* 2003-09-03 Interactivity tuning by Con Kolivas.
* 2004-04-02 Scheduler domains code by Nick Piggin
*/
+
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/nmi.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/security.h>
#include <linux/notifier.h>
#include <linux/profile.h>
#include <linux/suspend.h>
+#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/delay.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/syscalls.h>
#include <linux/times.h>
-#include <linux/vserver/sched.h>
-#include <linux/vs_base.h>
-#include <linux/vs_context.h>
-#include <linux/vs_cvirt.h>
+#include <linux/acct.h>
#include <asm/tlb.h>
-
#include <asm/unistd.h>
-#ifdef CONFIG_NUMA
-#define cpu_to_node_mask(cpu) node_to_cpumask(cpu_to_node(cpu))
-#else
-#define cpu_to_node_mask(cpu) (cpu_online_map)
-#endif
-
-/* used to soft spin in sched while dump is in progress */
-unsigned long dump_oncpu;
-EXPORT_SYMBOL(dump_oncpu);
+#include <linux/vs_context.h>
+#include <linux/vs_cvirt.h>
+#include <linux/vs_sched.h>
/*
* Convert user-nice values [ -20 ... 0 ... 19 ]
#define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS)
#define STARVATION_LIMIT (MAX_SLEEP_AVG)
#define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG))
-#define CREDIT_LIMIT 100
/*
* If a task is 'interactive' then we reinsert it in the active
(NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \
MAX_SLEEP_AVG)
+#define GRANULARITY (10 * HZ / 1000 ? : 1)
+
#ifdef CONFIG_SMP
-#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \
+#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \
(1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \
num_online_cpus())
#else
-#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \
+#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \
(1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)))
#endif
(JIFFIES_TO_NS(MAX_SLEEP_AVG * \
(MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1))
-#define HIGH_CREDIT(p) \
- ((p)->interactive_credit > CREDIT_LIMIT)
-
-#define LOW_CREDIT(p) \
- ((p)->interactive_credit < -CREDIT_LIMIT)
-
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
-/*
- * if belong to different class, compare class priority
- * otherwise compare task priority
- */
-#define TASK_PREEMPTS_CURR(p, rq) \
- ( ((p)->cpu_class != (rq)->curr->cpu_class) \
- && ((rq)->curr != (rq)->idle) && ((p) != (rq)->idle )) \
- ? class_preempts_curr((p),(rq)->curr) \
- : ((p)->prio < (rq)->curr->prio)
-#else
#define TASK_PREEMPTS_CURR(p, rq) \
((p)->prio < (rq)->curr->prio)
-#endif
/*
* task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
#define SCALE_PRIO(x, prio) \
max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE)
-unsigned int task_timeslice(task_t *p)
+static unsigned int task_timeslice(task_t *p)
{
if (p->static_prio < NICE_TO_PRIO(0))
return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio);
* These are the runqueue data structures:
*/
+#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
+
typedef struct runqueue runqueue_t;
-#include <linux/ckrm_classqueue.h>
-#include <linux/ckrm_sched.h>
+
+struct prio_array {
+ unsigned int nr_active;
+ unsigned long bitmap[BITMAP_SIZE];
+ struct list_head queue[MAX_PRIO];
+};
/*
* This is the main, per-CPU runqueue data structure.
*/
unsigned long nr_running;
#ifdef CONFIG_SMP
- unsigned long cpu_load;
+ unsigned long cpu_load[3];
#endif
unsigned long long nr_switches;
unsigned long long timestamp_last_tick;
task_t *curr, *idle;
struct mm_struct *prev_mm;
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- struct classqueue_struct classqueue;
- ckrm_load_t ckrm_load;
-#else
- prio_array_t *active, *expired, arrays[2];
-#endif
+ prio_array_t *active, *expired, arrays[2];
int best_expired_prio;
atomic_t nr_iowait;
task_t *migration_thread;
struct list_head migration_queue;
+ int cpu;
#endif
-
#ifdef CONFIG_VSERVER_HARDCPU
struct list_head hold_queue;
int idle_tokens;
unsigned long yld_cnt;
/* schedule() stats */
- unsigned long sched_noswitch;
unsigned long sched_switch;
unsigned long sched_cnt;
unsigned long sched_goidle;
- /* pull_task() stats */
- unsigned long pt_gained[MAX_IDLE_TYPES];
- unsigned long pt_lost[MAX_IDLE_TYPES];
-
- /* active_load_balance() stats */
- unsigned long alb_cnt;
- unsigned long alb_lost;
- unsigned long alb_gained;
- unsigned long alb_failed;
-
/* try_to_wake_up() stats */
unsigned long ttwu_cnt;
- unsigned long ttwu_attempts;
- unsigned long ttwu_moved;
-
- /* wake_up_new_task() stats */
- unsigned long wunt_cnt;
- unsigned long wunt_moved;
-
- /* sched_migrate_task() stats */
- unsigned long smt_cnt;
-
- /* sched_balance_exec() stats */
- unsigned long sbe_cnt;
+ unsigned long ttwu_local;
#endif
};
static DEFINE_PER_CPU(struct runqueue, runqueues);
+/*
+ * 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, domain) \
- for (domain = cpu_rq(cpu)->sd; domain; domain = domain->parent)
+for (domain = rcu_dereference(cpu_rq(cpu)->sd); domain; domain = domain->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)
-/*
- * Default context-switch locking:
- */
#ifndef prepare_arch_switch
-# define prepare_arch_switch(rq, next) do { } while (0)
-# define finish_arch_switch(rq, next) spin_unlock_irq(&(rq)->lock)
-# define task_running(rq, p) ((rq)->curr == (p))
+# define prepare_arch_switch(next) do { } while (0)
+#endif
+#ifndef finish_arch_switch
+# define finish_arch_switch(prev) do { } while (0)
+#endif
+
+#ifndef __ARCH_WANT_UNLOCKED_CTXSW
+static inline int task_running(runqueue_t *rq, task_t *p)
+{
+ return rq->curr == p;
+}
+
+static inline void prepare_lock_switch(runqueue_t *rq, task_t *next)
+{
+}
+
+static inline void finish_lock_switch(runqueue_t *rq, task_t *prev)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+ /* this is a valid case when another task releases the spinlock */
+ rq->lock.owner = current;
+#endif
+ spin_unlock_irq(&rq->lock);
+}
+
+#else /* __ARCH_WANT_UNLOCKED_CTXSW */
+static inline int task_running(runqueue_t *rq, task_t *p)
+{
+#ifdef CONFIG_SMP
+ return p->oncpu;
+#else
+ return rq->curr == p;
+#endif
+}
+
+static inline void prepare_lock_switch(runqueue_t *rq, task_t *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(runqueue_t *rq, task_t *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 and disable
* interrupts. Note the ordering: we can safely lookup the task_rq without
* explicitly disabling preemption.
*/
-static runqueue_t *task_rq_lock(task_t *p, unsigned long *flags)
+static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags)
__acquires(rq->lock)
{
struct runqueue *rq;
* bump this up when changing the output format or the meaning of an existing
* format, so that tools can adapt (or abort)
*/
-#define SCHEDSTAT_VERSION 10
+#define SCHEDSTAT_VERSION 12
static int show_schedstat(struct seq_file *seq, void *v)
{
int cpu;
- enum idle_type itype;
seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
seq_printf(seq, "timestamp %lu\n", jiffies);
/* runqueue-specific stats */
seq_printf(seq,
- "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu "
- "%lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+ "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
cpu, rq->yld_both_empty,
- rq->yld_act_empty, rq->yld_exp_empty,
- rq->yld_cnt, rq->sched_noswitch,
+ rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt,
rq->sched_switch, rq->sched_cnt, rq->sched_goidle,
- rq->alb_cnt, rq->alb_gained, rq->alb_lost,
- rq->alb_failed,
- rq->ttwu_cnt, rq->ttwu_moved, rq->ttwu_attempts,
- rq->wunt_cnt, rq->wunt_moved,
- rq->smt_cnt, rq->sbe_cnt, rq->rq_sched_info.cpu_time,
+ rq->ttwu_cnt, rq->ttwu_local,
+ rq->rq_sched_info.cpu_time,
rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt);
- for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; itype++)
- seq_printf(seq, " %lu %lu", rq->pt_gained[itype],
- rq->pt_lost[itype]);
seq_printf(seq, "\n");
#ifdef CONFIG_SMP
/* domain-specific stats */
+ preempt_disable();
for_each_domain(cpu, sd) {
+ enum idle_type itype;
char mask_str[NR_CPUS];
cpumask_scnprintf(mask_str, NR_CPUS, sd->span);
seq_printf(seq, "domain%d %s", dcnt++, mask_str);
for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES;
- itype++) {
- seq_printf(seq, " %lu %lu %lu %lu %lu",
+ itype++) {
+ seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu",
sd->lb_cnt[itype],
+ sd->lb_balanced[itype],
sd->lb_failed[itype],
sd->lb_imbalance[itype],
+ sd->lb_gained[itype],
+ sd->lb_hot_gained[itype],
sd->lb_nobusyq[itype],
sd->lb_nobusyg[itype]);
}
- seq_printf(seq, " %lu %lu %lu %lu\n",
- sd->sbe_pushed, sd->sbe_attempts,
- sd->ttwu_wake_affine, sd->ttwu_wake_balance);
+ seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
+ sd->alb_cnt, sd->alb_failed, sd->alb_pushed,
+ sd->sbe_cnt, sd->sbe_balanced, sd->sbe_pushed,
+ sd->sbf_cnt, sd->sbf_balanced, sd->sbf_pushed,
+ sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance);
}
+ preempt_enable();
#endif
}
return 0;
.release = single_release,
};
-# define schedstat_inc(rq, field) rq->field++;
-# define schedstat_add(rq, field, amt) rq->field += amt;
+# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
+# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
#else /* !CONFIG_SCHEDSTATS */
-# define schedstat_inc(rq, field) do { } while (0);
-# define schedstat_add(rq, field, amt) do { } while (0);
+# define schedstat_inc(rq, field) do { } while (0)
+# define schedstat_add(rq, field, amt) do { } while (0)
#endif
/*
* rq_lock - lock a given runqueue and disable interrupts.
*/
-static runqueue_t *this_rq_lock(void)
+static inline runqueue_t *this_rq_lock(void)
__acquires(rq->lock)
{
runqueue_t *rq;
return rq;
}
-static inline void rq_unlock(runqueue_t *rq)
- __releases(rq->lock)
-{
- spin_unlock_irq(&rq->lock);
-}
-
#ifdef CONFIG_SCHEDSTATS
/*
* Called when a process is dequeued from the active array and given
* long it was waiting to run. We also note when it began so that we
* can keep stats on how long its timeslice is.
*/
-static inline void sched_info_arrive(task_t *t)
+static void sched_info_arrive(task_t *t)
{
unsigned long now = jiffies, diff = 0;
struct runqueue *rq = task_rq(t);
#define sched_info_switch(t, next) do { } while (0)
#endif /* CONFIG_SCHEDSTATS */
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
-static inline ckrm_lrq_t *rq_get_next_class(struct runqueue *rq)
-{
- cq_node_t *node = classqueue_get_head(&rq->classqueue);
- return ((node) ? class_list_entry(node) : NULL);
-}
-
-/*
- * return the cvt of the current running class
- * if no current running class, return 0
- * assume cpu is valid (cpu_online(cpu) == 1)
- */
-CVT_t get_local_cur_cvt(int cpu)
-{
- ckrm_lrq_t * lrq = rq_get_next_class(cpu_rq(cpu));
-
- if (lrq)
- return lrq->local_cvt;
- else
- return 0;
-}
-
-static inline struct task_struct * rq_get_next_task(struct runqueue* rq)
-{
- prio_array_t *array;
- struct task_struct *next;
- ckrm_lrq_t *queue;
- int idx;
- int cpu = smp_processor_id();
-
- // it is guaranteed be the ( rq->nr_running > 0 ) check in
- // schedule that a task will be found.
-
- retry_next_class:
- queue = rq_get_next_class(rq);
- // BUG_ON( !queue );
-
- array = queue->active;
- if (unlikely(!array->nr_active)) {
- queue->active = queue->expired;
- queue->expired = array;
- queue->expired_timestamp = 0;
-
- schedstat_inc(rq, sched_switch);
- if (queue->active->nr_active)
- set_top_priority(queue,
- find_first_bit(queue->active->bitmap, MAX_PRIO));
- else {
- classqueue_dequeue(queue->classqueue,
- &queue->classqueue_linkobj);
- cpu_demand_event(get_rq_local_stat(queue,cpu),CPU_DEMAND_DEQUEUE,0);
- }
- goto retry_next_class;
- } else
- schedstat_inc(rq, sched_noswitch);
- // BUG_ON(!array->nr_active);
-
- idx = queue->top_priority;
- // BUG_ON (idx == MAX_PRIO);
- next = task_list_entry(array->queue[idx].next);
- return next;
-}
-#else /*! CONFIG_CKRM_CPU_SCHEDULE*/
-static inline struct task_struct * rq_get_next_task(struct runqueue* rq)
-{
- prio_array_t *array;
- struct list_head *queue;
- int idx;
-
- array = rq->active;
- if (unlikely(!array->nr_active)) {
- /*
- * Switch the active and expired arrays.
- */
- schedstat_inc(rq, sched_switch);
- rq->active = rq->expired;
- rq->expired = array;
- array = rq->active;
- rq->expired_timestamp = 0;
- rq->best_expired_prio = MAX_PRIO;
- } else
- schedstat_inc(rq, sched_noswitch);
-
- idx = sched_find_first_bit(array->bitmap);
- queue = array->queue + idx;
- return list_entry(queue->next, task_t, run_list);
-}
-
-static inline void class_enqueue_task(struct task_struct* p, prio_array_t *array) { }
-static inline void class_dequeue_task(struct task_struct* p, prio_array_t *array) { }
-static inline void init_cpu_classes(void) { }
-#define rq_ckrm_load(rq) NULL
-static inline void ckrm_sched_tick(int j,int this_cpu,void* name) {}
-#endif /* CONFIG_CKRM_CPU_SCHEDULE */
-
/*
* Adding/removing a task to/from a priority array:
*/
static void dequeue_task(struct task_struct *p, prio_array_t *array)
{
+ BUG_ON(p->state & TASK_ONHOLD);
array->nr_active--;
list_del(&p->run_list);
if (list_empty(array->queue + p->prio))
__clear_bit(p->prio, array->bitmap);
- class_dequeue_task(p,array);
}
static void enqueue_task(struct task_struct *p, prio_array_t *array)
{
+ BUG_ON(p->state & TASK_ONHOLD);
sched_info_queued(p);
list_add_tail(&p->run_list, array->queue + p->prio);
__set_bit(p->prio, array->bitmap);
array->nr_active++;
p->array = array;
- class_enqueue_task(p,array);
}
/*
- * Used by the migration code - we pull tasks from the head of the
- * remote queue so we want these tasks to show up at the head of the
- * local queue:
+ * Put task to the end of the run list without the overhead of dequeue
+ * followed by enqueue.
*/
+static void requeue_task(struct task_struct *p, prio_array_t *array)
+{
+ BUG_ON(p->state & TASK_ONHOLD);
+ list_move_tail(&p->run_list, array->queue + p->prio);
+}
+
static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array)
{
+ BUG_ON(p->state & TASK_ONHOLD);
list_add(&p->run_list, array->queue + p->prio);
__set_bit(p->prio, array->bitmap);
array->nr_active++;
p->array = array;
- class_enqueue_task(p,array);
}
/*
static int effective_prio(task_t *p)
{
int bonus, prio;
+ struct vx_info *vxi;
if (rt_task(p))
return p->prio;
prio = p->static_prio - bonus;
-#ifdef CONFIG_VSERVER_HARDCPU
- if (task_vx_flags(p, VXF_SCHED_PRIO, 0))
- prio += effective_vavavoom(p, MAX_USER_PRIO);
-#endif
+ if ((vxi = p->vx_info) &&
+ vx_info_flags(vxi, VXF_SCHED_PRIO, 0))
+ prio += vx_effective_vavavoom(vxi, MAX_USER_PRIO);
if (prio < MAX_RT_PRIO)
prio = MAX_RT_PRIO;
*/
static inline void __activate_task(task_t *p, runqueue_t *rq)
{
- enqueue_task(p, rq_active(p,rq));
+ enqueue_task(p, rq->active);
rq->nr_running++;
}
*/
static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
{
- enqueue_task_head(p, rq_active(p,rq));
+ enqueue_task_head(p, rq->active);
rq->nr_running++;
}
-static void recalc_task_prio(task_t *p, unsigned long long now)
+static int recalc_task_prio(task_t *p, unsigned long long now)
{
+ /* Caller must always ensure 'now >= p->timestamp' */
unsigned long long __sleep_time = now - p->timestamp;
unsigned long sleep_time;
- if (__sleep_time > NS_MAX_SLEEP_AVG)
- sleep_time = NS_MAX_SLEEP_AVG;
- else
- sleep_time = (unsigned long)__sleep_time;
+ if (unlikely(p->policy == SCHED_BATCH))
+ sleep_time = 0;
+ else {
+ if (__sleep_time > NS_MAX_SLEEP_AVG)
+ sleep_time = NS_MAX_SLEEP_AVG;
+ else
+ sleep_time = (unsigned long)__sleep_time;
+ }
if (likely(sleep_time > 0)) {
/*
sleep_time > INTERACTIVE_SLEEP(p)) {
p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG -
DEF_TIMESLICE);
- if (!HIGH_CREDIT(p))
- p->interactive_credit++;
} else {
/*
* The lower the sleep avg a task has the more
sleep_time *= (MAX_BONUS - CURRENT_BONUS(p)) ? : 1;
/*
- * Tasks with low interactive_credit are limited to
- * one timeslice worth of sleep avg bonus.
+ * Tasks waking from uninterruptible sleep are
+ * limited in their sleep_avg rise as they
+ * are likely to be waiting on I/O
*/
- if (LOW_CREDIT(p) &&
- sleep_time > JIFFIES_TO_NS(task_timeslice(p)))
- sleep_time = JIFFIES_TO_NS(task_timeslice(p));
-
- /*
- * Non high_credit tasks waking from uninterruptible
- * sleep are limited in their sleep_avg rise as they
- * are likely to be cpu hogs waiting on I/O
- */
- if (p->activated == -1 && !HIGH_CREDIT(p) && p->mm) {
+ if (p->activated == -1 && p->mm) {
if (p->sleep_avg >= INTERACTIVE_SLEEP(p))
sleep_time = 0;
else if (p->sleep_avg + sleep_time >=
*/
p->sleep_avg += sleep_time;
- if (p->sleep_avg > NS_MAX_SLEEP_AVG) {
+ if (p->sleep_avg > NS_MAX_SLEEP_AVG)
p->sleep_avg = NS_MAX_SLEEP_AVG;
- if (!HIGH_CREDIT(p))
- p->interactive_credit++;
- }
}
}
- p->prio = effective_prio(p);
+ return effective_prio(p);
}
/*
}
#endif
- recalc_task_prio(p, now);
+ if (!rt_task(p))
+ p->prio = recalc_task_prio(p, now);
/*
* This checks to make sure it's not an uninterruptible task
{
rq->nr_running--;
dequeue_task(p, p->array);
-
p->array = NULL;
}
-static void deactivate_task(struct task_struct *p, runqueue_t *rq)
+static inline
+void deactivate_task(struct task_struct *p, runqueue_t *rq)
{
- __deactivate_task(p, rq);
vx_deactivate_task(p);
+ __deactivate_task(p, rq);
+}
+
+
+#ifdef CONFIG_VSERVER_HARDCPU
+/*
+ * vx_hold_task - put a task on the hold queue
+ */
+static inline
+void vx_hold_task(struct vx_info *vxi,
+ struct task_struct *p, runqueue_t *rq)
+{
+ __deactivate_task(p, rq);
+ p->state |= TASK_ONHOLD;
+ /* a new one on hold */
+ vx_onhold_inc(vxi);
+ list_add_tail(&p->run_list, &rq->hold_queue);
+}
+
+/*
+ * vx_unhold_task - put a task back to the runqueue
+ */
+static inline
+void vx_unhold_task(struct vx_info *vxi,
+ struct task_struct *p, runqueue_t *rq)
+{
+ list_del(&p->run_list);
+ /* one less waiting */
+ vx_onhold_dec(vxi);
+ p->state &= ~TASK_ONHOLD;
+ enqueue_task(p, rq->expired);
+ rq->nr_running++;
+
+ if (p->static_prio < rq->best_expired_prio)
+ rq->best_expired_prio = p->static_prio;
+}
+#else
+static inline
+void vx_hold_task(struct vx_info *vxi,
+ struct task_struct *p, runqueue_t *rq)
+{
+ return;
+}
+
+static inline
+void vx_unhold_task(struct vx_info *vxi,
+ struct task_struct *p, runqueue_t *rq)
+{
+ return;
}
+#endif /* CONFIG_VSERVER_HARDCPU */
+
/*
* resched_task - mark a task 'to be rescheduled now'.
