4 * Processor and Memory placement constraints for sets of tasks.
6 * Copyright (C) 2003 BULL SA.
7 * Copyright (C) 2004-2007 Silicon Graphics, Inc.
8 * Copyright (C) 2006 Google, Inc
10 * Portions derived from Patrick Mochel's sysfs code.
11 * sysfs is Copyright (c) 2001-3 Patrick Mochel
13 * 2003-10-10 Written by Simon Derr.
14 * 2003-10-22 Updates by Stephen Hemminger.
15 * 2004 May-July Rework by Paul Jackson.
16 * 2006 Rework by Paul Menage to use generic cgroups
18 * This file is subject to the terms and conditions of the GNU General Public
19 * License. See the file COPYING in the main directory of the Linux
20 * distribution for more details.
23 #include <linux/cpu.h>
24 #include <linux/cpumask.h>
25 #include <linux/cpuset.h>
26 #include <linux/err.h>
27 #include <linux/errno.h>
28 #include <linux/file.h>
30 #include <linux/init.h>
31 #include <linux/interrupt.h>
32 #include <linux/kernel.h>
33 #include <linux/kmod.h>
34 #include <linux/list.h>
35 #include <linux/mempolicy.h>
37 #include <linux/module.h>
38 #include <linux/mount.h>
39 #include <linux/namei.h>
40 #include <linux/pagemap.h>
41 #include <linux/proc_fs.h>
42 #include <linux/rcupdate.h>
43 #include <linux/sched.h>
44 #include <linux/seq_file.h>
45 #include <linux/security.h>
46 #include <linux/slab.h>
47 #include <linux/spinlock.h>
48 #include <linux/stat.h>
49 #include <linux/string.h>
50 #include <linux/time.h>
51 #include <linux/backing-dev.h>
52 #include <linux/sort.h>
54 #include <asm/uaccess.h>
55 #include <asm/atomic.h>
56 #include <linux/mutex.h>
57 #include <linux/kfifo.h>
58 #include <linux/workqueue.h>
59 #include <linux/cgroup.h>
62 * Tracks how many cpusets are currently defined in system.
63 * When there is only one cpuset (the root cpuset) we can
64 * short circuit some hooks.
66 int number_of_cpusets __read_mostly;
68 /* Retrieve the cpuset from a cgroup */
69 struct cgroup_subsys cpuset_subsys;
72 /* See "Frequency meter" comments, below. */
75 int cnt; /* unprocessed events count */
76 int val; /* most recent output value */
77 time_t time; /* clock (secs) when val computed */
78 spinlock_t lock; /* guards read or write of above */
82 struct cgroup_subsys_state css;
84 unsigned long flags; /* "unsigned long" so bitops work */
85 cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
86 nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */
88 struct cpuset *parent; /* my parent */
91 * Copy of global cpuset_mems_generation as of the most
92 * recent time this cpuset changed its mems_allowed.
96 struct fmeter fmeter; /* memory_pressure filter */
98 /* partition number for rebuild_sched_domains() */
101 /* used for walking a cpuset heirarchy */
102 struct list_head stack_list;
105 /* Retrieve the cpuset for a cgroup */
106 static inline struct cpuset *cgroup_cs(struct cgroup *cont)
108 return container_of(cgroup_subsys_state(cont, cpuset_subsys_id),
112 /* Retrieve the cpuset for a task */
113 static inline struct cpuset *task_cs(struct task_struct *task)
115 return container_of(task_subsys_state(task, cpuset_subsys_id),
118 struct cpuset_hotplug_scanner {
119 struct cgroup_scanner scan;
123 /* bits in struct cpuset flags field */
128 CS_SCHED_LOAD_BALANCE,
133 /* convenient tests for these bits */
134 static inline int is_cpu_exclusive(const struct cpuset *cs)
136 return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
139 static inline int is_mem_exclusive(const struct cpuset *cs)
141 return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
144 static inline int is_sched_load_balance(const struct cpuset *cs)
146 return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
149 static inline int is_memory_migrate(const struct cpuset *cs)
151 return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
154 static inline int is_spread_page(const struct cpuset *cs)
156 return test_bit(CS_SPREAD_PAGE, &cs->flags);
159 static inline int is_spread_slab(const struct cpuset *cs)
161 return test_bit(CS_SPREAD_SLAB, &cs->flags);
165 * Increment this integer everytime any cpuset changes its
166 * mems_allowed value. Users of cpusets can track this generation
167 * number, and avoid having to lock and reload mems_allowed unless
168 * the cpuset they're using changes generation.
170 * A single, global generation is needed because attach_task() could
171 * reattach a task to a different cpuset, which must not have its
172 * generation numbers aliased with those of that tasks previous cpuset.
174 * Generations are needed for mems_allowed because one task cannot
175 * modify anothers memory placement. So we must enable every task,
176 * on every visit to __alloc_pages(), to efficiently check whether
177 * its current->cpuset->mems_allowed has changed, requiring an update
178 * of its current->mems_allowed.
180 * Since cpuset_mems_generation is guarded by manage_mutex,
181 * there is no need to mark it atomic.
183 static int cpuset_mems_generation;
185 static struct cpuset top_cpuset = {
186 .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
187 .cpus_allowed = CPU_MASK_ALL,
188 .mems_allowed = NODE_MASK_ALL,
192 * We have two global cpuset mutexes below. They can nest.
193 * It is ok to first take manage_mutex, then nest callback_mutex. We also
194 * require taking task_lock() when dereferencing a tasks cpuset pointer.
195 * See "The task_lock() exception", at the end of this comment.
197 * A task must hold both mutexes to modify cpusets. If a task
198 * holds manage_mutex, then it blocks others wanting that mutex,
199 * ensuring that it is the only task able to also acquire callback_mutex
200 * and be able to modify cpusets. It can perform various checks on
201 * the cpuset structure first, knowing nothing will change. It can
202 * also allocate memory while just holding manage_mutex. While it is
203 * performing these checks, various callback routines can briefly
204 * acquire callback_mutex to query cpusets. Once it is ready to make
205 * the changes, it takes callback_mutex, blocking everyone else.
207 * Calls to the kernel memory allocator can not be made while holding
208 * callback_mutex, as that would risk double tripping on callback_mutex
209 * from one of the callbacks into the cpuset code from within
212 * If a task is only holding callback_mutex, then it has read-only
215 * The task_struct fields mems_allowed and mems_generation may only
216 * be accessed in the context of that task, so require no locks.
218 * Any task can increment and decrement the count field without lock.
219 * So in general, code holding manage_mutex or callback_mutex can't rely
220 * on the count field not changing. However, if the count goes to
221 * zero, then only attach_task(), which holds both mutexes, can
222 * increment it again. Because a count of zero means that no tasks
223 * are currently attached, therefore there is no way a task attached
224 * to that cpuset can fork (the other way to increment the count).
225 * So code holding manage_mutex or callback_mutex can safely assume that
226 * if the count is zero, it will stay zero. Similarly, if a task
227 * holds manage_mutex or callback_mutex on a cpuset with zero count, it
228 * knows that the cpuset won't be removed, as cpuset_rmdir() needs
229 * both of those mutexes.
231 * The cpuset_common_file_write handler for operations that modify
232 * the cpuset hierarchy holds manage_mutex across the entire operation,
233 * single threading all such cpuset modifications across the system.
235 * The cpuset_common_file_read() handlers only hold callback_mutex across
236 * small pieces of code, such as when reading out possibly multi-word
237 * cpumasks and nodemasks.
239 * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't
240 * (usually) take either mutex. These are the two most performance
241 * critical pieces of code here. The exception occurs on cpuset_exit(),
242 * when a task in a notify_on_release cpuset exits. Then manage_mutex
243 * is taken, and if the cpuset count is zero, a usermode call made
244 * to /sbin/cpuset_release_agent with the name of the cpuset (path
245 * relative to the root of cpuset file system) as the argument.
247 * A cpuset can only be deleted if both its 'count' of using tasks
248 * is zero, and its list of 'children' cpusets is empty. Since all
249 * tasks in the system use _some_ cpuset, and since there is always at
250 * least one task in the system (init), therefore, top_cpuset
251 * always has either children cpusets and/or using tasks. So we don't
252 * need a special hack to ensure that top_cpuset cannot be deleted.
