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
17 * 2008 Rework of the scheduler domains and CPU hotplug handling
20 * This file is subject to the terms and conditions of the GNU General Public
21 * License. See the file COPYING in the main directory of the Linux
22 * distribution for more details.
25 #include <linux/cpu.h>
26 #include <linux/cpumask.h>
27 #include <linux/cpuset.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/file.h>
32 #include <linux/init.h>
33 #include <linux/interrupt.h>
34 #include <linux/kernel.h>
35 #include <linux/kmod.h>
36 #include <linux/list.h>
37 #include <linux/mempolicy.h>
39 #include <linux/memory.h>
40 #include <linux/export.h>
41 #include <linux/mount.h>
42 #include <linux/namei.h>
43 #include <linux/pagemap.h>
44 #include <linux/proc_fs.h>
45 #include <linux/rcupdate.h>
46 #include <linux/sched.h>
47 #include <linux/sched/mm.h>
48 #include <linux/sched/task.h>
49 #include <linux/seq_file.h>
50 #include <linux/security.h>
51 #include <linux/slab.h>
52 #include <linux/spinlock.h>
53 #include <linux/stat.h>
54 #include <linux/string.h>
55 #include <linux/time.h>
56 #include <linux/time64.h>
57 #include <linux/backing-dev.h>
58 #include <linux/sort.h>
59 #include <linux/oom.h>
60 #include <linux/sched/isolation.h>
61 #include <linux/uaccess.h>
62 #include <linux/atomic.h>
63 #include <linux/mutex.h>
64 #include <linux/cgroup.h>
65 #include <linux/wait.h>
67 DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
68 DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
70 /* See "Frequency meter" comments, below. */
73 int cnt; /* unprocessed events count */
74 int val; /* most recent output value */
75 time64_t time; /* clock (secs) when val computed */
76 spinlock_t lock; /* guards read or write of above */
80 struct cgroup_subsys_state css;
82 unsigned long flags; /* "unsigned long" so bitops work */
85 * On default hierarchy:
87 * The user-configured masks can only be changed by writing to
88 * cpuset.cpus and cpuset.mems, and won't be limited by the
91 * The effective masks is the real masks that apply to the tasks
92 * in the cpuset. They may be changed if the configured masks are
93 * changed or hotplug happens.
95 * effective_mask == configured_mask & parent's effective_mask,
96 * and if it ends up empty, it will inherit the parent's mask.
101 * The user-configured masks are always the same with effective masks.
104 /* user-configured CPUs and Memory Nodes allow to tasks */
105 cpumask_var_t cpus_allowed;
106 nodemask_t mems_allowed;
108 /* effective CPUs and Memory Nodes allow to tasks */
109 cpumask_var_t effective_cpus;
110 nodemask_t effective_mems;
113 * CPUs allocated to child sub-partitions (default hierarchy only)
114 * - CPUs granted by the parent = effective_cpus U subparts_cpus
115 * - effective_cpus and subparts_cpus are mutually exclusive.
117 cpumask_var_t subparts_cpus;
120 * This is old Memory Nodes tasks took on.
122 * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
123 * - A new cpuset's old_mems_allowed is initialized when some
124 * task is moved into it.
125 * - old_mems_allowed is used in cpuset_migrate_mm() when we change
126 * cpuset.mems_allowed and have tasks' nodemask updated, and
127 * then old_mems_allowed is updated to mems_allowed.
129 nodemask_t old_mems_allowed;
131 struct fmeter fmeter; /* memory_pressure filter */
134 * Tasks are being attached to this cpuset. Used to prevent
135 * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
137 int attach_in_progress;
139 /* partition number for rebuild_sched_domains() */
142 /* for custom sched domain */
143 int relax_domain_level;
145 /* number of CPUs in subparts_cpus */
146 int nr_subparts_cpus;
148 /* partition root state */
149 int partition_root_state;
153 * Partition root states:
155 * 0 - not a partition root
159 * -1 - invalid partition root
160 * None of the cpus in cpus_allowed can be put into the parent's
161 * subparts_cpus. In this case, the cpuset is not a real partition
162 * root anymore. However, the CPU_EXCLUSIVE bit will still be set
163 * and the cpuset can be restored back to a partition root if the
164 * parent cpuset can give more CPUs back to this child cpuset.
166 #define PRS_DISABLED 0
167 #define PRS_ENABLED 1
171 * Temporary cpumasks for working with partitions that are passed among
172 * functions to avoid memory allocation in inner functions.
175 cpumask_var_t addmask, delmask; /* For partition root */
176 cpumask_var_t new_cpus; /* For update_cpumasks_hier() */
179 static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
181 return css ? container_of(css, struct cpuset, css) : NULL;
184 /* Retrieve the cpuset for a task */
185 static inline struct cpuset *task_cs(struct task_struct *task)
187 return css_cs(task_css(task, cpuset_cgrp_id));
190 static inline struct cpuset *parent_cs(struct cpuset *cs)
192 return css_cs(cs->css.parent);
196 static inline bool task_has_mempolicy(struct task_struct *task)
198 return task->mempolicy;
201 static inline bool task_has_mempolicy(struct task_struct *task)
208 /* bits in struct cpuset flags field */
215 CS_SCHED_LOAD_BALANCE,
220 /* convenient tests for these bits */
221 static inline bool is_cpuset_online(struct cpuset *cs)
223 return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
226 static inline int is_cpu_exclusive(const struct cpuset *cs)
228 return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
231 static inline int is_mem_exclusive(const struct cpuset *cs)
233 return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
236 static inline int is_mem_hardwall(const struct cpuset *cs)
238 return test_bit(CS_MEM_HARDWALL, &cs->flags);
241 static inline int is_sched_load_balance(const struct cpuset *cs)
243 return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
246 static inline int is_memory_migrate(const struct cpuset *cs)
248 return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
251 static inline int is_spread_page(const struct cpuset *cs)
253 return test_bit(CS_SPREAD_PAGE, &cs->flags);
256 static inline int is_spread_slab(const struct cpuset *cs)
258 return test_bit(CS_SPREAD_SLAB, &cs->flags);
261 static inline int is_partition_root(const struct cpuset *cs)
263 return cs->partition_root_state > 0;
266 static struct cpuset top_cpuset = {
267 .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
268 (1 << CS_MEM_EXCLUSIVE)),
269 .partition_root_state = PRS_ENABLED,
273 * cpuset_for_each_child - traverse online children of a cpuset
274 * @child_cs: loop cursor pointing to the current child
275 * @pos_css: used for iteration
276 * @parent_cs: target cpuset to walk children of
278 * Walk @child_cs through the online children of @parent_cs. Must be used
279 * with RCU read locked.
281 #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
282 css_for_each_child((pos_css), &(parent_cs)->css) \
283 if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
286 * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
287 * @des_cs: loop cursor pointing to the current descendant
288 * @pos_css: used for iteration
289 * @root_cs: target cpuset to walk ancestor of
291 * Walk @des_cs through the online descendants of @root_cs. Must be used
292 * with RCU read locked. The caller may modify @pos_css by calling
293 * css_rightmost_descendant() to skip subtree. @root_cs is included in the
294 * iteration and the first node to be visited.
296 #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
297 css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
298 if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
301 * There are two global locks guarding cpuset structures - cpuset_mutex and
302 * callback_lock. We also require taking task_lock() when dereferencing a
303 * task's cpuset pointer. See "The task_lock() exception", at the end of this
306 * A task must hold both locks to modify cpusets. If a task holds
307 * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
308 * is the only task able to also acquire callback_lock and be able to
309 * modify cpusets. It can perform various checks on the cpuset structure
310 * first, knowing nothing will change. It can also allocate memory while
311 * just holding cpuset_mutex. While it is performing these checks, various
312 * callback routines can briefly acquire callback_lock to query cpusets.
313 * Once it is ready to make the changes, it takes callback_lock, blocking
316 * Calls to the kernel memory allocator can not be made while holding
317 * callback_lock, as that would risk double tripping on callback_lock
318 * from one of the callbacks into the cpuset code from within
321 * If a task is only holding callback_lock, then it has read-only
324 * Now, the task_struct fields mems_allowed and mempolicy may be changed
325 * by other task, we use alloc_lock in the task_struct fields to protect
328 * The cpuset_common_file_read() handlers only hold callback_lock across
329 * small pieces of code, such as when reading out possibly multi-word
330 * cpumasks and nodemasks.
332 * Accessing a task's cpuset should be done in accordance with the
333 * guidelines for accessing subsystem state in kernel/cgroup.c
336 static DEFINE_MUTEX(cpuset_mutex);
337 static DEFINE_SPINLOCK(callback_lock);
339 static struct workqueue_struct *cpuset_migrate_mm_wq;
342 * CPU / memory hotplug is handled asynchronously.
344 static void cpuset_hotplug_workfn(struct work_struct *work);
345 static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
347 static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
350 * Cgroup v2 behavior is used when on default hierarchy or the
351 * cgroup_v2_mode flag is set.
353 static inline bool is_in_v2_mode(void)
355 return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
356 (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
360 * This is ugly, but preserves the userspace API for existing cpuset
361 * users. If someone tries to mount the "cpuset" filesystem, we
362 * silently switch it to mount "cgroup" instead
364 static struct dentry *cpuset_mount(struct file_system_type *fs_type,
365 int flags, const char *unused_dev_name, void *data)
367 struct file_system_type *cgroup_fs = get_fs_type("cgroup");
368 struct dentry *ret = ERR_PTR(-ENODEV);
372 "release_agent=/sbin/cpuset_release_agent";
373 ret = cgroup_fs->mount(cgroup_fs, flags,
374 unused_dev_name, mountopts);
375 put_filesystem(cgroup_fs);
380 static struct file_system_type cpuset_fs_type = {
382 .mount = cpuset_mount,
386 * Return in pmask the portion of a cpusets's cpus_allowed that
387 * are online. If none are online, walk up the cpuset hierarchy
388 * until we find one that does have some online cpus.
390 * One way or another, we guarantee to return some non-empty subset
391 * of cpu_online_mask.
393 * Call with callback_lock or cpuset_mutex held.
395 static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
397 while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
401 * The top cpuset doesn't have any online cpu as a
402 * consequence of a race between cpuset_hotplug_work
403 * and cpu hotplug notifier. But we know the top
404 * cpuset's effective_cpus is on its way to to be
405 * identical to cpu_online_mask.
407 cpumask_copy(pmask, cpu_online_mask);
411 cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
415 * Return in *pmask the portion of a cpusets's mems_allowed that
416 * are online, with memory. If none are online with memory, walk
417 * up the cpuset hierarchy until we find one that does have some
418 * online mems. The top cpuset always has some mems online.
420 * One way or another, we guarantee to return some non-empty subset
421 * of node_states[N_MEMORY].
423 * Call with callback_lock or cpuset_mutex held.
425 static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
427 while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
429 nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
433 * update task's spread flag if cpuset's page/slab spread flag is set
435 * Call with callback_lock or cpuset_mutex held.
437 static void cpuset_update_task_spread_flag(struct cpuset *cs,
438 struct task_struct *tsk)
440 if (is_spread_page(cs))
441 task_set_spread_page(tsk);
443 task_clear_spread_page(tsk);
445 if (is_spread_slab(cs))
446 task_set_spread_slab(tsk);
448 task_clear_spread_slab(tsk);
452 * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
454 * One cpuset is a subset of another if all its allowed CPUs and
455 * Memory Nodes are a subset of the other, and its exclusive flags
456 * are only set if the other's are set. Call holding cpuset_mutex.
459 static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
461 return cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
462 nodes_subset(p->mems_allowed, q->mems_allowed) &&
463 is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
464 is_mem_exclusive(p) <= is_mem_exclusive(q);
468 * alloc_cpumasks - allocate three cpumasks for cpuset
469 * @cs: the cpuset that have cpumasks to be allocated.
470 * @tmp: the tmpmasks structure pointer
471 * Return: 0 if successful, -ENOMEM otherwise.
473 * Only one of the two input arguments should be non-NULL.
475 static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
477 cpumask_var_t *pmask1, *pmask2, *pmask3;
480 pmask1 = &cs->cpus_allowed;
481 pmask2 = &cs->effective_cpus;
482 pmask3 = &cs->subparts_cpus;
484 pmask1 = &tmp->new_cpus;
485 pmask2 = &tmp->addmask;
486 pmask3 = &tmp->delmask;
489 if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))
492 if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))
495 if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))
501 free_cpumask_var(*pmask2);
503 free_cpumask_var(*pmask1);
508 * free_cpumasks - free cpumasks in a tmpmasks structure
509 * @cs: the cpuset that have cpumasks to be free.
510 * @tmp: the tmpmasks structure pointer
512 static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
515 free_cpumask_var(cs->cpus_allowed);
516 free_cpumask_var(cs->effective_cpus);
517 free_cpumask_var(cs->subparts_cpus);
520 free_cpumask_var(tmp->new_cpus);
521 free_cpumask_var(tmp->addmask);
522 free_cpumask_var(tmp->delmask);
527 * alloc_trial_cpuset - allocate a trial cpuset
528 * @cs: the cpuset that the trial cpuset duplicates
530 static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
532 struct cpuset *trial;
534 trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
538 if (alloc_cpumasks(trial, NULL)) {
543 cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
544 cpumask_copy(trial->effective_cpus, cs->effective_cpus);
549 * free_cpuset - free the cpuset
550 * @cs: the cpuset to be freed
552 static inline void free_cpuset(struct cpuset *cs)
554 free_cpumasks(cs, NULL);
559 * validate_change() - Used to validate that any proposed cpuset change
560 * follows the structural rules for cpusets.
562 * If we replaced the flag and mask values of the current cpuset
563 * (cur) with those values in the trial cpuset (trial), would
564 * our various subset and exclusive rules still be valid? Presumes
567 * 'cur' is the address of an actual, in-use cpuset. Operations
568 * such as list traversal that depend on the actual address of the
569 * cpuset in the list must use cur below, not trial.
571 * 'trial' is the address of bulk structure copy of cur, with
572 * perhaps one or more of the fields cpus_allowed, mems_allowed,
573 * or flags changed to new, trial values.
575 * Return 0 if valid, -errno if not.
578 static int validate_change(struct cpuset *cur, struct cpuset *trial)
580 struct cgroup_subsys_state *css;
581 struct cpuset *c, *par;
586 /* Each of our child cpusets must be a subset of us */
588 cpuset_for_each_child(c, css, cur)
589 if (!is_cpuset_subset(c, trial))
592 /* Remaining checks don't apply to root cpuset */
594 if (cur == &top_cpuset)
597 par = parent_cs(cur);
599 /* On legacy hiearchy, we must be a subset of our parent cpuset. */
601 if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
605 * If either I or some sibling (!= me) is exclusive, we can't
609 cpuset_for_each_child(c, css, par) {
610 if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
612 cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
614 if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
616 nodes_intersects(trial->mems_allowed, c->mems_allowed))
621 * Cpusets with tasks - existing or newly being attached - can't
622 * be changed to have empty cpus_allowed or mems_allowed.
625 if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
626 if (!cpumask_empty(cur->cpus_allowed) &&
627 cpumask_empty(trial->cpus_allowed))
629 if (!nodes_empty(cur->mems_allowed) &&
630 nodes_empty(trial->mems_allowed))
635 * We can't shrink if we won't have enough room for SCHED_DEADLINE
639 if (is_cpu_exclusive(cur) &&
640 !cpuset_cpumask_can_shrink(cur->cpus_allowed,
641 trial->cpus_allowed))
652 * Helper routine for generate_sched_domains().
653 * Do cpusets a, b have overlapping effective cpus_allowed masks?
655 static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
657 return cpumask_intersects(a->effective_cpus, b->effective_cpus);
661 update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
663 if (dattr->relax_domain_level < c->relax_domain_level)
664 dattr->relax_domain_level = c->relax_domain_level;
668 static void update_domain_attr_tree(struct sched_domain_attr *dattr,
669 struct cpuset *root_cs)
672 struct cgroup_subsys_state *pos_css;
675 cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
676 /* skip the whole subtree if @cp doesn't have any CPU */
677 if (cpumask_empty(cp->cpus_allowed)) {
678 pos_css = css_rightmost_descendant(pos_css);
682 if (is_sched_load_balance(cp))
683 update_domain_attr(dattr, cp);
688 /* Must be called with cpuset_mutex held. */
689 static inline int nr_cpusets(void)
691 /* jump label reference count + the top-level cpuset */
692 return static_key_count(&cpusets_enabled_key.key) + 1;
696 * generate_sched_domains()
698 * This function builds a partial partition of the systems CPUs
699 * A 'partial partition' is a set of non-overlapping subsets whose
700 * union is a subset of that set.
701 * The output of this function needs to be passed to kernel/sched/core.c
702 * partition_sched_domains() routine, which will rebuild the scheduler's
703 * load balancing domains (sched domains) as specified by that partial
706 * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.txt
707 * for a background explanation of this.
709 * Does not return errors, on the theory that the callers of this
710 * routine would rather not worry about failures to rebuild sched
711 * domains when operating in the severe memory shortage situations
712 * that could cause allocation failures below.
714 * Must be called with cpuset_mutex held.
716 * The three key local variables below are:
717 * q - a linked-list queue of cpuset pointers, used to implement a
718 * top-down scan of all cpusets. This scan loads a pointer
719 * to each cpuset marked is_sched_load_balance into the
720 * array 'csa'. For our purposes, rebuilding the schedulers
721 * sched domains, we can ignore !is_sched_load_balance cpusets.
722 * csa - (for CpuSet Array) Array of pointers to all the cpusets
723 * that need to be load balanced, for convenient iterative
724 * access by the subsequent code that finds the best partition,
725 * i.e the set of domains (subsets) of CPUs such that the
726 * cpus_allowed of every cpuset marked is_sched_load_balance
727 * is a subset of one of these domains, while there are as
728 * many such domains as possible, each as small as possible.
729 * doms - Conversion of 'csa' to an array of cpumasks, for passing to
730 * the kernel/sched/core.c routine partition_sched_domains() in a
731 * convenient format, that can be easily compared to the prior
732 * value to determine what partition elements (sched domains)
733 * were changed (added or removed.)
735 * Finding the best partition (set of domains):
736 * The triple nested loops below over i, j, k scan over the
737 * load balanced cpusets (using the array of cpuset pointers in
738 * csa[]) looking for pairs of cpusets that have overlapping
739 * cpus_allowed, but which don't have the same 'pn' partition
740 * number and gives them in the same partition number. It keeps
741 * looping on the 'restart' label until it can no longer find
744 * The union of the cpus_allowed masks from the set of
745 * all cpusets having the same 'pn' value then form the one
746 * element of the partition (one sched domain) to be passed to
747 * partition_sched_domains().
749 static int generate_sched_domains(cpumask_var_t **domains,
750 struct sched_domain_attr **attributes)
752 struct cpuset *cp; /* scans q */
753 struct cpuset **csa; /* array of all cpuset ptrs */
754 int csn; /* how many cpuset ptrs in csa so far */
755 int i, j, k; /* indices for partition finding loops */
756 cpumask_var_t *doms; /* resulting partition; i.e. sched domains */
757 struct sched_domain_attr *dattr; /* attributes for custom domains */
758 int ndoms = 0; /* number of sched domains in result */
759 int nslot; /* next empty doms[] struct cpumask slot */
760 struct cgroup_subsys_state *pos_css;
766 /* Special case for the 99% of systems with one, full, sched domain */
767 if (is_sched_load_balance(&top_cpuset)) {
769 doms = alloc_sched_domains(ndoms);
773 dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
775 *dattr = SD_ATTR_INIT;
776 update_domain_attr_tree(dattr, &top_cpuset);
778 cpumask_and(doms[0], top_cpuset.effective_cpus,
779 housekeeping_cpumask(HK_FLAG_DOMAIN));
784 csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL);
790 cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
791 if (cp == &top_cpuset)
794 * Continue traversing beyond @cp iff @cp has some CPUs and
795 * isn't load balancing. The former is obvious. The
796 * latter: All child cpusets contain a subset of the
797 * parent's cpus, so just skip them, and then we call
798 * update_domain_attr_tree() to calc relax_domain_level of
799 * the corresponding sched domain.
801 if (!cpumask_empty(cp->cpus_allowed) &&
802 !(is_sched_load_balance(cp) &&
803 cpumask_intersects(cp->cpus_allowed,
804 housekeeping_cpumask(HK_FLAG_DOMAIN))))
807 if (is_sched_load_balance(cp))
810 /* skip @cp's subtree */
811 pos_css = css_rightmost_descendant(pos_css);
815 for (i = 0; i < csn; i++)
820 /* Find the best partition (set of sched domains) */
821 for (i = 0; i < csn; i++) {
822 struct cpuset *a = csa[i];
825 for (j = 0; j < csn; j++) {
826 struct cpuset *b = csa[j];
829 if (apn != bpn && cpusets_overlap(a, b)) {
830 for (k = 0; k < csn; k++) {
831 struct cpuset *c = csa[k];
836 ndoms--; /* one less element */
843 * Now we know how many domains to create.
844 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
846 doms = alloc_sched_domains(ndoms);
851 * The rest of the code, including the scheduler, can deal with
852 * dattr==NULL case. No need to abort if alloc fails.
854 dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr),
857 for (nslot = 0, i = 0; i < csn; i++) {
858 struct cpuset *a = csa[i];
863 /* Skip completed partitions */
869 if (nslot == ndoms) {
870 static int warnings = 10;
872 pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
873 nslot, ndoms, csn, i, apn);
881 *(dattr + nslot) = SD_ATTR_INIT;
882 for (j = i; j < csn; j++) {
883 struct cpuset *b = csa[j];
886 cpumask_or(dp, dp, b->effective_cpus);
887 cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
889 update_domain_attr_tree(dattr + nslot, b);
891 /* Done with this partition */
897 BUG_ON(nslot != ndoms);
903 * Fallback to the default domain if kmalloc() failed.
904 * See comments in partition_sched_domains().
915 * Rebuild scheduler domains.
917 * If the flag 'sched_load_balance' of any cpuset with non-empty
918 * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
919 * which has that flag enabled, or if any cpuset with a non-empty
920 * 'cpus' is removed, then call this routine to rebuild the
921 * scheduler's dynamic sched domains.
923 * Call with cpuset_mutex held. Takes get_online_cpus().
925 static void rebuild_sched_domains_locked(void)
927 struct sched_domain_attr *attr;
931 lockdep_assert_held(&cpuset_mutex);
935 * We have raced with CPU hotplug. Don't do anything to avoid
936 * passing doms with offlined cpu to partition_sched_domains().
937 * Anyways, hotplug work item will rebuild sched domains.
939 if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
942 /* Generate domain masks and attrs */
943 ndoms = generate_sched_domains(&doms, &attr);
945 /* Have scheduler rebuild the domains */
946 partition_sched_domains(ndoms, doms, attr);
950 #else /* !CONFIG_SMP */
951 static void rebuild_sched_domains_locked(void)
954 #endif /* CONFIG_SMP */
956 void rebuild_sched_domains(void)
958 mutex_lock(&cpuset_mutex);
959 rebuild_sched_domains_locked();
960 mutex_unlock(&cpuset_mutex);
964 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
965 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
967 * Iterate through each task of @cs updating its cpus_allowed to the
968 * effective cpuset's. As this function is called with cpuset_mutex held,
969 * cpuset membership stays stable.
971 static void update_tasks_cpumask(struct cpuset *cs)
973 struct css_task_iter it;
974 struct task_struct *task;
976 css_task_iter_start(&cs->css, 0, &it);
977 while ((task = css_task_iter_next(&it)))
978 set_cpus_allowed_ptr(task, cs->effective_cpus);
979 css_task_iter_end(&it);
983 * compute_effective_cpumask - Compute the effective cpumask of the cpuset
984 * @new_cpus: the temp variable for the new effective_cpus mask
985 * @cs: the cpuset the need to recompute the new effective_cpus mask
986 * @parent: the parent cpuset
988 * If the parent has subpartition CPUs, include them in the list of
989 * allowable CPUs in computing the new effective_cpus mask.
991 static void compute_effective_cpumask(struct cpumask *new_cpus,
992 struct cpuset *cs, struct cpuset *parent)
994 if (parent->nr_subparts_cpus) {
995 cpumask_or(new_cpus, parent->effective_cpus,
996 parent->subparts_cpus);
997 cpumask_and(new_cpus, new_cpus, cs->cpus_allowed);
999 cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
1004 * Commands for update_parent_subparts_cpumask
1007 partcmd_enable, /* Enable partition root */
1008 partcmd_disable, /* Disable partition root */
1009 partcmd_update, /* Update parent's subparts_cpus */
1013 * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
1014 * @cpuset: The cpuset that requests change in partition root state
1015 * @cmd: Partition root state change command
1016 * @newmask: Optional new cpumask for partcmd_update
1017 * @tmp: Temporary addmask and delmask
1018 * Return: 0, 1 or an error code
1020 * For partcmd_enable, the cpuset is being transformed from a non-partition
1021 * root to a partition root. The cpus_allowed mask of the given cpuset will
1022 * be put into parent's subparts_cpus and taken away from parent's
1023 * effective_cpus. The function will return 0 if all the CPUs listed in
1024 * cpus_allowed can be granted or an error code will be returned.
1026 * For partcmd_disable, the cpuset is being transofrmed from a partition
1027 * root back to a non-partition root. any CPUs in cpus_allowed that are in
1028 * parent's subparts_cpus will be taken away from that cpumask and put back
1029 * into parent's effective_cpus. 0 should always be returned.
1031 * For partcmd_update, if the optional newmask is specified, the cpu
1032 * list is to be changed from cpus_allowed to newmask. Otherwise,
1033 * cpus_allowed is assumed to remain the same. The cpuset should either
1034 * be a partition root or an invalid partition root. The partition root
1035 * state may change if newmask is NULL and none of the requested CPUs can
1036 * be granted by the parent. The function will return 1 if changes to
1037 * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
1038 * Error code should only be returned when newmask is non-NULL.
1040 * The partcmd_enable and partcmd_disable commands are used by
1041 * update_prstate(). The partcmd_update command is used by
1042 * update_cpumasks_hier() with newmask NULL and update_cpumask() with
1045 * The checking is more strict when enabling partition root than the
1046 * other two commands.
1048 * Because of the implicit cpu exclusive nature of a partition root,
1049 * cpumask changes that violates the cpu exclusivity rule will not be
1050 * permitted when checked by validate_change(). The validate_change()
1051 * function will also prevent any changes to the cpu list if it is not
1052 * a superset of children's cpu lists.
1054 static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
1055 struct cpumask *newmask,
1056 struct tmpmasks *tmp)
1058 struct cpuset *parent = parent_cs(cpuset);
1059 int adding; /* Moving cpus from effective_cpus to subparts_cpus */
1060 int deleting; /* Moving cpus from subparts_cpus to effective_cpus */
1061 bool part_error = false; /* Partition error? */
1063 lockdep_assert_held(&cpuset_mutex);
1066 * The parent must be a partition root.
1067 * The new cpumask, if present, or the current cpus_allowed must
1070 if (!is_partition_root(parent) ||
1071 (newmask && cpumask_empty(newmask)) ||
1072 (!newmask && cpumask_empty(cpuset->cpus_allowed)))
1076 * Enabling/disabling partition root is not allowed if there are
1079 if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css))
1083 * Enabling partition root is not allowed if not all the CPUs
1084 * can be granted from parent's effective_cpus or at least one
1085 * CPU will be left after that.
1087 if ((cmd == partcmd_enable) &&
1088 (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) ||
1089 cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus)))
1093 * A cpumask update cannot make parent's effective_cpus become empty.
1095 adding = deleting = false;
1096 if (cmd == partcmd_enable) {
1097 cpumask_copy(tmp->addmask, cpuset->cpus_allowed);
1099 } else if (cmd == partcmd_disable) {
1100 deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
1101 parent->subparts_cpus);
1102 } else if (newmask) {
1104 * partcmd_update with newmask:
1106 * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
1107 * addmask = newmask & parent->effective_cpus
1108 * & ~parent->subparts_cpus
1110 cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask);
1111 deleting = cpumask_and(tmp->delmask, tmp->delmask,
1112 parent->subparts_cpus);
1114 cpumask_and(tmp->addmask, newmask, parent->effective_cpus);
1115 adding = cpumask_andnot(tmp->addmask, tmp->addmask,
1116 parent->subparts_cpus);
1118 * Return error if the new effective_cpus could become empty.
1120 if (adding && !deleting &&
1121 cpumask_equal(parent->effective_cpus, tmp->addmask))
1125 * partcmd_update w/o newmask:
1127 * addmask = cpus_allowed & parent->effectiveb_cpus
1129 * Note that parent's subparts_cpus may have been
1130 * pre-shrunk in case there is a change in the cpu list.
1131 * So no deletion is needed.
1133 adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed,
1134 parent->effective_cpus);
1135 part_error = cpumask_equal(tmp->addmask,
1136 parent->effective_cpus);
1139 if (cmd == partcmd_update) {
1140 int prev_prs = cpuset->partition_root_state;
1143 * Check for possible transition between PRS_ENABLED
1146 switch (cpuset->partition_root_state) {
1149 cpuset->partition_root_state = PRS_ERROR;
1153 cpuset->partition_root_state = PRS_ENABLED;
1157 * Set part_error if previously in invalid state.
1159 part_error = (prev_prs == PRS_ERROR);
1162 if (!part_error && (cpuset->partition_root_state == PRS_ERROR))
1163 return 0; /* Nothing need to be done */
1165 if (cpuset->partition_root_state == PRS_ERROR) {
1167 * Remove all its cpus from parent's subparts_cpus.
1170 deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
1171 parent->subparts_cpus);
1174 if (!adding && !deleting)
1178 * Change the parent's subparts_cpus.
1179 * Newly added CPUs will be removed from effective_cpus and
1180 * newly deleted ones will be added back to effective_cpus.
1182 spin_lock_irq(&callback_lock);
1184 cpumask_or(parent->subparts_cpus,
1185 parent->subparts_cpus, tmp->addmask);
1186 cpumask_andnot(parent->effective_cpus,
1187 parent->effective_cpus, tmp->addmask);
1190 cpumask_andnot(parent->subparts_cpus,
1191 parent->subparts_cpus, tmp->delmask);
1192 cpumask_or(parent->effective_cpus,
1193 parent->effective_cpus, tmp->delmask);
1196 parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
1197 spin_unlock_irq(&callback_lock);
1199 return cmd == partcmd_update;
1203 * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
1204 * @cs: the cpuset to consider
1205 * @tmp: temp variables for calculating effective_cpus & partition setup
1207 * When congifured cpumask is changed, the effective cpumasks of this cpuset
1208 * and all its descendants need to be updated.
1210 * On legacy hierachy, effective_cpus will be the same with cpu_allowed.
1212 * Called with cpuset_mutex held
1214 static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
1217 struct cgroup_subsys_state *pos_css;
1218 bool need_rebuild_sched_domains = false;
1221 cpuset_for_each_descendant_pre(cp, pos_css, cs) {
1222 struct cpuset *parent = parent_cs(cp);
1224 compute_effective_cpumask(tmp->new_cpus, cp, parent);
1227 * If it becomes empty, inherit the effective mask of the
1228 * parent, which is guaranteed to have some CPUs.
1230 if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus))
1231 cpumask_copy(tmp->new_cpus, parent->effective_cpus);
1234 * Skip the whole subtree if the cpumask remains the same
1235 * and has no partition root state.
1237 if (!cp->partition_root_state &&
1238 cpumask_equal(tmp->new_cpus, cp->effective_cpus)) {
1239 pos_css = css_rightmost_descendant(pos_css);
1244 * update_parent_subparts_cpumask() should have been called
1245 * for cs already in update_cpumask(). We should also call
1246 * update_tasks_cpumask() again for tasks in the parent
1247 * cpuset if the parent's subparts_cpus changes.
1249 if ((cp != cs) && cp->partition_root_state) {
1250 switch (parent->partition_root_state) {
1253 * If parent is not a partition root or an
1254 * invalid partition root, clear the state
1255 * state and the CS_CPU_EXCLUSIVE flag.
1257 WARN_ON_ONCE(cp->partition_root_state
1259 cp->partition_root_state = 0;
1262 * clear_bit() is an atomic operation and
1263 * readers aren't interested in the state
1264 * of CS_CPU_EXCLUSIVE anyway. So we can
1265 * just update the flag without holding
1266 * the callback_lock.
1268 clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
1272 if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
1273 update_tasks_cpumask(parent);
1278 * When parent is invalid, it has to be too.
1280 cp->partition_root_state = PRS_ERROR;
1281 if (cp->nr_subparts_cpus) {
1282 cp->nr_subparts_cpus = 0;
1283 cpumask_clear(cp->subparts_cpus);
1289 if (!css_tryget_online(&cp->css))
1293 spin_lock_irq(&callback_lock);
1295 cpumask_copy(cp->effective_cpus, tmp->new_cpus);
1296 if (cp->nr_subparts_cpus &&
1297 (cp->partition_root_state != PRS_ENABLED)) {
1298 cp->nr_subparts_cpus = 0;
1299 cpumask_clear(cp->subparts_cpus);
1300 } else if (cp->nr_subparts_cpus) {
1302 * Make sure that effective_cpus & subparts_cpus
1303 * are mutually exclusive.
1305 * In the unlikely event that effective_cpus
1306 * becomes empty. we clear cp->nr_subparts_cpus and
1307 * let its child partition roots to compete for
1310 cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
1312 if (cpumask_empty(cp->effective_cpus)) {
1313 cpumask_copy(cp->effective_cpus, tmp->new_cpus);
1314 cpumask_clear(cp->subparts_cpus);
1315 cp->nr_subparts_cpus = 0;
1316 } else if (!cpumask_subset(cp->subparts_cpus,
1318 cpumask_andnot(cp->subparts_cpus,
1319 cp->subparts_cpus, tmp->new_cpus);
1320 cp->nr_subparts_cpus
1321 = cpumask_weight(cp->subparts_cpus);
1324 spin_unlock_irq(&callback_lock);
1326 WARN_ON(!is_in_v2_mode() &&
1327 !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
1329 update_tasks_cpumask(cp);
1332 * If the effective cpumask of any non-empty cpuset is changed,
1333 * we need to rebuild sched domains.
1335 if (!cpumask_empty(cp->cpus_allowed) &&
1336 is_sched_load_balance(cp))
1337 need_rebuild_sched_domains = true;
1344 if (need_rebuild_sched_domains)
1345 rebuild_sched_domains_locked();
1349 * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
1350 * @cs: the cpuset to consider
1351 * @trialcs: trial cpuset
1352 * @buf: buffer of cpu numbers written to this cpuset
1354 static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
1358 struct tmpmasks tmp;
1360 /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
1361 if (cs == &top_cpuset)
1365 * An empty cpus_allowed is ok only if the cpuset has no tasks.
1366 * Since cpulist_parse() fails on an empty mask, we special case
1367 * that parsing. The validate_change() call ensures that cpusets
1368 * with tasks have cpus.
1371 cpumask_clear(trialcs->cpus_allowed);
1373 retval = cpulist_parse(buf, trialcs->cpus_allowed);
1377 if (!cpumask_subset(trialcs->cpus_allowed,
1378 top_cpuset.cpus_allowed))
1382 /* Nothing to do if the cpus didn't change */
1383 if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
1386 retval = validate_change(cs, trialcs);
1390 #ifdef CONFIG_CPUMASK_OFFSTACK
1392 * Use the cpumasks in trialcs for tmpmasks when they are pointers
1393 * to allocated cpumasks.
1395 tmp.addmask = trialcs->subparts_cpus;
1396 tmp.delmask = trialcs->effective_cpus;
1397 tmp.new_cpus = trialcs->cpus_allowed;
1400 if (cs->partition_root_state) {
1401 /* Cpumask of a partition root cannot be empty */
1402 if (cpumask_empty(trialcs->cpus_allowed))
1404 if (update_parent_subparts_cpumask(cs, partcmd_update,
1405 trialcs->cpus_allowed, &tmp) < 0)
1409 spin_lock_irq(&callback_lock);
1410 cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
1413 * Make sure that subparts_cpus is a subset of cpus_allowed.
1415 if (cs->nr_subparts_cpus) {
1416 cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
1418 cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
1420 spin_unlock_irq(&callback_lock);
1422 update_cpumasks_hier(cs, &tmp);
1427 * Migrate memory region from one set of nodes to another. This is
1428 * performed asynchronously as it can be called from process migration path
1429 * holding locks involved in process management. All mm migrations are
1430 * performed in the queued order and can be waited for by flushing
1431 * cpuset_migrate_mm_wq.
1434 struct cpuset_migrate_mm_work {
1435 struct work_struct work;
1436 struct mm_struct *mm;
1441 static void cpuset_migrate_mm_workfn(struct work_struct *work)
1443 struct cpuset_migrate_mm_work *mwork =
1444 container_of(work, struct cpuset_migrate_mm_work, work);
1446 /* on a wq worker, no need to worry about %current's mems_allowed */
1447 do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
1452 static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
1453 const nodemask_t *to)
1455 struct cpuset_migrate_mm_work *mwork;
1457 mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
1460 mwork->from = *from;
1462 INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
1463 queue_work(cpuset_migrate_mm_wq, &mwork->work);
1469 static void cpuset_post_attach(void)
1471 flush_workqueue(cpuset_migrate_mm_wq);
1475 * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
1476 * @tsk: the task to change
1477 * @newmems: new nodes that the task will be set
1479 * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
1480 * and rebind an eventual tasks' mempolicy. If the task is allocating in
1481 * parallel, it might temporarily see an empty intersection, which results in
1482 * a seqlock check and retry before OOM or allocation failure.
1484 static void cpuset_change_task_nodemask(struct task_struct *tsk,
1485 nodemask_t *newmems)
1489 local_irq_disable();
1490 write_seqcount_begin(&tsk->mems_allowed_seq);
1492 nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
1493 mpol_rebind_task(tsk, newmems);
1494 tsk->mems_allowed = *newmems;
1496 write_seqcount_end(&tsk->mems_allowed_seq);
1502 static void *cpuset_being_rebound;
1505 * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
1506 * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
1508 * Iterate through each task of @cs updating its mems_allowed to the
1509 * effective cpuset's. As this function is called with cpuset_mutex held,
1510 * cpuset membership stays stable.
1512 static void update_tasks_nodemask(struct cpuset *cs)
1514 static nodemask_t newmems; /* protected by cpuset_mutex */
1515 struct css_task_iter it;
1516 struct task_struct *task;
1518 cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
1520 guarantee_online_mems(cs, &newmems);
1523 * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
1524 * take while holding tasklist_lock. Forks can happen - the
1525 * mpol_dup() cpuset_being_rebound check will catch such forks,
1526 * and rebind their vma mempolicies too. Because we still hold
1527 * the global cpuset_mutex, we know that no other rebind effort
1528 * will be contending for the global variable cpuset_being_rebound.
1529 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
1530 * is idempotent. Also migrate pages in each mm to new nodes.
1532 css_task_iter_start(&cs->css, 0, &it);
1533 while ((task = css_task_iter_next(&it))) {
1534 struct mm_struct *mm;
1537 cpuset_change_task_nodemask(task, &newmems);
1539 mm = get_task_mm(task);
1543 migrate = is_memory_migrate(cs);
1545 mpol_rebind_mm(mm, &cs->mems_allowed);
1547 cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
1551 css_task_iter_end(&it);
1554 * All the tasks' nodemasks have been updated, update
1555 * cs->old_mems_allowed.
1557 cs->old_mems_allowed = newmems;
1559 /* We're done rebinding vmas to this cpuset's new mems_allowed. */
1560 cpuset_being_rebound = NULL;
1564 * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
1565 * @cs: the cpuset to consider
1566 * @new_mems: a temp variable for calculating new effective_mems
1568 * When configured nodemask is changed, the effective nodemasks of this cpuset
1569 * and all its descendants need to be updated.
1571 * On legacy hiearchy, effective_mems will be the same with mems_allowed.
1573 * Called with cpuset_mutex held
1575 static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
1578 struct cgroup_subsys_state *pos_css;
1581 cpuset_for_each_descendant_pre(cp, pos_css, cs) {
1582 struct cpuset *parent = parent_cs(cp);
1584 nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
1587 * If it becomes empty, inherit the effective mask of the
1588 * parent, which is guaranteed to have some MEMs.
1590 if (is_in_v2_mode() && nodes_empty(*new_mems))
1591 *new_mems = parent->effective_mems;
1593 /* Skip the whole subtree if the nodemask remains the same. */
1594 if (nodes_equal(*new_mems, cp->effective_mems)) {
1595 pos_css = css_rightmost_descendant(pos_css);
1599 if (!css_tryget_online(&cp->css))
1603 spin_lock_irq(&callback_lock);
1604 cp->effective_mems = *new_mems;
1605 spin_unlock_irq(&callback_lock);
1607 WARN_ON(!is_in_v2_mode() &&
1608 !nodes_equal(cp->mems_allowed, cp->effective_mems));
1610 update_tasks_nodemask(cp);
1619 * Handle user request to change the 'mems' memory placement
1620 * of a cpuset. Needs to validate the request, update the
1621 * cpusets mems_allowed, and for each task in the cpuset,
1622 * update mems_allowed and rebind task's mempolicy and any vma
1623 * mempolicies and if the cpuset is marked 'memory_migrate',
1624 * migrate the tasks pages to the new memory.
1626 * Call with cpuset_mutex held. May take callback_lock during call.
1627 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
1628 * lock each such tasks mm->mmap_sem, scan its vma's and rebind
1629 * their mempolicies to the cpusets new mems_allowed.
1631 static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
1637 * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
1640 if (cs == &top_cpuset) {
1646 * An empty mems_allowed is ok iff there are no tasks in the cpuset.
1647 * Since nodelist_parse() fails on an empty mask, we special case
1648 * that parsing. The validate_change() call ensures that cpusets
1649 * with tasks have memory.
1652 nodes_clear(trialcs->mems_allowed);
1654 retval = nodelist_parse(buf, trialcs->mems_allowed);
1658 if (!nodes_subset(trialcs->mems_allowed,
1659 top_cpuset.mems_allowed)) {
1665 if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
1666 retval = 0; /* Too easy - nothing to do */
1669 retval = validate_change(cs, trialcs);
1673 spin_lock_irq(&callback_lock);
1674 cs->mems_allowed = trialcs->mems_allowed;
1675 spin_unlock_irq(&callback_lock);
1677 /* use trialcs->mems_allowed as a temp variable */
1678 update_nodemasks_hier(cs, &trialcs->mems_allowed);
1683 bool current_cpuset_is_being_rebound(void)
1688 ret = task_cs(current) == cpuset_being_rebound;
1694 static int update_relax_domain_level(struct cpuset *cs, s64 val)
1697 if (val < -1 || val >= sched_domain_level_max)
1701 if (val != cs->relax_domain_level) {
1702 cs->relax_domain_level = val;
1703 if (!cpumask_empty(cs->cpus_allowed) &&
1704 is_sched_load_balance(cs))
1705 rebuild_sched_domains_locked();
1712 * update_tasks_flags - update the spread flags of tasks in the cpuset.
1713 * @cs: the cpuset in which each task's spread flags needs to be changed
1715 * Iterate through each task of @cs updating its spread flags. As this
1716 * function is called with cpuset_mutex held, cpuset membership stays
1719 static void update_tasks_flags(struct cpuset *cs)
1721 struct css_task_iter it;
1722 struct task_struct *task;
1724 css_task_iter_start(&cs->css, 0, &it);
1725 while ((task = css_task_iter_next(&it)))
1726 cpuset_update_task_spread_flag(cs, task);
1727 css_task_iter_end(&it);
1731 * update_flag - read a 0 or a 1 in a file and update associated flag
1732 * bit: the bit to update (see cpuset_flagbits_t)
1733 * cs: the cpuset to update
1734 * turning_on: whether the flag is being set or cleared
1736 * Call with cpuset_mutex held.
1739 static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
1742 struct cpuset *trialcs;
1743 int balance_flag_changed;
1744 int spread_flag_changed;
1747 trialcs = alloc_trial_cpuset(cs);
1752 set_bit(bit, &trialcs->flags);
1754 clear_bit(bit, &trialcs->flags);
1756 err = validate_change(cs, trialcs);
1760 balance_flag_changed = (is_sched_load_balance(cs) !=
1761 is_sched_load_balance(trialcs));
1763 spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
1764 || (is_spread_page(cs) != is_spread_page(trialcs)));
1766 spin_lock_irq(&callback_lock);
1767 cs->flags = trialcs->flags;
1768 spin_unlock_irq(&callback_lock);
1770 if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
1771 rebuild_sched_domains_locked();
1773 if (spread_flag_changed)
1774 update_tasks_flags(cs);
1776 free_cpuset(trialcs);
1781 * update_prstate - update partititon_root_state
1782 * cs: the cpuset to update
1783 * val: 0 - disabled, 1 - enabled
1785 * Call with cpuset_mutex held.
1787 static int update_prstate(struct cpuset *cs, int val)
1790 struct cpuset *parent = parent_cs(cs);
1791 struct tmpmasks tmp;
1793 if ((val != 0) && (val != 1))
1795 if (val == cs->partition_root_state)
1799 * Cannot force a partial or invalid partition root to a full
1802 if (val && cs->partition_root_state)
1805 if (alloc_cpumasks(NULL, &tmp))
1809 if (!cs->partition_root_state) {
1811 * Turning on partition root requires setting the
1812 * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
1815 if (cpumask_empty(cs->cpus_allowed))
1818 err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
1822 err = update_parent_subparts_cpumask(cs, partcmd_enable,
1825 update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1828 cs->partition_root_state = PRS_ENABLED;
1831 * Turning off partition root will clear the
1832 * CS_CPU_EXCLUSIVE bit.
1834 if (cs->partition_root_state == PRS_ERROR) {
1835 cs->partition_root_state = 0;
1836 update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1841 err = update_parent_subparts_cpumask(cs, partcmd_disable,
1846 cs->partition_root_state = 0;
1848 /* Turning off CS_CPU_EXCLUSIVE will not return error */
1849 update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1853 * Update cpumask of parent's tasks except when it is the top
1854 * cpuset as some system daemons cannot be mapped to other CPUs.
1856 if (parent != &top_cpuset)
1857 update_tasks_cpumask(parent);
1859 rebuild_sched_domains_locked();
1861 free_cpumasks(NULL, &tmp);
1866 * Frequency meter - How fast is some event occurring?
1868 * These routines manage a digitally filtered, constant time based,
1869 * event frequency meter. There are four routines:
1870 * fmeter_init() - initialize a frequency meter.
1871 * fmeter_markevent() - called each time the event happens.
1872 * fmeter_getrate() - returns the recent rate of such events.
1873 * fmeter_update() - internal routine used to update fmeter.
1875 * A common data structure is passed to each of these routines,
1876 * which is used to keep track of the state required to manage the
1877 * frequency meter and its digital filter.
1879 * The filter works on the number of events marked per unit time.
1880 * The filter is single-pole low-pass recursive (IIR). The time unit
1881 * is 1 second. Arithmetic is done using 32-bit integers scaled to
1882 * simulate 3 decimal digits of precision (multiplied by 1000).
1884 * With an FM_COEF of 933, and a time base of 1 second, the filter
1885 * has a half-life of 10 seconds, meaning that if the events quit
1886 * happening, then the rate returned from the fmeter_getrate()
1887 * will be cut in half each 10 seconds, until it converges to zero.
1889 * It is not worth doing a real infinitely recursive filter. If more
1890 * than FM_MAXTICKS ticks have elapsed since the last filter event,
1891 * just compute FM_MAXTICKS ticks worth, by which point the level
1894 * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
1895 * arithmetic overflow in the fmeter_update() routine.
1897 * Given the simple 32 bit integer arithmetic used, this meter works
1898 * best for reporting rates between one per millisecond (msec) and
1899 * one per 32 (approx) seconds. At constant rates faster than one
1900 * per msec it maxes out at values just under 1,000,000. At constant
1901 * rates between one per msec, and one per second it will stabilize
1902 * to a value N*1000, where N is the rate of events per second.
1903 * At constant rates between one per second and one per 32 seconds,
1904 * it will be choppy, moving up on the seconds that have an event,
1905 * and then decaying until the next event. At rates slower than
1906 * about one in 32 seconds, it decays all the way back to zero between
1910 #define FM_COEF 933 /* coefficient for half-life of 10 secs */
1911 #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */
1912 #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
1913 #define FM_SCALE 1000 /* faux fixed point scale */
1915 /* Initialize a frequency meter */
1916 static void fmeter_init(struct fmeter *fmp)
1921 spin_lock_init(&fmp->lock);
1924 /* Internal meter update - process cnt events and update value */
1925 static void fmeter_update(struct fmeter *fmp)
1930 now = ktime_get_seconds();
1931 ticks = now - fmp->time;
1936 ticks = min(FM_MAXTICKS, ticks);
1938 fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
1941 fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
1945 /* Process any previous ticks, then bump cnt by one (times scale). */
1946 static void fmeter_markevent(struct fmeter *fmp)
1948 spin_lock(&fmp->lock);
1950 fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
1951 spin_unlock(&fmp->lock);
1954 /* Process any previous ticks, then return current value. */
1955 static int fmeter_getrate(struct fmeter *fmp)
1959 spin_lock(&fmp->lock);
1962 spin_unlock(&fmp->lock);
1966 static struct cpuset *cpuset_attach_old_cs;
1968 /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
1969 static int cpuset_can_attach(struct cgroup_taskset *tset)
1971 struct cgroup_subsys_state *css;
1973 struct task_struct *task;
1976 /* used later by cpuset_attach() */
1977 cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
1980 mutex_lock(&cpuset_mutex);
1982 /* allow moving tasks into an empty cpuset if on default hierarchy */
1984 if (!is_in_v2_mode() &&
1985 (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
1988 cgroup_taskset_for_each(task, css, tset) {
1989 ret = task_can_attach(task, cs->cpus_allowed);
1992 ret = security_task_setscheduler(task);
1998 * Mark attach is in progress. This makes validate_change() fail
1999 * changes which zero cpus/mems_allowed.
2001 cs->attach_in_progress++;
2004 mutex_unlock(&cpuset_mutex);
2008 static void cpuset_cancel_attach(struct cgroup_taskset *tset)
2010 struct cgroup_subsys_state *css;
2013 cgroup_taskset_first(tset, &css);
2016 mutex_lock(&cpuset_mutex);
2017 css_cs(css)->attach_in_progress--;
2018 mutex_unlock(&cpuset_mutex);
2022 * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach()
2023 * but we can't allocate it dynamically there. Define it global and
2024 * allocate from cpuset_init().
2026 static cpumask_var_t cpus_attach;
2028 static void cpuset_attach(struct cgroup_taskset *tset)
2030 /* static buf protected by cpuset_mutex */
2031 static nodemask_t cpuset_attach_nodemask_to;
2032 struct task_struct *task;
2033 struct task_struct *leader;
2034 struct cgroup_subsys_state *css;
2036 struct cpuset *oldcs = cpuset_attach_old_cs;
2038 cgroup_taskset_first(tset, &css);
2041 mutex_lock(&cpuset_mutex);
2043 /* prepare for attach */
2044 if (cs == &top_cpuset)
2045 cpumask_copy(cpus_attach, cpu_possible_mask);
2047 guarantee_online_cpus(cs, cpus_attach);
2049 guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
2051 cgroup_taskset_for_each(task, css, tset) {
2053 * can_attach beforehand should guarantee that this doesn't
2054 * fail. TODO: have a better way to handle failure here
2056 WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
2058 cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
2059 cpuset_update_task_spread_flag(cs, task);
2063 * Change mm for all threadgroup leaders. This is expensive and may
2064 * sleep and should be moved outside migration path proper.
2066 cpuset_attach_nodemask_to = cs->effective_mems;
2067 cgroup_taskset_for_each_leader(leader, css, tset) {
2068 struct mm_struct *mm = get_task_mm(leader);
2071 mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
2074 * old_mems_allowed is the same with mems_allowed
2075 * here, except if this task is being moved
2076 * automatically due to hotplug. In that case
2077 * @mems_allowed has been updated and is empty, so
2078 * @old_mems_allowed is the right nodesets that we
2081 if (is_memory_migrate(cs))
2082 cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
2083 &cpuset_attach_nodemask_to);
2089 cs->old_mems_allowed = cpuset_attach_nodemask_to;
2091 cs->attach_in_progress--;
2092 if (!cs->attach_in_progress)
2093 wake_up(&cpuset_attach_wq);
2095 mutex_unlock(&cpuset_mutex);
2098 /* The various types of files and directories in a cpuset file system */
2101 FILE_MEMORY_MIGRATE,
2104 FILE_EFFECTIVE_CPULIST,
2105 FILE_EFFECTIVE_MEMLIST,
2109 FILE_SCHED_LOAD_BALANCE,
2110 FILE_PARTITION_ROOT,
2111 FILE_SCHED_RELAX_DOMAIN_LEVEL,
2112 FILE_MEMORY_PRESSURE_ENABLED,
2113 FILE_MEMORY_PRESSURE,
2116 } cpuset_filetype_t;
2118 static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
2121 struct cpuset *cs = css_cs(css);
2122 cpuset_filetype_t type = cft->private;
2125 mutex_lock(&cpuset_mutex);
2126 if (!is_cpuset_online(cs)) {
2132 case FILE_CPU_EXCLUSIVE:
2133 retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
2135 case FILE_MEM_EXCLUSIVE:
2136 retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
2138 case FILE_MEM_HARDWALL:
2139 retval = update_flag(CS_MEM_HARDWALL, cs, val);
2141 case FILE_SCHED_LOAD_BALANCE:
2142 retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
2144 case FILE_MEMORY_MIGRATE:
2145 retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
2147 case FILE_MEMORY_PRESSURE_ENABLED:
2148 cpuset_memory_pressure_enabled = !!val;
2150 case FILE_SPREAD_PAGE:
2151 retval = update_flag(CS_SPREAD_PAGE, cs, val);
2153 case FILE_SPREAD_SLAB:
2154 retval = update_flag(CS_SPREAD_SLAB, cs, val);
2161 mutex_unlock(&cpuset_mutex);
2165 static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
2168 struct cpuset *cs = css_cs(css);
2169 cpuset_filetype_t type = cft->private;
2170 int retval = -ENODEV;
2172 mutex_lock(&cpuset_mutex);
2173 if (!is_cpuset_online(cs))
2177 case FILE_SCHED_RELAX_DOMAIN_LEVEL:
2178 retval = update_relax_domain_level(cs, val);
2180 case FILE_PARTITION_ROOT:
2181 retval = update_prstate(cs, val);
2188 mutex_unlock(&cpuset_mutex);
2193 * Common handling for a write to a "cpus" or "mems" file.
2195 static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
2196 char *buf, size_t nbytes, loff_t off)
2198 struct cpuset *cs = css_cs(of_css(of));
2199 struct cpuset *trialcs;
2200 int retval = -ENODEV;
2202 buf = strstrip(buf);
2205 * CPU or memory hotunplug may leave @cs w/o any execution
2206 * resources, in which case the hotplug code asynchronously updates
2207 * configuration and transfers all tasks to the nearest ancestor
2208 * which can execute.
2210 * As writes to "cpus" or "mems" may restore @cs's execution
2211 * resources, wait for the previously scheduled operations before
2212 * proceeding, so that we don't end up keep removing tasks added
2213 * after execution capability is restored.
2215 * cpuset_hotplug_work calls back into cgroup core via
2216 * cgroup_transfer_tasks() and waiting for it from a cgroupfs
2217 * operation like this one can lead to a deadlock through kernfs
2218 * active_ref protection. Let's break the protection. Losing the
2219 * protection is okay as we check whether @cs is online after
2220 * grabbing cpuset_mutex anyway. This only happens on the legacy
2224 kernfs_break_active_protection(of->kn);
2225 flush_work(&cpuset_hotplug_work);
2227 mutex_lock(&cpuset_mutex);
2228 if (!is_cpuset_online(cs))
2231 trialcs = alloc_trial_cpuset(cs);
2237 switch (of_cft(of)->private) {
2239 retval = update_cpumask(cs, trialcs, buf);
2242 retval = update_nodemask(cs, trialcs, buf);
2249 free_cpuset(trialcs);
2251 mutex_unlock(&cpuset_mutex);
2252 kernfs_unbreak_active_protection(of->kn);
2254 flush_workqueue(cpuset_migrate_mm_wq);
2255 return retval ?: nbytes;
2259 * These ascii lists should be read in a single call, by using a user
2260 * buffer large enough to hold the entire map. If read in smaller
2261 * chunks, there is no guarantee of atomicity. Since the display format
2262 * used, list of ranges of sequential numbers, is variable length,
2263 * and since these maps can change value dynamically, one could read
2264 * gibberish by doing partial reads while a list was changing.
2266 static int cpuset_common_seq_show(struct seq_file *sf, void *v)
2268 struct cpuset *cs = css_cs(seq_css(sf));
2269 cpuset_filetype_t type = seq_cft(sf)->private;
2272 spin_lock_irq(&callback_lock);
2276 seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed));
2279 seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
2281 case FILE_EFFECTIVE_CPULIST:
2282 seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
2284 case FILE_EFFECTIVE_MEMLIST:
2285 seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
2291 spin_unlock_irq(&callback_lock);
2295 static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
2297 struct cpuset *cs = css_cs(css);
2298 cpuset_filetype_t type = cft->private;
2300 case FILE_CPU_EXCLUSIVE:
2301 return is_cpu_exclusive(cs);
2302 case FILE_MEM_EXCLUSIVE:
2303 return is_mem_exclusive(cs);
2304 case FILE_MEM_HARDWALL:
2305 return is_mem_hardwall(cs);
2306 case FILE_SCHED_LOAD_BALANCE:
2307 return is_sched_load_balance(cs);
2308 case FILE_MEMORY_MIGRATE:
2309 return is_memory_migrate(cs);
2310 case FILE_MEMORY_PRESSURE_ENABLED:
2311 return cpuset_memory_pressure_enabled;
2312 case FILE_MEMORY_PRESSURE:
2313 return fmeter_getrate(&cs->fmeter);
2314 case FILE_SPREAD_PAGE:
2315 return is_spread_page(cs);
2316 case FILE_SPREAD_SLAB:
2317 return is_spread_slab(cs);
2322 /* Unreachable but makes gcc happy */
2326 static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
2328 struct cpuset *cs = css_cs(css);
2329 cpuset_filetype_t type = cft->private;
2331 case FILE_SCHED_RELAX_DOMAIN_LEVEL:
2332 return cs->relax_domain_level;
2333 case FILE_PARTITION_ROOT:
2334 return cs->partition_root_state;
2339 /* Unrechable but makes gcc happy */
2344 * for the common functions, 'private' gives the type of file
2347 static struct cftype legacy_files[] = {
2350 .seq_show = cpuset_common_seq_show,
2351 .write = cpuset_write_resmask,
2352 .max_write_len = (100U + 6 * NR_CPUS),
2353 .private = FILE_CPULIST,
2358 .seq_show = cpuset_common_seq_show,
2359 .write = cpuset_write_resmask,
2360 .max_write_len = (100U + 6 * MAX_NUMNODES),
2361 .private = FILE_MEMLIST,
2365 .name = "effective_cpus",
2366 .seq_show = cpuset_common_seq_show,
2367 .private = FILE_EFFECTIVE_CPULIST,
2371 .name = "effective_mems",
2372 .seq_show = cpuset_common_seq_show,
2373 .private = FILE_EFFECTIVE_MEMLIST,
2377 .name = "cpu_exclusive",
2378 .read_u64 = cpuset_read_u64,
2379 .write_u64 = cpuset_write_u64,
2380 .private = FILE_CPU_EXCLUSIVE,
2384 .name = "mem_exclusive",
2385 .read_u64 = cpuset_read_u64,
2386 .write_u64 = cpuset_write_u64,
2387 .private = FILE_MEM_EXCLUSIVE,
2391 .name = "mem_hardwall",
2392 .read_u64 = cpuset_read_u64,
2393 .write_u64 = cpuset_write_u64,
2394 .private = FILE_MEM_HARDWALL,
2398 .name = "sched_load_balance",
2399 .read_u64 = cpuset_read_u64,
2400 .write_u64 = cpuset_write_u64,
2401 .private = FILE_SCHED_LOAD_BALANCE,
2405 .name = "sched_relax_domain_level",
2406 .read_s64 = cpuset_read_s64,
2407 .write_s64 = cpuset_write_s64,
2408 .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
2412 .name = "memory_migrate",
2413 .read_u64 = cpuset_read_u64,
2414 .write_u64 = cpuset_write_u64,
2415 .private = FILE_MEMORY_MIGRATE,
2419 .name = "memory_pressure",
2420 .read_u64 = cpuset_read_u64,
2421 .private = FILE_MEMORY_PRESSURE,
2425 .name = "memory_spread_page",
2426 .read_u64 = cpuset_read_u64,
2427 .write_u64 = cpuset_write_u64,
2428 .private = FILE_SPREAD_PAGE,
2432 .name = "memory_spread_slab",
2433 .read_u64 = cpuset_read_u64,
2434 .write_u64 = cpuset_write_u64,
2435 .private = FILE_SPREAD_SLAB,
2439 .name = "memory_pressure_enabled",
2440 .flags = CFTYPE_ONLY_ON_ROOT,
2441 .read_u64 = cpuset_read_u64,
2442 .write_u64 = cpuset_write_u64,
2443 .private = FILE_MEMORY_PRESSURE_ENABLED,
2450 * This is currently a minimal set for the default hierarchy. It can be
2451 * expanded later on by migrating more features and control files from v1.
2453 static struct cftype dfl_files[] = {
2456 .seq_show = cpuset_common_seq_show,
2457 .write = cpuset_write_resmask,
2458 .max_write_len = (100U + 6 * NR_CPUS),
2459 .private = FILE_CPULIST,
2460 .flags = CFTYPE_NOT_ON_ROOT,
2465 .seq_show = cpuset_common_seq_show,
2466 .write = cpuset_write_resmask,
2467 .max_write_len = (100U + 6 * MAX_NUMNODES),
2468 .private = FILE_MEMLIST,
2469 .flags = CFTYPE_NOT_ON_ROOT,
2473 .name = "cpus.effective",
2474 .seq_show = cpuset_common_seq_show,
2475 .private = FILE_EFFECTIVE_CPULIST,
2476 .flags = CFTYPE_NOT_ON_ROOT,
2480 .name = "mems.effective",
2481 .seq_show = cpuset_common_seq_show,
2482 .private = FILE_EFFECTIVE_MEMLIST,
2483 .flags = CFTYPE_NOT_ON_ROOT,
2487 .name = "sched.partition",
2488 .read_s64 = cpuset_read_s64,
2489 .write_s64 = cpuset_write_s64,
2490 .private = FILE_PARTITION_ROOT,
2491 .flags = CFTYPE_NOT_ON_ROOT,
2499 * cpuset_css_alloc - allocate a cpuset css
2500 * cgrp: control group that the new cpuset will be part of
2503 static struct cgroup_subsys_state *
2504 cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
2509 return &top_cpuset.css;
2511 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
2513 return ERR_PTR(-ENOMEM);
2515 if (alloc_cpumasks(cs, NULL)) {
2517 return ERR_PTR(-ENOMEM);
2520 set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
2521 nodes_clear(cs->mems_allowed);
2522 nodes_clear(cs->effective_mems);
2523 fmeter_init(&cs->fmeter);
2524 cs->relax_domain_level = -1;
2529 static int cpuset_css_online(struct cgroup_subsys_state *css)
2531 struct cpuset *cs = css_cs(css);
2532 struct cpuset *parent = parent_cs(cs);
2533 struct cpuset *tmp_cs;
2534 struct cgroup_subsys_state *pos_css;
2539 mutex_lock(&cpuset_mutex);
2541 set_bit(CS_ONLINE, &cs->flags);
2542 if (is_spread_page(parent))
2543 set_bit(CS_SPREAD_PAGE, &cs->flags);
2544 if (is_spread_slab(parent))
2545 set_bit(CS_SPREAD_SLAB, &cs->flags);
2549 spin_lock_irq(&callback_lock);
2550 if (is_in_v2_mode()) {
2551 cpumask_copy(cs->effective_cpus, parent->effective_cpus);
2552 cs->effective_mems = parent->effective_mems;
2554 spin_unlock_irq(&callback_lock);
2556 if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
2560 * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
2561 * set. This flag handling is implemented in cgroup core for
2562 * histrical reasons - the flag may be specified during mount.
2564 * Currently, if any sibling cpusets have exclusive cpus or mem, we
2565 * refuse to clone the configuration - thereby refusing the task to
2566 * be entered, and as a result refusing the sys_unshare() or
2567 * clone() which initiated it. If this becomes a problem for some
2568 * users who wish to allow that scenario, then this could be
2569 * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
2570 * (and likewise for mems) to the new cgroup.
2573 cpuset_for_each_child(tmp_cs, pos_css, parent) {
2574 if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
2581 spin_lock_irq(&callback_lock);
2582 cs->mems_allowed = parent->mems_allowed;
2583 cs->effective_mems = parent->mems_allowed;
2584 cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
2585 cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
2586 spin_unlock_irq(&callback_lock);
2588 mutex_unlock(&cpuset_mutex);
2593 * If the cpuset being removed has its flag 'sched_load_balance'
2594 * enabled, then simulate turning sched_load_balance off, which
2595 * will call rebuild_sched_domains_locked(). That is not needed
2596 * in the default hierarchy where only changes in partition
2597 * will cause repartitioning.
2599 * If the cpuset has the 'sched.partition' flag enabled, simulate
2600 * turning 'sched.partition" off.
2603 static void cpuset_css_offline(struct cgroup_subsys_state *css)
2605 struct cpuset *cs = css_cs(css);
2607 mutex_lock(&cpuset_mutex);
2609 if (is_partition_root(cs))
2610 update_prstate(cs, 0);
2612 if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
2613 is_sched_load_balance(cs))
2614 update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
2617 clear_bit(CS_ONLINE, &cs->flags);
2619 mutex_unlock(&cpuset_mutex);
2622 static void cpuset_css_free(struct cgroup_subsys_state *css)
2624 struct cpuset *cs = css_cs(css);
2629 static void cpuset_bind(struct cgroup_subsys_state *root_css)
2631 mutex_lock(&cpuset_mutex);
2632 spin_lock_irq(&callback_lock);
2634 if (is_in_v2_mode()) {
2635 cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
2636 top_cpuset.mems_allowed = node_possible_map;
2638 cpumask_copy(top_cpuset.cpus_allowed,
2639 top_cpuset.effective_cpus);
2640 top_cpuset.mems_allowed = top_cpuset.effective_mems;
2643 spin_unlock_irq(&callback_lock);
2644 mutex_unlock(&cpuset_mutex);
2648 * Make sure the new task conform to the current state of its parent,
2649 * which could have been changed by cpuset just after it inherits the
2650 * state from the parent and before it sits on the cgroup's task list.
2652 static void cpuset_fork(struct task_struct *task)
2654 if (task_css_is_root(task, cpuset_cgrp_id))
2657 set_cpus_allowed_ptr(task, ¤t->cpus_allowed);
2658 task->mems_allowed = current->mems_allowed;
2661 struct cgroup_subsys cpuset_cgrp_subsys = {
2662 .css_alloc = cpuset_css_alloc,
2663 .css_online = cpuset_css_online,
2664 .css_offline = cpuset_css_offline,
2665 .css_free = cpuset_css_free,
2666 .can_attach = cpuset_can_attach,
2667 .cancel_attach = cpuset_cancel_attach,
2668 .attach = cpuset_attach,
2669 .post_attach = cpuset_post_attach,
2670 .bind = cpuset_bind,
2671 .fork = cpuset_fork,
2672 .legacy_cftypes = legacy_files,
2673 .dfl_cftypes = dfl_files,
2679 * cpuset_init - initialize cpusets at system boot
2681 * Description: Initialize top_cpuset and the cpuset internal file system,
2684 int __init cpuset_init(void)
2688 BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
2689 BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
2690 BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
2692 cpumask_setall(top_cpuset.cpus_allowed);
2693 nodes_setall(top_cpuset.mems_allowed);
2694 cpumask_setall(top_cpuset.effective_cpus);
2695 nodes_setall(top_cpuset.effective_mems);
2697 fmeter_init(&top_cpuset.fmeter);
2698 set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
2699 top_cpuset.relax_domain_level = -1;
2701 err = register_filesystem(&cpuset_fs_type);
2705 BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
2711 * If CPU and/or memory hotplug handlers, below, unplug any CPUs
2712 * or memory nodes, we need to walk over the cpuset hierarchy,
2713 * removing that CPU or node from all cpusets. If this removes the
2714 * last CPU or node from a cpuset, then move the tasks in the empty
2715 * cpuset to its next-highest non-empty parent.
2717 static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
2719 struct cpuset *parent;
2722 * Find its next-highest non-empty parent, (top cpuset
2723 * has online cpus, so can't be empty).
2725 parent = parent_cs(cs);
2726 while (cpumask_empty(parent->cpus_allowed) ||
2727 nodes_empty(parent->mems_allowed))
2728 parent = parent_cs(parent);
2730 if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
2731 pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
2732 pr_cont_cgroup_name(cs->css.cgroup);
2738 hotplug_update_tasks_legacy(struct cpuset *cs,
2739 struct cpumask *new_cpus, nodemask_t *new_mems,
2740 bool cpus_updated, bool mems_updated)
2744 spin_lock_irq(&callback_lock);
2745 cpumask_copy(cs->cpus_allowed, new_cpus);
2746 cpumask_copy(cs->effective_cpus, new_cpus);
2747 cs->mems_allowed = *new_mems;
2748 cs->effective_mems = *new_mems;
2749 spin_unlock_irq(&callback_lock);
2752 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
2753 * as the tasks will be migratecd to an ancestor.
2755 if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
2756 update_tasks_cpumask(cs);
2757 if (mems_updated && !nodes_empty(cs->mems_allowed))
2758 update_tasks_nodemask(cs);
2760 is_empty = cpumask_empty(cs->cpus_allowed) ||
2761 nodes_empty(cs->mems_allowed);
2763 mutex_unlock(&cpuset_mutex);
2766 * Move tasks to the nearest ancestor with execution resources,
2767 * This is full cgroup operation which will also call back into
2768 * cpuset. Should be done outside any lock.
2771 remove_tasks_in_empty_cpuset(cs);
2773 mutex_lock(&cpuset_mutex);
2777 hotplug_update_tasks(struct cpuset *cs,
2778 struct cpumask *new_cpus, nodemask_t *new_mems,
2779 bool cpus_updated, bool mems_updated)
2781 if (cpumask_empty(new_cpus))
2782 cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
2783 if (nodes_empty(*new_mems))
2784 *new_mems = parent_cs(cs)->effective_mems;
2786 spin_lock_irq(&callback_lock);
2787 cpumask_copy(cs->effective_cpus, new_cpus);
2788 cs->effective_mems = *new_mems;
2789 spin_unlock_irq(&callback_lock);
2792 update_tasks_cpumask(cs);
2794 update_tasks_nodemask(cs);
2798 * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
2799 * @cs: cpuset in interest
2801 * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
2802 * offline, update @cs accordingly. If @cs ends up with no CPU or memory,
2803 * all its tasks are moved to the nearest ancestor with both resources.
2805 static void cpuset_hotplug_update_tasks(struct cpuset *cs)
2807 static cpumask_t new_cpus;
2808 static nodemask_t new_mems;
2812 wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
2814 mutex_lock(&cpuset_mutex);
2817 * We have raced with task attaching. We wait until attaching
2818 * is finished, so we won't attach a task to an empty cpuset.
2820 if (cs->attach_in_progress) {
2821 mutex_unlock(&cpuset_mutex);
2825 cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus);
2826 nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems);
2828 cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
2829 mems_updated = !nodes_equal(new_mems, cs->effective_mems);
2831 if (is_in_v2_mode())
2832 hotplug_update_tasks(cs, &new_cpus, &new_mems,
2833 cpus_updated, mems_updated);
2835 hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
2836 cpus_updated, mems_updated);
2838 mutex_unlock(&cpuset_mutex);
2841 static bool force_rebuild;
2843 void cpuset_force_rebuild(void)
2845 force_rebuild = true;
2849 * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
2851 * This function is called after either CPU or memory configuration has
2852 * changed and updates cpuset accordingly. The top_cpuset is always
2853 * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
2854 * order to make cpusets transparent (of no affect) on systems that are
2855 * actively using CPU hotplug but making no active use of cpusets.
2857 * Non-root cpusets are only affected by offlining. If any CPUs or memory
2858 * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
2861 * Note that CPU offlining during suspend is ignored. We don't modify
2862 * cpusets across suspend/resume cycles at all.
2864 static void cpuset_hotplug_workfn(struct work_struct *work)
2866 static cpumask_t new_cpus;
2867 static nodemask_t new_mems;
2868 bool cpus_updated, mems_updated;
2869 bool on_dfl = is_in_v2_mode();
2871 mutex_lock(&cpuset_mutex);
2873 /* fetch the available cpus/mems and find out which changed how */
2874 cpumask_copy(&new_cpus, cpu_active_mask);
2875 new_mems = node_states[N_MEMORY];
2877 cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
2878 mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
2880 /* synchronize cpus_allowed to cpu_active_mask */
2882 spin_lock_irq(&callback_lock);
2884 cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
2885 cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
2886 spin_unlock_irq(&callback_lock);
2887 /* we don't mess with cpumasks of tasks in top_cpuset */
2890 /* synchronize mems_allowed to N_MEMORY */
2892 spin_lock_irq(&callback_lock);
2894 top_cpuset.mems_allowed = new_mems;
2895 top_cpuset.effective_mems = new_mems;
2896 spin_unlock_irq(&callback_lock);
2897 update_tasks_nodemask(&top_cpuset);
2900 mutex_unlock(&cpuset_mutex);
2902 /* if cpus or mems changed, we need to propagate to descendants */
2903 if (cpus_updated || mems_updated) {
2905 struct cgroup_subsys_state *pos_css;
2908 cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
2909 if (cs == &top_cpuset || !css_tryget_online(&cs->css))
2913 cpuset_hotplug_update_tasks(cs);
2921 /* rebuild sched domains if cpus_allowed has changed */
2922 if (cpus_updated || force_rebuild) {
2923 force_rebuild = false;
2924 rebuild_sched_domains();
2928 void cpuset_update_active_cpus(void)
2931 * We're inside cpu hotplug critical region which usually nests
2932 * inside cgroup synchronization. Bounce actual hotplug processing
2933 * to a work item to avoid reverse locking order.
2935 schedule_work(&cpuset_hotplug_work);
2938 void cpuset_wait_for_hotplug(void)
2940 flush_work(&cpuset_hotplug_work);
2944 * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
2945 * Call this routine anytime after node_states[N_MEMORY] changes.
2946 * See cpuset_update_active_cpus() for CPU hotplug handling.
2948 static int cpuset_track_online_nodes(struct notifier_block *self,
2949 unsigned long action, void *arg)
2951 schedule_work(&cpuset_hotplug_work);
2955 static struct notifier_block cpuset_track_online_nodes_nb = {
2956 .notifier_call = cpuset_track_online_nodes,
2957 .priority = 10, /* ??! */
2961 * cpuset_init_smp - initialize cpus_allowed
2963 * Description: Finish top cpuset after cpu, node maps are initialized
2965 void __init cpuset_init_smp(void)
2967 cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
2968 top_cpuset.mems_allowed = node_states[N_MEMORY];
2969 top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
2971 cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
2972 top_cpuset.effective_mems = node_states[N_MEMORY];
2974 register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
2976 cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
2977 BUG_ON(!cpuset_migrate_mm_wq);
2981 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
2982 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
2983 * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
2985 * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
2986 * attached to the specified @tsk. Guaranteed to return some non-empty
2987 * subset of cpu_online_mask, even if this means going outside the
2991 void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
2993 unsigned long flags;
2995 spin_lock_irqsave(&callback_lock, flags);
2997 guarantee_online_cpus(task_cs(tsk), pmask);
2999 spin_unlock_irqrestore(&callback_lock, flags);
3002 void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
3005 do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
3009 * We own tsk->cpus_allowed, nobody can change it under us.
3011 * But we used cs && cs->cpus_allowed lockless and thus can
3012 * race with cgroup_attach_task() or update_cpumask() and get
3013 * the wrong tsk->cpus_allowed. However, both cases imply the
3014 * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
3015 * which takes task_rq_lock().
3017 * If we are called after it dropped the lock we must see all
3018 * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
3019 * set any mask even if it is not right from task_cs() pov,
3020 * the pending set_cpus_allowed_ptr() will fix things.
3022 * select_fallback_rq() will fix things ups and set cpu_possible_mask
3027 void __init cpuset_init_current_mems_allowed(void)
3029 nodes_setall(current->mems_allowed);
3033 * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
3034 * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
3036 * Description: Returns the nodemask_t mems_allowed of the cpuset
3037 * attached to the specified @tsk. Guaranteed to return some non-empty
3038 * subset of node_states[N_MEMORY], even if this means going outside the
3042 nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
3045 unsigned long flags;
3047 spin_lock_irqsave(&callback_lock, flags);
3049 guarantee_online_mems(task_cs(tsk), &mask);
3051 spin_unlock_irqrestore(&callback_lock, flags);
3057 * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
3058 * @nodemask: the nodemask to be checked
3060 * Are any of the nodes in the nodemask allowed in current->mems_allowed?
3062 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
3064 return nodes_intersects(*nodemask, current->mems_allowed);
3068 * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
3069 * mem_hardwall ancestor to the specified cpuset. Call holding
3070 * callback_lock. If no ancestor is mem_exclusive or mem_hardwall
3071 * (an unusual configuration), then returns the root cpuset.
3073 static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
3075 while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
3081 * cpuset_node_allowed - Can we allocate on a memory node?
3082 * @node: is this an allowed node?
3083 * @gfp_mask: memory allocation flags
3085 * If we're in interrupt, yes, we can always allocate. If @node is set in
3086 * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this
3087 * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
3088 * yes. If current has access to memory reserves as an oom victim, yes.
3091 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
3092 * and do not allow allocations outside the current tasks cpuset
3093 * unless the task has been OOM killed.
3094 * GFP_KERNEL allocations are not so marked, so can escape to the
3095 * nearest enclosing hardwalled ancestor cpuset.
3097 * Scanning up parent cpusets requires callback_lock. The
3098 * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
3099 * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
3100 * current tasks mems_allowed came up empty on the first pass over
3101 * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
3102 * cpuset are short of memory, might require taking the callback_lock.
3104 * The first call here from mm/page_alloc:get_page_from_freelist()
3105 * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
3106 * so no allocation on a node outside the cpuset is allowed (unless
3107 * in interrupt, of course).
3109 * The second pass through get_page_from_freelist() doesn't even call
3110 * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
3111 * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
3112 * in alloc_flags. That logic and the checks below have the combined
3114 * in_interrupt - any node ok (current task context irrelevant)
3115 * GFP_ATOMIC - any node ok
3116 * tsk_is_oom_victim - any node ok
3117 * GFP_KERNEL - any node in enclosing hardwalled cpuset ok
3118 * GFP_USER - only nodes in current tasks mems allowed ok.
3120 bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
3122 struct cpuset *cs; /* current cpuset ancestors */
3123 int allowed; /* is allocation in zone z allowed? */
3124 unsigned long flags;
3128 if (node_isset(node, current->mems_allowed))
3131 * Allow tasks that have access to memory reserves because they have
3132 * been OOM killed to get memory anywhere.
3134 if (unlikely(tsk_is_oom_victim(current)))
3136 if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
3139 if (current->flags & PF_EXITING) /* Let dying task have memory */
3142 /* Not hardwall and node outside mems_allowed: scan up cpusets */
3143 spin_lock_irqsave(&callback_lock, flags);
3146 cs = nearest_hardwall_ancestor(task_cs(current));
3147 allowed = node_isset(node, cs->mems_allowed);
3150 spin_unlock_irqrestore(&callback_lock, flags);
3155 * cpuset_mem_spread_node() - On which node to begin search for a file page
3156 * cpuset_slab_spread_node() - On which node to begin search for a slab page
3158 * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
3159 * tasks in a cpuset with is_spread_page or is_spread_slab set),
3160 * and if the memory allocation used cpuset_mem_spread_node()
3161 * to determine on which node to start looking, as it will for
3162 * certain page cache or slab cache pages such as used for file
3163 * system buffers and inode caches, then instead of starting on the
3164 * local node to look for a free page, rather spread the starting
3165 * node around the tasks mems_allowed nodes.
3167 * We don't have to worry about the returned node being offline
3168 * because "it can't happen", and even if it did, it would be ok.
3170 * The routines calling guarantee_online_mems() are careful to
3171 * only set nodes in task->mems_allowed that are online. So it
3172 * should not be possible for the following code to return an
3173 * offline node. But if it did, that would be ok, as this routine
3174 * is not returning the node where the allocation must be, only
3175 * the node where the search should start. The zonelist passed to
3176 * __alloc_pages() will include all nodes. If the slab allocator
3177 * is passed an offline node, it will fall back to the local node.
3178 * See kmem_cache_alloc_node().
3181 static int cpuset_spread_node(int *rotor)
3183 return *rotor = next_node_in(*rotor, current->mems_allowed);
3186 int cpuset_mem_spread_node(void)
3188 if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
3189 current->cpuset_mem_spread_rotor =
3190 node_random(¤t->mems_allowed);
3192 return cpuset_spread_node(¤t->cpuset_mem_spread_rotor);
3195 int cpuset_slab_spread_node(void)
3197 if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
3198 current->cpuset_slab_spread_rotor =
3199 node_random(¤t->mems_allowed);
3201 return cpuset_spread_node(¤t->cpuset_slab_spread_rotor);
3204 EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
3207 * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
3208 * @tsk1: pointer to task_struct of some task.
3209 * @tsk2: pointer to task_struct of some other task.
3211 * Description: Return true if @tsk1's mems_allowed intersects the
3212 * mems_allowed of @tsk2. Used by the OOM killer to determine if
3213 * one of the task's memory usage might impact the memory available
3217 int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
3218 const struct task_struct *tsk2)
3220 return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
3224 * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
3226 * Description: Prints current's name, cpuset name, and cached copy of its
3227 * mems_allowed to the kernel log.
3229 void cpuset_print_current_mems_allowed(void)
3231 struct cgroup *cgrp;
3235 cgrp = task_cs(current)->css.cgroup;
3236 pr_info("%s cpuset=", current->comm);
3237 pr_cont_cgroup_name(cgrp);
3238 pr_cont(" mems_allowed=%*pbl\n",
3239 nodemask_pr_args(¤t->mems_allowed));
3245 * Collection of memory_pressure is suppressed unless
3246 * this flag is enabled by writing "1" to the special
3247 * cpuset file 'memory_pressure_enabled' in the root cpuset.
3250 int cpuset_memory_pressure_enabled __read_mostly;
3253 * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
3255 * Keep a running average of the rate of synchronous (direct)
3256 * page reclaim efforts initiated by tasks in each cpuset.
3258 * This represents the rate at which some task in the cpuset
3259 * ran low on memory on all nodes it was allowed to use, and
3260 * had to enter the kernels page reclaim code in an effort to
3261 * create more free memory by tossing clean pages or swapping
3262 * or writing dirty pages.
3264 * Display to user space in the per-cpuset read-only file
3265 * "memory_pressure". Value displayed is an integer
3266 * representing the recent rate of entry into the synchronous
3267 * (direct) page reclaim by any task attached to the cpuset.
3270 void __cpuset_memory_pressure_bump(void)
3273 fmeter_markevent(&task_cs(current)->fmeter);
3277 #ifdef CONFIG_PROC_PID_CPUSET
3279 * proc_cpuset_show()
3280 * - Print tasks cpuset path into seq_file.
3281 * - Used for /proc/<pid>/cpuset.
3282 * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
3283 * doesn't really matter if tsk->cpuset changes after we read it,
3284 * and we take cpuset_mutex, keeping cpuset_attach() from changing it
3287 int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
3288 struct pid *pid, struct task_struct *tsk)
3291 struct cgroup_subsys_state *css;
3295 buf = kmalloc(PATH_MAX, GFP_KERNEL);
3299 css = task_get_css(tsk, cpuset_cgrp_id);
3300 retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
3301 current->nsproxy->cgroup_ns);
3303 if (retval >= PATH_MAX)
3304 retval = -ENAMETOOLONG;
3315 #endif /* CONFIG_PROC_PID_CPUSET */
3317 /* Display task mems_allowed in /proc/<pid>/status file. */
3318 void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
3320 seq_printf(m, "Mems_allowed:\t%*pb\n",
3321 nodemask_pr_args(&task->mems_allowed));
3322 seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
3323 nodemask_pr_args(&task->mems_allowed));