#ifdef CONFIG_SMP
static void resched_task(task_t *p)
{
- int need_resched, nrpolling;
+ int cpu;
+
+ assert_spin_locked(&task_rq(p)->lock);
- BUG_ON(!spin_is_locked(&task_rq(p)->lock));
+ if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+ return;
+
+ set_tsk_thread_flag(p, TIF_NEED_RESCHED);
- /* minimise the chance of sending an interrupt to poll_idle() */
- nrpolling = test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
- need_resched = test_and_set_tsk_thread_flag(p,TIF_NEED_RESCHED);
- nrpolling |= test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
+ cpu = task_cpu(p);
+ if (cpu == smp_processor_id())
+ return;
- if (!need_resched && !nrpolling && (task_cpu(p) != smp_processor_id()))
- smp_send_reschedule(task_cpu(p));
+ /* NEED_RESCHED must be visible before we test POLLING_NRFLAG */
+ smp_mb();
+ if (!test_tsk_thread_flag(p, TIF_POLLING_NRFLAG))
+ smp_send_reschedule(cpu);
}
#else
static inline void resched_task(task_t *p)
{
+ assert_spin_locked(&task_rq(p)->lock);
set_tsk_need_resched(p);
}
#endif
}
#ifdef CONFIG_SMP
-enum request_type {
- REQ_MOVE_TASK,
- REQ_SET_DOMAIN,
-};
-
typedef struct {
struct list_head list;
- enum request_type type;
- /* For REQ_MOVE_TASK */
task_t *task;
int dest_cpu;
- /* For REQ_SET_DOMAIN */
- struct sched_domain *sd;
-
struct completion done;
} migration_req_t;
}
init_completion(&req->done);
- req->type = REQ_MOVE_TASK;
req->task = p;
req->dest_cpu = dest_cpu;
list_add(&req->list, &rq->migration_queue);
* smp_call_function() if an IPI is sent by the same process we are
* waiting to become inactive.
*/
-void wait_task_inactive(task_t * p)
+void wait_task_inactive(task_t *p)
{
unsigned long flags;
runqueue_t *rq;
repeat:
rq = task_rq_lock(p, &flags);
/* Must be off runqueue entirely, not preempted. */
- if (unlikely(p->array)) {
+ if (unlikely(p->array || task_running(rq, p))) {
/* If it's preempted, we yield. It could be a while. */
preempted = !task_running(rq, p);
task_rq_unlock(rq, &flags);
*
* 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(task_t *p)
{
* We want to under-estimate the load of migration sources, to
* balance conservatively.
*/
-static inline unsigned long source_load(int cpu)
+static inline unsigned long source_load(int cpu, int type)
{
runqueue_t *rq = cpu_rq(cpu);
unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+ if (type == 0)
+ return load_now;
- return min(rq->cpu_load, load_now);
+ return min(rq->cpu_load[type-1], load_now);
}
/*
* Return a high guess at the load of a migration-target cpu
*/
-static inline unsigned long target_load(int cpu)
+static inline unsigned long target_load(int cpu, int type)
{
runqueue_t *rq = cpu_rq(cpu);
unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+ if (type == 0)
+ return load_now;
- return max(rq->cpu_load, load_now);
+ return max(rq->cpu_load[type-1], load_now);
}
-#endif
+/*
+ * 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))
+ goto nextgroup;
+
+ 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(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 = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
+
+ if (local_group) {
+ this_load = avg_load;
+ this = group;
+ } else if (avg_load < min_load) {
+ min_load = avg_load;
+ idlest = group;
+ }
+nextgroup:
+ group = group->next;
+ } while (group != sd->groups);
+
+ if (!idlest || 100*this_load < imbalance*min_load)
+ return NULL;
+ return idlest;
+}
/*
- * wake_idle() is useful especially on SMT architectures to wake a
- * task onto an idle sibling if we would otherwise wake it onto a
- * busy sibling.
- *
- * Returns the CPU we should wake onto.
+ * find_idlest_queue - find the idlest runqueue among the cpus in group.
*/
-#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
-static int wake_idle(int cpu, task_t *p)
+static int
+find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
{
cpumask_t tmp;
- runqueue_t *rq = cpu_rq(cpu);
- struct sched_domain *sd;
+ unsigned long load, min_load = ULONG_MAX;
+ int idlest = -1;
int i;
- if (idle_cpu(cpu))
- return cpu;
-
- sd = rq->sd;
- if (!(sd->flags & SD_WAKE_IDLE))
- return cpu;
-
- cpus_and(tmp, sd->span, p->cpus_allowed);
+ /* Traverse only the allowed CPUs */
+ cpus_and(tmp, group->cpumask, p->cpus_allowed);
for_each_cpu_mask(i, tmp) {
- if (idle_cpu(i))
- return i;
+ load = source_load(i, 0);
+
+ if (load < min_load || (load == min_load && i == this_cpu)) {
+ min_load = load;
+ idlest = i;
+ }
}
- return cpu;
-}
-#else
-static inline int wake_idle(int cpu, task_t *p)
-{
- return cpu;
+ return idlest;
}
-#endif
-/***
- * 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?
+/*
+ * 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.
*
- * 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.
+ * Balance, ie. select the least loaded group.
*
- * returns failure only if the task is already active.
+ * Returns the target CPU number, or the same CPU if no balancing is needed.
+ *
+ * preempt must be disabled.
*/
-static int try_to_wake_up(task_t * p, unsigned int state, int sync)
+static int sched_balance_self(int cpu, int flag)
{
- int cpu, this_cpu, success = 0;
- unsigned long flags;
+ struct task_struct *t = current;
+ struct sched_domain *tmp, *sd = NULL;
+
+ for_each_domain(cpu, tmp)
+ if (tmp->flags & flag)
+ sd = tmp;
+
+ while (sd) {
+ cpumask_t span;
+ struct sched_group *group;
+ int new_cpu;
+ int weight;
+
+ span = sd->span;
+ group = find_idlest_group(sd, t, cpu);
+ if (!group)
+ goto nextlevel;
+
+ new_cpu = find_idlest_cpu(group, t, cpu);
+ if (new_cpu == -1 || new_cpu == cpu)
+ goto nextlevel;
+
+ /* Now try balancing at a lower domain level */
+ cpu = new_cpu;
+nextlevel:
+ 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 */
+
+/*
+ * wake_idle() will wake a task on an idle cpu if task->cpu is
+ * not idle and an idle cpu is available. The span of cpus to
+ * search starts with cpus closest then further out as needed,
+ * so we always favor a closer, idle cpu.
+ *
+ * Returns the CPU we should wake onto.
+ */
+#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
+static int wake_idle(int cpu, task_t *p)
+{
+ cpumask_t tmp;
+ struct sched_domain *sd;
+ int i;
+
+ if (idle_cpu(cpu))
+ return cpu;
+
+ for_each_domain(cpu, sd) {
+ if (sd->flags & SD_WAKE_IDLE) {
+ cpus_and(tmp, sd->span, p->cpus_allowed);
+ for_each_cpu_mask(i, tmp) {
+ if (idle_cpu(i))
+ return i;
+ }
+ }
+ else
+ break;
+ }
+ return cpu;
+}
+#else
+static inline int wake_idle(int cpu, task_t *p)
+{
+ return cpu;
+}
+#endif
+
+/***
+ * 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(task_t *p, unsigned int state, int sync)
+{
+ int cpu, this_cpu, success = 0;
+ unsigned long flags;
long old_state;
runqueue_t *rq;
#ifdef CONFIG_SMP
unsigned long load, this_load;
- struct sched_domain *sd;
+ struct sched_domain *sd, *this_sd = NULL;
int new_cpu;
#endif
rq = task_rq_lock(p, &flags);
- schedstat_inc(rq, ttwu_cnt);
old_state = p->state;
+
+ /* we need to unhold suspended tasks */
+ if (old_state & TASK_ONHOLD) {
+ vx_unhold_task(p->vx_info, p, rq);
+ old_state = p->state;
+ }
if (!(old_state & state))
goto out;
new_cpu = cpu;
- if (cpu == this_cpu || unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
+ schedstat_inc(rq, ttwu_cnt);
+ if (cpu == this_cpu) {
+ schedstat_inc(rq, ttwu_local);
goto out_set_cpu;
+ }
- load = source_load(cpu);
- this_load = target_load(this_cpu);
-
- /*
- * If sync wakeup then subtract the (maximum possible) effect of
- * the currently running task from the load of the current CPU:
- */
- if (sync)
- this_load -= SCHED_LOAD_SCALE;
+ for_each_domain(this_cpu, sd) {
+ if (cpu_isset(cpu, sd->span)) {
+ schedstat_inc(sd, ttwu_wake_remote);
+ this_sd = sd;
+ break;
+ }
+ }
- /* Don't pull the task off an idle CPU to a busy one */
- if (load < SCHED_LOAD_SCALE/2 && this_load > SCHED_LOAD_SCALE/2)
+ if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
goto out_set_cpu;
- new_cpu = this_cpu; /* Wake to this CPU if we can */
-
/*
- * Scan domains for affine wakeup and passive balancing
- * possibilities.
+ * Check for affine wakeup and passive balancing possibilities.
*/
- for_each_domain(this_cpu, sd) {
+ if (this_sd) {
+ int idx = this_sd->wake_idx;
unsigned int imbalance;
- /*
- * Start passive balancing when half the imbalance_pct
- * limit is reached.
- */
- imbalance = sd->imbalance_pct + (sd->imbalance_pct - 100) / 2;
- if ((sd->flags & SD_WAKE_AFFINE) &&
- !task_hot(p, rq->timestamp_last_tick, sd)) {
+ imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
+
+ load = source_load(cpu, idx);
+ this_load = target_load(this_cpu, idx);
+
+ new_cpu = this_cpu; /* Wake to this CPU if we can */
+
+ if (this_sd->flags & SD_WAKE_AFFINE) {
+ unsigned long tl = this_load;
/*
- * This domain has SD_WAKE_AFFINE and p is cache cold
- * in this domain.
+ * If sync wakeup then subtract the (maximum possible)
+ * effect of the currently running task from the load
+ * of the current CPU:
*/
- if (cpu_isset(cpu, sd->span)) {
- schedstat_inc(sd, ttwu_wake_affine);
+ if (sync)
+ tl -= SCHED_LOAD_SCALE;
+
+ if ((tl <= load &&
+ tl + target_load(cpu, idx) <= SCHED_LOAD_SCALE) ||
+ 100*(tl + SCHED_LOAD_SCALE) <= imbalance*load) {
+ /*
+ * This domain has SD_WAKE_AFFINE and
+ * p is cache cold in this domain, and
+ * there is no bad imbalance.
+ */
+ schedstat_inc(this_sd, ttwu_move_affine);
goto out_set_cpu;
}
- } else if ((sd->flags & SD_WAKE_BALANCE) &&
- imbalance*this_load <= 100*load) {
- /*
- * This domain has SD_WAKE_BALANCE and there is
- * an imbalance.
- */
- if (cpu_isset(cpu, sd->span)) {
- schedstat_inc(sd, ttwu_wake_balance);
+ }
+
+ /*
+ * Start passive balancing when half the imbalance_pct
+ * limit is reached.
+ */
+ if (this_sd->flags & SD_WAKE_BALANCE) {
+ if (imbalance*this_load <= 100*load) {
+ schedstat_inc(this_sd, ttwu_move_balance);
goto out_set_cpu;
}
}
new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
out_set_cpu:
- schedstat_inc(rq, ttwu_attempts);
new_cpu = wake_idle(new_cpu, p);
- if (new_cpu != cpu && cpu_isset(new_cpu, p->cpus_allowed)) {
- schedstat_inc(rq, ttwu_moved);
+ if (new_cpu != cpu) {
set_task_cpu(p, new_cpu);
task_rq_unlock(rq, &flags);
/* might preempt at this point */
p->activated = -1;
}
+ /*
+ * Tasks that have marked their sleep as noninteractive get
+ * woken up without updating their sleep average. (i.e. their
+ * sleep is handled in a priority-neutral manner, no priority
+ * boost and no penalty.)
+ */
+ if (old_state & TASK_NONINTERACTIVE) {
+ vx_activate_task(p);
+ __activate_task(p, rq);
+ } else
+ activate_task(p, rq, cpu == this_cpu);
+
+ /* this is to get the accounting behind the load update */
+ if (old_state & TASK_UNINTERRUPTIBLE)
+ vx_uninterruptible_dec(p);
+
/*
* Sync wakeups (i.e. those types of wakeups where the waker
* has indicated that it will leave the CPU in short order)
* the waker guarantees that the freshly woken up task is going
* to be considered on this CPU.)
*/
- activate_task(p, rq, cpu == this_cpu);
if (!sync || cpu != this_cpu) {
if (TASK_PREEMPTS_CURR(p, rq))
resched_task(rq->curr);
return success;
}
-int fastcall wake_up_process(task_t * p)
+int fastcall wake_up_process(task_t *p)
{
return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED |
- TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0);
+ TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0);
}
EXPORT_SYMBOL(wake_up_process);
return try_to_wake_up(p, state, 0);
}
-#ifdef CONFIG_SMP
-static int find_idlest_cpu(struct task_struct *p, int this_cpu,
- struct sched_domain *sd);
-#endif
-
/*
* Perform scheduler related setup for a newly forked process p.
* p is forked by current.
*/
-void fastcall sched_fork(task_t *p)
+void fastcall sched_fork(task_t *p, int clone_flags)
{
+ int cpu = get_cpu();
+
+#ifdef CONFIG_SMP
+ cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
+#endif
+ set_task_cpu(p, cpu);
+
/*
* We mark the process as running here, but have not actually
* inserted it onto the runqueue yet. This guarantees that
p->state = TASK_RUNNING;
INIT_LIST_HEAD(&p->run_list);
p->array = NULL;
- spin_lock_init(&p->switch_lock);
#ifdef CONFIG_SCHEDSTATS
memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- cpu_demand_event(&p->demand_stat,CPU_DEMAND_INIT,0);
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
+ p->oncpu = 0;
#endif
#ifdef CONFIG_PREEMPT
- /*
- * During context-switch we hold precisely one spinlock, which
- * schedule_tail drops. (in the common case it's this_rq()->lock,
- * but it also can be p->switch_lock.) So we compensate with a count
- * of 1. Also, we want to start with kernel preemption disabled.
- */
- p->thread_info->preempt_count = 1;
+ /* Want to start with kernel preemption disabled. */
+ task_thread_info(p)->preempt_count = 1;
#endif
/*
* Share the timeslice between parent and child, thus the
* runqueue lock is not a problem.
*/
current->time_slice = 1;
- preempt_disable();
- scheduler_tick(0, 0);
- local_irq_enable();
- preempt_enable();
- } else
- local_irq_enable();
+ scheduler_tick();
+ }
+ local_irq_enable();
+ put_cpu();
}
/*
* that must be done for every newly created context, then puts the task
* on the runqueue and wakes it.
*/
-void fastcall wake_up_new_task(task_t * p, unsigned long clone_flags)
+void fastcall wake_up_new_task(task_t *p, unsigned long clone_flags)
{
unsigned long flags;
int this_cpu, cpu;
runqueue_t *rq, *this_rq;
rq = task_rq_lock(p, &flags);
- cpu = task_cpu(p);
- this_cpu = smp_processor_id();
-
BUG_ON(p->state != TASK_RUNNING);
+ this_cpu = smp_processor_id();
+ cpu = task_cpu(p);
- schedstat_inc(rq, wunt_cnt);
/*
* We decrease the sleep average of forking parents
* and children as well, to keep max-interactive tasks
p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) *
CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
- p->interactive_credit = 0;
-
p->prio = effective_prio(p);
vx_activate_task(p);
__activate_task(p, rq);
else {
p->prio = current->prio;
+ BUG_ON(p->state & TASK_ONHOLD);
list_add_tail(&p->run_list, ¤t->run_list);
p->array = current->array;
p->array->nr_active++;
rq->nr_running++;
- class_enqueue_task(p,p->array);
}
set_need_resched();
} else
if (TASK_PREEMPTS_CURR(p, rq))
resched_task(rq->curr);
- schedstat_inc(rq, wunt_moved);
/*
* Parent and child are on different CPUs, now get the
* parent runqueue to update the parent's ->sleep_avg:
* artificially, because any timeslice recovered here
* was given away by the parent in the first place.)
*/
-void fastcall sched_exit(task_t * p)
+void fastcall sched_exit(task_t *p)
{
unsigned long flags;
runqueue_t *rq;
* the sleep_avg of the parent as well.
*/
rq = task_rq_lock(p->parent, &flags);
- if (p->first_time_slice) {
+ if (p->first_time_slice && task_cpu(p) == task_cpu(p->parent)) {
p->parent->time_slice += p->time_slice;
if (unlikely(p->parent->time_slice > task_timeslice(p)))
p->parent->time_slice = task_timeslice(p);
task_rq_unlock(rq, &flags);
}
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @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(runqueue_t *rq, task_t *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.
*
- * We enter this with the runqueue still locked, and finish_arch_switch()
- * will unlock it along with doing any other architecture-specific cleanup
- * actions.
+ * 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(task_t *prev)
+static inline void finish_task_switch(runqueue_t *rq, task_t *prev)
__releases(rq->lock)
{
- runqueue_t *rq = this_rq();
struct mm_struct *mm = rq->prev_mm;
unsigned long prev_task_flags;
* Manfred Spraul <manfred@colorfullife.com>
*/
prev_task_flags = prev->flags;
- finish_arch_switch(rq, prev);
+ finish_arch_switch(prev);
+ finish_lock_switch(rq, prev);
if (mm)
mmdrop(mm);
if (unlikely(prev_task_flags & PF_DEAD))
asmlinkage void schedule_tail(task_t *prev)
__releases(rq->lock)
{
- finish_task_switch(prev);
-
+ runqueue_t *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(current->pid, current->set_child_tid);
}
/*
* double_rq_lock - safely lock two runqueues
*
+ * We must take them in cpu order to match code in
+ * dependent_sleeper and wake_dependent_sleeper.
+ *
* Note this does not disable interrupts like task_rq_lock,
* you need to do so manually before calling.
*/
spin_lock(&rq1->lock);
__acquire(rq2->lock); /* Fake it out ;) */
} else {
- if (rq1 < rq2) {
+ if (rq1->cpu < rq2->cpu) {
spin_lock(&rq1->lock);
spin_lock(&rq2->lock);
} else {
__acquires(this_rq->lock)
{
if (unlikely(!spin_trylock(&busiest->lock))) {
- if (busiest < this_rq) {
+ if (busiest->cpu < this_rq->cpu) {
spin_unlock(&this_rq->lock);
spin_lock(&busiest->lock);
spin_lock(&this_rq->lock);
}
}
-/*
- * find_idlest_cpu - find the least busy runqueue.
- */
-static int find_idlest_cpu(struct task_struct *p, int this_cpu,
- struct sched_domain *sd)
-{
- unsigned long load, min_load, this_load;
- int i, min_cpu;
- cpumask_t mask;
-
- min_cpu = UINT_MAX;
- min_load = ULONG_MAX;
-
- cpus_and(mask, sd->span, p->cpus_allowed);
-
- for_each_cpu_mask(i, mask) {
- load = target_load(i);
-
- if (load < min_load) {
- min_cpu = i;
- min_load = load;
-
- /* break out early on an idle CPU: */
- if (!min_load)
- break;
- }
- }
-
- /* add +1 to account for the new task */
- this_load = source_load(this_cpu) + SCHED_LOAD_SCALE;
-
- /*
- * Would with the addition of the new task to the
- * current CPU there be an imbalance between this
- * CPU and the idlest CPU?