254 * The above "Tale of Two Semaphores" would be complete, but for:
256 * The task_lock() exception
258 * The need for this exception arises from the action of attach_task(),
259 * which overwrites one tasks cpuset pointer with another. It does
260 * so using both mutexes, however there are several performance
261 * critical places that need to reference task->cpuset without the
262 * expense of grabbing a system global mutex. Therefore except as
263 * noted below, when dereferencing or, as in attach_task(), modifying
264 * a tasks cpuset pointer we use task_lock(), which acts on a spinlock
265 * (task->alloc_lock) already in the task_struct routinely used for
268 * P.S. One more locking exception. RCU is used to guard the
269 * update of a tasks cpuset pointer by attach_task() and the
270 * access of task->cpuset->mems_generation via that pointer in
271 * the routine cpuset_update_task_memory_state().
274 static DEFINE_MUTEX(callback_mutex);
276 /* This is ugly, but preserves the userspace API for existing cpuset
277 * users. If someone tries to mount the "cpuset" filesystem, we
278 * silently switch it to mount "cgroup" instead */
279 static int cpuset_get_sb(struct file_system_type *fs_type,
280 int flags, const char *unused_dev_name,
281 void *data, struct vfsmount *mnt)
283 struct file_system_type *cgroup_fs = get_fs_type("cgroup");
288 "release_agent=/sbin/cpuset_release_agent";
289 ret = cgroup_fs->get_sb(cgroup_fs, flags,
290 unused_dev_name, mountopts, mnt);
291 put_filesystem(cgroup_fs);
296 static struct file_system_type cpuset_fs_type = {
298 .get_sb = cpuset_get_sb,
302 * Return in *pmask the portion of a cpusets's cpus_allowed that
303 * are online. If none are online, walk up the cpuset hierarchy
304 * until we find one that does have some online cpus. If we get
305 * all the way to the top and still haven't found any online cpus,
306 * return cpu_online_map. Or if passed a NULL cs from an exit'ing
307 * task, return cpu_online_map.
309 * One way or another, we guarantee to return some non-empty subset
312 * Call with callback_mutex held.
315 static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
317 while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
320 cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
322 *pmask = cpu_online_map;
323 BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
327 * Return in *pmask the portion of a cpusets's mems_allowed that
328 * are online, with memory. If none are online with memory, walk
329 * up the cpuset hierarchy until we find one that does have some
330 * online mems. If we get all the way to the top and still haven't
331 * found any online mems, return node_states[N_HIGH_MEMORY].
333 * One way or another, we guarantee to return some non-empty subset
334 * of node_states[N_HIGH_MEMORY].
336 * Call with callback_mutex held.
339 static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
341 while (cs && !nodes_intersects(cs->mems_allowed,
342 node_states[N_HIGH_MEMORY]))
345 nodes_and(*pmask, cs->mems_allowed,
346 node_states[N_HIGH_MEMORY]);
348 *pmask = node_states[N_HIGH_MEMORY];
349 BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
353 * cpuset_update_task_memory_state - update task memory placement
355 * If the current tasks cpusets mems_allowed changed behind our
356 * backs, update current->mems_allowed, mems_generation and task NUMA
357 * mempolicy to the new value.
359 * Task mempolicy is updated by rebinding it relative to the
360 * current->cpuset if a task has its memory placement changed.
361 * Do not call this routine if in_interrupt().
363 * Call without callback_mutex or task_lock() held. May be
364 * called with or without manage_mutex held. Thanks in part to
365 * 'the_top_cpuset_hack', the tasks cpuset pointer will never
366 * be NULL. This routine also might acquire callback_mutex and
367 * current->mm->mmap_sem during call.
369 * Reading current->cpuset->mems_generation doesn't need task_lock
370 * to guard the current->cpuset derefence, because it is guarded
371 * from concurrent freeing of current->cpuset by attach_task(),
374 * The rcu_dereference() is technically probably not needed,
375 * as I don't actually mind if I see a new cpuset pointer but
376 * an old value of mems_generation. However this really only
377 * matters on alpha systems using cpusets heavily. If I dropped
378 * that rcu_dereference(), it would save them a memory barrier.
379 * For all other arch's, rcu_dereference is a no-op anyway, and for
380 * alpha systems not using cpusets, another planned optimization,
381 * avoiding the rcu critical section for tasks in the root cpuset
382 * which is statically allocated, so can't vanish, will make this
383 * irrelevant. Better to use RCU as intended, than to engage in
384 * some cute trick to save a memory barrier that is impossible to
385 * test, for alpha systems using cpusets heavily, which might not
388 * This routine is needed to update the per-task mems_allowed data,
389 * within the tasks context, when it is trying to allocate memory
390 * (in various mm/mempolicy.c routines) and notices that some other
391 * task has been modifying its cpuset.
394 void cpuset_update_task_memory_state(void)
396 int my_cpusets_mem_gen;
397 struct task_struct *tsk = current;
400 if (task_cs(tsk) == &top_cpuset) {
401 /* Don't need rcu for top_cpuset. It's never freed. */
402 my_cpusets_mem_gen = top_cpuset.mems_generation;
405 my_cpusets_mem_gen = task_cs(current)->mems_generation;
409 if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
410 mutex_lock(&callback_mutex);
412 cs = task_cs(tsk); /* Maybe changed when task not locked */
413 guarantee_online_mems(cs, &tsk->mems_allowed);
414 tsk->cpuset_mems_generation = cs->mems_generation;
415 if (is_spread_page(cs))
416 tsk->flags |= PF_SPREAD_PAGE;
418 tsk->flags &= ~PF_SPREAD_PAGE;
419 if (is_spread_slab(cs))
420 tsk->flags |= PF_SPREAD_SLAB;
422 tsk->flags &= ~PF_SPREAD_SLAB;
424 mutex_unlock(&callback_mutex);
425 mpol_rebind_task(tsk, &tsk->mems_allowed);
430 * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
432 * One cpuset is a subset of another if all its allowed CPUs and
433 * Memory Nodes are a subset of the other, and its exclusive flags
434 * are only set if the other's are set. Call holding manage_mutex.
437 static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
439 return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
440 nodes_subset(p->mems_allowed, q->mems_allowed) &&
441 is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
442 is_mem_exclusive(p) <= is_mem_exclusive(q);
446 * validate_change() - Used to validate that any proposed cpuset change
447 * follows the structural rules for cpusets.
449 * If we replaced the flag and mask values of the current cpuset
450 * (cur) with those values in the trial cpuset (trial), would
451 * our various subset and exclusive rules still be valid? Presumes
454 * 'cur' is the address of an actual, in-use cpuset. Operations
455 * such as list traversal that depend on the actual address of the
456 * cpuset in the list must use cur below, not trial.
458 * 'trial' is the address of bulk structure copy of cur, with
459 * perhaps one or more of the fields cpus_allowed, mems_allowed,
460 * or flags changed to new, trial values.
462 * Return 0 if valid, -errno if not.
465 static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
468 struct cpuset *c, *par;
470 /* Each of our child cpusets must be a subset of us */
471 list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
472 if (!is_cpuset_subset(cgroup_cs(cont), trial))
476 /* Remaining checks don't apply to root cpuset */
477 if (cur == &top_cpuset)
482 /* We must be a subset of our parent cpuset */
483 if (!is_cpuset_subset(trial, par))
486 /* If either I or some sibling (!= me) is exclusive, we can't overlap */
487 list_for_each_entry(cont, &par->css.cgroup->children, sibling) {
489 if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
491 cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
493 if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
495 nodes_intersects(trial->mems_allowed, c->mems_allowed))
499 /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */
500 if (cgroup_task_count(cur->css.cgroup)) {
501 if (cpus_empty(trial->cpus_allowed) ||
502 nodes_empty(trial->mems_allowed)) {
511 * Helper routine for rebuild_sched_domains().
512 * Do cpusets a, b have overlapping cpus_allowed masks?
515 static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
517 return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
521 * rebuild_sched_domains()
523 * If the flag 'sched_load_balance' of any cpuset with non-empty
524 * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
525 * which has that flag enabled, or if any cpuset with a non-empty
526 * 'cpus' is removed, then call this routine to rebuild the
527 * scheduler's dynamic sched domains.
