--- /dev/null
+/*
+ * kernel/cpuset.c
+ *
+ * Processor and Memory placement constraints for sets of tasks.
+ *
+ * Copyright (C) 2003 BULL SA.
+ * Copyright (C) 2004 Silicon Graphics, Inc.
+ *
+ * Portions derived from Patrick Mochel's sysfs code.
+ * sysfs is Copyright (c) 2001-3 Patrick Mochel
+ * Portions Copyright (c) 2004 Silicon Graphics, Inc.
+ *
+ * 2003-10-10 Written by Simon Derr <simon.derr@bull.net>
+ * 2003-10-22 Updates by Stephen Hemminger.
+ * 2004 May-July Rework by Paul Jackson <pj@sgi.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+
+#include <linux/config.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/cpuset.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/time.h>
+#include <linux/backing-dev.h>
+#include <linux/sort.h>
+
+#include <asm/uaccess.h>
+#include <asm/atomic.h>
+#include <asm/semaphore.h>
+
+#define CPUSET_SUPER_MAGIC 0x27e0eb
+
+struct cpuset {
+ unsigned long flags; /* "unsigned long" so bitops work */
+ cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
+ nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */
+
+ atomic_t count; /* count tasks using this cpuset */
+
+ /*
+ * We link our 'sibling' struct into our parents 'children'.
+ * Our children link their 'sibling' into our 'children'.
+ */
+ struct list_head sibling; /* my parents children */
+ struct list_head children; /* my children */
+
+ struct cpuset *parent; /* my parent */
+ struct dentry *dentry; /* cpuset fs entry */
+
+ /*
+ * Copy of global cpuset_mems_generation as of the most
+ * recent time this cpuset changed its mems_allowed.
+ */
+ int mems_generation;
+};
+
+/* bits in struct cpuset flags field */
+typedef enum {
+ CS_CPU_EXCLUSIVE,
+ CS_MEM_EXCLUSIVE,
+ CS_REMOVED,
+ CS_NOTIFY_ON_RELEASE
+} cpuset_flagbits_t;
+
+/* convenient tests for these bits */
+static inline int is_cpu_exclusive(const struct cpuset *cs)
+{
+ return !!test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
+}
+
+static inline int is_mem_exclusive(const struct cpuset *cs)
+{
+ return !!test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
+}
+
+static inline int is_removed(const struct cpuset *cs)
+{
+ return !!test_bit(CS_REMOVED, &cs->flags);
+}
+
+static inline int notify_on_release(const struct cpuset *cs)
+{
+ return !!test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
+}
+
+/*
+ * Increment this atomic integer everytime any cpuset changes its
+ * mems_allowed value. Users of cpusets can track this generation
+ * number, and avoid having to lock and reload mems_allowed unless
+ * the cpuset they're using changes generation.
+ *
+ * A single, global generation is needed because attach_task() could
+ * reattach a task to a different cpuset, which must not have its
+ * generation numbers aliased with those of that tasks previous cpuset.
+ *
+ * Generations are needed for mems_allowed because one task cannot
+ * modify anothers memory placement. So we must enable every task,
+ * on every visit to __alloc_pages(), to efficiently check whether
+ * its current->cpuset->mems_allowed has changed, requiring an update
+ * of its current->mems_allowed.
+ */
+static atomic_t cpuset_mems_generation = ATOMIC_INIT(1);
+
+static struct cpuset top_cpuset = {
+ .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
+ .cpus_allowed = CPU_MASK_ALL,
+ .mems_allowed = NODE_MASK_ALL,
+ .count = ATOMIC_INIT(0),
+ .sibling = LIST_HEAD_INIT(top_cpuset.sibling),
+ .children = LIST_HEAD_INIT(top_cpuset.children),
+ .parent = NULL,
+ .dentry = NULL,
+ .mems_generation = 0,
+};
+
+static struct vfsmount *cpuset_mount;
+static struct super_block *cpuset_sb = NULL;
+
+/*
+ * cpuset_sem should be held by anyone who is depending on the children
+ * or sibling lists of any cpuset, or performing non-atomic operations
+ * on the flags or *_allowed values of a cpuset, such as raising the
+ * CS_REMOVED flag bit iff it is not already raised, or reading and
+ * conditionally modifying the *_allowed values. One kernel global
+ * cpuset semaphore should be sufficient - these things don't change
+ * that much.
+ *
+ * The code that modifies cpusets holds cpuset_sem across the entire
+ * operation, from cpuset_common_file_write() down, single threading
+ * all cpuset modifications (except for counter manipulations from
+ * fork and exit) across the system. This presumes that cpuset
+ * modifications are rare - better kept simple and safe, even if slow.
+ *
+ * The code that reads cpusets, such as in cpuset_common_file_read()
+ * and below, only holds cpuset_sem across small pieces of code, such
+ * as when reading out possibly multi-word cpumasks and nodemasks, as
+ * the risks are less, and the desire for performance a little greater.
+ * The proc_cpuset_show() routine needs to hold cpuset_sem to insure
+ * that no cs->dentry is NULL, as it walks up the cpuset tree to root.
+ *
+ * The hooks from fork and exit, cpuset_fork() and cpuset_exit(), don't
+ * (usually) grab cpuset_sem. These are the two most performance
+ * critical pieces of code here. The exception occurs on exit(),
+ * when a task in a notify_on_release cpuset exits. Then cpuset_sem
+ * is taken, and if the cpuset count is zero, a usermode call made
+ * to /sbin/cpuset_release_agent with the name of the cpuset (path
+ * relative to the root of cpuset file system) as the argument.