- *
- * Use half of the balancing threshold - new-context is
- * a good opportunity to balance.
- */
- if (min_load*(100 + (sd->imbalance_pct-100)/2) < this_load*100)
- return min_cpu;
-
- return this_cpu;
-}
-
/*
* If dest_cpu is allowed for this process, migrate the task to it.
* This is accomplished by forcing the cpu_allowed mask to only
|| unlikely(cpu_is_offline(dest_cpu)))
goto out;
- schedstat_inc(rq, smt_cnt);
/* force the process onto the specified CPU */
if (migrate_task(p, dest_cpu, &req)) {
/* Need to wait for migration thread (might exit: take ref). */
}
/*
- * sched_exec(): find the highest-level, exec-balance-capable
- * domain and try to migrate the task to the least loaded CPU.
- *
- * execve() is a valuable balancing opportunity, because at this point
- * the task has the smallest effective memory and cache footprint.
+ * 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)
{
- struct sched_domain *tmp, *sd = NULL;
int new_cpu, this_cpu = get_cpu();
-
- schedstat_inc(this_rq(), sbe_cnt);
- /* Prefer the current CPU if there's only this task running */
- if (this_rq()->nr_running <= 1)
- goto out;
-
- for_each_domain(this_cpu, tmp)
- if (tmp->flags & SD_BALANCE_EXEC)
- sd = tmp;
-
- if (sd) {
- schedstat_inc(sd, sbe_attempts);
- new_cpu = find_idlest_cpu(current, this_cpu, sd);
- if (new_cpu != this_cpu) {
- schedstat_inc(sd, sbe_pushed);
- put_cpu();
- sched_migrate_task(current, new_cpu);
- return;
- }
- }
-out:
+ 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 inline
+static
void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p,
runqueue_t *this_rq, prio_array_t *this_array, int this_cpu)
{
/*
* can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
*/
-static inline
+static
int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu,
- struct sched_domain *sd, enum idle_type idle)
+ struct sched_domain *sd, enum idle_type idle,
+ int *all_pinned)
{
/*
* We do not migrate tasks that are:
* 2) cannot be migrated to this CPU due to cpus_allowed, or
* 3) are cache-hot on their current CPU.
*/
- if (task_running(rq, p))
- return 0;
if (!cpu_isset(this_cpu, p->cpus_allowed))
return 0;
+ *all_pinned = 0;
- /* Aggressive migration if we've failed balancing */
- if (idle == NEWLY_IDLE ||
- sd->nr_balance_failed < sd->cache_nice_tries) {
- if (task_hot(p, rq->timestamp_last_tick, sd))
- return 0;
- }
+ if (task_running(rq, p))
+ return 0;
- return 1;
-}
+ /*
+ * Aggressive migration if:
+ * 1) task is cache cold, or
+ * 2) too many balance attempts have failed.
+ */
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
-static inline int ckrm_preferred_task(task_t *tmp,long min, long max,
- int phase, enum idle_type idle)
-{
- long pressure = task_load(tmp);
-
- if (pressure > max)
- return 0;
+ if (sd->nr_balance_failed > sd->cache_nice_tries)
+ return 1;
- if ((idle == NOT_IDLE) && ! phase && (pressure <= min))
+ if (task_hot(p, rq->timestamp_last_tick, sd))
return 0;
return 1;
}
/*
- * move tasks for a specic local class
- * return number of tasks pulled
+ * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq,
+ * as part of a balancing operation within "domain". Returns the number of
+ * tasks moved.
+ *
+ * Called with both runqueues locked.
*/
-static inline int ckrm_cls_move_tasks(ckrm_lrq_t* src_lrq,ckrm_lrq_t*dst_lrq,
- runqueue_t *this_rq,
- runqueue_t *busiest,
- struct sched_domain *sd,
- int this_cpu,
- enum idle_type idle,
- long* pressure_imbalance)
+static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
+ unsigned long max_nr_move, struct sched_domain *sd,
+ enum idle_type idle, int *all_pinned)
{
prio_array_t *array, *dst_array;
struct list_head *head, *curr;
+ int idx, pulled = 0, pinned = 0;
task_t *tmp;
- int idx;
- int pulled = 0;
- int phase = -1;
- long pressure_min, pressure_max;
- /*hzheng: magic : 90% balance is enough*/
- long balance_min = *pressure_imbalance / 10;
-/*
- * we don't want to migrate tasks that will reverse the balance
- * or the tasks that make too small difference
- */
-#define CKRM_BALANCE_MAX_RATIO 100
-#define CKRM_BALANCE_MIN_RATIO 1
- start:
- phase ++;
+
+ if (max_nr_move == 0)
+ goto out;
+
+ pinned = 1;
+
/*
* We first consider expired tasks. Those will likely not be
* executed in the near future, and they are most likely to
* be cache-cold, thus switching CPUs has the least effect
* on them.
*/
- if (src_lrq->expired->nr_active) {
- array = src_lrq->expired;
- dst_array = dst_lrq->expired;
+ if (busiest->expired->nr_active) {
+ array = busiest->expired;
+ dst_array = this_rq->expired;
} else {
- array = src_lrq->active;
- dst_array = dst_lrq->active;
+ array = busiest->active;
+ dst_array = this_rq->active;
}
-
- new_array:
+
+new_array:
/* Start searching at priority 0: */
idx = 0;
- skip_bitmap:
+skip_bitmap:
if (!idx)
idx = sched_find_first_bit(array->bitmap);
else
idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
if (idx >= MAX_PRIO) {
- if (array == src_lrq->expired && src_lrq->active->nr_active) {
- array = src_lrq->active;
- dst_array = dst_lrq->active;
+ if (array == busiest->expired && busiest->active->nr_active) {
+ array = busiest->active;
+ dst_array = this_rq->active;
goto new_array;
}
- if ((! phase) && (! pulled) && (idle != IDLE))
- goto start; //try again
- else
- goto out; //finished search for this lrq
+ goto out;
}
-
+
head = array->queue + idx;
curr = head->prev;
- skip_queue:
+skip_queue:
tmp = list_entry(curr, task_t, run_list);
-
+
curr = curr->prev;
-
- if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle)) {
+
+ if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) {
if (curr != head)
goto skip_queue;
idx++;
goto skip_bitmap;
}
- pressure_min = *pressure_imbalance * CKRM_BALANCE_MIN_RATIO/100;
- pressure_max = *pressure_imbalance * CKRM_BALANCE_MAX_RATIO/100;
- /*
- * skip the tasks that will reverse the balance too much
- */
- if (ckrm_preferred_task(tmp,pressure_min,pressure_max,phase,idle)) {
- *pressure_imbalance -= task_load(tmp);
- pull_task(busiest, array, tmp,
- this_rq, dst_array, this_cpu);
- pulled++;
+#ifdef CONFIG_SCHEDSTATS
+ if (task_hot(tmp, busiest->timestamp_last_tick, sd))
+ schedstat_inc(sd, lb_hot_gained[idle]);
+#endif
- if (*pressure_imbalance <= balance_min)
- goto out;
- }
-
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
- out:
- return pulled;
-}
+ pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
+ pulled++;
-static inline long ckrm_rq_imbalance(runqueue_t *this_rq,runqueue_t *dst_rq)
-{
- long imbalance;
+ /* We only want to steal up to the prescribed number of tasks. */
+ if (pulled < max_nr_move) {
+ if (curr != head)
+ goto skip_queue;
+ idx++;
+ goto skip_bitmap;
+ }
+out:
/*
- * make sure after balance, imbalance' > - imbalance/2
- * we don't want the imbalance be reversed too much
+ * Right now, this is the only place pull_task() is called,
+ * so we can safely collect pull_task() stats here rather than
+ * inside pull_task().
*/
- imbalance = pid_get_pressure(rq_ckrm_load(dst_rq),0)
- - pid_get_pressure(rq_ckrm_load(this_rq),1);
- imbalance /= 2;
- return imbalance;
+ schedstat_add(sd, lb_gained[idle], pulled);
+
+ if (all_pinned)
+ *all_pinned = pinned;
+ return pulled;
}
/*
- * try to balance the two runqueues
- *
- * Called with both runqueues locked.
- * if move_tasks is called, it will try to move at least one task over
+ * find_busiest_group finds and returns the busiest CPU group within the
+ * domain. It calculates and returns the number of tasks which should be
+ * moved to restore balance via the imbalance parameter.
*/
-static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
- unsigned long max_nr_move, struct sched_domain *sd,
- enum idle_type idle)
+static struct sched_group *
+find_busiest_group(struct sched_domain *sd, int this_cpu,
+ unsigned long *imbalance, enum idle_type idle, int *sd_idle,
+ cpumask_t *cpus)
{
- struct ckrm_cpu_class *clsptr,*vip_cls = NULL;
- ckrm_lrq_t* src_lrq,*dst_lrq;
- long pressure_imbalance, pressure_imbalance_old;
- int src_cpu = task_cpu(busiest->curr);
- struct list_head *list;
- int pulled = 0;
- long imbalance;
-
- imbalance = ckrm_rq_imbalance(this_rq,busiest);
+ 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;
+ int load_idx;
- if ((idle == NOT_IDLE && imbalance <= 0) || busiest->nr_running <= 1)
- goto out;
+ max_load = this_load = total_load = total_pwr = 0;
+ if (idle == NOT_IDLE)
+ load_idx = sd->busy_idx;
+ else if (idle == NEWLY_IDLE)
+ load_idx = sd->newidle_idx;
+ else
+ load_idx = sd->idle_idx;
- //try to find the vip class
- list_for_each_entry(clsptr,&active_cpu_classes,links) {
- src_lrq = get_ckrm_lrq(clsptr,src_cpu);
+ do {
+ unsigned long load;
+ int local_group;
+ int i;
- if (! lrq_nr_running(src_lrq))
- continue;
+ local_group = cpu_isset(this_cpu, group->cpumask);
- if (! vip_cls || cpu_class_weight(vip_cls) < cpu_class_weight(clsptr) )
- {
- vip_cls = clsptr;
- }
- }
+ /* Tally up the load of all CPUs in the group */
+ avg_load = 0;
- /*
- * do search from the most significant class
- * hopefully, less tasks will be migrated this way
- */
- clsptr = vip_cls;
-
- move_class:
- if (! clsptr)
- goto out;
-
-
- src_lrq = get_ckrm_lrq(clsptr,src_cpu);
- if (! lrq_nr_running(src_lrq))
- goto other_class;
-
- dst_lrq = get_ckrm_lrq(clsptr,this_cpu);
-
- //how much pressure for this class should be transferred
- pressure_imbalance = src_lrq->lrq_load * imbalance/src_lrq->local_weight;
- if (pulled && ! pressure_imbalance)
- goto other_class;
-
- pressure_imbalance_old = pressure_imbalance;
-
- //move tasks
- pulled +=
- ckrm_cls_move_tasks(src_lrq,dst_lrq,
- this_rq,
- busiest,
- sd,this_cpu,idle,
- &pressure_imbalance);
-
- /*
- * hzheng: 2 is another magic number
- * stop balancing if the imbalance is less than 25% of the orig
- */
- if (pressure_imbalance <= (pressure_imbalance_old >> 2))
- goto out;
-
- //update imbalance
- imbalance *= pressure_imbalance / pressure_imbalance_old;
- other_class:
- //who is next?
- list = clsptr->links.next;
- if (list == &active_cpu_classes)
- list = list->next;
- clsptr = list_entry(list, typeof(*clsptr), links);
- if (clsptr != vip_cls)
- goto move_class;
- out:
- return pulled;
-}
-
-/**
- * ckrm_check_balance - is load balancing necessary?
- * return 0 if load balancing is not necessary
- * otherwise return the average load of the system
- * also, update nr_group
- *
- * heuristics:
- * no load balancing if it's load is over average
- * no load balancing if it's load is far more than the min
- * task:
- * read the status of all the runqueues
- */
-static unsigned long ckrm_check_balance(struct sched_domain *sd, int this_cpu,
- enum idle_type idle, int* nr_group)
-{
- struct sched_group *group = sd->groups;
- unsigned long min_load, max_load, avg_load;
- unsigned long total_load, this_load, total_pwr;
-
- max_load = this_load = total_load = total_pwr = 0;
- min_load = 0xFFFFFFFF;
- *nr_group = 0;
-
- do {
- cpumask_t tmp;
- unsigned long load;
- int local_group;
- int i, nr_cpus = 0;
-
- /* Tally up the load of all CPUs in the group */
- cpus_and(tmp, group->cpumask, cpu_online_map);
- if (unlikely(cpus_empty(tmp)))
- goto nextgroup;
-
- avg_load = 0;
- local_group = cpu_isset(this_cpu, group->cpumask);
-
- for_each_cpu_mask(i, tmp) {
- load = pid_get_pressure(rq_ckrm_load(cpu_rq(i)),local_group);
- nr_cpus++;
- avg_load += load;
- }
-
- if (!nr_cpus)
- goto nextgroup;
-
- total_load += avg_load;
- total_pwr += group->cpu_power;
-
- /* Adjust by relative CPU power of the group */
- avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
-
- if (local_group) {
- this_load = avg_load;
- goto nextgroup;
- } else if (avg_load > max_load) {
- max_load = avg_load;
- }
- if (avg_load < min_load) {
- min_load = avg_load;
- }
-nextgroup:
- group = group->next;
- *nr_group = *nr_group + 1;
- } while (group != sd->groups);
-
- if (!max_load || this_load >= max_load)
- goto out_balanced;
-
- avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
-
- /* hzheng: debugging: 105 is a magic number
- * 100*max_load <= sd->imbalance_pct*this_load)
- * should use imbalance_pct instead
- */
- if (this_load > avg_load
- || 100*max_load < 105*this_load
- || 100*min_load < 70*this_load
- )
- goto out_balanced;
-
- return avg_load;
- out_balanced:
- return 0;
-}
-
-/**
- * any group that has above average load is considered busy
- * find the busiest queue from any of busy group
- */
-static runqueue_t *
-ckrm_find_busy_queue(struct sched_domain *sd, int this_cpu,
- unsigned long avg_load, enum idle_type idle,
- int nr_group)
-{
- struct sched_group *group;
- runqueue_t * busiest=NULL;
- unsigned long rand;
-
- group = sd->groups;
- rand = get_ckrm_rand(nr_group);
- nr_group = 0;
-
- do {
- unsigned long load,total_load,max_load;
- cpumask_t tmp;
- int i;
- runqueue_t * grp_busiest;
-
- cpus_and(tmp, group->cpumask, cpu_online_map);
- if (unlikely(cpus_empty(tmp)))
- goto find_nextgroup;
-
- total_load = 0;
- max_load = 0;
- grp_busiest = NULL;
- for_each_cpu_mask(i, tmp) {
- load = pid_get_pressure(rq_ckrm_load(cpu_rq(i)),0);
- total_load += load;
- if (load > max_load) {
- max_load = load;
- grp_busiest = cpu_rq(i);
- }
- }
-
- total_load = (total_load * SCHED_LOAD_SCALE) / group->cpu_power;
- if (total_load > avg_load) {
- busiest = grp_busiest;
- if (nr_group >= rand)
- break;
- }
- find_nextgroup:
- group = group->next;
- nr_group ++;
- } while (group != sd->groups);
-
- return busiest;
-}
-
-/**
- * load_balance - pressure based load balancing algorithm used by ckrm
- */
-static int ckrm_load_balance(int this_cpu, runqueue_t *this_rq,
- struct sched_domain *sd, enum idle_type idle)
-{
- runqueue_t *busiest;
- unsigned long avg_load;
- int nr_moved,nr_group;
-
- avg_load = ckrm_check_balance(sd, this_cpu, idle, &nr_group);
- if (! avg_load)
- goto out_balanced;
-
- busiest = ckrm_find_busy_queue(sd,this_cpu,avg_load,idle,nr_group);
- if (! busiest)
- goto out_balanced;
- /*
- * This should be "impossible", but since load
- * balancing is inherently racy and statistical,
- * it could happen in theory.
- */
- if (unlikely(busiest == this_rq)) {
- WARN_ON(1);
- goto out_balanced;
- }
-
- nr_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. nr_moved simply stays zero, so it is
- * correctly treated as an imbalance.
- */
- double_lock_balance(this_rq, busiest);
- nr_moved = move_tasks(this_rq, this_cpu, busiest,
- 0,sd, idle);
- spin_unlock(&busiest->lock);
- if (nr_moved) {
- adjust_local_weight();
- }
- }
-
- if (!nr_moved)
- sd->nr_balance_failed ++;
- else
- sd->nr_balance_failed = 0;
-
- /* We were unbalanced, so reset the balancing interval */
- sd->balance_interval = sd->min_interval;
-
- return nr_moved;
-
-out_balanced:
- /* tune up the balancing interval */
- if (sd->balance_interval < sd->max_interval)
- sd->balance_interval *= 2;
-
- return 0;
-}
-
-/*
- * this_rq->lock is already held
- */
-static inline int load_balance_newidle(int this_cpu, runqueue_t *this_rq,
- struct sched_domain *sd)
-{
- int ret;
- read_lock(&class_list_lock);
- ret = ckrm_load_balance(this_cpu,this_rq,sd,NEWLY_IDLE);
- read_unlock(&class_list_lock);
- return ret;
-}
-
-static inline int load_balance(int this_cpu, runqueue_t *this_rq,
- struct sched_domain *sd, enum idle_type idle)
-{
- int ret;
-
- spin_lock(&this_rq->lock);
- read_lock(&class_list_lock);
- ret= ckrm_load_balance(this_cpu,this_rq,sd,NEWLY_IDLE);
- read_unlock(&class_list_lock);
- spin_unlock(&this_rq->lock);
- return ret;
-}
-#else /*! CONFIG_CKRM_CPU_SCHEDULE */
-/*
- * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq,
- * as part of a balancing operation within "domain". Returns the number of
- * tasks moved.
- *
- * Called with both runqueues locked.
- */
-static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
- unsigned long max_nr_move, struct sched_domain *sd,
- enum idle_type idle)
-{
- prio_array_t *array, *dst_array;
- struct list_head *head, *curr;
- int idx, pulled = 0;
- task_t *tmp;
-
- if (max_nr_move <= 0 || busiest->nr_running <= 1)
- goto out;
-
- /*
- * We first consider expired tasks. Those will likely not be
- * executed in the near future, and they are most likely to
- * be cache-cold, thus switching CPUs has the least effect
- * on them.
- */
- if (busiest->expired->nr_active) {
- array = busiest->expired;
- dst_array = this_rq->expired;
- } else {
- array = busiest->active;
- dst_array = this_rq->active;
- }
-
-new_array:
- /* Start searching at priority 0: */
- idx = 0;
-skip_bitmap:
- if (!idx)
- idx = sched_find_first_bit(array->bitmap);
- else
- idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
- if (idx >= MAX_PRIO) {
- if (array == busiest->expired && busiest->active->nr_active) {
- array = busiest->active;
- dst_array = this_rq->active;
- goto new_array;
- }
- goto out;
- }
-
- head = array->queue + idx;
- curr = head->prev;
-skip_queue:
- tmp = list_entry(curr, task_t, run_list);
-
- curr = curr->prev;
-
- if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle)) {
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
- }
-
- /*
- * Right now, this is the only place pull_task() is called,
- * so we can safely collect pull_task() stats here rather than
- * inside pull_task().