529 * This routine builds a partial partition of the systems CPUs
530 * (the set of non-overlappping cpumask_t's in the array 'part'
531 * below), and passes that partial partition to the kernel/sched.c
532 * partition_sched_domains() routine, which will rebuild the
533 * schedulers load balancing domains (sched domains) as specified
534 * by that partial partition. A 'partial partition' is a set of
535 * non-overlapping subsets whose union is a subset of that set.
537 * See "What is sched_load_balance" in Documentation/cpusets.txt
538 * for a background explanation of this.
540 * Does not return errors, on the theory that the callers of this
541 * routine would rather not worry about failures to rebuild sched
542 * domains when operating in the severe memory shortage situations
543 * that could cause allocation failures below.
545 * Call with cgroup_mutex held. May take callback_mutex during
546 * call due to the kfifo_alloc() and kmalloc() calls. May nest
547 * a call to the get_online_cpus()/put_online_cpus() pair.
548 * Must not be called holding callback_mutex, because we must not
549 * call get_online_cpus() while holding callback_mutex. Elsewhere
550 * the kernel nests callback_mutex inside get_online_cpus() calls.
551 * So the reverse nesting would risk an ABBA deadlock.
553 * The three key local variables below are:
554 * q - a kfifo queue of cpuset pointers, used to implement a
555 * top-down scan of all cpusets. This scan loads a pointer
556 * to each cpuset marked is_sched_load_balance into the
557 * array 'csa'. For our purposes, rebuilding the schedulers
558 * sched domains, we can ignore !is_sched_load_balance cpusets.
559 * csa - (for CpuSet Array) Array of pointers to all the cpusets
560 * that need to be load balanced, for convenient iterative
561 * access by the subsequent code that finds the best partition,
562 * i.e the set of domains (subsets) of CPUs such that the
563 * cpus_allowed of every cpuset marked is_sched_load_balance
564 * is a subset of one of these domains, while there are as
565 * many such domains as possible, each as small as possible.
566 * doms - Conversion of 'csa' to an array of cpumasks, for passing to
567 * the kernel/sched.c routine partition_sched_domains() in a
568 * convenient format, that can be easily compared to the prior
569 * value to determine what partition elements (sched domains)
570 * were changed (added or removed.)
572 * Finding the best partition (set of domains):
573 * The triple nested loops below over i, j, k scan over the
574 * load balanced cpusets (using the array of cpuset pointers in
575 * csa[]) looking for pairs of cpusets that have overlapping
576 * cpus_allowed, but which don't have the same 'pn' partition
577 * number and gives them in the same partition number. It keeps
578 * looping on the 'restart' label until it can no longer find
581 * The union of the cpus_allowed masks from the set of
582 * all cpusets having the same 'pn' value then form the one
583 * element of the partition (one sched domain) to be passed to
584 * partition_sched_domains().
587 static void rebuild_sched_domains(void)
589 struct kfifo *q; /* queue of cpusets to be scanned */
590 struct cpuset *cp; /* scans q */
591 struct cpuset **csa; /* array of all cpuset ptrs */
592 int csn; /* how many cpuset ptrs in csa so far */
593 int i, j, k; /* indices for partition finding loops */
594 cpumask_t *doms; /* resulting partition; i.e. sched domains */
595 int ndoms; /* number of sched domains in result */
596 int nslot; /* next empty doms[] cpumask_t slot */
602 /* Special case for the 99% of systems with one, full, sched domain */
603 if (is_sched_load_balance(&top_cpuset)) {
605 doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
608 *doms = top_cpuset.cpus_allowed;
612 q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL);
615 csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
621 __kfifo_put(q, (void *)&cp, sizeof(cp));
622 while (__kfifo_get(q, (void *)&cp, sizeof(cp))) {
624 struct cpuset *child; /* scans child cpusets of cp */
625 if (is_sched_load_balance(cp))
627 list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
628 child = cgroup_cs(cont);
629 __kfifo_put(q, (void *)&child, sizeof(cp));
633 for (i = 0; i < csn; i++)
638 /* Find the best partition (set of sched domains) */
639 for (i = 0; i < csn; i++) {
640 struct cpuset *a = csa[i];
643 for (j = 0; j < csn; j++) {
644 struct cpuset *b = csa[j];
647 if (apn != bpn && cpusets_overlap(a, b)) {
648 for (k = 0; k < csn; k++) {
649 struct cpuset *c = csa[k];
654 ndoms--; /* one less element */
660 /* Convert <csn, csa> to <ndoms, doms> */
661 doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
665 for (nslot = 0, i = 0; i < csn; i++) {
666 struct cpuset *a = csa[i];
670 cpumask_t *dp = doms + nslot;
672 if (nslot == ndoms) {
673 static int warnings = 10;
676 "rebuild_sched_domains confused:"
677 " nslot %d, ndoms %d, csn %d, i %d,"
679 nslot, ndoms, csn, i, apn);
686 for (j = i; j < csn; j++) {
687 struct cpuset *b = csa[j];
690 cpus_or(*dp, *dp, b->cpus_allowed);
697 BUG_ON(nslot != ndoms);
700 /* Have scheduler rebuild sched domains */
702 partition_sched_domains(ndoms, doms);
709 /* Don't kfree(doms) -- partition_sched_domains() does that. */
712 static inline int started_after_time(struct task_struct *t1,
713 struct timespec *time,
714 struct task_struct *t2)
716 int start_diff = timespec_compare(&t1->start_time, time);
717 if (start_diff > 0) {
719 } else if (start_diff < 0) {
723 * Arbitrarily, if two processes started at the same
724 * time, we'll say that the lower pointer value
725 * started first. Note that t2 may have exited by now
726 * so this may not be a valid pointer any longer, but
727 * that's fine - it still serves to distinguish
728 * between two tasks started (effectively)
735 static inline int started_after(void *p1, void *p2)
737 struct task_struct *t1 = p1;
738 struct task_struct *t2 = p2;
739 return started_after_time(t1, &t2->start_time, t2);
743 * cpuset_test_cpumask - test a task's cpus_allowed versus its cpuset's
745 * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
747 * Call with manage_mutex held. May take callback_mutex during call.
748 * Called for each task in a cgroup by cgroup_scan_tasks().
749 * Return nonzero if this tasks's cpus_allowed mask should be changed (in other
750 * words, if its mask is not equal to its cpuset's mask).
752 int cpuset_test_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
754 return !cpus_equal(tsk->cpus_allowed,
755 (cgroup_cs(scan->cg))->cpus_allowed);
759 * cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
761 * @scan: struct cgroup_scanner containing the cgroup of the task
763 * Called by cgroup_scan_tasks() for each task in a cgroup whose
764 * cpus_allowed mask needs to be changed.
766 * We don't need to re-check for the cgroup/cpuset membership, since we're
767 * holding cgroup_lock() at this point.
769 void cpuset_change_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
771 set_cpus_allowed(tsk, (cgroup_cs(scan->cg))->cpus_allowed);
775 * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
776 * @cs: the cpuset to consider
777 * @buf: buffer of cpu numbers written to this cpuset
779 static int update_cpumask(struct cpuset *cs, char *buf)
781 struct cpuset trialcs;
782 struct cgroup_scanner scan;
783 struct ptr_heap heap;
785 int is_load_balanced;
787 /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
788 if (cs == &top_cpuset)
794 * An empty cpus_allowed is ok if there are no tasks in the cpuset.
795 * Since cpulist_parse() fails on an empty mask, we special case
796 * that parsing. The validate_change() call ensures that cpusets
797 * with tasks have cpus.
801 cpus_clear(trialcs.cpus_allowed);
803 retval = cpulist_parse(buf, trialcs.cpus_allowed);
807 cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
808 retval = validate_change(cs, &trialcs);
812 /* Nothing to do if the cpus didn't change */
813 if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))
816 retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);
820 is_load_balanced = is_sched_load_balance(&trialcs);
822 mutex_lock(&callback_mutex);
823 cs->cpus_allowed = trialcs.cpus_allowed;
824 mutex_unlock(&callback_mutex);
827 * Scan tasks in the cpuset, and update the cpumasks of any
828 * that need an update.
830 scan.cg = cs->css.cgroup;
831 scan.test_task = cpuset_test_cpumask;
832 scan.process_task = cpuset_change_cpumask;
834 cgroup_scan_tasks(&scan);
837 if (is_load_balanced)
838 rebuild_sched_domains();
845 * Migrate memory region from one set of nodes to another.