+ *
+ * A cpuset can only be deleted if both its 'count' of using tasks is
+ * zero, and its list of 'children' cpusets is empty. Since all tasks
+ * in the system use _some_ cpuset, and since there is always at least
+ * one task in the system (init, pid == 1), therefore, top_cpuset
+ * always has either children cpusets and/or using tasks. So no need
+ * for any special hack to ensure that top_cpuset cannot be deleted.
+ */
+
+static DECLARE_MUTEX(cpuset_sem);
+
+/*
+ * A couple of forward declarations required, due to cyclic reference loop:
+ * cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
+ * -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
+ */
+
+static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
+
+static struct backing_dev_info cpuset_backing_dev_info = {
+ .ra_pages = 0, /* No readahead */
+ .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+};
+
+static struct inode *cpuset_new_inode(mode_t mode)
+{
+ struct inode *inode = new_inode(cpuset_sb);
+
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
+ }
+ return inode;
+}
+
+static void cpuset_diput(struct dentry *dentry, struct inode *inode)
+{
+ /* is dentry a directory ? if so, kfree() associated cpuset */
+ if (S_ISDIR(inode->i_mode)) {
+ struct cpuset *cs = dentry->d_fsdata;
+ BUG_ON(!(is_removed(cs)));
+ kfree(cs);
+ }
+ iput(inode);
+}
+
+static struct dentry_operations cpuset_dops = {
+ .d_iput = cpuset_diput,
+};
+
+static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
+{
+ struct qstr qstr;
+ struct dentry *d;
+
+ qstr.name = name;
+ qstr.len = strlen(name);
+ qstr.hash = full_name_hash(name, qstr.len);
+ d = lookup_hash(&qstr, parent);
+ if (!IS_ERR(d))
+ d->d_op = &cpuset_dops;
+ return d;
+}
+
+static void remove_dir(struct dentry *d)
+{
+ struct dentry *parent = dget(d->d_parent);
+
+ d_delete(d);
+ simple_rmdir(parent->d_inode, d);
+ dput(parent);
+}
+
+/*
+ * NOTE : the dentry must have been dget()'ed
+ */
+static void cpuset_d_remove_dir(struct dentry *dentry)
+{
+ struct list_head *node;
+
+ spin_lock(&dcache_lock);
+ node = dentry->d_subdirs.next;
+ while (node != &dentry->d_subdirs) {
+ struct dentry *d = list_entry(node, struct dentry, d_child);
+ list_del_init(node);
+ if (d->d_inode) {
+ d = dget_locked(d);
+ spin_unlock(&dcache_lock);
+ d_delete(d);
+ simple_unlink(dentry->d_inode, d);
+ dput(d);
+ spin_lock(&dcache_lock);
+ }
+ node = dentry->d_subdirs.next;
+ }
+ list_del_init(&dentry->d_child);
+ spin_unlock(&dcache_lock);
+ remove_dir(dentry);
+}
+
+static struct super_operations cpuset_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+};
+
+static int cpuset_fill_super(struct super_block *sb, void *unused_data,
+ int unused_silent)
+{
+ struct inode *inode;
+ struct dentry *root;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = CPUSET_SUPER_MAGIC;
+ sb->s_op = &cpuset_ops;
+ cpuset_sb = sb;
+
+ inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
+ if (inode) {
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ /* directories start off with i_nlink == 2 (for "." entry) */
+ inode->i_nlink++;
+ } else {
+ return -ENOMEM;
+ }
+
+ root = d_alloc_root(inode);
+ if (!root) {
+ iput(inode);
+ return -ENOMEM;
+ }
+ sb->s_root = root;
+ return 0;
+}
+
+static struct super_block *cpuset_get_sb(struct file_system_type *fs_type,
+ int flags, const char *unused_dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, cpuset_fill_super);
+}
+
+static struct file_system_type cpuset_fs_type = {
+ .name = "cpuset",
+ .get_sb = cpuset_get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+/* struct cftype:
+ *
+ * The files in the cpuset filesystem mostly have a very simple read/write
+ * handling, some common function will take care of it. Nevertheless some cases
+ * (read tasks) are special and therefore I define this structure for every
+ * kind of file.
+ *
+ *
+ * When reading/writing to a file:
+ * - the cpuset to use in file->f_dentry->d_parent->d_fsdata
+ * - the 'cftype' of the file is file->f_dentry->d_fsdata
+ */
+
+struct cftype {
+ char *name;
+ int private;
+ int (*open) (struct inode *inode, struct file *file);
+ ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos);
+ int (*write) (struct file *file, const char __user *buf, size_t nbytes,
+ loff_t *ppos);
+ int (*release) (struct inode *inode, struct file *file);
+};
+
+static inline struct cpuset *__d_cs(struct dentry *dentry)
+{
+ return dentry->d_fsdata;
+}
+
+static inline struct cftype *__d_cft(struct dentry *dentry)
+{
+ return dentry->d_fsdata;
+}
+
+/*
+ * Call with cpuset_sem held. Writes path of cpuset into buf.
+ * Returns 0 on success, -errno on error.
+ */
+
+static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
+{
+ char *start;
+
+ start = buf + buflen;
+
+ *--start = '\0';
+ for (;;) {
+ int len = cs->dentry->d_name.len;
+ if ((start -= len) < buf)
+ return -ENAMETOOLONG;
+ memcpy(start, cs->dentry->d_name.name, len);
+ cs = cs->parent;
+ if (!cs)
+ break;
+ if (!cs->parent)
+ continue;
+ if (--start < buf)
+ return -ENAMETOOLONG;
+ *start = '/';
+ }
+ memmove(buf, start, buf + buflen - start);
+ return 0;
+}
+
+/*
+ * Notify userspace when a cpuset is released, by running
+ * /sbin/cpuset_release_agent with the name of the cpuset (path
+ * relative to the root of cpuset file system) as the argument.
