ * @interval: userspace pointer to the timeslice value.
+ *
+ * this syscall writes the default timeslice value of a given process
+ * into the user-space timespec buffer. A value of '0' means infinity.
+ */
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+               struct timespec __user *, interval)
+{
+       struct task_struct *p;
+       unsigned int time_slice;
+       int retval;
+       struct timespec t;
+
+       if (pid < 0)
+               return -EINVAL;
+
+       retval = -ESRCH;
+       read_lock(&tasklist_lock);
+       p = find_process_by_pid(pid);
+       if (!p)
+               goto out_unlock;
+
+       retval = security_task_getscheduler(p);
+       if (retval)
+               goto out_unlock;
+
+       /*
+        * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
+        * tasks that are on an otherwise idle runqueue:
+        */
+       time_slice = 0;
+       if (p->policy == SCHED_RR) {
+               time_slice = DEF_TIMESLICE;
+       } else if (p->policy != SCHED_FIFO) {
+               struct sched_entity *se = &p->se;
+               unsigned long flags;
+               struct rq *rq;
+
+               rq = task_rq_lock(p, &flags);
+               if (rq->cfs.load.weight)
+                       time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
+               task_rq_unlock(rq, &flags);
+       }
+       read_unlock(&tasklist_lock);
+       jiffies_to_timespec(time_slice, &t);
+       retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
+       return retval;
+
+out_unlock:
+       read_unlock(&tasklist_lock);
+       return retval;
+}
+
+static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
+
+void sched_show_task(struct task_struct *p)
+{
+       unsigned long free = 0;
+       unsigned state;
+
+       state = p->state ? __ffs(p->state) + 1 : 0;
+       printk(KERN_INFO "%-13.13s %c", p->comm,
+               state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
+#if BITS_PER_LONG == 32
+       if (state == TASK_RUNNING)
+               printk(KERN_CONT " running  ");
+       else
+               printk(KERN_CONT " %08lx ", thread_saved_pc(p));
+#else
+       if (state == TASK_RUNNING)
+               printk(KERN_CONT "  running task    ");
+       else
+               printk(KERN_CONT " %016lx ", thread_saved_pc(p));
+#endif
+#ifdef CONFIG_DEBUG_STACK_USAGE
+       {
+               unsigned long *n = end_of_stack(p);
+               while (!*n)
+                       n++;
+               free = (unsigned long)n - (unsigned long)end_of_stack(p);
+       }
+#endif
+       printk(KERN_CONT "%5lu %5d %6d\n", free,
+               task_pid_nr(p), task_pid_nr(p->real_parent));
+
+       show_stack(p, NULL);
+}
+
+void show_state_filter(unsigned long state_filter)
+{
+       struct task_struct *g, *p;
+
+#if BITS_PER_LONG == 32
+       printk(KERN_INFO
+               "  task                PC stack   pid father\n");
+#else
+       printk(KERN_INFO
+               "  task                        PC stack   pid father\n");
+#endif
+       read_lock(&tasklist_lock);
+       do_each_thread(g, p) {
+               /*
+                * reset the NMI-timeout, listing all files on a slow
+                * console might take alot of time:
+                */
+               touch_nmi_watchdog();
+               if (!state_filter || (p->state & state_filter))
+                       sched_show_task(p);
+       } while_each_thread(g, p);
+
+       touch_all_softlockup_watchdogs();
+
+#ifdef CONFIG_SCHED_DEBUG
+       sysrq_sched_debug_show();
+#endif
+       read_unlock(&tasklist_lock);
+       /*
+        * Only show locks if all tasks are dumped:
+        */
+       if (state_filter == -1)
+               debug_show_all_locks();
+}
+
+void __cpuinit init_idle_bootup_task(struct task_struct *idle)
+{
+       idle->sched_class = &idle_sched_class;
+}
+
+/**
+ * init_idle - set up an idle thread for a given CPU
+ * @idle: task in question
+ * @cpu: cpu the idle task belongs to
+ *
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
+ * flag, to make booting more robust.
+ */
+void __cpuinit init_idle(struct task_struct *idle, int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long flags;
+
+       __sched_fork(idle);
+       idle->se.exec_start = sched_clock();
+
+       idle->prio = idle->normal_prio = MAX_PRIO;
+       idle->cpus_allowed = cpumask_of_cpu(cpu);
+       __set_task_cpu(idle, cpu);
+
+       spin_lock_irqsave(&rq->lock, flags);
+       rq->curr = rq->idle = idle;
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
+       idle->oncpu = 1;
+#endif
+       spin_unlock_irqrestore(&rq->lock, flags);
+
+       /* Set the preempt count _outside_ the spinlocks! */
+#if defined(CONFIG_PREEMPT)
+       task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
+#else
+       task_thread_info(idle)->preempt_count = 0;
+#endif
+       /*
+        * The idle tasks have their own, simple scheduling class:
+        */
+       idle->sched_class = &idle_sched_class;
+}
+
+/*
+ * In a system that switches off the HZ timer nohz_cpu_mask
+ * indicates which cpus entered this state. This is used
+ * in the rcu update to wait only for active cpus. For system
+ * which do not switch off the HZ timer nohz_cpu_mask should
+ * always be CPU_MASK_NONE.
+ */
+cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
+
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static inline void sched_init_granularity(void)
+{
+       unsigned int factor = 1 + ilog2(num_online_cpus());
+       const unsigned long limit = 200000000;
+
+       sysctl_sched_min_granularity *= factor;
+       if (sysctl_sched_min_granularity > limit)
+               sysctl_sched_min_granularity = limit;
+
+       sysctl_sched_latency *= factor;
+       if (sysctl_sched_latency > limit)
+               sysctl_sched_latency = limit;
+
+       sysctl_sched_wakeup_granularity *= factor;
+
+       sysctl_sched_shares_ratelimit *= factor;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * This is how migration works:
+ *
+ * 1) we queue a struct migration_req structure in the source CPU's
+ *    runqueue and wake up that CPU's migration thread.
+ * 2) we down() the locked semaphore => thread blocks.
+ * 3) migration thread wakes up (implicitly it forces the migrated
+ *    thread off the CPU)
+ * 4) it gets the migration request and checks whether the migrated
+ *    task is still in the wrong runqueue.
+ * 5) if it's in the wrong runqueue then the migration thread removes
+ *    it and puts it into the right queue.
+ * 6) migration thread up()s the semaphore.
+ * 7) we wake up and the migration is done.
+ */
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)
+{
+       struct migration_req req;
+       unsigned long flags;
+       struct rq *rq;
+       int ret = 0;
+
+       rq = task_rq_lock(p, &flags);
+       if (!cpus_intersects(*new_mask, cpu_online_map)) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
+                    !cpus_equal(p->cpus_allowed, *new_mask))) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       if (p->sched_class->set_cpus_allowed)
+               p->sched_class->set_cpus_allowed(p, new_mask);
+       else {
+               p->cpus_allowed = *new_mask;
+               p->rt.nr_cpus_allowed = cpus_weight(*new_mask);
+       }
+
+       /* Can the task run on the task's current CPU? If so, we're done */
+       if (cpu_isset(task_cpu(p), *new_mask))
+               goto out;
+
+       if (migrate_task(p, any_online_cpu(*new_mask), &req)) {
+               /* Need help from migration thread: drop lock and wait. */
+               task_rq_unlock(rq, &flags);
+               wake_up_process(rq->migration_thread);
+               wait_for_completion(&req.done);
+               tlb_migrate_finish(p->mm);
+               return 0;
+       }
+out:
+       task_rq_unlock(rq, &flags);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+
+/*
+ * Move (not current) task off this cpu, onto dest cpu. We're doing
+ * this because either it can't run here any more (set_cpus_allowed()
+ * away from this CPU, or CPU going down), or because we're
+ * attempting to rebalance this task on exec (sched_exec).
+ *
+ * So we race with normal scheduler movements, but that's OK, as long
+ * as the task is no longer on this CPU.
+ *
+ * Returns non-zero if task was successfully migrated.
+ */
+static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
+{
+       struct rq *rq_dest, *rq_src;
+       int ret = 0, on_rq;
+
+       if (unlikely(!cpu_active(dest_cpu)))
+               return ret;
+
+       rq_src = cpu_rq(src_cpu);
+       rq_dest = cpu_rq(dest_cpu);
+
+       double_rq_lock(rq_src, rq_dest);
+       /* Already moved. */
+       if (task_cpu(p) != src_cpu)
+               goto done;
+       /* Affinity changed (again). */
+       if (!cpu_isset(dest_cpu, p->cpus_allowed))
+               goto fail;
+
+       on_rq = p->se.on_rq;
+       if (on_rq)
+               deactivate_task(rq_src, p, 0);
+
+       set_task_cpu(p, dest_cpu);
+       if (on_rq) {
+               activate_task(rq_dest, p, 0);
+               check_preempt_curr(rq_dest, p);
+       }
+done:
+       ret = 1;
+fail:
+       double_rq_unlock(rq_src, rq_dest);
+       return ret;
+}
+
+/*
+ * migration_thread - this is a highprio system thread that performs
+ * thread migration by bumping thread off CPU then 'pushing' onto
+ * another runqueue.
+ */
+static int migration_thread(void *data)
+{
+       int cpu = (long)data;
+       struct rq *rq;
+
+       rq = cpu_rq(cpu);
+       BUG_ON(rq->migration_thread != current);
+
+       set_current_state(TASK_INTERRUPTIBLE);
+       while (!kthread_should_stop()) {
+               struct migration_req *req;
+               struct list_head *head;
+
+               spin_lock_irq(&rq->lock);
+
+               if (cpu_is_offline(cpu)) {
+                       spin_unlock_irq(&rq->lock);
+                       goto wait_to_die;
+               }
+
+               if (rq->active_balance) {
+                       active_load_balance(rq, cpu);
+                       rq->active_balance = 0;
+               }
+
+               head = &rq->migration_queue;
+
+               if (list_empty(head)) {
+                       spin_unlock_irq(&rq->lock);
+                       schedule();
+                       set_current_state(TASK_INTERRUPTIBLE);
+                       continue;
+               }
+               req = list_entry(head->next, struct migration_req, list);
+               list_del_init(head->next);
+
+               spin_unlock(&rq->lock);
+               __migrate_task(req->task, cpu, req->dest_cpu);
+               local_irq_enable();
+
+               complete(&req->done);
+       }
+       __set_current_state(TASK_RUNNING);
+       return 0;
+
+wait_to_die:
+       /* Wait for kthread_stop */
+       set_current_state(TASK_INTERRUPTIBLE);
+       while (!kthread_should_stop()) {
+               schedule();
+               set_current_state(TASK_INTERRUPTIBLE);
+       }
+       __set_current_state(TASK_RUNNING);
+       return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
+{
+       int ret;
+
+       local_irq_disable();
+       ret = __migrate_task(p, src_cpu, dest_cpu);
+       local_irq_enable();
+       return ret;
+}
+
+/*
+ * Figure out where task on dead CPU should go, use force if necessary.
+ * NOTE: interrupts should be disabled by the caller
+ */
+static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
+{
+       unsigned long flags;
+       cpumask_t mask;
+       struct rq *rq;
+       int dest_cpu;
+
+       do {
+               /* On same node? */
+               mask = node_to_cpumask(cpu_to_node(dead_cpu));
+               cpus_and(mask, mask, p->cpus_allowed);
+               dest_cpu = any_online_cpu(mask);
+
+               /* On any allowed CPU? */
+               if (dest_cpu >= nr_cpu_ids)
+                       dest_cpu = any_online_cpu(p->cpus_allowed);
+
+               /* No more Mr. Nice Guy. */
+               if (dest_cpu >= nr_cpu_ids) {
+                       cpumask_t cpus_allowed;
+
+                       cpuset_cpus_allowed_locked(p, &cpus_allowed);
+                       /*
+                        * Try to stay on the same cpuset, where the
+                        * current cpuset may be a subset of all cpus.
+                        * The cpuset_cpus_allowed_locked() variant of
+                        * cpuset_cpus_allowed() will not block. It must be
+                        * called within calls to cpuset_lock/cpuset_unlock.
+                        */
+                       rq = task_rq_lock(p, &flags);
+                       p->cpus_allowed = cpus_allowed;
+                       dest_cpu = any_online_cpu(p->cpus_allowed);
+                       task_rq_unlock(rq, &flags);
+
+                       /*
+                        * Don't tell them about moving exiting tasks or
+                        * kernel threads (both mm NULL), since they never
+                        * leave kernel.
+                        */
+                       if (p->mm && printk_ratelimit()) {
+                               printk(KERN_INFO "process %d (%s) no "
+                                      "longer affine to cpu%d\n",
+                                       task_pid_nr(p), p->comm, dead_cpu);
+                       }
+               }
+       } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
+}
+
+/*
+ * While a dead CPU has no uninterruptible tasks queued at this point,
+ * it might still have a nonzero ->nr_uninterruptible counter, because
+ * for performance reasons the counter is not stricly tracking tasks to
+ * their home CPUs. So we just add the counter to another CPU's counter,
+ * to keep the global sum constant after CPU-down:
+ */
+static void migrate_nr_uninterruptible(struct rq *rq_src)
+{
+       struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
+       unsigned long flags;
+
+       local_irq_save(flags);
+       double_rq_lock(rq_src, rq_dest);
+       rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
+       rq_src->nr_uninterruptible = 0;
+       double_rq_unlock(rq_src, rq_dest);
+       local_irq_restore(flags);
+}
+
+/* Run through task list and migrate tasks from the dead cpu. */
+static void migrate_live_tasks(int src_cpu)
+{
+       struct task_struct *p, *t;
+
+       read_lock(&tasklist_lock);
+
+       do_each_thread(t, p) {
+               if (p == current)
+                       continue;
+
+               if (task_cpu(p) == src_cpu)
+                       move_task_off_dead_cpu(src_cpu, p);
+       } while_each_thread(t, p);
+
+       read_unlock(&tasklist_lock);
+}
+
+/*
+ * Schedules idle task to be the next runnable task on current CPU.
+ * It does so by boosting its priority to highest possible.
+ * Used by CPU offline code.
+ */
+void sched_idle_next(void)
+{
+       int this_cpu = smp_processor_id();
+       struct rq *rq = cpu_rq(this_cpu);
+       struct task_struct *p = rq->idle;
+       unsigned long flags;
+
+       /* cpu has to be offline */
+       BUG_ON(cpu_online(this_cpu));
+
+       /*
+        * Strictly not necessary since rest of the CPUs are stopped by now
+        * and interrupts disabled on the current cpu.
+        */
+       spin_lock_irqsave(&rq->lock, flags);
+
+       __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
+
+       update_rq_clock(rq);
+       activate_task(rq, p, 0);
+
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+/*
+ * Ensures that the idle task is using init_mm right before its cpu goes
+ * offline.
+ */
+void idle_task_exit(void)
+{
+       struct mm_struct *mm = current->active_mm;
+
+       BUG_ON(cpu_online(smp_processor_id()));
+
+       if (mm != &init_mm)
+               switch_mm(mm, &init_mm, current);
+       mmdrop(mm);
+}
+
+/* called under rq->lock with disabled interrupts */
+static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
+{
+       struct rq *rq = cpu_rq(dead_cpu);
+
+       /* Must be exiting, otherwise would be on tasklist. */
+       BUG_ON(!p->exit_state);
+
+       /* Cannot have done final schedule yet: would have vanished. */
+       BUG_ON(p->state == TASK_DEAD);
+
+       get_task_struct(p);
+
+       /*
+        * Drop lock around migration; if someone else moves it,
+        * that's OK. No task can be added to this CPU, so iteration is
+        * fine.
+        */
+       spin_unlock_irq(&rq->lock);
+       move_task_off_dead_cpu(dead_cpu, p);
+       spin_lock_irq(&rq->lock);
+
+       put_task_struct(p);
+}
+
+/* release_task() removes task from tasklist, so we won't find dead tasks. */
+static void migrate_dead_tasks(unsigned int dead_cpu)
+{
+       struct rq *rq = cpu_rq(dead_cpu);
+       struct task_struct *next;
+
+       for ( ; ; ) {
+               if (!rq->nr_running)
+                       break;
+               update_rq_clock(rq);
+               next = pick_next_task(rq, rq->curr);
+               if (!next)
+                       break;
+               next->sched_class->put_prev_task(rq, next);
+               migrate_dead(dead_cpu, next);
+
+       }
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
+
+static struct ctl_table sd_ctl_dir[] = {
+       {
+               .procname       = "sched_domain",
+               .mode           = 0555,
+       },
+       {0, },
+};
+
+static struct ctl_table sd_ctl_root[] = {
+       {
+               .ctl_name       = CTL_KERN,
+               .procname       = "kernel",
+               .mode           = 0555,
+               .child          = sd_ctl_dir,
+       },
+       {0, },
+};
+
+static struct ctl_table *sd_alloc_ctl_entry(int n)
+{
+       struct ctl_table *entry =
+               kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
+
+       return entry;
+}
+
+static void sd_free_ctl_entry(struct ctl_table **tablep)
+{
+       struct ctl_table *entry;
+
+       /*
+        * In the intermediate directories, both the child directory and
+        * procname are dynamically allocated and could fail but the mode
+        * will always be set. In the lowest directory the names are
+        * static strings and all have proc handlers.
+        */
+       for (entry = *tablep; entry->mode; entry++) {
+               if (entry->child)
+                       sd_free_ctl_entry(&entry->child);
+               if (entry->proc_handler == NULL)
+                       kfree(entry->procname);
+       }
+
+       kfree(*tablep);
+       *tablep = NULL;
+}
+
+static void
+set_table_entry(struct ctl_table *entry,
+               const char *procname, void *data, int maxlen,
+               mode_t mode, proc_handler *proc_handler)
+{
+       entry->procname = procname;
+       entry->data = data;
+       entry->maxlen = maxlen;
+       entry->mode = mode;
+       entry->proc_handler = proc_handler;
+}
+
+static struct ctl_table *
+sd_alloc_ctl_domain_table(struct sched_domain *sd)
+{
+       struct ctl_table *table = sd_alloc_ctl_entry(12);
+
+       if (table == NULL)
+               return NULL;
+
+       set_table_entry(&table[0], "min_interval", &sd->min_interval,
+               sizeof(long), 0644, proc_doulongvec_minmax);
+       set_table_entry(&table[1], "max_interval", &sd->max_interval,
+               sizeof(long), 0644, proc_doulongvec_minmax);
+       set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[9], "cache_nice_tries",
+               &sd->cache_nice_tries,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       set_table_entry(&table[10], "flags", &sd->flags,
+               sizeof(int), 0644, proc_dointvec_minmax);
+       /* &table[11] is terminator */
+
+       return table;
+}
+
+static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
+{
+       struct ctl_table *entry, *table;
+       struct sched_domain *sd;
+       int domain_num = 0, i;
+       char buf[32];
+
+       for_each_domain(cpu, sd)
+               domain_num++;
+       entry = table = sd_alloc_ctl_entry(domain_num + 1);
+       if (table == NULL)
+               return NULL;
+
+       i = 0;
+       for_each_domain(cpu, sd) {
+               snprintf(buf, 32, "domain%d", i);
+               entry->procname = kstrdup(buf, GFP_KERNEL);
+               entry->mode = 0555;
+               entry->child = sd_alloc_ctl_domain_table(sd);
+               entry++;
+               i++;
+       }
+       return table;
+}
+
+static struct ctl_table_header *sd_sysctl_header;
+static void register_sched_domain_sysctl(void)
+{
+       int i, cpu_num = num_online_cpus();
+       struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
+       char buf[32];
+
+       WARN_ON(sd_ctl_dir[0].child);
+       sd_ctl_dir[0].child = entry;
+
+       if (entry == NULL)
+               return;
+
+       for_each_online_cpu(i) {
+               snprintf(buf, 32, "cpu%d", i);
+               entry->procname = kstrdup(buf, GFP_KERNEL);
+               entry->mode = 0555;
+               entry->child = sd_alloc_ctl_cpu_table(i);
+               entry++;
+       }
+
+       WARN_ON(sd_sysctl_header);
+       sd_sysctl_header = register_sysctl_table(sd_ctl_root);
+}
+
+/* may be called multiple times per register */
+static void unregister_sched_domain_sysctl(void)
+{
+       if (sd_sysctl_header)
+               unregister_sysctl_table(sd_sysctl_header);
+       sd_sysctl_header = NULL;
+       if (sd_ctl_dir[0].child)
+               sd_free_ctl_entry(&sd_ctl_dir[0].child);
+}
+#else
+static void register_sched_domain_sysctl(void)
+{
+}
+static void unregister_sched_domain_sysctl(void)
+{
+}
+#endif
+
+static void set_rq_online(struct rq *rq)
+{
+       if (!rq->online) {
+               const struct sched_class *class;
+
+               cpu_set(rq->cpu, rq->rd->online);
+               rq->online = 1;
+
+               for_each_class(class) {
+                       if (class->rq_online)
+                               class->rq_online(rq);
+               }
+       }
+}
+
+static void set_rq_offline(struct rq *rq)
+{
+       if (rq->online) {
+               const struct sched_class *class;
+
+               for_each_class(class) {
+                       if (class->rq_offline)
+                               class->rq_offline(rq);
+               }
+
+               cpu_clear(rq->cpu, rq->rd->online);
+               rq->online = 0;
+       }
+}
+
+/*
+ * migration_call - callback that gets triggered when a CPU is added.
+ * Here we can start up the necessary migration thread for the new CPU.
+ */
+static int __cpuinit
+migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+       struct task_struct *p;
+       int cpu = (long)hcpu;
+       unsigned long flags;
+       struct rq *rq;
+
+       switch (action) {
+
+       case CPU_UP_PREPARE:
+       case CPU_UP_PREPARE_FROZEN:
+               p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
+               if (IS_ERR(p))
+                       return NOTIFY_BAD;
+               kthread_bind(p, cpu);
+               /* Must be high prio: stop_machine expects to yield to it. */
+               rq = task_rq_lock(p, &flags);
+               __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
+               task_rq_unlock(rq, &flags);
+               cpu_rq(cpu)->migration_thread = p;
+               break;
+
+       case CPU_ONLINE:
+       case CPU_ONLINE_FROZEN:
+               /* Strictly unnecessary, as first user will wake it. */
+               wake_up_process(cpu_rq(cpu)->migration_thread);
+
+               /* Update our root-domain */
+               rq = cpu_rq(cpu);
+               spin_lock_irqsave(&rq->lock, flags);
+               if (rq->rd) {
+                       BUG_ON(!cpu_isset(cpu, rq->rd->span));
+
+                       set_rq_online(rq);
+               }
+               spin_unlock_irqrestore(&rq->lock, flags);
+               break;
+
+#ifdef CONFIG_HOTPLUG_CPU
+       case CPU_UP_CANCELED:
+       case CPU_UP_CANCELED_FROZEN:
+               if (!cpu_rq(cpu)->migration_thread)
+                       break;
+               /* Unbind it from offline cpu so it can run. Fall thru. */
+               kthread_bind(cpu_rq(cpu)->migration_thread,
+                            any_online_cpu(cpu_online_map));
+               kthread_stop(cpu_rq(cpu)->migration_thread);
+               cpu_rq(cpu)->migration_thread = NULL;
+               break;
+
+       case CPU_DEAD:
+       case CPU_DEAD_FROZEN:
+               cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
+               migrate_live_tasks(cpu);
+               rq = cpu_rq(cpu);
+               kthread_stop(rq->migration_thread);
+               rq->migration_thread = NULL;
+               /* Idle task back to normal (off runqueue, low prio) */
+               spin_lock_irq(&rq->lock);
+               update_rq_clock(rq);
+               deactivate_task(rq, rq->idle, 0);
+               rq->idle->static_prio = MAX_PRIO;
+               __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
+               rq->idle->sched_class = &idle_sched_class;
+               migrate_dead_tasks(cpu);
+               spin_unlock_irq(&rq->lock);
+               cpuset_unlock();
+               migrate_nr_uninterruptible(rq);
+               BUG_ON(rq->nr_running != 0);
+
+               /*
+                * No need to migrate the tasks: it was best-effort if
+                * they didn't take sched_hotcpu_mutex. Just wake up
+                * the requestors.
+                */
+               spin_lock_irq(&rq->lock);
+               while (!list_empty(&rq->migration_queue)) {
+                       struct migration_req *req;
+
+                       req = list_entry(rq->migration_queue.next,
+                                        struct migration_req, list);
+                       list_del_init(&req->list);
+                       spin_unlock_irq(&rq->lock);
+                       complete(&req->done);
+                       spin_lock_irq(&rq->lock);
+               }
+               spin_unlock_irq(&rq->lock);
+               break;
+
+       case CPU_DYING:
+       case CPU_DYING_FROZEN:
+               /* Update our root-domain */
+               rq = cpu_rq(cpu);
+               spin_lock_irqsave(&rq->lock, flags);
+               if (rq->rd) {
+                       BUG_ON(!cpu_isset(cpu, rq->rd->span));
+                       set_rq_offline(rq);
+               }
+               spin_unlock_irqrestore(&rq->lock, flags);
+               break;
+#endif
+       }
+       return NOTIFY_OK;
+}
+
+/* Register at highest priority so that task migration (migrate_all_tasks)
+ * happens before everything else.