- */
- schedstat_inc(this_rq, pt_gained[idle]);
- schedstat_inc(busiest, pt_lost[idle]);
-
- pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
- pulled++;
-
- /* We only want to steal up to the prescribed number of tasks. */
- if (pulled < max_nr_move) {
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
- }
-out:
- return pulled;
-}
-
-/*
- * find_busiest_group finds and returns the busiest CPU group within the
- * domain. It calculates and returns the number of tasks 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 idle_type idle)
-{
- struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
- unsigned long max_load, avg_load, total_load, this_load, total_pwr;
-
- max_load = this_load = total_load = total_pwr = 0;
-
- do {
- unsigned long load;
- int local_group;
- int i, nr_cpus = 0;
-
- local_group = cpu_isset(this_cpu, group->cpumask);
+ for_each_cpu_mask(i, group->cpumask) {
+ if (!cpu_isset(i, *cpus))
+ continue;
- /* Tally up the load of all CPUs in the group */
- avg_load = 0;
+ if (*sd_idle && !idle_cpu(i))
+ *sd_idle = 0;
- for_each_cpu_mask(i, group->cpumask) {
/* Bias balancing toward cpus of our domain */
if (local_group)
- load = target_load(i);
+ load = target_load(i, load_idx);
else
- load = source_load(i);
+ load = source_load(i, load_idx);
- nr_cpus++;
avg_load += load;
}
- if (!nr_cpus)
- goto nextgroup;
-
total_load += avg_load;
total_pwr += group->cpu_power;
if (local_group) {
this_load = avg_load;
this = group;
- goto nextgroup;
} else if (avg_load > max_load) {
max_load = avg_load;
busiest = group;
}
-nextgroup:
group = group->next;
} while (group != sd->groups);
- if (!busiest || this_load >= max_load)
+ if (!busiest || this_load >= max_load || max_load <= SCHED_LOAD_SCALE)
goto out_balanced;
avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
* by pulling tasks to us. Be careful of negative numbers as they'll
* appear as very large values with unsigned longs.
*/
- *imbalance = min(max_load - avg_load, avg_load - this_load);
+
+ /* Don't want to pull so many tasks that a group would go idle */
+ max_pull = min(max_load - avg_load, max_load - SCHED_LOAD_SCALE);
/* How much load to actually move to equalise the imbalance */
- *imbalance = (*imbalance * min(busiest->cpu_power, this->cpu_power))
- / SCHED_LOAD_SCALE;
+ *imbalance = min(max_pull * busiest->cpu_power,
+ (avg_load - this_load) * this->cpu_power)
+ / SCHED_LOAD_SCALE;
- if (*imbalance < SCHED_LOAD_SCALE - 1) {
+ if (*imbalance < SCHED_LOAD_SCALE) {
unsigned long pwr_now = 0, pwr_move = 0;
unsigned long tmp;
max_load - tmp);
/* Amount of load we'd add */
- tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power;
- if (max_load < tmp)
- tmp = max_load;
+ if (max_load*busiest->cpu_power <
+ SCHED_LOAD_SCALE*SCHED_LOAD_SCALE)
+ tmp = max_load*busiest->cpu_power/this->cpu_power;
+ else
+ tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power;
pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp);
pwr_move /= SCHED_LOAD_SCALE;
- /* Move if we gain another 8th of a CPU worth of throughput */
- if (pwr_move < pwr_now + SCHED_LOAD_SCALE / 8)
+ /* Move if we gain throughput */
+ if (pwr_move <= pwr_now)
goto out_balanced;
*imbalance = 1;
}
/* Get rid of the scaling factor, rounding down as we divide */
- *imbalance = (*imbalance + 1) / SCHED_LOAD_SCALE;
-
+ *imbalance = *imbalance / SCHED_LOAD_SCALE;
return busiest;
out_balanced:
- if (busiest && (idle == NEWLY_IDLE ||
- (idle == SCHED_IDLE && max_load > SCHED_LOAD_SCALE)) ) {
- *imbalance = 1;
- return busiest;
- }
*imbalance = 0;
return NULL;
/*
* find_busiest_queue - find the busiest runqueue among the cpus in group.
*/
-static runqueue_t *find_busiest_queue(struct sched_group *group)
+static runqueue_t *find_busiest_queue(struct sched_group *group,
+ enum idle_type idle, cpumask_t *cpus)
{
unsigned long load, max_load = 0;
runqueue_t *busiest = NULL;
int i;
for_each_cpu_mask(i, group->cpumask) {
- load = source_load(i);
+ if (!cpu_isset(i, *cpus))
+ continue;
+
+ load = source_load(i, 0);
if (load > max_load) {
max_load = load;
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.
struct sched_group *group;
runqueue_t *busiest;
unsigned long imbalance;
- int nr_moved;
+ int nr_moved, all_pinned = 0;
+ int active_balance = 0;
+ int sd_idle = 0;
+ cpumask_t cpus = CPU_MASK_ALL;
+
+ if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER)
+ sd_idle = 1;
- spin_lock(&this_rq->lock);
schedstat_inc(sd, lb_cnt[idle]);
- group = find_busiest_group(sd, this_cpu, &imbalance, idle);
+redo:
+ group = find_busiest_group(sd, this_cpu, &imbalance, idle,
+ &sd_idle, &cpus);
if (!group) {
schedstat_inc(sd, lb_nobusyg[idle]);
goto out_balanced;
}
- busiest = find_busiest_queue(group);
+ busiest = find_busiest_queue(group, idle, &cpus);
if (!busiest) {
schedstat_inc(sd, lb_nobusyq[idle]);
goto out_balanced;
}
- /*
- * This should be "impossible", but since load
- * balancing is inherently racy and statistical,
- * it could happen in theory.
- */
- if (unlikely(busiest == this_rq)) {
- WARN_ON(1);
- goto out_balanced;
- }
+ BUG_ON(busiest == this_rq);
schedstat_add(sd, lb_imbalance[idle], imbalance);
* still unbalanced. nr_moved simply stays zero, so it is
* correctly treated as an imbalance.
*/
- double_lock_balance(this_rq, busiest);
+ double_rq_lock(this_rq, busiest);
nr_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, idle);
- spin_unlock(&busiest->lock);
+ imbalance, sd, idle, &all_pinned);
+ double_rq_unlock(this_rq, busiest);
+
+ /* All tasks on this runqueue were pinned by CPU affinity */
+ if (unlikely(all_pinned)) {
+ cpu_clear(busiest->cpu, cpus);
+ if (!cpus_empty(cpus))
+ goto redo;
+ goto out_balanced;
+ }
}
- spin_unlock(&this_rq->lock);
if (!nr_moved) {
schedstat_inc(sd, lb_failed[idle]);
sd->nr_balance_failed++;
if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
- int wake = 0;
spin_lock(&busiest->lock);
+
+ /* 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(&busiest->lock);
+ all_pinned = 1;
+ goto out_one_pinned;
+ }
+
if (!busiest->active_balance) {
busiest->active_balance = 1;
busiest->push_cpu = this_cpu;
- wake = 1;
+ active_balance = 1;
}
spin_unlock(&busiest->lock);
- if (wake)
+ 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;
+ 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 {
/*
- * We were unbalanced, but unsuccessful in move_tasks(),
- * so bump the balance_interval to lessen the lock contention.
+ * 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++;
- } else {
- sd->nr_balance_failed = 0;
-
- /* We were unbalanced, so reset the balancing interval */
- sd->balance_interval = sd->min_interval;
+ sd->balance_interval *= 2;
}
+ if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER)
+ return -1;
return nr_moved;
out_balanced:
- spin_unlock(&this_rq->lock);
+ schedstat_inc(sd, lb_balanced[idle]);
+ sd->nr_balance_failed = 0;
+
+out_one_pinned:
/* tune up the balancing interval */
- if (sd->balance_interval < sd->max_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)
+ return -1;
return 0;
}
runqueue_t *busiest = NULL;
unsigned long imbalance;
int nr_moved = 0;
+ int sd_idle = 0;
+ cpumask_t cpus = CPU_MASK_ALL;
+
+ if (sd->flags & SD_SHARE_CPUPOWER)
+ sd_idle = 1;
schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
- group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE);
+redo:
+ group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE,
+ &sd_idle, &cpus);
if (!group) {
schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
- goto out;
+ goto out_balanced;
}
- busiest = find_busiest_queue(group);
- if (!busiest || busiest == this_rq) {
+ busiest = find_busiest_queue(group, NEWLY_IDLE, &cpus);
+ if (!busiest) {
schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
- goto out;
+ goto out_balanced;
}
- /* Attempt to move tasks */
- double_lock_balance(this_rq, busiest);
+ BUG_ON(busiest == this_rq);
schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance);
- nr_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, NEWLY_IDLE);
- if (!nr_moved)
- schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
- spin_unlock(&busiest->lock);
+ nr_moved = 0;
+ if (busiest->nr_running > 1) {
+ /* Attempt to move tasks */
+ double_lock_balance(this_rq, busiest);
+ nr_moved = move_tasks(this_rq, this_cpu, busiest,
+ imbalance, sd, NEWLY_IDLE, NULL);
+ spin_unlock(&busiest->lock);
+
+ if (!nr_moved) {
+ cpu_clear(busiest->cpu, cpus);
+ if (!cpus_empty(cpus))
+ goto redo;
+ }
+ }
+
+ if (!nr_moved) {
+ schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
+ if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER)
+ return -1;
+ } else
+ sd->nr_balance_failed = 0;
-out:
return nr_moved;
-}
-#endif /* CONFIG_CKRM_CPU_SCHEDULE*/
+out_balanced:
+ schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
+ if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER)
+ 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 inline void idle_balance(int this_cpu, runqueue_t *this_rq)
+static void idle_balance(int this_cpu, runqueue_t *this_rq)
{
struct sched_domain *sd;
}
}
-#ifdef CONFIG_SCHED_SMT
-static int cpu_and_siblings_are_idle(int cpu)
-{
- int sib;
- for_each_cpu_mask(sib, cpu_sibling_map[cpu]) {
- if (idle_cpu(sib))
- continue;
- return 0;
- }
-
- return 1;
-}
-#else
-#define cpu_and_siblings_are_idle(A) idle_cpu(A)
-#endif
-
-
/*
* 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
static void active_load_balance(runqueue_t *busiest_rq, int busiest_cpu)
{
struct sched_domain *sd;
- struct sched_group *cpu_group;
- cpumask_t visited_cpus;
+ runqueue_t *target_rq;
+ int target_cpu = busiest_rq->push_cpu;
+
+ if (busiest_rq->nr_running <= 1)
+ /* no task to move */
+ return;
+
+ target_rq = cpu_rq(target_cpu);
- schedstat_inc(busiest_rq, alb_cnt);
/*
- * Search for suitable CPUs to push tasks to in successively higher
- * domains with SD_LOAD_BALANCE set.
+ * This condition is "impossible", if it occurs
+ * we need to fix it. Originally reported by
+ * Bjorn Helgaas on a 128-cpu setup.
*/
- visited_cpus = CPU_MASK_NONE;
- for_each_domain(busiest_cpu, sd) {
- if (!(sd->flags & SD_LOAD_BALANCE) || busiest_rq->nr_running <= 1)
- break; /* no more domains to search or no more tasks to move */
-
- cpu_group = sd->groups;
- do { /* sched_groups should either use list_heads or be merged into the domains structure */
- int cpu, target_cpu = -1;
- runqueue_t *target_rq;
-
- for_each_cpu_mask(cpu, cpu_group->cpumask) {
- if (cpu_isset(cpu, visited_cpus) || cpu == busiest_cpu ||
- !cpu_and_siblings_are_idle(cpu)) {
- cpu_set(cpu, visited_cpus);
- continue;
- }
- target_cpu = cpu;
+ BUG_ON(busiest_rq == target_rq);
+
+ /* move a task from busiest_rq to target_rq */
+ double_lock_balance(busiest_rq, 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 (target_cpu == -1)
- goto next_group; /* failed to find a suitable target cpu in this domain */
- target_rq = cpu_rq(target_cpu);
+ if (unlikely(sd == NULL))
+ goto out;
- /*
- * This condition is "impossible", if it occurs we need to fix it
- * 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);
- if (move_tasks(target_rq, target_cpu, busiest_rq, 1, sd, SCHED_IDLE)) {
- schedstat_inc(busiest_rq, alb_lost);
- schedstat_inc(target_rq, alb_gained);
- } else {
- schedstat_inc(busiest_rq, alb_failed);
- }
- spin_unlock(&target_rq->lock);
-next_group:
- cpu_group = cpu_group->next;
- } while (cpu_group != sd->groups && busiest_rq->nr_running > 1);
- }
+ schedstat_inc(sd, alb_cnt);
+
+ if (move_tasks(target_rq, target_cpu, busiest_rq, 1, sd, SCHED_IDLE, NULL))
+ schedstat_inc(sd, alb_pushed);
+ else
+ schedstat_inc(sd, alb_failed);
+out:
+ spin_unlock(&target_rq->lock);
}
/*
unsigned long old_load, this_load;
unsigned long j = jiffies + CPU_OFFSET(this_cpu);
struct sched_domain *sd;
+ int i;
- /* Update our load */
- old_load = this_rq->cpu_load;
this_load = this_rq->nr_running * SCHED_LOAD_SCALE;
- /*
- * 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 (this_load > old_load)
- old_load++;
- this_rq->cpu_load = (old_load + this_load) / 2;
+ /* Update our load */
+ for (i = 0; i < 3; i++) {
+ unsigned long new_load = this_load;
+ int scale = 1 << i;
+ old_load = this_rq->cpu_load[i];
+ /*
+ * 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) / scale;
+ }
for_each_domain(this_cpu, sd) {
unsigned long interval;
if (j - sd->last_balance >= interval) {
if (load_balance(this_cpu, this_rq, sd, idle)) {
- /* We've pulled tasks over so no longer idle */
+ /*
+ * We've pulled tasks over so either we're no
+ * longer idle, or one of our SMT siblings is
+ * not idle.
+ */
idle = NOT_IDLE;
}
sd->last_balance += interval;
}
}
}
-#else /* SMP*/
+#else
/*
* on UP we do not need to balance between CPUs:
*/
}
DEFINE_PER_CPU(struct kernel_stat, kstat);
+
EXPORT_PER_CPU_SYMBOL(kstat);
+/*
+ * This is called on clock ticks and on context switches.
+ * Bank in p->sched_time the ns elapsed since the last tick or switch.
+ */
+static inline void update_cpu_clock(task_t *p, runqueue_t *rq,
+ unsigned long long now)
+{
+ unsigned long long last = max(p->timestamp, rq->timestamp_last_tick);
+ p->sched_time += now - last;
+}
+
+/*
+ * Return current->sched_time plus any more ns on the sched_clock
+ * that have not yet been banked.
+ */
+unsigned long long current_sched_time(const task_t *tsk)
+{
+ unsigned long long ns;
+ unsigned long flags;
+ local_irq_save(flags);
+ ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick);
+ ns = tsk->sched_time + (sched_clock() - ns);
+ local_irq_restore(flags);
+ return ns;
+}
+
/*
* We place interactive tasks back into the active array, if possible.
*
* increasing number of running tasks. We also ignore the interactivity
* if a better static_prio task has expired:
*/
-
-#ifndef CONFIG_CKRM_CPU_SCHEDULE
#define EXPIRED_STARVING(rq) \
((STARVATION_LIMIT && ((rq)->expired_timestamp && \
(jiffies - (rq)->expired_timestamp >= \
STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \
((rq)->curr->static_prio > (rq)->best_expired_prio))
-#else
-#define EXPIRED_STARVING(rq) \
- (STARVATION_LIMIT && ((rq)->expired_timestamp && \
- (jiffies - (rq)->expired_timestamp >= \
- STARVATION_LIMIT * (lrq_nr_running(rq)) + 1)))
-#endif
+
+/*
+ * Account user 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 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 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 */
+ runqueue_t *rq = this_rq();
+ cputime64_t tmp;
+
+ 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 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);
+ runqueue_t *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);
+}
/*
* This function gets called by the timer code, with HZ frequency.
* It also gets called by the fork code, when changing the parent's
* timeslices.
*/
-void scheduler_tick(int user_ticks, int sys_ticks)
+void scheduler_tick(void)
{
int cpu = smp_processor_id();
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
runqueue_t *rq = this_rq();
task_t *p = current;
- struct vx_info *vxi = p->vx_info;
-
- rq->timestamp_last_tick = sched_clock();
+ unsigned long long now = sched_clock();
- if (rcu_pending(cpu))
- rcu_check_callbacks(cpu, user_ticks);
+ update_cpu_clock(p, rq, now);
+ rq->timestamp_last_tick = now;
- if (vxi) {
- vxi->sched.cpu[cpu].user_ticks += user_ticks;
- vxi->sched.cpu[cpu].sys_ticks += sys_ticks;
- }
-
- /* note: this timer irq context must be accounted for as well */
- if (hardirq_count() - HARDIRQ_OFFSET) {
- cpustat->irq += sys_ticks;
- sys_ticks = 0;
- } else if (softirq_count()) {
- cpustat->softirq += sys_ticks;
- sys_ticks = 0;
- }
+#if defined(CONFIG_VSERVER_HARDCPU) && defined(CONFIG_VSERVER_ACB_SCHED)
+ vx_scheduler_tick();
+#endif
if (p == rq->idle) {
- if (atomic_read(&rq->nr_iowait) > 0)
- cpustat->iowait += sys_ticks;
- // vx_cpustat_acc(vxi, iowait, cpu, cpustat, sys_ticks);
- else
- cpustat->idle += sys_ticks;
- // vx_cpustat_acc(vxi, idle, cpu, cpustat, sys_ticks);
-
if (wake_priority_sleeper(rq))
goto out;
- ckrm_sched_tick(jiffies,cpu,rq_ckrm_load(rq));
-
#ifdef CONFIG_VSERVER_HARDCPU_IDLE
if (!--rq->idle_tokens && !list_empty(&rq->hold_queue))
set_need_resched();
rebalance_tick(cpu, rq, SCHED_IDLE);
return;
}
- if (TASK_NICE(p) > 0)
- cpustat->nice += user_ticks;
- else
- cpustat->user += user_ticks;
- cpustat->system += sys_ticks;
/* Task might have expired already, but not scheduled off yet */
- if (p->array != rq_active(p,rq)) {
+ if (p->array != rq->active) {
set_tsk_need_resched(p);
goto out;
}
* RR tasks need a special form of timeslice management.
* FIFO tasks have no timeslices.
*/
- if ((p->policy == SCHED_RR) && !--p->time_slice) {
+ if ((p->policy == SCHED_RR) && vx_need_resched(p)) {
p->time_slice = task_timeslice(p);
p->first_time_slice = 0;
set_tsk_need_resched(p);
/* put it at the end of the queue: */
- dequeue_task(p, rq_active(p,rq));
- enqueue_task(p, rq_active(p,rq));
+ requeue_task(p, rq->active);
}
goto out_unlock;
}
if (vx_need_resched(p)) {
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- /* Hubertus ... we can abstract this out */
- ckrm_lrq_t* rq = get_task_lrq(p);
-#endif
dequeue_task(p, rq->active);
set_tsk_need_resched(p);
p->prio = effective_prio(p);
rq->expired_timestamp = jiffies;
if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) {
enqueue_task(p, rq->expired);
- if (p->static_prio < this_rq()->best_expired_prio)
- this_rq()->best_expired_prio = p->static_prio;
+ if (p->static_prio < rq->best_expired_prio)
+ rq->best_expired_prio = p->static_prio;
} else
enqueue_task(p, rq->active);
} else {
if (TASK_INTERACTIVE(p) && !((task_timeslice(p) -
p->time_slice) % TIMESLICE_GRANULARITY(p)) &&
(p->time_slice >= TIMESLICE_GRANULARITY(p)) &&
- (p->array == rq_active(p,rq))) {
+ (p->array == rq->active)) {
- dequeue_task(p, rq_active(p,rq));
+ requeue_task(p, rq->active);
set_tsk_need_resched(p);
- p->prio = effective_prio(p);
- enqueue_task(p, rq_active(p,rq));
}
}
out_unlock:
spin_unlock(&rq->lock);
out:
- ckrm_sched_tick(jiffies,cpu,rq_ckrm_load(rq));
rebalance_tick(cpu, rq, NOT_IDLE);
}
#ifdef CONFIG_SCHED_SMT
-static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
+static inline void wakeup_busy_runqueue(runqueue_t *rq)
+{
+ /* If an SMT runqueue is sleeping due to priority reasons wake it up */
+ if (rq->curr == rq->idle && rq->nr_running)
+ resched_task(rq->idle);
+}
+
+static void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
{
- struct sched_domain *sd = this_rq->sd;
+ struct sched_domain *tmp, *sd = NULL;
cpumask_t sibling_map;
int i;
- if (!(sd->flags & SD_SHARE_CPUPOWER))
- return;
-
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- if (prev != rq->idle) {
- unsigned long long run = now - prev->timestamp;
- ckrm_lrq_t * lrq = get_task_lrq(prev);
+ for_each_domain(this_cpu, tmp)
+ if (tmp->flags & SD_SHARE_CPUPOWER)
+ sd = tmp;
- lrq->lrq_load -= task_load(prev);
- cpu_demand_event(&prev->demand_stat,CPU_DEMAND_DESCHEDULE,run);
- lrq->lrq_load += task_load(prev);
+ if (!sd)
+ return;
- cpu_demand_event(get_task_lrq_stat(prev),CPU_DEMAND_DESCHEDULE,run);
- update_local_cvt(prev, run);
- }
-#endif
/*
* Unlock the current runqueue because we have to lock in
* CPU order to avoid deadlocks. Caller knows that we might
for_each_cpu_mask(i, sibling_map) {
runqueue_t *smt_rq = cpu_rq(i);
- /*
- * If an SMT sibling task is sleeping due to priority
- * reasons wake it up now.