+ *
+ * Most likely, this user command will try to rmdir this cpuset.
+ *
+ * This races with the possibility that some other task will be
+ * attached to this cpuset before it is removed, or that some other
+ * user task will 'mkdir' a child cpuset of this cpuset. That's ok.
+ * The presumed 'rmdir' will fail quietly if this cpuset is no longer
+ * unused, and this cpuset will be reprieved from its death sentence,
+ * to continue to serve a useful existence. Next time it's released,
+ * we will get notified again, if it still has 'notify_on_release' set.
+ *
+ * Note final arg to call_usermodehelper() is 0 - that means
+ * don't wait. Since we are holding the global cpuset_sem here,
+ * and we are asking another thread (started from keventd) to rmdir a
+ * cpuset, we can't wait - or we'd deadlock with the removing thread
+ * on cpuset_sem.
+ */
+
+static int cpuset_release_agent(char *cpuset_str)
+{
+ char *argv[3], *envp[3];
+ int i;
+
+ i = 0;
+ argv[i++] = "/sbin/cpuset_release_agent";
+ argv[i++] = cpuset_str;
+ argv[i] = NULL;
+
+ i = 0;
+ /* minimal command environment */
+ envp[i++] = "HOME=/";
+ envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+ envp[i] = NULL;
+
+ return call_usermodehelper(argv[0], argv, envp, 0);
+}
+
+/*
+ * Either cs->count of using tasks transitioned to zero, or the
+ * cs->children list of child cpusets just became empty. If this
+ * cs is notify_on_release() and now both the user count is zero and
+ * the list of children is empty, send notice to user land.
+ */
+
+static void check_for_release(struct cpuset *cs)
+{
+ if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
+ list_empty(&cs->children)) {
+ char *buf;
+
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!buf)
+ return;
+ if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
+ goto out;
+ cpuset_release_agent(buf);
+out:
+ kfree(buf);
+ }
+}
+
+/*
+ * Return in *pmask the portion of a cpusets's cpus_allowed that
+ * are online. If none are online, walk up the cpuset hierarchy
+ * until we find one that does have some online cpus. If we get
+ * all the way to the top and still haven't found any online cpus,
+ * return cpu_online_map. Or if passed a NULL cs from an exit'ing
+ * task, return cpu_online_map.
+ *
+ * One way or another, we guarantee to return some non-empty subset
+ * of cpu_online_map.
+ *
+ * Call with cpuset_sem held.
+ */
+
+static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
+{
+ while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
+ cs = cs->parent;
+ if (cs)
+ cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
+ else
+ *pmask = cpu_online_map;
+ BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
+}
+
+/*
+ * Return in *pmask the portion of a cpusets's mems_allowed that
+ * are online. If none are online, walk up the cpuset hierarchy
+ * until we find one that does have some online mems. If we get
+ * all the way to the top and still haven't found any online mems,
+ * return node_online_map.
+ *
+ * One way or another, we guarantee to return some non-empty subset
+ * of node_online_map.
+ *
+ * Call with cpuset_sem held.
+ */
+
+static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
+{
+ while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
+ cs = cs->parent;
+ if (cs)
+ nodes_and(*pmask, cs->mems_allowed, node_online_map);
+ else
+ *pmask = node_online_map;
+ BUG_ON(!nodes_intersects(*pmask, node_online_map));
+}
+
+/*
+ * Refresh current tasks mems_allowed and mems_generation from
+ * current tasks cpuset. Call with cpuset_sem held.
+ *
+ * Be sure to call refresh_mems() on any cpuset operation which
+ * (1) holds cpuset_sem, and (2) might possibly alloc memory.
+ * Call after obtaining cpuset_sem lock, before any possible
+ * allocation. Otherwise one risks trying to allocate memory
+ * while the task cpuset_mems_generation is not the same as
+ * the mems_generation in its cpuset, which would deadlock on
+ * cpuset_sem in cpuset_update_current_mems_allowed().
+ *
+ * Since we hold cpuset_sem, once refresh_mems() is called, the
+ * test (current->cpuset_mems_generation != cs->mems_generation)
+ * in cpuset_update_current_mems_allowed() will remain false,
+ * until we drop cpuset_sem. Anyone else who would change our
+ * cpusets mems_generation needs to lock cpuset_sem first.
+ */
+
+static void refresh_mems(void)
+{
+ struct cpuset *cs = current->cpuset;
+
+ if (current->cpuset_mems_generation != cs->mems_generation) {
+ guarantee_online_mems(cs, ¤t->mems_allowed);
+ current->cpuset_mems_generation = cs->mems_generation;
+ }
+}
+
+/*
+ * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
+ *
+ * One cpuset is a subset of another if all its allowed CPUs and
+ * Memory Nodes are a subset of the other, and its exclusive flags
+ * are only set if the other's are set.
+ */
+
+static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
+{
+ return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
+ nodes_subset(p->mems_allowed, q->mems_allowed) &&
+ is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
+ is_mem_exclusive(p) <= is_mem_exclusive(q);
+}
+
+/*
+ * validate_change() - Used to validate that any proposed cpuset change
+ * follows the structural rules for cpusets.
+ *
+ * If we replaced the flag and mask values of the current cpuset
+ * (cur) with those values in the trial cpuset (trial), would
+ * our various subset and exclusive rules still be valid? Presumes
+ * cpuset_sem held.
+ *
+ * 'cur' is the address of an actual, in-use cpuset. Operations
+ * such as list traversal that depend on the actual address of the
+ * cpuset in the list must use cur below, not trial.
+ *
+ * 'trial' is the address of bulk structure copy of cur, with
+ * perhaps one or more of the fields cpus_allowed, mems_allowed,
+ * or flags changed to new, trial values.