847 * Temporarilly set tasks mems_allowed to target nodes of migration,
848 * so that the migration code can allocate pages on these nodes.
850 * Call holding manage_mutex, so our current->cpuset won't change
851 * during this call, as manage_mutex holds off any attach_task()
852 * calls. Therefore we don't need to take task_lock around the
853 * call to guarantee_online_mems(), as we know no one is changing
856 * Hold callback_mutex around the two modifications of our tasks
857 * mems_allowed to synchronize with cpuset_mems_allowed().
859 * While the mm_struct we are migrating is typically from some
860 * other task, the task_struct mems_allowed that we are hacking
861 * is for our current task, which must allocate new pages for that
862 * migrating memory region.
864 * We call cpuset_update_task_memory_state() before hacking
865 * our tasks mems_allowed, so that we are assured of being in
866 * sync with our tasks cpuset, and in particular, callbacks to
867 * cpuset_update_task_memory_state() from nested page allocations
868 * won't see any mismatch of our cpuset and task mems_generation
869 * values, so won't overwrite our hacked tasks mems_allowed
873 static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
874 const nodemask_t *to)
876 struct task_struct *tsk = current;
878 cpuset_update_task_memory_state();
880 mutex_lock(&callback_mutex);
881 tsk->mems_allowed = *to;
882 mutex_unlock(&callback_mutex);
884 do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
886 mutex_lock(&callback_mutex);
887 guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
888 mutex_unlock(&callback_mutex);
892 * Handle user request to change the 'mems' memory placement
893 * of a cpuset. Needs to validate the request, update the
894 * cpusets mems_allowed and mems_generation, and for each
895 * task in the cpuset, rebind any vma mempolicies and if
896 * the cpuset is marked 'memory_migrate', migrate the tasks
897 * pages to the new memory.
899 * Call with manage_mutex held. May take callback_mutex during call.
900 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
901 * lock each such tasks mm->mmap_sem, scan its vma's and rebind
902 * their mempolicies to the cpusets new mems_allowed.
905 static void *cpuset_being_rebound;
907 static int update_nodemask(struct cpuset *cs, char *buf)
909 struct cpuset trialcs;
911 struct task_struct *p;
912 struct mm_struct **mmarray;
917 struct cgroup_iter it;
920 * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
923 if (cs == &top_cpuset)
929 * An empty mems_allowed is ok iff there are no tasks in the cpuset.
930 * Since nodelist_parse() fails on an empty mask, we special case
931 * that parsing. The validate_change() call ensures that cpusets
932 * with tasks have memory.
936 nodes_clear(trialcs.mems_allowed);
938 retval = nodelist_parse(buf, trialcs.mems_allowed);
942 nodes_and(trialcs.mems_allowed, trialcs.mems_allowed,
943 node_states[N_HIGH_MEMORY]);
944 oldmem = cs->mems_allowed;
945 if (nodes_equal(oldmem, trialcs.mems_allowed)) {
946 retval = 0; /* Too easy - nothing to do */
949 retval = validate_change(cs, &trialcs);
953 mutex_lock(&callback_mutex);
954 cs->mems_allowed = trialcs.mems_allowed;
955 cs->mems_generation = cpuset_mems_generation++;
956 mutex_unlock(&callback_mutex);
958 cpuset_being_rebound = cs; /* causes mpol_copy() rebind */
960 fudge = 10; /* spare mmarray[] slots */
961 fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */
965 * Allocate mmarray[] to hold mm reference for each task
966 * in cpuset cs. Can't kmalloc GFP_KERNEL while holding
967 * tasklist_lock. We could use GFP_ATOMIC, but with a
968 * few more lines of code, we can retry until we get a big
969 * enough mmarray[] w/o using GFP_ATOMIC.
972 ntasks = cgroup_task_count(cs->css.cgroup); /* guess */
974 mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
977 read_lock(&tasklist_lock); /* block fork */
978 if (cgroup_task_count(cs->css.cgroup) <= ntasks)
979 break; /* got enough */
980 read_unlock(&tasklist_lock); /* try again */
986 /* Load up mmarray[] with mm reference for each task in cpuset. */
987 cgroup_iter_start(cs->css.cgroup, &it);
988 while ((p = cgroup_iter_next(cs->css.cgroup, &it))) {
989 struct mm_struct *mm;
993 "Cpuset mempolicy rebind incomplete.\n");
1001 cgroup_iter_end(cs->css.cgroup, &it);
1002 read_unlock(&tasklist_lock);
1005 * Now that we've dropped the tasklist spinlock, we can
1006 * rebind the vma mempolicies of each mm in mmarray[] to their
1007 * new cpuset, and release that mm. The mpol_rebind_mm()
1008 * call takes mmap_sem, which we couldn't take while holding
1009 * tasklist_lock. Forks can happen again now - the mpol_copy()
1010 * cpuset_being_rebound check will catch such forks, and rebind
1011 * their vma mempolicies too. Because we still hold the global
1012 * cpuset manage_mutex, we know that no other rebind effort will
1013 * be contending for the global variable cpuset_being_rebound.
1014 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
1015 * is idempotent. Also migrate pages in each mm to new nodes.
1017 migrate = is_memory_migrate(cs);
1018 for (i = 0; i < n; i++) {
1019 struct mm_struct *mm = mmarray[i];
1021 mpol_rebind_mm(mm, &cs->mems_allowed);
1023 cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
1027 /* We're done rebinding vma's to this cpusets new mems_allowed. */
1029 cpuset_being_rebound = NULL;
1035 int current_cpuset_is_being_rebound(void)
1037 return task_cs(current) == cpuset_being_rebound;
1041 * Call with manage_mutex held.
1044 static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
1046 if (simple_strtoul(buf, NULL, 10) != 0)
1047 cpuset_memory_pressure_enabled = 1;
1049 cpuset_memory_pressure_enabled = 0;
1054 * update_flag - read a 0 or a 1 in a file and update associated flag
1055 * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
1056 * CS_SCHED_LOAD_BALANCE,
1057 * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE,
1058 * CS_SPREAD_PAGE, CS_SPREAD_SLAB)
1059 * cs: the cpuset to update
1060 * buf: the buffer where we read the 0 or 1
1062 * Call with manage_mutex held.
1065 static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
1068 struct cpuset trialcs;
1070 int cpus_nonempty, balance_flag_changed;
1072 turning_on = (simple_strtoul(buf, NULL, 10) != 0);
1076 set_bit(bit, &trialcs.flags);
1078 clear_bit(bit, &trialcs.flags);
1080 err = validate_change(cs, &trialcs);
1084 cpus_nonempty = !cpus_empty(trialcs.cpus_allowed);
1085 balance_flag_changed = (is_sched_load_balance(cs) !=
1086 is_sched_load_balance(&trialcs));
1088 mutex_lock(&callback_mutex);
1089 cs->flags = trialcs.flags;
1090 mutex_unlock(&callback_mutex);
1092 if (cpus_nonempty && balance_flag_changed)
1093 rebuild_sched_domains();
1099 * Frequency meter - How fast is some event occurring?
1101 * These routines manage a digitally filtered, constant time based,
1102 * event frequency meter. There are four routines:
1103 * fmeter_init() - initialize a frequency meter.
1104 * fmeter_markevent() - called each time the event happens.
1105 * fmeter_getrate() - returns the recent rate of such events.
1106 * fmeter_update() - internal routine used to update fmeter.
1108 * A common data structure is passed to each of these routines,
1109 * which is used to keep track of the state required to manage the
1110 * frequency meter and its digital filter.
1112 * The filter works on the number of events marked per unit time.
1113 * The filter is single-pole low-pass recursive (IIR). The time unit
1114 * is 1 second. Arithmetic is done using 32-bit integers scaled to
1115 * simulate 3 decimal digits of precision (multiplied by 1000).
1117 * With an FM_COEF of 933, and a time base of 1 second, the filter
1118 * has a half-life of 10 seconds, meaning that if the events quit
1119 * happening, then the rate returned from the fmeter_getrate()
1120 * will be cut in half each 10 seconds, until it converges to zero.
1122 * It is not worth doing a real infinitely recursive filter. If more
1123 * than FM_MAXTICKS ticks have elapsed since the last filter event,
1124 * just compute FM_MAXTICKS ticks worth, by which point the level
1127 * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
1128 * arithmetic overflow in the fmeter_update() routine.