+ */
+static struct notifier_block __cpuinitdata migration_notifier = {
+       .notifier_call = migration_call,
+       .priority = 10
+};
+
+static int __init migration_init(void)
+{
+       void *cpu = (void *)(long)smp_processor_id();
+       int err;
+
+       /* Start one for the boot CPU: */
+       err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+       BUG_ON(err == NOTIFY_BAD);
+       migration_call(&migration_notifier, CPU_ONLINE, cpu);
+       register_cpu_notifier(&migration_notifier);
+
+       return err;
+}
+early_initcall(migration_init);
+#endif
+
+#ifdef CONFIG_SMP
+
+#ifdef CONFIG_SCHED_DEBUG
+
+static inline const char *sd_level_to_string(enum sched_domain_level lvl)
+{
+       switch (lvl) {
+       case SD_LV_NONE:
+                       return "NONE";
+       case SD_LV_SIBLING:
+                       return "SIBLING";
+       case SD_LV_MC:
+                       return "MC";
+       case SD_LV_CPU:
+                       return "CPU";
+       case SD_LV_NODE:
+                       return "NODE";
+       case SD_LV_ALLNODES:
+                       return "ALLNODES";
+       case SD_LV_MAX:
+                       return "MAX";
+
+       }
+       return "MAX";
+}
+
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
+                                 cpumask_t *groupmask)
+{
+       struct sched_group *group = sd->groups;
+       char str[256];
+
+       cpulist_scnprintf(str, sizeof(str), sd->span);
+       cpus_clear(*groupmask);
+
+       printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
+
+       if (!(sd->flags & SD_LOAD_BALANCE)) {
+               printk("does not load-balance\n");
+               if (sd->parent)
+                       printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
+                                       " has parent");
+               return -1;
+       }
+
+       printk(KERN_CONT "span %s level %s\n",
+               str, sd_level_to_string(sd->level));
+
+       if (!cpu_isset(cpu, sd->span)) {
+               printk(KERN_ERR "ERROR: domain->span does not contain "
+                               "CPU%d\n", cpu);
+       }
+       if (!cpu_isset(cpu, group->cpumask)) {
+               printk(KERN_ERR "ERROR: domain->groups does not contain"
+                               " CPU%d\n", cpu);
+       }
+
+       printk(KERN_DEBUG "%*s groups:", level + 1, "");
+       do {
+               if (!group) {
+                       printk("\n");
+                       printk(KERN_ERR "ERROR: group is NULL\n");
+                       break;
+               }
+
+               if (!group->__cpu_power) {
+                       printk(KERN_CONT "\n");
+                       printk(KERN_ERR "ERROR: domain->cpu_power not "
+                                       "set\n");
+                       break;
+               }
+
+               if (!cpus_weight(group->cpumask)) {
+                       printk(KERN_CONT "\n");
+                       printk(KERN_ERR "ERROR: empty group\n");
+                       break;
+               }
+
+               if (cpus_intersects(*groupmask, group->cpumask)) {
+                       printk(KERN_CONT "\n");
+                       printk(KERN_ERR "ERROR: repeated CPUs\n");
+                       break;
+               }
+
+               cpus_or(*groupmask, *groupmask, group->cpumask);
+
+               cpulist_scnprintf(str, sizeof(str), group->cpumask);
+               printk(KERN_CONT " %s", str);
+
+               group = group->next;
+       } while (group != sd->groups);
+       printk(KERN_CONT "\n");
+
+       if (!cpus_equal(sd->span, *groupmask))
+               printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+       if (sd->parent && !cpus_subset(*groupmask, sd->parent->span))
+               printk(KERN_ERR "ERROR: parent span is not a superset "
+                       "of domain->span\n");
+       return 0;
+}
+
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+       cpumask_t *groupmask;
+       int level = 0;
+
+       if (!sd) {
+               printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
+               return;
+       }
+
+       printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
+
+       groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
+       if (!groupmask) {
+               printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
+               return;
+       }
+
+       for (;;) {
+               if (sched_domain_debug_one(sd, cpu, level, groupmask))
+                       break;
+               level++;
+               sd = sd->parent;
+               if (!sd)
+                       break;
+       }
+       kfree(groupmask);
+}
+#else /* !CONFIG_SCHED_DEBUG */
+# define sched_domain_debug(sd, cpu) do { } while (0)
+#endif /* CONFIG_SCHED_DEBUG */
+
+static int sd_degenerate(struct sched_domain *sd)
+{
+       if (cpus_weight(sd->span) == 1)
+               return 1;
+
+       /* Following flags need at least 2 groups */
+       if (sd->flags & (SD_LOAD_BALANCE |
+                        SD_BALANCE_NEWIDLE |
+                        SD_BALANCE_FORK |
+                        SD_BALANCE_EXEC |
+                        SD_SHARE_CPUPOWER |
+                        SD_SHARE_PKG_RESOURCES)) {
+               if (sd->groups != sd->groups->next)
+                       return 0;
+       }
+
+       /* Following flags don't use groups */
+       if (sd->flags & (SD_WAKE_IDLE |
+                        SD_WAKE_AFFINE |
+                        SD_WAKE_BALANCE))
+               return 0;
+
+       return 1;
+}
+
+static int
+sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
+{
+       unsigned long cflags = sd->flags, pflags = parent->flags;
+
+       if (sd_degenerate(parent))
+               return 1;
+
+       if (!cpus_equal(sd->span, parent->span))
+               return 0;
+
+       /* Does parent contain flags not in child? */
+       /* WAKE_BALANCE is a subset of WAKE_AFFINE */
+       if (cflags & SD_WAKE_AFFINE)
+               pflags &= ~SD_WAKE_BALANCE;
+       /* Flags needing groups don't count if only 1 group in parent */
+       if (parent->groups == parent->groups->next) {
+               pflags &= ~(SD_LOAD_BALANCE |
+                               SD_BALANCE_NEWIDLE |
+                               SD_BALANCE_FORK |
+                               SD_BALANCE_EXEC |
+                               SD_SHARE_CPUPOWER |
+                               SD_SHARE_PKG_RESOURCES);
+       }
+       if (~cflags & pflags)
+               return 0;
+
+       return 1;
+}
+
+static void rq_attach_root(struct rq *rq, struct root_domain *rd)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&rq->lock, flags);
+
+       if (rq->rd) {
+               struct root_domain *old_rd = rq->rd;
+
+               if (cpu_isset(rq->cpu, old_rd->online))
+                       set_rq_offline(rq);
+
+               cpu_clear(rq->cpu, old_rd->span);
+
+               if (atomic_dec_and_test(&old_rd->refcount))
+                       kfree(old_rd);
+       }
+
+       atomic_inc(&rd->refcount);
+       rq->rd = rd;
+
+       cpu_set(rq->cpu, rd->span);
+       if (cpu_isset(rq->cpu, cpu_online_map))
+               set_rq_online(rq);
+
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static void init_rootdomain(struct root_domain *rd)
+{
+       memset(rd, 0, sizeof(*rd));
+
+       cpus_clear(rd->span);
+       cpus_clear(rd->online);
+
+       cpupri_init(&rd->cpupri);
+}
+
+static void init_defrootdomain(void)
+{
+       init_rootdomain(&def_root_domain);
+       atomic_set(&def_root_domain.refcount, 1);
+}
+
+static struct root_domain *alloc_rootdomain(void)
+{
+       struct root_domain *rd;
+
+       rd = kmalloc(sizeof(*rd), GFP_KERNEL);
+       if (!rd)
+               return NULL;
+
+       init_rootdomain(rd);
+
+       return rd;
+}
+
+/*
+ * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
+ * hold the hotplug lock.
+ */
+static void
+cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+       struct sched_domain *tmp;
+
+       /* Remove the sched domains which do not contribute to scheduling. */
+       for (tmp = sd; tmp; ) {
+               struct sched_domain *parent = tmp->parent;
+               if (!parent)
+                       break;
+
+               if (sd_parent_degenerate(tmp, parent)) {
+                       tmp->parent = parent->parent;
+                       if (parent->parent)
+                               parent->parent->child = tmp;
+               } else
+                       tmp = tmp->parent;
+       }
+
+       if (sd && sd_degenerate(sd)) {
+               sd = sd->parent;
+               if (sd)
+                       sd->child = NULL;
+       }
+
+       sched_domain_debug(sd, cpu);
+
+       rq_attach_root(rq, rd);
+       rcu_assign_pointer(rq->sd, sd);
+}
+
+/* cpus with isolated domains */
+static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
+
+/* Setup the mask of cpus configured for isolated domains */
+static int __init isolated_cpu_setup(char *str)
+{
+       static int __initdata ints[NR_CPUS];
+       int i;
+
+       str = get_options(str, ARRAY_SIZE(ints), ints);
+       cpus_clear(cpu_isolated_map);
+       for (i = 1; i <= ints[0]; i++)
+               if (ints[i] < NR_CPUS)
+                       cpu_set(ints[i], cpu_isolated_map);
+       return 1;
+}
+
+__setup("isolcpus=", isolated_cpu_setup);
+
+/*
+ * init_sched_build_groups takes the cpumask we wish to span, and a pointer
+ * to a function which identifies what group(along with sched group) a CPU
+ * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
+ * (due to the fact that we keep track of groups covered with a cpumask_t).
+ *
+ * init_sched_build_groups will build a circular linked list of the groups
+ * covered by the given span, and will set each group's ->cpumask correctly,
+ * and ->cpu_power to 0.
+ */
+static void
+init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map,
+                       int (*group_fn)(int cpu, const cpumask_t *cpu_map,
+                                       struct sched_group **sg,
+                                       cpumask_t *tmpmask),
+                       cpumask_t *covered, cpumask_t *tmpmask)
+{
+       struct sched_group *first = NULL, *last = NULL;
+       int i;
+
+       cpus_clear(*covered);
+
+       for_each_cpu_mask_nr(i, *span) {
+               struct sched_group *sg;
+               int group = group_fn(i, cpu_map, &sg, tmpmask);
+               int j;
+
+               if (cpu_isset(i, *covered))
+                       continue;
+
+               cpus_clear(sg->cpumask);
+               sg->__cpu_power = 0;
+
+               for_each_cpu_mask_nr(j, *span) {
+                       if (group_fn(j, cpu_map, NULL, tmpmask) != group)
+                               continue;
+
+                       cpu_set(j, *covered);
+                       cpu_set(j, sg->cpumask);
+               }
+               if (!first)
+                       first = sg;
+               if (last)
+                       last->next = sg;
+               last = sg;
+       }
+       last->next = first;
+}
+
+#define SD_NODES_PER_DOMAIN 16
+
+#ifdef CONFIG_NUMA
+
+/**
+ * find_next_best_node - find the next node to include in a sched_domain
+ * @node: node whose sched_domain we're building
+ * @used_nodes: nodes already in the sched_domain
+ *
+ * Find the next node to include in a given scheduling domain. Simply
+ * finds the closest node not already in the @used_nodes map.
+ *
+ * Should use nodemask_t.
+ */
+static int find_next_best_node(int node, nodemask_t *used_nodes)
+{
+       int i, n, val, min_val, best_node = 0;
+
+       min_val = INT_MAX;
+
+       for (i = 0; i < nr_node_ids; i++) {
+               /* Start at @node */
+               n = (node + i) % nr_node_ids;
+
+               if (!nr_cpus_node(n))
+                       continue;
+
+               /* Skip already used nodes */
+               if (node_isset(n, *used_nodes))
+                       continue;
+
+               /* Simple min distance search */
+               val = node_distance(node, n);
+
+               if (val < min_val) {
+                       min_val = val;
+                       best_node = n;
+               }
+       }
+
+       node_set(best_node, *used_nodes);
+       return best_node;
+}
+
+/**
+ * sched_domain_node_span - get a cpumask for a node's sched_domain
+ * @node: node whose cpumask we're constructing
+ * @span: resulting cpumask
+ *
+ * Given a node, construct a good cpumask for its sched_domain to span. It
+ * should be one that prevents unnecessary balancing, but also spreads tasks
+ * out optimally.
+ */
+static void sched_domain_node_span(int node, cpumask_t *span)
+{
+       nodemask_t used_nodes;
+       node_to_cpumask_ptr(nodemask, node);
+       int i;
+
+       cpus_clear(*span);
+       nodes_clear(used_nodes);
+
+       cpus_or(*span, *span, *nodemask);
+       node_set(node, used_nodes);
+
+       for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
+               int next_node = find_next_best_node(node, &used_nodes);
+
+               node_to_cpumask_ptr_next(nodemask, next_node);
+               cpus_or(*span, *span, *nodemask);
+       }
+}
+#endif /* CONFIG_NUMA */
+
+int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
+
+/*
+ * SMT sched-domains:
+ */
+#ifdef CONFIG_SCHED_SMT
+static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
+static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
+
+static int
+cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
+                cpumask_t *unused)
+{
+       if (sg)
+               *sg = &per_cpu(sched_group_cpus, cpu);
+       return cpu;
+}
+#endif /* CONFIG_SCHED_SMT */
+
+/*
+ * multi-core sched-domains:
+ */
+#ifdef CONFIG_SCHED_MC
+static DEFINE_PER_CPU(struct sched_domain, core_domains);
+static DEFINE_PER_CPU(struct sched_group, sched_group_core);
+#endif /* CONFIG_SCHED_MC */
+
+#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
+static int
+cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
+                 cpumask_t *mask)
+{
+       int group;
+
+       *mask = per_cpu(cpu_sibling_map, cpu);
+       cpus_and(*mask, *mask, *cpu_map);
+       group = first_cpu(*mask);
+       if (sg)
+               *sg = &per_cpu(sched_group_core, group);
+       return group;
+}
+#elif defined(CONFIG_SCHED_MC)
+static int
+cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
+                 cpumask_t *unused)
+{
+       if (sg)
+               *sg = &per_cpu(sched_group_core, cpu);
+       return cpu;
+}
+#endif
+
+static DEFINE_PER_CPU(struct sched_domain, phys_domains);
+static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
+
+static int
+cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
+                 cpumask_t *mask)
+{
+       int group;
+#ifdef CONFIG_SCHED_MC
+       *mask = cpu_coregroup_map(cpu);
+       cpus_and(*mask, *mask, *cpu_map);
+       group = first_cpu(*mask);
+#elif defined(CONFIG_SCHED_SMT)
+       *mask = per_cpu(cpu_sibling_map, cpu);
+       cpus_and(*mask, *mask, *cpu_map);
+       group = first_cpu(*mask);
+#else
+       group = cpu;
+#endif
+       if (sg)
+               *sg = &per_cpu(sched_group_phys, group);
+       return group;
+}
+
+#ifdef CONFIG_NUMA
+/*
+ * The init_sched_build_groups can't handle what we want to do with node
+ * groups, so roll our own. Now each node has its own list of groups which
+ * gets dynamically allocated.
+ */
+static DEFINE_PER_CPU(struct sched_domain, node_domains);
+static struct sched_group ***sched_group_nodes_bycpu;
+
+static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
+static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
+
+static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
+                                struct sched_group **sg, cpumask_t *nodemask)
+{
+       int group;
+
+       *nodemask = node_to_cpumask(cpu_to_node(cpu));
+       cpus_and(*nodemask, *nodemask, *cpu_map);
+       group = first_cpu(*nodemask);
+
+       if (sg)
+               *sg = &per_cpu(sched_group_allnodes, group);
+       return group;
+}
+
+static void init_numa_sched_groups_power(struct sched_group *group_head)
+{
+       struct sched_group *sg = group_head;
+       int j;
+
+       if (!sg)
+               return;
+       do {
+               for_each_cpu_mask_nr(j, sg->cpumask) {
+                       struct sched_domain *sd;
+
+                       sd = &per_cpu(phys_domains, j);
+                       if (j != first_cpu(sd->groups->cpumask)) {
+                               /*
+                                * Only add "power" once for each
+                                * physical package.
+                                */
+                               continue;
+                       }
+
+                       sg_inc_cpu_power(sg, sd->groups->__cpu_power);
+               }
+               sg = sg->next;
+       } while (sg != group_head);
+}
+#endif /* CONFIG_NUMA */
+
+#ifdef CONFIG_NUMA
+/* Free memory allocated for various sched_group structures */
+static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
+{
+       int cpu, i;
+
+       for_each_cpu_mask_nr(cpu, *cpu_map) {
+               struct sched_group **sched_group_nodes
+                       = sched_group_nodes_bycpu[cpu];
+
+               if (!sched_group_nodes)
+                       continue;
+
+               for (i = 0; i < nr_node_ids; i++) {
+                       struct sched_group *oldsg, *sg = sched_group_nodes[i];
+
+                       *nodemask = node_to_cpumask(i);
+                       cpus_and(*nodemask, *nodemask, *cpu_map);
+                       if (cpus_empty(*nodemask))
+                               continue;
+
+                       if (sg == NULL)
+                               continue;
+                       sg = sg->next;
+next_sg:
+                       oldsg = sg;
+                       sg = sg->next;
+                       kfree(oldsg);
+                       if (oldsg != sched_group_nodes[i])
+                               goto next_sg;
+               }
+               kfree(sched_group_nodes);
+               sched_group_nodes_bycpu[cpu] = NULL;
+       }
+}
+#else /* !CONFIG_NUMA */
+static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
+{
+}
+#endif /* CONFIG_NUMA */
+
+/*
+ * Initialize sched groups cpu_power.
+ *
+ * cpu_power indicates the capacity of sched group, which is used while
+ * distributing the load between different sched groups in a sched domain.
+ * Typically cpu_power for all the groups in a sched domain will be same unless
+ * there are asymmetries in the topology. If there are asymmetries, group
+ * having more cpu_power will pickup more load compared to the group having
+ * less cpu_power.
+ *
+ * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
+ * the maximum number of tasks a group can handle in the presence of other idle
+ * or lightly loaded groups in the same sched domain.
+ */
+static void init_sched_groups_power(int cpu, struct sched_domain *sd)
+{
+       struct sched_domain *child;
+       struct sched_group *group;
+
+       WARN_ON(!sd || !sd->groups);
+
+       if (cpu != first_cpu(sd->groups->cpumask))
+               return;
+
+       child = sd->child;
+
+       sd->groups->__cpu_power = 0;
+
+       /*
+        * For perf policy, if the groups in child domain share resources
+        * (for example cores sharing some portions of the cache hierarchy
+        * or SMT), then set this domain groups cpu_power such that each group
+        * can handle only one task, when there are other idle groups in the
+        * same sched domain.
+        */
+       if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
+                      (child->flags &
+                       (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
+               sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
+               return;
+       }
+
+       /*
+        * add cpu_power of each child group to this groups cpu_power
+        */
+       group = child->groups;
+       do {
+               sg_inc_cpu_power(sd->groups, group->__cpu_power);
+               group = group->next;
+       } while (group != child->groups);
+}
+
+/*
+ * Initializers for schedule domains
+ * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
+ */
+
+#define        SD_INIT(sd, type)       sd_init_##type(sd)
+#define SD_INIT_FUNC(type)     \
+static noinline void sd_init_##type(struct sched_domain *sd)   \
+{                                                              \
+       memset(sd, 0, sizeof(*sd));                             \
+       *sd = SD_##type##_INIT;                                 \
+       sd->level = SD_LV_##type;                               \
+}
+
+SD_INIT_FUNC(CPU)
+#ifdef CONFIG_NUMA
+ SD_INIT_FUNC(ALLNODES)
+ SD_INIT_FUNC(NODE)
+#endif
+#ifdef CONFIG_SCHED_SMT
+ SD_INIT_FUNC(SIBLING)
+#endif
+#ifdef CONFIG_SCHED_MC
+ SD_INIT_FUNC(MC)
+#endif
+
+/*
+ * To minimize stack usage kmalloc room for cpumasks and share the
+ * space as the usage in build_sched_domains() dictates.  Used only
+ * if the amount of space is significant.
+ */
+struct allmasks {
+       cpumask_t tmpmask;                      /* make this one first */
+       union {
+               cpumask_t nodemask;
+               cpumask_t this_sibling_map;
+               cpumask_t this_core_map;
+       };
+       cpumask_t send_covered;
+
+#ifdef CONFIG_NUMA
+       cpumask_t domainspan;
+       cpumask_t covered;
+       cpumask_t notcovered;
+#endif
+};
+
+#if    NR_CPUS > 128
+#define        SCHED_CPUMASK_ALLOC             1
+#define        SCHED_CPUMASK_FREE(v)           kfree(v)
+#define        SCHED_CPUMASK_DECLARE(v)        struct allmasks *v
+#else
+#define        SCHED_CPUMASK_ALLOC             0
+#define        SCHED_CPUMASK_FREE(v)
+#define        SCHED_CPUMASK_DECLARE(v)        struct allmasks _v, *v = &_v
+#endif
+
+#define        SCHED_CPUMASK_VAR(v, a)         cpumask_t *v = (cpumask_t *) \
+                       ((unsigned long)(a) + offsetof(struct allmasks, v))
+
+static int default_relax_domain_level = -1;
+
+static int __init setup_relax_domain_level(char *str)
+{
+       unsigned long val;
+
+       val = simple_strtoul(str, NULL, 0);
+       if (val < SD_LV_MAX)
+               default_relax_domain_level = val;
+
+       return 1;
+}
+__setup("relax_domain_level=", setup_relax_domain_level);
+
+static void set_domain_attribute(struct sched_domain *sd,
+                                struct sched_domain_attr *attr)
+{
+       int request;
+
+       if (!attr || attr->relax_domain_level < 0) {
+               if (default_relax_domain_level < 0)
+                       return;
+               else
+                       request = default_relax_domain_level;
+       } else
+               request = attr->relax_domain_level;
+       if (request < sd->level) {
+               /* turn off idle balance on this domain */
+               sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
+       } else {
+               /* turn on idle balance on this domain */
+               sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
+       }
+}
+
+/*
+ * Build sched domains for a given set of cpus and attach the sched domains
+ * to the individual cpus
+ */
+static int __build_sched_domains(const cpumask_t *cpu_map,
+                                struct sched_domain_attr *attr)
+{
+       int i;
+       struct root_domain *rd;
+       SCHED_CPUMASK_DECLARE(allmasks);
+       cpumask_t *tmpmask;
+#ifdef CONFIG_NUMA
+       struct sched_group **sched_group_nodes = NULL;
+       int sd_allnodes = 0;
+
+       /*
+        * Allocate the per-node list of sched groups
+        */
+       sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
+                                   GFP_KERNEL);
+       if (!sched_group_nodes) {
+               printk(KERN_WARNING "Can not alloc sched group node list\n");
+               return -ENOMEM;
+       }
+#endif
+
+       rd = alloc_rootdomain();
+       if (!rd) {
+               printk(KERN_WARNING "Cannot alloc root domain\n");
+#ifdef CONFIG_NUMA
+               kfree(sched_group_nodes);
+#endif
+               return -ENOMEM;
+       }
+
+#if SCHED_CPUMASK_ALLOC
+       /* get space for all scratch cpumask variables */
+       allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL);
+       if (!allmasks) {
+               printk(KERN_WARNING "Cannot alloc cpumask array\n");
+               kfree(rd);
+#ifdef CONFIG_NUMA
+               kfree(sched_group_nodes);
+#endif
+               return -ENOMEM;
+       }
+#endif
+       tmpmask = (cpumask_t *)allmasks;
+
+
+#ifdef CONFIG_NUMA
+       sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
+#endif
+
+       /*
+        * Set up domains for cpus specified by the cpu_map.