+ *
+ * Return 0 if valid, -errno if not.
+ */
+
+static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
+{
+ struct cpuset *c, *par;
+
+ /* Each of our child cpusets must be a subset of us */
+ list_for_each_entry(c, &cur->children, sibling) {
+ if (!is_cpuset_subset(c, trial))
+ return -EBUSY;
+ }
+
+ /* Remaining checks don't apply to root cpuset */
+ if ((par = cur->parent) == NULL)
+ return 0;
+
+ /* We must be a subset of our parent cpuset */
+ if (!is_cpuset_subset(trial, par))
+ return -EACCES;
+
+ /* If either I or some sibling (!= me) is exclusive, we can't overlap */
+ list_for_each_entry(c, &par->children, sibling) {
+ if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
+ c != cur &&
+ cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
+ return -EINVAL;
+ if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
+ c != cur &&
+ nodes_intersects(trial->mems_allowed, c->mems_allowed))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int update_cpumask(struct cpuset *cs, char *buf)
+{
+ struct cpuset trialcs;
+ int retval;
+
+ trialcs = *cs;
+ retval = cpulist_parse(buf, trialcs.cpus_allowed);
+ if (retval < 0)
+ return retval;
+ cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
+ if (cpus_empty(trialcs.cpus_allowed))
+ return -ENOSPC;
+ retval = validate_change(cs, &trialcs);
+ if (retval == 0)
+ cs->cpus_allowed = trialcs.cpus_allowed;
+ return retval;
+}
+
+static int update_nodemask(struct cpuset *cs, char *buf)
+{
+ struct cpuset trialcs;
+ int retval;
+
+ trialcs = *cs;
+ retval = nodelist_parse(buf, trialcs.mems_allowed);
+ if (retval < 0)
+ return retval;
+ nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
+ if (nodes_empty(trialcs.mems_allowed))
+ return -ENOSPC;
+ retval = validate_change(cs, &trialcs);
+ if (retval == 0) {
+ cs->mems_allowed = trialcs.mems_allowed;
+ atomic_inc(&cpuset_mems_generation);
+ cs->mems_generation = atomic_read(&cpuset_mems_generation);
+ }
+ return retval;
+}
+
+/*
+ * update_flag - read a 0 or a 1 in a file and update associated flag
+ * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
+ * CS_NOTIFY_ON_RELEASE)
+ * cs: the cpuset to update
+ * buf: the buffer where we read the 0 or 1
+ */
+
+static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
+{
+ int turning_on;
+ struct cpuset trialcs;
+ int err;
+
+ turning_on = (simple_strtoul(buf, NULL, 10) != 0);
+
+ trialcs = *cs;
+ if (turning_on)
+ set_bit(bit, &trialcs.flags);
+ else
+ clear_bit(bit, &trialcs.flags);
+
+ err = validate_change(cs, &trialcs);
+ if (err == 0) {
+ if (turning_on)
+ set_bit(bit, &cs->flags);
+ else
+ clear_bit(bit, &cs->flags);
+ }
+ return err;
+}
+
+static int attach_task(struct cpuset *cs, char *buf)
+{
+ pid_t pid;
+ struct task_struct *tsk;
+ struct cpuset *oldcs;
+ cpumask_t cpus;
+
+ if (sscanf(buf, "%d", &pid) != 1)
+ return -EIO;
+ if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
+ return -ENOSPC;
+
+ if (pid) {
+ read_lock(&tasklist_lock);
+
+ tsk = find_task_by_pid(pid);
+ if (!tsk) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+
+ get_task_struct(tsk);
+ read_unlock(&tasklist_lock);
+
+ if ((current->euid) && (current->euid != tsk->uid)
+ && (current->euid != tsk->suid)) {
+ put_task_struct(tsk);
+ return -EACCES;
+ }
+ } else {
+ tsk = current;
+ get_task_struct(tsk);
+ }
+
+ task_lock(tsk);
+ oldcs = tsk->cpuset;
+ if (!oldcs) {
+ task_unlock(tsk);
+ put_task_struct(tsk);
+ return -ESRCH;
+ }
+ atomic_inc(&cs->count);
+ tsk->cpuset = cs;
+ task_unlock(tsk);
+
+ guarantee_online_cpus(cs, &cpus);
+ set_cpus_allowed(tsk, cpus);
+
+ put_task_struct(tsk);
+ if (atomic_dec_and_test(&oldcs->count))
+ check_for_release(oldcs);
+ return 0;
+}
+
+/* The various types of files and directories in a cpuset file system */
+
+typedef enum {
+ FILE_ROOT,
+ FILE_DIR,
+ FILE_CPULIST,
+ FILE_MEMLIST,
+ FILE_CPU_EXCLUSIVE,
+ FILE_MEM_EXCLUSIVE,
+ FILE_NOTIFY_ON_RELEASE,
+ FILE_TASKLIST,
+} cpuset_filetype_t;
+
+static ssize_t cpuset_common_file_write(struct file *file, const char __user *userbuf,
+ size_t nbytes, loff_t *unused_ppos)
+{
+ struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
+ struct cftype *cft = __d_cft(file->f_dentry);
+ cpuset_filetype_t type = cft->private;
+ char *buffer;
+ int retval = 0;
+
+ /* Crude upper limit on largest legitimate cpulist user might write. */
+ if (nbytes > 100 + 6 * NR_CPUS)
+ return -E2BIG;
+
+ /* +1 for nul-terminator */
+ if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0)
+ return -ENOMEM;
+
+ if (copy_from_user(buffer, userbuf, nbytes)) {
+ retval = -EFAULT;
+ goto out1;
+ }
+ buffer[nbytes] = 0; /* nul-terminate */
+
+ down(&cpuset_sem);
+
+ if (is_removed(cs)) {
+ retval = -ENODEV;
+ goto out2;
+ }
+
+ switch (type) {
+ case FILE_CPULIST:
+ retval = update_cpumask(cs, buffer);
+ break;
+ case FILE_MEMLIST:
+ retval = update_nodemask(cs, buffer);
