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/fs_context.h>
43 #include <linux/namei.h>
44 #include <linux/pagemap.h>
45 #include <linux/proc_fs.h>
46 #include <linux/rcupdate.h>
47 #include <linux/sched.h>
48 #include <linux/sched/deadline.h>
49 #include <linux/sched/mm.h>
50 #include <linux/sched/task.h>
51 #include <linux/seq_file.h>
52 #include <linux/security.h>
53 #include <linux/slab.h>
54 #include <linux/spinlock.h>
55 #include <linux/stat.h>
56 #include <linux/string.h>
57 #include <linux/time.h>
58 #include <linux/time64.h>
59 #include <linux/backing-dev.h>
60 #include <linux/sort.h>
61 #include <linux/oom.h>
62 #include <linux/sched/isolation.h>
63 #include <linux/uaccess.h>
64 #include <linux/atomic.h>
65 #include <linux/mutex.h>
66 #include <linux/cgroup.h>
67 #include <linux/wait.h>
69 DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key
);
70 DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key
);
72 /* See "Frequency meter" comments, below. */
75 int cnt
; /* unprocessed events count */
76 int val
; /* most recent output value */
77 time64_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 */
87 * On default hierarchy:
89 * The user-configured masks can only be changed by writing to
90 * cpuset.cpus and cpuset.mems, and won't be limited by the
93 * The effective masks is the real masks that apply to the tasks
94 * in the cpuset. They may be changed if the configured masks are
95 * changed or hotplug happens.
97 * effective_mask == configured_mask & parent's effective_mask,
98 * and if it ends up empty, it will inherit the parent's mask.
101 * On legacy hierarchy:
103 * The user-configured masks are always the same with effective masks.
106 /* user-configured CPUs and Memory Nodes allow to tasks */
107 cpumask_var_t cpus_allowed
;
108 nodemask_t mems_allowed
;
110 /* effective CPUs and Memory Nodes allow to tasks */
111 cpumask_var_t effective_cpus
;
112 nodemask_t effective_mems
;
115 * CPUs allocated to child sub-partitions (default hierarchy only)
116 * - CPUs granted by the parent = effective_cpus U subparts_cpus
117 * - effective_cpus and subparts_cpus are mutually exclusive.
119 * effective_cpus contains only onlined CPUs, but subparts_cpus
120 * may have offlined ones.
122 cpumask_var_t subparts_cpus
;
125 * This is old Memory Nodes tasks took on.
127 * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
128 * - A new cpuset's old_mems_allowed is initialized when some
129 * task is moved into it.
130 * - old_mems_allowed is used in cpuset_migrate_mm() when we change
131 * cpuset.mems_allowed and have tasks' nodemask updated, and
132 * then old_mems_allowed is updated to mems_allowed.
134 nodemask_t old_mems_allowed
;
136 struct fmeter fmeter
; /* memory_pressure filter */
139 * Tasks are being attached to this cpuset. Used to prevent
140 * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
142 int attach_in_progress
;
144 /* partition number for rebuild_sched_domains() */
147 /* for custom sched domain */
148 int relax_domain_level
;
150 /* number of CPUs in subparts_cpus */
151 int nr_subparts_cpus
;
153 /* partition root state */
154 int partition_root_state
;
157 * Default hierarchy only:
158 * use_parent_ecpus - set if using parent's effective_cpus
159 * child_ecpus_count - # of children with use_parent_ecpus set
161 int use_parent_ecpus
;
162 int child_ecpus_count
;
164 /* Handle for cpuset.cpus.partition */
165 struct cgroup_file partition_file
;
169 * Partition root states:
171 * 0 - not a partition root
175 * -1 - invalid partition root
176 * None of the cpus in cpus_allowed can be put into the parent's
177 * subparts_cpus. In this case, the cpuset is not a real partition
178 * root anymore. However, the CPU_EXCLUSIVE bit will still be set
179 * and the cpuset can be restored back to a partition root if the
180 * parent cpuset can give more CPUs back to this child cpuset.
182 #define PRS_DISABLED 0
183 #define PRS_ENABLED 1
187 * Temporary cpumasks for working with partitions that are passed among
188 * functions to avoid memory allocation in inner functions.
191 cpumask_var_t addmask
, delmask
; /* For partition root */
192 cpumask_var_t new_cpus
; /* For update_cpumasks_hier() */
195 static inline struct cpuset
*css_cs(struct cgroup_subsys_state
*css
)
197 return css
? container_of(css
, struct cpuset
, css
) : NULL
;
200 /* Retrieve the cpuset for a task */
201 static inline struct cpuset
*task_cs(struct task_struct
*task
)
203 return css_cs(task_css(task
, cpuset_cgrp_id
));
206 static inline struct cpuset
*parent_cs(struct cpuset
*cs
)
208 return css_cs(cs
->css
.parent
);
211 /* bits in struct cpuset flags field */
218 CS_SCHED_LOAD_BALANCE
,
223 /* convenient tests for these bits */
224 static inline bool is_cpuset_online(struct cpuset
*cs
)
226 return test_bit(CS_ONLINE
, &cs
->flags
) && !css_is_dying(&cs
->css
);
229 static inline int is_cpu_exclusive(const struct cpuset
*cs
)
231 return test_bit(CS_CPU_EXCLUSIVE
, &cs
->flags
);
234 static inline int is_mem_exclusive(const struct cpuset
*cs
)
236 return test_bit(CS_MEM_EXCLUSIVE
, &cs
->flags
);
239 static inline int is_mem_hardwall(const struct cpuset
*cs
)
241 return test_bit(CS_MEM_HARDWALL
, &cs
->flags
);
244 static inline int is_sched_load_balance(const struct cpuset
*cs
)
246 return test_bit(CS_SCHED_LOAD_BALANCE
, &cs
->flags
);
249 static inline int is_memory_migrate(const struct cpuset
*cs
)
251 return test_bit(CS_MEMORY_MIGRATE
, &cs
->flags
);
254 static inline int is_spread_page(const struct cpuset
*cs
)
256 return test_bit(CS_SPREAD_PAGE
, &cs
->flags
);
259 static inline int is_spread_slab(const struct cpuset
*cs
)
261 return test_bit(CS_SPREAD_SLAB
, &cs
->flags
);
264 static inline int is_partition_root(const struct cpuset
*cs
)
266 return cs
->partition_root_state
> 0;
270 * Send notification event of whenever partition_root_state changes.
272 static inline void notify_partition_change(struct cpuset
*cs
,
273 int old_prs
, int new_prs
)
275 if (old_prs
!= new_prs
)
276 cgroup_file_notify(&cs
->partition_file
);
279 static struct cpuset top_cpuset
= {
280 .flags
= ((1 << CS_ONLINE
) | (1 << CS_CPU_EXCLUSIVE
) |
281 (1 << CS_MEM_EXCLUSIVE
)),
282 .partition_root_state
= PRS_ENABLED
,
286 * cpuset_for_each_child - traverse online children of a cpuset
287 * @child_cs: loop cursor pointing to the current child
288 * @pos_css: used for iteration
289 * @parent_cs: target cpuset to walk children of
291 * Walk @child_cs through the online children of @parent_cs. Must be used
292 * with RCU read locked.
294 #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
295 css_for_each_child((pos_css), &(parent_cs)->css) \
296 if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
299 * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
300 * @des_cs: loop cursor pointing to the current descendant
301 * @pos_css: used for iteration
302 * @root_cs: target cpuset to walk ancestor of
304 * Walk @des_cs through the online descendants of @root_cs. Must be used
305 * with RCU read locked. The caller may modify @pos_css by calling
306 * css_rightmost_descendant() to skip subtree. @root_cs is included in the
307 * iteration and the first node to be visited.
309 #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
310 css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
311 if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
314 * There are two global locks guarding cpuset structures - cpuset_rwsem and
315 * callback_lock. We also require taking task_lock() when dereferencing a
316 * task's cpuset pointer. See "The task_lock() exception", at the end of this
317 * comment. The cpuset code uses only cpuset_rwsem write lock. Other
318 * kernel subsystems can use cpuset_read_lock()/cpuset_read_unlock() to
319 * prevent change to cpuset structures.
321 * A task must hold both locks to modify cpusets. If a task holds
322 * cpuset_rwsem, it blocks others wanting that rwsem, ensuring that it
323 * is the only task able to also acquire callback_lock and be able to
324 * modify cpusets. It can perform various checks on the cpuset structure
325 * first, knowing nothing will change. It can also allocate memory while
326 * just holding cpuset_rwsem. While it is performing these checks, various
327 * callback routines can briefly acquire callback_lock to query cpusets.
328 * Once it is ready to make the changes, it takes callback_lock, blocking
331 * Calls to the kernel memory allocator can not be made while holding
332 * callback_lock, as that would risk double tripping on callback_lock
333 * from one of the callbacks into the cpuset code from within
336 * If a task is only holding callback_lock, then it has read-only
339 * Now, the task_struct fields mems_allowed and mempolicy may be changed
340 * by other task, we use alloc_lock in the task_struct fields to protect
343 * The cpuset_common_file_read() handlers only hold callback_lock across
344 * small pieces of code, such as when reading out possibly multi-word
345 * cpumasks and nodemasks.
347 * Accessing a task's cpuset should be done in accordance with the
348 * guidelines for accessing subsystem state in kernel/cgroup.c
351 DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem
);
353 void cpuset_read_lock(void)
355 percpu_down_read(&cpuset_rwsem
);
358 void cpuset_read_unlock(void)
360 percpu_up_read(&cpuset_rwsem
);
363 static DEFINE_SPINLOCK(callback_lock
);
365 static struct workqueue_struct
*cpuset_migrate_mm_wq
;
368 * CPU / memory hotplug is handled asynchronously.
370 static void cpuset_hotplug_workfn(struct work_struct
*work
);
371 static DECLARE_WORK(cpuset_hotplug_work
, cpuset_hotplug_workfn
);
373 static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq
);
376 * Cgroup v2 behavior is used on the "cpus" and "mems" control files when
377 * on default hierarchy or when the cpuset_v2_mode flag is set by mounting
378 * the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option.
379 * With v2 behavior, "cpus" and "mems" are always what the users have
380 * requested and won't be changed by hotplug events. Only the effective
381 * cpus or mems will be affected.
383 static inline bool is_in_v2_mode(void)
385 return cgroup_subsys_on_dfl(cpuset_cgrp_subsys
) ||
386 (cpuset_cgrp_subsys
.root
->flags
& CGRP_ROOT_CPUSET_V2_MODE
);
390 * Return in pmask the portion of a task's cpusets's cpus_allowed that
391 * are online and are capable of running the task. If none are found,
392 * walk up the cpuset hierarchy until we find one that does have some
395 * One way or another, we guarantee to return some non-empty subset
396 * of cpu_online_mask.
398 * Call with callback_lock or cpuset_rwsem held.
400 static void guarantee_online_cpus(struct task_struct
*tsk
,
401 struct cpumask
*pmask
)
403 const struct cpumask
*possible_mask
= task_cpu_possible_mask(tsk
);
406 if (WARN_ON(!cpumask_and(pmask
, possible_mask
, cpu_online_mask
)))
407 cpumask_copy(pmask
, cpu_online_mask
);
412 while (!cpumask_intersects(cs
->effective_cpus
, pmask
)) {
416 * The top cpuset doesn't have any online cpu as a
417 * consequence of a race between cpuset_hotplug_work
418 * and cpu hotplug notifier. But we know the top
419 * cpuset's effective_cpus is on its way to be
420 * identical to cpu_online_mask.
425 cpumask_and(pmask
, pmask
, cs
->effective_cpus
);
432 * Return in *pmask the portion of a cpusets's mems_allowed that
433 * are online, with memory. If none are online with memory, walk
434 * up the cpuset hierarchy until we find one that does have some
435 * online mems. The top cpuset always has some mems online.
437 * One way or another, we guarantee to return some non-empty subset
438 * of node_states[N_MEMORY].
440 * Call with callback_lock or cpuset_rwsem held.
442 static void guarantee_online_mems(struct cpuset
*cs
, nodemask_t
*pmask
)
444 while (!nodes_intersects(cs
->effective_mems
, node_states
[N_MEMORY
]))
446 nodes_and(*pmask
, cs
->effective_mems
, node_states
[N_MEMORY
]);
450 * update task's spread flag if cpuset's page/slab spread flag is set
452 * Call with callback_lock or cpuset_rwsem held.
454 static void cpuset_update_task_spread_flag(struct cpuset
*cs
,
455 struct task_struct
*tsk
)
457 if (is_spread_page(cs
))
458 task_set_spread_page(tsk
);
460 task_clear_spread_page(tsk
);
462 if (is_spread_slab(cs
))
463 task_set_spread_slab(tsk
);
465 task_clear_spread_slab(tsk
);
469 * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
471 * One cpuset is a subset of another if all its allowed CPUs and
472 * Memory Nodes are a subset of the other, and its exclusive flags
473 * are only set if the other's are set. Call holding cpuset_rwsem.
476 static int is_cpuset_subset(const struct cpuset
*p
, const struct cpuset
*q
)
478 return cpumask_subset(p
->cpus_allowed
, q
->cpus_allowed
) &&
479 nodes_subset(p
->mems_allowed
, q
->mems_allowed
) &&
480 is_cpu_exclusive(p
) <= is_cpu_exclusive(q
) &&
481 is_mem_exclusive(p
) <= is_mem_exclusive(q
);
485 * alloc_cpumasks - allocate three cpumasks for cpuset
486 * @cs: the cpuset that have cpumasks to be allocated.
487 * @tmp: the tmpmasks structure pointer
488 * Return: 0 if successful, -ENOMEM otherwise.
490 * Only one of the two input arguments should be non-NULL.
492 static inline int alloc_cpumasks(struct cpuset
*cs
, struct tmpmasks
*tmp
)
494 cpumask_var_t
*pmask1
, *pmask2
, *pmask3
;
497 pmask1
= &cs
->cpus_allowed
;
498 pmask2
= &cs
->effective_cpus
;
499 pmask3
= &cs
->subparts_cpus
;
501 pmask1
= &tmp
->new_cpus
;
502 pmask2
= &tmp
->addmask
;
503 pmask3
= &tmp
->delmask
;
506 if (!zalloc_cpumask_var(pmask1
, GFP_KERNEL
))
509 if (!zalloc_cpumask_var(pmask2
, GFP_KERNEL
))
512 if (!zalloc_cpumask_var(pmask3
, GFP_KERNEL
))
518 free_cpumask_var(*pmask2
);
520 free_cpumask_var(*pmask1
);
525 * free_cpumasks - free cpumasks in a tmpmasks structure
526 * @cs: the cpuset that have cpumasks to be free.