- */
- if (smt_rq->curr == smt_rq->idle && smt_rq->nr_running)
- resched_task(smt_rq->idle);
+ wakeup_busy_runqueue(smt_rq);
}
for_each_cpu_mask(i, sibling_map)
*/
}
-static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
+/*
+ * number of 'lost' timeslices this task wont be able to fully
+ * utilize, if another task runs on a sibling. This models the
+ * slowdown effect of other tasks running on siblings:
+ */
+static inline unsigned long smt_slice(task_t *p, struct sched_domain *sd)
+{
+ return p->time_slice * (100 - sd->per_cpu_gain) / 100;
+}
+
+static int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
{
- struct sched_domain *sd = this_rq->sd;
+ struct sched_domain *tmp, *sd = NULL;
cpumask_t sibling_map;
prio_array_t *array;
int ret = 0, i;
task_t *p;
- if (!(sd->flags & SD_SHARE_CPUPOWER))
+ for_each_domain(this_cpu, tmp)
+ if (tmp->flags & SD_SHARE_CPUPOWER)
+ sd = tmp;
+
+ if (!sd)
return 0;
/*
runqueue_t *smt_rq = cpu_rq(i);
task_t *smt_curr = smt_rq->curr;
+ /* Kernel threads do not participate in dependent sleeping */
+ if (!p->mm || !smt_curr->mm || rt_task(p))
+ goto check_smt_task;
+
/*
* If a user task with lower static priority than the
* running task on the SMT sibling is trying to schedule,
* task from using an unfair proportion of the
* physical cpu's resources. -ck
*/
- if (((smt_curr->time_slice * (100 - sd->per_cpu_gain) / 100) >
- task_timeslice(p) || rt_task(smt_curr)) &&
- p->mm && smt_curr->mm && !rt_task(p))
- ret = 1;
+ if (rt_task(smt_curr)) {
+ /*
+ * With real time tasks we run non-rt tasks only
+ * per_cpu_gain% of the time.
+ */
+ if ((jiffies % DEF_TIMESLICE) >
+ (sd->per_cpu_gain * DEF_TIMESLICE / 100))
+ ret = 1;
+ } else
+ if (smt_curr->static_prio < p->static_prio &&
+ !TASK_PREEMPTS_CURR(p, smt_rq) &&
+ smt_slice(smt_curr, sd) > task_timeslice(p))
+ ret = 1;
+
+check_smt_task:
+ if ((!smt_curr->mm && smt_curr != smt_rq->idle) ||
+ rt_task(smt_curr))
+ continue;
+ if (!p->mm) {
+ wakeup_busy_runqueue(smt_rq);
+ continue;
+ }
/*
- * Reschedule a lower priority task on the SMT sibling,
- * or wake it up if it has been put to sleep for priority
- * reasons.
+ * Reschedule a lower priority task on the SMT sibling for
+ * it to be put to sleep, or wake it up if it has been put to
+ * sleep for priority reasons to see if it should run now.
*/
- if ((((p->time_slice * (100 - sd->per_cpu_gain) / 100) >
- task_timeslice(smt_curr) || rt_task(p)) &&
- smt_curr->mm && p->mm && !rt_task(smt_curr)) ||
- (smt_curr == smt_rq->idle && smt_rq->nr_running))
- resched_task(smt_curr);
+ if (rt_task(p)) {
+ if ((jiffies % DEF_TIMESLICE) >
+ (sd->per_cpu_gain * DEF_TIMESLICE / 100))
+ resched_task(smt_curr);
+ } else {
+ if (TASK_PREEMPTS_CURR(p, smt_rq) &&
+ smt_slice(p, sd) > task_timeslice(smt_curr))
+ resched_task(smt_curr);
+ else
+ wakeup_busy_runqueue(smt_rq);
+ }
}
out_unlock:
for_each_cpu_mask(i, sibling_map)
}
#endif
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
+
+void fastcall add_preempt_count(int val)
+{
+ /*
+ * Underflow?
+ */
+ BUG_ON((preempt_count() < 0));
+ preempt_count() += val;
+ /*
+ * Spinlock count overflowing soon?
+ */
+ BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
+}
+EXPORT_SYMBOL(add_preempt_count);
+
+void fastcall sub_preempt_count(int val)
+{
+ /*
+ * Underflow?
+ */
+ BUG_ON(val > preempt_count());
+ /*
+ * Is the spinlock portion underflowing?
+ */
+ BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
+ preempt_count() -= val;
+}
+EXPORT_SYMBOL(sub_preempt_count);
+
+#endif
+
/*
* schedule() is the main scheduler function.
*/
task_t *prev, *next;
runqueue_t *rq;
prio_array_t *array;
+ struct list_head *queue;
unsigned long long now;
unsigned long run_time;
- int cpu;
-#ifdef CONFIG_VSERVER_HARDCPU
+ int cpu, idx, new_prio;
struct vx_info *vxi;
+#ifdef CONFIG_VSERVER_HARDCPU
int maxidle = -HZ;
+# ifdef CONFIG_VSERVER_ACB_SCHED
+ int min_guarantee_ticks = VX_INVALID_TICKS;
+ int min_best_effort_ticks = VX_INVALID_TICKS;
+# endif
#endif
- /*
- * If crash dump is in progress, this other cpu's
- * need to wait until it completes.
- * NB: this code is optimized away for kernels without
- * dumping enabled.
- */
- if (unlikely(dump_oncpu))
- goto dump_scheduling_disabled;
-
-
/*
* 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 (likely(!(current->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)))) {
+ if (likely(!current->exit_state)) {
if (unlikely(in_atomic())) {
printk(KERN_ERR "scheduling while atomic: "
"%s/0x%08x/%d\n",
* The idle thread is not allowed to schedule!
* Remove this check after it has been exercised a bit.
*/
- if (unlikely(current == rq->idle) && current->state != TASK_RUNNING) {
+ if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) {
printk(KERN_ERR "bad: scheduling from the idle thread!\n");
dump_stack();
}
schedstat_inc(rq, sched_cnt);
now = sched_clock();
- if (likely(now - prev->timestamp < NS_MAX_SLEEP_AVG))
+ if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) {
run_time = now - prev->timestamp;
- else
+ if (unlikely((long long)(now - prev->timestamp) < 0))
+ run_time = 0;
+ } else
run_time = NS_MAX_SLEEP_AVG;
/*
- * Tasks with interactive credits get charged less run_time
- * at high sleep_avg to delay them losing their interactive
- * status
+ * Tasks charged proportionately less run_time at high sleep_avg to
+ * delay them losing their interactive status
*/
- if (HIGH_CREDIT(prev))
- run_time /= (CURRENT_BONUS(prev) ? : 1);
+ run_time /= (CURRENT_BONUS(prev) ? : 1);
spin_lock_irq(&rq->lock);
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- if (prev != rq->idle) {
- unsigned long long run = now - prev->timestamp;
- ckrm_lrq_t * lrq = get_task_lrq(prev);
-
- lrq->lrq_load -= task_load(prev);
- cpu_demand_event(&prev->demand_stat,CPU_DEMAND_DESCHEDULE,run);
- lrq->lrq_load += task_load(prev);
-
- cpu_demand_event(get_task_lrq_stat(prev),CPU_DEMAND_DESCHEDULE,run);
- update_local_cvt(prev, run);
- }
-#endif
+ if (unlikely(prev->flags & PF_DEAD))
+ prev->state = EXIT_DEAD;
- if (unlikely(current->flags & PF_DEAD))
- current->state = EXIT_DEAD;
- /*
- * if entering off of a kernel preemption go straight
- * to picking the next task.
- */
switch_count = &prev->nivcsw;
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
switch_count = &prev->nvcsw;
unlikely(signal_pending(prev))))
prev->state = TASK_RUNNING;
else {
- if (prev->state == TASK_UNINTERRUPTIBLE)
+ if (prev->state == TASK_UNINTERRUPTIBLE) {
rq->nr_uninterruptible++;
+ vx_uninterruptible_inc(prev);
+ }
deactivate_task(prev, rq);
}
}
#ifdef CONFIG_VSERVER_HARDCPU
+# ifdef CONFIG_VSERVER_ACB_SCHED
+drain_hold_queue:
+
+ min_guarantee_ticks = VX_INVALID_TICKS;
+ min_best_effort_ticks = VX_INVALID_TICKS;
+
+# endif
if (!list_empty(&rq->hold_queue)) {
struct list_head *l, *n;
int ret;
vxi = next->vx_info;
ret = vx_tokens_recalc(vxi);
- // tokens = vx_tokens_avail(next);
if (ret > 0) {
- list_del(&next->run_list);
- next->state &= ~TASK_ONHOLD;
- // one less waiting
- vx_onhold_dec(vxi);
- array = rq->expired;
- next->prio = MAX_PRIO-1;
- enqueue_task(next, array);
- rq->nr_running++;
- if (next->static_prio < rq->best_expired_prio)
- rq->best_expired_prio = next->static_prio;
-
- // printk("··· %8lu unhold %p [%d]\n", jiffies, next, next->prio);
+ vx_unhold_task(vxi, next, rq);
break;
}
if ((ret < 0) && (maxidle < ret))
maxidle = ret;
+# ifdef CONFIG_VSERVER_ACB_SCHED
+ if (ret < 0) {
+ if (IS_BEST_EFFORT(vxi)) {
+ if (min_best_effort_ticks < ret)
+ min_best_effort_ticks = ret;
+ } else {
+ if (min_guarantee_ticks < ret)
+ min_guarantee_ticks = ret;
+ }
+ }
+# endif
}
}
rq->idle_tokens = -maxidle;
goto go_idle;
}
- /* MEF: CKRM refactored code into rq_get_next_task(); make
- * sure that when upgrading changes are reflected into both
- * versions of the code.
- */
- next = rq_get_next_task(rq);
+ array = rq->active;
+ if (unlikely(!array->nr_active)) {
+ /*
+ * Switch the active and expired arrays.
+ */
+ schedstat_inc(rq, sched_switch);
+ rq->active = rq->expired;
+ rq->expired = array;
+ array = rq->active;
+ rq->expired_timestamp = 0;
+ rq->best_expired_prio = MAX_PRIO;
+ }
+
+ idx = sched_find_first_bit(array->bitmap);
+ queue = array->queue + idx;
+ next = list_entry(queue->next, task_t, run_list);
-#ifdef CONFIG_VSERVER_HARDCPU
vxi = next->vx_info;
+#ifdef CONFIG_VSERVER_HARDCPU
if (vx_info_flags(vxi, VXF_SCHED_PAUSE|VXF_SCHED_HARD, 0)) {
int ret = vx_tokens_recalc(vxi);
if (unlikely(ret <= 0)) {
- if (ret && (rq->idle_tokens > -ret))
- rq->idle_tokens = -ret;
- __deactivate_task(next, rq);
- recalc_task_prio(next, now);
- // a new one on hold
- vx_onhold_inc(vxi);
- next->state |= TASK_ONHOLD;
- list_add_tail(&next->run_list, &rq->hold_queue);
- //printk("··· %8lu hold %p [%d]\n", jiffies, next, next->prio);
+ if (ret) {
+ if ((rq->idle_tokens > -ret))
+ rq->idle_tokens = -ret;
+# ifdef CONFIG_VSERVER_ACB_SCHED
+ if (IS_BEST_EFFORT(vxi)) {
+ if (min_best_effort_ticks < ret)
+ min_best_effort_ticks = ret;
+ } else {
+ if (min_guarantee_ticks < ret)
+ min_guarantee_ticks = ret;
+ }
+# endif
+ }
+ vx_hold_task(vxi, next, rq);
goto pick_next;
}
- }
+ } else /* well, looks ugly but not as ugly as the ifdef-ed version */
#endif
+ if (vx_info_flags(vxi, VXF_SCHED_PRIO, 0))
+ vx_tokens_recalc(vxi);
if (!rt_task(next) && next->activated > 0) {
unsigned long long delta = now - next->timestamp;
+ if (unlikely((long long)(now - next->timestamp) < 0))
+ delta = 0;
if (next->activated == 1)
delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
array = next->array;
- dequeue_task(next, array);
- recalc_task_prio(next, next->timestamp + delta);
- enqueue_task(next, array);
+ new_prio = recalc_task_prio(next, next->timestamp + delta);
+
+ if (unlikely(next->prio != new_prio)) {
+ dequeue_task(next, array);
+ next->prio = new_prio;
+ enqueue_task(next, array);
+ } else
+ requeue_task(next, array);
}
next->activated = 0;
switch_tasks:
+#if defined(CONFIG_VSERVER_HARDCPU) && defined(CONFIG_VSERVER_ACB_SCHED)
+ if (next == rq->idle && !list_empty(&rq->hold_queue)) {
+ if (min_best_effort_ticks != VX_INVALID_TICKS) {
+ vx_advance_best_effort_ticks(-min_best_effort_ticks);
+ goto drain_hold_queue;
+ }
+ if (min_guarantee_ticks != VX_INVALID_TICKS) {
+ vx_advance_guaranteed_ticks(-min_guarantee_ticks);
+ goto drain_hold_queue;
+ }
+ }
+#endif
if (next == rq->idle)
schedstat_inc(rq, sched_goidle);
prefetch(next);
+ prefetch_stack(next);
clear_tsk_need_resched(prev);
rcu_qsctr_inc(task_cpu(prev));
+ update_cpu_clock(prev, rq, now);
+
prev->sleep_avg -= run_time;
- if ((long)prev->sleep_avg <= 0) {
+ if ((long)prev->sleep_avg <= 0)
prev->sleep_avg = 0;
- if (!(HIGH_CREDIT(prev) || LOW_CREDIT(prev)))
- prev->interactive_credit--;
- }
prev->timestamp = prev->last_ran = now;
sched_info_switch(prev, next);
rq->curr = next;
++*switch_count;
- prepare_arch_switch(rq, next);
+ prepare_task_switch(rq, next);
prev = context_switch(rq, prev, next);
barrier();
-
- finish_task_switch(prev);
+ /*
+ * 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);
} else
spin_unlock_irq(&rq->lock);
preempt_enable_no_resched();
if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
goto need_resched;
-
- return;
-
- dump_scheduling_disabled:
- /* allow scheduling only if this is the dumping cpu */
- if (dump_oncpu != smp_processor_id()+1) {
- while (dump_oncpu)
- cpu_relax();
- }
- return;
}
EXPORT_SYMBOL(schedule);
+
#ifdef CONFIG_PREEMPT
/*
* this is is the entry point to schedule() from in-kernel preemption
asmlinkage void __sched preempt_schedule(void)
{
struct thread_info *ti = current_thread_info();
-
+#ifdef CONFIG_PREEMPT_BKL
+ struct task_struct *task = current;
+ int saved_lock_depth;
+#endif
/*
* If there is a non-zero preempt_count or interrupts are disabled,
* we do not want to preempt the current task. Just return..
return;
need_resched:
- ti->preempt_count = PREEMPT_ACTIVE;
+ add_preempt_count(PREEMPT_ACTIVE);
+ /*
+ * We keep the big kernel semaphore locked, but we
+ * clear ->lock_depth so that schedule() doesnt
+ * auto-release the semaphore:
+ */
+#ifdef CONFIG_PREEMPT_BKL
+ saved_lock_depth = task->lock_depth;
+ task->lock_depth = -1;
+#endif
schedule();
- ti->preempt_count = 0;
+#ifdef CONFIG_PREEMPT_BKL
+ task->lock_depth = saved_lock_depth;
+#endif
+ sub_preempt_count(PREEMPT_ACTIVE);
/* we could miss a preemption opportunity between schedule and now */
barrier();
}
EXPORT_SYMBOL(preempt_schedule);
-#endif /* CONFIG_PREEMPT */
-int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, void *key)
+/*
+ * this is 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)
{
- task_t *p = curr->task;
- return try_to_wake_up(p, mode, sync);
-}
+ struct thread_info *ti = current_thread_info();
+#ifdef CONFIG_PREEMPT_BKL
+ struct task_struct *task = current;
+ int saved_lock_depth;
+#endif
+ /* Catch callers which need to be fixed*/
+ BUG_ON(ti->preempt_count || !irqs_disabled());
+
+need_resched:
+ add_preempt_count(PREEMPT_ACTIVE);
+ /*
+ * We keep the big kernel semaphore locked, but we
+ * clear ->lock_depth so that schedule() doesnt
+ * auto-release the semaphore:
+ */
+#ifdef CONFIG_PREEMPT_BKL
+ saved_lock_depth = task->lock_depth;
+ task->lock_depth = -1;
+#endif
+ local_irq_enable();
+ schedule();
+ local_irq_disable();
+#ifdef CONFIG_PREEMPT_BKL
+ task->lock_depth = saved_lock_depth;
+#endif
+ sub_preempt_count(PREEMPT_ACTIVE);
+
+ /* we could miss a preemption opportunity between schedule and now */
+ barrier();
+ if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+ goto need_resched;
+}
+
+#endif /* CONFIG_PREEMPT */
+
+int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
+ void *key)
+{
+ task_t *p = curr->private;
+ return try_to_wake_up(p, mode, sync);
+}
EXPORT_SYMBOL(default_wake_function);
* @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 fastcall __wake_up(wait_queue_head_t *q, unsigned int mode,
- int nr_exclusive, void *key)
+ int nr_exclusive, void *key)
{
unsigned long flags;
}
/**
- * __wake_up - sync- wake up threads blocked on a waitqueue.
+ * __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
*
* On UP it can prevent extra preemption.
*/
-void fastcall __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+void fastcall
+__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
{
unsigned long flags;
int sync = 1;
}
EXPORT_SYMBOL(wait_for_completion);
+unsigned long fastcall __sched
+wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+ might_sleep();
+
+ spin_lock_irq(&x->wait.lock);
+ if (!x->done) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ wait.flags |= WQ_FLAG_EXCLUSIVE;
+ __add_wait_queue_tail(&x->wait, &wait);
+ do {
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_unlock_irq(&x->wait.lock);
+ timeout = schedule_timeout(timeout);
+ spin_lock_irq(&x->wait.lock);
+ if (!timeout) {
+ __remove_wait_queue(&x->wait, &wait);
+ goto out;
+ }
+ } while (!x->done);
+ __remove_wait_queue(&x->wait, &wait);
+ }
+ x->done--;
+out:
+ spin_unlock_irq(&x->wait.lock);
+ return timeout;
+}
+EXPORT_SYMBOL(wait_for_completion_timeout);
+
+int fastcall __sched wait_for_completion_interruptible(struct completion *x)
+{
+ int ret = 0;
+
+ might_sleep();
+
+ spin_lock_irq(&x->wait.lock);
+ if (!x->done) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ wait.flags |= WQ_FLAG_EXCLUSIVE;
+ __add_wait_queue_tail(&x->wait, &wait);
+ do {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ __remove_wait_queue(&x->wait, &wait);
+ goto out;
+ }
+ __set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock_irq(&x->wait.lock);
+ schedule();
+ spin_lock_irq(&x->wait.lock);
+ } while (!x->done);
+ __remove_wait_queue(&x->wait, &wait);
+ }
+ x->done--;
+out:
+ spin_unlock_irq(&x->wait.lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible);
+
+unsigned long fastcall __sched
+wait_for_completion_interruptible_timeout(struct completion *x,
+ unsigned long timeout)
+{
+ might_sleep();
+
+ spin_lock_irq(&x->wait.lock);
+ if (!x->done) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ wait.flags |= WQ_FLAG_EXCLUSIVE;
+ __add_wait_queue_tail(&x->wait, &wait);
+ do {
+ if (signal_pending(current)) {
+ timeout = -ERESTARTSYS;
+ __remove_wait_queue(&x->wait, &wait);
+ goto out;
+ }
+ __set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock_irq(&x->wait.lock);
+ timeout = schedule_timeout(timeout);
+ spin_lock_irq(&x->wait.lock);
+ if (!timeout) {
+ __remove_wait_queue(&x->wait, &wait);
+ goto out;
+ }
+ } while (!x->done);
+ __remove_wait_queue(&x->wait, &wait);
+ }
+ x->done--;
+out:
+ spin_unlock_irq(&x->wait.lock);
+ return timeout;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+
+
#define SLEEP_ON_VAR \
unsigned long flags; \
wait_queue_t wait; \
__remove_wait_queue(q, &wait); \
spin_unlock_irqrestore(&q->lock, flags);
-#define SLEEP_ON_BKLCHECK \
- if (unlikely(!kernel_locked()) && \
- sleep_on_bkl_warnings < 10) { \
- sleep_on_bkl_warnings++; \
- WARN_ON(1); \
- }
-
-static int sleep_on_bkl_warnings;
-
void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q)
{
SLEEP_ON_VAR
- SLEEP_ON_BKLCHECK
-
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
EXPORT_SYMBOL(interruptible_sleep_on);
-long fastcall __sched interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
+long fastcall __sched
+interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
SLEEP_ON_VAR
- SLEEP_ON_BKLCHECK
-
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
EXPORT_SYMBOL(interruptible_sleep_on_timeout);
-long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
+void fastcall __sched sleep_on(wait_queue_head_t *q)
{
SLEEP_ON_VAR
- SLEEP_ON_BKLCHECK
+ current->state = TASK_UNINTERRUPTIBLE;
+
+ SLEEP_ON_HEAD
+ schedule();
+ SLEEP_ON_TAIL
+}
+
+EXPORT_SYMBOL(sleep_on);
+
+long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
+{
+ SLEEP_ON_VAR
current->state = TASK_UNINTERRUPTIBLE;
*/
rq = task_rq_lock(p, &flags);
/*
- * The RT priorities are set via setscheduler(), but we still
+ * 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
- * not SCHED_NORMAL:
+ * not SCHED_NORMAL/SCHED_BATCH:
*/
if (rt_task(p)) {
p->static_prio = NICE_TO_PRIO(nice);
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 task_t *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
/*
* We don't have to worry. Conceptually one call occurs first
* and we have a single winner.