+ break;
+ case FILE_CPU_EXCLUSIVE:
+ retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer);
+ break;
+ case FILE_MEM_EXCLUSIVE:
+ retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
+ break;
+ case FILE_NOTIFY_ON_RELEASE:
+ retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer);
+ break;
+ case FILE_TASKLIST:
+ retval = attach_task(cs, buffer);
+ break;
+ default:
+ retval = -EINVAL;
+ goto out2;
+ }
+
+ if (retval == 0)
+ retval = nbytes;
+out2:
+ up(&cpuset_sem);
+out1:
+ kfree(buffer);
+ return retval;
+}
+
+static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ ssize_t retval = 0;
+ struct cftype *cft = __d_cft(file->f_dentry);
+ if (!cft)
+ return -ENODEV;
+
+ /* special function ? */
+ if (cft->write)
+ retval = cft->write(file, buf, nbytes, ppos);
+ else
+ retval = cpuset_common_file_write(file, buf, nbytes, ppos);
+
+ return retval;
+}
+
+/*
+ * These ascii lists should be read in a single call, by using a user
+ * buffer large enough to hold the entire map. If read in smaller
+ * chunks, there is no guarantee of atomicity. Since the display format
+ * used, list of ranges of sequential numbers, is variable length,
+ * and since these maps can change value dynamically, one could read
+ * gibberish by doing partial reads while a list was changing.
+ * A single large read to a buffer that crosses a page boundary is
+ * ok, because the result being copied to user land is not recomputed
+ * across a page fault.
+ */
+
+static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
+{
+ cpumask_t mask;
+
+ down(&cpuset_sem);
+ mask = cs->cpus_allowed;
+ up(&cpuset_sem);
+
+ return cpulist_scnprintf(page, PAGE_SIZE, mask);
+}
+
+static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
+{
+ nodemask_t mask;
+
+ down(&cpuset_sem);
+ mask = cs->mems_allowed;
+ up(&cpuset_sem);
+
+ return nodelist_scnprintf(page, PAGE_SIZE, mask);
+}
+
+static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ struct cftype *cft = __d_cft(file->f_dentry);
+ struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
+ cpuset_filetype_t type = cft->private;
+ char *page;
+ ssize_t retval = 0;
+ char *s;
+ char *start;
+ size_t n;
+
+ if (!(page = (char *)__get_free_page(GFP_KERNEL)))
+ return -ENOMEM;
+
+ s = page;
+
+ switch (type) {
+ case FILE_CPULIST:
+ s += cpuset_sprintf_cpulist(s, cs);
+ break;
+ case FILE_MEMLIST:
+ s += cpuset_sprintf_memlist(s, cs);
+ break;
+ case FILE_CPU_EXCLUSIVE:
+ *s++ = is_cpu_exclusive(cs) ? '1' : '0';
+ break;
+ case FILE_MEM_EXCLUSIVE:
+ *s++ = is_mem_exclusive(cs) ? '1' : '0';
+ break;
+ case FILE_NOTIFY_ON_RELEASE:
+ *s++ = notify_on_release(cs) ? '1' : '0';
+ break;
+ default:
+ retval = -EINVAL;
+ goto out;
+ }
+ *s++ = '\n';
+ *s = '\0';
+
+ start = page + *ppos;
+ n = s - start;
+ retval = n - copy_to_user(buf, start, min(n, nbytes));
+ *ppos += retval;
+out:
+ free_page((unsigned long)page);
+ return retval;
+}
+
+static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos)
+{
+ ssize_t retval = 0;
+ struct cftype *cft = __d_cft(file->f_dentry);
+ if (!cft)
+ return -ENODEV;
+
+ /* special function ? */
+ if (cft->read)
+ retval = cft->read(file, buf, nbytes, ppos);
+ else
+ retval = cpuset_common_file_read(file, buf, nbytes, ppos);
+
+ return retval;
+}
+
+static int cpuset_file_open(struct inode *inode, struct file *file)
+{
+ int err;
+ struct cftype *cft;
+
+ err = generic_file_open(inode, file);
+ if (err)
+ return err;
+
+ cft = __d_cft(file->f_dentry);
+ if (!cft)
+ return -ENODEV;
+ if (cft->open)
+ err = cft->open(inode, file);
+ else
+ err = 0;
+
+ return err;
+}
+
+static int cpuset_file_release(struct inode *inode, struct file *file)
+{
+ struct cftype *cft = __d_cft(file->f_dentry);
+ if (cft->release)
+ return cft->release(inode, file);
+ return 0;
+}
+
+static struct file_operations cpuset_file_operations = {
+ .read = cpuset_file_read,
+ .write = cpuset_file_write,
+ .llseek = generic_file_llseek,
+ .open = cpuset_file_open,
+ .release = cpuset_file_release,
+};
+
+static struct inode_operations cpuset_dir_inode_operations = {
+ .lookup = simple_lookup,
+ .mkdir = cpuset_mkdir,
+ .rmdir = cpuset_rmdir,
+};
+
+static int cpuset_create_file(struct dentry *dentry, int mode)
+{
+ struct inode *inode;
+
+ if (!dentry)
+ return -ENOENT;
+ if (dentry->d_inode)
+ return -EEXIST;
+
+ inode = cpuset_new_inode(mode);
+ if (!inode)
+ return -ENOMEM;
+
+ if (S_ISDIR(mode)) {
+ inode->i_op = &cpuset_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+
+ /* start off with i_nlink == 2 (for "." entry) */
+ inode->i_nlink++;
+ } else if (S_ISREG(mode)) {
+ inode->i_size = 0;
+ inode->i_fop = &cpuset_file_operations;
+ }
+
+ d_instantiate(dentry, inode);
+ dget(dentry); /* Extra count - pin the dentry in core */
+ return 0;
+}
+
+/*
+ * cpuset_create_dir - create a directory for an object.