527 * @tmp: the tmpmasks structure pointer
529 static inline void free_cpumasks(struct cpuset
*cs
, struct tmpmasks
*tmp
)
532 free_cpumask_var(cs
->cpus_allowed
);
533 free_cpumask_var(cs
->effective_cpus
);
534 free_cpumask_var(cs
->subparts_cpus
);
537 free_cpumask_var(tmp
->new_cpus
);
538 free_cpumask_var(tmp
->addmask
);
539 free_cpumask_var(tmp
->delmask
);
544 * alloc_trial_cpuset - allocate a trial cpuset
545 * @cs: the cpuset that the trial cpuset duplicates
547 static struct cpuset
*alloc_trial_cpuset(struct cpuset
*cs
)
549 struct cpuset
*trial
;
551 trial
= kmemdup(cs
, sizeof(*cs
), GFP_KERNEL
);
555 if (alloc_cpumasks(trial
, NULL
)) {
560 cpumask_copy(trial
->cpus_allowed
, cs
->cpus_allowed
);
561 cpumask_copy(trial
->effective_cpus
, cs
->effective_cpus
);
566 * free_cpuset - free the cpuset
567 * @cs: the cpuset to be freed
569 static inline void free_cpuset(struct cpuset
*cs
)
571 free_cpumasks(cs
, NULL
);
576 * validate_change() - Used to validate that any proposed cpuset change
577 * follows the structural rules for cpusets.
579 * If we replaced the flag and mask values of the current cpuset
580 * (cur) with those values in the trial cpuset (trial), would
581 * our various subset and exclusive rules still be valid? Presumes
584 * 'cur' is the address of an actual, in-use cpuset. Operations
585 * such as list traversal that depend on the actual address of the
586 * cpuset in the list must use cur below, not trial.
588 * 'trial' is the address of bulk structure copy of cur, with
589 * perhaps one or more of the fields cpus_allowed, mems_allowed,
590 * or flags changed to new, trial values.
592 * Return 0 if valid, -errno if not.
595 static int validate_change(struct cpuset
*cur
, struct cpuset
*trial
)
597 struct cgroup_subsys_state
*css
;
598 struct cpuset
*c
, *par
;
603 /* Each of our child cpusets must be a subset of us */
605 cpuset_for_each_child(c
, css
, cur
)
606 if (!is_cpuset_subset(c
, trial
))
609 /* Remaining checks don't apply to root cpuset */
611 if (cur
== &top_cpuset
)
614 par
= parent_cs(cur
);
616 /* On legacy hierarchy, we must be a subset of our parent cpuset. */
618 if (!is_in_v2_mode() && !is_cpuset_subset(trial
, par
))
622 * If either I or some sibling (!= me) is exclusive, we can't
626 cpuset_for_each_child(c
, css
, par
) {
627 if ((is_cpu_exclusive(trial
) || is_cpu_exclusive(c
)) &&
629 cpumask_intersects(trial
->cpus_allowed
, c
->cpus_allowed
))
631 if ((is_mem_exclusive(trial
) || is_mem_exclusive(c
)) &&
633 nodes_intersects(trial
->mems_allowed
, c
->mems_allowed
))
638 * Cpusets with tasks - existing or newly being attached - can't
639 * be changed to have empty cpus_allowed or mems_allowed.
642 if ((cgroup_is_populated(cur
->css
.cgroup
) || cur
->attach_in_progress
)) {
643 if (!cpumask_empty(cur
->cpus_allowed
) &&
644 cpumask_empty(trial
->cpus_allowed
))
646 if (!nodes_empty(cur
->mems_allowed
) &&
647 nodes_empty(trial
->mems_allowed
))
652 * We can't shrink if we won't have enough room for SCHED_DEADLINE
656 if (is_cpu_exclusive(cur
) &&
657 !cpuset_cpumask_can_shrink(cur
->cpus_allowed
,
658 trial
->cpus_allowed
))
669 * Helper routine for generate_sched_domains().
670 * Do cpusets a, b have overlapping effective cpus_allowed masks?
672 static int cpusets_overlap(struct cpuset
*a
, struct cpuset
*b
)
674 return cpumask_intersects(a
->effective_cpus
, b
->effective_cpus
);
678 update_domain_attr(struct sched_domain_attr
*dattr
, struct cpuset
*c
)
680 if (dattr
->relax_domain_level
< c
->relax_domain_level
)
681 dattr
->relax_domain_level
= c
->relax_domain_level
;
685 static void update_domain_attr_tree(struct sched_domain_attr
*dattr
,
686 struct cpuset
*root_cs
)
689 struct cgroup_subsys_state
*pos_css
;
692 cpuset_for_each_descendant_pre(cp
, pos_css
, root_cs
) {
693 /* skip the whole subtree if @cp doesn't have any CPU */
694 if (cpumask_empty(cp
->cpus_allowed
)) {
695 pos_css
= css_rightmost_descendant(pos_css
);
699 if (is_sched_load_balance(cp
))
700 update_domain_attr(dattr
, cp
);
705 /* Must be called with cpuset_rwsem held. */
706 static inline int nr_cpusets(void)
708 /* jump label reference count + the top-level cpuset */
709 return static_key_count(&cpusets_enabled_key
.key
) + 1;
713 * generate_sched_domains()
715 * This function builds a partial partition of the systems CPUs
716 * A 'partial partition' is a set of non-overlapping subsets whose
717 * union is a subset of that set.
718 * The output of this function needs to be passed to kernel/sched/core.c
719 * partition_sched_domains() routine, which will rebuild the scheduler's
720 * load balancing domains (sched domains) as specified by that partial
723 * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst
724 * for a background explanation of this.
726 * Does not return errors, on the theory that the callers of this
727 * routine would rather not worry about failures to rebuild sched
728 * domains when operating in the severe memory shortage situations
729 * that could cause allocation failures below.
731 * Must be called with cpuset_rwsem held.
733 * The three key local variables below are:
734 * cp - cpuset pointer, used (together with pos_css) to perform a
735 * top-down scan of all cpusets. For our purposes, rebuilding
736 * the schedulers sched domains, we can ignore !is_sched_load_
738 * csa - (for CpuSet Array) Array of pointers to all the cpusets
739 * that need to be load balanced, for convenient iterative
740 * access by the subsequent code that finds the best partition,
741 * i.e the set of domains (subsets) of CPUs such that the
742 * cpus_allowed of every cpuset marked is_sched_load_balance
743 * is a subset of one of these domains, while there are as
744 * many such domains as possible, each as small as possible.
745 * doms - Conversion of 'csa' to an array of cpumasks, for passing to
746 * the kernel/sched/core.c routine partition_sched_domains() in a
747 * convenient format, that can be easily compared to the prior
748 * value to determine what partition elements (sched domains)
749 * were changed (added or removed.)
751 * Finding the best partition (set of domains):
752 * The triple nested loops below over i, j, k scan over the
753 * load balanced cpusets (using the array of cpuset pointers in
754 * csa[]) looking for pairs of cpusets that have overlapping
755 * cpus_allowed, but which don't have the same 'pn' partition
756 * number and gives them in the same partition number. It keeps
757 * looping on the 'restart' label until it can no longer find
760 * The union of the cpus_allowed masks from the set of
761 * all cpusets having the same 'pn' value then form the one
762 * element of the partition (one sched domain) to be passed to
763 * partition_sched_domains().
765 static int generate_sched_domains(cpumask_var_t
**domains
,
766 struct sched_domain_attr
**attributes
)
768 struct cpuset
*cp
; /* top-down scan of cpusets */
769 struct cpuset
**csa
; /* array of all cpuset ptrs */
770 int csn
; /* how many cpuset ptrs in csa so far */
771 int i
, j
, k
; /* indices for partition finding loops */
772 cpumask_var_t
*doms
; /* resulting partition; i.e. sched domains */
773 struct sched_domain_attr
*dattr
; /* attributes for custom domains */
774 int ndoms
= 0; /* number of sched domains in result */
775 int nslot
; /* next empty doms[] struct cpumask slot */
776 struct cgroup_subsys_state
*pos_css
;
777 bool root_load_balance
= is_sched_load_balance(&top_cpuset
);
783 /* Special case for the 99% of systems with one, full, sched domain */
784 if (root_load_balance
&& !top_cpuset
.nr_subparts_cpus
) {
786 doms
= alloc_sched_domains(ndoms
);
790 dattr
= kmalloc(sizeof(struct sched_domain_attr
), GFP_KERNEL
);
792 *dattr
= SD_ATTR_INIT
;
793 update_domain_attr_tree(dattr
, &top_cpuset
);
795 cpumask_and(doms
[0], top_cpuset
.effective_cpus
,
796 housekeeping_cpumask(HK_FLAG_DOMAIN
));
801 csa
= kmalloc_array(nr_cpusets(), sizeof(cp
), GFP_KERNEL
);
807 if (root_load_balance
)
808 csa
[csn
++] = &top_cpuset
;
809 cpuset_for_each_descendant_pre(cp
, pos_css
, &top_cpuset
) {
810 if (cp
== &top_cpuset
)
813 * Continue traversing beyond @cp iff @cp has some CPUs and
814 * isn't load balancing. The former is obvious. The
815 * latter: All child cpusets contain a subset of the
816 * parent's cpus, so just skip them, and then we call
817 * update_domain_attr_tree() to calc relax_domain_level of
818 * the corresponding sched domain.
820 * If root is load-balancing, we can skip @cp if it
821 * is a subset of the root's effective_cpus.
823 if (!cpumask_empty(cp
->cpus_allowed
) &&
824 !(is_sched_load_balance(cp
) &&
825 cpumask_intersects(cp
->cpus_allowed
,
826 housekeeping_cpumask(HK_FLAG_DOMAIN
))))
829 if (root_load_balance
&&
830 cpumask_subset(cp
->cpus_allowed
, top_cpuset
.effective_cpus
))
833 if (is_sched_load_balance(cp
) &&
834 !cpumask_empty(cp
->effective_cpus
))
837 /* skip @cp's subtree if not a partition root */
838 if (!is_partition_root(cp
))
839 pos_css
= css_rightmost_descendant(pos_css
);
843 for (i
= 0; i
< csn
; i
++)
848 /* Find the best partition (set of sched domains) */
849 for (i
= 0; i
< csn
; i
++) {
850 struct cpuset
*a
= csa
[i
];
853 for (j
= 0; j
< csn
; j
++) {
854 struct cpuset
*b
= csa
[j
];
857 if (apn
!= bpn
&& cpusets_overlap(a
, b
)) {
858 for (k
= 0; k
< csn
; k
++) {
859 struct cpuset
*c
= csa
[k
];
864 ndoms
--; /* one less element */
871 * Now we know how many domains to create.
872 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
874 doms
= alloc_sched_domains(ndoms
);
879 * The rest of the code, including the scheduler, can deal with
880 * dattr==NULL case. No need to abort if alloc fails.
882 dattr
= kmalloc_array(ndoms
, sizeof(struct sched_domain_attr
),
885 for (nslot
= 0, i
= 0; i
< csn
; i
++) {
886 struct cpuset
*a
= csa
[i
];
891 /* Skip completed partitions */
897 if (nslot
== ndoms
) {
898 static int warnings
= 10;
900 pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
901 nslot
, ndoms
, csn
, i
, apn
);
909 *(dattr
+ nslot
) = SD_ATTR_INIT
;
910 for (j
= i
; j
< csn
; j
++) {
911 struct cpuset
*b
= csa
[j
];
914 cpumask_or(dp
, dp
, b
->effective_cpus
);
915 cpumask_and(dp
, dp
, housekeeping_cpumask(HK_FLAG_DOMAIN
));
917 update_domain_attr_tree(dattr
+ nslot
, b
);
919 /* Done with this partition */
925 BUG_ON(nslot
!= ndoms
);
931 * Fallback to the default domain if kmalloc() failed.
932 * See comments in partition_sched_domains().
942 static void update_tasks_root_domain(struct cpuset
*cs
)
944 struct css_task_iter it
;
945 struct task_struct
*task
;
947 css_task_iter_start(&cs
->css
, 0, &it
);
949 while ((task
= css_task_iter_next(&it
)))
950 dl_add_task_root_domain(task
);
952 css_task_iter_end(&it
);
955 static void rebuild_root_domains(void)
957 struct cpuset
*cs
= NULL
;
958 struct cgroup_subsys_state
*pos_css
;
960 percpu_rwsem_assert_held(&cpuset_rwsem
);
961 lockdep_assert_cpus_held();
962 lockdep_assert_held(&sched_domains_mutex
);
967 * Clear default root domain DL accounting, it will be computed again
968 * if a task belongs to it.
970 dl_clear_root_domain(&def_root_domain
);
972 cpuset_for_each_descendant_pre(cs
, pos_css
, &top_cpuset
) {
974 if (cpumask_empty(cs
->effective_cpus
)) {
975 pos_css
= css_rightmost_descendant(pos_css
);
983 update_tasks_root_domain(cs
);
992 partition_and_rebuild_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
993 struct sched_domain_attr
*dattr_new
)
995 mutex_lock(&sched_domains_mutex
);
996 partition_sched_domains_locked(ndoms_new
, doms_new
, dattr_new
);
997 rebuild_root_domains();
998 mutex_unlock(&sched_domains_mutex
);
1002 * Rebuild scheduler domains.
1004 * If the flag 'sched_load_balance' of any cpuset with non-empty
1005 * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
1006 * which has that flag enabled, or if any cpuset with a non-empty
1007 * 'cpus' is removed, then call this routine to rebuild the
1008 * scheduler's dynamic sched domains.
1010 * Call with cpuset_rwsem held. Takes cpus_read_lock().
1012 static void rebuild_sched_domains_locked(void)
1014 struct cgroup_subsys_state
*pos_css
;
1015 struct sched_domain_attr
*attr
;
1016 cpumask_var_t
*doms
;
1020 lockdep_assert_cpus_held();
1021 percpu_rwsem_assert_held(&cpuset_rwsem
);
1024 * If we have raced with CPU hotplug, return early to avoid
1025 * passing doms with offlined cpu to partition_sched_domains().
1026 * Anyways, cpuset_hotplug_workfn() will rebuild sched domains.