+        */
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               struct sched_domain *sd = NULL, *p;
+               SCHED_CPUMASK_VAR(nodemask, allmasks);
+
+               *nodemask = node_to_cpumask(cpu_to_node(i));
+               cpus_and(*nodemask, *nodemask, *cpu_map);
+
+#ifdef CONFIG_NUMA
+               if (cpus_weight(*cpu_map) >
+                               SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
+                       sd = &per_cpu(allnodes_domains, i);
+                       SD_INIT(sd, ALLNODES);
+                       set_domain_attribute(sd, attr);
+                       sd->span = *cpu_map;
+                       cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
+                       p = sd;
+                       sd_allnodes = 1;
+               } else
+                       p = NULL;
+
+               sd = &per_cpu(node_domains, i);
+               SD_INIT(sd, NODE);
+               set_domain_attribute(sd, attr);
+               sched_domain_node_span(cpu_to_node(i), &sd->span);
+               sd->parent = p;
+               if (p)
+                       p->child = sd;
+               cpus_and(sd->span, sd->span, *cpu_map);
+#endif
+
+               p = sd;
+               sd = &per_cpu(phys_domains, i);
+               SD_INIT(sd, CPU);
+               set_domain_attribute(sd, attr);
+               sd->span = *nodemask;
+               sd->parent = p;
+               if (p)
+                       p->child = sd;
+               cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
+
+#ifdef CONFIG_SCHED_MC
+               p = sd;
+               sd = &per_cpu(core_domains, i);
+               SD_INIT(sd, MC);
+               set_domain_attribute(sd, attr);
+               sd->span = cpu_coregroup_map(i);
+               cpus_and(sd->span, sd->span, *cpu_map);
+               sd->parent = p;
+               p->child = sd;
+               cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
+#endif
+
+#ifdef CONFIG_SCHED_SMT
+               p = sd;
+               sd = &per_cpu(cpu_domains, i);
+               SD_INIT(sd, SIBLING);
+               set_domain_attribute(sd, attr);
+               sd->span = per_cpu(cpu_sibling_map, i);
+               cpus_and(sd->span, sd->span, *cpu_map);
+               sd->parent = p;
+               p->child = sd;
+               cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
+#endif
+       }
+
+#ifdef CONFIG_SCHED_SMT
+       /* Set up CPU (sibling) groups */
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               SCHED_CPUMASK_VAR(this_sibling_map, allmasks);
+               SCHED_CPUMASK_VAR(send_covered, allmasks);
+
+               *this_sibling_map = per_cpu(cpu_sibling_map, i);
+               cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map);
+               if (i != first_cpu(*this_sibling_map))
+                       continue;
+
+               init_sched_build_groups(this_sibling_map, cpu_map,
+                                       &cpu_to_cpu_group,
+                                       send_covered, tmpmask);
+       }
+#endif
+
+#ifdef CONFIG_SCHED_MC
+       /* Set up multi-core groups */
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               SCHED_CPUMASK_VAR(this_core_map, allmasks);
+               SCHED_CPUMASK_VAR(send_covered, allmasks);
+
+               *this_core_map = cpu_coregroup_map(i);
+               cpus_and(*this_core_map, *this_core_map, *cpu_map);
+               if (i != first_cpu(*this_core_map))
+                       continue;
+
+               init_sched_build_groups(this_core_map, cpu_map,
+                                       &cpu_to_core_group,
+                                       send_covered, tmpmask);
+       }
+#endif
+
+       /* Set up physical groups */
+       for (i = 0; i < nr_node_ids; i++) {
+               SCHED_CPUMASK_VAR(nodemask, allmasks);
+               SCHED_CPUMASK_VAR(send_covered, allmasks);
+
+               *nodemask = node_to_cpumask(i);
+               cpus_and(*nodemask, *nodemask, *cpu_map);
+               if (cpus_empty(*nodemask))
+                       continue;
+
+               init_sched_build_groups(nodemask, cpu_map,
+                                       &cpu_to_phys_group,
+                                       send_covered, tmpmask);
+       }
+
+#ifdef CONFIG_NUMA
+       /* Set up node groups */
+       if (sd_allnodes) {
+               SCHED_CPUMASK_VAR(send_covered, allmasks);
+
+               init_sched_build_groups(cpu_map, cpu_map,
+                                       &cpu_to_allnodes_group,
+                                       send_covered, tmpmask);
+       }
+
+       for (i = 0; i < nr_node_ids; i++) {
+               /* Set up node groups */
+               struct sched_group *sg, *prev;
+               SCHED_CPUMASK_VAR(nodemask, allmasks);
+               SCHED_CPUMASK_VAR(domainspan, allmasks);
+               SCHED_CPUMASK_VAR(covered, allmasks);
+               int j;
+
+               *nodemask = node_to_cpumask(i);
+               cpus_clear(*covered);
+
+               cpus_and(*nodemask, *nodemask, *cpu_map);
+               if (cpus_empty(*nodemask)) {
+                       sched_group_nodes[i] = NULL;
+                       continue;
+               }
+
+               sched_domain_node_span(i, domainspan);
+               cpus_and(*domainspan, *domainspan, *cpu_map);
+
+               sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
+               if (!sg) {
+                       printk(KERN_WARNING "Can not alloc domain group for "
+                               "node %d\n", i);
+                       goto error;
+               }
+               sched_group_nodes[i] = sg;
+               for_each_cpu_mask_nr(j, *nodemask) {
+                       struct sched_domain *sd;
+
+                       sd = &per_cpu(node_domains, j);
+                       sd->groups = sg;
+               }
+               sg->__cpu_power = 0;
+               sg->cpumask = *nodemask;
+               sg->next = sg;
+               cpus_or(*covered, *covered, *nodemask);
+               prev = sg;
+
+               for (j = 0; j < nr_node_ids; j++) {
+                       SCHED_CPUMASK_VAR(notcovered, allmasks);
+                       int n = (i + j) % nr_node_ids;
+                       node_to_cpumask_ptr(pnodemask, n);
+
+                       cpus_complement(*notcovered, *covered);
+                       cpus_and(*tmpmask, *notcovered, *cpu_map);
+                       cpus_and(*tmpmask, *tmpmask, *domainspan);
+                       if (cpus_empty(*tmpmask))
+                               break;
+
+                       cpus_and(*tmpmask, *tmpmask, *pnodemask);
+                       if (cpus_empty(*tmpmask))
+                               continue;
+
+                       sg = kmalloc_node(sizeof(struct sched_group),
+                                         GFP_KERNEL, i);
+                       if (!sg) {
+                               printk(KERN_WARNING
+                               "Can not alloc domain group for node %d\n", j);
+                               goto error;
+                       }
+                       sg->__cpu_power = 0;
+                       sg->cpumask = *tmpmask;
+                       sg->next = prev->next;
+                       cpus_or(*covered, *covered, *tmpmask);
+                       prev->next = sg;
+                       prev = sg;
+               }
+       }
+#endif
+
+       /* Calculate CPU power for physical packages and nodes */
+#ifdef CONFIG_SCHED_SMT
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               struct sched_domain *sd = &per_cpu(cpu_domains, i);
+
+               init_sched_groups_power(i, sd);
+       }
+#endif
+#ifdef CONFIG_SCHED_MC
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               struct sched_domain *sd = &per_cpu(core_domains, i);
+
+               init_sched_groups_power(i, sd);
+       }
+#endif
+
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               struct sched_domain *sd = &per_cpu(phys_domains, i);
+
+               init_sched_groups_power(i, sd);
+       }
+
+#ifdef CONFIG_NUMA
+       for (i = 0; i < nr_node_ids; i++)
+               init_numa_sched_groups_power(sched_group_nodes[i]);
+
+       if (sd_allnodes) {
+               struct sched_group *sg;
+
+               cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg,
+                                                               tmpmask);
+               init_numa_sched_groups_power(sg);
+       }
+#endif
+
+       /* Attach the domains */
+       for_each_cpu_mask_nr(i, *cpu_map) {
+               struct sched_domain *sd;
+#ifdef CONFIG_SCHED_SMT
+               sd = &per_cpu(cpu_domains, i);
+#elif defined(CONFIG_SCHED_MC)
+               sd = &per_cpu(core_domains, i);
+#else
+               sd = &per_cpu(phys_domains, i);
+#endif
+               cpu_attach_domain(sd, rd, i);
+       }
+
+       SCHED_CPUMASK_FREE((void *)allmasks);
+       return 0;
+
+#ifdef CONFIG_NUMA
+error:
+       free_sched_groups(cpu_map, tmpmask);
+       SCHED_CPUMASK_FREE((void *)allmasks);
+       return -ENOMEM;
+#endif
+}
+
+static int build_sched_domains(const cpumask_t *cpu_map)
+{
+       return __build_sched_domains(cpu_map, NULL);
+}
+
+static cpumask_t *doms_cur;    /* current sched domains */
+static int ndoms_cur;          /* number of sched domains in 'doms_cur' */
+static struct sched_domain_attr *dattr_cur;
+                               /* attribues of custom domains in 'doms_cur' */
+
+/*
+ * Special case: If a kmalloc of a doms_cur partition (array of
+ * cpumask_t) fails, then fallback to a single sched domain,
+ * as determined by the single cpumask_t fallback_doms.
+ */
+static cpumask_t fallback_doms;
+
+void __attribute__((weak)) arch_update_cpu_topology(void)
+{
+}
+
+/*
+ * Set up scheduler domains and groups. Callers must hold the hotplug lock.
+ * For now this just excludes isolated cpus, but could be used to
+ * exclude other special cases in the future.
+ */
+static int arch_init_sched_domains(const cpumask_t *cpu_map)
+{
+       int err;
+
+       arch_update_cpu_topology();
+       ndoms_cur = 1;
+       doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
+       if (!doms_cur)
+               doms_cur = &fallback_doms;
+       cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
+       dattr_cur = NULL;
+       err = build_sched_domains(doms_cur);
+       register_sched_domain_sysctl();
+
+       return err;
+}
+
+static void arch_destroy_sched_domains(const cpumask_t *cpu_map,
+                                      cpumask_t *tmpmask)
+{
+       free_sched_groups(cpu_map, tmpmask);
+}
+
+/*
+ * Detach sched domains from a group of cpus specified in cpu_map
+ * These cpus will now be attached to the NULL domain
+ */
+static void detach_destroy_domains(const cpumask_t *cpu_map)
+{
+       cpumask_t tmpmask;
+       int i;
+
+       unregister_sched_domain_sysctl();
+
+       for_each_cpu_mask_nr(i, *cpu_map)
+               cpu_attach_domain(NULL, &def_root_domain, i);
+       synchronize_sched();
+       arch_destroy_sched_domains(cpu_map, &tmpmask);
+}
+
+/* handle null as "default" */
+static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
+                       struct sched_domain_attr *new, int idx_new)
+{
+       struct sched_domain_attr tmp;
+
+       /* fast path */
+       if (!new && !cur)
+               return 1;
+
+       tmp = SD_ATTR_INIT;
+       return !memcmp(cur ? (cur + idx_cur) : &tmp,
+                       new ? (new + idx_new) : &tmp,
+                       sizeof(struct sched_domain_attr));
+}
+
+/*
+ * Partition sched domains as specified by the 'ndoms_new'
+ * cpumasks in the array doms_new[] of cpumasks. This compares
+ * doms_new[] to the current sched domain partitioning, doms_cur[].
+ * It destroys each deleted domain and builds each new domain.
+ *
+ * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
+ * The masks don't intersect (don't overlap.) We should setup one
+ * sched domain for each mask. CPUs not in any of the cpumasks will
+ * not be load balanced. If the same cpumask appears both in the
+ * current 'doms_cur' domains and in the new 'doms_new', we can leave
+ * it as it is.
+ *
+ * The passed in 'doms_new' should be kmalloc'd. This routine takes
+ * ownership of it and will kfree it when done with it. If the caller
+ * failed the kmalloc call, then it can pass in doms_new == NULL &&
+ * ndoms_new == 1, and partition_sched_domains() will fallback to
+ * the single partition 'fallback_doms', it also forces the domains
+ * to be rebuilt.
+ *
+ * If doms_new == NULL it will be replaced with cpu_online_map.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
+ *
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
+                            struct sched_domain_attr *dattr_new)
+{
+       int i, j, n;
+
+       mutex_lock(&sched_domains_mutex);
+
+       /* always unregister in case we don't destroy any domains */
+       unregister_sched_domain_sysctl();
+
+       n = doms_new ? ndoms_new : 0;
+
+       /* Destroy deleted domains */
+       for (i = 0; i < ndoms_cur; i++) {
+               for (j = 0; j < n; j++) {
+                       if (cpus_equal(doms_cur[i], doms_new[j])
+                           && dattrs_equal(dattr_cur, i, dattr_new, j))
+                               goto match1;
+               }
+               /* no match - a current sched domain not in new doms_new[] */
+               detach_destroy_domains(doms_cur + i);
+match1:
+               ;
+       }
+
+       if (doms_new == NULL) {
+               ndoms_cur = 0;
+               doms_new = &fallback_doms;
+               cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
+               dattr_new = NULL;
+       }
+
+       /* Build new domains */
+       for (i = 0; i < ndoms_new; i++) {
+               for (j = 0; j < ndoms_cur; j++) {
+                       if (cpus_equal(doms_new[i], doms_cur[j])
+                           && dattrs_equal(dattr_new, i, dattr_cur, j))
+                               goto match2;
+               }
+               /* no match - add a new doms_new */
+               __build_sched_domains(doms_new + i,
+                                       dattr_new ? dattr_new + i : NULL);
+match2:
+               ;
+       }
+
+       /* Remember the new sched domains */
+       if (doms_cur != &fallback_doms)
+               kfree(doms_cur);
+       kfree(dattr_cur);       /* kfree(NULL) is safe */
+       doms_cur = doms_new;
+       dattr_cur = dattr_new;
+       ndoms_cur = ndoms_new;
+
+       register_sched_domain_sysctl();
+
+       mutex_unlock(&sched_domains_mutex);
+}
+
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+int arch_reinit_sched_domains(void)
+{
+       get_online_cpus();
+
+       /* Destroy domains first to force the rebuild */
+       partition_sched_domains(0, NULL, NULL);
+
+       rebuild_sched_domains();
+       put_online_cpus();
+
+       return 0;
+}
+
+static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
+{
+       int ret;
+
+       if (buf[0] != '0' && buf[0] != '1')
+               return -EINVAL;
+
+       if (smt)
+               sched_smt_power_savings = (buf[0] == '1');
+       else
+               sched_mc_power_savings = (buf[0] == '1');
+
+       ret = arch_reinit_sched_domains();
+
+       return ret ? ret : count;
+}
+
+#ifdef CONFIG_SCHED_MC
+static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
+                                          char *page)
+{
+       return sprintf(page, "%u\n", sched_mc_power_savings);
+}
+static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
+                                           const char *buf, size_t count)
+{
+       return sched_power_savings_store(buf, count, 0);
+}
+static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
+                        sched_mc_power_savings_show,
+                        sched_mc_power_savings_store);
+#endif
+
+#ifdef CONFIG_SCHED_SMT
+static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
+                                           char *page)
+{
+       return sprintf(page, "%u\n", sched_smt_power_savings);
+}
+static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
+                                            const char *buf, size_t count)
+{
+       return sched_power_savings_store(buf, count, 1);
+}
+static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
+                  sched_smt_power_savings_show,
+                  sched_smt_power_savings_store);
+#endif
+
+int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
+{
+       int err = 0;
+
+#ifdef CONFIG_SCHED_SMT
+       if (smt_capable())
+               err = sysfs_create_file(&cls->kset.kobj,
+                                       &attr_sched_smt_power_savings.attr);
+#endif
+#ifdef CONFIG_SCHED_MC
+       if (!err && mc_capable())
+               err = sysfs_create_file(&cls->kset.kobj,
+                                       &attr_sched_mc_power_savings.attr);
+#endif
+       return err;
+}
+#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+
+#ifndef CONFIG_CPUSETS
+/*
+ * Add online and remove offline CPUs from the scheduler domains.
+ * When cpusets are enabled they take over this function.
+ */
+static int update_sched_domains(struct notifier_block *nfb,
+                               unsigned long action, void *hcpu)
+{
+       switch (action) {
+       case CPU_ONLINE:
+       case CPU_ONLINE_FROZEN:
+       case CPU_DEAD:
+       case CPU_DEAD_FROZEN:
+               partition_sched_domains(1, NULL, NULL);
+               return NOTIFY_OK;
+
+       default:
+               return NOTIFY_DONE;
+       }
+}
+#endif
+
+static int update_runtime(struct notifier_block *nfb,
+                               unsigned long action, void *hcpu)
+{
+       int cpu = (int)(long)hcpu;
+
+       switch (action) {
+       case CPU_DOWN_PREPARE:
+       case CPU_DOWN_PREPARE_FROZEN:
+               disable_runtime(cpu_rq(cpu));
+               return NOTIFY_OK;
+
+       case CPU_DOWN_FAILED:
+       case CPU_DOWN_FAILED_FROZEN:
+       case CPU_ONLINE:
+       case CPU_ONLINE_FROZEN:
+               enable_runtime(cpu_rq(cpu));
+               return NOTIFY_OK;
+
+       default:
+               return NOTIFY_DONE;
+       }
+}
+
+void __init sched_init_smp(void)
+{
+       cpumask_t non_isolated_cpus;
+
+#if defined(CONFIG_NUMA)
+       sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
+                                                               GFP_KERNEL);
+       BUG_ON(sched_group_nodes_bycpu == NULL);
+#endif
+       get_online_cpus();
+       mutex_lock(&sched_domains_mutex);
+       arch_init_sched_domains(&cpu_online_map);
+       cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
+       if (cpus_empty(non_isolated_cpus))
+               cpu_set(smp_processor_id(), non_isolated_cpus);
+       mutex_unlock(&sched_domains_mutex);
+       put_online_cpus();
+
+#ifndef CONFIG_CPUSETS
+       /* XXX: Theoretical race here - CPU may be hotplugged now */
+       hotcpu_notifier(update_sched_domains, 0);
+#endif
+
+       /* RT runtime code needs to handle some hotplug events */
+       hotcpu_notifier(update_runtime, 0);
+
+       init_hrtick();
+
+       /* Move init over to a non-isolated CPU */
+       if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
+               BUG();
+       sched_init_granularity();
+}
+#else
+void __init sched_init_smp(void)
+{
+       sched_init_granularity();
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+       return in_lock_functions(addr) ||
+               (addr >= (unsigned long)__sched_text_start
+               && addr < (unsigned long)__sched_text_end);
+}
+
+static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
+{
+       cfs_rq->tasks_timeline = RB_ROOT;
+       INIT_LIST_HEAD(&cfs_rq->tasks);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       cfs_rq->rq = rq;
+#endif
+       cfs_rq->min_vruntime = (u64)(-(1LL << 20));
+}
+
+static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
+{
+       struct rt_prio_array *array;
+       int i;
+
+       array = &rt_rq->active;
+       for (i = 0; i < MAX_RT_PRIO; i++) {
+               INIT_LIST_HEAD(array->queue + i);
+               __clear_bit(i, array->bitmap);
+       }
+       /* delimiter for bitsearch: */
+       __set_bit(MAX_RT_PRIO, array->bitmap);
+
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+       rt_rq->highest_prio = MAX_RT_PRIO;
+#endif
+#ifdef CONFIG_SMP
+       rt_rq->rt_nr_migratory = 0;
+       rt_rq->overloaded = 0;
+#endif
+
+       rt_rq->rt_time = 0;
+       rt_rq->rt_throttled = 0;
+       rt_rq->rt_runtime = 0;
+       spin_lock_init(&rt_rq->rt_runtime_lock);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+       rt_rq->rt_nr_boosted = 0;
+       rt_rq->rq = rq;
+#endif
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+                               struct sched_entity *se, int cpu, int add,
+                               struct sched_entity *parent)
+{
+       struct rq *rq = cpu_rq(cpu);
+       tg->cfs_rq[cpu] = cfs_rq;
+       init_cfs_rq(cfs_rq, rq);
+       cfs_rq->tg = tg;
+       if (add)
+               list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+       tg->se[cpu] = se;
+       /* se could be NULL for init_task_group */
+       if (!se)
+               return;
+
+       if (!parent)
+               se->cfs_rq = &rq->cfs;
+       else
+               se->cfs_rq = parent->my_q;
+
+       se->my_q = cfs_rq;
+       se->load.weight = tg->shares;
+       se->load.inv_weight = 0;
+       se->parent = parent;
+}
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+               struct sched_rt_entity *rt_se, int cpu, int add,
+               struct sched_rt_entity *parent)
+{
+       struct rq *rq = cpu_rq(cpu);
+
+       tg->rt_rq[cpu] = rt_rq;
+       init_rt_rq(rt_rq, rq);
+       rt_rq->tg = tg;
+       rt_rq->rt_se = rt_se;
+       rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
+       if (add)
+               list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
+
+       tg->rt_se[cpu] = rt_se;
+       if (!rt_se)
+               return;
+
+       if (!parent)
+               rt_se->rt_rq = &rq->rt;
+       else
+               rt_se->rt_rq = parent->my_q;
+
+       rt_se->my_q = rt_rq;
+       rt_se->parent = parent;
+       INIT_LIST_HEAD(&rt_se->run_list);
+}
+#endif
+
+void __init sched_init(void)
+{
+       int i, j;
+       unsigned long alloc_size = 0, ptr;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       alloc_size += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+       alloc_size += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+#ifdef CONFIG_USER_SCHED
+       alloc_size *= 2;
+#endif
+       /*
+        * As sched_init() is called before page_alloc is setup,
+        * we use alloc_bootmem().
+        */
+       if (alloc_size) {
+               ptr = (unsigned long)alloc_bootmem(alloc_size);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+               init_task_group.se = (struct sched_entity **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+               init_task_group.cfs_rq = (struct cfs_rq **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+#ifdef CONFIG_USER_SCHED
+               root_task_group.se = (struct sched_entity **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+               root_task_group.cfs_rq = (struct cfs_rq **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+#endif /* CONFIG_USER_SCHED */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+#ifdef CONFIG_RT_GROUP_SCHED
+               init_task_group.rt_se = (struct sched_rt_entity **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+               init_task_group.rt_rq = (struct rt_rq **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+#ifdef CONFIG_USER_SCHED
+               root_task_group.rt_se = (struct sched_rt_entity **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+
+               root_task_group.rt_rq = (struct rt_rq **)ptr;
+               ptr += nr_cpu_ids * sizeof(void **);
+#endif /* CONFIG_USER_SCHED */
+#endif /* CONFIG_RT_GROUP_SCHED */
+       }
+
+#ifdef CONFIG_SMP
+       init_defrootdomain();
+#endif
+
+       init_rt_bandwidth(&def_rt_bandwidth,
+                       global_rt_period(), global_rt_runtime());
+
+#ifdef CONFIG_RT_GROUP_SCHED
+       init_rt_bandwidth(&init_task_group.rt_bandwidth,
+                       global_rt_period(), global_rt_runtime());
+#ifdef CONFIG_USER_SCHED
+       init_rt_bandwidth(&root_task_group.rt_bandwidth,
+                       global_rt_period(), RUNTIME_INF);
+#endif /* CONFIG_USER_SCHED */
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_GROUP_SCHED
+       list_add(&init_task_group.list, &task_groups);
+       INIT_LIST_HEAD(&init_task_group.children);
+
+#ifdef CONFIG_USER_SCHED
+       INIT_LIST_HEAD(&root_task_group.children);
+       init_task_group.parent = &root_task_group;
+       list_add(&init_task_group.siblings, &root_task_group.children);
+#endif /* CONFIG_USER_SCHED */
+#endif /* CONFIG_GROUP_SCHED */
+
+       for_each_possible_cpu(i) {
+               struct rq *rq;
+
+               rq = cpu_rq(i);
+               spin_lock_init(&rq->lock);
+               rq->nr_running = 0;
+               init_cfs_rq(&rq->cfs, rq);
+               init_rt_rq(&rq->rt, rq);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+               init_task_group.shares = init_task_group_load;
+               INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
+#ifdef CONFIG_CGROUP_SCHED
+               /*
+                * How much cpu bandwidth does init_task_group get?
+                *
+                * In case of task-groups formed thr' the cgroup filesystem, it
+                * gets 100% of the cpu resources in the system. This overall
+                * system cpu resource is divided among the tasks of
+                * init_task_group and its child task-groups in a fair manner,
+                * based on each entity's (task or task-group's) weight
+                * (se->load.weight).
+                *
+                * In other words, if init_task_group has 10 tasks of weight
+                * 1024) and two child groups A0 and A1 (of weight 1024 each),
+                * then A0's share of the cpu resource is:
+                *
+                *      A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
+                *
+                * We achieve this by letting init_task_group's tasks sit
+                * directly in rq->cfs (i.e init_task_group->se[] = NULL).
+                */
+               init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
+#elif defined CONFIG_USER_SCHED
+               root_task_group.shares = NICE_0_LOAD;
+               init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
+               /*
+                * In case of task-groups formed thr' the user id of tasks,
+                * init_task_group represents tasks belonging to root user.
+                * Hence it forms a sibling of all subsequent groups formed.
+                * In this case, init_task_group gets only a fraction of overall
+                * system cpu resource, based on the weight assigned to root
+                * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
+                * by letting tasks of init_task_group sit in a separate cfs_rq
+                * (init_cfs_rq) and having one entity represent this group of
+                * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
+                */
+               init_tg_cfs_entry(&init_task_group,
+                               &per_cpu(init_cfs_rq, i),
+                               &per_cpu(init_sched_entity, i), i, 1,
+                               root_task_group.se[i]);
+
+#endif
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+               rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
+#ifdef CONFIG_RT_GROUP_SCHED
+               INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
+#ifdef CONFIG_CGROUP_SCHED
+               init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
+#elif defined CONFIG_USER_SCHED
+               init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
+               init_tg_rt_entry(&init_task_group,
+                               &per_cpu(init_rt_rq, i),
+                               &per_cpu(init_sched_rt_entity, i), i, 1,
+                               root_task_group.rt_se[i]);
+#endif
+#endif
+
+               for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
+                       rq->cpu_load[j] = 0;
+#ifdef CONFIG_SMP
+               rq->sd = NULL;
+               rq->rd = NULL;
+               rq->active_balance = 0;
+               rq->next_balance = jiffies;
+               rq->push_cpu = 0;
+               rq->cpu = i;
+               rq->online = 0;
+               rq->migration_thread = NULL;
+               INIT_LIST_HEAD(&rq->migration_queue);
+               rq_attach_root(rq, &def_root_domain);
+#endif
+               init_rq_hrtick(rq);
+               atomic_set(&rq->nr_iowait, 0);
+       }
+
+       set_load_weight(&init_task);
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+       INIT_HLIST_HEAD(&init_task.preempt_notifiers);
+#endif
+
+#ifdef CONFIG_SMP
+       open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
+#endif
+
+#ifdef CONFIG_RT_MUTEXES
+       plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
+#endif
+
+       /*
+        * The boot idle thread does lazy MMU switching as well:
+        */
+       atomic_inc(&init_mm.mm_count);
+       enter_lazy_tlb(&init_mm, current);
+
+       /*
+        * Make us the idle thread. Technically, schedule() should not be
+        * called from this thread, however somewhere below it might be,
+        * but because we are the idle thread, we just pick up running again
+        * when this runqueue becomes "idle".
+        */
+       init_idle(current, smp_processor_id());
+       /*
+        * During early bootup we pretend to be a normal task:
+        */
+       current->sched_class = &fair_sched_class;
+
+       scheduler_running = 1;
+}
+
+#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
+void __might_sleep(char *file, int line)
+{
+#ifdef in_atomic
+       static unsigned long prev_jiffy;        /* ratelimiting */
+
+       if ((in_atomic() || irqs_disabled()) &&
+           system_state == SYSTEM_RUNNING && !oops_in_progress) {
+               if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+                       return;
+               prev_jiffy = jiffies;
+               printk(KERN_ERR "BUG: sleeping function called from invalid"
+                               " context at %s:%d\n", file, line);
+               printk("in_atomic():%d, irqs_disabled():%d\n",
+                       in_atomic(), irqs_disabled());
+               debug_show_held_locks(current);
+               if (irqs_disabled())
+                       print_irqtrace_events(current);
+               dump_stack();
+       }
+#endif
+}
+EXPORT_SYMBOL(__might_sleep);
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void normalize_task(struct rq *rq, struct task_struct *p)
+{
+       int on_rq;
+
+       update_rq_clock(rq);
+       on_rq = p->se.on_rq;
+       if (on_rq)
+               deactivate_task(rq, p, 0);
+       __setscheduler(rq, p, SCHED_NORMAL, 0);
+       if (on_rq) {
+               activate_task(rq, p, 0);
+               resched_task(rq->curr);
+       }
+}
+
+void normalize_rt_tasks(void)
+{
+       struct task_struct *g, *p;
+       unsigned long flags;
+       struct rq *rq;
+
+       read_lock_irqsave(&tasklist_lock, flags);
+       do_each_thread(g, p) {
+               /*
+                * Only normalize user tasks:
+                */
+               if (!p->mm)
+                       continue;
+
+               p->se.exec_start                = 0;
+#ifdef CONFIG_SCHEDSTATS
+               p->se.wait_start                = 0;
+               p->se.sleep_start               = 0;
+               p->se.block_start               = 0;
+#endif
+
+               if (!rt_task(p)) {
+                       /*
+                        * Renice negative nice level userspace
+                        * tasks back to 0:
+                        */
+                       if (TASK_NICE(p) < 0 && p->mm)
+                               set_user_nice(p, 0);
+                       continue;
+               }
+
+               spin_lock(&p->pi_lock);
+               rq = __task_rq_lock(p);
+
+               normalize_task(rq, p);
+
+               __task_rq_unlock(rq);
+               spin_unlock(&p->pi_lock);
+       } while_each_thread(g, p);
+
+       read_unlock_irqrestore(&tasklist_lock, flags);
+}
+
+#endif /* CONFIG_MAGIC_SYSRQ */
+
+#ifdef CONFIG_IA64
+/*
+ * These functions are only useful for the IA64 MCA handling.
+ *
+ * They can only be called when the whole system has been
+ * stopped - every CPU needs to be quiescent, and no scheduling
+ * activity can take place. Using them for anything else would
+ * be a serious bug, and as a result, they aren't even visible
+ * under any other configuration.
+ */
+
+/**
+ * curr_task - return the current task for a given cpu.
+ * @cpu: the processor in question.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+struct task_struct *curr_task(int cpu)
+{
+       return cpu_curr(cpu);
+}
+
+/**
+ * set_curr_task - set the current task for a given cpu.
+ * @cpu: the processor in question.
+ * @p: the task pointer to set.
+ *
+ * Description: This function must only be used when non-maskable interrupts
+ * are serviced on a separate stack. It allows the architecture to switch the
+ * notion of the current task on a cpu in a non-blocking manner. This function
+ * must be called with all CPU's synchronized, and interrupts disabled, the
+ * and caller must save the original value of the current task (see
+ * curr_task() above) and restore that value before reenabling interrupts and
+ * re-starting the system.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+void set_curr_task(int cpu, struct task_struct *p)
+{
+       cpu_curr(cpu) = p;
+}
+
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void free_fair_sched_group(struct task_group *tg)
+{
+       int i;
+
+       for_each_possible_cpu(i) {
+               if (tg->cfs_rq)
+                       kfree(tg->cfs_rq[i]);
+               if (tg->se)
+                       kfree(tg->se[i]);
+       }
+
+       kfree(tg->cfs_rq);
+       kfree(tg->se);
+}
+
+static
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+       struct cfs_rq *cfs_rq;
+       struct sched_entity *se, *parent_se;
+       struct rq *rq;
+       int i;
+
+       tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
+       if (!tg->cfs_rq)
+               goto err;
+       tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
+       if (!tg->se)
+               goto err;
+
+       tg->shares = NICE_0_LOAD;
+
+       for_each_possible_cpu(i) {
+               rq = cpu_rq(i);
+
+               cfs_rq = kmalloc_node(sizeof(struct cfs_rq),
+                               GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+               if (!cfs_rq)
+                       goto err;
+
+               se = kmalloc_node(sizeof(struct sched_entity),
+                               GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+               if (!se)
+                       goto err;
+
+               parent_se = parent ? parent->se[i] : NULL;
+               init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se);
+       }
+
+       return 1;
+
+ err:
+       return 0;
+}
+
+static inline void register_fair_sched_group(struct task_group *tg, int cpu)
+{
+       list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
+                       &cpu_rq(cpu)->leaf_cfs_rq_list);
+}
+
+static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
+{
+       list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
+}
+#else /* !CONFG_FAIR_GROUP_SCHED */
+static inline void free_fair_sched_group(struct task_group *tg)
+{
+}
+
+static inline
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+       return 1;
+}
+
+static inline void register_fair_sched_group(struct task_group *tg, int cpu)
+{
+}
+
+static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
+{
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void free_rt_sched_group(struct task_group *tg)
+{
+       int i;
+
+       destroy_rt_bandwidth(&tg->rt_bandwidth);
+
+       for_each_possible_cpu(i) {
+               if (tg->rt_rq)
+                       kfree(tg->rt_rq[i]);
+               if (tg->rt_se)
+                       kfree(tg->rt_se[i]);
+       }
+
+       kfree(tg->rt_rq);
+       kfree(tg->rt_se);
+}
+
+static
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+       struct rt_rq *rt_rq;
+       struct sched_rt_entity *rt_se, *parent_se;
+       struct rq *rq;
+       int i;
+
+       tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
+       if (!tg->rt_rq)
+               goto err;
+       tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
+       if (!tg->rt_se)
+               goto err;
+
+       init_rt_bandwidth(&tg->rt_bandwidth,
+                       ktime_to_ns(def_rt_bandwidth.rt_period), 0);
+
+       for_each_possible_cpu(i) {
+               rq = cpu_rq(i);
+
+               rt_rq = kmalloc_node(sizeof(struct rt_rq),
+                               GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+               if (!rt_rq)
+                       goto err;
+
+               rt_se = kmalloc_node(sizeof(struct sched_rt_entity),
+                               GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+               if (!rt_se)
+                       goto err;
+
+               parent_se = parent ? parent->rt_se[i] : NULL;
+               init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se);
+       }
+
+       return 1;
+
+ err:
+       return 0;
+}
+
+static inline void register_rt_sched_group(struct task_group *tg, int cpu)
+{
+       list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
+                       &cpu_rq(cpu)->leaf_rt_rq_list);
+}
+
+static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
+{
+       list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
+}
+#else /* !CONFIG_RT_GROUP_SCHED */
+static inline void free_rt_sched_group(struct task_group *tg)
+{
+}
+
+static inline
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+       return 1;
+}
+
+static inline void register_rt_sched_group(struct task_group *tg, int cpu)
+{
+}
+
+static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
+{
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_GROUP_SCHED
+static void free_sched_group(struct task_group *tg)
+{
+       free_fair_sched_group(tg);
+       free_rt_sched_group(tg);
+       kfree(tg);
+}
+
+/* allocate runqueue etc for a new task group */
+struct task_group *sched_create_group(struct task_group *parent)
+{
+       struct task_group *tg;
+       unsigned long flags;
+       int i;
+
+       tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+       if (!tg)
+               return ERR_PTR(-ENOMEM);
+
+       if (!alloc_fair_sched_group(tg, parent))
+               goto err;
+
+       if (!alloc_rt_sched_group(tg, parent))
+               goto err;
+
+       spin_lock_irqsave(&task_group_lock, flags);
+       for_each_possible_cpu(i) {
+               register_fair_sched_group(tg, i);
+               register_rt_sched_group(tg, i);
+       }
+       list_add_rcu(&tg->list, &task_groups);
+
+       WARN_ON(!parent); /* root should already exist */
+
+       tg->parent = parent;
+       INIT_LIST_HEAD(&tg->children);
+       list_add_rcu(&tg->siblings, &parent->children);
+       spin_unlock_irqrestore(&task_group_lock, flags);
+
+       return tg;
+
+err:
+       free_sched_group(tg);
+       return ERR_PTR(-ENOMEM);
+}
+
+/* rcu callback to free various structures associated with a task group */
+static void free_sched_group_rcu(struct rcu_head *rhp)
+{
+       /* now it should be safe to free those cfs_rqs */
+       free_sched_group(container_of(rhp, struct task_group, rcu));
+}
+
+/* Destroy runqueue etc associated with a task group */
+void sched_destroy_group(struct task_group *tg)
+{
+       unsigned long flags;
+       int i;
+
+       spin_lock_irqsave(&task_group_lock, flags);
+       for_each_possible_cpu(i) {
+               unregister_fair_sched_group(tg, i);
+               unregister_rt_sched_group(tg, i);
+       }
+       list_del_rcu(&tg->list);
+       list_del_rcu(&tg->siblings);
+       spin_unlock_irqrestore(&task_group_lock, flags);
+
+       /* wait for possible concurrent references to cfs_rqs complete */
+       call_rcu(&tg->rcu, free_sched_group_rcu);
+}
+
+/* change task's runqueue when it moves between groups.
+ *     The caller of this function should have put the task in its new group
+ *     by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
+ *     reflect its new group.
+ */
+void sched_move_task(struct task_struct *tsk)
+{
+       int on_rq, running;
+       unsigned long flags;
+       struct rq *rq;
+
+       rq = task_rq_lock(tsk, &flags);
+
+       update_rq_clock(rq);
+
+       running = task_current(rq, tsk);
+       on_rq = tsk->se.on_rq;
+
+       if (on_rq)
+               dequeue_task(rq, tsk, 0);
+       if (unlikely(running))
+               tsk->sched_class->put_prev_task(rq, tsk);
+
+       set_task_rq(tsk, task_cpu(tsk));
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       if (tsk->sched_class->moved_group)
+               tsk->sched_class->moved_group(tsk);
+#endif
+
+       if (unlikely(running))
+               tsk->sched_class->set_curr_task(rq);
+       if (on_rq)
+               enqueue_task(rq, tsk, 0);
+
+       task_rq_unlock(rq, &flags);
+}
+#endif /* CONFIG_GROUP_SCHED */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void __set_se_shares(struct sched_entity *se, unsigned long shares)
+{
+       struct cfs_rq *cfs_rq = se->cfs_rq;
+       int on_rq;
+
+       on_rq = se->on_rq;
+       if (on_rq)
+               dequeue_entity(cfs_rq, se, 0);
+
+       se->load.weight = shares;
+       se->load.inv_weight = 0;
+
+       if (on_rq)
+               enqueue_entity(cfs_rq, se, 0);
+}
+
+static void set_se_shares(struct sched_entity *se, unsigned long shares)
+{
+       struct cfs_rq *cfs_rq = se->cfs_rq;
+       struct rq *rq = cfs_rq->rq;
+       unsigned long flags;
+
+       spin_lock_irqsave(&rq->lock, flags);
+       __set_se_shares(se, shares);
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static DEFINE_MUTEX(shares_mutex);
+
+int sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+       int i;
+       unsigned long flags;
+
+       /*
+        * We can't change the weight of the root cgroup.
+        */
+       if (!tg->se[0])
+               return -EINVAL;
+
+       if (shares < MIN_SHARES)
+               shares = MIN_SHARES;
+       else if (shares > MAX_SHARES)
+               shares = MAX_SHARES;
+
+       mutex_lock(&shares_mutex);
+       if (tg->shares == shares)
+               goto done;
+
+       spin_lock_irqsave(&task_group_lock, flags);
+       for_each_possible_cpu(i)
+               unregister_fair_sched_group(tg, i);
+       list_del_rcu(&tg->siblings);
+       spin_unlock_irqrestore(&task_group_lock, flags);
+
+       /* wait for any ongoing reference to this group to finish */
+       synchronize_sched();
+
+       /*
+        * Now we are free to modify the group's share on each cpu
+        * w/o tripping rebalance_share or load_balance_fair.
+        */
+       tg->shares = shares;
+       for_each_possible_cpu(i) {
+               /*
+                * force a rebalance
+                */
+               cfs_rq_set_shares(tg->cfs_rq[i], 0);
+               set_se_shares(tg->se[i], shares);
+       }
+
+       /*
+        * Enable load balance activity on this group, by inserting it back on
+        * each cpu's rq->leaf_cfs_rq_list.
+        */
+       spin_lock_irqsave(&task_group_lock, flags);
+       for_each_possible_cpu(i)
+               register_fair_sched_group(tg, i);
+       list_add_rcu(&tg->siblings, &tg->parent->children);
+       spin_unlock_irqrestore(&task_group_lock, flags);
+done:
+       mutex_unlock(&shares_mutex);
+       return 0;
+}
+
+unsigned long sched_group_shares(struct task_group *tg)
+{
+       return tg->shares;
+}
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+/*
+ * Ensure that the real time constraints are schedulable.
+ */
+static DEFINE_MUTEX(rt_constraints_mutex);
+
+static unsigned long to_ratio(u64 period, u64 runtime)
+{
+       if (runtime == RUNTIME_INF)
+               return 1ULL << 16;
+
+       return div64_u64(runtime << 16, period);
+}
+
+#ifdef CONFIG_CGROUP_SCHED
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
+{
+       struct task_group *tgi, *parent = tg->parent;
+       unsigned long total = 0;
+
+       if (!parent) {
+               if (global_rt_period() < period)
+                       return 0;
+
+               return to_ratio(period, runtime) <
+                       to_ratio(global_rt_period(), global_rt_runtime());
+       }
+
+       if (ktime_to_ns(parent->rt_bandwidth.rt_period) < period)
+               return 0;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(tgi, &parent->children, siblings) {
+               if (tgi == tg)
+                       continue;
+
+               total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
+                               tgi->rt_bandwidth.rt_runtime);
+       }
+       rcu_read_unlock();
+
+       return total + to_ratio(period, runtime) <=
+               to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period),
+                               parent->rt_bandwidth.rt_runtime);
+}
+#elif defined CONFIG_USER_SCHED
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
+{
+       struct task_group *tgi;
+       unsigned long total = 0;
+       unsigned long global_ratio =
+               to_ratio(global_rt_period(), global_rt_runtime());
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(tgi, &task_groups, list) {
+               if (tgi == tg)
+                       continue;
+
+               total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
+                               tgi->rt_bandwidth.rt_runtime);
+       }
+       rcu_read_unlock();
+
+       return total + to_ratio(period, runtime) < global_ratio;
+}
+#endif
+
+/* Must be called with tasklist_lock held */
+static inline int tg_has_rt_tasks(struct task_group *tg)
+{
+       struct task_struct *g, *p;
+       do_each_thread(g, p) {
+               if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
+                       return 1;
+       } while_each_thread(g, p);
+       return 0;
+}
+
+static int tg_set_bandwidth(struct task_group *tg,
+               u64 rt_period, u64 rt_runtime)
+{
+       int i, err = 0;
+
+       mutex_lock(&rt_constraints_mutex);
+       read_lock(&tasklist_lock);
+       if (rt_runtime == 0 && tg_has_rt_tasks(tg)) {
+               err = -EBUSY;
+               goto unlock;
+       }
+       if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
+               err = -EINVAL;
+               goto unlock;
+       }
+
+       spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+       tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
+       tg->rt_bandwidth.rt_runtime = rt_runtime;
+
+       for_each_possible_cpu(i) {
+               struct rt_rq *rt_rq = tg->rt_rq[i];
+
+               spin_lock(&rt_rq->rt_runtime_lock);
+               rt_rq->rt_runtime = rt_runtime;
+               spin_unlock(&rt_rq->rt_runtime_lock);
+       }
+       spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+ unlock:
+       read_unlock(&tasklist_lock);
+       mutex_unlock(&rt_constraints_mutex);
+
+       return err;
+}
+
+int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
+{
+       u64 rt_runtime, rt_period;
+
+       rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+       rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
+       if (rt_runtime_us < 0)
+               rt_runtime = RUNTIME_INF;
+
+       return tg_set_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_runtime(struct task_group *tg)
+{
+       u64 rt_runtime_us;
+
+       if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
+               return -1;
+
+       rt_runtime_us = tg->rt_bandwidth.rt_runtime;
+       do_div(rt_runtime_us, NSEC_PER_USEC);
+       return rt_runtime_us;
+}
+
+int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
+{
+       u64 rt_runtime, rt_period;
+
+       rt_period = (u64)rt_period_us * NSEC_PER_USEC;
+       rt_runtime = tg->rt_bandwidth.rt_runtime;
+
+       if (rt_period == 0)
+               return -EINVAL;
+
+       return tg_set_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_period(struct task_group *tg)
+{
+       u64 rt_period_us;
+
+       rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
+       do_div(rt_period_us, NSEC_PER_USEC);
+       return rt_period_us;
+}
+
+static int sched_rt_global_constraints(void)
+{
+       struct task_group *tg = &root_task_group;
+       u64 rt_runtime, rt_period;
+       int ret = 0;
+
+       if (sysctl_sched_rt_period <= 0)
+               return -EINVAL;
+
+       rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+       rt_runtime = tg->rt_bandwidth.rt_runtime;
+
+       mutex_lock(&rt_constraints_mutex);
+       if (!__rt_schedulable(tg, rt_period, rt_runtime))
+               ret = -EINVAL;
+       mutex_unlock(&rt_constraints_mutex);
+
+       return ret;
+}
+#else /* !CONFIG_RT_GROUP_SCHED */
+static int sched_rt_global_constraints(void)
+{
+       unsigned long flags;
+       int i;
+
+       if (sysctl_sched_rt_period <= 0)
+               return -EINVAL;
+
+       spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
+       for_each_possible_cpu(i) {
+               struct rt_rq *rt_rq = &cpu_rq(i)->rt;
+
+               spin_lock(&rt_rq->rt_runtime_lock);
+               rt_rq->rt_runtime = global_rt_runtime();
+               spin_unlock(&rt_rq->rt_runtime_lock);
+       }
+       spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
+
+       return 0;
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+int sched_rt_handler(struct ctl_table *table, int write,
+               struct file *filp, void __user *buffer, size_t *lenp,
+               loff_t *ppos)
+{
+       int ret;
+       int old_period, old_runtime;
+       static DEFINE_MUTEX(mutex);
+
+       mutex_lock(&mutex);
+       old_period = sysctl_sched_rt_period;
+       old_runtime = sysctl_sched_rt_runtime;
+
+       ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
+
+       if (!ret && write) {
+               ret = sched_rt_global_constraints();
+               if (ret) {
+                       sysctl_sched_rt_period = old_period;
+                       sysctl_sched_rt_runtime = old_runtime;
+               } else {
+                       def_rt_bandwidth.rt_runtime = global_rt_runtime();
+                       def_rt_bandwidth.rt_period =
+                               ns_to_ktime(global_rt_period());
+               }
+       }
+       mutex_unlock(&mutex);
+
+       return ret;
+}
+
+#ifdef CONFIG_CGROUP_SCHED
+
+/* return corresponding task_group object of a cgroup */
+static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
+{
+       return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
+                           struct task_group, css);
+}
+
+static struct cgroup_subsys_state *
+cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+       struct task_group *tg, *parent;
+
+       if (!cgrp->parent) {
+               /* This is early initialization for the top cgroup */
+               init_task_group.css.cgroup = cgrp;
+               return &init_task_group.css;
+       }
+
+       parent = cgroup_tg(cgrp->parent);
+       tg = sched_create_group(parent);
+       if (IS_ERR(tg))
+               return ERR_PTR(-ENOMEM);
+
+       /* Bind the cgroup to task_group object we just created */
+       tg->css.cgroup = cgrp;
+
+       return &tg->css;
+}
+
+static void
+cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+       struct task_group *tg = cgroup_tg(cgrp);
+
+       sched_destroy_group(tg);
+}
+
+static int
+cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
+                     struct task_struct *tsk)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+       /* Don't accept realtime tasks when there is no way for them to run */
+       if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
+               return -EINVAL;
+#else
+       /* We don't support RT-tasks being in separate groups */
+       if (tsk->sched_class != &fair_sched_class)
+               return -EINVAL;
+#endif
+
+       return 0;
+}
+
+static void
+cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
+                       struct cgroup *old_cont, struct task_struct *tsk)
+{
+       sched_move_task(tsk);
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
+                               u64 shareval)
+{
+       return sched_group_set_shares(cgroup_tg(cgrp), shareval);
+}
+
+static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
+{
+       struct task_group *tg = cgroup_tg(cgrp);
+
+       return (u64) tg->shares;
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
+                               s64 val)
+{
+       return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
+}
+
+static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       return sched_group_rt_runtime(cgroup_tg(cgrp));
+}
+
+static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
+               u64 rt_period_us)
+{
+       return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
+}
+
+static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
+{
+       return sched_group_rt_period(cgroup_tg(cgrp));
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+static struct cftype cpu_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       {
+               .name = "shares",
+               .read_u64 = cpu_shares_read_u64,
+               .write_u64 = cpu_shares_write_u64,
+       },
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+       {
+               .name = "rt_runtime_us",
+               .read_s64 = cpu_rt_runtime_read,
+               .write_s64 = cpu_rt_runtime_write,
+       },
+       {
+               .name = "rt_period_us",
+               .read_u64 = cpu_rt_period_read_uint,
+               .write_u64 = cpu_rt_period_write_uint,
+       },
+#endif
+};
+
+static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+       return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
+}
+
+struct cgroup_subsys cpu_cgroup_subsys = {
+       .name           = "cpu",
+       .create         = cpu_cgroup_create,
+       .destroy        = cpu_cgroup_destroy,
+       .can_attach     = cpu_cgroup_can_attach,
+       .attach         = cpu_cgroup_attach,
+       .populate       = cpu_cgroup_populate,
+       .subsys_id      = cpu_cgroup_subsys_id,
+       .early_init     = 1,
+};
+
+#endif /* CONFIG_CGROUP_SCHED */
+
+#ifdef CONFIG_CGROUP_CPUACCT
+
+/*
+ * CPU accounting code for task groups.
+ *
+ * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
+ * (balbir@in.ibm.com).
+ */
+
+/* track cpu usage of a group of tasks */
+struct cpuacct {
+       struct cgroup_subsys_state css;
+       /* cpuusage holds pointer to a u64-type object on every cpu */
+       u64 *cpuusage;
+};
+
+struct cgroup_subsys cpuacct_subsys;
+
+/* return cpu accounting group corresponding to this container */
+static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
+{
+       return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
+                           struct cpuacct, css);
+}
+
+/* return cpu accounting group to which this task belongs */
+static inline struct cpuacct *task_ca(struct task_struct *tsk)
+{
+       return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
+                           struct cpuacct, css);
+}
+
+/* create a new cpu accounting group */
+static struct cgroup_subsys_state *cpuacct_create(
+       struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+       struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+
+       if (!ca)
+               return ERR_PTR(-ENOMEM);
+
+       ca->cpuusage = alloc_percpu(u64);
+       if (!ca->cpuusage) {
+               kfree(ca);
+               return ERR_PTR(-ENOMEM);
+       }
+
+       return &ca->css;
+}
+
+/* destroy an existing cpu accounting group */
+static void
+cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+       struct cpuacct *ca = cgroup_ca(cgrp);
+
+       free_percpu(ca->cpuusage);
+       kfree(ca);
+}
+
+/* return total cpu usage (in nanoseconds) of a group */
+static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       struct cpuacct *ca = cgroup_ca(cgrp);
+       u64 totalcpuusage = 0;
+       int i;
+
+       for_each_possible_cpu(i) {
+               u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
+
+               /*
+                * Take rq->lock to make 64-bit addition safe on 32-bit
+                * platforms.
+                */
+               spin_lock_irq(&cpu_rq(i)->lock);
+               totalcpuusage += *cpuusage;
+               spin_unlock_irq(&cpu_rq(i)->lock);
+       }
+
+       return totalcpuusage;
+}
+
+static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
+                                                               u64 reset)
+{
+       struct cpuacct *ca = cgroup_ca(cgrp);
+       int err = 0;
+       int i;
+
+       if (reset) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       for_each_possible_cpu(i) {
+               u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
+
+               spin_lock_irq(&cpu_rq(i)->lock);
+               *cpuusage = 0;
+               spin_unlock_irq(&cpu_rq(i)->lock);
+       }
+out:
+       return err;
+}
+
+static struct cftype files[] = {
+       {
+               .name = "usage",
+               .read_u64 = cpuusage_read,
+               .write_u64 = cpuusage_write,
+       },
+};
+
+static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+       return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
+}
+
+/*
+ * charge this task's execution time to its accounting group.
+ *
+ * called with rq->lock held.
+ */
+static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
+{
+       struct cpuacct *ca;
+
+       if (!cpuacct_subsys.active)
+               return;
+
+       ca = task_ca(tsk);
+       if (ca) {
+               u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk));
+
+               *cpuusage += cputime;
+       }
+}
+
+struct cgroup_subsys cpuacct_subsys = {
+       .name = "cpuacct",
+       .create = cpuacct_create,
+       .destroy = cpuacct_destroy,
+       .populate = cpuacct_populate,
+       .subsys_id = cpuacct_subsys_id,
+};
+#endif /* CONFIG_CGROUP_CPUACCT */
diff -Nurb linux-2.6.27-590/kernel/sched.c.rej linux-2.6.27-591/kernel/sched.c.rej
--- linux-2.6.27-590/kernel/sched.c.rej 1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.27-591/kernel/sched.c.rej 2010-02-01 19:43:07.000000000 -0500
@@ -0,0 +1,258 @@
+***************
+*** 23,28 ****
+  #include <linux/nmi.h>
+  #include <linux/init.h>
+  #include <asm/uaccess.h>
+  #include <linux/highmem.h>
+  #include <linux/smp_lock.h>
+  #include <asm/mmu_context.h>
+--- 23,29 ----
+  #include <linux/nmi.h>
+  #include <linux/init.h>
+  #include <asm/uaccess.h>
++ #include <linux/arrays.h>
+  #include <linux/highmem.h>
+  #include <linux/smp_lock.h>
+  #include <asm/mmu_context.h>
+***************
+*** 451,456 ****
+  
+  repeat_lock_task:
+       rq = task_rq(p);
+       spin_lock(&rq->lock);
+       if (unlikely(rq != task_rq(p))) {
+               spin_unlock(&rq->lock);
+--- 455,461 ----
+  
+  repeat_lock_task:
+       rq = task_rq(p);
++ 
+       spin_lock(&rq->lock);
+       if (unlikely(rq != task_rq(p))) {
+               spin_unlock(&rq->lock);
+***************
+*** 1761,1766 ****
+        * event cannot wake it up and insert it on the runqueue either.
+        */
+       p->state = TASK_RUNNING;
+  
+       /*
+        * Make sure we do not leak PI boosting priority to the child:
+--- 1766,1786 ----
+        * event cannot wake it up and insert it on the runqueue either.
+        */
+       p->state = TASK_RUNNING;
++ #ifdef CONFIG_CHOPSTIX
++     /* The jiffy of last interruption */
++     if (p->state & TASK_UNINTERRUPTIBLE) {
++                              p->last_interrupted=jiffies;
++      }
++     else
++     if (p->state & TASK_INTERRUPTIBLE) {
++                              p->last_interrupted=INTERRUPTIBLE;
++      }
++     else
++          p->last_interrupted=RUNNING;
++ 
++     /* The jiffy of last execution */ 
++      p->last_ran_j=jiffies;
++ #endif
+  
+       /*
+        * Make sure we do not leak PI boosting priority to the child:
+***************
+*** 3628,3633 ****
+  
+  #endif
+  
+  static inline int interactive_sleep(enum sleep_type sleep_type)
+  {
+       return (sleep_type == SLEEP_INTERACTIVE ||
+--- 3648,3654 ----
+  
+  #endif
+  
++ 
+  static inline int interactive_sleep(enum sleep_type sleep_type)
+  {
+       return (sleep_type == SLEEP_INTERACTIVE ||
+***************
+*** 3637,3652 ****
+  /*
+   * schedule() is the main scheduler function.
+   */
+  asmlinkage void __sched schedule(void)
+  {
+       struct task_struct *prev, *next;
+       struct prio_array *array;
+       struct list_head *queue;
+       unsigned long long now;
+-      unsigned long run_time;
+       int cpu, idx, new_prio;
+       long *switch_count;
+       struct rq *rq;
+  
+       /*
+        * Test if we are atomic.  Since do_exit() needs to call into
+--- 3658,3685 ----
+  /*
+   * schedule() is the main scheduler function.
+   */
++ 
++ #ifdef CONFIG_CHOPSTIX
++ extern void (*rec_event)(void *,unsigned int);
++ struct event_spec {
++      unsigned long pc;
++      unsigned long dcookie;
++      unsigned int count;
++      unsigned int reason;
++ };
++ #endif
++ 
+  asmlinkage void __sched schedule(void)
+  {
+       struct task_struct *prev, *next;
+       struct prio_array *array;
+       struct list_head *queue;
+       unsigned long long now;
++      unsigned long run_time, diff;
+       int cpu, idx, new_prio;
+       long *switch_count;
+       struct rq *rq;
++      int sampling_reason;
+  
+       /*
+        * Test if we are atomic.  Since do_exit() needs to call into
+***************
+*** 3700,3705 ****
+       switch_count = &prev->nivcsw;
+       if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+               switch_count = &prev->nvcsw;
+               if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
+                               unlikely(signal_pending(prev))))
+                       prev->state = TASK_RUNNING;
+--- 3733,3739 ----
+       switch_count = &prev->nivcsw;
+       if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+               switch_count = &prev->nvcsw;
++ 
+               if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
+                               unlikely(signal_pending(prev))))
+                       prev->state = TASK_RUNNING;
+***************
+*** 3709,3714 ****
+                               vx_uninterruptible_inc(prev);
+                       }
+                       deactivate_task(prev, rq);
+               }
+       }
+  
+--- 3743,3759 ----
+                               vx_uninterruptible_inc(prev);
+                       }
+                       deactivate_task(prev, rq);
++ #ifdef CONFIG_CHOPSTIX
++             /* An uninterruptible process just yielded. Record the current jiffie */
++                      if (prev->state & TASK_UNINTERRUPTIBLE) {
++                              prev->last_interrupted=jiffies;
++                      }
++             /* An interruptible process just yielded, or it got preempted. 
++              * Mark it as interruptible */
++                      else if (prev->state & TASK_INTERRUPTIBLE) {
++                              prev->last_interrupted=INTERRUPTIBLE;
++                      }
++ #endif
+               }
+       }
+  
+***************
+*** 3785,3790 ****
+               prev->sleep_avg = 0;
+       prev->timestamp = prev->last_ran = now;
+  
+       sched_info_switch(prev, next);
+       if (likely(prev != next)) {
+               next->timestamp = next->last_ran = now;
+--- 3830,3869 ----
+               prev->sleep_avg = 0;
+       prev->timestamp = prev->last_ran = now;
+  
++ #ifdef CONFIG_CHOPSTIX
++      /* Run only if the Chopstix module so decrees it */
++      if (rec_event) {
++              prev->last_ran_j = jiffies;
++              if (next->last_interrupted!=INTERRUPTIBLE) {
++                      if (next->last_interrupted!=RUNNING) {
++                              diff = (jiffies-next->last_interrupted);
++                              sampling_reason = 0;/* BLOCKING */
++                      }
++                      else {
++                              diff = jiffies-next->last_ran_j; 
++                              sampling_reason = 1;/* PREEMPTION */
++                      }
++ 
++                      if (diff >= HZ/10) {
++                              struct event event;
++                              struct event_spec espec;
++                 struct pt_regs *regs;
++                 regs = task_pt_regs(current);
++ 
++                              espec.reason = sampling_reason;
++                              event.event_data=&espec;
++                              event.task=next;
++                              espec.pc=regs->eip;
++                              event.event_type=2; 
++                              /* index in the event array currently set up */
++                              /* make sure the counters are loaded in the order we want them to show up*/ 
++                              (*rec_event)(&event, diff);
++                      }
++              }
++         /* next has been elected to run */
++              next->last_interrupted=0;
++      }
++ #endif
+       sched_info_switch(prev, next);
+       if (likely(prev != next)) {
+               next->timestamp = next->last_ran = now;
+***************
+*** 5737,5742 ****
+       jiffies_to_timespec(p->policy == SCHED_FIFO ?
+                               0 : task_timeslice(p), &t);
+       read_unlock(&tasklist_lock);
+       retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
+  out_nounlock:
+       return retval;
+--- 5817,5823 ----
+       jiffies_to_timespec(p->policy == SCHED_FIFO ?
+                               0 : task_timeslice(p), &t);
+       read_unlock(&tasklist_lock);
++ 
+       retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
+  out_nounlock:
+       return retval;
+***************
+*** 7980,7982 ****
+  }
+  
+  #endif
+--- 8061,8080 ----
+  }
+  
+  #endif
++ 
++ #ifdef CONFIG_CHOPSTIX
++ void (*rec_event)(void *,unsigned int) = NULL;
++ 
++ /* To support safe calling from asm */
++ asmlinkage void rec_event_asm (struct event *event_signature_in, unsigned int count) {
++     struct pt_regs *regs;
++     struct event_spec *es = event_signature_in->event_data;
++     regs = task_pt_regs(current);
++      event_signature_in->task=current;
++      es->pc=regs->eip;
++     event_signature_in->count=1;
++     (*rec_event)(event_signature_in, count);
++ }
++ EXPORT_SYMBOL(rec_event);
++ EXPORT_SYMBOL(in_sched_functions);
++ #endif
diff -Nurb linux-2.6.27-590/mm/memory.c linux-2.6.27-591/mm/memory.c
--- linux-2.6.27-590/mm/memory.c        2010-02-01 19:42:07.000000000 -0500
+++ linux-2.6.27-591/mm/memory.c        2010-02-01 19:43:07.000000000 -0500
@@ -61,6 +61,7 @@
 
 #include <linux/swapops.h>
 #include <linux/elf.h>
+#include <linux/arrays.h>
 
 #include "internal.h"
 
@@ -2690,6 +2691,15 @@
        return ret;
 }
 
+extern void (*rec_event)(void *,unsigned int);
+struct event_spec {
+       unsigned long pc;
+       unsigned long dcookie; 
+       unsigned count;
+       unsigned char reason;
+};
+
+
 /*
  * By the time we get here, we already hold the mm semaphore
  */
@@ -2719,6 +2729,24 @@
        if (!pte)
                return VM_FAULT_OOM;
 
+#ifdef CONFIG_CHOPSTIX
+       if (rec_event) {
+               struct event event;
+               struct event_spec espec;
+        struct pt_regs *regs;
+        unsigned int pc;
+        regs = task_pt_regs(current);
+        pc = regs->ip & (unsigned int) ~4095;
+
+               espec.reason = 0; /* alloc */
+               event.event_data=&espec;
+               event.task = current;
+               espec.pc=pc;
+               event.event_type=5; 
+               (*rec_event)(&event, 1);
+       }
+#endif
+
        return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
 }
 
diff -Nurb linux-2.6.27-590/mm/memory.c.orig linux-2.6.27-591/mm/memory.c.orig
--- linux-2.6.27-590/mm/memory.c.orig   1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.27-591/mm/memory.c.orig   2010-02-01 19:42:07.000000000 -0500
@@ -0,0 +1,3035 @@
+/*
+ *  linux/mm/memory.c
+ *
+ *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ */
+
+/*
+ * demand-loading started 01.12.91 - seems it is high on the list of
+ * things wanted, and it should be easy to implement. - Linus
+ */
+
+/*
+ * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
+ * pages started 02.12.91, seems to work. - Linus.
+ *
+ * Tested sharing by executing about 30 /bin/sh: under the old kernel it
+ * would have taken more than the 6M I have free, but it worked well as
+ * far as I could see.
+ *
+ * Also corrected some "invalidate()"s - I wasn't doing enough of them.
+ */
+
+/*
+ * Real VM (paging to/from disk) started 18.12.91. Much more work and
+ * thought has to go into this. Oh, well..
+ * 19.12.91  -  works, somewhat. Sometimes I get faults, don't know why.
+ *             Found it. Everything seems to work now.
+ * 20.12.91  -  Ok, making the swap-device changeable like the root.
+ */
+
+/*
+ * 05.04.94  -  Multi-page memory management added for v1.1.
+ *             Idea by Alex Bligh (alex@cconcepts.co.uk)
+ *
+ * 16.07.99  -  Support of BIGMEM added by Gerhard Wichert, Siemens AG
+ *             (Gerhard.Wichert@pdb.siemens.de)
+ *
+ * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/mman.h>
+#include <linux/swap.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/rmap.h>
+#include <linux/module.h>
+#include <linux/delayacct.h>
+#include <linux/init.h>
+#include <linux/writeback.h>
+#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
+
+#include <asm/pgalloc.h>
+#include <asm/uaccess.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/pgtable.h>
+
+#include <linux/swapops.h>
+#include <linux/elf.h>
+
+#include "internal.h"
+
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+/* use the per-pgdat data instead for discontigmem - mbligh */
+unsigned long max_mapnr;
+struct page *mem_map;
+
+EXPORT_SYMBOL(max_mapnr);
+EXPORT_SYMBOL(mem_map);
+#endif
+
+unsigned long num_physpages;
+/*
+ * A number of key systems in x86 including ioremap() rely on the assumption
+ * that high_memory defines the upper bound on direct map memory, then end
+ * of ZONE_NORMAL.  Under CONFIG_DISCONTIG this means that max_low_pfn and
+ * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
+ * and ZONE_HIGHMEM.
+ */
+void * high_memory;
+
+EXPORT_SYMBOL(num_physpages);
+EXPORT_SYMBOL(high_memory);
+
+/*
+ * Randomize the address space (stacks, mmaps, brk, etc.).
+ *
+ * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
+ *   as ancient (libc5 based) binaries can segfault. )
+ */
+int randomize_va_space __read_mostly =
+#ifdef CONFIG_COMPAT_BRK
+                                       1;
+#else
+                                       2;
+#endif
+
+static int __init disable_randmaps(char *s)
+{
+       randomize_va_space = 0;
+       return 1;
+}
+__setup("norandmaps", disable_randmaps);
+
+
+/*
+ * If a p?d_bad entry is found while walking page tables, report
+ * the error, before resetting entry to p?d_none.  Usually (but
+ * very seldom) called out from the p?d_none_or_clear_bad macros.
+ */
+
+void pgd_clear_bad(pgd_t *pgd)
+{
+       pgd_ERROR(*pgd);
+       pgd_clear(pgd);
+}
+
+void pud_clear_bad(pud_t *pud)
+{
+       pud_ERROR(*pud);
+       pud_clear(pud);
+}
+
+void pmd_clear_bad(pmd_t *pmd)
+{
+       pmd_ERROR(*pmd);
+       pmd_clear(pmd);
+}
+
+/*
+ * Note: this doesn't free the actual pages themselves. That
+ * has been handled earlier when unmapping all the memory regions.
+ */
+static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
+{
+       pgtable_t token = pmd_pgtable(*pmd);
+       pmd_clear(pmd);
+       pte_free_tlb(tlb, token);
+       tlb->mm->nr_ptes--;
+}
+
+static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
+                               unsigned long addr, unsigned long end,
+                               unsigned long floor, unsigned long ceiling)
+{
+       pmd_t *pmd;
+       unsigned long next;
+       unsigned long start;
+
+       start = addr;
+       pmd = pmd_offset(pud, addr);
+       do {
+               next = pmd_addr_end(addr, end);
+               if (pmd_none_or_clear_bad(pmd))
+                       continue;
+               free_pte_range(tlb, pmd);
+       } while (pmd++, addr = next, addr != end);
+
+       start &= PUD_MASK;
+       if (start < floor)
+               return;
+       if (ceiling) {
+               ceiling &= PUD_MASK;
+               if (!ceiling)
+                       return;
+       }
+       if (end - 1 > ceiling - 1)
+               return;
+
+       pmd = pmd_offset(pud, start);
+       pud_clear(pud);
+       pmd_free_tlb(tlb, pmd);
+}
+
+static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
+                               unsigned long addr, unsigned long end,
+                               unsigned long floor, unsigned long ceiling)
+{
+       pud_t *pud;
+       unsigned long next;
+       unsigned long start;
+
+       start = addr;
+       pud = pud_offset(pgd, addr);
+       do {
+               next = pud_addr_end(addr, end);
+               if (pud_none_or_clear_bad(pud))
+                       continue;
+               free_pmd_range(tlb, pud, addr, next, floor, ceiling);
+       } while (pud++, addr = next, addr != end);
+
+       start &= PGDIR_MASK;
+       if (start < floor)
+               return;
+       if (ceiling) {
+               ceiling &= PGDIR_MASK;
+               if (!ceiling)
+                       return;
+       }
+       if (end - 1 > ceiling - 1)
+               return;
+
+       pud = pud_offset(pgd, start);
+       pgd_clear(pgd);
+       pud_free_tlb(tlb, pud);
+}
+
+/*
+ * This function frees user-level page tables of a process.
+ *
+ * Must be called with pagetable lock held.
+ */
+void free_pgd_range(struct mmu_gather *tlb,
+                       unsigned long addr, unsigned long end,
+                       unsigned long floor, unsigned long ceiling)
+{
+       pgd_t *pgd;
+       unsigned long next;
+       unsigned long start;
+
+       /*
+        * The next few lines have given us lots of grief...
+        *
+        * Why are we testing PMD* at this top level?  Because often
+        * there will be no work to do at all, and we'd prefer not to
+        * go all the way down to the bottom just to discover that.
+        *
+        * Why all these "- 1"s?  Because 0 represents both the bottom
+        * of the address space and the top of it (using -1 for the
+        * top wouldn't help much: the masks would do the wrong thing).
+        * The rule is that addr 0 and floor 0 refer to the bottom of
+        * the address space, but end 0 and ceiling 0 refer to the top
+        * Comparisons need to use "end - 1" and "ceiling - 1" (though
+        * that end 0 case should be mythical).
+        *
+        * Wherever addr is brought up or ceiling brought down, we must
+        * be careful to reject "the opposite 0" before it confuses the
+        * subsequent tests.  But what about where end is brought down
+        * by PMD_SIZE below? no, end can't go down to 0 there.
+        *
+        * Whereas we round start (addr) and ceiling down, by different
+        * masks at different levels, in order to test whether a table
+        * now has no other vmas using it, so can be freed, we don't
+        * bother to round floor or end up - the tests don't need that.
+        */
+
+       addr &= PMD_MASK;
+       if (addr < floor) {
+               addr += PMD_SIZE;
+               if (!addr)
+                       return;
+       }
+       if (ceiling) {
+               ceiling &= PMD_MASK;
+               if (!ceiling)
+                       return;
+       }
+       if (end - 1 > ceiling - 1)
+               end -= PMD_SIZE;
+       if (addr > end - 1)
+               return;
+
+       start = addr;
+       pgd = pgd_offset(tlb->mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               if (pgd_none_or_clear_bad(pgd))
+                       continue;
+               free_pud_range(tlb, pgd, addr, next, floor, ceiling);
+       } while (pgd++, addr = next, addr != end);
+}
+
+void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
+               unsigned long floor, unsigned long ceiling)
+{
+       while (vma) {
+               struct vm_area_struct *next = vma->vm_next;
+               unsigned long addr = vma->vm_start;
+
+               /*
+                * Hide vma from rmap and vmtruncate before freeing pgtables
+                */
+               anon_vma_unlink(vma);
+               unlink_file_vma(vma);
+
+               if (is_vm_hugetlb_page(vma)) {
+                       hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
+                               floor, next? next->vm_start: ceiling);
+               } else {
+                       /*
+                        * Optimization: gather nearby vmas into one call down
+                        */
+                       while (next && next->vm_start <= vma->vm_end + PMD_SIZE
+                              && !is_vm_hugetlb_page(next)) {
+                               vma = next;
+                               next = vma->vm_next;
+                               anon_vma_unlink(vma);
+                               unlink_file_vma(vma);
+                       }
+                       free_pgd_range(tlb, addr, vma->vm_end,
+                               floor, next? next->vm_start: ceiling);
+               }
+               vma = next;
+       }
+}
+
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+{
+       pgtable_t new = pte_alloc_one(mm, address);
+       if (!new)
+               return -ENOMEM;
+
+       /*
+        * Ensure all pte setup (eg. pte page lock and page clearing) are
+        * visible before the pte is made visible to other CPUs by being
+        * put into page tables.
+        *
+        * The other side of the story is the pointer chasing in the page
+        * table walking code (when walking the page table without locking;
+        * ie. most of the time). Fortunately, these data accesses consist
+        * of a chain of data-dependent loads, meaning most CPUs (alpha
+        * being the notable exception) will already guarantee loads are
+        * seen in-order. See the alpha page table accessors for the
+        * smp_read_barrier_depends() barriers in page table walking code.
+        */
+       smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
+
+       spin_lock(&mm->page_table_lock);
+       if (!pmd_present(*pmd)) {       /* Has another populated it ? */
+               mm->nr_ptes++;
+               pmd_populate(mm, pmd, new);
+               new = NULL;
+       }
+       spin_unlock(&mm->page_table_lock);
+       if (new)
+               pte_free(mm, new);
+       return 0;
+}
+
+int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
+{
+       pte_t *new = pte_alloc_one_kernel(&init_mm, address);
+       if (!new)
+               return -ENOMEM;
+
+       smp_wmb(); /* See comment in __pte_alloc */
+
+       spin_lock(&init_mm.page_table_lock);
+       if (!pmd_present(*pmd)) {       /* Has another populated it ? */
+               pmd_populate_kernel(&init_mm, pmd, new);
+               new = NULL;
+       }
+       spin_unlock(&init_mm.page_table_lock);
+       if (new)
+               pte_free_kernel(&init_mm, new);
+       return 0;
+}
+
+static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
+{
+       if (file_rss)
+               add_mm_counter(mm, file_rss, file_rss);
+       if (anon_rss)
+               add_mm_counter(mm, anon_rss, anon_rss);
+}
+
+/*
+ * This function is called to print an error when a bad pte
+ * is found. For example, we might have a PFN-mapped pte in
+ * a region that doesn't allow it.
+ *
+ * The calling function must still handle the error.
+ */
+static void print_bad_pte(struct vm_area_struct *vma, pte_t pte,
+                         unsigned long vaddr)
+{
+       printk(KERN_ERR "Bad pte = %08llx, process = %s, "
+                       "vm_flags = %lx, vaddr = %lx\n",
+               (long long)pte_val(pte),
+               (vma->vm_mm == current->mm ? current->comm : "???"),
+               vma->vm_flags, vaddr);
+       dump_stack();
+}
+
+static inline int is_cow_mapping(unsigned int flags)
+{
+       return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+}
+
+/*
+ * vm_normal_page -- This function gets the "struct page" associated with a pte.
+ *
+ * "Special" mappings do not wish to be associated with a "struct page" (either
+ * it doesn't exist, or it exists but they don't want to touch it). In this
+ * case, NULL is returned here. "Normal" mappings do have a struct page.
+ *
+ * There are 2 broad cases. Firstly, an architecture may define a pte_special()
+ * pte bit, in which case this function is trivial. Secondly, an architecture
+ * may not have a spare pte bit, which requires a more complicated scheme,
+ * described below.
+ *
+ * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
+ * special mapping (even if there are underlying and valid "struct pages").
+ * COWed pages of a VM_PFNMAP are always normal.
+ *
+ * The way we recognize COWed pages within VM_PFNMAP mappings is through the
+ * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
+ * set, and the vm_pgoff will point to the first PFN mapped: thus every special
+ * mapping will always honor the rule
+ *
+ *     pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
+ *
+ * And for normal mappings this is false.
+ *
+ * This restricts such mappings to be a linear translation from virtual address
+ * to pfn. To get around this restriction, we allow arbitrary mappings so long
+ * as the vma is not a COW mapping; in that case, we know that all ptes are
+ * special (because none can have been COWed).
+ *
+ *
+ * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
+ *
+ * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
+ * page" backing, however the difference is that _all_ pages with a struct
+ * page (that is, those where pfn_valid is true) are refcounted and considered
+ * normal pages by the VM. The disadvantage is that pages are refcounted
+ * (which can be slower and simply not an option for some PFNMAP users). The
+ * advantage is that we don't have to follow the strict linearity rule of
+ * PFNMAP mappings in order to support COWable mappings.
+ *
+ */
+#ifdef __HAVE_ARCH_PTE_SPECIAL
+# define HAVE_PTE_SPECIAL 1
+#else
+# define HAVE_PTE_SPECIAL 0
+#endif
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+                               pte_t pte)
+{
+       unsigned long pfn;
+
+       if (HAVE_PTE_SPECIAL) {
+               if (likely(!pte_special(pte))) {
+                       VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+                       return pte_page(pte);
+               }
+               VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
+               return NULL;
+       }
+
+       /* !HAVE_PTE_SPECIAL case follows: */
+
+       pfn = pte_pfn(pte);
+
+       if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
+               if (vma->vm_flags & VM_MIXEDMAP) {
+                       if (!pfn_valid(pfn))
+                               return NULL;
+                       goto out;
+               } else {
+                       unsigned long off;
+                       off = (addr - vma->vm_start) >> PAGE_SHIFT;
+                       if (pfn == vma->vm_pgoff + off)
+                               return NULL;
+                       if (!is_cow_mapping(vma->vm_flags))
+                               return NULL;
+               }
+       }
+
+       VM_BUG_ON(!pfn_valid(pfn));
+
+       /*
+        * NOTE! We still have PageReserved() pages in the page tables.
+        *
+        * eg. VDSO mappings can cause them to exist.
+        */
+out:
+       return pfn_to_page(pfn);
+}
+
+/*
+ * copy one vm_area from one task to the other. Assumes the page tables
+ * already present in the new task to be cleared in the whole range
+ * covered by this vma.
+ */
+
+static inline void
+copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+               pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
+               unsigned long addr, int *rss)
+{
+       unsigned long vm_flags = vma->vm_flags;
+       pte_t pte = *src_pte;
+       struct page *page;
+
+       /* pte contains position in swap or file, so copy. */
+       if (unlikely(!pte_present(pte))) {
+               if (!pte_file(pte)) {
+                       swp_entry_t entry = pte_to_swp_entry(pte);
+
+                       swap_duplicate(entry);
+                       /* make sure dst_mm is on swapoff's mmlist. */
+                       if (unlikely(list_empty(&dst_mm->mmlist))) {
+                               spin_lock(&mmlist_lock);
+                               if (list_empty(&dst_mm->mmlist))
+                                       list_add(&dst_mm->mmlist,
+                                                &src_mm->mmlist);
+                               spin_unlock(&mmlist_lock);
+                       }
+                       if (is_write_migration_entry(entry) &&
+                                       is_cow_mapping(vm_flags)) {
+                               /*
+                                * COW mappings require pages in both parent
+                                * and child to be set to read.
+                                */
+                               make_migration_entry_read(&entry);
+                               pte = swp_entry_to_pte(entry);
+                               set_pte_at(src_mm, addr, src_pte, pte);
+                       }
+               }
+               goto out_set_pte;
+       }
+
+       /*
+        * If it's a COW mapping, write protect it both
+        * in the parent and the child
+        */
+       if (is_cow_mapping(vm_flags)) {
+               ptep_set_wrprotect(src_mm, addr, src_pte);
+               pte = pte_wrprotect(pte);
+       }
+
+       /*
+        * If it's a shared mapping, mark it clean in
+        * the child
+        */
+       if (vm_flags & VM_SHARED)
+               pte = pte_mkclean(pte);
+       pte = pte_mkold(pte);
+
+       page = vm_normal_page(vma, addr, pte);
+       if (page) {
+               get_page(page);
+               page_dup_rmap(page, vma, addr);
+               rss[!!PageAnon(page)]++;
+       }
+
+out_set_pte:
+       set_pte_at(dst_mm, addr, dst_pte, pte);
+}
+
+static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+               pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
+               unsigned long addr, unsigned long end)
+{
+       pte_t *src_pte, *dst_pte;
+       spinlock_t *src_ptl, *dst_ptl;
+       int progress = 0;
+       int rss[2];
+
+       if (!vx_rss_avail(dst_mm, ((end - addr)/PAGE_SIZE + 1)))
+               return -ENOMEM;
+
+again:
+       rss[1] = rss[0] = 0;
+       dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
+       if (!dst_pte)
+               return -ENOMEM;
+       src_pte = pte_offset_map_nested(src_pmd, addr);
+       src_ptl = pte_lockptr(src_mm, src_pmd);
+       spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
+       arch_enter_lazy_mmu_mode();
+
+       do {
+               /*
+                * We are holding two locks at this point - either of them
+                * could generate latencies in another task on another CPU.
+                */
+               if (progress >= 32) {
+                       progress = 0;
+                       if (need_resched() ||
+                           spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
+                               break;
+               }
+               if (pte_none(*src_pte)) {
+                       progress++;
+                       continue;
+               }
+               copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
+               progress += 8;
+       } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
+
+       arch_leave_lazy_mmu_mode();
+       spin_unlock(src_ptl);
+       pte_unmap_nested(src_pte - 1);
+       add_mm_rss(dst_mm, rss[0], rss[1]);
+       pte_unmap_unlock(dst_pte - 1, dst_ptl);
+       cond_resched();
+       if (addr != end)
+               goto again;
+       return 0;
+}
+
+static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+               pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
+               unsigned long addr, unsigned long end)
+{
+       pmd_t *src_pmd, *dst_pmd;
+       unsigned long next;
+
+       dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
+       if (!dst_pmd)
+               return -ENOMEM;
+       src_pmd = pmd_offset(src_pud, addr);
+       do {
+               next = pmd_addr_end(addr, end);
+               if (pmd_none_or_clear_bad(src_pmd))
+                       continue;
+               if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
+                                               vma, addr, next))
+                       return -ENOMEM;
+       } while (dst_pmd++, src_pmd++, addr = next, addr != end);
+       return 0;
+}
+
+static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+               pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
+               unsigned long addr, unsigned long end)
+{
+       pud_t *src_pud, *dst_pud;
+       unsigned long next;
+
+       dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
+       if (!dst_pud)
+               return -ENOMEM;
+       src_pud = pud_offset(src_pgd, addr);
+       do {
+               next = pud_addr_end(addr, end);
+               if (pud_none_or_clear_bad(src_pud))
+                       continue;
+               if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
+                                               vma, addr, next))
+                       return -ENOMEM;
+       } while (dst_pud++, src_pud++, addr = next, addr != end);
+       return 0;
+}
+
+int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+               struct vm_area_struct *vma)
+{
+       pgd_t *src_pgd, *dst_pgd;
+       unsigned long next;
+       unsigned long addr = vma->vm_start;
+       unsigned long end = vma->vm_end;
+       int ret;
+
+       /*
+        * Don't copy ptes where a page fault will fill them correctly.
+        * Fork becomes much lighter when there are big shared or private
+        * readonly mappings. The tradeoff is that copy_page_range is more
+        * efficient than faulting.
+        */
+       if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
+               if (!vma->anon_vma)
+                       return 0;
+       }
+
+       if (is_vm_hugetlb_page(vma))
+               return copy_hugetlb_page_range(dst_mm, src_mm, vma);
+
+       /*
+        * We need to invalidate the secondary MMU mappings only when
+        * there could be a permission downgrade on the ptes of the
+        * parent mm. And a permission downgrade will only happen if
+        * is_cow_mapping() returns true.
+        */
+       if (is_cow_mapping(vma->vm_flags))
+               mmu_notifier_invalidate_range_start(src_mm, addr, end);
+
+       ret = 0;
+       dst_pgd = pgd_offset(dst_mm, addr);
+       src_pgd = pgd_offset(src_mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               if (pgd_none_or_clear_bad(src_pgd))
+                       continue;
+               if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
+                                           vma, addr, next))) {
+                       ret = -ENOMEM;
+                       break;
+               }
+       } while (dst_pgd++, src_pgd++, addr = next, addr != end);
+
+       if (is_cow_mapping(vma->vm_flags))
+               mmu_notifier_invalidate_range_end(src_mm,
+                                                 vma->vm_start, end);
+       return ret;
+}
+
+static unsigned long zap_pte_range(struct mmu_gather *tlb,
+                               struct vm_area_struct *vma, pmd_t *pmd,
+                               unsigned long addr, unsigned long end,
+                               long *zap_work, struct zap_details *details)
+{
+       struct mm_struct *mm = tlb->mm;
+       pte_t *pte;
+       spinlock_t *ptl;
+       int file_rss = 0;
+       int anon_rss = 0;
+
+       pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+       arch_enter_lazy_mmu_mode();
+       do {
+               pte_t ptent = *pte;
+               if (pte_none(ptent)) {
+                       (*zap_work)--;
+                       continue;
+               }
+
+               (*zap_work) -= PAGE_SIZE;
+
+               if (pte_present(ptent)) {
+                       struct page *page;
+
+                       page = vm_normal_page(vma, addr, ptent);
+                       if (unlikely(details) && page) {
+                               /*
+                                * unmap_shared_mapping_pages() wants to
+                                * invalidate cache without truncating:
+                                * unmap shared but keep private pages.
+                                */
+                               if (details->check_mapping &&
+                                   details->check_mapping != page->mapping)
+                                       continue;
+                               /*
+                                * Each page->index must be checked when
+                                * invalidating or truncating nonlinear.
+                                */
+                               if (details->nonlinear_vma &&
+                                   (page->index < details->first_index ||
+                                    page->index > details->last_index))
+                                       continue;
+                       }
+                       ptent = ptep_get_and_clear_full(mm, addr, pte,
+                                                       tlb->fullmm);
+                       tlb_remove_tlb_entry(tlb, pte, addr);
+                       if (unlikely(!page))
+                               continue;
+                       if (unlikely(details) && details->nonlinear_vma
+                           && linear_page_index(details->nonlinear_vma,
+                                               addr) != page->index)
+                               set_pte_at(mm, addr, pte,
+                                          pgoff_to_pte(page->index));
+                       if (PageAnon(page))
+                               anon_rss--;
+                       else {
+                               if (pte_dirty(ptent))
+                                       set_page_dirty(page);
+                               if (pte_young(ptent))
+                                       SetPageReferenced(page);
+                               file_rss--;
+                       }
+                       page_remove_rmap(page, vma);
+                       tlb_remove_page(tlb, page);
+                       continue;
+               }
+               /*
+                * If details->check_mapping, we leave swap entries;
+                * if details->nonlinear_vma, we leave file entries.
+                */
+               if (unlikely(details))
+                       continue;
+               if (!pte_file(ptent))
+                       free_swap_and_cache(pte_to_swp_entry(ptent));
+               pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
+       } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
+
+       add_mm_rss(mm, file_rss, anon_rss);
+       arch_leave_lazy_mmu_mode();
+       pte_unmap_unlock(pte - 1, ptl);
+
+       return addr;
+}
+
+static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
+                               struct vm_area_struct *vma, pud_t *pud,
+                               unsigned long addr, unsigned long end,
+                               long *zap_work, struct zap_details *details)
+{
+       pmd_t *pmd;
+       unsigned long next;
+
+       pmd = pmd_offset(pud, addr);
+       do {
+               next = pmd_addr_end(addr, end);
+               if (pmd_none_or_clear_bad(pmd)) {
+                       (*zap_work)--;
+                       continue;
+               }
+               next = zap_pte_range(tlb, vma, pmd, addr, next,
+                                               zap_work, details);
+       } while (pmd++, addr = next, (addr != end && *zap_work > 0));
+
+       return addr;
+}
+
+static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
+                               struct vm_area_struct *vma, pgd_t *pgd,
+                               unsigned long addr, unsigned long end,
+                               long *zap_work, struct zap_details *details)
+{
+       pud_t *pud;
+       unsigned long next;
+
+       pud = pud_offset(pgd, addr);
+       do {
+               next = pud_addr_end(addr, end);
+               if (pud_none_or_clear_bad(pud)) {
+                       (*zap_work)--;
+                       continue;
+               }
+               next = zap_pmd_range(tlb, vma, pud, addr, next,
+                                               zap_work, details);
+       } while (pud++, addr = next, (addr != end && *zap_work > 0));
+
+       return addr;
+}
+
+static unsigned long unmap_page_range(struct mmu_gather *tlb,
+                               struct vm_area_struct *vma,
+                               unsigned long addr, unsigned long end,
+                               long *zap_work, struct zap_details *details)
+{
+       pgd_t *pgd;
+       unsigned long next;
+
+       if (details && !details->check_mapping && !details->nonlinear_vma)
+               details = NULL;
+
+       BUG_ON(addr >= end);
+       tlb_start_vma(tlb, vma);
+       pgd = pgd_offset(vma->vm_mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               if (pgd_none_or_clear_bad(pgd)) {
+                       (*zap_work)--;
+                       continue;
+               }
+               next = zap_pud_range(tlb, vma, pgd, addr, next,
+                                               zap_work, details);
+       } while (pgd++, addr = next, (addr != end && *zap_work > 0));
+       tlb_end_vma(tlb, vma);
+
+       return addr;
+}
+
+#ifdef CONFIG_PREEMPT
+# define ZAP_BLOCK_SIZE        (8 * PAGE_SIZE)
+#else
+/* No preempt: go for improved straight-line efficiency */
+# define ZAP_BLOCK_SIZE        (1024 * PAGE_SIZE)
+#endif
+
+/**
+ * unmap_vmas - unmap a range of memory covered by a list of vma's
+ * @tlbp: address of the caller's struct mmu_gather
+ * @vma: the starting vma
+ * @start_addr: virtual address at which to start unmapping
+ * @end_addr: virtual address at which to end unmapping
+ * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
+ * @details: details of nonlinear truncation or shared cache invalidation
+ *
+ * Returns the end address of the unmapping (restart addr if interrupted).
+ *
+ * Unmap all pages in the vma list.
+ *
+ * We aim to not hold locks for too long (for scheduling latency reasons).
+ * So zap pages in ZAP_BLOCK_SIZE bytecounts.  This means we need to
+ * return the ending mmu_gather to the caller.
+ *
+ * Only addresses between `start' and `end' will be unmapped.
+ *
+ * The VMA list must be sorted in ascending virtual address order.
+ *
+ * unmap_vmas() assumes that the caller will flush the whole unmapped address
+ * range after unmap_vmas() returns.  So the only responsibility here is to
+ * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
+ * drops the lock and schedules.
+ */
+unsigned long unmap_vmas(struct mmu_gather **tlbp,
+               struct vm_area_struct *vma, unsigned long start_addr,
+               unsigned long end_addr, unsigned long *nr_accounted,
+               struct zap_details *details)
+{
+       long zap_work = ZAP_BLOCK_SIZE;
+       unsigned long tlb_start = 0;    /* For tlb_finish_mmu */
+       int tlb_start_valid = 0;
+       unsigned long start = start_addr;
+       spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
+       int fullmm = (*tlbp)->fullmm;
+       struct mm_struct *mm = vma->vm_mm;
+
+       mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
+       for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
+               unsigned long end;
+
+               start = max(vma->vm_start, start_addr);
+               if (start >= vma->vm_end)
+                       continue;
+               end = min(vma->vm_end, end_addr);
+               if (end <= vma->vm_start)
+                       continue;
+
+               if (vma->vm_flags & VM_ACCOUNT)
+                       *nr_accounted += (end - start) >> PAGE_SHIFT;
+
+               while (start != end) {
+                       if (!tlb_start_valid) {
+                               tlb_start = start;
+                               tlb_start_valid = 1;
+                       }
+
+                       if (unlikely(is_vm_hugetlb_page(vma))) {
+                               /*
+                                * It is undesirable to test vma->vm_file as it
+                                * should be non-null for valid hugetlb area.
+                                * However, vm_file will be NULL in the error
+                                * cleanup path of do_mmap_pgoff. When
+                                * hugetlbfs ->mmap method fails,
+                                * do_mmap_pgoff() nullifies vma->vm_file
+                                * before calling this function to clean up.
+                                * Since no pte has actually been setup, it is
+                                * safe to do nothing in this case.
+                                */
+                               if (vma->vm_file) {
+                                       unmap_hugepage_range(vma, start, end, NULL);
+                                       zap_work -= (end - start) /
+                                       pages_per_huge_page(hstate_vma(vma));
+                               }
+
+                               start = end;
+                       } else
+                               start = unmap_page_range(*tlbp, vma,
+                                               start, end, &zap_work, details);
+
+                       if (zap_work > 0) {
+                               BUG_ON(start != end);
+                               break;
+                       }
+
+                       tlb_finish_mmu(*tlbp, tlb_start, start);
+
+                       if (need_resched() ||
+                               (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
+                               if (i_mmap_lock) {
+                                       *tlbp = NULL;
+                                       goto out;
+                               }
+                               cond_resched();
+                       }
+
+                       *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
+                       tlb_start_valid = 0;
+                       zap_work = ZAP_BLOCK_SIZE;
+               }
+       }
+out:
+       mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
+       return start;   /* which is now the end (or restart) address */
+}
+
+/**
+ * zap_page_range - remove user pages in a given range
+ * @vma: vm_area_struct holding the applicable pages
+ * @address: starting address of pages to zap
+ * @size: number of bytes to zap
+ * @details: details of nonlinear truncation or shared cache invalidation
+ */
+unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
+               unsigned long size, struct zap_details *details)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       struct mmu_gather *tlb;
+       unsigned long end = address + size;
+       unsigned long nr_accounted = 0;
+
+       lru_add_drain();
+       tlb = tlb_gather_mmu(mm, 0);
+       update_hiwater_rss(mm);
+       end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
+       if (tlb)
+               tlb_finish_mmu(tlb, address, end);
+       return end;
+}
+
+/**
+ * zap_vma_ptes - remove ptes mapping the vma
+ * @vma: vm_area_struct holding ptes to be zapped
+ * @address: starting address of pages to zap
+ * @size: number of bytes to zap
+ *
+ * This function only unmaps ptes assigned to VM_PFNMAP vmas.
+ *
+ * The entire address range must be fully contained within the vma.
+ *
+ * Returns 0 if successful.
+ */
+int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+               unsigned long size)
+{
+       if (address < vma->vm_start || address + size > vma->vm_end ||
+                       !(vma->vm_flags & VM_PFNMAP))
+               return -1;
+       zap_page_range(vma, address, size, NULL);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(zap_vma_ptes);
+
+/*
+ * Do a quick page-table lookup for a single page.
+ */
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+                       unsigned int flags)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *ptep, pte;
+       spinlock_t *ptl;
+       struct page *page;
+       struct mm_struct *mm = vma->vm_mm;
+
+       page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
+       if (!IS_ERR(page)) {
+               BUG_ON(flags & FOLL_GET);
+               goto out;
+       }
+
+       page = NULL;
+       pgd = pgd_offset(mm, address);
+       if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+               goto no_page_table;
+
+       pud = pud_offset(pgd, address);
+       if (pud_none(*pud))
+               goto no_page_table;
+       if (pud_huge(*pud)) {
+               BUG_ON(flags & FOLL_GET);
+               page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
+               goto out;
+       }
+       if (unlikely(pud_bad(*pud)))
+               goto no_page_table;
+
+       pmd = pmd_offset(pud, address);
+       if (pmd_none(*pmd))
+               goto no_page_table;
+       if (pmd_huge(*pmd)) {
+               BUG_ON(flags & FOLL_GET);
+               page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
+               goto out;
+       }
+       if (unlikely(pmd_bad(*pmd)))
+               goto no_page_table;
+
+       ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+
+       pte = *ptep;
+       if (!pte_present(pte))
+               goto no_page;
+       if ((flags & FOLL_WRITE) && !pte_write(pte))
+               goto unlock;
+       page = vm_normal_page(vma, address, pte);
+       if (unlikely(!page))
+               goto bad_page;
+
+       if (flags & FOLL_GET)
+               get_page(page);
+       if (flags & FOLL_TOUCH) {
+               if ((flags & FOLL_WRITE) &&
+                   !pte_dirty(pte) && !PageDirty(page))
+                       set_page_dirty(page);
+               mark_page_accessed(page);
+       }
+unlock:
+       pte_unmap_unlock(ptep, ptl);
+out:
+       return page;
+
+bad_page:
+       pte_unmap_unlock(ptep, ptl);
+       return ERR_PTR(-EFAULT);
+
+no_page:
+       pte_unmap_unlock(ptep, ptl);
+       if (!pte_none(pte))
+               return page;
+       /* Fall through to ZERO_PAGE handling */
+no_page_table:
+       /*
+        * When core dumping an enormous anonymous area that nobody
+        * has touched so far, we don't want to allocate page tables.
+        */
+       if (flags & FOLL_ANON) {
+               page = ZERO_PAGE(0);
+               if (flags & FOLL_GET)
+                       get_page(page);
+               BUG_ON(flags & FOLL_WRITE);
+       }
+       return page;
+}
+
+/* Can we do the FOLL_ANON optimization? */
+static inline int use_zero_page(struct vm_area_struct *vma)
+{
+       /*
+        * We don't want to optimize FOLL_ANON for make_pages_present()
+        * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
+        * we want to get the page from the page tables to make sure
+        * that we serialize and update with any other user of that
+        * mapping.
+        */
+       if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
+               return 0;
+       /*
+        * And if we have a fault routine, it's not an anonymous region.
+        */
+       return !vma->vm_ops || !vma->vm_ops->fault;
+}
+
+int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+               unsigned long start, int len, int write, int force,
+               struct page **pages, struct vm_area_struct **vmas)
+{
+       int i;
+       unsigned int vm_flags;
+
+       if (len <= 0)
+               return 0;
+       /* 
+        * Require read or write permissions.
+        * If 'force' is set, we only require the "MAY" flags.
+        */
+       vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+       vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+       i = 0;
+
+       do {
+               struct vm_area_struct *vma;
+               unsigned int foll_flags;
+
+               vma = find_extend_vma(mm, start);
+               if (!vma && in_gate_area(tsk, start)) {
+                       unsigned long pg = start & PAGE_MASK;
+                       struct vm_area_struct *gate_vma = get_gate_vma(tsk);
+                       pgd_t *pgd;
+                       pud_t *pud;
+                       pmd_t *pmd;
+                       pte_t *pte;
+                       if (write) /* user gate pages are read-only */
+                               return i ? : -EFAULT;
+                       if (pg > TASK_SIZE)
+                               pgd = pgd_offset_k(pg);
+                       else
+                               pgd = pgd_offset_gate(mm, pg);
+                       BUG_ON(pgd_none(*pgd));
+                       pud = pud_offset(pgd, pg);
+                       BUG_ON(pud_none(*pud));
+                       pmd = pmd_offset(pud, pg);
+                       if (pmd_none(*pmd))
+                               return i ? : -EFAULT;
+                       pte = pte_offset_map(pmd, pg);
+                       if (pte_none(*pte)) {
+                               pte_unmap(pte);
+                               return i ? : -EFAULT;
+                       }
+                       if (pages) {
+                               struct page *page = vm_normal_page(gate_vma, start, *pte);
+                               pages[i] = page;
+                               if (page)
+                                       get_page(page);
+                       }
+                       pte_unmap(pte);
+                       if (vmas)
+                               vmas[i] = gate_vma;
+                       i++;
+                       start += PAGE_SIZE;
+                       len--;
+                       continue;
+               }
+
+               if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
+                               || !(vm_flags & vma->vm_flags))
+                       return i ? : -EFAULT;
+
+               if (is_vm_hugetlb_page(vma)) {
+                       i = follow_hugetlb_page(mm, vma, pages, vmas,
+                                               &start, &len, i, write);
+                       continue;
+               }
+
+               foll_flags = FOLL_TOUCH;
+               if (pages)
+                       foll_flags |= FOLL_GET;
+               if (!write && use_zero_page(vma))
+                       foll_flags |= FOLL_ANON;
+
+               do {
+                       struct page *page;
+
+                       /*
+                        * If tsk is ooming, cut off its access to large memory
+                        * allocations. It has a pending SIGKILL, but it can't
+                        * be processed until returning to user space.
+                        */
+                       if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
+                               return i ? i : -ENOMEM;
+
+                       if (write)
+                               foll_flags |= FOLL_WRITE;
+
+                       cond_resched();
+                       while (!(page = follow_page(vma, start, foll_flags))) {
+                               int ret;
+                               ret = handle_mm_fault(mm, vma, start,
+                                               foll_flags & FOLL_WRITE);
+                               if (ret & VM_FAULT_ERROR) {
+                                       if (ret & VM_FAULT_OOM)
+                                               return i ? i : -ENOMEM;
+                                       else if (ret & VM_FAULT_SIGBUS)
+                                               return i ? i : -EFAULT;
+                                       BUG();
+                               }
+                               if (ret & VM_FAULT_MAJOR)
+                                       tsk->maj_flt++;
+                               else
+                                       tsk->min_flt++;
+
+                               /*
+                                * The VM_FAULT_WRITE bit tells us that
+                                * do_wp_page has broken COW when necessary,
+                                * even if maybe_mkwrite decided not to set
+                                * pte_write. We can thus safely do subsequent
+                                * page lookups as if they were reads.
+                                */
+                               if (ret & VM_FAULT_WRITE)
+                                       foll_flags &= ~FOLL_WRITE;
+
+                               cond_resched();
+                       }
+                       if (IS_ERR(page))
+                               return i ? i : PTR_ERR(page);
+                       if (pages) {
+                               pages[i] = page;
+
+                               flush_anon_page(vma, page, start);
+                               flush_dcache_page(page);
+                       }
+                       if (vmas)
+                               vmas[i] = vma;
+                       i++;
+                       start += PAGE_SIZE;
+                       len--;
+               } while (len && start < vma->vm_end);
+       } while (len);
+       return i;
+}
+EXPORT_SYMBOL(get_user_pages);
+
+pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
+                       spinlock_t **ptl)
+{
+       pgd_t * pgd = pgd_offset(mm, addr);
+       pud_t * pud = pud_alloc(mm, pgd, addr);
+       if (pud) {
+               pmd_t * pmd = pmd_alloc(mm, pud, addr);
+               if (pmd)
+                       return pte_alloc_map_lock(mm, pmd, addr, ptl);
+       }
+       return NULL;
+}
+
+/*
+ * This is the old fallback for page remapping.
+ *
+ * For historical reasons, it only allows reserved pages. Only
+ * old drivers should use this, and they needed to mark their
+ * pages reserved for the old functions anyway.
+ */
+static int insert_page(struct vm_area_struct *vma, unsigned long addr,
+                       struct page *page, pgprot_t prot)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       int retval;
+       pte_t *pte;
+       spinlock_t *ptl;
+
+       retval = mem_cgroup_charge(page, mm, GFP_KERNEL);
+       if (retval)
+               goto out;
+
+       retval = -EINVAL;
+       if (PageAnon(page))
+               goto out_uncharge;
+       retval = -ENOMEM;
+       flush_dcache_page(page);
+       pte = get_locked_pte(mm, addr, &ptl);
+       if (!pte)
+               goto out_uncharge;
+       retval = -EBUSY;
+       if (!pte_none(*pte))
+               goto out_unlock;
+
+       /* Ok, finally just insert the thing.. */
+       get_page(page);
+       inc_mm_counter(mm, file_rss);
+       page_add_file_rmap(page);
+       set_pte_at(mm, addr, pte, mk_pte(page, prot));
+
+       retval = 0;
+       pte_unmap_unlock(pte, ptl);
+       return retval;
+out_unlock:
+       pte_unmap_unlock(pte, ptl);
+out_uncharge:
+       mem_cgroup_uncharge_page(page);
+out:
+       return retval;
+}
+
+/**
+ * vm_insert_page - insert single page into user vma
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @page: source kernel page
+ *
+ * This allows drivers to insert individual pages they've allocated
+ * into a user vma.
+ *
+ * The page has to be a nice clean _individual_ kernel allocation.
+ * If you allocate a compound page, you need to have marked it as
+ * such (__GFP_COMP), or manually just split the page up yourself
+ * (see split_page()).
+ *
+ * NOTE! Traditionally this was done with "remap_pfn_range()" which
+ * took an arbitrary page protection parameter. This doesn't allow
+ * that. Your vma protection will have to be set up correctly, which
+ * means that if you want a shared writable mapping, you'd better
+ * ask for a shared writable mapping!
+ *
+ * The page does not need to be reserved.
+ */
+int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
+                       struct page *page)
+{
+       if (addr < vma->vm_start || addr >= vma->vm_end)
+               return -EFAULT;
+       if (!page_count(page))
+               return -EINVAL;
+       vma->vm_flags |= VM_INSERTPAGE;
+       return insert_page(vma, addr, page, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_page);
+
+static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
+                       unsigned long pfn, pgprot_t prot)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       int retval;
+       pte_t *pte, entry;
+       spinlock_t *ptl;
+
+       retval = -ENOMEM;
+       pte = get_locked_pte(mm, addr, &ptl);
+       if (!pte)
+               goto out;
+       retval = -EBUSY;
+       if (!pte_none(*pte))
+               goto out_unlock;
+
+       /* Ok, finally just insert the thing.. */
+       entry = pte_mkspecial(pfn_pte(pfn, prot));
+       set_pte_at(mm, addr, pte, entry);
+       update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
+
+       retval = 0;
+out_unlock:
+       pte_unmap_unlock(pte, ptl);
+out:
+       return retval;
+}
+
+/**
+ * vm_insert_pfn - insert single pfn into user vma
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ *
+ * Similar to vm_inert_page, this allows drivers to insert individual pages
+ * they've allocated into a user vma. Same comments apply.
+ *
+ * This function should only be called from a vm_ops->fault handler, and
+ * in that case the handler should return NULL.
+ *
+ * vma cannot be a COW mapping.
+ *
+ * As this is called only for pages that do not currently exist, we
+ * do not need to flush old virtual caches or the TLB.
+ */
+int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
+                       unsigned long pfn)
+{
+       /*
+        * Technically, architectures with pte_special can avoid all these
+        * restrictions (same for remap_pfn_range).  However we would like
+        * consistency in testing and feature parity among all, so we should
+        * try to keep these invariants in place for everybody.
+        */
+       BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
+       BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
+                                               (VM_PFNMAP|VM_MIXEDMAP));
+       BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
+       BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
+
+       if (addr < vma->vm_start || addr >= vma->vm_end)
+               return -EFAULT;
+       return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_pfn);
+
+int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
+                       unsigned long pfn)
+{
+       BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
+
+       if (addr < vma->vm_start || addr >= vma->vm_end)
+               return -EFAULT;
+
+       /*
+        * If we don't have pte special, then we have to use the pfn_valid()
+        * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
+        * refcount the page if pfn_valid is true (hence insert_page rather
+        * than insert_pfn).
+        */
+       if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
+               struct page *page;
+
+               page = pfn_to_page(pfn);
+               return insert_page(vma, addr, page, vma->vm_page_prot);
+       }
+       return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_mixed);
+
+/*
+ * maps a range of physical memory into the requested pages. the old
+ * mappings are removed. any references to nonexistent pages results
+ * in null mappings (currently treated as "copy-on-access")
+ */
+static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
+                       unsigned long addr, unsigned long end,
+                       unsigned long pfn, pgprot_t prot)
+{
+       pte_t *pte;
+       spinlock_t *ptl;
+
+       pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+       if (!pte)
+               return -ENOMEM;
+       arch_enter_lazy_mmu_mode();
+       do {
+               BUG_ON(!pte_none(*pte));
+               set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
+               pfn++;
+       } while (pte++, addr += PAGE_SIZE, addr != end);
+       arch_leave_lazy_mmu_mode();
+       pte_unmap_unlock(pte - 1, ptl);
+       return 0;
+}
+
+static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
+                       unsigned long addr, unsigned long end,
+                       unsigned long pfn, pgprot_t prot)
+{
+       pmd_t *pmd;
+       unsigned long next;
+
+       pfn -= addr >> PAGE_SHIFT;
+       pmd = pmd_alloc(mm, pud, addr);
+       if (!pmd)
+               return -ENOMEM;
+       do {
+               next = pmd_addr_end(addr, end);
+               if (remap_pte_range(mm, pmd, addr, next,
+                               pfn + (addr >> PAGE_SHIFT), prot))
+                       return -ENOMEM;
+       } while (pmd++, addr = next, addr != end);
+       return 0;
+}
+
+static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
+                       unsigned long addr, unsigned long end,
+                       unsigned long pfn, pgprot_t prot)
+{
+       pud_t *pud;
+       unsigned long next;
+
+       pfn -= addr >> PAGE_SHIFT;
+       pud = pud_alloc(mm, pgd, addr);
+       if (!pud)
+               return -ENOMEM;
+       do {
+               next = pud_addr_end(addr, end);
+               if (remap_pmd_range(mm, pud, addr, next,
+                               pfn + (addr >> PAGE_SHIFT), prot))
+                       return -ENOMEM;
+       } while (pud++, addr = next, addr != end);
+       return 0;
+}
+
+/**
+ * remap_pfn_range - remap kernel memory to userspace
+ * @vma: user vma to map to
+ * @addr: target user address to start at
+ * @pfn: physical address of kernel memory
+ * @size: size of map area
+ * @prot: page protection flags for this mapping
+ *
+ *  Note: this is only safe if the mm semaphore is held when called.
+ */
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
+                   unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+       pgd_t *pgd;
+       unsigned long next;
+       unsigned long end = addr + PAGE_ALIGN(size);
+       struct mm_struct *mm = vma->vm_mm;
+       int err;
+
+       /*
+        * Physically remapped pages are special. Tell the
+        * rest of the world about it:
+        *   VM_IO tells people not to look at these pages
+        *      (accesses can have side effects).
+        *   VM_RESERVED is specified all over the place, because
+        *      in 2.4 it kept swapout's vma scan off this vma; but
+        *      in 2.6 the LRU scan won't even find its pages, so this
+        *      flag means no more than count its pages in reserved_vm,
+        *      and omit it from core dump, even when VM_IO turned off.
+        *   VM_PFNMAP tells the core MM that the base pages are just
+        *      raw PFN mappings, and do not have a "struct page" associated
+        *      with them.
+        *
+        * There's a horrible special case to handle copy-on-write
+        * behaviour that some programs depend on. We mark the "original"
+        * un-COW'ed pages by matching them up with "vma->vm_pgoff".
+        */
+       if (is_cow_mapping(vma->vm_flags)) {
+               if (addr != vma->vm_start || end != vma->vm_end)
+                       return -EINVAL;
+               vma->vm_pgoff = pfn;
+       }
+
+       vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
+
+       BUG_ON(addr >= end);
+       pfn -= addr >> PAGE_SHIFT;
+       pgd = pgd_offset(mm, addr);
+       flush_cache_range(vma, addr, end);
+       do {
+               next = pgd_addr_end(addr, end);
+               err = remap_pud_range(mm, pgd, addr, next,
+                               pfn + (addr >> PAGE_SHIFT), prot);
+               if (err)
+                       break;
+       } while (pgd++, addr = next, addr != end);
+       return err;
+}
+EXPORT_SYMBOL(remap_pfn_range);
+
+static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
+                                    unsigned long addr, unsigned long end,
+                                    pte_fn_t fn, void *data)
+{
+       pte_t *pte;
+       int err;
+       pgtable_t token;
+       spinlock_t *uninitialized_var(ptl);
+
+       pte = (mm == &init_mm) ?
+               pte_alloc_kernel(pmd, addr) :
+               pte_alloc_map_lock(mm, pmd, addr, &ptl);
+       if (!pte)
+               return -ENOMEM;
+
+       BUG_ON(pmd_huge(*pmd));
+
+       token = pmd_pgtable(*pmd);
+
+       do {
+               err = fn(pte, token, addr, data);
+               if (err)
+                       break;
+       } while (pte++, addr += PAGE_SIZE, addr != end);
+
+       if (mm != &init_mm)
+               pte_unmap_unlock(pte-1, ptl);
+       return err;
+}
+
+static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
+                                    unsigned long addr, unsigned long end,
+                                    pte_fn_t fn, void *data)
+{
+       pmd_t *pmd;
+       unsigned long next;
+       int err;
+
+       BUG_ON(pud_huge(*pud));
+
+       pmd = pmd_alloc(mm, pud, addr);
+       if (!pmd)
+               return -ENOMEM;
+       do {
+               next = pmd_addr_end(addr, end);
+               err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
+               if (err)
+                       break;
+       } while (pmd++, addr = next, addr != end);
+       return err;
+}
+
+static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
+                                    unsigned long addr, unsigned long end,
+                                    pte_fn_t fn, void *data)
+{
+       pud_t *pud;
+       unsigned long next;
+       int err;
+
+       pud = pud_alloc(mm, pgd, addr);
+       if (!pud)
+               return -ENOMEM;
+       do {
+               next = pud_addr_end(addr, end);
+               err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
+               if (err)
+                       break;
+       } while (pud++, addr = next, addr != end);
+       return err;
+}
+
+/*
+ * Scan a region of virtual memory, filling in page tables as necessary
+ * and calling a provided function on each leaf page table.
+ */
+int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+                       unsigned long size, pte_fn_t fn, void *data)
+{
+       pgd_t *pgd;
+       unsigned long next;
+       unsigned long start = addr, end = addr + size;
+       int err;
+
+       BUG_ON(addr >= end);
+       mmu_notifier_invalidate_range_start(mm, start, end);
+       pgd = pgd_offset(mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
+               if (err)
+                       break;
+       } while (pgd++, addr = next, addr != end);
+       mmu_notifier_invalidate_range_end(mm, start, end);
+       return err;
+}
+EXPORT_SYMBOL_GPL(apply_to_page_range);
+
+/*
+ * handle_pte_fault chooses page fault handler according to an entry
+ * which was read non-atomically.  Before making any commitment, on
+ * those architectures or configurations (e.g. i386 with PAE) which
+ * might give a mix of unmatched parts, do_swap_page and do_file_page
+ * must check under lock before unmapping the pte and proceeding
+ * (but do_wp_page is only called after already making such a check;
+ * and do_anonymous_page and do_no_page can safely check later on).
+ */
+static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
+                               pte_t *page_table, pte_t orig_pte)
+{
+       int same = 1;
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+       if (sizeof(pte_t) > sizeof(unsigned long)) {
+               spinlock_t *ptl = pte_lockptr(mm, pmd);
+               spin_lock(ptl);
+               same = pte_same(*page_table, orig_pte);
+               spin_unlock(ptl);
+       }
+#endif
+       pte_unmap(page_table);
+       return same;
+}
+
+/*
+ * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
+ * servicing faults for write access.  In the normal case, do always want
+ * pte_mkwrite.  But get_user_pages can cause write faults for mappings
+ * that do not have writing enabled, when used by access_process_vm.
+ */
+static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+       if (likely(vma->vm_flags & VM_WRITE))
+               pte = pte_mkwrite(pte);
+       return pte;
+}
+
+static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
+{
+       /*
+        * If the source page was a PFN mapping, we don't have
+        * a "struct page" for it. We do a best-effort copy by
+        * just copying from the original user address. If that
+        * fails, we just zero-fill it. Live with it.
+        */
+       if (unlikely(!src)) {
+               void *kaddr = kmap_atomic(dst, KM_USER0);
+               void __user *uaddr = (void __user *)(va & PAGE_MASK);
+
+               /*
+                * This really shouldn't fail, because the page is there
+                * in the page tables. But it might just be unreadable,
+                * in which case we just give up and fill the result with
+                * zeroes.
+                */
+               if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
+                       memset(kaddr, 0, PAGE_SIZE);
+               kunmap_atomic(kaddr, KM_USER0);
+               flush_dcache_page(dst);
+       } else
+               copy_user_highpage(dst, src, va, vma);
+}
+
+/*
+ * This routine handles present pages, when users try to write
+ * to a shared page. It is done by copying the page to a new address
+ * and decrementing the shared-page counter for the old page.
+ *
+ * Note that this routine assumes that the protection checks have been
+ * done by the caller (the low-level page fault routine in most cases).
+ * Thus we can safely just mark it writable once we've done any necessary
+ * COW.
+ *
+ * We also mark the page dirty at this point even though the page will
+ * change only once the write actually happens. This avoids a few races,
+ * and potentially makes it more efficient.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), with pte both mapped and locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pte_t *page_table, pmd_t *pmd,
+               spinlock_t *ptl, pte_t orig_pte)
+{
+       struct page *old_page, *new_page;
+       pte_t entry;
+       int reuse = 0, ret = 0;
+       int page_mkwrite = 0;
+       struct page *dirty_page = NULL;
+
+       old_page = vm_normal_page(vma, address, orig_pte);
+       if (!old_page) {
+               /*
+                * VM_MIXEDMAP !pfn_valid() case
+                *
+                * We should not cow pages in a shared writeable mapping.
+                * Just mark the pages writable as we can't do any dirty
+                * accounting on raw pfn maps.
+                */
+               if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
+                                    (VM_WRITE|VM_SHARED))
+                       goto reuse;
+               goto gotten;
+       }
+
+       /*
+        * Take out anonymous pages first, anonymous shared vmas are
+        * not dirty accountable.
+        */
+       if (PageAnon(old_page)) {
+               if (trylock_page(old_page)) {
+                       reuse = can_share_swap_page(old_page);
+                       unlock_page(old_page);
+               }
+       } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
+                                       (VM_WRITE|VM_SHARED))) {
+               /*
+                * Only catch write-faults on shared writable pages,
+                * read-only shared pages can get COWed by
+                * get_user_pages(.write=1, .force=1).
+                */
+               if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+                       /*
+                        * Notify the address space that the page is about to
+                        * become writable so that it can prohibit this or wait
+                        * for the page to get into an appropriate state.
+                        *
+                        * We do this without the lock held, so that it can
+                        * sleep if it needs to.
+                        */
+                       page_cache_get(old_page);
+                       pte_unmap_unlock(page_table, ptl);
+
+                       if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
+                               goto unwritable_page;
+
+                       /*
+                        * Since we dropped the lock we need to revalidate
+                        * the PTE as someone else may have changed it.  If
+                        * they did, we just return, as we can count on the
+                        * MMU to tell us if they didn't also make it writable.
+                        */
+                       page_table = pte_offset_map_lock(mm, pmd, address,
+                                                        &ptl);
+                       page_cache_release(old_page);
+                       if (!pte_same(*page_table, orig_pte))
+                               goto unlock;
+
+                       page_mkwrite = 1;
+               }
+               dirty_page = old_page;
+               get_page(dirty_page);
+               reuse = 1;
+       }
+
+       if (reuse) {
+reuse:
+               flush_cache_page(vma, address, pte_pfn(orig_pte));
+               entry = pte_mkyoung(orig_pte);
+               entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+               if (ptep_set_access_flags(vma, address, page_table, entry,1))
+                       update_mmu_cache(vma, address, entry);
+               ret |= VM_FAULT_WRITE;
+               goto unlock;
+       }
+
+       /*
+        * Ok, we need to copy. Oh, well..
+        */
+       page_cache_get(old_page);
+gotten:
+       pte_unmap_unlock(page_table, ptl);
+
+       if (unlikely(anon_vma_prepare(vma)))
+               goto oom;
+       VM_BUG_ON(old_page == ZERO_PAGE(0));
+       new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+       if (!new_page)
+               goto oom;
+       cow_user_page(new_page, old_page, address, vma);
+       __SetPageUptodate(new_page);
+
+       if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
+               goto oom_free_new;
+
+       /*
+        * Re-check the pte - we dropped the lock
+        */
+       page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+       if (likely(pte_same(*page_table, orig_pte))) {
+               if (old_page) {
+                       if (!PageAnon(old_page)) {
+                               dec_mm_counter(mm, file_rss);
+                               inc_mm_counter(mm, anon_rss);
+                       }
+               } else
+                       inc_mm_counter(mm, anon_rss);
+               flush_cache_page(vma, address, pte_pfn(orig_pte));
+               entry = mk_pte(new_page, vma->vm_page_prot);
+               entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+               /*
+                * Clear the pte entry and flush it first, before updating the
+                * pte with the new entry. This will avoid a race condition
+                * seen in the presence of one thread doing SMC and another
+                * thread doing COW.
+                */
+               ptep_clear_flush_notify(vma, address, page_table);
+               set_pte_at(mm, address, page_table, entry);
+               update_mmu_cache(vma, address, entry);
+               lru_cache_add_active(new_page);
+               page_add_new_anon_rmap(new_page, vma, address);
+
+               if (old_page) {
+                       /*
+                        * Only after switching the pte to the new page may
+                        * we remove the mapcount here. Otherwise another
+                        * process may come and find the rmap count decremented
+                        * before the pte is switched to the new page, and
+                        * "reuse" the old page writing into it while our pte
+                        * here still points into it and can be read by other
+                        * threads.
+                        *
+                        * The critical issue is to order this
+                        * page_remove_rmap with the ptp_clear_flush above.
+                        * Those stores are ordered by (if nothing else,)
+                        * the barrier present in the atomic_add_negative
+                        * in page_remove_rmap.
+                        *
+                        * Then the TLB flush in ptep_clear_flush ensures that
+                        * no process can access the old page before the
+                        * decremented mapcount is visible. And the old page
+                        * cannot be reused until after the decremented
+                        * mapcount is visible. So transitively, TLBs to
+                        * old page will be flushed before it can be reused.
+                        */
+                       page_remove_rmap(old_page, vma);
+               }
+
+               /* Free the old page.. */
+               new_page = old_page;
+               ret |= VM_FAULT_WRITE;
+       } else
+               mem_cgroup_uncharge_page(new_page);
+
+       if (new_page)
+               page_cache_release(new_page);
+       if (old_page)
+               page_cache_release(old_page);
+unlock:
+       pte_unmap_unlock(page_table, ptl);
+       if (dirty_page) {
+               if (vma->vm_file)
+                       file_update_time(vma->vm_file);
+
+               /*
+                * Yes, Virginia, this is actually required to prevent a race
+                * with clear_page_dirty_for_io() from clearing the page dirty
+                * bit after it clear all dirty ptes, but before a racing
+                * do_wp_page installs a dirty pte.
+                *
+                * do_no_page is protected similarly.
+                */
+               wait_on_page_locked(dirty_page);
+               set_page_dirty_balance(dirty_page, page_mkwrite);
+               put_page(dirty_page);
+       }
+       return ret;
+oom_free_new:
+       page_cache_release(new_page);
+oom:
+       if (old_page)
+               page_cache_release(old_page);
+       return VM_FAULT_OOM;
+
+unwritable_page:
+       page_cache_release(old_page);
+       return VM_FAULT_SIGBUS;
+}
+
+/*
+ * Helper functions for unmap_mapping_range().
+ *
+ * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
+ *
+ * We have to restart searching the prio_tree whenever we drop the lock,
+ * since the iterator is only valid while the lock is held, and anyway
+ * a later vma might be split and reinserted earlier while lock dropped.
+ *
+ * The list of nonlinear vmas could be handled more efficiently, using
+ * a placeholder, but handle it in the same way until a need is shown.
+ * It is important to search the prio_tree before nonlinear list: a vma
+ * may become nonlinear and be shifted from prio_tree to nonlinear list
+ * while the lock is dropped; but never shifted from list to prio_tree.
+ *
+ * In order to make forward progress despite restarting the search,
+ * vm_truncate_count is used to mark a vma as now dealt with, so we can
+ * quickly skip it next time around.  Since the prio_tree search only
+ * shows us those vmas affected by unmapping the range in question, we
+ * can't efficiently keep all vmas in step with mapping->truncate_count:
+ * so instead reset them all whenever it wraps back to 0 (then go to 1).
+ * mapping->truncate_count and vma->vm_truncate_count are protected by
+ * i_mmap_lock.
+ *
+ * In order to make forward progress despite repeatedly restarting some
+ * large vma, note the restart_addr from unmap_vmas when it breaks out:
+ * and restart from that address when we reach that vma again.  It might
+ * have been split or merged, shrunk or extended, but never shifted: so
+ * restart_addr remains valid so long as it remains in the vma's range.
+ * unmap_mapping_range forces truncate_count to leap over page-aligned
+ * values so we can save vma's restart_addr in its truncate_count field.
+ */
+#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
+
+static void reset_vma_truncate_counts(struct address_space *mapping)
+{
+       struct vm_area_struct *vma;
+       struct prio_tree_iter iter;
+
+       vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
+               vma->vm_truncate_count = 0;
+       list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+               vma->vm_truncate_count = 0;
+}
+
+static int unmap_mapping_range_vma(struct vm_area_struct *vma,
+               unsigned long start_addr, unsigned long end_addr,
+               struct zap_details *details)
+{
+       unsigned long restart_addr;
+       int need_break;
+
+       /*
+        * files that support invalidating or truncating portions of the
+        * file from under mmaped areas must have their ->fault function
+        * return a locked page (and set VM_FAULT_LOCKED in the return).
+        * This provides synchronisation against concurrent unmapping here.
+        */
+
+again:
+       restart_addr = vma->vm_truncate_count;
+       if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
+               start_addr = restart_addr;
+               if (start_addr >= end_addr) {
+                       /* Top of vma has been split off since last time */
+                       vma->vm_truncate_count = details->truncate_count;
+                       return 0;
+               }
+       }
+
+       restart_addr = zap_page_range(vma, start_addr,
+                                       end_addr - start_addr, details);
+       need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
+
+       if (restart_addr >= end_addr) {
+               /* We have now completed this vma: mark it so */
+               vma->vm_truncate_count = details->truncate_count;
+               if (!need_break)
+                       return 0;
+       } else {
+               /* Note restart_addr in vma's truncate_count field */
+               vma->vm_truncate_count = restart_addr;
+               if (!need_break)
+                       goto again;
+       }
+
+       spin_unlock(details->i_mmap_lock);
+       cond_resched();
+       spin_lock(details->i_mmap_lock);
+       return -EINTR;
+}
+
+static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
+                                           struct zap_details *details)
+{
+       struct vm_area_struct *vma;
+       struct prio_tree_iter iter;
+       pgoff_t vba, vea, zba, zea;
+
+restart:
+       vma_prio_tree_foreach(vma, &iter, root,
+                       details->first_index, details->last_index) {
+               /* Skip quickly over those we have already dealt with */
+               if (vma->vm_truncate_count == details->truncate_count)
+                       continue;
+
+               vba = vma->vm_pgoff;
+               vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
+               /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
+               zba = details->first_index;
+               if (zba < vba)
+                       zba = vba;
+               zea = details->last_index;
+               if (zea > vea)
+                       zea = vea;
+
+               if (unmap_mapping_range_vma(vma,
+                       ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
+                       ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
+                               details) < 0)
+                       goto restart;
+       }
+}
+
+static inline void unmap_mapping_range_list(struct list_head *head,
+                                           struct zap_details *details)
+{
+       struct vm_area_struct *vma;
+
+       /*
+        * In nonlinear VMAs there is no correspondence between virtual address
+        * offset and file offset.  So we must perform an exhaustive search
+        * across *all* the pages in each nonlinear VMA, not just the pages
+        * whose virtual address lies outside the file truncation point.
+        */
+restart:
+       list_for_each_entry(vma, head, shared.vm_set.list) {
+               /* Skip quickly over those we have already dealt with */
+               if (vma->vm_truncate_count == details->truncate_count)
+                       continue;
+               details->nonlinear_vma = vma;
+               if (unmap_mapping_range_vma(vma, vma->vm_start,
+                                       vma->vm_end, details) < 0)
+                       goto restart;
+       }
+}
+
+/**
+ * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
+ * @mapping: the address space containing mmaps to be unmapped.
+ * @holebegin: byte in first page to unmap, relative to the start of
+ * the underlying file.  This will be rounded down to a PAGE_SIZE
+ * boundary.  Note that this is different from vmtruncate(), which
+ * must keep the partial page.  In contrast, we must get rid of
+ * partial pages.
+ * @holelen: size of prospective hole in bytes.  This will be rounded
+ * up to a PAGE_SIZE boundary.  A holelen of zero truncates to the
+ * end of the file.
+ * @even_cows: 1 when truncating a file, unmap even private COWed pages;
+ * but 0 when invalidating pagecache, don't throw away private data.
+ */
+void unmap_mapping_range(struct address_space *mapping,
+               loff_t const holebegin, loff_t const holelen, int even_cows)
+{
+       struct zap_details details;
+       pgoff_t hba = holebegin >> PAGE_SHIFT;
+       pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+       /* Check for overflow. */
+       if (sizeof(holelen) > sizeof(hlen)) {
+               long long holeend =
+                       (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
+               if (holeend & ~(long long)ULONG_MAX)
+                       hlen = ULONG_MAX - hba + 1;
+       }
+
+       details.check_mapping = even_cows? NULL: mapping;
+       details.nonlinear_vma = NULL;
+       details.first_index = hba;
+       details.last_index = hba + hlen - 1;
+       if (details.last_index < details.first_index)
+               details.last_index = ULONG_MAX;
+       details.i_mmap_lock = &mapping->i_mmap_lock;
+
+       spin_lock(&mapping->i_mmap_lock);
+
+       /* Protect against endless unmapping loops */
+       mapping->truncate_count++;
+       if (unlikely(is_restart_addr(mapping->truncate_count))) {
+               if (mapping->truncate_count == 0)
+                       reset_vma_truncate_counts(mapping);
+               mapping->truncate_count++;
+       }
+       details.truncate_count = mapping->truncate_count;
+
+       if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
+               unmap_mapping_range_tree(&mapping->i_mmap, &details);
+       if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
+               unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
+       spin_unlock(&mapping->i_mmap_lock);
+}
+EXPORT_SYMBOL(unmap_mapping_range);
+
+/**
+ * vmtruncate - unmap mappings "freed" by truncate() syscall
+ * @inode: inode of the file used
+ * @offset: file offset to start truncating
+ *
+ * NOTE! We have to be ready to update the memory sharing
+ * between the file and the memory map for a potential last
+ * incomplete page.  Ugly, but necessary.
+ */
+int vmtruncate(struct inode * inode, loff_t offset)
+{
+       if (inode->i_size < offset) {
+               unsigned long limit;
+
+               limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+               if (limit != RLIM_INFINITY && offset > limit)
+                       goto out_sig;
+               if (offset > inode->i_sb->s_maxbytes)
+                       goto out_big;
+               i_size_write(inode, offset);
+       } else {
+               struct address_space *mapping = inode->i_mapping;
+
+               /*
+                * truncation of in-use swapfiles is disallowed - it would
+                * cause subsequent swapout to scribble on the now-freed
+                * blocks.
+                */
+               if (IS_SWAPFILE(inode))
+                       return -ETXTBSY;
+               i_size_write(inode, offset);
+
+               /*
+                * unmap_mapping_range is called twice, first simply for
+                * efficiency so that truncate_inode_pages does fewer
+                * single-page unmaps.  However after this first call, and
+                * before truncate_inode_pages finishes, it is possible for
+                * private pages to be COWed, which remain after
+                * truncate_inode_pages finishes, hence the second
+                * unmap_mapping_range call must be made for correctness.
+                */
+               unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
+               truncate_inode_pages(mapping, offset);
+               unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
+       }
+
+       if (inode->i_op && inode->i_op->truncate)
+               inode->i_op->truncate(inode);
+       return 0;
+
+out_sig:
+       send_sig(SIGXFSZ, current, 0);
+out_big:
+       return -EFBIG;
+}
+EXPORT_SYMBOL(vmtruncate);
+
+int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
+{
+       struct address_space *mapping = inode->i_mapping;
+
+       /*
+        * If the underlying filesystem is not going to provide
+        * a way to truncate a range of blocks (punch a hole) -
+        * we should return failure right now.
+        */
+       if (!inode->i_op || !inode->i_op->truncate_range)
+               return -ENOSYS;
+
+       mutex_lock(&inode->i_mutex);
+       down_write(&inode->i_alloc_sem);
+       unmap_mapping_range(mapping, offset, (end - offset), 1);
+       truncate_inode_pages_range(mapping, offset, end);
+       unmap_mapping_range(mapping, offset, (end - offset), 1);
+       inode->i_op->truncate_range(inode, offset, end);
+       up_write(&inode->i_alloc_sem);
+       mutex_unlock(&inode->i_mutex);
+
+       return 0;
+}
+
+/*
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pte_t *page_table, pmd_t *pmd,
+               int write_access, pte_t orig_pte)
+{
+       spinlock_t *ptl;
+       struct page *page;
+       swp_entry_t entry;
+       pte_t pte;
+       int ret = 0;
+
+       if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+               goto out;
+
+       entry = pte_to_swp_entry(orig_pte);
+       if (is_migration_entry(entry)) {
+               migration_entry_wait(mm, pmd, address);
+               goto out;
+       }
+       delayacct_set_flag(DELAYACCT_PF_SWAPIN);
+       page = lookup_swap_cache(entry);
+       if (!page) {
+               grab_swap_token(); /* Contend for token _before_ read-in */
+               page = swapin_readahead(entry,
+                                       GFP_HIGHUSER_MOVABLE, vma, address);
+               if (!page) {
+                       /*
+                        * Back out if somebody else faulted in this pte
+                        * while we released the pte lock.
+                        */
+                       page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+                       if (likely(pte_same(*page_table, orig_pte)))
+                               ret = VM_FAULT_OOM;
+                       delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+                       goto unlock;
+               }
+
+               /* Had to read the page from swap area: Major fault */
+               ret = VM_FAULT_MAJOR;
+               count_vm_event(PGMAJFAULT);
+       }
+
+       if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
+               delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+               ret = VM_FAULT_OOM;
+               goto out;
+       }
+
+       if (!vx_rss_avail(mm, 1)) {
+               ret = VM_FAULT_OOM;
+               goto out;
+       }
+
+       mark_page_accessed(page);
+       lock_page(page);
+       delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+
+       /*
+        * Back out if somebody else already faulted in this pte.
+        */
+       page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+       if (unlikely(!pte_same(*page_table, orig_pte)))
+               goto out_nomap;
+
+       if (unlikely(!PageUptodate(page))) {
+               ret = VM_FAULT_SIGBUS;
+               goto out_nomap;
+       }
+
+       /* The page isn't present yet, go ahead with the fault. */
+
+       inc_mm_counter(mm, anon_rss);
+       pte = mk_pte(page, vma->vm_page_prot);
+       if (write_access && can_share_swap_page(page)) {
+               pte = maybe_mkwrite(pte_mkdirty(pte), vma);
+               write_access = 0;
+       }
+
+       flush_icache_page(vma, page);
+       set_pte_at(mm, address, page_table, pte);
+       page_add_anon_rmap(page, vma, address);
+
+       swap_free(entry);
+       if (vm_swap_full())
+               remove_exclusive_swap_page(page);
+       unlock_page(page);
+
+       if (write_access) {
+               ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
+               if (ret & VM_FAULT_ERROR)
+                       ret &= VM_FAULT_ERROR;
+               goto out;
+       }
+
+       /* No need to invalidate - it was non-present before */
+       update_mmu_cache(vma, address, pte);
+unlock:
+       pte_unmap_unlock(page_table, ptl);
+out:
+       return ret;
+out_nomap:
+       mem_cgroup_uncharge_page(page);
+       pte_unmap_unlock(page_table, ptl);
+       unlock_page(page);
+       page_cache_release(page);
+       return ret;
+}
+
+/*
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pte_t *page_table, pmd_t *pmd,
+               int write_access)
+{
+       struct page *page;
+       spinlock_t *ptl;
+       pte_t entry;
+
+       /* Allocate our own private page. */
+       pte_unmap(page_table);
+
+       if (!vx_rss_avail(mm, 1))
+               goto oom;
+       if (unlikely(anon_vma_prepare(vma)))
+               goto oom;
+       page = alloc_zeroed_user_highpage_movable(vma, address);
+       if (!page)
+               goto oom;
+       __SetPageUptodate(page);
+
+       if (mem_cgroup_charge(page, mm, GFP_KERNEL))
+               goto oom_free_page;
+
+       entry = mk_pte(page, vma->vm_page_prot);
+       entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+
+       page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+       if (!pte_none(*page_table))
+               goto release;
+       inc_mm_counter(mm, anon_rss);
+       lru_cache_add_active(page);
+       page_add_new_anon_rmap(page, vma, address);
+       set_pte_at(mm, address, page_table, entry);
+
+       /* No need to invalidate - it was non-present before */
+       update_mmu_cache(vma, address, entry);
+unlock:
+       pte_unmap_unlock(page_table, ptl);
+       return 0;
+release:
+       mem_cgroup_uncharge_page(page);
+       page_cache_release(page);
+       goto unlock;
+oom_free_page:
+       page_cache_release(page);
+oom:
+       return VM_FAULT_OOM;
+}
+
+/*
+ * __do_fault() tries to create a new page mapping. It aggressively
+ * tries to share with existing pages, but makes a separate copy if
+ * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
+ * the next page fault.
+ *
+ * As this is called only for pages that do not currently exist, we
+ * do not need to flush old virtual caches or the TLB.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte neither mapped nor locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pmd_t *pmd,
+               pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
+{
+       pte_t *page_table;
+       spinlock_t *ptl;
+       struct page *page;
+       pte_t entry;
+       int anon = 0;
+       struct page *dirty_page = NULL;
+       struct vm_fault vmf;
+       int ret;
+       int page_mkwrite = 0;
+
+       vmf.virtual_address = (void __user *)(address & PAGE_MASK);
+       vmf.pgoff = pgoff;
+       vmf.flags = flags;
+       vmf.page = NULL;
+
+       ret = vma->vm_ops->fault(vma, &vmf);
+       if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
+               return ret;
+
+       /*
+        * For consistency in subsequent calls, make the faulted page always
+        * locked.
+        */
+       if (unlikely(!(ret & VM_FAULT_LOCKED)))
+               lock_page(vmf.page);
+       else
+               VM_BUG_ON(!PageLocked(vmf.page));
+
+       /*
+        * Should we do an early C-O-W break?
+        */
+       page = vmf.page;
+       if (flags & FAULT_FLAG_WRITE) {
+               if (!(vma->vm_flags & VM_SHARED)) {
+                       anon = 1;
+                       if (unlikely(anon_vma_prepare(vma))) {
+                               ret = VM_FAULT_OOM;
+                               goto out;
+                       }
+                       page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
+                                               vma, address);
+                       if (!page) {
+                               ret = VM_FAULT_OOM;
+                               goto out;
+                       }
+                       copy_user_highpage(page, vmf.page, address, vma);
+                       __SetPageUptodate(page);
+               } else {
+                       /*
+                        * If the page will be shareable, see if the backing
+                        * address space wants to know that the page is about
+                        * to become writable
+                        */
+                       if (vma->vm_ops->page_mkwrite) {
+                               unlock_page(page);
+                               if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
+                                       ret = VM_FAULT_SIGBUS;
+                                       anon = 1; /* no anon but release vmf.page */
+                                       goto out_unlocked;
+                               }
+                               lock_page(page);
+                               /*
+                                * XXX: this is not quite right (racy vs
+                                * invalidate) to unlock and relock the page
+                                * like this, however a better fix requires
+                                * reworking page_mkwrite locking API, which
+                                * is better done later.
+                                */
+                               if (!page->mapping) {
+                                       ret = 0;
+                                       anon = 1; /* no anon but release vmf.page */
+                                       goto out;
+                               }
+                               page_mkwrite = 1;
+                       }
+               }
+
+       }
+
+       if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
+               ret = VM_FAULT_OOM;
+               goto out;
+       }
+
+       page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+
+       /*
+        * This silly early PAGE_DIRTY setting removes a race
+        * due to the bad i386 page protection. But it's valid
+        * for other architectures too.
+        *
+        * Note that if write_access is true, we either now have
+        * an exclusive copy of the page, or this is a shared mapping,
+        * so we can make it writable and dirty to avoid having to
+        * handle that later.
+        */
+       /* Only go through if we didn't race with anybody else... */
+       if (likely(pte_same(*page_table, orig_pte))) {
+               flush_icache_page(vma, page);
+               entry = mk_pte(page, vma->vm_page_prot);
+               if (flags & FAULT_FLAG_WRITE)
+                       entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+               set_pte_at(mm, address, page_table, entry);
+               if (anon) {
+                        inc_mm_counter(mm, anon_rss);
+                        lru_cache_add_active(page);
+                        page_add_new_anon_rmap(page, vma, address);
+               } else {
+                       inc_mm_counter(mm, file_rss);
+                       page_add_file_rmap(page);
+                       if (flags & FAULT_FLAG_WRITE) {
+                               dirty_page = page;
+                               get_page(dirty_page);
+                       }
+               }
+
+               /* no need to invalidate: a not-present page won't be cached */
+               update_mmu_cache(vma, address, entry);
+       } else {
+               mem_cgroup_uncharge_page(page);
+               if (anon)
+                       page_cache_release(page);
+               else
+                       anon = 1; /* no anon but release faulted_page */
+       }
+
+       pte_unmap_unlock(page_table, ptl);
+
+out:
+       unlock_page(vmf.page);
+out_unlocked:
+       if (anon)
+               page_cache_release(vmf.page);
+       else if (dirty_page) {
+               if (vma->vm_file)
+                       file_update_time(vma->vm_file);
+
+               set_page_dirty_balance(dirty_page, page_mkwrite);
+               put_page(dirty_page);
+       }
+
+       return ret;
+}
+
+static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pte_t *page_table, pmd_t *pmd,
+               int write_access, pte_t orig_pte)
+{
+       pgoff_t pgoff = (((address & PAGE_MASK)
+                       - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+       unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
+
+       pte_unmap(page_table);
+       return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
+}
+
+/*
+ * Fault of a previously existing named mapping. Repopulate the pte
+ * from the encoded file_pte if possible. This enables swappable
+ * nonlinear vmas.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, pte_t *page_table, pmd_t *pmd,
+               int write_access, pte_t orig_pte)
+{
+       unsigned int flags = FAULT_FLAG_NONLINEAR |
+                               (write_access ? FAULT_FLAG_WRITE : 0);
+       pgoff_t pgoff;
+
+       if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+               return 0;
+
+       if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
+                       !(vma->vm_flags & VM_CAN_NONLINEAR))) {
+               /*
+                * Page table corrupted: show pte and kill process.
+                */
+               print_bad_pte(vma, orig_pte, address);
+               return VM_FAULT_OOM;
+       }
+
+       pgoff = pte_to_pgoff(orig_pte);
+       return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
+}
+
+/*
+ * These routines also need to handle stuff like marking pages dirty
+ * and/or accessed for architectures that don't do it in hardware (most
+ * RISC architectures).  The early dirtying is also good on the i386.
+ *
+ * There is also a hook called "update_mmu_cache()" that architectures
+ * with external mmu caches can use to update those (ie the Sparc or
+ * PowerPC hashed page tables that act as extended TLBs).
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+ */
+static inline int handle_pte_fault(struct mm_struct *mm,
+               struct vm_area_struct *vma, unsigned long address,
+               pte_t *pte, pmd_t *pmd, int write_access)
+{
+       pte_t entry;
+       spinlock_t *ptl;
+       int ret = 0, type = VXPT_UNKNOWN;
+
+       entry = *pte;
+       if (!pte_present(entry)) {
+               if (pte_none(entry)) {
+                       if (vma->vm_ops) {
+                               if (likely(vma->vm_ops->fault))
+                                       return do_linear_fault(mm, vma, address,
+                                               pte, pmd, write_access, entry);
+                       }
+                       return do_anonymous_page(mm, vma, address,
+                                                pte, pmd, write_access);
+               }
+               if (pte_file(entry))
+                       return do_nonlinear_fault(mm, vma, address,
+                                       pte, pmd, write_access, entry);
+               return do_swap_page(mm, vma, address,
+                                       pte, pmd, write_access, entry);
+       }
+
+       ptl = pte_lockptr(mm, pmd);
+       spin_lock(ptl);
+       if (unlikely(!pte_same(*pte, entry)))
+               goto unlock;
+       if (write_access) {
+               if (!pte_write(entry)) {
+                       ret = do_wp_page(mm, vma, address,
+                                       pte, pmd, ptl, entry);
+                       type = VXPT_WRITE;
+                       goto out;
+               }
+               entry = pte_mkdirty(entry);
+       }
+       entry = pte_mkyoung(entry);
+       if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
+               update_mmu_cache(vma, address, entry);
+       } else {
+               /*
+                * This is needed only for protection faults but the arch code
+                * is not yet telling us if this is a protection fault or not.
+                * This still avoids useless tlb flushes for .text page faults
+                * with threads.
+                */
+               if (write_access)
+                       flush_tlb_page(vma, address);
+       }
+unlock:
+       pte_unmap_unlock(pte, ptl);
+       ret = 0;
+out:
+       vx_page_fault(mm, vma, type, ret);
+       return ret;
+}
+
+/*
+ * By the time we get here, we already hold the mm semaphore
+ */
+int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+               unsigned long address, int write_access)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *pte;
+
+       __set_current_state(TASK_RUNNING);
+
+       count_vm_event(PGFAULT);
+
+       if (unlikely(is_vm_hugetlb_page(vma)))
+               return hugetlb_fault(mm, vma, address, write_access);
+
+       pgd = pgd_offset(mm, address);
+       pud = pud_alloc(mm, pgd, address);
+       if (!pud)
+               return VM_FAULT_OOM;
+       pmd = pmd_alloc(mm, pud, address);
+       if (!pmd)
+               return VM_FAULT_OOM;
+       pte = pte_alloc_map(mm, pmd, address);
+       if (!pte)
+               return VM_FAULT_OOM;
+
+       return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
+}
+
+#ifndef __PAGETABLE_PUD_FOLDED
+/*
+ * Allocate page upper directory.
+ * We've already handled the fast-path in-line.
+ */
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+{
+       pud_t *new = pud_alloc_one(mm, address);
+       if (!new)
+               return -ENOMEM;
+
+       smp_wmb(); /* See comment in __pte_alloc */
+
+       spin_lock(&mm->page_table_lock);
+       if (pgd_present(*pgd))          /* Another has populated it */
+               pud_free(mm, new);
+       else
+               pgd_populate(mm, pgd, new);
+       spin_unlock(&mm->page_table_lock);
+       return 0;
+}
+#endif /* __PAGETABLE_PUD_FOLDED */
+
+#ifndef __PAGETABLE_PMD_FOLDED
+/*
+ * Allocate page middle directory.
+ * We've already handled the fast-path in-line.
+ */
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+{
+       pmd_t *new = pmd_alloc_one(mm, address);
+       if (!new)
+               return -ENOMEM;
+
+       smp_wmb(); /* See comment in __pte_alloc */
+
+       spin_lock(&mm->page_table_lock);
+#ifndef __ARCH_HAS_4LEVEL_HACK
+       if (pud_present(*pud))          /* Another has populated it */
+               pmd_free(mm, new);
+       else
+               pud_populate(mm, pud, new);
+#else
+       if (pgd_present(*pud))          /* Another has populated it */
+               pmd_free(mm, new);
+       else
+               pgd_populate(mm, pud, new);
+#endif /* __ARCH_HAS_4LEVEL_HACK */
+       spin_unlock(&mm->page_table_lock);
+       return 0;
+}
+#endif /* __PAGETABLE_PMD_FOLDED */
+
+int make_pages_present(unsigned long addr, unsigned long end)
+{
+       int ret, len, write;
+       struct vm_area_struct * vma;
+
+       vma = find_vma(current->mm, addr);
+       if (!vma)
+               return -ENOMEM;
+       write = (vma->vm_flags & VM_WRITE) != 0;
+       BUG_ON(addr >= end);
+       BUG_ON(end > vma->vm_end);
+       len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
+       ret = get_user_pages(current, current->mm, addr,
+                       len, write, 0, NULL, NULL);
+       if (ret < 0) {
+               /*
+                  SUS require strange return value to mlock
+                   - invalid addr generate to ENOMEM.
+                   - out of memory should generate EAGAIN.
+               */
+               if (ret == -EFAULT)
+                       ret = -ENOMEM;
+               else if (ret == -ENOMEM)
+                       ret = -EAGAIN;
+               return ret;
+       }
+       return ret == len ? 0 : -ENOMEM;
+}
+
+#if !defined(__HAVE_ARCH_GATE_AREA)
+
+#if defined(AT_SYSINFO_EHDR)
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+       gate_vma.vm_mm = NULL;
+       gate_vma.vm_start = FIXADDR_USER_START;
+       gate_vma.vm_end = FIXADDR_USER_END;
+       gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+       gate_vma.vm_page_prot = __P101;
+       /*
+        * Make sure the vDSO gets into every core dump.
+        * Dumping its contents makes post-mortem fully interpretable later
+        * without matching up the same kernel and hardware config to see
+        * what PC values meant.
+        */
+       gate_vma.vm_flags |= VM_ALWAYSDUMP;
+       return 0;
+}
+__initcall(gate_vma_init);
+#endif
+
+struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
+{
+#ifdef AT_SYSINFO_EHDR
+       return &gate_vma;
+#else
+       return NULL;
+#endif
+}
+
+int in_gate_area_no_task(unsigned long addr)
+{
+#ifdef AT_SYSINFO_EHDR
+       if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+               return 1;
+#endif
+       return 0;
+}
+
+#endif /* __HAVE_ARCH_GATE_AREA */
+
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+static resource_size_t follow_phys(struct vm_area_struct *vma,
+                       unsigned long address, unsigned int flags,
+                       unsigned long *prot)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *ptep, pte;
+       spinlock_t *ptl;
+       resource_size_t phys_addr = 0;
+       struct mm_struct *mm = vma->vm_mm;
+
+       VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP)));
+
+       pgd = pgd_offset(mm, address);
+       if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+               goto no_page_table;
+
+       pud = pud_offset(pgd, address);
+       if (pud_none(*pud) || unlikely(pud_bad(*pud)))
+               goto no_page_table;
+
+       pmd = pmd_offset(pud, address);
+       if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+               goto no_page_table;
+
+       /* We cannot handle huge page PFN maps. Luckily they don't exist. */
+       if (pmd_huge(*pmd))
+               goto no_page_table;
+
+       ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+       if (!ptep)
+               goto out;
+
+       pte = *ptep;
+       if (!pte_present(pte))
+               goto unlock;
+       if ((flags & FOLL_WRITE) && !pte_write(pte))
+               goto unlock;
+       phys_addr = pte_pfn(pte);
+       phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
+
+       *prot = pgprot_val(pte_pgprot(pte));
+
+unlock:
+       pte_unmap_unlock(ptep, ptl);
+out:
+       return phys_addr;
+no_page_table:
+       return 0;
+}
+
+int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
+                       void *buf, int len, int write)
+{
+       resource_size_t phys_addr;
+       unsigned long prot = 0;
+       void *maddr;
+       int offset = addr & (PAGE_SIZE-1);
+
+       if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+               return -EINVAL;
+
+       phys_addr = follow_phys(vma, addr, write, &prot);
+
+       if (!phys_addr)
+               return -EINVAL;
+
+       maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
+       if (write)
+               memcpy_toio(maddr + offset, buf, len);
+       else
+               memcpy_fromio(buf, maddr + offset, len);
+       iounmap(maddr);
+
+       return len;
+}
+#endif
+
+/*
+ * Access another process' address space.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+       struct mm_struct *mm;
+       struct vm_area_struct *vma;
+       void *old_buf = buf;
+
+       mm = get_task_mm(tsk);
+       if (!mm)
+               return 0;
+
+       down_read(&mm->mmap_sem);
+       /* ignore errors, just check how much was successfully transferred */
+       while (len) {
+               int bytes, ret, offset;
+               void *maddr;
+               struct page *page = NULL;
+
+               ret = get_user_pages(tsk, mm, addr, 1,
+                               write, 1, &page, &vma);
+               if (ret <= 0) {
+                       /*
+                        * Check if this is a VM_IO | VM_PFNMAP VMA, which
+                        * we can access using slightly different code.
+                        */
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+                       vma = find_vma(mm, addr);
+                       if (!vma)
+                               break;
+                       if (vma->vm_ops && vma->vm_ops->access)
+                               ret = vma->vm_ops->access(vma, addr, buf,
+                                                         len, write);
+                       if (ret <= 0)
+#endif
+                               break;
+                       bytes = ret;
+               } else {
+                       bytes = len;
+                       offset = addr & (PAGE_SIZE-1);
+                       if (bytes > PAGE_SIZE-offset)
+                               bytes = PAGE_SIZE-offset;
+
+                       maddr = kmap(page);
+                       if (write) {
+                               copy_to_user_page(vma, page, addr,
+                                                 maddr + offset, buf, bytes);
+                               set_page_dirty_lock(page);
+                       } else {
+                               copy_from_user_page(vma, page, addr,
+                                                   buf, maddr + offset, bytes);
+                       }
+                       kunmap(page);
+                       page_cache_release(page);
+               }
+               len -= bytes;
+               buf += bytes;
+               addr += bytes;
+       }
+       up_read(&mm->mmap_sem);
+       mmput(mm);
+
+       return buf - old_buf;
+}
+
+/*
+ * Print the name of a VMA.
+ */
+void print_vma_addr(char *prefix, unsigned long ip)
+{
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+
+       /*
+        * Do not print if we are in atomic
+        * contexts (in exception stacks, etc.):
+        */
+       if (preempt_count())
+               return;
+
+       down_read(&mm->mmap_sem);
+       vma = find_vma(mm, ip);
+       if (vma && vma->vm_file) {
+               struct file *f = vma->vm_file;
+               char *buf = (char *)__get_free_page(GFP_KERNEL);
+               if (buf) {
+                       char *p, *s;
+
+                       p = d_path(&f->f_path, buf, PAGE_SIZE);
+                       if (IS_ERR(p))
+                               p = "?";
+                       s = strrchr(p, '/');
+                       if (s)
+                               p = s+1;
+                       printk("%s%s[%lx+%lx]", prefix, p,
+                                       vma->vm_start,
+                                       vma->vm_end - vma->vm_start);
+                       free_page((unsigned long)buf);
+               }
+       }
+       up_read(&current->mm->mmap_sem);
+}
diff -Nurb linux-2.6.27-590/mm/slab.c linux-2.6.27-591/mm/slab.c
--- linux-2.6.27-590/mm/slab.c  2010-02-01 19:42:07.000000000 -0500
+++ linux-2.6.27-591/mm/slab.c  2010-02-01 19:43:07.000000000 -0500
@@ -110,6 +110,7 @@
 #include       <linux/fault-inject.h>
 #include       <linux/rtmutex.h>
 #include       <linux/reciprocal_div.h>
+#include <linux/arrays.h>
 #include       <linux/debugobjects.h>
 
 #include       <asm/cacheflush.h>
@@ -248,6 +249,14 @@
        void *addr;
 };
 
+extern void (*rec_event)(void *,unsigned int);
+struct event_spec {
+       unsigned long pc;
+       unsigned long dcookie; 
+       unsigned count;
+       unsigned char reason;
+};
+
 /*
  * struct array_cache
  *
@@ -3469,6 +3478,19 @@
        local_irq_restore(save_flags);
        objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
        prefetchw(objp);
+#ifdef CONFIG_CHOPSTIX
+       if (rec_event && objp) {
+               struct event event;
+               struct event_spec espec;
+
+               espec.reason = 0; /* alloc */
+               event.event_data=&espec;
+               event.task = current;
+               espec.pc=caller;
+               event.event_type=5; 
+               (*rec_event)(&event, cachep->buffer_size);
+       }
+#endif
 
        if (unlikely((flags & __GFP_ZERO) && objp))
                memset(objp, 0, obj_size(cachep));
@@ -3578,12 +3600,26 @@
  * Release an obj back to its cache. If the obj has a constructed state, it must
  * be in this state _before_ it is released.  Called with disabled ints.
  */
-static inline void __cache_free(struct kmem_cache *cachep, void *objp)
+static inline void __cache_free(struct kmem_cache *cachep, void *objp, void *caller)
 {
        struct array_cache *ac = cpu_cache_get(cachep);
 
        check_irq_off();
-       objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
+       objp = cache_free_debugcheck(cachep, objp, caller);
+ #ifdef CONFIG_CHOPSTIX
+       if (rec_event && objp) {
+               struct event event;
+               struct event_spec espec;
+  
+               espec.reason = 1; /* free */
+               event.event_data=&espec;
+               event.task = current;
+               espec.pc=caller;
+               event.event_type=4; 
+               (*rec_event)(&event, cachep->buffer_size);
+       }
+ #endif
+
        vx_slab_free(cachep);
 
        /*
@@ -3714,6 +3750,7 @@
                                          void *caller)
 {
        struct kmem_cache *cachep;
+       void *ret;
 
        /* If you want to save a few bytes .text space: replace
         * __ with kmem_.
@@ -3741,10 +3778,17 @@
 EXPORT_SYMBOL(__kmalloc_track_caller);
 
 #else
+#ifdef CONFIG_CHOPSTIX
+void *__kmalloc(size_t size, gfp_t flags)
+{
+       return __do_kmalloc(size, flags, __builtin_return_address(0));
+}
+#else
 void *__kmalloc(size_t size, gfp_t flags)
 {
        return __do_kmalloc(size, flags, NULL);
 }
+#endif
 EXPORT_SYMBOL(__kmalloc);
 #endif
 
@@ -3764,7 +3808,7 @@
        debug_check_no_locks_freed(objp, obj_size(cachep));
        if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
                debug_check_no_obj_freed(objp, obj_size(cachep));
-       __cache_free(cachep, objp);
+       __cache_free(cachep, objp,__builtin_return_address(0));
        local_irq_restore(flags);
 }
 EXPORT_SYMBOL(kmem_cache_free);
@@ -3790,7 +3834,7 @@
        c = virt_to_cache(objp);
        debug_check_no_locks_freed(objp, obj_size(c));
        debug_check_no_obj_freed(objp, obj_size(c));
-       __cache_free(c, (void *)objp);
+       __cache_free(c, (void *)objp,__builtin_return_address(0));
        local_irq_restore(flags);
 }
 EXPORT_SYMBOL(kfree);