+ * cs: the cpuset we create the directory for.
+ * It must have a valid ->parent field
+ * And we are going to fill its ->dentry field.
+ * name: The name to give to the cpuset directory. Will be copied.
+ * mode: mode to set on new directory.
+ */
+
+static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
+{
+ struct dentry *dentry = NULL;
+ struct dentry *parent;
+ int error = 0;
+
+ parent = cs->parent->dentry;
+ dentry = cpuset_get_dentry(parent, name);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ error = cpuset_create_file(dentry, S_IFDIR | mode);
+ if (!error) {
+ dentry->d_fsdata = cs;
+ parent->d_inode->i_nlink++;
+ cs->dentry = dentry;
+ }
+ dput(dentry);
+
+ return error;
+}
+
+static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
+{
+ struct dentry *dentry;
+ int error;
+
+ down(&dir->d_inode->i_sem);
+ dentry = cpuset_get_dentry(dir, cft->name);
+ if (!IS_ERR(dentry)) {
+ error = cpuset_create_file(dentry, 0644 | S_IFREG);
+ if (!error)
+ dentry->d_fsdata = (void *)cft;
+ dput(dentry);
+ } else
+ error = PTR_ERR(dentry);
+ up(&dir->d_inode->i_sem);
+ return error;
+}
+
+/*
+ * Stuff for reading the 'tasks' file.
+ *
+ * Reading this file can return large amounts of data if a cpuset has
+ * *lots* of attached tasks. So it may need several calls to read(),
+ * but we cannot guarantee that the information we produce is correct
+ * unless we produce it entirely atomically.
+ *
+ * Upon tasks file open(), a struct ctr_struct is allocated, that
+ * will have a pointer to an array (also allocated here). The struct
+ * ctr_struct * is stored in file->private_data. Its resources will
+ * be freed by release() when the file is closed. The array is used
+ * to sprintf the PIDs and then used by read().
+ */
+
+/* cpusets_tasks_read array */
+
+struct ctr_struct {
+ char *buf;
+ int bufsz;
+};
+
+/*
+ * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
+ * Return actual number of pids loaded.
+ */
+static inline int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
+{
+ int n = 0;
+ struct task_struct *g, *p;
+
+ read_lock(&tasklist_lock);
+
+ do_each_thread(g, p) {
+ if (p->cpuset == cs) {
+ pidarray[n++] = p->pid;
+ if (unlikely(n == npids))
+ goto array_full;
+ }
+ } while_each_thread(g, p);
+
+array_full:
+ read_unlock(&tasklist_lock);
+ return n;
+}
+
+static int cmppid(const void *a, const void *b)
+{
+ return *(pid_t *)a - *(pid_t *)b;
+}
+
+/*
+ * Convert array 'a' of 'npids' pid_t's to a string of newline separated
+ * decimal pids in 'buf'. Don't write more than 'sz' chars, but return
+ * count 'cnt' of how many chars would be written if buf were large enough.
+ */
+static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
+{
+ int cnt = 0;
+ int i;
+
+ for (i = 0; i < npids; i++)
+ cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
+ return cnt;
+}
+
+static int cpuset_tasks_open(struct inode *unused, struct file *file)
+{
+ struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
+ struct ctr_struct *ctr;
+ pid_t *pidarray;
+ int npids;
+ char c;
+
+ if (!(file->f_mode & FMODE_READ))
+ return 0;
+
+ ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
+ if (!ctr)
+ goto err0;
+
+ /*
+ * If cpuset gets more users after we read count, we won't have
+ * enough space - tough. This race is indistinguishable to the
+ * caller from the case that the additional cpuset users didn't
+ * show up until sometime later on.
+ */
+ npids = atomic_read(&cs->count);
+ pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
+ if (!pidarray)
+ goto err1;
+
+ npids = pid_array_load(pidarray, npids, cs);
+ sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
+
+ /* Call pid_array_to_buf() twice, first just to get bufsz */
+ ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
+ ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
+ if (!ctr->buf)
+ goto err2;
+ ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
+
+ kfree(pidarray);
+ file->private_data = ctr;
+ return 0;
+
+err2:
+ kfree(pidarray);
+err1:
+ kfree(ctr);
+err0:
+ return -ENOMEM;
+}
+
+static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ struct ctr_struct *ctr = file->private_data;
+
+ if (*ppos + nbytes > ctr->bufsz)
+ nbytes = ctr->bufsz - *ppos;
+ if (copy_to_user(buf, ctr->buf + *ppos, nbytes))
+ return -EFAULT;
+ *ppos += nbytes;
+ return nbytes;
+}
+
+static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
+{
+ struct ctr_struct *ctr;
+
+ if (file->f_mode & FMODE_READ) {
+ ctr = file->private_data;
+ kfree(ctr->buf);
+ kfree(ctr);
+ }
+ return 0;
+}
+
+/*
+ * for the common functions, 'private' gives the type of file
+ */
+
+static struct cftype cft_tasks = {
+ .name = "tasks",
+ .open = cpuset_tasks_open,
+ .read = cpuset_tasks_read,
+ .release = cpuset_tasks_release,
+ .private = FILE_TASKLIST,
+};
+
+static struct cftype cft_cpus = {
+ .name = "cpus",
+ .private = FILE_CPULIST,
+};
+
+static struct cftype cft_mems = {
+ .name = "mems",
+ .private = FILE_MEMLIST,
+};
+
+static struct cftype cft_cpu_exclusive = {
+ .name = "cpu_exclusive",
+ .private = FILE_CPU_EXCLUSIVE,
+};
+
+static struct cftype cft_mem_exclusive = {
+ .name = "mem_exclusive",
+ .private = FILE_MEM_EXCLUSIVE,
+};
+
+static struct cftype cft_notify_on_release = {
+ .name = "notify_on_release",
+ .private = FILE_NOTIFY_ON_RELEASE,
+};
+
+static int cpuset_populate_dir(struct dentry *cs_dentry)
+{
+ int err;
+
+ if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
+ return err;
+ if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
+ return err;
+ if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
+ return err;
+ if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
+ return err;
+ if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
+ return err;
+ if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
+ return err;
+ return 0;
+}
+
+/*
+ * cpuset_create - create a cpuset
+ * parent: cpuset that will be parent of the new cpuset.