1028 * With no CPUs in any subpartitions, top_cpuset's effective CPUs
1029 * should be the same as the active CPUs, so checking only top_cpuset
1030 * is enough to detect racing CPU offlines.
1032 if (!top_cpuset
.nr_subparts_cpus
&&
1033 !cpumask_equal(top_cpuset
.effective_cpus
, cpu_active_mask
))
1037 * With subpartition CPUs, however, the effective CPUs of a partition
1038 * root should be only a subset of the active CPUs. Since a CPU in any
1039 * partition root could be offlined, all must be checked.
1041 if (top_cpuset
.nr_subparts_cpus
) {
1043 cpuset_for_each_descendant_pre(cs
, pos_css
, &top_cpuset
) {
1044 if (!is_partition_root(cs
)) {
1045 pos_css
= css_rightmost_descendant(pos_css
);
1048 if (!cpumask_subset(cs
->effective_cpus
,
1057 /* Generate domain masks and attrs */
1058 ndoms
= generate_sched_domains(&doms
, &attr
);
1060 /* Have scheduler rebuild the domains */
1061 partition_and_rebuild_sched_domains(ndoms
, doms
, attr
);
1063 #else /* !CONFIG_SMP */
1064 static void rebuild_sched_domains_locked(void)
1067 #endif /* CONFIG_SMP */
1069 void rebuild_sched_domains(void)
1072 percpu_down_write(&cpuset_rwsem
);
1073 rebuild_sched_domains_locked();
1074 percpu_up_write(&cpuset_rwsem
);
1079 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
1080 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
1082 * Iterate through each task of @cs updating its cpus_allowed to the
1083 * effective cpuset's. As this function is called with cpuset_rwsem held,
1084 * cpuset membership stays stable.
1086 static void update_tasks_cpumask(struct cpuset
*cs
)
1088 struct css_task_iter it
;
1089 struct task_struct
*task
;
1091 css_task_iter_start(&cs
->css
, 0, &it
);
1092 while ((task
= css_task_iter_next(&it
)))
1093 set_cpus_allowed_ptr(task
, cs
->effective_cpus
);
1094 css_task_iter_end(&it
);
1098 * compute_effective_cpumask - Compute the effective cpumask of the cpuset
1099 * @new_cpus: the temp variable for the new effective_cpus mask
1100 * @cs: the cpuset the need to recompute the new effective_cpus mask
1101 * @parent: the parent cpuset
1103 * If the parent has subpartition CPUs, include them in the list of
1104 * allowable CPUs in computing the new effective_cpus mask. Since offlined
1105 * CPUs are not removed from subparts_cpus, we have to use cpu_active_mask
1106 * to mask those out.
1108 static void compute_effective_cpumask(struct cpumask
*new_cpus
,
1109 struct cpuset
*cs
, struct cpuset
*parent
)
1111 if (parent
->nr_subparts_cpus
) {
1112 cpumask_or(new_cpus
, parent
->effective_cpus
,
1113 parent
->subparts_cpus
);
1114 cpumask_and(new_cpus
, new_cpus
, cs
->cpus_allowed
);
1115 cpumask_and(new_cpus
, new_cpus
, cpu_active_mask
);
1117 cpumask_and(new_cpus
, cs
->cpus_allowed
, parent
->effective_cpus
);
1122 * Commands for update_parent_subparts_cpumask
1125 partcmd_enable
, /* Enable partition root */
1126 partcmd_disable
, /* Disable partition root */
1127 partcmd_update
, /* Update parent's subparts_cpus */
1131 * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
1132 * @cpuset: The cpuset that requests change in partition root state
1133 * @cmd: Partition root state change command
1134 * @newmask: Optional new cpumask for partcmd_update
1135 * @tmp: Temporary addmask and delmask
1136 * Return: 0, 1 or an error code
1138 * For partcmd_enable, the cpuset is being transformed from a non-partition
1139 * root to a partition root. The cpus_allowed mask of the given cpuset will
1140 * be put into parent's subparts_cpus and taken away from parent's
1141 * effective_cpus. The function will return 0 if all the CPUs listed in
1142 * cpus_allowed can be granted or an error code will be returned.
1144 * For partcmd_disable, the cpuset is being transofrmed from a partition
1145 * root back to a non-partition root. Any CPUs in cpus_allowed that are in
1146 * parent's subparts_cpus will be taken away from that cpumask and put back
1147 * into parent's effective_cpus. 0 should always be returned.
1149 * For partcmd_update, if the optional newmask is specified, the cpu
1150 * list is to be changed from cpus_allowed to newmask. Otherwise,
1151 * cpus_allowed is assumed to remain the same. The cpuset should either
1152 * be a partition root or an invalid partition root. The partition root
1153 * state may change if newmask is NULL and none of the requested CPUs can
1154 * be granted by the parent. The function will return 1 if changes to
1155 * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
1156 * Error code should only be returned when newmask is non-NULL.
1158 * The partcmd_enable and partcmd_disable commands are used by
1159 * update_prstate(). The partcmd_update command is used by
1160 * update_cpumasks_hier() with newmask NULL and update_cpumask() with
1163 * The checking is more strict when enabling partition root than the
1164 * other two commands.
1166 * Because of the implicit cpu exclusive nature of a partition root,
1167 * cpumask changes that violates the cpu exclusivity rule will not be
1168 * permitted when checked by validate_change(). The validate_change()
1169 * function will also prevent any changes to the cpu list if it is not
1170 * a superset of children's cpu lists.
1172 static int update_parent_subparts_cpumask(struct cpuset
*cpuset
, int cmd
,
1173 struct cpumask
*newmask
,
1174 struct tmpmasks
*tmp
)
1176 struct cpuset
*parent
= parent_cs(cpuset
);
1177 int adding
; /* Moving cpus from effective_cpus to subparts_cpus */
1178 int deleting
; /* Moving cpus from subparts_cpus to effective_cpus */
1179 int old_prs
, new_prs
;
1180 bool part_error
= false; /* Partition error? */
1182 percpu_rwsem_assert_held(&cpuset_rwsem
);
1185 * The parent must be a partition root.
1186 * The new cpumask, if present, or the current cpus_allowed must
1189 if (!is_partition_root(parent
) ||
1190 (newmask
&& cpumask_empty(newmask
)) ||
1191 (!newmask
&& cpumask_empty(cpuset
->cpus_allowed
)))
1195 * Enabling/disabling partition root is not allowed if there are
1198 if ((cmd
!= partcmd_update
) && css_has_online_children(&cpuset
->css
))
1202 * Enabling partition root is not allowed if not all the CPUs
1203 * can be granted from parent's effective_cpus or at least one
1204 * CPU will be left after that.
1206 if ((cmd
== partcmd_enable
) &&
1207 (!cpumask_subset(cpuset
->cpus_allowed
, parent
->effective_cpus
) ||
1208 cpumask_equal(cpuset
->cpus_allowed
, parent
->effective_cpus
)))
1212 * A cpumask update cannot make parent's effective_cpus become empty.
1214 adding
= deleting
= false;
1215 old_prs
= new_prs
= cpuset
->partition_root_state
;
1216 if (cmd
== partcmd_enable
) {
1217 cpumask_copy(tmp
->addmask
, cpuset
->cpus_allowed
);
1219 } else if (cmd
== partcmd_disable
) {
1220 deleting
= cpumask_and(tmp
->delmask
, cpuset
->cpus_allowed
,
1221 parent
->subparts_cpus
);
1222 } else if (newmask
) {
1224 * partcmd_update with newmask:
1226 * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
1227 * addmask = newmask & parent->effective_cpus
1228 * & ~parent->subparts_cpus
1230 cpumask_andnot(tmp
->delmask
, cpuset
->cpus_allowed
, newmask
);
1231 deleting
= cpumask_and(tmp
->delmask
, tmp
->delmask
,
1232 parent
->subparts_cpus
);
1234 cpumask_and(tmp
->addmask
, newmask
, parent
->effective_cpus
);
1235 adding
= cpumask_andnot(tmp
->addmask
, tmp
->addmask
,
1236 parent
->subparts_cpus
);
1238 * Return error if the new effective_cpus could become empty.
1241 cpumask_equal(parent
->effective_cpus
, tmp
->addmask
)) {
1245 * As some of the CPUs in subparts_cpus might have
1246 * been offlined, we need to compute the real delmask
1249 if (!cpumask_and(tmp
->addmask
, tmp
->delmask
,
1252 cpumask_copy(tmp
->addmask
, parent
->effective_cpus
);
1256 * partcmd_update w/o newmask:
1258 * addmask = cpus_allowed & parent->effective_cpus
1260 * Note that parent's subparts_cpus may have been
1261 * pre-shrunk in case there is a change in the cpu list.
1262 * So no deletion is needed.
1264 adding
= cpumask_and(tmp
->addmask
, cpuset
->cpus_allowed
,
1265 parent
->effective_cpus
);
1266 part_error
= cpumask_equal(tmp
->addmask
,
1267 parent
->effective_cpus
);
1270 if (cmd
== partcmd_update
) {
1271 int prev_prs
= cpuset
->partition_root_state
;
1274 * Check for possible transition between PRS_ENABLED
1277 switch (cpuset
->partition_root_state
) {
1280 new_prs
= PRS_ERROR
;
1284 new_prs
= PRS_ENABLED
;
1288 * Set part_error if previously in invalid state.
1290 part_error
= (prev_prs
== PRS_ERROR
);
1293 if (!part_error
&& (new_prs
== PRS_ERROR
))
1294 return 0; /* Nothing need to be done */
1296 if (new_prs
== PRS_ERROR
) {
1298 * Remove all its cpus from parent's subparts_cpus.
1301 deleting
= cpumask_and(tmp
->delmask
, cpuset
->cpus_allowed
,
1302 parent
->subparts_cpus
);
1305 if (!adding
&& !deleting
&& (new_prs
== old_prs
))
1309 * Change the parent's subparts_cpus.
1310 * Newly added CPUs will be removed from effective_cpus and
1311 * newly deleted ones will be added back to effective_cpus.
1313 spin_lock_irq(&callback_lock
);
1315 cpumask_or(parent
->subparts_cpus
,
1316 parent
->subparts_cpus
, tmp
->addmask
);
1317 cpumask_andnot(parent
->effective_cpus
,
1318 parent
->effective_cpus
, tmp
->addmask
);
1321 cpumask_andnot(parent
->subparts_cpus
,
1322 parent
->subparts_cpus
, tmp
->delmask
);
1324 * Some of the CPUs in subparts_cpus might have been offlined.
1326 cpumask_and(tmp
->delmask
, tmp
->delmask
, cpu_active_mask
);
1327 cpumask_or(parent
->effective_cpus
,
1328 parent
->effective_cpus
, tmp
->delmask
);
1331 parent
->nr_subparts_cpus
= cpumask_weight(parent
->subparts_cpus
);
1333 if (old_prs
!= new_prs
)
1334 cpuset
->partition_root_state
= new_prs
;
1336 spin_unlock_irq(&callback_lock
);
1337 notify_partition_change(cpuset
, old_prs
, new_prs
);
1339 return cmd
== partcmd_update
;
1343 * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
1344 * @cs: the cpuset to consider
1345 * @tmp: temp variables for calculating effective_cpus & partition setup
1347 * When configured cpumask is changed, the effective cpumasks of this cpuset
1348 * and all its descendants need to be updated.
1350 * On legacy hierarchy, effective_cpus will be the same with cpu_allowed.
1352 * Called with cpuset_rwsem held
1354 static void update_cpumasks_hier(struct cpuset
*cs
, struct tmpmasks
*tmp
)
1357 struct cgroup_subsys_state
*pos_css
;
1358 bool need_rebuild_sched_domains
= false;
1359 int old_prs
, new_prs
;
1362 cpuset_for_each_descendant_pre(cp
, pos_css
, cs
) {
1363 struct cpuset
*parent
= parent_cs(cp
);
1365 compute_effective_cpumask(tmp
->new_cpus
, cp
, parent
);
1368 * If it becomes empty, inherit the effective mask of the
1369 * parent, which is guaranteed to have some CPUs.
1371 if (is_in_v2_mode() && cpumask_empty(tmp
->new_cpus
)) {
1372 cpumask_copy(tmp
->new_cpus
, parent
->effective_cpus
);
1373 if (!cp
->use_parent_ecpus
) {
1374 cp
->use_parent_ecpus
= true;
1375 parent
->child_ecpus_count
++;
1377 } else if (cp
->use_parent_ecpus
) {
1378 cp
->use_parent_ecpus
= false;
1379 WARN_ON_ONCE(!parent
->child_ecpus_count
);
1380 parent
->child_ecpus_count
--;
1384 * Skip the whole subtree if the cpumask remains the same
1385 * and has no partition root state.
1387 if (!cp
->partition_root_state
&&
1388 cpumask_equal(tmp
->new_cpus
, cp
->effective_cpus
)) {
1389 pos_css
= css_rightmost_descendant(pos_css
);
1394 * update_parent_subparts_cpumask() should have been called
1395 * for cs already in update_cpumask(). We should also call
1396 * update_tasks_cpumask() again for tasks in the parent
1397 * cpuset if the parent's subparts_cpus changes.
1399 old_prs
= new_prs
= cp
->partition_root_state
;
1400 if ((cp
!= cs
) && old_prs
) {
1401 switch (parent
->partition_root_state
) {
1404 * If parent is not a partition root or an
1405 * invalid partition root, clear its state
1406 * and its CS_CPU_EXCLUSIVE flag.
1408 WARN_ON_ONCE(cp
->partition_root_state
1410 new_prs
= PRS_DISABLED
;
1413 * clear_bit() is an atomic operation and
1414 * readers aren't interested in the state
1415 * of CS_CPU_EXCLUSIVE anyway. So we can
1416 * just update the flag without holding
1417 * the callback_lock.
1419 clear_bit(CS_CPU_EXCLUSIVE
, &cp
->flags
);
1423 if (update_parent_subparts_cpumask(cp
, partcmd_update
, NULL
, tmp
))
1424 update_tasks_cpumask(parent
);
1429 * When parent is invalid, it has to be too.
1431 new_prs
= PRS_ERROR
;
1436 if (!css_tryget_online(&cp
->css
))
1440 spin_lock_irq(&callback_lock
);
1442 cpumask_copy(cp
->effective_cpus
, tmp
->new_cpus
);
1443 if (cp
->nr_subparts_cpus
&& (new_prs
!= PRS_ENABLED
)) {
1444 cp
->nr_subparts_cpus
= 0;
1445 cpumask_clear(cp
->subparts_cpus
);
1446 } else if (cp
->nr_subparts_cpus
) {
1448 * Make sure that effective_cpus & subparts_cpus
1449 * are mutually exclusive.
1451 * In the unlikely event that effective_cpus
1452 * becomes empty. we clear cp->nr_subparts_cpus and
1453 * let its child partition roots to compete for
1456 cpumask_andnot(cp
->effective_cpus
, cp
->effective_cpus
,
1458 if (cpumask_empty(cp
->effective_cpus
)) {
1459 cpumask_copy(cp
->effective_cpus
, tmp
->new_cpus
);
1460 cpumask_clear(cp
->subparts_cpus
);
1461 cp
->nr_subparts_cpus
= 0;
1462 } else if (!cpumask_subset(cp
->subparts_cpus
,
1464 cpumask_andnot(cp
->subparts_cpus
,
1465 cp
->subparts_cpus
, tmp
->new_cpus
);
1466 cp
->nr_subparts_cpus
1467 = cpumask_weight(cp
->subparts_cpus
);
1471 if (new_prs
!= old_prs
)
1472 cp
->partition_root_state
= new_prs
;
1474 spin_unlock_irq(&callback_lock
);
1475 notify_partition_change(cp
, old_prs
, new_prs
);
1477 WARN_ON(!is_in_v2_mode() &&
1478 !cpumask_equal(cp
->cpus_allowed
, cp
->effective_cpus
));
1480 update_tasks_cpumask(cp
);
1483 * On legacy hierarchy, if the effective cpumask of any non-
1484 * empty cpuset is changed, we need to rebuild sched domains.
1485 * On default hierarchy, the cpuset needs to be a partition
1488 if (!cpumask_empty(cp
->cpus_allowed
) &&
1489 is_sched_load_balance(cp
) &&
1490 (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys
) ||
1491 is_partition_root(cp
)))
1492 need_rebuild_sched_domains
= true;
1499 if (need_rebuild_sched_domains
)
1500 rebuild_sched_domains_locked();
1504 * update_sibling_cpumasks - Update siblings cpumasks
1505 * @parent: Parent cpuset
1506 * @cs: Current cpuset
1507 * @tmp: Temp variables
1509 static void update_sibling_cpumasks(struct cpuset
*parent
, struct cpuset
*cs
,
1510 struct tmpmasks
*tmp
)
1512 struct cpuset
*sibling
;
1513 struct cgroup_subsys_state
*pos_css
;
1515 percpu_rwsem_assert_held(&cpuset_rwsem
);
1518 * Check all its siblings and call update_cpumasks_hier()
1519 * if their use_parent_ecpus flag is set in order for them
1520 * to use the right effective_cpus value.
1522 * The update_cpumasks_hier() function may sleep. So we have to
1523 * release the RCU read lock before calling it.
1526 cpuset_for_each_child(sibling
, pos_css
, parent
) {
1529 if (!sibling
->use_parent_ecpus
)
1531 if (!css_tryget_online(&sibling
->css
))
1535 update_cpumasks_hier(sibling
, tmp
);
1537 css_put(&sibling
->css
);
1543 * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
1544 * @cs: the cpuset to consider
1545 * @trialcs: trial cpuset
1546 * @buf: buffer of cpu numbers written to this cpuset
1548 static int update_cpumask(struct cpuset
*cs
, struct cpuset
*trialcs
,
1552 struct tmpmasks tmp
;
1554 /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
1555 if (cs
== &top_cpuset
)
1559 * An empty cpus_allowed is ok only if the cpuset has no tasks.
1560 * Since cpulist_parse() fails on an empty mask, we special case
1561 * that parsing. The validate_change() call ensures that cpusets
1562 * with tasks have cpus.
1565 cpumask_clear(trialcs
->cpus_allowed
);
1567 retval
= cpulist_parse(buf
, trialcs
->cpus_allowed
);
1571 if (!cpumask_subset(trialcs
->cpus_allowed
,
1572 top_cpuset
.cpus_allowed
))
1576 /* Nothing to do if the cpus didn't change */
1577 if (cpumask_equal(cs
->cpus_allowed
, trialcs
->cpus_allowed
))
1580 retval
= validate_change(cs
, trialcs
);
1584 #ifdef CONFIG_CPUMASK_OFFSTACK
1586 * Use the cpumasks in trialcs for tmpmasks when they are pointers
1587 * to allocated cpumasks.
1589 tmp
.addmask
= trialcs
->subparts_cpus
;
1590 tmp
.delmask
= trialcs
->effective_cpus
;
1591 tmp
.new_cpus
= trialcs
->cpus_allowed
;
1594 if (cs
->partition_root_state
) {
1595 /* Cpumask of a partition root cannot be empty */
1596 if (cpumask_empty(trialcs
->cpus_allowed
))
1598 if (update_parent_subparts_cpumask(cs
, partcmd_update
,
1599 trialcs
->cpus_allowed
, &tmp
) < 0)
1603 spin_lock_irq(&callback_lock
);
1604 cpumask_copy(cs
->cpus_allowed
, trialcs
->cpus_allowed
);
1607 * Make sure that subparts_cpus is a subset of cpus_allowed.
1609 if (cs
->nr_subparts_cpus
) {
1610 cpumask_and(cs
->subparts_cpus
, cs
->subparts_cpus
, cs
->cpus_allowed
);
1611 cs
->nr_subparts_cpus
= cpumask_weight(cs
->subparts_cpus
);
1613 spin_unlock_irq(&callback_lock
);
1615 update_cpumasks_hier(cs
, &tmp
);
1617 if (cs
->partition_root_state
) {
1618 struct cpuset
*parent
= parent_cs(cs
);
1621 * For partition root, update the cpumasks of sibling
1622 * cpusets if they use parent's effective_cpus.
1624 if (parent
->child_ecpus_count
)
1625 update_sibling_cpumasks(parent
, cs
, &tmp
);
1631 * Migrate memory region from one set of nodes to another. This is
1632 * performed asynchronously as it can be called from process migration path
1633 * holding locks involved in process management. All mm migrations are
1634 * performed in the queued order and can be waited for by flushing
1635 * cpuset_migrate_mm_wq.
1638 struct cpuset_migrate_mm_work
{
1639 struct work_struct work
;
1640 struct mm_struct
*mm
;
1645 static void cpuset_migrate_mm_workfn(struct work_struct
*work
)
1647 struct cpuset_migrate_mm_work
*mwork
=
1648 container_of(work
, struct cpuset_migrate_mm_work
, work
);
1650 /* on a wq worker, no need to worry about %current's mems_allowed */
1651 do_migrate_pages(mwork
->mm
, &mwork
->from
, &mwork
->to
, MPOL_MF_MOVE_ALL
);
1656 static void cpuset_migrate_mm(struct mm_struct
*mm
, const nodemask_t
*from
,
1657 const nodemask_t
*to
)
1659 struct cpuset_migrate_mm_work
*mwork
;
1661 if (nodes_equal(*from
, *to
)) {
1666 mwork
= kzalloc(sizeof(*mwork
), GFP_KERNEL
);
1669 mwork
->from
= *from
;
1671 INIT_WORK(&mwork
->work
, cpuset_migrate_mm_workfn
);
1672 queue_work(cpuset_migrate_mm_wq
, &mwork
->work
);
1678 static void cpuset_post_attach(void)
1680 flush_workqueue(cpuset_migrate_mm_wq
);
1684 * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
1685 * @tsk: the task to change
1686 * @newmems: new nodes that the task will be set
1688 * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
1689 * and rebind an eventual tasks' mempolicy. If the task is allocating in
1690 * parallel, it might temporarily see an empty intersection, which results in
1691 * a seqlock check and retry before OOM or allocation failure.
1693 static void cpuset_change_task_nodemask(struct task_struct
*tsk
,
1694 nodemask_t
*newmems
)
1698 local_irq_disable();
1699 write_seqcount_begin(&tsk
->mems_allowed_seq
);
1701 nodes_or(tsk
->mems_allowed
, tsk
->mems_allowed
, *newmems
);
1702 mpol_rebind_task(tsk
, newmems
);
1703 tsk
->mems_allowed
= *newmems
;
1705 write_seqcount_end(&tsk
->mems_allowed_seq
);
1711 static void *cpuset_being_rebound
;
1714 * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
1715 * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
1717 * Iterate through each task of @cs updating its mems_allowed to the
1718 * effective cpuset's. As this function is called with cpuset_rwsem held,
1719 * cpuset membership stays stable.
1721 static void update_tasks_nodemask(struct cpuset
*cs
)
1723 static nodemask_t newmems
; /* protected by cpuset_rwsem */
1724 struct css_task_iter it
;
1725 struct task_struct
*task
;
1727 cpuset_being_rebound
= cs
; /* causes mpol_dup() rebind */
1729 guarantee_online_mems(cs
, &newmems
);
1732 * The mpol_rebind_mm() call takes mmap_lock, which we couldn't
1733 * take while holding tasklist_lock. Forks can happen - the
1734 * mpol_dup() cpuset_being_rebound check will catch such forks,
1735 * and rebind their vma mempolicies too. Because we still hold
1736 * the global cpuset_rwsem, we know that no other rebind effort
1737 * will be contending for the global variable cpuset_being_rebound.
1738 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
1739 * is idempotent. Also migrate pages in each mm to new nodes.
1741 css_task_iter_start(&cs
->css
, 0, &it
);
1742 while ((task
= css_task_iter_next(&it
))) {
1743 struct mm_struct
*mm
;
1746 cpuset_change_task_nodemask(task
, &newmems
);
1748 mm
= get_task_mm(task
);
1752 migrate
= is_memory_migrate(cs
);
1754 mpol_rebind_mm(mm
, &cs
->mems_allowed
);
1756 cpuset_migrate_mm(mm
, &cs
->old_mems_allowed
, &newmems
);
1760 css_task_iter_end(&it
);
1763 * All the tasks' nodemasks have been updated, update
1764 * cs->old_mems_allowed.
1766 cs
->old_mems_allowed
= newmems
;
1768 /* We're done rebinding vmas to this cpuset's new mems_allowed. */
1769 cpuset_being_rebound
= NULL
;
1773 * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
1774 * @cs: the cpuset to consider
1775 * @new_mems: a temp variable for calculating new effective_mems
1777 * When configured nodemask is changed, the effective nodemasks of this cpuset
1778 * and all its descendants need to be updated.
1780 * On legacy hierarchy, effective_mems will be the same with mems_allowed.
1782 * Called with cpuset_rwsem held
1784 static void update_nodemasks_hier(struct cpuset
*cs
, nodemask_t
*new_mems
)
1787 struct cgroup_subsys_state
*pos_css
;
1790 cpuset_for_each_descendant_pre(cp
, pos_css
, cs
) {
1791 struct cpuset
*parent
= parent_cs(cp
);
1793 nodes_and(*new_mems
, cp
->mems_allowed
, parent
->effective_mems
);
1796 * If it becomes empty, inherit the effective mask of the
1797 * parent, which is guaranteed to have some MEMs.
1799 if (is_in_v2_mode() && nodes_empty(*new_mems
))
1800 *new_mems
= parent
->effective_mems
;
1802 /* Skip the whole subtree if the nodemask remains the same. */
1803 if (nodes_equal(*new_mems
, cp
->effective_mems
)) {
1804 pos_css
= css_rightmost_descendant(pos_css
);
1808 if (!css_tryget_online(&cp
->css
))
1812 spin_lock_irq(&callback_lock
);
1813 cp
->effective_mems
= *new_mems
;
1814 spin_unlock_irq(&callback_lock
);
1816 WARN_ON(!is_in_v2_mode() &&
1817 !nodes_equal(cp
->mems_allowed
, cp
->effective_mems
));
1819 update_tasks_nodemask(cp
);
1828 * Handle user request to change the 'mems' memory placement
1829 * of a cpuset. Needs to validate the request, update the
1830 * cpusets mems_allowed, and for each task in the cpuset,
1831 * update mems_allowed and rebind task's mempolicy and any vma
1832 * mempolicies and if the cpuset is marked 'memory_migrate',
1833 * migrate the tasks pages to the new memory.
1835 * Call with cpuset_rwsem held. May take callback_lock during call.
1836 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
1837 * lock each such tasks mm->mmap_lock, scan its vma's and rebind
1838 * their mempolicies to the cpusets new mems_allowed.
1840 static int update_nodemask(struct cpuset
*cs
, struct cpuset
*trialcs
,
1846 * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
1849 if (cs
== &top_cpuset
) {
1855 * An empty mems_allowed is ok iff there are no tasks in the cpuset.
1856 * Since nodelist_parse() fails on an empty mask, we special case
1857 * that parsing. The validate_change() call ensures that cpusets
1858 * with tasks have memory.
1861 nodes_clear(trialcs
->mems_allowed
);
1863 retval
= nodelist_parse(buf
, trialcs
->mems_allowed
);
1867 if (!nodes_subset(trialcs
->mems_allowed
,
1868 top_cpuset
.mems_allowed
)) {
1874 if (nodes_equal(cs
->mems_allowed
, trialcs
->mems_allowed
)) {
1875 retval
= 0; /* Too easy - nothing to do */
1878 retval
= validate_change(cs
, trialcs
);
1882 spin_lock_irq(&callback_lock
);
1883 cs
->mems_allowed
= trialcs
->mems_allowed
;
1884 spin_unlock_irq(&callback_lock
);
1886 /* use trialcs->mems_allowed as a temp variable */
1887 update_nodemasks_hier(cs
, &trialcs
->mems_allowed
);
1892 bool current_cpuset_is_being_rebound(void)
1897 ret
= task_cs(current
) == cpuset_being_rebound
;
1903 static int update_relax_domain_level(struct cpuset
*cs
, s64 val
)
1906 if (val
< -1 || val
>= sched_domain_level_max
)
1910 if (val
!= cs
->relax_domain_level
) {
1911 cs
->relax_domain_level
= val
;
1912 if (!cpumask_empty(cs
->cpus_allowed
) &&
1913 is_sched_load_balance(cs
))
1914 rebuild_sched_domains_locked();
1921 * update_tasks_flags - update the spread flags of tasks in the cpuset.
1922 * @cs: the cpuset in which each task's spread flags needs to be changed
1924 * Iterate through each task of @cs updating its spread flags. As this
1925 * function is called with cpuset_rwsem held, cpuset membership stays
1928 static void update_tasks_flags(struct cpuset
*cs
)
1930 struct css_task_iter it
;
1931 struct task_struct
*task
;
1933 css_task_iter_start(&cs
->css
, 0, &it
);
1934 while ((task
= css_task_iter_next(&it
)))
1935 cpuset_update_task_spread_flag(cs
, task
);
1936 css_task_iter_end(&it
);
1940 * update_flag - read a 0 or a 1 in a file and update associated flag
1941 * bit: the bit to update (see cpuset_flagbits_t)
1942 * cs: the cpuset to update
1943 * turning_on: whether the flag is being set or cleared
1945 * Call with cpuset_rwsem held.
1948 static int update_flag(cpuset_flagbits_t bit
, struct cpuset
*cs
,
1951 struct cpuset
*trialcs
;
1952 int balance_flag_changed
;
1953 int spread_flag_changed
;
1956 trialcs
= alloc_trial_cpuset(cs
);
1961 set_bit(bit
, &trialcs
->flags
);
1963 clear_bit(bit
, &trialcs
->flags
);
1965 err
= validate_change(cs
, trialcs
);
1969 balance_flag_changed
= (is_sched_load_balance(cs
) !=
1970 is_sched_load_balance(trialcs
));
1972 spread_flag_changed
= ((is_spread_slab(cs
) != is_spread_slab(trialcs
))
1973 || (is_spread_page(cs
) != is_spread_page(trialcs
)));
1975 spin_lock_irq(&callback_lock
);
1976 cs
->flags
= trialcs
->flags
;
1977 spin_unlock_irq(&callback_lock
);
1979 if (!cpumask_empty(trialcs
->cpus_allowed
) && balance_flag_changed
)
1980 rebuild_sched_domains_locked();
1982 if (spread_flag_changed
)
1983 update_tasks_flags(cs
);
1985 free_cpuset(trialcs
);
1990 * update_prstate - update partititon_root_state
1991 * cs: the cpuset to update
1992 * new_prs: new partition root state
1994 * Call with cpuset_rwsem held.
1996 static int update_prstate(struct cpuset
*cs
, int new_prs
)
1998 int err
, old_prs
= cs
->partition_root_state
;
1999 struct cpuset
*parent
= parent_cs(cs
);
2000 struct tmpmasks tmpmask
;
2002 if (old_prs
== new_prs
)
2006 * Cannot force a partial or invalid partition root to a full
2009 if (new_prs
&& (old_prs
== PRS_ERROR
))
2012 if (alloc_cpumasks(NULL
, &tmpmask
))
2018 * Turning on partition root requires setting the
2019 * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
2022 if (cpumask_empty(cs
->cpus_allowed
))
2025 err
= update_flag(CS_CPU_EXCLUSIVE
, cs
, 1);
2029 err
= update_parent_subparts_cpumask(cs
, partcmd_enable
,
2032 update_flag(CS_CPU_EXCLUSIVE
, cs
, 0);
2037 * Turning off partition root will clear the
2038 * CS_CPU_EXCLUSIVE bit.
2040 if (old_prs
== PRS_ERROR
) {
2041 update_flag(CS_CPU_EXCLUSIVE
, cs
, 0);
2046 err
= update_parent_subparts_cpumask(cs
, partcmd_disable
,
2051 /* Turning off CS_CPU_EXCLUSIVE will not return error */
2052 update_flag(CS_CPU_EXCLUSIVE
, cs
, 0);
2056 * Update cpumask of parent's tasks except when it is the top
2057 * cpuset as some system daemons cannot be mapped to other CPUs.
2059 if (parent
!= &top_cpuset
)
2060 update_tasks_cpumask(parent
);
2062 if (parent
->child_ecpus_count
)
2063 update_sibling_cpumasks(parent
, cs
, &tmpmask
);
2065 rebuild_sched_domains_locked();
2068 spin_lock_irq(&callback_lock
);
2069 cs
->partition_root_state
= new_prs
;
2070 spin_unlock_irq(&callback_lock
);
2071 notify_partition_change(cs
, old_prs
, new_prs
);
2074 free_cpumasks(NULL
, &tmpmask
);
2079 * Frequency meter - How fast is some event occurring?
2081 * These routines manage a digitally filtered, constant time based,
2082 * event frequency meter. There are four routines:
2083 * fmeter_init() - initialize a frequency meter.
2084 * fmeter_markevent() - called each time the event happens.
2085 * fmeter_getrate() - returns the recent rate of such events.
2086 * fmeter_update() - internal routine used to update fmeter.
2088 * A common data structure is passed to each of these routines,
2089 * which is used to keep track of the state required to manage the
2090 * frequency meter and its digital filter.
2092 * The filter works on the number of events marked per unit time.
2093 * The filter is single-pole low-pass recursive (IIR). The time unit
2094 * is 1 second. Arithmetic is done using 32-bit integers scaled to
2095 * simulate 3 decimal digits of precision (multiplied by 1000).
2097 * With an FM_COEF of 933, and a time base of 1 second, the filter
2098 * has a half-life of 10 seconds, meaning that if the events quit
2099 * happening, then the rate returned from the fmeter_getrate()
2100 * will be cut in half each 10 seconds, until it converges to zero.
2102 * It is not worth doing a real infinitely recursive filter. If more
2103 * than FM_MAXTICKS ticks have elapsed since the last filter event,
2104 * just compute FM_MAXTICKS ticks worth, by which point the level
2107 * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
2108 * arithmetic overflow in the fmeter_update() routine.
2110 * Given the simple 32 bit integer arithmetic used, this meter works
2111 * best for reporting rates between one per millisecond (msec) and
2112 * one per 32 (approx) seconds. At constant rates faster than one
2113 * per msec it maxes out at values just under 1,000,000. At constant
2114 * rates between one per msec, and one per second it will stabilize
2115 * to a value N*1000, where N is the rate of events per second.
2116 * At constant rates between one per second and one per 32 seconds,
2117 * it will be choppy, moving up on the seconds that have an event,
2118 * and then decaying until the next event. At rates slower than
2119 * about one in 32 seconds, it decays all the way back to zero between
2123 #define FM_COEF 933 /* coefficient for half-life of 10 secs */
2124 #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */
2125 #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
2126 #define FM_SCALE 1000 /* faux fixed point scale */
2128 /* Initialize a frequency meter */
2129 static void fmeter_init(struct fmeter
*fmp
)
2134 spin_lock_init(&fmp
->lock
);
2137 /* Internal meter update - process cnt events and update value */
2138 static void fmeter_update(struct fmeter
*fmp
)
2143 now
= ktime_get_seconds();
2144 ticks
= now
- fmp
->time
;
2149 ticks
= min(FM_MAXTICKS
, ticks
);
2151 fmp
->val
= (FM_COEF
* fmp
->val
) / FM_SCALE
;
2154 fmp
->val
+= ((FM_SCALE
- FM_COEF
) * fmp
->cnt
) / FM_SCALE
;
2158 /* Process any previous ticks, then bump cnt by one (times scale). */
2159 static void fmeter_markevent(struct fmeter
*fmp
)
2161 spin_lock(&fmp
->lock
);
2163 fmp
->cnt
= min(FM_MAXCNT
, fmp
->cnt
+ FM_SCALE
);
2164 spin_unlock(&fmp
->lock
);
2167 /* Process any previous ticks, then return current value. */
2168 static int fmeter_getrate(struct fmeter
*fmp
)
2172 spin_lock(&fmp
->lock
);
2175 spin_unlock(&fmp
->lock
);
2179 static struct cpuset
*cpuset_attach_old_cs
;
2181 /* Called by cgroups to determine if a cpuset is usable; cpuset_rwsem held */
2182 static int cpuset_can_attach(struct cgroup_taskset
*tset
)
2184 struct cgroup_subsys_state
*css
;
2186 struct task_struct
*task
;
2189 /* used later by cpuset_attach() */
2190 cpuset_attach_old_cs
= task_cs(cgroup_taskset_first(tset
, &css
));
2193 percpu_down_write(&cpuset_rwsem
);
2195 /* allow moving tasks into an empty cpuset if on default hierarchy */
2197 if (!is_in_v2_mode() &&
2198 (cpumask_empty(cs
->cpus_allowed
) || nodes_empty(cs
->mems_allowed
)))
2201 cgroup_taskset_for_each(task
, css
, tset
) {
2202 ret
= task_can_attach(task
, cs
->cpus_allowed
);
2205 ret
= security_task_setscheduler(task
);
2211 * Mark attach is in progress. This makes validate_change() fail
2212 * changes which zero cpus/mems_allowed.
2214 cs
->attach_in_progress
++;
2217 percpu_up_write(&cpuset_rwsem
);
2221 static void cpuset_cancel_attach(struct cgroup_taskset
*tset
)
2223 struct cgroup_subsys_state
*css
;
2225 cgroup_taskset_first(tset
, &css
);
2227 percpu_down_write(&cpuset_rwsem
);
2228 css_cs(css
)->attach_in_progress
--;
2229 percpu_up_write(&cpuset_rwsem
);
2233 * Protected by cpuset_rwsem. cpus_attach is used only by cpuset_attach()
2234 * but we can't allocate it dynamically there. Define it global and
2235 * allocate from cpuset_init().
2237 static cpumask_var_t cpus_attach
;
2239 static void cpuset_attach(struct cgroup_taskset
*tset
)
2241 /* static buf protected by cpuset_rwsem */
2242 static nodemask_t cpuset_attach_nodemask_to
;
2243 struct task_struct
*task
;
2244 struct task_struct
*leader
;
2245 struct cgroup_subsys_state
*css
;
2247 struct cpuset
*oldcs
= cpuset_attach_old_cs
;
2249 cgroup_taskset_first(tset
, &css
);
2253 percpu_down_write(&cpuset_rwsem
);
2255 guarantee_online_mems(cs
, &cpuset_attach_nodemask_to
);
2257 cgroup_taskset_for_each(task
, css
, tset
) {
2258 if (cs
!= &top_cpuset
)
2259 guarantee_online_cpus(task
, cpus_attach
);
2261 cpumask_copy(cpus_attach
, task_cpu_possible_mask(task
));
2263 * can_attach beforehand should guarantee that this doesn't
2264 * fail. TODO: have a better way to handle failure here
2266 WARN_ON_ONCE(set_cpus_allowed_ptr(task
, cpus_attach
));
2268 cpuset_change_task_nodemask(task
, &cpuset_attach_nodemask_to
);
2269 cpuset_update_task_spread_flag(cs
, task
);
2273 * Change mm for all threadgroup leaders. This is expensive and may
2274 * sleep and should be moved outside migration path proper.
2276 cpuset_attach_nodemask_to
= cs
->effective_mems
;
2277 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
2278 struct mm_struct
*mm
= get_task_mm(leader
);
2281 mpol_rebind_mm(mm
, &cpuset_attach_nodemask_to
);
2284 * old_mems_allowed is the same with mems_allowed
2285 * here, except if this task is being moved
2286 * automatically due to hotplug. In that case
2287 * @mems_allowed has been updated and is empty, so
2288 * @old_mems_allowed is the right nodesets that we
2291 if (is_memory_migrate(cs
))
2292 cpuset_migrate_mm(mm
, &oldcs
->old_mems_allowed
,
2293 &cpuset_attach_nodemask_to
);
2299 cs
->old_mems_allowed
= cpuset_attach_nodemask_to
;
2301 cs
->attach_in_progress
--;
2302 if (!cs
->attach_in_progress
)
2303 wake_up(&cpuset_attach_wq
);
2305 percpu_up_write(&cpuset_rwsem
);
2309 /* The various types of files and directories in a cpuset file system */
2312 FILE_MEMORY_MIGRATE
,
2315 FILE_EFFECTIVE_CPULIST
,
2316 FILE_EFFECTIVE_MEMLIST
,
2317 FILE_SUBPARTS_CPULIST
,
2321 FILE_SCHED_LOAD_BALANCE
,
2322 FILE_PARTITION_ROOT
,
2323 FILE_SCHED_RELAX_DOMAIN_LEVEL
,
2324 FILE_MEMORY_PRESSURE_ENABLED
,
2325 FILE_MEMORY_PRESSURE
,
2328 } cpuset_filetype_t
;
2330 static int cpuset_write_u64(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
2333 struct cpuset
*cs
= css_cs(css
);
2334 cpuset_filetype_t type
= cft
->private;
2338 percpu_down_write(&cpuset_rwsem
);
2339 if (!is_cpuset_online(cs
)) {
2345 case FILE_CPU_EXCLUSIVE
:
2346 retval
= update_flag(CS_CPU_EXCLUSIVE
, cs
, val
);
2348 case FILE_MEM_EXCLUSIVE
:
2349 retval
= update_flag(CS_MEM_EXCLUSIVE
, cs
, val
);
2351 case FILE_MEM_HARDWALL
:
2352 retval
= update_flag(CS_MEM_HARDWALL
, cs
, val
);
2354 case FILE_SCHED_LOAD_BALANCE
:
2355 retval
= update_flag(CS_SCHED_LOAD_BALANCE
, cs
, val
);
2357 case FILE_MEMORY_MIGRATE
:
2358 retval
= update_flag(CS_MEMORY_MIGRATE
, cs
, val
);
2360 case FILE_MEMORY_PRESSURE_ENABLED
:
2361 cpuset_memory_pressure_enabled
= !!val
;
2363 case FILE_SPREAD_PAGE
:
2364 retval
= update_flag(CS_SPREAD_PAGE
, cs
, val
);
2366 case FILE_SPREAD_SLAB
:
2367 retval
= update_flag(CS_SPREAD_SLAB
, cs
, val
);
2374 percpu_up_write(&cpuset_rwsem
);
2379 static int cpuset_write_s64(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
2382 struct cpuset
*cs
= css_cs(css
);
2383 cpuset_filetype_t type
= cft
->private;
2384 int retval
= -ENODEV
;
2387 percpu_down_write(&cpuset_rwsem
);
2388 if (!is_cpuset_online(cs
))
2392 case FILE_SCHED_RELAX_DOMAIN_LEVEL
:
2393 retval
= update_relax_domain_level(cs
, val
);
2400 percpu_up_write(&cpuset_rwsem
);
2406 * Common handling for a write to a "cpus" or "mems" file.
2408 static ssize_t
cpuset_write_resmask(struct kernfs_open_file
*of
,
2409 char *buf
, size_t nbytes
, loff_t off
)
2411 struct cpuset
*cs
= css_cs(of_css(of
));
2412 struct cpuset
*trialcs
;
2413 int retval
= -ENODEV
;
2415 buf
= strstrip(buf
);
2418 * CPU or memory hotunplug may leave @cs w/o any execution
2419 * resources, in which case the hotplug code asynchronously updates
2420 * configuration and transfers all tasks to the nearest ancestor
2421 * which can execute.
2423 * As writes to "cpus" or "mems" may restore @cs's execution
2424 * resources, wait for the previously scheduled operations before
2425 * proceeding, so that we don't end up keep removing tasks added
2426 * after execution capability is restored.
2428 * cpuset_hotplug_work calls back into cgroup core via
2429 * cgroup_transfer_tasks() and waiting for it from a cgroupfs
2430 * operation like this one can lead to a deadlock through kernfs
2431 * active_ref protection. Let's break the protection. Losing the
2432 * protection is okay as we check whether @cs is online after
2433 * grabbing cpuset_rwsem anyway. This only happens on the legacy
2437 kernfs_break_active_protection(of
->kn
);
2438 flush_work(&cpuset_hotplug_work
);
2441 percpu_down_write(&cpuset_rwsem
);
2442 if (!is_cpuset_online(cs
))
2445 trialcs
= alloc_trial_cpuset(cs
);
2451 switch (of_cft(of
)->private) {
2453 retval
= update_cpumask(cs
, trialcs
, buf
);
2456 retval
= update_nodemask(cs
, trialcs
, buf
);
2463 free_cpuset(trialcs
);
2465 percpu_up_write(&cpuset_rwsem
);
2467 kernfs_unbreak_active_protection(of
->kn
);
2469 flush_workqueue(cpuset_migrate_mm_wq
);
2470 return retval
?: nbytes
;
2474 * These ascii lists should be read in a single call, by using a user
2475 * buffer large enough to hold the entire map. If read in smaller
2476 * chunks, there is no guarantee of atomicity. Since the display format
2477 * used, list of ranges of sequential numbers, is variable length,
2478 * and since these maps can change value dynamically, one could read
2479 * gibberish by doing partial reads while a list was changing.
2481 static int cpuset_common_seq_show(struct seq_file
*sf
, void *v
)
2483 struct cpuset
*cs
= css_cs(seq_css(sf
));
2484 cpuset_filetype_t type
= seq_cft(sf
)->private;
2487 spin_lock_irq(&callback_lock
);
2491 seq_printf(sf
, "%*pbl\n", cpumask_pr_args(cs
->cpus_allowed
));
2494 seq_printf(sf
, "%*pbl\n", nodemask_pr_args(&cs
->mems_allowed
));
2496 case FILE_EFFECTIVE_CPULIST
:
2497 seq_printf(sf
, "%*pbl\n", cpumask_pr_args(cs
->effective_cpus
));
2499 case FILE_EFFECTIVE_MEMLIST
:
2500 seq_printf(sf
, "%*pbl\n", nodemask_pr_args(&cs
->effective_mems
));
2502 case FILE_SUBPARTS_CPULIST
:
2503 seq_printf(sf
, "%*pbl\n", cpumask_pr_args(cs
->subparts_cpus
));
2509 spin_unlock_irq(&callback_lock
);
2513 static u64
cpuset_read_u64(struct cgroup_subsys_state
*css
, struct cftype
*cft
)
2515 struct cpuset
*cs
= css_cs(css
);
2516 cpuset_filetype_t type
= cft
->private;
2518 case FILE_CPU_EXCLUSIVE
:
2519 return is_cpu_exclusive(cs
);
2520 case FILE_MEM_EXCLUSIVE
:
2521 return is_mem_exclusive(cs
);
2522 case FILE_MEM_HARDWALL
:
2523 return is_mem_hardwall(cs
);
2524 case FILE_SCHED_LOAD_BALANCE
:
2525 return is_sched_load_balance(cs
);
2526 case FILE_MEMORY_MIGRATE
:
2527 return is_memory_migrate(cs
);
2528 case FILE_MEMORY_PRESSURE_ENABLED
:
2529 return cpuset_memory_pressure_enabled
;
2530 case FILE_MEMORY_PRESSURE
:
2531 return fmeter_getrate(&cs
->fmeter
);
2532 case FILE_SPREAD_PAGE
:
2533 return is_spread_page(cs
);
2534 case FILE_SPREAD_SLAB
:
2535 return is_spread_slab(cs
);
2540 /* Unreachable but makes gcc happy */
2544 static s64
cpuset_read_s64(struct cgroup_subsys_state
*css
, struct cftype
*cft
)
2546 struct cpuset
*cs
= css_cs(css
);
2547 cpuset_filetype_t type
= cft
->private;
2549 case FILE_SCHED_RELAX_DOMAIN_LEVEL
:
2550 return cs
->relax_domain_level
;
2555 /* Unreachable but makes gcc happy */
2559 static int sched_partition_show(struct seq_file
*seq
, void *v
)
2561 struct cpuset
*cs
= css_cs(seq_css(seq
));
2563 switch (cs
->partition_root_state
) {
2565 seq_puts(seq
, "root\n");
2568 seq_puts(seq
, "member\n");
2571 seq_puts(seq
, "root invalid\n");
2577 static ssize_t
sched_partition_write(struct kernfs_open_file
*of
, char *buf
,
2578 size_t nbytes
, loff_t off
)
2580 struct cpuset
*cs
= css_cs(of_css(of
));
2582 int retval
= -ENODEV
;
2584 buf
= strstrip(buf
);
2587 * Convert "root" to ENABLED, and convert "member" to DISABLED.
2589 if (!strcmp(buf
, "root"))
2591 else if (!strcmp(buf
, "member"))
2598 percpu_down_write(&cpuset_rwsem
);
2599 if (!is_cpuset_online(cs
))
2602 retval
= update_prstate(cs
, val
);
2604 percpu_up_write(&cpuset_rwsem
);
2607 return retval
?: nbytes
;
2611 * for the common functions, 'private' gives the type of file
2614 static struct cftype legacy_files
[] = {
2617 .seq_show
= cpuset_common_seq_show
,
2618 .write
= cpuset_write_resmask
,
2619 .max_write_len
= (100U + 6 * NR_CPUS
),
2620 .private = FILE_CPULIST
,
2625 .seq_show
= cpuset_common_seq_show
,
2626 .write
= cpuset_write_resmask
,
2627 .max_write_len
= (100U + 6 * MAX_NUMNODES
),
2628 .private = FILE_MEMLIST
,
2632 .name
= "effective_cpus",
2633 .seq_show
= cpuset_common_seq_show
,
2634 .private = FILE_EFFECTIVE_CPULIST
,
2638 .name
= "effective_mems",
2639 .seq_show
= cpuset_common_seq_show
,
2640 .private = FILE_EFFECTIVE_MEMLIST
,
2644 .name
= "cpu_exclusive",
2645 .read_u64
= cpuset_read_u64
,
2646 .write_u64
= cpuset_write_u64
,
2647 .private = FILE_CPU_EXCLUSIVE
,
2651 .name
= "mem_exclusive",
2652 .read_u64
= cpuset_read_u64
,
2653 .write_u64
= cpuset_write_u64
,
2654 .private = FILE_MEM_EXCLUSIVE
,
2658 .name
= "mem_hardwall",
2659 .read_u64
= cpuset_read_u64
,
2660 .write_u64
= cpuset_write_u64
,
2661 .private = FILE_MEM_HARDWALL
,
2665 .name
= "sched_load_balance",
2666 .read_u64
= cpuset_read_u64
,
2667 .write_u64
= cpuset_write_u64
,
2668 .private = FILE_SCHED_LOAD_BALANCE
,
2672 .name
= "sched_relax_domain_level",
2673 .read_s64
= cpuset_read_s64
,
2674 .write_s64
= cpuset_write_s64
,
2675 .private = FILE_SCHED_RELAX_DOMAIN_LEVEL
,
2679 .name
= "memory_migrate",
2680 .read_u64
= cpuset_read_u64
,
2681 .write_u64
= cpuset_write_u64
,
2682 .private = FILE_MEMORY_MIGRATE
,
2686 .name
= "memory_pressure",
2687 .read_u64
= cpuset_read_u64
,
2688 .private = FILE_MEMORY_PRESSURE
,
2692 .name
= "memory_spread_page",
2693 .read_u64
= cpuset_read_u64
,
2694 .write_u64
= cpuset_write_u64
,
2695 .private = FILE_SPREAD_PAGE
,
2699 .name
= "memory_spread_slab",
2700 .read_u64
= cpuset_read_u64
,
2701 .write_u64
= cpuset_write_u64
,
2702 .private = FILE_SPREAD_SLAB
,
2706 .name
= "memory_pressure_enabled",
2707 .flags
= CFTYPE_ONLY_ON_ROOT
,
2708 .read_u64
= cpuset_read_u64
,
2709 .write_u64
= cpuset_write_u64
,
2710 .private = FILE_MEMORY_PRESSURE_ENABLED
,
2717 * This is currently a minimal set for the default hierarchy. It can be
2718 * expanded later on by migrating more features and control files from v1.
2720 static struct cftype dfl_files
[] = {
2723 .seq_show
= cpuset_common_seq_show
,
2724 .write
= cpuset_write_resmask
,
2725 .max_write_len
= (100U + 6 * NR_CPUS
),
2726 .private = FILE_CPULIST
,
2727 .flags
= CFTYPE_NOT_ON_ROOT
,
2732 .seq_show
= cpuset_common_seq_show
,
2733 .write
= cpuset_write_resmask
,
2734 .max_write_len
= (100U + 6 * MAX_NUMNODES
),
2735 .private = FILE_MEMLIST
,
2736 .flags
= CFTYPE_NOT_ON_ROOT
,
2740 .name
= "cpus.effective",
2741 .seq_show
= cpuset_common_seq_show
,
2742 .private = FILE_EFFECTIVE_CPULIST
,
2746 .name
= "mems.effective",
2747 .seq_show
= cpuset_common_seq_show
,
2748 .private = FILE_EFFECTIVE_MEMLIST
,
2752 .name
= "cpus.partition",
2753 .seq_show
= sched_partition_show
,
2754 .write
= sched_partition_write
,
2755 .private = FILE_PARTITION_ROOT
,
2756 .flags
= CFTYPE_NOT_ON_ROOT
,
2757 .file_offset
= offsetof(struct cpuset
, partition_file
),
2761 .name
= "cpus.subpartitions",
2762 .seq_show
= cpuset_common_seq_show
,
2763 .private = FILE_SUBPARTS_CPULIST
,
2764 .flags
= CFTYPE_DEBUG
,
2772 * cpuset_css_alloc - allocate a cpuset css
2773 * cgrp: control group that the new cpuset will be part of
2776 static struct cgroup_subsys_state
*
2777 cpuset_css_alloc(struct cgroup_subsys_state
*parent_css
)
2782 return &top_cpuset
.css
;
2784 cs
= kzalloc(sizeof(*cs
), GFP_KERNEL
);
2786 return ERR_PTR(-ENOMEM
);
2788 if (alloc_cpumasks(cs
, NULL
)) {
2790 return ERR_PTR(-ENOMEM
);
2793 __set_bit(CS_SCHED_LOAD_BALANCE
, &cs
->flags
);
2794 nodes_clear(cs
->mems_allowed
);
2795 nodes_clear(cs
->effective_mems
);
2796 fmeter_init(&cs
->fmeter
);
2797 cs
->relax_domain_level
= -1;
2799 /* Set CS_MEMORY_MIGRATE for default hierarchy */
2800 if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys
))
2801 __set_bit(CS_MEMORY_MIGRATE
, &cs
->flags
);
2806 static int cpuset_css_online(struct cgroup_subsys_state
*css
)
2808 struct cpuset
*cs
= css_cs(css
);
2809 struct cpuset
*parent
= parent_cs(cs
);
2810 struct cpuset
*tmp_cs
;
2811 struct cgroup_subsys_state
*pos_css
;
2817 percpu_down_write(&cpuset_rwsem
);
2819 set_bit(CS_ONLINE
, &cs
->flags
);
2820 if (is_spread_page(parent
))
2821 set_bit(CS_SPREAD_PAGE
, &cs
->flags
);
2822 if (is_spread_slab(parent
))
2823 set_bit(CS_SPREAD_SLAB
, &cs
->flags
);
2827 spin_lock_irq(&callback_lock
);
2828 if (is_in_v2_mode()) {
2829 cpumask_copy(cs
->effective_cpus
, parent
->effective_cpus
);
2830 cs
->effective_mems
= parent
->effective_mems
;
2831 cs
->use_parent_ecpus
= true;
2832 parent
->child_ecpus_count
++;
2834 spin_unlock_irq(&callback_lock
);
2836 if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN
, &css
->cgroup
->flags
))
2840 * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
2841 * set. This flag handling is implemented in cgroup core for
2842 * histrical reasons - the flag may be specified during mount.
2844 * Currently, if any sibling cpusets have exclusive cpus or mem, we
2845 * refuse to clone the configuration - thereby refusing the task to
2846 * be entered, and as a result refusing the sys_unshare() or
2847 * clone() which initiated it. If this becomes a problem for some
2848 * users who wish to allow that scenario, then this could be
2849 * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
2850 * (and likewise for mems) to the new cgroup.
2853 cpuset_for_each_child(tmp_cs
, pos_css
, parent
) {
2854 if (is_mem_exclusive(tmp_cs
) || is_cpu_exclusive(tmp_cs
)) {
2861 spin_lock_irq(&callback_lock
);
2862 cs
->mems_allowed
= parent
->mems_allowed
;
2863 cs
->effective_mems
= parent
->mems_allowed
;
2864 cpumask_copy(cs
->cpus_allowed
, parent
->cpus_allowed
);
2865 cpumask_copy(cs
->effective_cpus
, parent
->cpus_allowed
);
2866 spin_unlock_irq(&callback_lock
);
2868 percpu_up_write(&cpuset_rwsem
);
2874 * If the cpuset being removed has its flag 'sched_load_balance'
2875 * enabled, then simulate turning sched_load_balance off, which
2876 * will call rebuild_sched_domains_locked(). That is not needed
2877 * in the default hierarchy where only changes in partition
2878 * will cause repartitioning.
2880 * If the cpuset has the 'sched.partition' flag enabled, simulate
2881 * turning 'sched.partition" off.
2884 static void cpuset_css_offline(struct cgroup_subsys_state
*css
)
2886 struct cpuset
*cs
= css_cs(css
);
2889 percpu_down_write(&cpuset_rwsem
);
2891 if (is_partition_root(cs
))
2892 update_prstate(cs
, 0);
2894 if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys
) &&
2895 is_sched_load_balance(cs
))
2896 update_flag(CS_SCHED_LOAD_BALANCE
, cs
, 0);
2898 if (cs
->use_parent_ecpus
) {
2899 struct cpuset
*parent
= parent_cs(cs
);
2901 cs
->use_parent_ecpus
= false;
2902 parent
->child_ecpus_count
--;
2906 clear_bit(CS_ONLINE
, &cs
->flags
);
2908 percpu_up_write(&cpuset_rwsem
);
2912 static void cpuset_css_free(struct cgroup_subsys_state
*css
)
2914 struct cpuset
*cs
= css_cs(css
);
2919 static void cpuset_bind(struct cgroup_subsys_state
*root_css
)
2921 percpu_down_write(&cpuset_rwsem
);
2922 spin_lock_irq(&callback_lock
);
2924 if (is_in_v2_mode()) {
2925 cpumask_copy(top_cpuset
.cpus_allowed
, cpu_possible_mask
);
2926 top_cpuset
.mems_allowed
= node_possible_map
;
2928 cpumask_copy(top_cpuset
.cpus_allowed
,
2929 top_cpuset
.effective_cpus
);
2930 top_cpuset
.mems_allowed
= top_cpuset
.effective_mems
;
2933 spin_unlock_irq(&callback_lock
);
2934 percpu_up_write(&cpuset_rwsem
);
2938 * Make sure the new task conform to the current state of its parent,
2939 * which could have been changed by cpuset just after it inherits the
2940 * state from the parent and before it sits on the cgroup's task list.
2942 static void cpuset_fork(struct task_struct
*task
)
2944 if (task_css_is_root(task
, cpuset_cgrp_id
))
2947 set_cpus_allowed_ptr(task
, current
->cpus_ptr
);
2948 task
->mems_allowed
= current
->mems_allowed
;
2951 struct cgroup_subsys cpuset_cgrp_subsys
= {
2952 .css_alloc
= cpuset_css_alloc
,
2953 .css_online
= cpuset_css_online
,
2954 .css_offline
= cpuset_css_offline
,
2955 .css_free
= cpuset_css_free
,
2956 .can_attach
= cpuset_can_attach
,
2957 .cancel_attach
= cpuset_cancel_attach
,
2958 .attach
= cpuset_attach
,
2959 .post_attach
= cpuset_post_attach
,
2960 .bind
= cpuset_bind
,
2961 .fork
= cpuset_fork
,
2962 .legacy_cftypes
= legacy_files
,
2963 .dfl_cftypes
= dfl_files
,
2969 * cpuset_init - initialize cpusets at system boot
2971 * Description: Initialize top_cpuset
2974 int __init
cpuset_init(void)
2976 BUG_ON(percpu_init_rwsem(&cpuset_rwsem
));
2978 BUG_ON(!alloc_cpumask_var(&top_cpuset
.cpus_allowed
, GFP_KERNEL
));
2979 BUG_ON(!alloc_cpumask_var(&top_cpuset
.effective_cpus
, GFP_KERNEL
));
2980 BUG_ON(!zalloc_cpumask_var(&top_cpuset
.subparts_cpus
, GFP_KERNEL
));
2982 cpumask_setall(top_cpuset
.cpus_allowed
);
2983 nodes_setall(top_cpuset
.mems_allowed
);
2984 cpumask_setall(top_cpuset
.effective_cpus
);
2985 nodes_setall(top_cpuset
.effective_mems
);
2987 fmeter_init(&top_cpuset
.fmeter
);
2988 set_bit(CS_SCHED_LOAD_BALANCE
, &top_cpuset
.flags
);
2989 top_cpuset
.relax_domain_level
= -1;
2991 BUG_ON(!alloc_cpumask_var(&cpus_attach
, GFP_KERNEL
));
2997 * If CPU and/or memory hotplug handlers, below, unplug any CPUs
2998 * or memory nodes, we need to walk over the cpuset hierarchy,
2999 * removing that CPU or node from all cpusets. If this removes the
3000 * last CPU or node from a cpuset, then move the tasks in the empty
3001 * cpuset to its next-highest non-empty parent.
3003 static void remove_tasks_in_empty_cpuset(struct cpuset
*cs
)
3005 struct cpuset
*parent
;
3008 * Find its next-highest non-empty parent, (top cpuset
3009 * has online cpus, so can't be empty).
3011 parent
= parent_cs(cs
);
3012 while (cpumask_empty(parent
->cpus_allowed
) ||
3013 nodes_empty(parent
->mems_allowed
))
3014 parent
= parent_cs(parent
);
3016 if (cgroup_transfer_tasks(parent
->css
.cgroup
, cs
->css
.cgroup
)) {
3017 pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
3018 pr_cont_cgroup_name(cs
->css
.cgroup
);
3024 hotplug_update_tasks_legacy(struct cpuset
*cs
,
3025 struct cpumask
*new_cpus
, nodemask_t
*new_mems
,
3026 bool cpus_updated
, bool mems_updated
)
3030 spin_lock_irq(&callback_lock
);
3031 cpumask_copy(cs
->cpus_allowed
, new_cpus
);
3032 cpumask_copy(cs
->effective_cpus
, new_cpus
);
3033 cs
->mems_allowed
= *new_mems
;
3034 cs
->effective_mems
= *new_mems
;
3035 spin_unlock_irq(&callback_lock
);
3038 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
3039 * as the tasks will be migratecd to an ancestor.
3041 if (cpus_updated
&& !cpumask_empty(cs
->cpus_allowed
))
3042 update_tasks_cpumask(cs
);
3043 if (mems_updated
&& !nodes_empty(cs
->mems_allowed
))
3044 update_tasks_nodemask(cs
);
3046 is_empty
= cpumask_empty(cs
->cpus_allowed
) ||
3047 nodes_empty(cs
->mems_allowed
);
3049 percpu_up_write(&cpuset_rwsem
);
3052 * Move tasks to the nearest ancestor with execution resources,
3053 * This is full cgroup operation which will also call back into
3054 * cpuset. Should be done outside any lock.
3057 remove_tasks_in_empty_cpuset(cs
);
3059 percpu_down_write(&cpuset_rwsem
);
3063 hotplug_update_tasks(struct cpuset
*cs
,
3064 struct cpumask
*new_cpus
, nodemask_t
*new_mems
,
3065 bool cpus_updated
, bool mems_updated
)
3067 if (cpumask_empty(new_cpus
))
3068 cpumask_copy(new_cpus
, parent_cs(cs
)->effective_cpus
);
3069 if (nodes_empty(*new_mems
))
3070 *new_mems
= parent_cs(cs
)->effective_mems
;
3072 spin_lock_irq(&callback_lock
);
3073 cpumask_copy(cs
->effective_cpus
, new_cpus
);
3074 cs
->effective_mems
= *new_mems
;
3075 spin_unlock_irq(&callback_lock
);
3078 update_tasks_cpumask(cs
);
3080 update_tasks_nodemask(cs
);
3083 static bool force_rebuild
;
3085 void cpuset_force_rebuild(void)
3087 force_rebuild
= true;
3091 * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
3092 * @cs: cpuset in interest
3093 * @tmp: the tmpmasks structure pointer
3095 * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
3096 * offline, update @cs accordingly. If @cs ends up with no CPU or memory,
3097 * all its tasks are moved to the nearest ancestor with both resources.
3099 static void cpuset_hotplug_update_tasks(struct cpuset
*cs
, struct tmpmasks
*tmp
)
3101 static cpumask_t new_cpus
;
3102 static nodemask_t new_mems
;
3105 struct cpuset
*parent
;
3107 wait_event(cpuset_attach_wq
, cs
->attach_in_progress
== 0);
3109 percpu_down_write(&cpuset_rwsem
);
3112 * We have raced with task attaching. We wait until attaching
3113 * is finished, so we won't attach a task to an empty cpuset.
3115 if (cs
->attach_in_progress
) {
3116 percpu_up_write(&cpuset_rwsem
);
3120 parent
= parent_cs(cs
);
3121 compute_effective_cpumask(&new_cpus
, cs
, parent
);
3122 nodes_and(new_mems
, cs
->mems_allowed
, parent
->effective_mems
);
3124 if (cs
->nr_subparts_cpus
)
3126 * Make sure that CPUs allocated to child partitions
3127 * do not show up in effective_cpus.
3129 cpumask_andnot(&new_cpus
, &new_cpus
, cs
->subparts_cpus
);
3131 if (!tmp
|| !cs
->partition_root_state
)
3135 * In the unlikely event that a partition root has empty
3136 * effective_cpus or its parent becomes erroneous, we have to
3137 * transition it to the erroneous state.
3139 if (is_partition_root(cs
) && (cpumask_empty(&new_cpus
) ||
3140 (parent
->partition_root_state
== PRS_ERROR
))) {
3141 if (cs
->nr_subparts_cpus
) {
3142 spin_lock_irq(&callback_lock
);
3143 cs
->nr_subparts_cpus
= 0;
3144 cpumask_clear(cs
->subparts_cpus
);
3145 spin_unlock_irq(&callback_lock
);
3146 compute_effective_cpumask(&new_cpus
, cs
, parent
);
3150 * If the effective_cpus is empty because the child
3151 * partitions take away all the CPUs, we can keep
3152 * the current partition and let the child partitions
3153 * fight for available CPUs.
3155 if ((parent
->partition_root_state
== PRS_ERROR
) ||
3156 cpumask_empty(&new_cpus
)) {
3159 update_parent_subparts_cpumask(cs
, partcmd_disable
,
3161 old_prs
= cs
->partition_root_state
;
3162 if (old_prs
!= PRS_ERROR
) {
3163 spin_lock_irq(&callback_lock
);
3164 cs
->partition_root_state
= PRS_ERROR
;
3165 spin_unlock_irq(&callback_lock
);
3166 notify_partition_change(cs
, old_prs
, PRS_ERROR
);
3169 cpuset_force_rebuild();
3173 * On the other hand, an erroneous partition root may be transitioned
3174 * back to a regular one or a partition root with no CPU allocated
3175 * from the parent may change to erroneous.
3177 if (is_partition_root(parent
) &&
3178 ((cs
->partition_root_state
== PRS_ERROR
) ||
3179 !cpumask_intersects(&new_cpus
, parent
->subparts_cpus
)) &&
3180 update_parent_subparts_cpumask(cs
, partcmd_update
, NULL
, tmp
))
3181 cpuset_force_rebuild();
3184 cpus_updated
= !cpumask_equal(&new_cpus
, cs
->effective_cpus
);
3185 mems_updated
= !nodes_equal(new_mems
, cs
->effective_mems
);
3187 if (is_in_v2_mode())
3188 hotplug_update_tasks(cs
, &new_cpus
, &new_mems
,
3189 cpus_updated
, mems_updated
);
3191 hotplug_update_tasks_legacy(cs
, &new_cpus
, &new_mems
,
3192 cpus_updated
, mems_updated
);
3194 percpu_up_write(&cpuset_rwsem
);
3198 * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
3200 * This function is called after either CPU or memory configuration has
3201 * changed and updates cpuset accordingly. The top_cpuset is always
3202 * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
3203 * order to make cpusets transparent (of no affect) on systems that are
3204 * actively using CPU hotplug but making no active use of cpusets.
3206 * Non-root cpusets are only affected by offlining. If any CPUs or memory
3207 * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
3210 * Note that CPU offlining during suspend is ignored. We don't modify
3211 * cpusets across suspend/resume cycles at all.
3213 static void cpuset_hotplug_workfn(struct work_struct
*work
)
3215 static cpumask_t new_cpus
;
3216 static nodemask_t new_mems
;
3217 bool cpus_updated
, mems_updated
;
3218 bool on_dfl
= is_in_v2_mode();
3219 struct tmpmasks tmp
, *ptmp
= NULL
;
3221 if (on_dfl
&& !alloc_cpumasks(NULL
, &tmp
))
3224 percpu_down_write(&cpuset_rwsem
);
3226 /* fetch the available cpus/mems and find out which changed how */
3227 cpumask_copy(&new_cpus
, cpu_active_mask
);
3228 new_mems
= node_states
[N_MEMORY
];
3231 * If subparts_cpus is populated, it is likely that the check below
3232 * will produce a false positive on cpus_updated when the cpu list
3233 * isn't changed. It is extra work, but it is better to be safe.
3235 cpus_updated
= !cpumask_equal(top_cpuset
.effective_cpus
, &new_cpus
);
3236 mems_updated
= !nodes_equal(top_cpuset
.effective_mems
, new_mems
);
3239 * In the rare case that hotplug removes all the cpus in subparts_cpus,
3240 * we assumed that cpus are updated.
3242 if (!cpus_updated
&& top_cpuset
.nr_subparts_cpus
)
3243 cpus_updated
= true;
3245 /* synchronize cpus_allowed to cpu_active_mask */
3247 spin_lock_irq(&callback_lock
);
3249 cpumask_copy(top_cpuset
.cpus_allowed
, &new_cpus
);
3251 * Make sure that CPUs allocated to child partitions
3252 * do not show up in effective_cpus. If no CPU is left,
3253 * we clear the subparts_cpus & let the child partitions
3254 * fight for the CPUs again.
3256 if (top_cpuset
.nr_subparts_cpus
) {
3257 if (cpumask_subset(&new_cpus
,
3258 top_cpuset
.subparts_cpus
)) {
3259 top_cpuset
.nr_subparts_cpus
= 0;
3260 cpumask_clear(top_cpuset
.subparts_cpus
);
3262 cpumask_andnot(&new_cpus
, &new_cpus
,
3263 top_cpuset
.subparts_cpus
);
3266 cpumask_copy(top_cpuset
.effective_cpus
, &new_cpus
);
3267 spin_unlock_irq(&callback_lock
);
3268 /* we don't mess with cpumasks of tasks in top_cpuset */
3271 /* synchronize mems_allowed to N_MEMORY */
3273 spin_lock_irq(&callback_lock
);
3275 top_cpuset
.mems_allowed
= new_mems
;
3276 top_cpuset
.effective_mems
= new_mems
;
3277 spin_unlock_irq(&callback_lock
);
3278 update_tasks_nodemask(&top_cpuset
);
3281 percpu_up_write(&cpuset_rwsem
);
3283 /* if cpus or mems changed, we need to propagate to descendants */
3284 if (cpus_updated
|| mems_updated
) {
3286 struct cgroup_subsys_state
*pos_css
;
3289 cpuset_for_each_descendant_pre(cs
, pos_css
, &top_cpuset
) {
3290 if (cs
== &top_cpuset
|| !css_tryget_online(&cs
->css
))
3294 cpuset_hotplug_update_tasks(cs
, ptmp
);
3302 /* rebuild sched domains if cpus_allowed has changed */
3303 if (cpus_updated
|| force_rebuild
) {
3304 force_rebuild
= false;
3305 rebuild_sched_domains();
3308 free_cpumasks(NULL
, ptmp
);
3311 void cpuset_update_active_cpus(void)
3314 * We're inside cpu hotplug critical region which usually nests
3315 * inside cgroup synchronization. Bounce actual hotplug processing
3316 * to a work item to avoid reverse locking order.
3318 schedule_work(&cpuset_hotplug_work
);
3321 void cpuset_wait_for_hotplug(void)
3323 flush_work(&cpuset_hotplug_work
);
3327 * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
3328 * Call this routine anytime after node_states[N_MEMORY] changes.
3329 * See cpuset_update_active_cpus() for CPU hotplug handling.
3331 static int cpuset_track_online_nodes(struct notifier_block
*self
,
3332 unsigned long action
, void *arg
)
3334 schedule_work(&cpuset_hotplug_work
);
3338 static struct notifier_block cpuset_track_online_nodes_nb
= {
3339 .notifier_call
= cpuset_track_online_nodes
,
3340 .priority
= 10, /* ??! */
3344 * cpuset_init_smp - initialize cpus_allowed
3346 * Description: Finish top cpuset after cpu, node maps are initialized
3348 void __init
cpuset_init_smp(void)
3350 cpumask_copy(top_cpuset
.cpus_allowed
, cpu_active_mask
);
3351 top_cpuset
.mems_allowed
= node_states
[N_MEMORY
];
3352 top_cpuset
.old_mems_allowed
= top_cpuset
.mems_allowed
;
3354 cpumask_copy(top_cpuset
.effective_cpus
, cpu_active_mask
);
3355 top_cpuset
.effective_mems
= node_states
[N_MEMORY
];
3357 register_hotmemory_notifier(&cpuset_track_online_nodes_nb
);
3359 cpuset_migrate_mm_wq
= alloc_ordered_workqueue("cpuset_migrate_mm", 0);
3360 BUG_ON(!cpuset_migrate_mm_wq
);
3364 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
3365 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
3366 * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
3368 * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
3369 * attached to the specified @tsk. Guaranteed to return some non-empty
3370 * subset of cpu_online_mask, even if this means going outside the
3374 void cpuset_cpus_allowed(struct task_struct
*tsk
, struct cpumask
*pmask
)
3376 unsigned long flags
;
3378 spin_lock_irqsave(&callback_lock
, flags
);
3379 guarantee_online_cpus(tsk
, pmask
);
3380 spin_unlock_irqrestore(&callback_lock
, flags
);
3384 * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
3385 * @tsk: pointer to task_struct with which the scheduler is struggling
3387 * Description: In the case that the scheduler cannot find an allowed cpu in
3388 * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
3389 * mode however, this value is the same as task_cs(tsk)->effective_cpus,
3390 * which will not contain a sane cpumask during cases such as cpu hotplugging.
3391 * This is the absolute last resort for the scheduler and it is only used if
3392 * _every_ other avenue has been traveled.
3394 * Returns true if the affinity of @tsk was changed, false otherwise.
3397 bool cpuset_cpus_allowed_fallback(struct task_struct
*tsk
)
3399 const struct cpumask
*possible_mask
= task_cpu_possible_mask(tsk
);
3400 const struct cpumask
*cs_mask
;
3401 bool changed
= false;
3404 cs_mask
= task_cs(tsk
)->cpus_allowed
;
3405 if (is_in_v2_mode() && cpumask_subset(cs_mask
, possible_mask
)) {
3406 do_set_cpus_allowed(tsk
, cs_mask
);
3412 * We own tsk->cpus_allowed, nobody can change it under us.
3414 * But we used cs && cs->cpus_allowed lockless and thus can
3415 * race with cgroup_attach_task() or update_cpumask() and get
3416 * the wrong tsk->cpus_allowed. However, both cases imply the
3417 * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
3418 * which takes task_rq_lock().
3420 * If we are called after it dropped the lock we must see all
3421 * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
3422 * set any mask even if it is not right from task_cs() pov,
3423 * the pending set_cpus_allowed_ptr() will fix things.
3425 * select_fallback_rq() will fix things ups and set cpu_possible_mask
3431 void __init
cpuset_init_current_mems_allowed(void)
3433 nodes_setall(current
->mems_allowed
);
3437 * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
3438 * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
3440 * Description: Returns the nodemask_t mems_allowed of the cpuset
3441 * attached to the specified @tsk. Guaranteed to return some non-empty
3442 * subset of node_states[N_MEMORY], even if this means going outside the
3446 nodemask_t
cpuset_mems_allowed(struct task_struct
*tsk
)
3449 unsigned long flags
;
3451 spin_lock_irqsave(&callback_lock
, flags
);
3453 guarantee_online_mems(task_cs(tsk
), &mask
);
3455 spin_unlock_irqrestore(&callback_lock
, flags
);
3461 * cpuset_nodemask_valid_mems_allowed - check nodemask vs. current mems_allowed
3462 * @nodemask: the nodemask to be checked
3464 * Are any of the nodes in the nodemask allowed in current->mems_allowed?
3466 int cpuset_nodemask_valid_mems_allowed(nodemask_t
*nodemask
)
3468 return nodes_intersects(*nodemask
, current
->mems_allowed
);
3472 * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
3473 * mem_hardwall ancestor to the specified cpuset. Call holding
3474 * callback_lock. If no ancestor is mem_exclusive or mem_hardwall
3475 * (an unusual configuration), then returns the root cpuset.
3477 static struct cpuset
*nearest_hardwall_ancestor(struct cpuset
*cs
)
3479 while (!(is_mem_exclusive(cs
) || is_mem_hardwall(cs
)) && parent_cs(cs
))
3485 * cpuset_node_allowed - Can we allocate on a memory node?
3486 * @node: is this an allowed node?
3487 * @gfp_mask: memory allocation flags
3489 * If we're in interrupt, yes, we can always allocate. If @node is set in
3490 * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this
3491 * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
3492 * yes. If current has access to memory reserves as an oom victim, yes.
3495 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
3496 * and do not allow allocations outside the current tasks cpuset
3497 * unless the task has been OOM killed.
3498 * GFP_KERNEL allocations are not so marked, so can escape to the
3499 * nearest enclosing hardwalled ancestor cpuset.
3501 * Scanning up parent cpusets requires callback_lock. The
3502 * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
3503 * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
3504 * current tasks mems_allowed came up empty on the first pass over
3505 * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
3506 * cpuset are short of memory, might require taking the callback_lock.
3508 * The first call here from mm/page_alloc:get_page_from_freelist()
3509 * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
3510 * so no allocation on a node outside the cpuset is allowed (unless
3511 * in interrupt, of course).
3513 * The second pass through get_page_from_freelist() doesn't even call
3514 * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
3515 * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
3516 * in alloc_flags. That logic and the checks below have the combined
3518 * in_interrupt - any node ok (current task context irrelevant)
3519 * GFP_ATOMIC - any node ok
3520 * tsk_is_oom_victim - any node ok
3521 * GFP_KERNEL - any node in enclosing hardwalled cpuset ok
3522 * GFP_USER - only nodes in current tasks mems allowed ok.
3524 bool __cpuset_node_allowed(int node
, gfp_t gfp_mask
)
3526 struct cpuset
*cs
; /* current cpuset ancestors */
3527 int allowed
; /* is allocation in zone z allowed? */
3528 unsigned long flags
;
3532 if (node_isset(node
, current
->mems_allowed
))
3535 * Allow tasks that have access to memory reserves because they have
3536 * been OOM killed to get memory anywhere.
3538 if (unlikely(tsk_is_oom_victim(current
)))
3540 if (gfp_mask
& __GFP_HARDWALL
) /* If hardwall request, stop here */
3543 if (current
->flags
& PF_EXITING
) /* Let dying task have memory */
3546 /* Not hardwall and node outside mems_allowed: scan up cpusets */
3547 spin_lock_irqsave(&callback_lock
, flags
);
3550 cs
= nearest_hardwall_ancestor(task_cs(current
));
3551 allowed
= node_isset(node
, cs
->mems_allowed
);
3554 spin_unlock_irqrestore(&callback_lock
, flags
);
3559 * cpuset_mem_spread_node() - On which node to begin search for a file page
3560 * cpuset_slab_spread_node() - On which node to begin search for a slab page
3562 * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
3563 * tasks in a cpuset with is_spread_page or is_spread_slab set),
3564 * and if the memory allocation used cpuset_mem_spread_node()
3565 * to determine on which node to start looking, as it will for
3566 * certain page cache or slab cache pages such as used for file
3567 * system buffers and inode caches, then instead of starting on the
3568 * local node to look for a free page, rather spread the starting
3569 * node around the tasks mems_allowed nodes.
3571 * We don't have to worry about the returned node being offline
3572 * because "it can't happen", and even if it did, it would be ok.
3574 * The routines calling guarantee_online_mems() are careful to
3575 * only set nodes in task->mems_allowed that are online. So it
3576 * should not be possible for the following code to return an
3577 * offline node. But if it did, that would be ok, as this routine
3578 * is not returning the node where the allocation must be, only
3579 * the node where the search should start. The zonelist passed to
3580 * __alloc_pages() will include all nodes. If the slab allocator
3581 * is passed an offline node, it will fall back to the local node.
3582 * See kmem_cache_alloc_node().
3585 static int cpuset_spread_node(int *rotor
)
3587 return *rotor
= next_node_in(*rotor
, current
->mems_allowed
);
3590 int cpuset_mem_spread_node(void)
3592 if (current
->cpuset_mem_spread_rotor
== NUMA_NO_NODE
)
3593 current
->cpuset_mem_spread_rotor
=
3594 node_random(¤t
->mems_allowed
);
3596 return cpuset_spread_node(¤t
->cpuset_mem_spread_rotor
);
3599 int cpuset_slab_spread_node(void)
3601 if (current
->cpuset_slab_spread_rotor
== NUMA_NO_NODE
)
3602 current
->cpuset_slab_spread_rotor
=
3603 node_random(¤t
->mems_allowed
);
3605 return cpuset_spread_node(¤t
->cpuset_slab_spread_rotor
);
3608 EXPORT_SYMBOL_GPL(cpuset_mem_spread_node
);
3611 * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
3612 * @tsk1: pointer to task_struct of some task.
3613 * @tsk2: pointer to task_struct of some other task.
3615 * Description: Return true if @tsk1's mems_allowed intersects the
3616 * mems_allowed of @tsk2. Used by the OOM killer to determine if
3617 * one of the task's memory usage might impact the memory available
3621 int cpuset_mems_allowed_intersects(const struct task_struct
*tsk1
,
3622 const struct task_struct
*tsk2
)
3624 return nodes_intersects(tsk1
->mems_allowed
, tsk2
->mems_allowed
);
3628 * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
3630 * Description: Prints current's name, cpuset name, and cached copy of its
3631 * mems_allowed to the kernel log.
3633 void cpuset_print_current_mems_allowed(void)
3635 struct cgroup
*cgrp
;
3639 cgrp
= task_cs(current
)->css
.cgroup
;
3640 pr_cont(",cpuset=");
3641 pr_cont_cgroup_name(cgrp
);
3642 pr_cont(",mems_allowed=%*pbl",
3643 nodemask_pr_args(¤t
->mems_allowed
));
3649 * Collection of memory_pressure is suppressed unless
3650 * this flag is enabled by writing "1" to the special
3651 * cpuset file 'memory_pressure_enabled' in the root cpuset.
3654 int cpuset_memory_pressure_enabled __read_mostly
;
3657 * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
3659 * Keep a running average of the rate of synchronous (direct)
3660 * page reclaim efforts initiated by tasks in each cpuset.
3662 * This represents the rate at which some task in the cpuset
3663 * ran low on memory on all nodes it was allowed to use, and
3664 * had to enter the kernels page reclaim code in an effort to
3665 * create more free memory by tossing clean pages or swapping
3666 * or writing dirty pages.
3668 * Display to user space in the per-cpuset read-only file
3669 * "memory_pressure". Value displayed is an integer
3670 * representing the recent rate of entry into the synchronous
3671 * (direct) page reclaim by any task attached to the cpuset.
3674 void __cpuset_memory_pressure_bump(void)
3677 fmeter_markevent(&task_cs(current
)->fmeter
);
3681 #ifdef CONFIG_PROC_PID_CPUSET
3683 * proc_cpuset_show()
3684 * - Print tasks cpuset path into seq_file.
3685 * - Used for /proc/<pid>/cpuset.
3686 * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
3687 * doesn't really matter if tsk->cpuset changes after we read it,
3688 * and we take cpuset_rwsem, keeping cpuset_attach() from changing it
3691 int proc_cpuset_show(struct seq_file
*m
, struct pid_namespace
*ns
,
3692 struct pid
*pid
, struct task_struct
*tsk
)
3695 struct cgroup_subsys_state
*css
;
3699 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
3703 css
= task_get_css(tsk
, cpuset_cgrp_id
);
3704 retval
= cgroup_path_ns(css
->cgroup
, buf
, PATH_MAX
,
3705 current
->nsproxy
->cgroup_ns
);
3707 if (retval
>= PATH_MAX
)
3708 retval
= -ENAMETOOLONG
;
3719 #endif /* CONFIG_PROC_PID_CPUSET */
3721 /* Display task mems_allowed in /proc/<pid>/status file. */
3722 void cpuset_task_status_allowed(struct seq_file
*m
, struct task_struct
*task
)
3724 seq_printf(m
, "Mems_allowed:\t%*pb\n",
3725 nodemask_pr_args(&task
->mems_allowed
));
3726 seq_printf(m
, "Mems_allowed_list:\t%*pbl\n",
3727 nodemask_pr_args(&task
->mems_allowed
));