1130 * Given the simple 32 bit integer arithmetic used, this meter works
1131 * best for reporting rates between one per millisecond (msec) and
1132 * one per 32 (approx) seconds. At constant rates faster than one
1133 * per msec it maxes out at values just under 1,000,000. At constant
1134 * rates between one per msec, and one per second it will stabilize
1135 * to a value N*1000, where N is the rate of events per second.
1136 * At constant rates between one per second and one per 32 seconds,
1137 * it will be choppy, moving up on the seconds that have an event,
1138 * and then decaying until the next event. At rates slower than
1139 * about one in 32 seconds, it decays all the way back to zero between
1143 #define FM_COEF 933 /* coefficient for half-life of 10 secs */
1144 #define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */
1145 #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
1146 #define FM_SCALE 1000 /* faux fixed point scale */
1148 /* Initialize a frequency meter */
1149 static void fmeter_init(struct fmeter *fmp)
1154 spin_lock_init(&fmp->lock);
1157 /* Internal meter update - process cnt events and update value */
1158 static void fmeter_update(struct fmeter *fmp)
1160 time_t now = get_seconds();
1161 time_t ticks = now - fmp->time;
1166 ticks = min(FM_MAXTICKS, ticks);
1168 fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
1171 fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
1175 /* Process any previous ticks, then bump cnt by one (times scale). */
1176 static void fmeter_markevent(struct fmeter *fmp)
1178 spin_lock(&fmp->lock);
1180 fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
1181 spin_unlock(&fmp->lock);
1184 /* Process any previous ticks, then return current value. */
1185 static int fmeter_getrate(struct fmeter *fmp)
1189 spin_lock(&fmp->lock);
1192 spin_unlock(&fmp->lock);
1196 static int cpuset_can_attach(struct cgroup_subsys *ss,
1197 struct cgroup *cont, struct task_struct *tsk)
1199 struct cpuset *cs = cgroup_cs(cont);
1201 if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
1204 return security_task_setscheduler(tsk, 0, NULL);
1207 static void cpuset_attach(struct cgroup_subsys *ss,
1208 struct cgroup *cont, struct cgroup *oldcont,
1209 struct task_struct *tsk)
1212 nodemask_t from, to;
1213 struct mm_struct *mm;
1214 struct cpuset *cs = cgroup_cs(cont);
1215 struct cpuset *oldcs = cgroup_cs(oldcont);
1217 mutex_lock(&callback_mutex);
1218 guarantee_online_cpus(cs, &cpus);
1219 set_cpus_allowed(tsk, cpus);
1220 mutex_unlock(&callback_mutex);
1222 from = oldcs->mems_allowed;
1223 to = cs->mems_allowed;
1224 mm = get_task_mm(tsk);
1226 mpol_rebind_mm(mm, &to);
1227 if (is_memory_migrate(cs))
1228 cpuset_migrate_mm(mm, &from, &to);
1234 /* The various types of files and directories in a cpuset file system */
1237 FILE_MEMORY_MIGRATE,
1242 FILE_SCHED_LOAD_BALANCE,
1243 FILE_MEMORY_PRESSURE_ENABLED,
1244 FILE_MEMORY_PRESSURE,
1247 } cpuset_filetype_t;
1249 static ssize_t cpuset_common_file_write(struct cgroup *cont,
1252 const char __user *userbuf,
1253 size_t nbytes, loff_t *unused_ppos)
1255 struct cpuset *cs = cgroup_cs(cont);
1256 cpuset_filetype_t type = cft->private;
1260 /* Crude upper limit on largest legitimate cpulist user might write. */
1261 if (nbytes > 100U + 6 * max(NR_CPUS, MAX_NUMNODES))
1264 /* +1 for nul-terminator */
1265 if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0)
1268 if (copy_from_user(buffer, userbuf, nbytes)) {
1272 buffer[nbytes] = 0; /* nul-terminate */
1276 if (cgroup_is_removed(cont)) {
1283 retval = update_cpumask(cs, buffer);
1286 retval = update_nodemask(cs, buffer);
1288 case FILE_CPU_EXCLUSIVE:
1289 retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer);
1291 case FILE_MEM_EXCLUSIVE:
1292 retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
1294 case FILE_SCHED_LOAD_BALANCE:
1295 retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer);
1297 case FILE_MEMORY_MIGRATE:
1298 retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
1300 case FILE_MEMORY_PRESSURE_ENABLED:
1301 retval = update_memory_pressure_enabled(cs, buffer);
1303 case FILE_MEMORY_PRESSURE:
1306 case FILE_SPREAD_PAGE:
1307 retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
1308 cs->mems_generation = cpuset_mems_generation++;
1310 case FILE_SPREAD_SLAB:
1311 retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
1312 cs->mems_generation = cpuset_mems_generation++;
1329 * These ascii lists should be read in a single call, by using a user
1330 * buffer large enough to hold the entire map. If read in smaller
1331 * chunks, there is no guarantee of atomicity. Since the display format
1332 * used, list of ranges of sequential numbers, is variable length,
1333 * and since these maps can change value dynamically, one could read
1334 * gibberish by doing partial reads while a list was changing.
1335 * A single large read to a buffer that crosses a page boundary is
1336 * ok, because the result being copied to user land is not recomputed
1337 * across a page fault.
1340 static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
1344 mutex_lock(&callback_mutex);
1345 mask = cs->cpus_allowed;
1346 mutex_unlock(&callback_mutex);
1348 return cpulist_scnprintf(page, PAGE_SIZE, mask);
1351 static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
1355 mutex_lock(&callback_mutex);
1356 mask = cs->mems_allowed;
1357 mutex_unlock(&callback_mutex);
1359 return nodelist_scnprintf(page, PAGE_SIZE, mask);
1362 static ssize_t cpuset_common_file_read(struct cgroup *cont,
1366 size_t nbytes, loff_t *ppos)
1368 struct cpuset *cs = cgroup_cs(cont);
1369 cpuset_filetype_t type = cft->private;
1374 if (!(page = (char *)__get_free_page(GFP_TEMPORARY)))
1381 s += cpuset_sprintf_cpulist(s, cs);
1384 s += cpuset_sprintf_memlist(s, cs);
1386 case FILE_CPU_EXCLUSIVE:
1387 *s++ = is_cpu_exclusive(cs) ? '1' : '0';
1389 case FILE_MEM_EXCLUSIVE:
1390 *s++ = is_mem_exclusive(cs) ? '1' : '0';
1392 case FILE_SCHED_LOAD_BALANCE:
1393 *s++ = is_sched_load_balance(cs) ? '1' : '0';
1395 case FILE_MEMORY_MIGRATE:
1396 *s++ = is_memory_migrate(cs) ? '1' : '0';
1398 case FILE_MEMORY_PRESSURE_ENABLED:
1399 *s++ = cpuset_memory_pressure_enabled ? '1' : '0';
1401 case FILE_MEMORY_PRESSURE:
1402 s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
1404 case FILE_SPREAD_PAGE:
1405 *s++ = is_spread_page(cs) ? '1' : '0';
1407 case FILE_SPREAD_SLAB:
1408 *s++ = is_spread_slab(cs) ? '1' : '0';
1416 retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
1418 free_page((unsigned long)page);
1427 * for the common functions, 'private' gives the type of file
1430 static struct cftype cft_cpus = {
1432 .read = cpuset_common_file_read,
1433 .write = cpuset_common_file_write,
1434 .private = FILE_CPULIST,
1437 static struct cftype cft_mems = {
1439 .read = cpuset_common_file_read,
1440 .write = cpuset_common_file_write,
1441 .private = FILE_MEMLIST,
1444 static struct cftype cft_cpu_exclusive = {
1445 .name = "cpu_exclusive",
1446 .read = cpuset_common_file_read,
1447 .write = cpuset_common_file_write,
1448 .private = FILE_CPU_EXCLUSIVE,
1451 static struct cftype cft_mem_exclusive = {
1452 .name = "mem_exclusive",
1453 .read = cpuset_common_file_read,
1454 .write = cpuset_common_file_write,
1455 .private = FILE_MEM_EXCLUSIVE,
1458 static struct cftype cft_sched_load_balance = {
1459 .name = "sched_load_balance",
1460 .read = cpuset_common_file_read,
1461 .write = cpuset_common_file_write,
1462 .private = FILE_SCHED_LOAD_BALANCE,
1465 static struct cftype cft_memory_migrate = {
1466 .name = "memory_migrate",
1467 .read = cpuset_common_file_read,
1468 .write = cpuset_common_file_write,
1469 .private = FILE_MEMORY_MIGRATE,
1472 static struct cftype cft_memory_pressure_enabled = {
1473 .name = "memory_pressure_enabled",
1474 .read = cpuset_common_file_read,
1475 .write = cpuset_common_file_write,
1476 .private = FILE_MEMORY_PRESSURE_ENABLED,
1479 static struct cftype cft_memory_pressure = {
1480 .name = "memory_pressure",
1481 .read = cpuset_common_file_read,
1482 .write = cpuset_common_file_write,
1483 .private = FILE_MEMORY_PRESSURE,
1486 static struct cftype cft_spread_page = {
1487 .name = "memory_spread_page",
1488 .read = cpuset_common_file_read,
1489 .write = cpuset_common_file_write,
1490 .private = FILE_SPREAD_PAGE,
1493 static struct cftype cft_spread_slab = {
1494 .name = "memory_spread_slab",
1495 .read = cpuset_common_file_read,
1496 .write = cpuset_common_file_write,
1497 .private = FILE_SPREAD_SLAB,
1500 static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
1504 if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0)
1506 if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0)
1508 if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0)
1510 if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0)
1512 if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0)
1514 if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0)
1516 if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0)
1518 if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0)
1520 if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0)
1522 /* memory_pressure_enabled is in root cpuset only */
1523 if (err == 0 && !cont->parent)
1524 err = cgroup_add_file(cont, ss,
1525 &cft_memory_pressure_enabled);
1530 * post_clone() is called at the end of cgroup_clone().
1531 * 'cgroup' was just created automatically as a result of
1532 * a cgroup_clone(), and the current task is about to
1533 * be moved into 'cgroup'.
1535 * Currently we refuse to set up the cgroup - thereby
1536 * refusing the task to be entered, and as a result refusing
1537 * the sys_unshare() or clone() which initiated it - if any
1538 * sibling cpusets have exclusive cpus or mem.
1540 * If this becomes a problem for some users who wish to
1541 * allow that scenario, then cpuset_post_clone() could be
1542 * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
1543 * (and likewise for mems) to the new cgroup.
1545 static void cpuset_post_clone(struct cgroup_subsys *ss,
1546 struct cgroup *cgroup)
1548 struct cgroup *parent, *child;
1549 struct cpuset *cs, *parent_cs;
1551 parent = cgroup->parent;
1552 list_for_each_entry(child, &parent->children, sibling) {
1553 cs = cgroup_cs(child);
1554 if (is_mem_exclusive(cs) || is_cpu_exclusive(cs))
1557 cs = cgroup_cs(cgroup);
1558 parent_cs = cgroup_cs(parent);
1560 cs->mems_allowed = parent_cs->mems_allowed;
1561 cs->cpus_allowed = parent_cs->cpus_allowed;
1566 * cpuset_create - create a cpuset
1567 * parent: cpuset that will be parent of the new cpuset.
1568 * name: name of the new cpuset. Will be strcpy'ed.
1569 * mode: mode to set on new inode
1571 * Must be called with the mutex on the parent inode held
1574 static struct cgroup_subsys_state *cpuset_create(
1575 struct cgroup_subsys *ss,
1576 struct cgroup *cont)
1579 struct cpuset *parent;
1581 if (!cont->parent) {
1582 /* This is early initialization for the top cgroup */
1583 top_cpuset.mems_generation = cpuset_mems_generation++;
1584 return &top_cpuset.css;
1586 parent = cgroup_cs(cont->parent);
1587 cs = kmalloc(sizeof(*cs), GFP_KERNEL);
1589 return ERR_PTR(-ENOMEM);
1591 cpuset_update_task_memory_state();
1593 if (is_spread_page(parent))
1594 set_bit(CS_SPREAD_PAGE, &cs->flags);
1595 if (is_spread_slab(parent))
1596 set_bit(CS_SPREAD_SLAB, &cs->flags);
1597 set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
1598 cs->cpus_allowed = CPU_MASK_NONE;
1599 cs->mems_allowed = NODE_MASK_NONE;
1600 cs->mems_generation = cpuset_mems_generation++;
1601 fmeter_init(&cs->fmeter);
1603 cs->parent = parent;
1604 number_of_cpusets++;
1609 * Locking note on the strange update_flag() call below:
1611 * If the cpuset being removed has its flag 'sched_load_balance'
1612 * enabled, then simulate turning sched_load_balance off, which
1613 * will call rebuild_sched_domains(). The get_online_cpus()
1614 * call in rebuild_sched_domains() must not be made while holding
1615 * callback_mutex. Elsewhere the kernel nests callback_mutex inside
1616 * get_online_cpus() calls. So the reverse nesting would risk an
1620 static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
1622 struct cpuset *cs = cgroup_cs(cont);
1624 cpuset_update_task_memory_state();
1626 if (is_sched_load_balance(cs))
1627 update_flag(CS_SCHED_LOAD_BALANCE, cs, "0");
1629 number_of_cpusets--;
1633 struct cgroup_subsys cpuset_subsys = {
1635 .create = cpuset_create,
1636 .destroy = cpuset_destroy,
1637 .can_attach = cpuset_can_attach,
1638 .attach = cpuset_attach,
1639 .populate = cpuset_populate,
1640 .post_clone = cpuset_post_clone,
1641 .subsys_id = cpuset_subsys_id,
1646 * cpuset_init_early - just enough so that the calls to
1647 * cpuset_update_task_memory_state() in early init code
1651 int __init cpuset_init_early(void)
1653 top_cpuset.mems_generation = cpuset_mems_generation++;
1659 * cpuset_init - initialize cpusets at system boot
1661 * Description: Initialize top_cpuset and the cpuset internal file system,
1664 int __init cpuset_init(void)
1668 top_cpuset.cpus_allowed = CPU_MASK_ALL;
1669 top_cpuset.mems_allowed = NODE_MASK_ALL;
1671 fmeter_init(&top_cpuset.fmeter);
1672 top_cpuset.mems_generation = cpuset_mems_generation++;
1673 set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
1675 err = register_filesystem(&cpuset_fs_type);
1679 number_of_cpusets = 1;
1684 * cpuset_do_move_task - move a given task to another cpuset
1685 * @tsk: pointer to task_struct the task to move
1686 * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
1688 * Called by cgroup_scan_tasks() for each task in a cgroup.
1689 * Return nonzero to stop the walk through the tasks.
1691 void cpuset_do_move_task(struct task_struct *tsk, struct cgroup_scanner *scan)
1693 struct cpuset_hotplug_scanner *chsp;
1695 chsp = container_of(scan, struct cpuset_hotplug_scanner, scan);
1696 cgroup_attach_task(chsp->to, tsk);
1700 * move_member_tasks_to_cpuset - move tasks from one cpuset to another
1701 * @from: cpuset in which the tasks currently reside
1702 * @to: cpuset to which the tasks will be moved
1704 * Called with manage_sem held
1705 * callback_mutex must not be held, as attach_task() will take it.
1707 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
1708 * calling callback functions for each.
1710 static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
1712 struct cpuset_hotplug_scanner scan;
1714 scan.scan.cg = from->css.cgroup;
1715 scan.scan.test_task = NULL; /* select all tasks in cgroup */
1716 scan.scan.process_task = cpuset_do_move_task;
1717 scan.scan.heap = NULL;
1718 scan.to = to->css.cgroup;
1720 if (cgroup_scan_tasks((struct cgroup_scanner *)&scan))
1721 printk(KERN_ERR "move_member_tasks_to_cpuset: "
1722 "cgroup_scan_tasks failed\n");
1726 * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
1727 * or memory nodes, we need to walk over the cpuset hierarchy,
1728 * removing that CPU or node from all cpusets. If this removes the
1729 * last CPU or node from a cpuset, then move the tasks in the empty
1730 * cpuset to its next-highest non-empty parent.
1732 * The parent cpuset has some superset of the 'mems' nodes that the
1733 * newly empty cpuset held, so no migration of memory is necessary.
1735 * Called with both manage_sem and callback_sem held
1737 static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
1739 struct cpuset *parent;
1741 /* the cgroup's css_sets list is in use if there are tasks
1742 in the cpuset; the list is empty if there are none;
1743 the cs->css.refcnt seems always 0 */
1744 if (list_empty(&cs->css.cgroup->css_sets))
1748 * Find its next-highest non-empty parent, (top cpuset
1749 * has online cpus, so can't be empty).
1751 parent = cs->parent;
1752 while (cpus_empty(parent->cpus_allowed)) {
1754 * this empty cpuset should now be considered to
1755 * have been used, and therefore eligible for
1756 * release when empty (if it is notify_on_release)
1758 parent = parent->parent;
1761 move_member_tasks_to_cpuset(cs, parent);
1765 * Walk the specified cpuset subtree and look for empty cpusets.
1766 * The tasks of such cpuset must be moved to a parent cpuset.
1768 * Note that such a notify_on_release cpuset must have had, at some time,
1769 * member tasks or cpuset descendants and cpus and memory, before it can
1770 * be a candidate for release.
1772 * Called with manage_mutex held. We take callback_mutex to modify
1773 * cpus_allowed and mems_allowed.
1775 * This walk processes the tree from top to bottom, completing one layer
1776 * before dropping down to the next. It always processes a node before
1777 * any of its children.
1779 * For now, since we lack memory hot unplug, we'll never see a cpuset
1780 * that has tasks along with an empty 'mems'. But if we did see such
1781 * a cpuset, we'd handle it just like we do if its 'cpus' was empty.
1783 static void scan_for_empty_cpusets(const struct cpuset *root)
1785 struct cpuset *cp; /* scans cpusets being updated */
1786 struct cpuset *child; /* scans child cpusets of cp */
1787 struct list_head queue;
1788 struct cgroup *cont;
1790 INIT_LIST_HEAD(&queue);
1792 list_add_tail((struct list_head *)&root->stack_list, &queue);
1794 mutex_lock(&callback_mutex);
1795 while (!list_empty(&queue)) {
1796 cp = container_of(queue.next, struct cpuset, stack_list);
1797 list_del(queue.next);
1798 list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
1799 child = cgroup_cs(cont);
1800 list_add_tail(&child->stack_list, &queue);
1802 cont = cp->css.cgroup;
1803 /* Remove offline cpus and mems from this cpuset. */
1804 cpus_and(cp->cpus_allowed, cp->cpus_allowed, cpu_online_map);
1805 nodes_and(cp->mems_allowed, cp->mems_allowed,
1806 node_states[N_HIGH_MEMORY]);
1807 if ((cpus_empty(cp->cpus_allowed) ||
1808 nodes_empty(cp->mems_allowed))) {
1809 /* Move tasks from the empty cpuset to a parent */
1810 mutex_unlock(&callback_mutex);
1811 remove_tasks_in_empty_cpuset(cp);
1812 mutex_lock(&callback_mutex);
1815 mutex_unlock(&callback_mutex);
1820 * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
1821 * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to
1822 * track what's online after any CPU or memory node hotplug or unplug event.
1824 * Since there are two callers of this routine, one for CPU hotplug
1825 * events and one for memory node hotplug events, we could have coded
1826 * two separate routines here. We code it as a single common routine
1827 * in order to minimize text size.
1830 static void common_cpu_mem_hotplug_unplug(void)
1834 top_cpuset.cpus_allowed = cpu_online_map;
1835 top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
1836 scan_for_empty_cpusets(&top_cpuset);
1842 * The top_cpuset tracks what CPUs and Memory Nodes are online,
1843 * period. This is necessary in order to make cpusets transparent
1844 * (of no affect) on systems that are actively using CPU hotplug
1845 * but making no active use of cpusets.
1847 * This routine ensures that top_cpuset.cpus_allowed tracks
1848 * cpu_online_map on each CPU hotplug (cpuhp) event.
1851 static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
1852 unsigned long phase, void *unused_cpu)
1854 if (phase == CPU_DYING || phase == CPU_DYING_FROZEN)
1857 common_cpu_mem_hotplug_unplug();
1861 #ifdef CONFIG_MEMORY_HOTPLUG
1863 * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
1864 * Call this routine anytime after you change
1865 * node_states[N_HIGH_MEMORY].
1866 * See also the previous routine cpuset_handle_cpuhp().
1869 void cpuset_track_online_nodes(void)
1871 common_cpu_mem_hotplug_unplug();
1876 * cpuset_init_smp - initialize cpus_allowed
1878 * Description: Finish top cpuset after cpu, node maps are initialized
1881 void __init cpuset_init_smp(void)
1883 top_cpuset.cpus_allowed = cpu_online_map;
1884 top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
1886 hotcpu_notifier(cpuset_handle_cpuhp, 0);
1891 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
1892 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
1894 * Description: Returns the cpumask_t cpus_allowed of the cpuset
1895 * attached to the specified @tsk. Guaranteed to return some non-empty
1896 * subset of cpu_online_map, even if this means going outside the
1900 cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
1904 mutex_lock(&callback_mutex);
1905 mask = cpuset_cpus_allowed_locked(tsk);
1906 mutex_unlock(&callback_mutex);
1912 * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
1913 * Must be called with callback_mutex held.
1915 cpumask_t cpuset_cpus_allowed_locked(struct task_struct *tsk)
1920 guarantee_online_cpus(task_cs(tsk), &mask);
1926 void cpuset_init_current_mems_allowed(void)
1928 current->mems_allowed = NODE_MASK_ALL;
1932 * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
1933 * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
1935 * Description: Returns the nodemask_t mems_allowed of the cpuset
1936 * attached to the specified @tsk. Guaranteed to return some non-empty
1937 * subset of node_states[N_HIGH_MEMORY], even if this means going outside the
1941 nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
1945 mutex_lock(&callback_mutex);
1947 guarantee_online_mems(task_cs(tsk), &mask);
1949 mutex_unlock(&callback_mutex);
1955 * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed
1956 * @zl: the zonelist to be checked
1958 * Are any of the nodes on zonelist zl allowed in current->mems_allowed?
1960 int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
1964 for (i = 0; zl->zones[i]; i++) {
1965 int nid = zone_to_nid(zl->zones[i]);
1967 if (node_isset(nid, current->mems_allowed))
1974 * nearest_exclusive_ancestor() - Returns the nearest mem_exclusive
1975 * ancestor to the specified cpuset. Call holding callback_mutex.
1976 * If no ancestor is mem_exclusive (an unusual configuration), then
1977 * returns the root cpuset.
1979 static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
1981 while (!is_mem_exclusive(cs) && cs->parent)
1987 * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
1988 * @z: is this zone on an allowed node?
1989 * @gfp_mask: memory allocation flags
1991 * If we're in interrupt, yes, we can always allocate. If
1992 * __GFP_THISNODE is set, yes, we can always allocate. If zone
1993 * z's node is in our tasks mems_allowed, yes. If it's not a
1994 * __GFP_HARDWALL request and this zone's nodes is in the nearest
1995 * mem_exclusive cpuset ancestor to this tasks cpuset, yes.
1996 * If the task has been OOM killed and has access to memory reserves
1997 * as specified by the TIF_MEMDIE flag, yes.
2000 * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
2001 * reduces to cpuset_zone_allowed_hardwall(). Otherwise,
2002 * cpuset_zone_allowed_softwall() might sleep, and might allow a zone
2003 * from an enclosing cpuset.
2005 * cpuset_zone_allowed_hardwall() only handles the simpler case of
2006 * hardwall cpusets, and never sleeps.
2008 * The __GFP_THISNODE placement logic is really handled elsewhere,
2009 * by forcibly using a zonelist starting at a specified node, and by
2010 * (in get_page_from_freelist()) refusing to consider the zones for
2011 * any node on the zonelist except the first. By the time any such
2012 * calls get to this routine, we should just shut up and say 'yes'.
2014 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
2015 * and do not allow allocations outside the current tasks cpuset
2016 * unless the task has been OOM killed as is marked TIF_MEMDIE.
2017 * GFP_KERNEL allocations are not so marked, so can escape to the
2018 * nearest enclosing mem_exclusive ancestor cpuset.
2020 * Scanning up parent cpusets requires callback_mutex. The
2021 * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
2022 * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
2023 * current tasks mems_allowed came up empty on the first pass over
2024 * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
2025 * cpuset are short of memory, might require taking the callback_mutex
2028 * The first call here from mm/page_alloc:get_page_from_freelist()
2029 * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
2030 * so no allocation on a node outside the cpuset is allowed (unless
2031 * in interrupt, of course).
2033 * The second pass through get_page_from_freelist() doesn't even call
2034 * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
2035 * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
2036 * in alloc_flags. That logic and the checks below have the combined
2038 * in_interrupt - any node ok (current task context irrelevant)
2039 * GFP_ATOMIC - any node ok
2040 * TIF_MEMDIE - any node ok
2041 * GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok
2042 * GFP_USER - only nodes in current tasks mems allowed ok.
2045 * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
2046 * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
2047 * the code that might scan up ancestor cpusets and sleep.
2050 int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
2052 int node; /* node that zone z is on */
2053 const struct cpuset *cs; /* current cpuset ancestors */
2054 int allowed; /* is allocation in zone z allowed? */
2056 if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
2058 node = zone_to_nid(z);
2059 might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
2060 if (node_isset(node, current->mems_allowed))
2063 * Allow tasks that have access to memory reserves because they have
2064 * been OOM killed to get memory anywhere.
2066 if (unlikely(test_thread_flag(TIF_MEMDIE)))
2068 if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
2071 if (current->flags & PF_EXITING) /* Let dying task have memory */
2074 /* Not hardwall and node outside mems_allowed: scan up cpusets */
2075 mutex_lock(&callback_mutex);
2078 cs = nearest_exclusive_ancestor(task_cs(current));
2079 task_unlock(current);
2081 allowed = node_isset(node, cs->mems_allowed);
2082 mutex_unlock(&callback_mutex);
2087 * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
2088 * @z: is this zone on an allowed node?
2089 * @gfp_mask: memory allocation flags
2091 * If we're in interrupt, yes, we can always allocate.
2092 * If __GFP_THISNODE is set, yes, we can always allocate. If zone
2093 * z's node is in our tasks mems_allowed, yes. If the task has been
2094 * OOM killed and has access to memory reserves as specified by the
2095 * TIF_MEMDIE flag, yes. Otherwise, no.
2097 * The __GFP_THISNODE placement logic is really handled elsewhere,
2098 * by forcibly using a zonelist starting at a specified node, and by
2099 * (in get_page_from_freelist()) refusing to consider the zones for
2100 * any node on the zonelist except the first. By the time any such
2101 * calls get to this routine, we should just shut up and say 'yes'.
2103 * Unlike the cpuset_zone_allowed_softwall() variant, above,
2104 * this variant requires that the zone be in the current tasks
2105 * mems_allowed or that we're in interrupt. It does not scan up the
2106 * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
2110 int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
2112 int node; /* node that zone z is on */
2114 if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
2116 node = zone_to_nid(z);
2117 if (node_isset(node, current->mems_allowed))
2120 * Allow tasks that have access to memory reserves because they have
2121 * been OOM killed to get memory anywhere.
2123 if (unlikely(test_thread_flag(TIF_MEMDIE)))
2129 * cpuset_lock - lock out any changes to cpuset structures
2131 * The out of memory (oom) code needs to mutex_lock cpusets
2132 * from being changed while it scans the tasklist looking for a
2133 * task in an overlapping cpuset. Expose callback_mutex via this
2134 * cpuset_lock() routine, so the oom code can lock it, before
2135 * locking the task list. The tasklist_lock is a spinlock, so
2136 * must be taken inside callback_mutex.
2139 void cpuset_lock(void)
2141 mutex_lock(&callback_mutex);
2145 * cpuset_unlock - release lock on cpuset changes
2147 * Undo the lock taken in a previous cpuset_lock() call.
2150 void cpuset_unlock(void)
2152 mutex_unlock(&callback_mutex);
2156 * cpuset_mem_spread_node() - On which node to begin search for a page
2158 * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
2159 * tasks in a cpuset with is_spread_page or is_spread_slab set),
2160 * and if the memory allocation used cpuset_mem_spread_node()
2161 * to determine on which node to start looking, as it will for
2162 * certain page cache or slab cache pages such as used for file
2163 * system buffers and inode caches, then instead of starting on the
2164 * local node to look for a free page, rather spread the starting
2165 * node around the tasks mems_allowed nodes.
2167 * We don't have to worry about the returned node being offline
2168 * because "it can't happen", and even if it did, it would be ok.
2170 * The routines calling guarantee_online_mems() are careful to
2171 * only set nodes in task->mems_allowed that are online. So it
2172 * should not be possible for the following code to return an
2173 * offline node. But if it did, that would be ok, as this routine
2174 * is not returning the node where the allocation must be, only
2175 * the node where the search should start. The zonelist passed to
2176 * __alloc_pages() will include all nodes. If the slab allocator
2177 * is passed an offline node, it will fall back to the local node.
2178 * See kmem_cache_alloc_node().
2181 int cpuset_mem_spread_node(void)
2185 node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
2186 if (node == MAX_NUMNODES)
2187 node = first_node(current->mems_allowed);
2188 current->cpuset_mem_spread_rotor = node;
2191 EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
2194 * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
2195 * @tsk1: pointer to task_struct of some task.
2196 * @tsk2: pointer to task_struct of some other task.
2198 * Description: Return true if @tsk1's mems_allowed intersects the
2199 * mems_allowed of @tsk2. Used by the OOM killer to determine if
2200 * one of the task's memory usage might impact the memory available
2204 int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
2205 const struct task_struct *tsk2)
2207 return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
2211 * Collection of memory_pressure is suppressed unless
2212 * this flag is enabled by writing "1" to the special
2213 * cpuset file 'memory_pressure_enabled' in the root cpuset.
2216 int cpuset_memory_pressure_enabled __read_mostly;
2219 * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
2221 * Keep a running average of the rate of synchronous (direct)
2222 * page reclaim efforts initiated by tasks in each cpuset.
2224 * This represents the rate at which some task in the cpuset
2225 * ran low on memory on all nodes it was allowed to use, and
2226 * had to enter the kernels page reclaim code in an effort to
2227 * create more free memory by tossing clean pages or swapping
2228 * or writing dirty pages.
2230 * Display to user space in the per-cpuset read-only file
2231 * "memory_pressure". Value displayed is an integer
2232 * representing the recent rate of entry into the synchronous
2233 * (direct) page reclaim by any task attached to the cpuset.
2236 void __cpuset_memory_pressure_bump(void)
2239 fmeter_markevent(&task_cs(current)->fmeter);
2240 task_unlock(current);
2243 #ifdef CONFIG_PROC_PID_CPUSET
2245 * proc_cpuset_show()
2246 * - Print tasks cpuset path into seq_file.
2247 * - Used for /proc/<pid>/cpuset.
2248 * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
2249 * doesn't really matter if tsk->cpuset changes after we read it,
2250 * and we take manage_mutex, keeping attach_task() from changing it
2251 * anyway. No need to check that tsk->cpuset != NULL, thanks to
2252 * the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks
2253 * cpuset to top_cpuset.
2255 static int proc_cpuset_show(struct seq_file *m, void *unused_v)
2258 struct task_struct *tsk;
2260 struct cgroup_subsys_state *css;
2264 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
2270 tsk = get_pid_task(pid, PIDTYPE_PID);
2276 css = task_subsys_state(tsk, cpuset_subsys_id);
2277 retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
2284 put_task_struct(tsk);
2291 static int cpuset_open(struct inode *inode, struct file *file)
2293 struct pid *pid = PROC_I(inode)->pid;
2294 return single_open(file, proc_cpuset_show, pid);
2297 const struct file_operations proc_cpuset_operations = {
2298 .open = cpuset_open,
2300 .llseek = seq_lseek,
2301 .release = single_release,
2303 #endif /* CONFIG_PROC_PID_CPUSET */
2305 /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
2306 char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
2308 buffer += sprintf(buffer, "Cpus_allowed:\t");
2309 buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
2310 buffer += sprintf(buffer, "\n");
2311 buffer += sprintf(buffer, "Mems_allowed:\t");
2312 buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
2313 buffer += sprintf(buffer, "\n");