+ * name: name of the new cpuset. Will be strcpy'ed.
+ * mode: mode to set on new inode
+ *
+ * Must be called with the semaphore on the parent inode held
+ */
+
+static long cpuset_create(struct cpuset *parent, const char *name, int mode)
+{
+ struct cpuset *cs;
+ int err;
+
+ cs = kmalloc(sizeof(*cs), GFP_KERNEL);
+ if (!cs)
+ return -ENOMEM;
+
+ down(&cpuset_sem);
+ refresh_mems();
+ cs->flags = 0;
+ if (notify_on_release(parent))
+ set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
+ cs->cpus_allowed = CPU_MASK_NONE;
+ cs->mems_allowed = NODE_MASK_NONE;
+ atomic_set(&cs->count, 0);
+ INIT_LIST_HEAD(&cs->sibling);
+ INIT_LIST_HEAD(&cs->children);
+ atomic_inc(&cpuset_mems_generation);
+ cs->mems_generation = atomic_read(&cpuset_mems_generation);
+
+ cs->parent = parent;
+
+ list_add(&cs->sibling, &cs->parent->children);
+
+ err = cpuset_create_dir(cs, name, mode);
+ if (err < 0)
+ goto err;
+
+ /*
+ * Release cpuset_sem before cpuset_populate_dir() because it
+ * will down() this new directory's i_sem and if we race with
+ * another mkdir, we might deadlock.
+ */
+ up(&cpuset_sem);
+
+ err = cpuset_populate_dir(cs->dentry);
+ /* If err < 0, we have a half-filled directory - oh well ;) */
+ return 0;
+err:
+ list_del(&cs->sibling);
+ up(&cpuset_sem);
+ kfree(cs);
+ return err;
+}
+
+static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ struct cpuset *c_parent = dentry->d_parent->d_fsdata;
+
+ /* the vfs holds inode->i_sem already */
+ return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
+}
+
+static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
+{
+ struct cpuset *cs = dentry->d_fsdata;
+ struct dentry *d;
+ struct cpuset *parent;
+
+ /* the vfs holds both inode->i_sem already */
+
+ down(&cpuset_sem);
+ refresh_mems();
+ if (atomic_read(&cs->count) > 0) {
+ up(&cpuset_sem);
+ return -EBUSY;
+ }
+ if (!list_empty(&cs->children)) {
+ up(&cpuset_sem);
+ return -EBUSY;
+ }
+ spin_lock(&cs->dentry->d_lock);
+ parent = cs->parent;
+ set_bit(CS_REMOVED, &cs->flags);
+ list_del(&cs->sibling); /* delete my sibling from parent->children */
+ if (list_empty(&parent->children))
+ check_for_release(parent);
+ d = dget(cs->dentry);
+ cs->dentry = NULL;
+ spin_unlock(&d->d_lock);
+ cpuset_d_remove_dir(d);
+ dput(d);
+ up(&cpuset_sem);
+ return 0;
+}
+
+/**
+ * cpuset_init - initialize cpusets at system boot
+ *
+ * Description: Initialize top_cpuset and the cpuset internal file system,
+ **/
+
+int __init cpuset_init(void)
+{
+ struct dentry *root;
+ int err;
+
+ top_cpuset.cpus_allowed = CPU_MASK_ALL;
+ top_cpuset.mems_allowed = NODE_MASK_ALL;
+
+ atomic_inc(&cpuset_mems_generation);
+ top_cpuset.mems_generation = atomic_read(&cpuset_mems_generation);
+
+ init_task.cpuset = &top_cpuset;
+
+ err = register_filesystem(&cpuset_fs_type);
+ if (err < 0)
+ goto out;
+ cpuset_mount = kern_mount(&cpuset_fs_type);
+ if (IS_ERR(cpuset_mount)) {
+ printk(KERN_ERR "cpuset: could not mount!\n");
+ err = PTR_ERR(cpuset_mount);
+ cpuset_mount = NULL;
+ goto out;
+ }
+ root = cpuset_mount->mnt_sb->s_root;
+ root->d_fsdata = &top_cpuset;
+ root->d_inode->i_nlink++;
+ top_cpuset.dentry = root;
+ root->d_inode->i_op = &cpuset_dir_inode_operations;
+ err = cpuset_populate_dir(root);
+out:
+ return err;
+}
+
+/**
+ * cpuset_init_smp - initialize cpus_allowed
+ *
+ * Description: Finish top cpuset after cpu, node maps are initialized
+ **/
+
+void __init cpuset_init_smp(void)
+{
+ top_cpuset.cpus_allowed = cpu_online_map;
+ top_cpuset.mems_allowed = node_online_map;
+}
+
+/**
+ * cpuset_fork - attach newly forked task to its parents cpuset.