*/
- if (increment < 0) {
- if (vx_flags(VXF_IGNEG_NICE, 0))
- return 0;
- if (!capable(CAP_SYS_NICE))
- return -EPERM;
- if (increment < -40)
- increment = -40;
- }
+ if (increment < -40)
+ increment = -40;
if (increment > 40)
increment = 40;
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;
{
return TASK_NICE(p);
}
+EXPORT_SYMBOL_GPL(task_nice);
/**
* idle_cpu - is a given cpu idle currently?
return cpu_curr(cpu) == cpu_rq(cpu)->idle;
}
-EXPORT_SYMBOL_GPL(idle_cpu);
+/**
+ * idle_task - return the idle task for a given cpu.
+ * @cpu: the processor in question.
+ */
+task_t *idle_task(int cpu)
+{
+ return cpu_rq(cpu)->idle;
+}
/**
* find_process_by_pid - find a process with a matching PID value.
BUG_ON(p->array);
p->policy = policy;
p->rt_priority = prio;
- if (policy != SCHED_NORMAL)
- p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority;
- else
+ if (policy != SCHED_NORMAL && policy != SCHED_BATCH) {
+ p->prio = MAX_RT_PRIO-1 - p->rt_priority;
+ } else {
p->prio = p->static_prio;
+ /*
+ * SCHED_BATCH tasks are treated as perpetual CPU hogs:
+ */
+ if (policy == SCHED_BATCH)
+ p->sleep_avg = 0;
+ }
}
-/*
- * setscheduler - change the scheduling policy and/or RT priority of a thread.
+/**
+ * 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.
*/
-static int setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+int sched_setscheduler(struct task_struct *p, int policy,
+ struct sched_param *param)
{
- struct sched_param lp;
- int retval = -EINVAL;
+ int retval;
int oldprio, oldpolicy = -1;
prio_array_t *array;
unsigned long flags;
runqueue_t *rq;
- task_t *p;
-
- if (!param || pid < 0)
- goto out_nounlock;
-
- retval = -EFAULT;
- if (copy_from_user(&lp, param, sizeof(struct sched_param)))
- goto out_nounlock;
- /*
- * We play safe to avoid deadlocks.
- */
- read_lock_irq(&tasklist_lock);
-
- p = find_process_by_pid(pid);
-
- retval = -ESRCH;
- if (!p)
- goto out_unlock;
recheck:
/* double check policy once rq lock held */
if (policy < 0)
policy = oldpolicy = p->policy;
- else {
- retval = -EINVAL;
- if (policy != SCHED_FIFO && policy != SCHED_RR &&
- policy != SCHED_NORMAL)
- goto out_unlock;
- }
+ else if (policy != SCHED_FIFO && policy != SCHED_RR &&
+ policy != SCHED_NORMAL && policy != SCHED_BATCH)
+ return -EINVAL;
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are
- * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL is 0.
+ * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and
+ * SCHED_BATCH is 0.
*/
- retval = -EINVAL;
- if (lp.sched_priority < 0 || lp.sched_priority > MAX_USER_RT_PRIO-1)
- goto out_unlock;
- if ((policy == SCHED_NORMAL) != (lp.sched_priority == 0))
- goto out_unlock;
+ 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 ((policy == SCHED_NORMAL || policy == SCHED_BATCH)
+ != (param->sched_priority == 0))
+ return -EINVAL;
- retval = -EPERM;
- if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
- !capable(CAP_SYS_NICE))
- goto out_unlock;
- if ((current->euid != p->euid) && (current->euid != p->uid) &&
- !capable(CAP_SYS_NICE))
- goto out_unlock;
+ /*
+ * Allow unprivileged RT tasks to decrease priority:
+ */
+ if (!capable(CAP_SYS_NICE)) {
+ /*
+ * can't change policy, except between SCHED_NORMAL
+ * and SCHED_BATCH:
+ */
+ if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) &&
+ (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) &&
+ !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
+ return -EPERM;
+ /* can't increase priority */
+ if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) &&
+ param->sched_priority > p->rt_priority &&
+ param->sched_priority >
+ p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
+ return -EPERM;
+ /* can't change other user's priorities */
+ if ((current->euid != p->euid) &&
+ (current->euid != p->uid))
+ return -EPERM;
+ }
- retval = security_task_setscheduler(p, policy, &lp);
+ retval = security_task_setscheduler(p, policy, param);
if (retval)
- goto out_unlock;
+ return retval;
/*
* To be able to change p->policy safely, the apropriate
* runqueue lock must be held.
}
array = p->array;
if (array)
- deactivate_task(p, task_rq(p));
- retval = 0;
+ deactivate_task(p, rq);
oldprio = p->prio;
- __setscheduler(p, policy, lp.sched_priority);
+ __setscheduler(p, policy, param->sched_priority);
if (array) {
vx_activate_task(p);
- __activate_task(p, task_rq(p));
+ __activate_task(p, rq);
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
resched_task(rq->curr);
}
task_rq_unlock(rq, &flags);
-out_unlock:
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sched_setscheduler);
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+ int retval;
+ struct sched_param lparam;
+ struct task_struct *p;
+
+ if (!param || pid < 0)
+ return -EINVAL;
+ if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+ return -EFAULT;
+ read_lock_irq(&tasklist_lock);
+ p = find_process_by_pid(pid);
+ if (!p) {
+ read_unlock_irq(&tasklist_lock);
+ return -ESRCH;
+ }
+ retval = sched_setscheduler(p, policy, &lparam);
read_unlock_irq(&tasklist_lock);
-out_nounlock:
return retval;
}
/**
* sys_sched_setscheduler - set/change the scheduler policy and RT priority
* @pid: the pid in question.
- * @policy: new policy
+ * @policy: new policy.
* @param: structure containing the new RT priority.
*/
asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
struct sched_param __user *param)
{
- return setscheduler(pid, policy, param);
+ /* negative values for policy are not valid */
+ if (policy < 0)
+ return -EINVAL;
+
+ return do_sched_setscheduler(pid, policy, param);
}
/**
*/
asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
{
- return setscheduler(pid, -1, param);
+ return do_sched_setscheduler(pid, -1, param);
}
/**
{
task_t *p;
int retval;
+ cpumask_t cpus_allowed;
lock_cpu_hotplug();
read_lock(&tasklist_lock);
!capable(CAP_SYS_NICE))
goto out_unlock;
+ cpus_allowed = cpuset_cpus_allowed(p);
+ cpus_and(new_mask, new_mask, cpus_allowed);
retval = set_cpus_allowed(p, new_mask);
out_unlock:
* method, such as ACPI for e.g.
*/
-cpumask_t cpu_present_map;
+cpumask_t cpu_present_map __read_mostly;
EXPORT_SYMBOL(cpu_present_map);
#ifndef CONFIG_SMP
-cpumask_t cpu_online_map = CPU_MASK_ALL;
-cpumask_t cpu_possible_map = CPU_MASK_ALL;
+cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
#endif
long sched_getaffinity(pid_t pid, cpumask_t *mask)
goto out_unlock;
retval = 0;
- cpus_and(*mask, p->cpus_allowed, cpu_possible_map);
+ cpus_and(*mask, p->cpus_allowed, cpu_online_map);
out_unlock:
read_unlock(&tasklist_lock);
{
runqueue_t *rq = this_rq_lock();
prio_array_t *array = current->array;
- prio_array_t *target = rq_expired(current,rq);
+ prio_array_t *target = rq->expired;
schedstat_inc(rq, yld_cnt);
/*
* array.)
*/
if (rt_task(current))
- target = rq_active(current,rq);
+ target = rq->active;
-#warning MEF need to fix up SCHEDSTATS code, but I hope this is fixed by the 2.6.10 CKRM patch
-#ifdef CONFIG_SCHEDSTATS
- if (current->array->nr_active == 1) {
+ if (array->nr_active == 1) {
schedstat_inc(rq, yld_act_empty);
if (!rq->expired->nr_active)
schedstat_inc(rq, yld_both_empty);
} else if (!rq->expired->nr_active)
schedstat_inc(rq, yld_exp_empty);
-#endif
- dequeue_task(current, array);
- enqueue_task(current, target);
+ if (array != target) {
+ dequeue_task(current, array);
+ enqueue_task(current, target);
+ } else
+ /*
+ * requeue_task is cheaper so perform that if possible.
+ */
+ requeue_task(current, array);
/*
* Since we are going to call schedule() anyway, there's
return 0;
}
-void __sched __cond_resched(void)
+static inline void __cond_resched(void)
{
- set_current_state(TASK_RUNNING);
- schedule();
+ /*
+ * The BKS might be reacquired before we have dropped
+ * PREEMPT_ACTIVE, which could trigger a second
+ * cond_resched() call.
+ */
+ if (unlikely(preempt_count()))
+ return;
+ if (unlikely(system_state != SYSTEM_RUNNING))
+ return;
+ do {
+ add_preempt_count(PREEMPT_ACTIVE);
+ schedule();
+ sub_preempt_count(PREEMPT_ACTIVE);
+ } while (need_resched());
+}
+
+int __sched cond_resched(void)
+{
+ if (need_resched()) {
+ __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 ret = 0;
+
+ if (need_lockbreak(lock)) {
+ spin_unlock(lock);
+ cpu_relax();
+ ret = 1;
+ spin_lock(lock);
+ }
+ if (need_resched()) {
+ _raw_spin_unlock(lock);
+ preempt_enable_no_resched();
+ __cond_resched();
+ 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()) {
+ __local_bh_enable();
+ __cond_resched();
+ local_bh_disable();
+ return 1;
+ }
+ return 0;
}
-EXPORT_SYMBOL(__cond_resched);
+EXPORT_SYMBOL(cond_resched_softirq);
+
/**
* yield - yield the current processor to other threads.
*/
void __sched io_schedule(void)
{
- struct runqueue *rq = this_rq();
+ struct runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id());
atomic_inc(&rq->nr_iowait);
schedule();
long __sched io_schedule_timeout(long timeout)
{
- struct runqueue *rq = this_rq();
+ struct runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id());
long ret;
atomic_inc(&rq->nr_iowait);
ret = MAX_USER_RT_PRIO-1;
break;
case SCHED_NORMAL:
+ case SCHED_BATCH:
ret = 0;
break;
}
ret = 1;
break;
case SCHED_NORMAL:
+ case SCHED_BATCH:
ret = 0;
}
return ret;
return list_entry(p->sibling.next,struct task_struct,sibling);
}
-static void show_task(task_t * p)
+static void show_task(task_t *p)
{
task_t *relative;
unsigned state;
#endif
#ifdef CONFIG_DEBUG_STACK_USAGE
{
- unsigned long * n = (unsigned long *) (p->thread_info+1);
+ unsigned long *n = end_of_stack(p);
while (!*n)
n++;
- free = (unsigned long) n - (unsigned long)(p->thread_info+1);
+ free = (unsigned long)n - (unsigned long)end_of_stack(p);
}
#endif
printk("%5lu %5d %6d ", free, p->pid, p->parent->pid);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+ mutex_debug_show_all_locks();
}
-EXPORT_SYMBOL_GPL(show_state);
-
+/**
+ * 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 __devinit init_idle(task_t *idle, int cpu)
{
runqueue_t *rq = cpu_rq(cpu);
unsigned long flags;
+ idle->timestamp = sched_clock();
idle->sleep_avg = 0;
- idle->interactive_credit = 0;
idle->array = NULL;
idle->prio = MAX_PRIO;
idle->state = TASK_RUNNING;
+ idle->cpus_allowed = cpumask_of_cpu(cpu);
set_task_cpu(idle, cpu);
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- cpu_demand_event(&(idle->demand_stat),CPU_DEMAND_INIT,0);
- idle->cpu_class = get_default_cpu_class();
- idle->array = NULL;
-#endif
-
spin_lock_irqsave(&rq->lock, flags);
rq->curr = rq->idle = idle;
- set_tsk_need_resched(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! */
-#ifdef CONFIG_PREEMPT
- idle->thread_info->preempt_count = (idle->lock_depth >= 0);
+#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
+ task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
#else
- idle->thread_info->preempt_count = 0;
+ task_thread_info(idle)->preempt_count = 0;
#endif
}
if (!cpu_isset(dest_cpu, p->cpus_allowed))
goto out;
+ set_task_cpu(p, dest_cpu);
if (p->array) {
/*
* Sync timestamp with rq_dest's before activating.
p->timestamp = p->timestamp - rq_src->timestamp_last_tick
+ rq_dest->timestamp_last_tick;
deactivate_task(p, rq_src);
- set_task_cpu(p, dest_cpu);
activate_task(p, rq_dest, 0);
if (TASK_PREEMPTS_CURR(p, rq_dest))
resched_task(rq_dest->curr);
- } else
- set_task_cpu(p, dest_cpu);
+ }
out:
double_rq_unlock(rq_src, rq_dest);
* thread migration by bumping thread off CPU then 'pushing' onto
* another runqueue.
*/
-static int migration_thread(void * data)
+static int migration_thread(void *data)
{
runqueue_t *rq;
int cpu = (long)data;
struct list_head *head;
migration_req_t *req;
- if (current->flags & PF_FREEZE)
- refrigerator(PF_FREEZE);
+ try_to_freeze();
spin_lock_irq(&rq->lock);
req = list_entry(head->next, migration_req_t, list);
list_del_init(head->next);
- if (req->type == REQ_MOVE_TASK) {
- spin_unlock(&rq->lock);
- __migrate_task(req->task, smp_processor_id(),
- req->dest_cpu);
- local_irq_enable();
- } else if (req->type == REQ_SET_DOMAIN) {
- rq->sd = req->sd;
- spin_unlock_irq(&rq->lock);
- } else {
- spin_unlock_irq(&rq->lock);
- WARN_ON(1);
- }
+ spin_unlock(&rq->lock);
+ __migrate_task(req->task, cpu, req->dest_cpu);
+ local_irq_enable();
complete(&req->done);
}
spin_unlock_irqrestore(&rq->lock, flags);
}
-static void migrate_dead(unsigned int dead_cpu, task_t *tsk)
+/* 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);
+}
+
+static void migrate_dead(unsigned int dead_cpu, task_t *tsk)
{
struct runqueue *rq = cpu_rq(dead_cpu);
#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
/* Unbind it from offline cpu so it can run. Fall thru. */
- kthread_bind(cpu_rq(cpu)->migration_thread,smp_processor_id());
+ 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;
migration_req_t *req;
req = list_entry(rq->migration_queue.next,
migration_req_t, list);
- BUG_ON(req->type != REQ_MOVE_TASK);
list_del_init(&req->list);
complete(&req->done);
}
#endif
#ifdef CONFIG_SMP
+#undef SCHED_DOMAIN_DEBUG
+#ifdef SCHED_DOMAIN_DEBUG
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+ 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);
+
+ do {
+ int i;
+ char str[NR_CPUS];
+ struct sched_group *group = sd->groups;
+ cpumask_t groupmask;
+
+ cpumask_scnprintf(str, NR_CPUS, sd->span);
+ cpus_clear(groupmask);
+
+ printk(KERN_DEBUG);
+ for (i = 0; i < level + 1; i++)
+ printk(" ");
+ printk("domain %d: ", 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");
+ break;
+ }
+
+ printk("span %s\n", str);
+
+ 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);
+ for (i = 0; i < level + 2; i++)
+ printk(" ");
+ printk("groups:");
+ do {
+ if (!group) {
+ printk("\n");
+ printk(KERN_ERR "ERROR: group is NULL\n");
+ break;
+ }
+
+ if (!group->cpu_power) {
+ printk("\n");
+ printk(KERN_ERR "ERROR: domain->cpu_power not set\n");
+ }
+
+ if (!cpus_weight(group->cpumask)) {
+ printk("\n");
+ printk(KERN_ERR "ERROR: empty group\n");
+ }
+
+ if (cpus_intersects(groupmask, group->cpumask)) {
+ printk("\n");
+ printk(KERN_ERR "ERROR: repeated CPUs\n");
+ }
+
+ cpus_or(groupmask, groupmask, group->cpumask);
+
+ cpumask_scnprintf(str, NR_CPUS, group->cpumask);
+ printk(" %s", str);
+
+ group = group->next;
+ } while (group != sd->groups);
+ printk("\n");
+
+ if (!cpus_equal(sd->span, groupmask))
+ printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+ level++;
+ sd = sd->parent;
+
+ if (sd) {
+ if (!cpus_subset(groupmask, sd->span))
+ printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
+ }
+
+ } while (sd);
+}
+#else
+#define sched_domain_debug(sd, cpu) {}
+#endif
+
+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)) {
+ 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);
+ }
+ if (~cflags & pflags)
+ return 0;
+
+ return 1;
+}
+
/*
* Attach the domain 'sd' to 'cpu' as its base domain. Callers must
* hold the hotplug lock.
*/
-void __devinit cpu_attach_domain(struct sched_domain *sd, int cpu)
+static void cpu_attach_domain(struct sched_domain *sd, int cpu)
{
- migration_req_t req;
- unsigned long flags;
runqueue_t *rq = cpu_rq(cpu);
- int local = 1;
-
- spin_lock_irqsave(&rq->lock, flags);
+ struct sched_domain *tmp;
- if (cpu == smp_processor_id() || !cpu_online(cpu)) {
- rq->sd = sd;
- } else {
- init_completion(&req.done);
- req.type = REQ_SET_DOMAIN;
- req.sd = sd;
- list_add(&req.list, &rq->migration_queue);
- local = 0;
+ /* Remove the sched domains which do not contribute to scheduling. */
+ for (tmp = sd; tmp; tmp = tmp->parent) {
+ struct sched_domain *parent = tmp->parent;
+ if (!parent)
+ break;
+ if (sd_parent_degenerate(tmp, parent))
+ tmp->parent = parent->parent;
}
- spin_unlock_irqrestore(&rq->lock, flags);
+ if (sd && sd_degenerate(sd))
+ sd = sd->parent;
- if (!local) {
- wake_up_process(rq->migration_thread);
- wait_for_completion(&req.done);
- }
+ sched_domain_debug(sd, cpu);
+
+ rcu_assign_pointer(rq->sd, sd);
}
/* cpus with isolated domains */
-cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE;
+static cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE;
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
int ints[NR_CPUS], i;
- str = get_options(str, ARRAY_SIZE(ints), ints);
- cpus_clear(cpu_isolated_map);
- for (i = 1; i <= ints[0]; i++)
- cpu_set(ints[i], cpu_isolated_map);
- return 1;
+ 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 an array of groups, the cpumask we wish
+ * to span, and a pointer to a function which identifies what group a CPU
+ * belongs to. The return value of group_fn must be a valid index into the
+ * groups[] array, and must be >= 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(struct sched_group groups[], cpumask_t span,
+ int (*group_fn)(int cpu))
+{
+ struct sched_group *first = NULL, *last = NULL;
+ cpumask_t covered = CPU_MASK_NONE;
+ int i;
+
+ for_each_cpu_mask(i, span) {
+ int group = group_fn(i);
+ struct sched_group *sg = &groups[group];
+ int j;
+
+ if (cpu_isset(i, covered))
+ continue;
+
+ sg->cpumask = CPU_MASK_NONE;
+ sg->cpu_power = 0;
+
+ for_each_cpu_mask(j, span) {
+ if (group_fn(j) != 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
+
+/*
+ * Self-tuning task migration cost measurement between source and target CPUs.
+ *
+ * This is done by measuring the cost of manipulating buffers of varying
+ * sizes. For a given buffer-size here are the steps that are taken:
+ *
+ * 1) the source CPU reads+dirties a shared buffer
+ * 2) the target CPU reads+dirties the same shared buffer
+ *
+ * We measure how long they take, in the following 4 scenarios:
+ *
+ * - source: CPU1, target: CPU2 | cost1
+ * - source: CPU2, target: CPU1 | cost2
+ * - source: CPU1, target: CPU1 | cost3
+ * - source: CPU2, target: CPU2 | cost4
+ *
+ * We then calculate the cost3+cost4-cost1-cost2 difference - this is
+ * the cost of migration.
+ *
+ * We then start off from a small buffer-size and iterate up to larger
+ * buffer sizes, in 5% steps - measuring each buffer-size separately, and
+ * doing a maximum search for the cost. (The maximum cost for a migration
+ * normally occurs when the working set size is around the effective cache
+ * size.)
+ */
+#define SEARCH_SCOPE 2
+#define MIN_CACHE_SIZE (64*1024U)
+#define DEFAULT_CACHE_SIZE (5*1024*1024U)
+#define ITERATIONS 1
+#define SIZE_THRESH 130
+#define COST_THRESH 130
+
+/*
+ * The migration cost is a function of 'domain distance'. Domain
+ * distance is the number of steps a CPU has to iterate down its
+ * domain tree to share a domain with the other CPU. The farther
+ * two CPUs are from each other, the larger the distance gets.
+ *
+ * Note that we use the distance only to cache measurement results,
+ * the distance value is not used numerically otherwise. When two
+ * CPUs have the same distance it is assumed that the migration
+ * cost is the same. (this is a simplification but quite practical)
+ */
+#define MAX_DOMAIN_DISTANCE 32
+
+static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] =
+ { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] =
+/*
+ * Architectures may override the migration cost and thus avoid
+ * boot-time calibration. Unit is nanoseconds. Mostly useful for
+ * virtualized hardware:
+ */
+#ifdef CONFIG_DEFAULT_MIGRATION_COST
+ CONFIG_DEFAULT_MIGRATION_COST
+#else
+ -1LL
+#endif
+};
+
+/*
+ * Allow override of migration cost - in units of microseconds.
+ * E.g. migration_cost=1000,2000,3000 will set up a level-1 cost
+ * of 1 msec, level-2 cost of 2 msecs and level3 cost of 3 msecs:
+ */
+static int __init migration_cost_setup(char *str)
+{
+ int ints[MAX_DOMAIN_DISTANCE+1], i;
+
+ str = get_options(str, ARRAY_SIZE(ints), ints);
+
+ printk("#ints: %d\n", ints[0]);
+ for (i = 1; i <= ints[0]; i++) {
+ migration_cost[i-1] = (unsigned long long)ints[i]*1000;
+ printk("migration_cost[%d]: %Ld\n", i-1, migration_cost[i-1]);
+ }
+ return 1;
+}
+
+__setup ("migration_cost=", migration_cost_setup);
+
+/*
+ * Global multiplier (divisor) for migration-cutoff values,
+ * in percentiles. E.g. use a value of 150 to get 1.5 times
+ * longer cache-hot cutoff times.
+ *
+ * (We scale it from 100 to 128 to long long handling easier.)
+ */
+
+#define MIGRATION_FACTOR_SCALE 128
+
+static unsigned int migration_factor = MIGRATION_FACTOR_SCALE;
+
+static int __init setup_migration_factor(char *str)
+{
+ get_option(&str, &migration_factor);
+ migration_factor = migration_factor * MIGRATION_FACTOR_SCALE / 100;
+ return 1;
+}
+
+__setup("migration_factor=", setup_migration_factor);
+
+/*
+ * Estimated distance of two CPUs, measured via the number of domains
+ * we have to pass for the two CPUs to be in the same span:
+ */
+static unsigned long domain_distance(int cpu1, int cpu2)
+{
+ unsigned long distance = 0;
+ struct sched_domain *sd;
+
+ for_each_domain(cpu1, sd) {
+ WARN_ON(!cpu_isset(cpu1, sd->span));
+ if (cpu_isset(cpu2, sd->span))
+ return distance;
+ distance++;
+ }
+ if (distance >= MAX_DOMAIN_DISTANCE) {
+ WARN_ON(1);
+ distance = MAX_DOMAIN_DISTANCE-1;
+ }
+
+ return distance;
+}
+
+static unsigned int migration_debug;
+
+static int __init setup_migration_debug(char *str)
+{
+ get_option(&str, &migration_debug);
+ return 1;
+}
+
+__setup("migration_debug=", setup_migration_debug);
+
+/*
+ * Maximum cache-size that the scheduler should try to measure.
+ * Architectures with larger caches should tune this up during
+ * bootup. Gets used in the domain-setup code (i.e. during SMP
+ * bootup).
+ */
+unsigned int max_cache_size;
+
+static int __init setup_max_cache_size(char *str)
+{
+ get_option(&str, &max_cache_size);
+ return 1;
+}
+
+__setup("max_cache_size=", setup_max_cache_size);
+
+/*
+ * Dirty a big buffer in a hard-to-predict (for the L2 cache) way. This
+ * is the operation that is timed, so we try to generate unpredictable
+ * cachemisses that still end up filling the L2 cache:
+ */
+static void touch_cache(void *__cache, unsigned long __size)
+{
+ unsigned long size = __size/sizeof(long), chunk1 = size/3,
+ chunk2 = 2*size/3;
+ unsigned long *cache = __cache;
+ int i;
+
+ for (i = 0; i < size/6; i += 8) {
+ switch (i % 6) {
+ case 0: cache[i]++;
+ case 1: cache[size-1-i]++;
+ case 2: cache[chunk1-i]++;
+ case 3: cache[chunk1+i]++;
+ case 4: cache[chunk2-i]++;
+ case 5: cache[chunk2+i]++;
+ }
+ }
+}
+
+/*
+ * Measure the cache-cost of one task migration. Returns in units of nsec.
+ */
+static unsigned long long measure_one(void *cache, unsigned long size,
+ int source, int target)
+{
+ cpumask_t mask, saved_mask;
+ unsigned long long t0, t1, t2, t3, cost;
+
+ saved_mask = current->cpus_allowed;
+
+ /*
+ * Flush source caches to RAM and invalidate them:
+ */
+ sched_cacheflush();
+
+ /*
+ * Migrate to the source CPU:
+ */
+ mask = cpumask_of_cpu(source);
+ set_cpus_allowed(current, mask);
+ WARN_ON(smp_processor_id() != source);
+
+ /*
+ * Dirty the working set:
+ */
+ t0 = sched_clock();
+ touch_cache(cache, size);
+ t1 = sched_clock();
+
+ /*
+ * Migrate to the target CPU, dirty the L2 cache and access
+ * the shared buffer. (which represents the working set
+ * of a migrated task.)
+ */
+ mask = cpumask_of_cpu(target);
+ set_cpus_allowed(current, mask);
+ WARN_ON(smp_processor_id() != target);
+
+ t2 = sched_clock();
+ touch_cache(cache, size);
+ t3 = sched_clock();
+
+ cost = t1-t0 + t3-t2;
+
+ if (migration_debug >= 2)
+ printk("[%d->%d]: %8Ld %8Ld %8Ld => %10Ld.\n",
+ source, target, t1-t0, t1-t0, t3-t2, cost);
+ /*
+ * Flush target caches to RAM and invalidate them:
+ */
+ sched_cacheflush();
+
+ set_cpus_allowed(current, saved_mask);
+
+ return cost;
+}
+
+/*
+ * Measure a series of task migrations and return the average
+ * result. Since this code runs early during bootup the system
+ * is 'undisturbed' and the average latency makes sense.
+ *
+ * The algorithm in essence auto-detects the relevant cache-size,
+ * so it will properly detect different cachesizes for different
+ * cache-hierarchies, depending on how the CPUs are connected.
+ *
+ * Architectures can prime the upper limit of the search range via
+ * max_cache_size, otherwise the search range defaults to 20MB...64K.
+ */
+static unsigned long long
+measure_cost(int cpu1, int cpu2, void *cache, unsigned int size)
+{
+ unsigned long long cost1, cost2;
+ int i;
+
+ /*
+ * Measure the migration cost of 'size' bytes, over an
+ * average of 10 runs:
+ *
+ * (We perturb the cache size by a small (0..4k)
+ * value to compensate size/alignment related artifacts.
+ * We also subtract the cost of the operation done on
+ * the same CPU.)
+ */
+ cost1 = 0;
+
+ /*
+ * dry run, to make sure we start off cache-cold on cpu1,
+ * and to get any vmalloc pagefaults in advance:
+ */
+ measure_one(cache, size, cpu1, cpu2);
+ for (i = 0; i < ITERATIONS; i++)
+ cost1 += measure_one(cache, size - i*1024, cpu1, cpu2);
+
+ measure_one(cache, size, cpu2, cpu1);
+ for (i = 0; i < ITERATIONS; i++)
+ cost1 += measure_one(cache, size - i*1024, cpu2, cpu1);
+
+ /*
+ * (We measure the non-migrating [cached] cost on both
+ * cpu1 and cpu2, to handle CPUs with different speeds)
+ */
+ cost2 = 0;
+
+ measure_one(cache, size, cpu1, cpu1);
+ for (i = 0; i < ITERATIONS; i++)
+ cost2 += measure_one(cache, size - i*1024, cpu1, cpu1);
+
+ measure_one(cache, size, cpu2, cpu2);
+ for (i = 0; i < ITERATIONS; i++)
+ cost2 += measure_one(cache, size - i*1024, cpu2, cpu2);
+
+ /*
+ * Get the per-iteration migration cost:
+ */
+ do_div(cost1, 2*ITERATIONS);
+ do_div(cost2, 2*ITERATIONS);
+
+ return cost1 - cost2;
+}
+
+static unsigned long long measure_migration_cost(int cpu1, int cpu2)
+{
+ unsigned long long max_cost = 0, fluct = 0, avg_fluct = 0;
+ unsigned int max_size, size, size_found = 0;
+ long long cost = 0, prev_cost;
+ void *cache;
+
+ /*
+ * Search from max_cache_size*5 down to 64K - the real relevant
+ * cachesize has to lie somewhere inbetween.
+ */
+ if (max_cache_size) {
+ max_size = max(max_cache_size * SEARCH_SCOPE, MIN_CACHE_SIZE);
+ size = max(max_cache_size / SEARCH_SCOPE, MIN_CACHE_SIZE);
+ } else {
+ /*
+ * Since we have no estimation about the relevant
+ * search range
+ */
+ max_size = DEFAULT_CACHE_SIZE * SEARCH_SCOPE;
+ size = MIN_CACHE_SIZE;
+ }
+
+ if (!cpu_online(cpu1) || !cpu_online(cpu2)) {
+ printk("cpu %d and %d not both online!\n", cpu1, cpu2);
+ return 0;
+ }
+
+ /*
+ * Allocate the working set:
+ */
+ cache = vmalloc(max_size);
+ if (!cache) {
+ printk("could not vmalloc %d bytes for cache!\n", 2*max_size);
+ return 1000000; // return 1 msec on very small boxen
+ }
+
+ while (size <= max_size) {
+ prev_cost = cost;
+ cost = measure_cost(cpu1, cpu2, cache, size);
+
+ /*
+ * Update the max:
+ */
+ if (cost > 0) {
+ if (max_cost < cost) {
+ max_cost = cost;
+ size_found = size;
+ }
+ }
+ /*
+ * Calculate average fluctuation, we use this to prevent
+ * noise from triggering an early break out of the loop:
+ */
+ fluct = abs(cost - prev_cost);
+ avg_fluct = (avg_fluct + fluct)/2;
+
+ if (migration_debug)
+ printk("-> [%d][%d][%7d] %3ld.%ld [%3ld.%ld] (%ld): (%8Ld %8Ld)\n",
+ cpu1, cpu2, size,
+ (long)cost / 1000000,
+ ((long)cost / 100000) % 10,
+ (long)max_cost / 1000000,
+ ((long)max_cost / 100000) % 10,
+ domain_distance(cpu1, cpu2),
+ cost, avg_fluct);
+
+ /*
+ * If we iterated at least 20% past the previous maximum,
+ * and the cost has dropped by more than 20% already,
+ * (taking fluctuations into account) then we assume to
+ * have found the maximum and break out of the loop early:
+ */
+ if (size_found && (size*100 > size_found*SIZE_THRESH))
+ if (cost+avg_fluct <= 0 ||
+ max_cost*100 > (cost+avg_fluct)*COST_THRESH) {
+
+ if (migration_debug)
+ printk("-> found max.\n");
+ break;
+ }
+ /*
+ * Increase the cachesize in 10% steps:
+ */
+ size = size * 10 / 9;
+ }
+
+ if (migration_debug)
+ printk("[%d][%d] working set size found: %d, cost: %Ld\n",
+ cpu1, cpu2, size_found, max_cost);
+
+ vfree(cache);
+
+ /*
+ * A task is considered 'cache cold' if at least 2 times
+ * the worst-case cost of migration has passed.
+ *
+ * (this limit is only listened to if the load-balancing
+ * situation is 'nice' - if there is a large imbalance we
+ * ignore it for the sake of CPU utilization and
+ * processing fairness.)
+ */
+ return 2 * max_cost * migration_factor / MIGRATION_FACTOR_SCALE;
+}
+
+static void calibrate_migration_costs(const cpumask_t *cpu_map)
+{
+ int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id();
+ unsigned long j0, j1, distance, max_distance = 0;
+ struct sched_domain *sd;
+
+ j0 = jiffies;
+
+ /*
+ * First pass - calculate the cacheflush times:
+ */
+ for_each_cpu_mask(cpu1, *cpu_map) {
+ for_each_cpu_mask(cpu2, *cpu_map) {
+ if (cpu1 == cpu2)
+ continue;
+ distance = domain_distance(cpu1, cpu2);
+ max_distance = max(max_distance, distance);
+ /*
+ * No result cached yet?
+ */
+ if (migration_cost[distance] == -1LL)
+ migration_cost[distance] =
+ measure_migration_cost(cpu1, cpu2);
+ }
+ }
+ /*
+ * Second pass - update the sched domain hierarchy with
+ * the new cache-hot-time estimations:
+ */
+ for_each_cpu_mask(cpu, *cpu_map) {
+ distance = 0;
+ for_each_domain(cpu, sd) {
+ sd->cache_hot_time = migration_cost[distance];
+ distance++;
+ }
+ }
+ /*
+ * Print the matrix:
+ */
+ if (migration_debug)
+ printk("migration: max_cache_size: %d, cpu: %d MHz:\n",
+ max_cache_size,
+#ifdef CONFIG_X86
+ cpu_khz/1000
+#else
+ -1
+#endif
+ );
+ if (system_state == SYSTEM_BOOTING) {
+ printk("migration_cost=");
+ for (distance = 0; distance <= max_distance; distance++) {
+ if (distance)
+ printk(",");
+ printk("%ld", (long)migration_cost[distance] / 1000);
+ }
+ printk("\n");
+ }
+ j1 = jiffies;
+ if (migration_debug)
+ printk("migration: %ld seconds\n", (j1-j0)/HZ);
+
+ /*
+ * Move back to the original CPU. NUMA-Q gets confused
+ * if we migrate to another quad during bootup.
+ */
+ if (raw_smp_processor_id() != orig_cpu) {
+ cpumask_t mask = cpumask_of_cpu(orig_cpu),
+ saved_mask = current->cpus_allowed;
+
+ set_cpus_allowed(current, mask);
+ set_cpus_allowed(current, saved_mask);
+ }
}
-__setup ("isolcpus=", isolated_cpu_setup);
+#ifdef CONFIG_NUMA
-/*
- * init_sched_build_groups takes an array of groups, the cpumask we wish
- * to span, and a pointer to a function which identifies what group a CPU
- * belongs to. The return value of group_fn must be a valid index into the
- * groups[] array, and must be >= 0 and < NR_CPUS (due to the fact that we
- * keep track of groups covered with a cpumask_t).
+/**
+ * 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
*
- * 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.
+ * 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.
*/
-void __devinit init_sched_build_groups(struct sched_group groups[],
- cpumask_t span, int (*group_fn)(int cpu))
+static int find_next_best_node(int node, unsigned long *used_nodes)
{
- struct sched_group *first = NULL, *last = NULL;
- cpumask_t covered = CPU_MASK_NONE;
- int i;
+ int i, n, val, min_val, best_node = 0;
- for_each_cpu_mask(i, span) {
- int group = group_fn(i);
- struct sched_group *sg = &groups[group];
- int j;
+ min_val = INT_MAX;
- if (cpu_isset(i, covered))
+ for (i = 0; i < MAX_NUMNODES; i++) {
+ /* Start at @node */
+ n = (node + i) % MAX_NUMNODES;
+
+ if (!nr_cpus_node(n))
continue;
- sg->cpumask = CPU_MASK_NONE;
- sg->cpu_power = 0;
+ /* Skip already used nodes */
+ if (test_bit(n, used_nodes))
+ continue;
- for_each_cpu_mask(j, span) {
- if (group_fn(j) != group)
- continue;
+ /* Simple min distance search */
+ val = node_distance(node, n);
- cpu_set(j, covered);
- cpu_set(j, sg->cpumask);
+ if (val < min_val) {
+ min_val = val;
+ best_node = n;
}
- if (!first)
- first = sg;
- if (last)
- last->next = sg;
- last = sg;
}
- last->next = first;
+
+ set_bit(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
+ * @size: number of nodes to include in this span
+ *
+ * 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 cpumask_t sched_domain_node_span(int node)
+{
+ int i;
+ cpumask_t span, nodemask;
+ DECLARE_BITMAP(used_nodes, MAX_NUMNODES);
+
+ cpus_clear(span);
+ bitmap_zero(used_nodes, MAX_NUMNODES);
-#ifdef ARCH_HAS_SCHED_DOMAIN
-extern void __devinit arch_init_sched_domains(void);
-extern void __devinit arch_destroy_sched_domains(void);
-#else
+ nodemask = node_to_cpumask(node);
+ cpus_or(span, span, nodemask);
+ set_bit(node, used_nodes);
+
+ for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
+ int next_node = find_next_best_node(node, used_nodes);
+ nodemask = node_to_cpumask(next_node);
+ cpus_or(span, span, nodemask);
+ }
+
+ return span;
+}
+#endif
+
+/*
+ * At the moment, CONFIG_SCHED_SMT is never defined, but leave it in so we
+ * can switch it on easily if needed.
+ */
#ifdef CONFIG_SCHED_SMT
static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
static struct sched_group sched_group_cpus[NR_CPUS];
-static int __devinit cpu_to_cpu_group(int cpu)
+static int cpu_to_cpu_group(int cpu)
{
return cpu;
}
static DEFINE_PER_CPU(struct sched_domain, phys_domains);
static struct sched_group sched_group_phys[NR_CPUS];
-static int __devinit cpu_to_phys_group(int cpu)
+static int cpu_to_phys_group(int cpu)
{
#ifdef CONFIG_SCHED_SMT
return first_cpu(cpu_sibling_map[cpu]);
}
#ifdef CONFIG_NUMA
-
-static DEFINE_PER_CPU(struct sched_domain, node_domains);
-static struct sched_group sched_group_nodes[MAX_NUMNODES];
-static int __devinit cpu_to_node_group(int cpu)
-{
- return cpu_to_node(cpu);
-}
-#endif
-
-#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
/*
- * The domains setup code relies on siblings not spanning
- * multiple nodes. Make sure the architecture has a proper
- * siblings map:
+ * 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 void check_sibling_maps(void)
-{
- int i, j;
+static DEFINE_PER_CPU(struct sched_domain, node_domains);
+static struct sched_group **sched_group_nodes_bycpu[NR_CPUS];
- for_each_online_cpu(i) {
- for_each_cpu_mask(j, cpu_sibling_map[i]) {
- if (cpu_to_node(i) != cpu_to_node(j)) {
- printk(KERN_INFO "warning: CPU %d siblings map "
- "to different node - isolating "
- "them.\n", i);
- cpu_sibling_map[i] = cpumask_of_cpu(i);
- break;
- }
- }
- }
+static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
+static struct sched_group *sched_group_allnodes_bycpu[NR_CPUS];
+
+static int cpu_to_allnodes_group(int cpu)
+{
+ return cpu_to_node(cpu);
}
#endif
/*
- * Set up scheduler domains and groups. Callers must hold the hotplug lock.
+ * Build sched domains for a given set of cpus and attach the sched domains
+ * to the individual cpus
*/
-static void __devinit arch_init_sched_domains(void)
+void build_sched_domains(const cpumask_t *cpu_map)
{
int i;
- cpumask_t cpu_default_map;
+#ifdef CONFIG_NUMA
+ struct sched_group **sched_group_nodes = NULL;
+ struct sched_group *sched_group_allnodes = NULL;
-#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
- check_sibling_maps();
-#endif
/*
- * Setup mask for cpus without special case scheduling requirements.
- * For now this just excludes isolated cpus, but could be used to
- * exclude other special cases in the future.
+ * Allocate the per-node list of sched groups
*/
- cpus_complement(cpu_default_map, cpu_isolated_map);
- cpus_and(cpu_default_map, cpu_default_map, cpu_online_map);
+ sched_group_nodes = kmalloc(sizeof(struct sched_group*)*MAX_NUMNODES,
+ GFP_ATOMIC);
+ if (!sched_group_nodes) {
+ printk(KERN_WARNING "Can not alloc sched group node list\n");
+ return;
+ }
+ sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
+#endif
/*
- * Set up domains. Isolated domains just stay on the dummy domain.
+ * Set up domains for cpus specified by the cpu_map.
*/
- for_each_cpu_mask(i, cpu_default_map) {
+ for_each_cpu_mask(i, *cpu_map) {
int group;
struct sched_domain *sd = NULL, *p;
cpumask_t nodemask = node_to_cpumask(cpu_to_node(i));
- cpus_and(nodemask, nodemask, cpu_default_map);
+ cpus_and(nodemask, nodemask, *cpu_map);
#ifdef CONFIG_NUMA
+ if (cpus_weight(*cpu_map)
+ > SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
+ if (!sched_group_allnodes) {
+ sched_group_allnodes
+ = kmalloc(sizeof(struct sched_group)
+ * MAX_NUMNODES,
+ GFP_KERNEL);
+ if (!sched_group_allnodes) {
+ printk(KERN_WARNING
+ "Can not alloc allnodes sched group\n");
+ break;
+ }
+ sched_group_allnodes_bycpu[i]
+ = sched_group_allnodes;
+ }
+ sd = &per_cpu(allnodes_domains, i);
+ *sd = SD_ALLNODES_INIT;
+ sd->span = *cpu_map;
+ group = cpu_to_allnodes_group(i);
+ sd->groups = &sched_group_allnodes[group];
+ p = sd;
+ } else
+ p = NULL;
+
sd = &per_cpu(node_domains, i);
- group = cpu_to_node_group(i);
*sd = SD_NODE_INIT;
- sd->span = cpu_default_map;
- sd->groups = &sched_group_nodes[group];
+ sd->span = sched_domain_node_span(cpu_to_node(i));
+ sd->parent = p;
+ cpus_and(sd->span, sd->span, *cpu_map);
#endif
p = sd;
group = cpu_to_cpu_group(i);
*sd = SD_SIBLING_INIT;
sd->span = cpu_sibling_map[i];
- cpus_and(sd->span, sd->span, cpu_default_map);
+ cpus_and(sd->span, sd->span, *cpu_map);
sd->parent = p;
sd->groups = &sched_group_cpus[group];
#endif
#ifdef CONFIG_SCHED_SMT
/* Set up CPU (sibling) groups */
- for_each_online_cpu(i) {
+ for_each_cpu_mask(i, *cpu_map) {
cpumask_t this_sibling_map = cpu_sibling_map[i];
- cpus_and(this_sibling_map, this_sibling_map, cpu_default_map);
+ cpus_and(this_sibling_map, this_sibling_map, *cpu_map);
if (i != first_cpu(this_sibling_map))
continue;
for (i = 0; i < MAX_NUMNODES; i++) {
cpumask_t nodemask = node_to_cpumask(i);
- cpus_and(nodemask, nodemask, cpu_default_map);
+ cpus_and(nodemask, nodemask, *cpu_map);
if (cpus_empty(nodemask))
continue;
&cpu_to_phys_group);
}
-
#ifdef CONFIG_NUMA
/* Set up node groups */
- init_sched_build_groups(sched_group_nodes, cpu_default_map,
- &cpu_to_node_group);
-#endif
+ if (sched_group_allnodes)
+ init_sched_build_groups(sched_group_allnodes, *cpu_map,
+ &cpu_to_allnodes_group);
+
+ for (i = 0; i < MAX_NUMNODES; i++) {
+ /* Set up node groups */
+ struct sched_group *sg, *prev;
+ cpumask_t nodemask = node_to_cpumask(i);
+ cpumask_t domainspan;
+ cpumask_t covered = CPU_MASK_NONE;
+ int j;
+
+ cpus_and(nodemask, nodemask, *cpu_map);
+ if (cpus_empty(nodemask)) {
+ sched_group_nodes[i] = NULL;
+ continue;
+ }
+
+ domainspan = sched_domain_node_span(i);
+ cpus_and(domainspan, domainspan, *cpu_map);
+
+ sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL);
+ sched_group_nodes[i] = sg;
+ for_each_cpu_mask(j, nodemask) {
+ struct sched_domain *sd;
+ sd = &per_cpu(node_domains, j);
+ sd->groups = sg;
+ if (sd->groups == NULL) {
+ /* Turn off balancing if we have no groups */
+ sd->flags = 0;
+ }
+ }
+ if (!sg) {
+ printk(KERN_WARNING
+ "Can not alloc domain group for node %d\n", i);
+ continue;
+ }
+ sg->cpu_power = 0;
+ sg->cpumask = nodemask;
+ cpus_or(covered, covered, nodemask);
+ prev = sg;
+
+ for (j = 0; j < MAX_NUMNODES; j++) {
+ cpumask_t tmp, notcovered;
+ int n = (i + j) % MAX_NUMNODES;
+
+ cpus_complement(notcovered, covered);
+ cpus_and(tmp, notcovered, *cpu_map);
+ cpus_and(tmp, tmp, domainspan);
+ if (cpus_empty(tmp))
+ break;
+
+ nodemask = node_to_cpumask(n);
+ cpus_and(tmp, tmp, nodemask);
+ if (cpus_empty(tmp))
+ continue;
+ sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL);
+ if (!sg) {
+ printk(KERN_WARNING
+ "Can not alloc domain group for node %d\n", j);
+ break;
+ }
+ sg->cpu_power = 0;
+ sg->cpumask = tmp;
+ cpus_or(covered, covered, tmp);
+ prev->next = sg;
+ prev = sg;
+ }
+ prev->next = sched_group_nodes[i];
+ }
+#endif
/* Calculate CPU power for physical packages and nodes */
- for_each_cpu_mask(i, cpu_default_map) {
+ for_each_cpu_mask(i, *cpu_map) {
int power;
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
(cpus_weight(sd->groups->cpumask)-1) / 10;
sd->groups->cpu_power = power;
-
#ifdef CONFIG_NUMA
- if (i == first_cpu(sd->groups->cpumask)) {
- /* Only add "power" once for each physical package. */
- sd = &per_cpu(node_domains, i);
- sd->groups->cpu_power += power;
+ sd = &per_cpu(allnodes_domains, i);
+ if (sd->groups) {
+ power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
+ (cpus_weight(sd->groups->cpumask)-1) / 10;
+ sd->groups->cpu_power = power;
}
#endif
}
+#ifdef CONFIG_NUMA
+ for (i = 0; i < MAX_NUMNODES; i++) {
+ struct sched_group *sg = sched_group_nodes[i];
+ int j;
+
+ if (sg == NULL)
+ continue;
+next_sg:
+ for_each_cpu_mask(j, sg->cpumask) {
+ struct sched_domain *sd;
+ int power;
+
+ sd = &per_cpu(phys_domains, j);
+ if (j != first_cpu(sd->groups->cpumask)) {
+ /*
+ * Only add "power" once for each
+ * physical package.
+ */
+ continue;
+ }
+ power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
+ (cpus_weight(sd->groups->cpumask)-1) / 10;
+
+ sg->cpu_power += power;
+ }
+ sg = sg->next;
+ if (sg != sched_group_nodes[i])
+ goto next_sg;
+ }
+#endif
+
/* Attach the domains */
- for_each_online_cpu(i) {
+ for_each_cpu_mask(i, *cpu_map) {
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
sd = &per_cpu(cpu_domains, i);
#endif
cpu_attach_domain(sd, i);
}
- last->next = first;
+ /*
+ * Tune cache-hot values:
+ */
+ calibrate_migration_costs(cpu_map);
}
-
-#ifdef CONFIG_HOTPLUG_CPU
-static void __devinit arch_destroy_sched_domains(void)
+/*
+ * Set up scheduler domains and groups. Callers must hold the hotplug lock.
+ */
+static void arch_init_sched_domains(const cpumask_t *cpu_map)
{
- /* Do nothing: everything is statically allocated. */
-}
-#endif
+ cpumask_t cpu_default_map;
+
+ /*
+ * Setup mask for cpus without special case scheduling requirements.
+ * For now this just excludes isolated cpus, but could be used to
+ * exclude other special cases in the future.
+ */
+ cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map);
-#endif /* ARCH_HAS_SCHED_DOMAIN */
+ build_sched_domains(&cpu_default_map);
+}
-#define SCHED_DOMAIN_DEBUG
-#ifdef SCHED_DOMAIN_DEBUG
-static void sched_domain_debug(void)
+static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
{
+#ifdef CONFIG_NUMA
int i;
+ int cpu;
- for_each_online_cpu(i) {
- runqueue_t *rq = cpu_rq(i);
- struct sched_domain *sd;
- int level = 0;
-
- sd = rq->sd;
-
- printk(KERN_DEBUG "CPU%d:\n", i);
-
- do {
- int j;
- char str[NR_CPUS];
- struct sched_group *group = sd->groups;
- cpumask_t groupmask;
-
- cpumask_scnprintf(str, NR_CPUS, sd->span);
- cpus_clear(groupmask);
-
- printk(KERN_DEBUG);
- for (j = 0; j < level + 1; j++)
- printk(" ");
- printk("domain %d: ", level);
-
- if (!(sd->flags & SD_LOAD_BALANCE)) {
- printk("does not load-balance");
- if (sd->parent)
- printk(" ERROR !SD_LOAD_BALANCE domain has parent");
- printk("\n");
- break;
- }
-
- printk("span %s\n", str);
-
- if (!cpu_isset(i, sd->span))
- printk(KERN_DEBUG "ERROR domain->span does not contain CPU%d\n", i);
- if (!cpu_isset(i, group->cpumask))
- printk(KERN_DEBUG "ERROR domain->groups does not contain CPU%d\n", i);
-
- printk(KERN_DEBUG);
- for (j = 0; j < level + 2; j++)
- printk(" ");
- printk("groups:");
- do {
- if (!group) {
- printk(" ERROR: NULL");
- break;
- }
-
- if (!group->cpu_power)
- printk(KERN_DEBUG "ERROR group->cpu_power not set\n");
-
- if (!cpus_weight(group->cpumask))
- printk(" ERROR empty group:");
-
- if (cpus_intersects(groupmask, group->cpumask))
- printk(" ERROR repeated CPUs:");
+ for_each_cpu_mask(cpu, *cpu_map) {
+ struct sched_group *sched_group_allnodes
+ = sched_group_allnodes_bycpu[cpu];
+ struct sched_group **sched_group_nodes
+ = sched_group_nodes_bycpu[cpu];
- cpus_or(groupmask, groupmask, group->cpumask);
+ if (sched_group_allnodes) {
+ kfree(sched_group_allnodes);
+ sched_group_allnodes_bycpu[cpu] = NULL;
+ }
- cpumask_scnprintf(str, NR_CPUS, group->cpumask);
- printk(" %s", str);
+ if (!sched_group_nodes)
+ continue;
- group = group->next;
- } while (group != sd->groups);
- printk("\n");
+ for (i = 0; i < MAX_NUMNODES; i++) {
+ cpumask_t nodemask = node_to_cpumask(i);
+ struct sched_group *oldsg, *sg = sched_group_nodes[i];
- if (!cpus_equal(sd->span, groupmask))
- printk(KERN_DEBUG "ERROR groups don't span domain->span\n");
+ cpus_and(nodemask, nodemask, *cpu_map);
+ if (cpus_empty(nodemask))
+ continue;
- level++;
- sd = sd->parent;
+ 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;
+ }
+#endif
+}
- if (sd) {
- if (!cpus_subset(groupmask, sd->span))
- printk(KERN_DEBUG "ERROR parent span is not a superset of domain->span\n");
- }
+/*
+ * 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)
+{
+ int i;
- } while (sd);
- }
+ for_each_cpu_mask(i, *cpu_map)
+ cpu_attach_domain(NULL, i);
+ synchronize_sched();
+ arch_destroy_sched_domains(cpu_map);
}
-#else
-#define sched_domain_debug() {}
-#endif
/*
- * Initial dummy domain for early boot and for hotplug cpu. Being static,
- * it is initialized to zero, so all balancing flags are cleared which is
- * what we want.
+ * Partition sched domains as specified by the cpumasks below.
+ * This attaches all cpus from the cpumasks to the NULL domain,
+ * waits for a RCU quiescent period, recalculates sched
+ * domain information and then attaches them back to the
+ * correct sched domains
+ * Call with hotplug lock held
*/
-static struct sched_domain sched_domain_dummy;
+void partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2)
+{
+ cpumask_t change_map;
+
+ cpus_and(*partition1, *partition1, cpu_online_map);
+ cpus_and(*partition2, *partition2, cpu_online_map);
+ cpus_or(change_map, *partition1, *partition2);
+
+ /* Detach sched domains from all of the affected cpus */
+ detach_destroy_domains(&change_map);
+ if (!cpus_empty(*partition1))
+ build_sched_domains(partition1);
+ if (!cpus_empty(*partition2))
+ build_sched_domains(partition2);
+}
#ifdef CONFIG_HOTPLUG_CPU
/*
* Force a reinitialization of the sched domains hierarchy. The domains
* and groups cannot be updated in place without racing with the balancing
- * code, so we temporarily attach all running cpus to a "dummy" domain
+ * code, so we temporarily attach all running cpus to the NULL domain
* which will prevent rebalancing while the sched domains are recalculated.
*/
static int update_sched_domains(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
- int i;
-
switch (action) {
case CPU_UP_PREPARE:
case CPU_DOWN_PREPARE:
- for_each_online_cpu(i)
- cpu_attach_domain(&sched_domain_dummy, i);
- arch_destroy_sched_domains();
+ detach_destroy_domains(&cpu_online_map);
return NOTIFY_OK;
case CPU_UP_CANCELED:
}
/* The hotplug lock is already held by cpu_up/cpu_down */
- arch_init_sched_domains();
-
- sched_domain_debug();
+ arch_init_sched_domains(&cpu_online_map);
return NOTIFY_OK;
}
void __init sched_init_smp(void)
{
lock_cpu_hotplug();
- arch_init_sched_domains();
- sched_domain_debug();
+ arch_init_sched_domains(&cpu_online_map);
unlock_cpu_hotplug();
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
void __init sched_init(void)
{
runqueue_t *rq;
- int i;
+ int i, j, k;
- init_cpu_classes();
-
- for (i = 0; i < NR_CPUS; i++) {
-#ifndef CONFIG_CKRM_CPU_SCHEDULE
- int j, k;
+ for_each_cpu(i) {
prio_array_t *array;
rq = cpu_rq(i);
spin_lock_init(&rq->lock);
-
- for (j = 0; j < 2; j++) {
- array = rq->arrays + j;
- for (k = 0; k < MAX_PRIO; k++) {
- INIT_LIST_HEAD(array->queue + k);
- __clear_bit(k, array->bitmap);
- }
- // delimiter for bitsearch
- __set_bit(MAX_PRIO, array->bitmap);
- }
-
+ rq->nr_running = 0;
rq->active = rq->arrays;
rq->expired = rq->arrays + 1;
rq->best_expired_prio = MAX_PRIO;
-#else
- rq = cpu_rq(i);
- spin_lock_init(&rq->lock);
-#endif
-
#ifdef CONFIG_SMP
- rq->sd = &sched_domain_dummy;
- rq->cpu_load = 0;
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
- ckrm_load_init(rq_ckrm_load(rq));
-#endif
+ rq->sd = NULL;
+ for (j = 1; j < 3; j++)
+ rq->cpu_load[j] = 0;
rq->active_balance = 0;
rq->push_cpu = 0;
+ rq->cpu = i;
rq->migration_thread = NULL;
INIT_LIST_HEAD(&rq->migration_queue);
+ rq->cpu = i;
#endif
+ atomic_set(&rq->nr_iowait, 0);
#ifdef CONFIG_VSERVER_HARDCPU
INIT_LIST_HEAD(&rq->hold_queue);
#endif
- atomic_set(&rq->nr_iowait, 0);
+ for (j = 0; j < 2; j++) {
+ array = rq->arrays + j;
+ for (k = 0; k < MAX_PRIO; k++) {
+ INIT_LIST_HEAD(array->queue + k);
+ __clear_bit(k, array->bitmap);
+ }
+ // delimiter for bitsearch
+ __set_bit(MAX_PRIO, array->bitmap);
+ }
}
/*
static unsigned long prev_jiffy; /* ratelimiting */
if ((in_atomic() || irqs_disabled()) &&
- system_state == SYSTEM_RUNNING) {
+ system_state == SYSTEM_RUNNING && !oops_in_progress) {
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
return;
prev_jiffy = jiffies;
EXPORT_SYMBOL(__might_sleep);
#endif
-#ifdef CONFIG_CKRM_CPU_SCHEDULE
-/**
- * return the classqueue object of a certain processor
- */
-struct classqueue_struct * get_cpu_classqueue(int cpu)
-{
- return (& (cpu_rq(cpu)->classqueue) );
-}
-
-/**
- * _ckrm_cpu_change_class - change the class of a task
- */
-void _ckrm_cpu_change_class(task_t *tsk, struct ckrm_cpu_class *newcls)
-{
- prio_array_t *array;
- struct runqueue *rq;
- unsigned long flags;
-
- rq = task_rq_lock(tsk,&flags);
- array = tsk->array;
- if (array) {
- dequeue_task(tsk,array);
- tsk->cpu_class = newcls;
- enqueue_task(tsk,rq_active(tsk,rq));
- } else
- tsk->cpu_class = newcls;
-
- task_rq_unlock(rq,&flags);
-}
-#endif
-
#ifdef CONFIG_MAGIC_SYSRQ
void normalize_rt_tasks(void)
{
deactivate_task(p, task_rq(p));
__setscheduler(p, SCHED_NORMAL, 0);
if (array) {
+ vx_activate_task(p);
__activate_task(p, task_rq(p));
resched_task(rq->curr);
}
}
#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!
+ */
+task_t *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, task_t *p)
+{
+ cpu_curr(cpu) = p;
+}
+
+#endif
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