+ * @p: pointer to task_struct of forking parent process.
+ *
+ * Description: By default, on fork, a task inherits its
+ * parents cpuset. The pointer to the shared cpuset is
+ * automatically copied in fork.c by dup_task_struct().
+ * This cpuset_fork() routine need only increment the usage
+ * counter in that cpuset.
+ **/
+
+void cpuset_fork(struct task_struct *tsk)
+{
+ atomic_inc(&tsk->cpuset->count);
+}
+
+/**
+ * cpuset_exit - detach cpuset from exiting task
+ * @tsk: pointer to task_struct of exiting process
+ *
+ * Description: Detach cpuset from @tsk and release it.
+ *
+ * Note that cpusets marked notify_on_release force every task
+ * in them to take the global cpuset_sem semaphore when exiting.
+ * This could impact scaling on very large systems. Be reluctant
+ * to use notify_on_release cpusets where very high task exit
+ * scaling is required on large systems.
+ *
+ * Don't even think about derefencing 'cs' after the cpuset use
+ * count goes to zero, except inside a critical section guarded
+ * by the cpuset_sem semaphore. If you don't hold cpuset_sem,
+ * then a zero cpuset use count is a license to any other task to
+ * nuke the cpuset immediately.
+ *
+ **/
+
+void cpuset_exit(struct task_struct *tsk)
+{
+ struct cpuset *cs;
+
+ task_lock(tsk);
+ cs = tsk->cpuset;
+ tsk->cpuset = NULL;
+ task_unlock(tsk);
+
+ if (notify_on_release(cs)) {
+ down(&cpuset_sem);
+ if (atomic_dec_and_test(&cs->count))
+ check_for_release(cs);
+ up(&cpuset_sem);
+ } else {
+ atomic_dec(&cs->count);
+ }
+}
+
+/**
+ * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
+ * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
+ *
+ * Description: Returns the cpumask_t cpus_allowed of the cpuset
+ * attached to the specified @tsk. Guaranteed to return some non-empty
+ * subset of cpu_online_map, even if this means going outside the
+ * tasks cpuset.
+ **/
+
+cpumask_t cpuset_cpus_allowed(const struct task_struct *tsk)
+{
+ cpumask_t mask;
+
+ down(&cpuset_sem);
+ task_lock((struct task_struct *)tsk);
+ guarantee_online_cpus(tsk->cpuset, &mask);
+ task_unlock((struct task_struct *)tsk);
+ up(&cpuset_sem);
+
+ return mask;
+}
+
+void cpuset_init_current_mems_allowed(void)
+{
+ current->mems_allowed = NODE_MASK_ALL;
+}
+
+/*
+ * If the current tasks cpusets mems_allowed changed behind our backs,
+ * update current->mems_allowed and mems_generation to the new value.
+ * Do not call this routine if in_interrupt().
+ */
+
+void cpuset_update_current_mems_allowed(void)
+{
+ struct cpuset *cs = current->cpuset;
+
+ if (!cs)
+ return; /* task is exiting */
+ if (current->cpuset_mems_generation != cs->mems_generation) {
+ down(&cpuset_sem);
+ refresh_mems();
+ up(&cpuset_sem);
+ }
+}
+
+void cpuset_restrict_to_mems_allowed(unsigned long *nodes)
+{
+ bitmap_and(nodes, nodes, nodes_addr(current->mems_allowed),
+ MAX_NUMNODES);
+}
+
+/*
+ * Are any of the nodes on zonelist zl allowed in current->mems_allowed?
+ */
+int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
+{
+ int i;
+
+ for (i = 0; zl->zones[i]; i++) {
+ int nid = zl->zones[i]->zone_pgdat->node_id;
+
+ if (node_isset(nid, current->mems_allowed))
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Is 'current' valid, and is zone z allowed in current->mems_allowed?
+ */
+int cpuset_zone_allowed(struct zone *z)
+{
+ return in_interrupt() ||
+ node_isset(z->zone_pgdat->node_id, current->mems_allowed);
+}
+
+/*
+ * proc_cpuset_show()
+ * - Print tasks cpuset path into seq_file.
+ * - Used for /proc/<pid>/cpuset.
+ */
+
+static int proc_cpuset_show(struct seq_file *m, void *v)
+{
+ struct cpuset *cs;
+ struct task_struct *tsk;
+ char *buf;
+ int retval = 0;
+
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ tsk = m->private;
+ down(&cpuset_sem);
+ task_lock(tsk);
+ cs = tsk->cpuset;
+ task_unlock(tsk);
+ if (!cs) {
+ retval = -EINVAL;
+ goto out;
+ }
+
+ retval = cpuset_path(cs, buf, PAGE_SIZE);
+ if (retval < 0)
+ goto out;
+ seq_puts(m, buf);
+ seq_putc(m, '\n');
+out:
+ up(&cpuset_sem);
+ kfree(buf);
+ return retval;
+}
+
+static int cpuset_open(struct inode *inode, struct file *file)
+{
+ struct task_struct *tsk = PROC_I(inode)->task;
+ return single_open(file, proc_cpuset_show, tsk);
+}
+
+struct file_operations proc_cpuset_operations = {
+ .open = cpuset_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+/* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
+char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
+{
+ buffer += sprintf(buffer, "Cpus_allowed:\t");
+ buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
+ buffer += sprintf(buffer, "\n");
+ buffer += sprintf(buffer, "Mems_allowed:\t");
+ buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
+ buffer += sprintf(buffer, "\n");
+ return buffer;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff