Branch data Line data Source code
1 : : /*
2 : : * kernel/cpuset.c
3 : : *
4 : : * Processor and Memory placement constraints for sets of tasks.
5 : : *
6 : : * Copyright (C) 2003 BULL SA.
7 : : * Copyright (C) 2004-2007 Silicon Graphics, Inc.
8 : : * Copyright (C) 2006 Google, Inc
9 : : *
10 : : * Portions derived from Patrick Mochel's sysfs code.
11 : : * sysfs is Copyright (c) 2001-3 Patrick Mochel
12 : : *
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
18 : : * by Max Krasnyansky
19 : : *
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.
23 : : */
24 : :
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>
31 : : #include <linux/fs.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>
38 : : #include <linux/mm.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>
68 : :
69 : : DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
70 : : DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
71 : :
72 : : /* See "Frequency meter" comments, below. */
73 : :
74 : : struct fmeter {
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 */
79 : : };
80 : :
81 : : struct cpuset {
82 : : struct cgroup_subsys_state css;
83 : :
84 : : unsigned long flags; /* "unsigned long" so bitops work */
85 : :
86 : : /*
87 : : * On default hierarchy:
88 : : *
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
91 : : * parent masks.
92 : : *
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.
96 : : *
97 : : * effective_mask == configured_mask & parent's effective_mask,
98 : : * and if it ends up empty, it will inherit the parent's mask.
99 : : *
100 : : *
101 : : * On legacy hierachy:
102 : : *
103 : : * The user-configured masks are always the same with effective masks.
104 : : */
105 : :
106 : : /* user-configured CPUs and Memory Nodes allow to tasks */
107 : : cpumask_var_t cpus_allowed;
108 : : nodemask_t mems_allowed;
109 : :
110 : : /* effective CPUs and Memory Nodes allow to tasks */
111 : : cpumask_var_t effective_cpus;
112 : : nodemask_t effective_mems;
113 : :
114 : : /*
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.
118 : : *
119 : : * effective_cpus contains only onlined CPUs, but subparts_cpus
120 : : * may have offlined ones.
121 : : */
122 : : cpumask_var_t subparts_cpus;
123 : :
124 : : /*
125 : : * This is old Memory Nodes tasks took on.
126 : : *
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.
133 : : */
134 : : nodemask_t old_mems_allowed;
135 : :
136 : : struct fmeter fmeter; /* memory_pressure filter */
137 : :
138 : : /*
139 : : * Tasks are being attached to this cpuset. Used to prevent
140 : : * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
141 : : */
142 : : int attach_in_progress;
143 : :
144 : : /* partition number for rebuild_sched_domains() */
145 : : int pn;
146 : :
147 : : /* for custom sched domain */
148 : : int relax_domain_level;
149 : :
150 : : /* number of CPUs in subparts_cpus */
151 : : int nr_subparts_cpus;
152 : :
153 : : /* partition root state */
154 : : int partition_root_state;
155 : :
156 : : /*
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
160 : : */
161 : : int use_parent_ecpus;
162 : : int child_ecpus_count;
163 : : };
164 : :
165 : : /*
166 : : * Partition root states:
167 : : *
168 : : * 0 - not a partition root
169 : : *
170 : : * 1 - partition root
171 : : *
172 : : * -1 - invalid partition root
173 : : * None of the cpus in cpus_allowed can be put into the parent's
174 : : * subparts_cpus. In this case, the cpuset is not a real partition
175 : : * root anymore. However, the CPU_EXCLUSIVE bit will still be set
176 : : * and the cpuset can be restored back to a partition root if the
177 : : * parent cpuset can give more CPUs back to this child cpuset.
178 : : */
179 : : #define PRS_DISABLED 0
180 : : #define PRS_ENABLED 1
181 : : #define PRS_ERROR -1
182 : :
183 : : /*
184 : : * Temporary cpumasks for working with partitions that are passed among
185 : : * functions to avoid memory allocation in inner functions.
186 : : */
187 : : struct tmpmasks {
188 : : cpumask_var_t addmask, delmask; /* For partition root */
189 : : cpumask_var_t new_cpus; /* For update_cpumasks_hier() */
190 : : };
191 : :
192 : : static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
193 : : {
194 [ # # # # : 6868 : return css ? container_of(css, struct cpuset, css) : NULL;
# # # # #
# # # + -
# # # # #
# # # # #
# # # # #
# # # # #
+ - - + #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # ]
195 : : }
196 : :
197 : : /* Retrieve the cpuset for a task */
198 : : static inline struct cpuset *task_cs(struct task_struct *task)
199 : : {
200 : : return css_cs(task_css(task, cpuset_cgrp_id));
201 : : }
202 : :
203 : : static inline struct cpuset *parent_cs(struct cpuset *cs)
204 : : {
205 : 404 : return css_cs(cs->css.parent);
206 : : }
207 : :
208 : : /* bits in struct cpuset flags field */
209 : : typedef enum {
210 : : CS_ONLINE,
211 : : CS_CPU_EXCLUSIVE,
212 : : CS_MEM_EXCLUSIVE,
213 : : CS_MEM_HARDWALL,
214 : : CS_MEMORY_MIGRATE,
215 : : CS_SCHED_LOAD_BALANCE,
216 : : CS_SPREAD_PAGE,
217 : : CS_SPREAD_SLAB,
218 : : } cpuset_flagbits_t;
219 : :
220 : : /* convenient tests for these bits */
221 : : static inline bool is_cpuset_online(struct cpuset *cs)
222 : : {
223 [ # # # # : 0 : return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # ]
224 : : }
225 : :
226 : : static inline int is_cpu_exclusive(const struct cpuset *cs)
227 : : {
228 : : return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
229 : : }
230 : :
231 : : static inline int is_mem_exclusive(const struct cpuset *cs)
232 : : {
233 : : return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
234 : : }
235 : :
236 : : static inline int is_mem_hardwall(const struct cpuset *cs)
237 : : {
238 : : return test_bit(CS_MEM_HARDWALL, &cs->flags);
239 : : }
240 : :
241 : : static inline int is_sched_load_balance(const struct cpuset *cs)
242 : : {
243 : : return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
244 : : }
245 : :
246 : : static inline int is_memory_migrate(const struct cpuset *cs)
247 : : {
248 : : return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
249 : : }
250 : :
251 : : static inline int is_spread_page(const struct cpuset *cs)
252 : : {
253 : : return test_bit(CS_SPREAD_PAGE, &cs->flags);
254 : : }
255 : :
256 : : static inline int is_spread_slab(const struct cpuset *cs)
257 : : {
258 : : return test_bit(CS_SPREAD_SLAB, &cs->flags);
259 : : }
260 : :
261 : : static inline int is_partition_root(const struct cpuset *cs)
262 : : {
263 : 0 : return cs->partition_root_state > 0;
264 : : }
265 : :
266 : : static struct cpuset top_cpuset = {
267 : : .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
268 : : (1 << CS_MEM_EXCLUSIVE)),
269 : : .partition_root_state = PRS_ENABLED,
270 : : };
271 : :
272 : : /**
273 : : * cpuset_for_each_child - traverse online children of a cpuset
274 : : * @child_cs: loop cursor pointing to the current child
275 : : * @pos_css: used for iteration
276 : : * @parent_cs: target cpuset to walk children of
277 : : *
278 : : * Walk @child_cs through the online children of @parent_cs. Must be used
279 : : * with RCU read locked.
280 : : */
281 : : #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
282 : : css_for_each_child((pos_css), &(parent_cs)->css) \
283 : : if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
284 : :
285 : : /**
286 : : * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
287 : : * @des_cs: loop cursor pointing to the current descendant
288 : : * @pos_css: used for iteration
289 : : * @root_cs: target cpuset to walk ancestor of
290 : : *
291 : : * Walk @des_cs through the online descendants of @root_cs. Must be used
292 : : * with RCU read locked. The caller may modify @pos_css by calling
293 : : * css_rightmost_descendant() to skip subtree. @root_cs is included in the
294 : : * iteration and the first node to be visited.
295 : : */
296 : : #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
297 : : css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
298 : : if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
299 : :
300 : : /*
301 : : * There are two global locks guarding cpuset structures - cpuset_mutex and
302 : : * callback_lock. We also require taking task_lock() when dereferencing a
303 : : * task's cpuset pointer. See "The task_lock() exception", at the end of this
304 : : * comment.
305 : : *
306 : : * A task must hold both locks to modify cpusets. If a task holds
307 : : * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
308 : : * is the only task able to also acquire callback_lock and be able to
309 : : * modify cpusets. It can perform various checks on the cpuset structure
310 : : * first, knowing nothing will change. It can also allocate memory while
311 : : * just holding cpuset_mutex. While it is performing these checks, various
312 : : * callback routines can briefly acquire callback_lock to query cpusets.
313 : : * Once it is ready to make the changes, it takes callback_lock, blocking
314 : : * everyone else.
315 : : *
316 : : * Calls to the kernel memory allocator can not be made while holding
317 : : * callback_lock, as that would risk double tripping on callback_lock
318 : : * from one of the callbacks into the cpuset code from within
319 : : * __alloc_pages().
320 : : *
321 : : * If a task is only holding callback_lock, then it has read-only
322 : : * access to cpusets.
323 : : *
324 : : * Now, the task_struct fields mems_allowed and mempolicy may be changed
325 : : * by other task, we use alloc_lock in the task_struct fields to protect
326 : : * them.
327 : : *
328 : : * The cpuset_common_file_read() handlers only hold callback_lock across
329 : : * small pieces of code, such as when reading out possibly multi-word
330 : : * cpumasks and nodemasks.
331 : : *
332 : : * Accessing a task's cpuset should be done in accordance with the
333 : : * guidelines for accessing subsystem state in kernel/cgroup.c
334 : : */
335 : :
336 : : DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem);
337 : :
338 : 41064 : void cpuset_read_lock(void)
339 : : {
340 : 41064 : percpu_down_read(&cpuset_rwsem);
341 : 41068 : }
342 : :
343 : 41068 : void cpuset_read_unlock(void)
344 : : {
345 : 41068 : percpu_up_read(&cpuset_rwsem);
346 : 41066 : }
347 : :
348 : : static DEFINE_SPINLOCK(callback_lock);
349 : :
350 : : static struct workqueue_struct *cpuset_migrate_mm_wq;
351 : :
352 : : /*
353 : : * CPU / memory hotplug is handled asynchronously.
354 : : */
355 : : static void cpuset_hotplug_workfn(struct work_struct *work);
356 : : static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
357 : :
358 : : static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
359 : :
360 : : /*
361 : : * Cgroup v2 behavior is used when on default hierarchy or the
362 : : * cgroup_v2_mode flag is set.
363 : : */
364 : 6868 : static inline bool is_in_v2_mode(void)
365 : : {
366 [ + + + - ]: 7272 : return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
367 : 404 : (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
368 : : }
369 : :
370 : : /*
371 : : * Return in pmask the portion of a cpusets's cpus_allowed that
372 : : * are online. If none are online, walk up the cpuset hierarchy
373 : : * until we find one that does have some online cpus.
374 : : *
375 : : * One way or another, we guarantee to return some non-empty subset
376 : : * of cpu_online_mask.
377 : : *
378 : : * Call with callback_lock or cpuset_mutex held.
379 : : */
380 : 0 : static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
381 : : {
382 [ # # ]: 0 : while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
383 : : cs = parent_cs(cs);
384 [ # # ]: 0 : if (unlikely(!cs)) {
385 : : /*
386 : : * The top cpuset doesn't have any online cpu as a
387 : : * consequence of a race between cpuset_hotplug_work
388 : : * and cpu hotplug notifier. But we know the top
389 : : * cpuset's effective_cpus is on its way to to be
390 : : * identical to cpu_online_mask.
391 : : */
392 : : cpumask_copy(pmask, cpu_online_mask);
393 : 0 : return;
394 : : }
395 : : }
396 : : cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
397 : : }
398 : :
399 : : /*
400 : : * Return in *pmask the portion of a cpusets's mems_allowed that
401 : : * are online, with memory. If none are online with memory, walk
402 : : * up the cpuset hierarchy until we find one that does have some
403 : : * online mems. The top cpuset always has some mems online.
404 : : *
405 : : * One way or another, we guarantee to return some non-empty subset
406 : : * of node_states[N_MEMORY].
407 : : *
408 : : * Call with callback_lock or cpuset_mutex held.
409 : : */
410 : 0 : static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
411 : : {
412 [ # # ]: 0 : while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
413 : : cs = parent_cs(cs);
414 : : nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
415 : 0 : }
416 : :
417 : : /*
418 : : * update task's spread flag if cpuset's page/slab spread flag is set
419 : : *
420 : : * Call with callback_lock or cpuset_mutex held.
421 : : */
422 : 0 : static void cpuset_update_task_spread_flag(struct cpuset *cs,
423 : : struct task_struct *tsk)
424 : : {
425 [ # # ]: 0 : if (is_spread_page(cs))
426 : : task_set_spread_page(tsk);
427 : : else
428 : : task_clear_spread_page(tsk);
429 : :
430 [ # # ]: 0 : if (is_spread_slab(cs))
431 : : task_set_spread_slab(tsk);
432 : : else
433 : : task_clear_spread_slab(tsk);
434 : 0 : }
435 : :
436 : : /*
437 : : * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
438 : : *
439 : : * One cpuset is a subset of another if all its allowed CPUs and
440 : : * Memory Nodes are a subset of the other, and its exclusive flags
441 : : * are only set if the other's are set. Call holding cpuset_mutex.
442 : : */
443 : :
444 : 0 : static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
445 : : {
446 [ # # ]: 0 : return cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
447 [ # # ]: 0 : nodes_subset(p->mems_allowed, q->mems_allowed) &&
448 [ # # # # ]: 0 : is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
449 : : is_mem_exclusive(p) <= is_mem_exclusive(q);
450 : : }
451 : :
452 : : /**
453 : : * alloc_cpumasks - allocate three cpumasks for cpuset
454 : : * @cs: the cpuset that have cpumasks to be allocated.
455 : : * @tmp: the tmpmasks structure pointer
456 : : * Return: 0 if successful, -ENOMEM otherwise.
457 : : *
458 : : * Only one of the two input arguments should be non-NULL.
459 : : */
460 : 0 : static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
461 : : {
462 : : cpumask_var_t *pmask1, *pmask2, *pmask3;
463 : :
464 [ # # ]: 0 : if (cs) {
465 : 0 : pmask1 = &cs->cpus_allowed;
466 : 0 : pmask2 = &cs->effective_cpus;
467 : 0 : pmask3 = &cs->subparts_cpus;
468 : : } else {
469 : 0 : pmask1 = &tmp->new_cpus;
470 : 0 : pmask2 = &tmp->addmask;
471 : 0 : pmask3 = &tmp->delmask;
472 : : }
473 : :
474 : : if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))
475 : : return -ENOMEM;
476 : :
477 : : if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))
478 : : goto free_one;
479 : :
480 : : if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))
481 : : goto free_two;
482 : :
483 : : return 0;
484 : :
485 : : free_two:
486 : : free_cpumask_var(*pmask2);
487 : : free_one:
488 : : free_cpumask_var(*pmask1);
489 : : return -ENOMEM;
490 : : }
491 : :
492 : : /**
493 : : * free_cpumasks - free cpumasks in a tmpmasks structure
494 : : * @cs: the cpuset that have cpumasks to be free.
495 : : * @tmp: the tmpmasks structure pointer
496 : : */
497 : : static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
498 : : {
499 : : if (cs) {
500 : : free_cpumask_var(cs->cpus_allowed);
501 : : free_cpumask_var(cs->effective_cpus);
502 : : free_cpumask_var(cs->subparts_cpus);
503 : : }
504 : : if (tmp) {
505 : : free_cpumask_var(tmp->new_cpus);
506 : : free_cpumask_var(tmp->addmask);
507 : : free_cpumask_var(tmp->delmask);
508 : : }
509 : : }
510 : :
511 : : /**
512 : : * alloc_trial_cpuset - allocate a trial cpuset
513 : : * @cs: the cpuset that the trial cpuset duplicates
514 : : */
515 : 0 : static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
516 : : {
517 : : struct cpuset *trial;
518 : :
519 : 0 : trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
520 [ # # ]: 0 : if (!trial)
521 : : return NULL;
522 : :
523 [ # # ]: 0 : if (alloc_cpumasks(trial, NULL)) {
524 : 0 : kfree(trial);
525 : 0 : return NULL;
526 : : }
527 : :
528 : : cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
529 : : cpumask_copy(trial->effective_cpus, cs->effective_cpus);
530 : 0 : return trial;
531 : : }
532 : :
533 : : /**
534 : : * free_cpuset - free the cpuset
535 : : * @cs: the cpuset to be freed
536 : : */
537 : : static inline void free_cpuset(struct cpuset *cs)
538 : : {
539 : : free_cpumasks(cs, NULL);
540 : 0 : kfree(cs);
541 : : }
542 : :
543 : : /*
544 : : * validate_change() - Used to validate that any proposed cpuset change
545 : : * follows the structural rules for cpusets.
546 : : *
547 : : * If we replaced the flag and mask values of the current cpuset
548 : : * (cur) with those values in the trial cpuset (trial), would
549 : : * our various subset and exclusive rules still be valid? Presumes
550 : : * cpuset_mutex held.
551 : : *
552 : : * 'cur' is the address of an actual, in-use cpuset. Operations
553 : : * such as list traversal that depend on the actual address of the
554 : : * cpuset in the list must use cur below, not trial.
555 : : *
556 : : * 'trial' is the address of bulk structure copy of cur, with
557 : : * perhaps one or more of the fields cpus_allowed, mems_allowed,
558 : : * or flags changed to new, trial values.
559 : : *
560 : : * Return 0 if valid, -errno if not.
561 : : */
562 : :
563 : 0 : static int validate_change(struct cpuset *cur, struct cpuset *trial)
564 : : {
565 : : struct cgroup_subsys_state *css;
566 : : struct cpuset *c, *par;
567 : : int ret;
568 : :
569 : : rcu_read_lock();
570 : :
571 : : /* Each of our child cpusets must be a subset of us */
572 : : ret = -EBUSY;
573 [ # # # # ]: 0 : cpuset_for_each_child(c, css, cur)
574 [ # # ]: 0 : if (!is_cpuset_subset(c, trial))
575 : : goto out;
576 : :
577 : : /* Remaining checks don't apply to root cpuset */
578 : : ret = 0;
579 [ # # ]: 0 : if (cur == &top_cpuset)
580 : : goto out;
581 : :
582 : : par = parent_cs(cur);
583 : :
584 : : /* On legacy hiearchy, we must be a subset of our parent cpuset. */
585 : : ret = -EACCES;
586 [ # # # # ]: 0 : if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
587 : : goto out;
588 : :
589 : : /*
590 : : * If either I or some sibling (!= me) is exclusive, we can't
591 : : * overlap
592 : : */
593 : : ret = -EINVAL;
594 [ # # # # ]: 0 : cpuset_for_each_child(c, css, par) {
595 [ # # # # : 0 : if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
# # ]
596 [ # # ]: 0 : c != cur &&
597 : : cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
598 : : goto out;
599 [ # # # # : 0 : if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
# # ]
600 [ # # ]: 0 : c != cur &&
601 : : nodes_intersects(trial->mems_allowed, c->mems_allowed))
602 : : goto out;
603 : : }
604 : :
605 : : /*
606 : : * Cpusets with tasks - existing or newly being attached - can't
607 : : * be changed to have empty cpus_allowed or mems_allowed.
608 : : */
609 : : ret = -ENOSPC;
610 [ # # # # ]: 0 : if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
611 [ # # # # ]: 0 : if (!cpumask_empty(cur->cpus_allowed) &&
612 : : cpumask_empty(trial->cpus_allowed))
613 : : goto out;
614 [ # # # # ]: 0 : if (!nodes_empty(cur->mems_allowed) &&
615 : : nodes_empty(trial->mems_allowed))
616 : : goto out;
617 : : }
618 : :
619 : : /*
620 : : * We can't shrink if we won't have enough room for SCHED_DEADLINE
621 : : * tasks.
622 : : */
623 : : ret = -EBUSY;
624 [ # # # # ]: 0 : if (is_cpu_exclusive(cur) &&
625 : 0 : !cpuset_cpumask_can_shrink(cur->cpus_allowed,
626 : 0 : trial->cpus_allowed))
627 : : goto out;
628 : :
629 : : ret = 0;
630 : : out:
631 : : rcu_read_unlock();
632 : 0 : return ret;
633 : : }
634 : :
635 : : #ifdef CONFIG_SMP
636 : : /*
637 : : * Helper routine for generate_sched_domains().
638 : : * Do cpusets a, b have overlapping effective cpus_allowed masks?
639 : : */
640 : : static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
641 : : {
642 : : return cpumask_intersects(a->effective_cpus, b->effective_cpus);
643 : : }
644 : :
645 : : static void
646 : : update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
647 : : {
648 [ # # ]: 0 : if (dattr->relax_domain_level < c->relax_domain_level)
649 : 0 : dattr->relax_domain_level = c->relax_domain_level;
650 : : return;
651 : : }
652 : :
653 : 0 : static void update_domain_attr_tree(struct sched_domain_attr *dattr,
654 : : struct cpuset *root_cs)
655 : : {
656 : : struct cpuset *cp;
657 : : struct cgroup_subsys_state *pos_css;
658 : :
659 : : rcu_read_lock();
660 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
661 : : /* skip the whole subtree if @cp doesn't have any CPU */
662 [ # # ]: 0 : if (cpumask_empty(cp->cpus_allowed)) {
663 : 0 : pos_css = css_rightmost_descendant(pos_css);
664 : 0 : continue;
665 : : }
666 : :
667 [ # # ]: 0 : if (is_sched_load_balance(cp))
668 : : update_domain_attr(dattr, cp);
669 : : }
670 : : rcu_read_unlock();
671 : 0 : }
672 : :
673 : : /* Must be called with cpuset_mutex held. */
674 : : static inline int nr_cpusets(void)
675 : : {
676 : : /* jump label reference count + the top-level cpuset */
677 : 0 : return static_key_count(&cpusets_enabled_key.key) + 1;
678 : : }
679 : :
680 : : /*
681 : : * generate_sched_domains()
682 : : *
683 : : * This function builds a partial partition of the systems CPUs
684 : : * A 'partial partition' is a set of non-overlapping subsets whose
685 : : * union is a subset of that set.
686 : : * The output of this function needs to be passed to kernel/sched/core.c
687 : : * partition_sched_domains() routine, which will rebuild the scheduler's
688 : : * load balancing domains (sched domains) as specified by that partial
689 : : * partition.
690 : : *
691 : : * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst
692 : : * for a background explanation of this.
693 : : *
694 : : * Does not return errors, on the theory that the callers of this
695 : : * routine would rather not worry about failures to rebuild sched
696 : : * domains when operating in the severe memory shortage situations
697 : : * that could cause allocation failures below.
698 : : *
699 : : * Must be called with cpuset_mutex held.
700 : : *
701 : : * The three key local variables below are:
702 : : * cp - cpuset pointer, used (together with pos_css) to perform a
703 : : * top-down scan of all cpusets. For our purposes, rebuilding
704 : : * the schedulers sched domains, we can ignore !is_sched_load_
705 : : * balance cpusets.
706 : : * csa - (for CpuSet Array) Array of pointers to all the cpusets
707 : : * that need to be load balanced, for convenient iterative
708 : : * access by the subsequent code that finds the best partition,
709 : : * i.e the set of domains (subsets) of CPUs such that the
710 : : * cpus_allowed of every cpuset marked is_sched_load_balance
711 : : * is a subset of one of these domains, while there are as
712 : : * many such domains as possible, each as small as possible.
713 : : * doms - Conversion of 'csa' to an array of cpumasks, for passing to
714 : : * the kernel/sched/core.c routine partition_sched_domains() in a
715 : : * convenient format, that can be easily compared to the prior
716 : : * value to determine what partition elements (sched domains)
717 : : * were changed (added or removed.)
718 : : *
719 : : * Finding the best partition (set of domains):
720 : : * The triple nested loops below over i, j, k scan over the
721 : : * load balanced cpusets (using the array of cpuset pointers in
722 : : * csa[]) looking for pairs of cpusets that have overlapping
723 : : * cpus_allowed, but which don't have the same 'pn' partition
724 : : * number and gives them in the same partition number. It keeps
725 : : * looping on the 'restart' label until it can no longer find
726 : : * any such pairs.
727 : : *
728 : : * The union of the cpus_allowed masks from the set of
729 : : * all cpusets having the same 'pn' value then form the one
730 : : * element of the partition (one sched domain) to be passed to
731 : : * partition_sched_domains().
732 : : */
733 : 0 : static int generate_sched_domains(cpumask_var_t **domains,
734 : : struct sched_domain_attr **attributes)
735 : : {
736 : : struct cpuset *cp; /* top-down scan of cpusets */
737 : : struct cpuset **csa; /* array of all cpuset ptrs */
738 : : int csn; /* how many cpuset ptrs in csa so far */
739 : : int i, j, k; /* indices for partition finding loops */
740 : : cpumask_var_t *doms; /* resulting partition; i.e. sched domains */
741 : : struct sched_domain_attr *dattr; /* attributes for custom domains */
742 : : int ndoms = 0; /* number of sched domains in result */
743 : : int nslot; /* next empty doms[] struct cpumask slot */
744 : : struct cgroup_subsys_state *pos_css;
745 : 0 : bool root_load_balance = is_sched_load_balance(&top_cpuset);
746 : :
747 : : doms = NULL;
748 : : dattr = NULL;
749 : : csa = NULL;
750 : :
751 : : /* Special case for the 99% of systems with one, full, sched domain */
752 [ # # # # ]: 0 : if (root_load_balance && !top_cpuset.nr_subparts_cpus) {
753 : : ndoms = 1;
754 : 0 : doms = alloc_sched_domains(ndoms);
755 [ # # ]: 0 : if (!doms)
756 : : goto done;
757 : :
758 : : dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
759 [ # # ]: 0 : if (dattr) {
760 : 0 : *dattr = SD_ATTR_INIT;
761 : 0 : update_domain_attr_tree(dattr, &top_cpuset);
762 : : }
763 : 0 : cpumask_and(doms[0], top_cpuset.effective_cpus,
764 : : housekeeping_cpumask(HK_FLAG_DOMAIN));
765 : :
766 : : goto done;
767 : : }
768 : :
769 : 0 : csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL);
770 [ # # ]: 0 : if (!csa)
771 : : goto done;
772 : : csn = 0;
773 : :
774 : : rcu_read_lock();
775 [ # # ]: 0 : if (root_load_balance)
776 : 0 : csa[csn++] = &top_cpuset;
777 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
778 [ # # ]: 0 : if (cp == &top_cpuset)
779 : 0 : continue;
780 : : /*
781 : : * Continue traversing beyond @cp iff @cp has some CPUs and
782 : : * isn't load balancing. The former is obvious. The
783 : : * latter: All child cpusets contain a subset of the
784 : : * parent's cpus, so just skip them, and then we call
785 : : * update_domain_attr_tree() to calc relax_domain_level of
786 : : * the corresponding sched domain.
787 : : *
788 : : * If root is load-balancing, we can skip @cp if it
789 : : * is a subset of the root's effective_cpus.
790 : : */
791 [ # # # # ]: 0 : if (!cpumask_empty(cp->cpus_allowed) &&
792 [ # # ]: 0 : !(is_sched_load_balance(cp) &&
793 : 0 : cpumask_intersects(cp->cpus_allowed,
794 : : housekeeping_cpumask(HK_FLAG_DOMAIN))))
795 : 0 : continue;
796 : :
797 [ # # # # ]: 0 : if (root_load_balance &&
798 : : cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus))
799 : 0 : continue;
800 : :
801 [ # # # # ]: 0 : if (is_sched_load_balance(cp) &&
802 : : !cpumask_empty(cp->effective_cpus))
803 : 0 : csa[csn++] = cp;
804 : :
805 : : /* skip @cp's subtree if not a partition root */
806 [ # # ]: 0 : if (!is_partition_root(cp))
807 : 0 : pos_css = css_rightmost_descendant(pos_css);
808 : : }
809 : : rcu_read_unlock();
810 : :
811 [ # # ]: 0 : for (i = 0; i < csn; i++)
812 : 0 : csa[i]->pn = i;
813 : 0 : ndoms = csn;
814 : :
815 : : restart:
816 : : /* Find the best partition (set of sched domains) */
817 [ # # ]: 0 : for (i = 0; i < csn; i++) {
818 : 0 : struct cpuset *a = csa[i];
819 : 0 : int apn = a->pn;
820 : :
821 [ # # ]: 0 : for (j = 0; j < csn; j++) {
822 : 0 : struct cpuset *b = csa[j];
823 : 0 : int bpn = b->pn;
824 : :
825 [ # # # # ]: 0 : if (apn != bpn && cpusets_overlap(a, b)) {
826 [ # # ]: 0 : for (k = 0; k < csn; k++) {
827 : 0 : struct cpuset *c = csa[k];
828 : :
829 [ # # ]: 0 : if (c->pn == bpn)
830 : 0 : c->pn = apn;
831 : : }
832 : 0 : ndoms--; /* one less element */
833 : 0 : goto restart;
834 : : }
835 : : }
836 : : }
837 : :
838 : : /*
839 : : * Now we know how many domains to create.
840 : : * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
841 : : */
842 : 0 : doms = alloc_sched_domains(ndoms);
843 [ # # ]: 0 : if (!doms)
844 : : goto done;
845 : :
846 : : /*
847 : : * The rest of the code, including the scheduler, can deal with
848 : : * dattr==NULL case. No need to abort if alloc fails.
849 : : */
850 : 0 : dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr),
851 : : GFP_KERNEL);
852 : :
853 [ # # ]: 0 : for (nslot = 0, i = 0; i < csn; i++) {
854 : 0 : struct cpuset *a = csa[i];
855 : : struct cpumask *dp;
856 : 0 : int apn = a->pn;
857 : :
858 [ # # ]: 0 : if (apn < 0) {
859 : : /* Skip completed partitions */
860 : 0 : continue;
861 : : }
862 : :
863 : 0 : dp = doms[nslot];
864 : :
865 [ # # ]: 0 : if (nslot == ndoms) {
866 : : static int warnings = 10;
867 [ # # ]: 0 : if (warnings) {
868 : 0 : pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
869 : : nslot, ndoms, csn, i, apn);
870 : 0 : warnings--;
871 : : }
872 : 0 : continue;
873 : : }
874 : :
875 : : cpumask_clear(dp);
876 [ # # ]: 0 : if (dattr)
877 : 0 : *(dattr + nslot) = SD_ATTR_INIT;
878 [ # # ]: 0 : for (j = i; j < csn; j++) {
879 : 0 : struct cpuset *b = csa[j];
880 : :
881 [ # # ]: 0 : if (apn == b->pn) {
882 : : cpumask_or(dp, dp, b->effective_cpus);
883 : 0 : cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
884 [ # # ]: 0 : if (dattr)
885 : 0 : update_domain_attr_tree(dattr + nslot, b);
886 : :
887 : : /* Done with this partition */
888 : 0 : b->pn = -1;
889 : : }
890 : : }
891 : 0 : nslot++;
892 : : }
893 [ # # ]: 0 : BUG_ON(nslot != ndoms);
894 : :
895 : : done:
896 : 0 : kfree(csa);
897 : :
898 : : /*
899 : : * Fallback to the default domain if kmalloc() failed.
900 : : * See comments in partition_sched_domains().
901 : : */
902 [ # # ]: 0 : if (doms == NULL)
903 : : ndoms = 1;
904 : :
905 : 0 : *domains = doms;
906 : 0 : *attributes = dattr;
907 : 0 : return ndoms;
908 : : }
909 : :
910 : 0 : static void update_tasks_root_domain(struct cpuset *cs)
911 : : {
912 : : struct css_task_iter it;
913 : : struct task_struct *task;
914 : :
915 : 0 : css_task_iter_start(&cs->css, 0, &it);
916 : :
917 [ # # ]: 0 : while ((task = css_task_iter_next(&it)))
918 : 0 : dl_add_task_root_domain(task);
919 : :
920 : 0 : css_task_iter_end(&it);
921 : 0 : }
922 : :
923 : 0 : static void rebuild_root_domains(void)
924 : : {
925 : : struct cpuset *cs = NULL;
926 : : struct cgroup_subsys_state *pos_css;
927 : :
928 : : percpu_rwsem_assert_held(&cpuset_rwsem);
929 : : lockdep_assert_cpus_held();
930 : : lockdep_assert_held(&sched_domains_mutex);
931 : :
932 : 0 : cgroup_enable_task_cg_lists();
933 : :
934 : : rcu_read_lock();
935 : :
936 : : /*
937 : : * Clear default root domain DL accounting, it will be computed again
938 : : * if a task belongs to it.
939 : : */
940 : 0 : dl_clear_root_domain(&def_root_domain);
941 : :
942 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
943 : :
944 [ # # ]: 0 : if (cpumask_empty(cs->effective_cpus)) {
945 : 0 : pos_css = css_rightmost_descendant(pos_css);
946 : 0 : continue;
947 : : }
948 : :
949 : : css_get(&cs->css);
950 : :
951 : : rcu_read_unlock();
952 : :
953 : 0 : update_tasks_root_domain(cs);
954 : :
955 : : rcu_read_lock();
956 : : css_put(&cs->css);
957 : : }
958 : : rcu_read_unlock();
959 : 0 : }
960 : :
961 : : static void
962 : 0 : partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
963 : : struct sched_domain_attr *dattr_new)
964 : : {
965 : 0 : mutex_lock(&sched_domains_mutex);
966 : 0 : partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
967 : 0 : rebuild_root_domains();
968 : 0 : mutex_unlock(&sched_domains_mutex);
969 : 0 : }
970 : :
971 : : /*
972 : : * Rebuild scheduler domains.
973 : : *
974 : : * If the flag 'sched_load_balance' of any cpuset with non-empty
975 : : * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
976 : : * which has that flag enabled, or if any cpuset with a non-empty
977 : : * 'cpus' is removed, then call this routine to rebuild the
978 : : * scheduler's dynamic sched domains.
979 : : *
980 : : * Call with cpuset_mutex held. Takes get_online_cpus().
981 : : */
982 : 0 : static void rebuild_sched_domains_locked(void)
983 : : {
984 : : struct sched_domain_attr *attr;
985 : : cpumask_var_t *doms;
986 : : int ndoms;
987 : :
988 : : lockdep_assert_cpus_held();
989 : : percpu_rwsem_assert_held(&cpuset_rwsem);
990 : :
991 : : /*
992 : : * We have raced with CPU hotplug. Don't do anything to avoid
993 : : * passing doms with offlined cpu to partition_sched_domains().
994 : : * Anyways, hotplug work item will rebuild sched domains.
995 : : */
996 [ # # # # ]: 0 : if (!top_cpuset.nr_subparts_cpus &&
997 : : !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
998 : 0 : return;
999 : :
1000 [ # # # # ]: 0 : if (top_cpuset.nr_subparts_cpus &&
1001 : : !cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask))
1002 : : return;
1003 : :
1004 : : /* Generate domain masks and attrs */
1005 : 0 : ndoms = generate_sched_domains(&doms, &attr);
1006 : :
1007 : : /* Have scheduler rebuild the domains */
1008 : 0 : partition_and_rebuild_sched_domains(ndoms, doms, attr);
1009 : : }
1010 : : #else /* !CONFIG_SMP */
1011 : : static void rebuild_sched_domains_locked(void)
1012 : : {
1013 : : }
1014 : : #endif /* CONFIG_SMP */
1015 : :
1016 : 0 : void rebuild_sched_domains(void)
1017 : : {
1018 : : get_online_cpus();
1019 : 0 : percpu_down_write(&cpuset_rwsem);
1020 : 0 : rebuild_sched_domains_locked();
1021 : 0 : percpu_up_write(&cpuset_rwsem);
1022 : : put_online_cpus();
1023 : 0 : }
1024 : :
1025 : : /**
1026 : : * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
1027 : : * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
1028 : : *
1029 : : * Iterate through each task of @cs updating its cpus_allowed to the
1030 : : * effective cpuset's. As this function is called with cpuset_mutex held,
1031 : : * cpuset membership stays stable.
1032 : : */
1033 : 0 : static void update_tasks_cpumask(struct cpuset *cs)
1034 : : {
1035 : : struct css_task_iter it;
1036 : : struct task_struct *task;
1037 : :
1038 : 0 : css_task_iter_start(&cs->css, 0, &it);
1039 [ # # ]: 0 : while ((task = css_task_iter_next(&it)))
1040 : 0 : set_cpus_allowed_ptr(task, cs->effective_cpus);
1041 : 0 : css_task_iter_end(&it);
1042 : 0 : }
1043 : :
1044 : : /**
1045 : : * compute_effective_cpumask - Compute the effective cpumask of the cpuset
1046 : : * @new_cpus: the temp variable for the new effective_cpus mask
1047 : : * @cs: the cpuset the need to recompute the new effective_cpus mask
1048 : : * @parent: the parent cpuset
1049 : : *
1050 : : * If the parent has subpartition CPUs, include them in the list of
1051 : : * allowable CPUs in computing the new effective_cpus mask. Since offlined
1052 : : * CPUs are not removed from subparts_cpus, we have to use cpu_active_mask
1053 : : * to mask those out.
1054 : : */
1055 : 0 : static void compute_effective_cpumask(struct cpumask *new_cpus,
1056 : : struct cpuset *cs, struct cpuset *parent)
1057 : : {
1058 [ # # ]: 0 : if (parent->nr_subparts_cpus) {
1059 : : cpumask_or(new_cpus, parent->effective_cpus,
1060 : : parent->subparts_cpus);
1061 : : cpumask_and(new_cpus, new_cpus, cs->cpus_allowed);
1062 : : cpumask_and(new_cpus, new_cpus, cpu_active_mask);
1063 : : } else {
1064 : : cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
1065 : : }
1066 : 0 : }
1067 : :
1068 : : /*
1069 : : * Commands for update_parent_subparts_cpumask
1070 : : */
1071 : : enum subparts_cmd {
1072 : : partcmd_enable, /* Enable partition root */
1073 : : partcmd_disable, /* Disable partition root */
1074 : : partcmd_update, /* Update parent's subparts_cpus */
1075 : : };
1076 : :
1077 : : /**
1078 : : * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
1079 : : * @cpuset: The cpuset that requests change in partition root state
1080 : : * @cmd: Partition root state change command
1081 : : * @newmask: Optional new cpumask for partcmd_update
1082 : : * @tmp: Temporary addmask and delmask
1083 : : * Return: 0, 1 or an error code
1084 : : *
1085 : : * For partcmd_enable, the cpuset is being transformed from a non-partition
1086 : : * root to a partition root. The cpus_allowed mask of the given cpuset will
1087 : : * be put into parent's subparts_cpus and taken away from parent's
1088 : : * effective_cpus. The function will return 0 if all the CPUs listed in
1089 : : * cpus_allowed can be granted or an error code will be returned.
1090 : : *
1091 : : * For partcmd_disable, the cpuset is being transofrmed from a partition
1092 : : * root back to a non-partition root. any CPUs in cpus_allowed that are in
1093 : : * parent's subparts_cpus will be taken away from that cpumask and put back
1094 : : * into parent's effective_cpus. 0 should always be returned.
1095 : : *
1096 : : * For partcmd_update, if the optional newmask is specified, the cpu
1097 : : * list is to be changed from cpus_allowed to newmask. Otherwise,
1098 : : * cpus_allowed is assumed to remain the same. The cpuset should either
1099 : : * be a partition root or an invalid partition root. The partition root
1100 : : * state may change if newmask is NULL and none of the requested CPUs can
1101 : : * be granted by the parent. The function will return 1 if changes to
1102 : : * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
1103 : : * Error code should only be returned when newmask is non-NULL.
1104 : : *
1105 : : * The partcmd_enable and partcmd_disable commands are used by
1106 : : * update_prstate(). The partcmd_update command is used by
1107 : : * update_cpumasks_hier() with newmask NULL and update_cpumask() with
1108 : : * newmask set.
1109 : : *
1110 : : * The checking is more strict when enabling partition root than the
1111 : : * other two commands.
1112 : : *
1113 : : * Because of the implicit cpu exclusive nature of a partition root,
1114 : : * cpumask changes that violates the cpu exclusivity rule will not be
1115 : : * permitted when checked by validate_change(). The validate_change()
1116 : : * function will also prevent any changes to the cpu list if it is not
1117 : : * a superset of children's cpu lists.
1118 : : */
1119 : 0 : static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
1120 : : struct cpumask *newmask,
1121 : : struct tmpmasks *tmp)
1122 : : {
1123 : : struct cpuset *parent = parent_cs(cpuset);
1124 : : int adding; /* Moving cpus from effective_cpus to subparts_cpus */
1125 : : int deleting; /* Moving cpus from subparts_cpus to effective_cpus */
1126 : : bool part_error = false; /* Partition error? */
1127 : :
1128 : : percpu_rwsem_assert_held(&cpuset_rwsem);
1129 : :
1130 : : /*
1131 : : * The parent must be a partition root.
1132 : : * The new cpumask, if present, or the current cpus_allowed must
1133 : : * not be empty.
1134 : : */
1135 [ # # # # ]: 0 : if (!is_partition_root(parent) ||
1136 [ # # # # ]: 0 : (newmask && cpumask_empty(newmask)) ||
1137 [ # # ]: 0 : (!newmask && cpumask_empty(cpuset->cpus_allowed)))
1138 : : return -EINVAL;
1139 : :
1140 : : /*
1141 : : * Enabling/disabling partition root is not allowed if there are
1142 : : * online children.
1143 : : */
1144 [ # # # # ]: 0 : if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css))
1145 : : return -EBUSY;
1146 : :
1147 : : /*
1148 : : * Enabling partition root is not allowed if not all the CPUs
1149 : : * can be granted from parent's effective_cpus or at least one
1150 : : * CPU will be left after that.
1151 : : */
1152 [ # # # # ]: 0 : if ((cmd == partcmd_enable) &&
1153 [ # # ]: 0 : (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) ||
1154 : : cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus)))
1155 : : return -EINVAL;
1156 : :
1157 : : /*
1158 : : * A cpumask update cannot make parent's effective_cpus become empty.
1159 : : */
1160 : : adding = deleting = false;
1161 [ # # ]: 0 : if (cmd == partcmd_enable) {
1162 : : cpumask_copy(tmp->addmask, cpuset->cpus_allowed);
1163 : : adding = true;
1164 [ # # ]: 0 : } else if (cmd == partcmd_disable) {
1165 : : deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
1166 : : parent->subparts_cpus);
1167 [ # # ]: 0 : } else if (newmask) {
1168 : : /*
1169 : : * partcmd_update with newmask:
1170 : : *
1171 : : * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
1172 : : * addmask = newmask & parent->effective_cpus
1173 : : * & ~parent->subparts_cpus
1174 : : */
1175 : : cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask);
1176 : : deleting = cpumask_and(tmp->delmask, tmp->delmask,
1177 : : parent->subparts_cpus);
1178 : :
1179 : : cpumask_and(tmp->addmask, newmask, parent->effective_cpus);
1180 : : adding = cpumask_andnot(tmp->addmask, tmp->addmask,
1181 : : parent->subparts_cpus);
1182 : : /*
1183 : : * Return error if the new effective_cpus could become empty.
1184 : : */
1185 [ # # # # ]: 0 : if (adding &&
1186 : : cpumask_equal(parent->effective_cpus, tmp->addmask)) {
1187 [ # # ]: 0 : if (!deleting)
1188 : : return -EINVAL;
1189 : : /*
1190 : : * As some of the CPUs in subparts_cpus might have
1191 : : * been offlined, we need to compute the real delmask
1192 : : * to confirm that.
1193 : : */
1194 [ # # ]: 0 : if (!cpumask_and(tmp->addmask, tmp->delmask,
1195 : : cpu_active_mask))
1196 : : return -EINVAL;
1197 : : cpumask_copy(tmp->addmask, parent->effective_cpus);
1198 : : }
1199 : : } else {
1200 : : /*
1201 : : * partcmd_update w/o newmask:
1202 : : *
1203 : : * addmask = cpus_allowed & parent->effectiveb_cpus
1204 : : *
1205 : : * Note that parent's subparts_cpus may have been
1206 : : * pre-shrunk in case there is a change in the cpu list.
1207 : : * So no deletion is needed.
1208 : : */
1209 : : adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed,
1210 : : parent->effective_cpus);
1211 : : part_error = cpumask_equal(tmp->addmask,
1212 : : parent->effective_cpus);
1213 : : }
1214 : :
1215 [ # # ]: 0 : if (cmd == partcmd_update) {
1216 : 0 : int prev_prs = cpuset->partition_root_state;
1217 : :
1218 : : /*
1219 : : * Check for possible transition between PRS_ENABLED
1220 : : * and PRS_ERROR.
1221 : : */
1222 [ # # # ]: 0 : switch (cpuset->partition_root_state) {
1223 : : case PRS_ENABLED:
1224 [ # # ]: 0 : if (part_error)
1225 : 0 : cpuset->partition_root_state = PRS_ERROR;
1226 : : break;
1227 : : case PRS_ERROR:
1228 [ # # ]: 0 : if (!part_error)
1229 : 0 : cpuset->partition_root_state = PRS_ENABLED;
1230 : : break;
1231 : : }
1232 : : /*
1233 : : * Set part_error if previously in invalid state.
1234 : : */
1235 : 0 : part_error = (prev_prs == PRS_ERROR);
1236 : : }
1237 : :
1238 [ # # # # ]: 0 : if (!part_error && (cpuset->partition_root_state == PRS_ERROR))
1239 : : return 0; /* Nothing need to be done */
1240 : :
1241 [ # # ]: 0 : if (cpuset->partition_root_state == PRS_ERROR) {
1242 : : /*
1243 : : * Remove all its cpus from parent's subparts_cpus.
1244 : : */
1245 : : adding = false;
1246 : : deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
1247 : : parent->subparts_cpus);
1248 : : }
1249 : :
1250 [ # # ]: 0 : if (!adding && !deleting)
1251 : : return 0;
1252 : :
1253 : : /*
1254 : : * Change the parent's subparts_cpus.
1255 : : * Newly added CPUs will be removed from effective_cpus and
1256 : : * newly deleted ones will be added back to effective_cpus.
1257 : : */
1258 : : spin_lock_irq(&callback_lock);
1259 [ # # ]: 0 : if (adding) {
1260 : : cpumask_or(parent->subparts_cpus,
1261 : : parent->subparts_cpus, tmp->addmask);
1262 : : cpumask_andnot(parent->effective_cpus,
1263 : : parent->effective_cpus, tmp->addmask);
1264 : : }
1265 [ # # ]: 0 : if (deleting) {
1266 : : cpumask_andnot(parent->subparts_cpus,
1267 : : parent->subparts_cpus, tmp->delmask);
1268 : : /*
1269 : : * Some of the CPUs in subparts_cpus might have been offlined.
1270 : : */
1271 : : cpumask_and(tmp->delmask, tmp->delmask, cpu_active_mask);
1272 : : cpumask_or(parent->effective_cpus,
1273 : : parent->effective_cpus, tmp->delmask);
1274 : : }
1275 : :
1276 : 0 : parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
1277 : : spin_unlock_irq(&callback_lock);
1278 : :
1279 : 0 : return cmd == partcmd_update;
1280 : : }
1281 : :
1282 : : /*
1283 : : * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
1284 : : * @cs: the cpuset to consider
1285 : : * @tmp: temp variables for calculating effective_cpus & partition setup
1286 : : *
1287 : : * When congifured cpumask is changed, the effective cpumasks of this cpuset
1288 : : * and all its descendants need to be updated.
1289 : : *
1290 : : * On legacy hierachy, effective_cpus will be the same with cpu_allowed.
1291 : : *
1292 : : * Called with cpuset_mutex held
1293 : : */
1294 : 0 : static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
1295 : : {
1296 : : struct cpuset *cp;
1297 : : struct cgroup_subsys_state *pos_css;
1298 : : bool need_rebuild_sched_domains = false;
1299 : :
1300 : : rcu_read_lock();
1301 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cp, pos_css, cs) {
1302 : : struct cpuset *parent = parent_cs(cp);
1303 : :
1304 : 0 : compute_effective_cpumask(tmp->new_cpus, cp, parent);
1305 : :
1306 : : /*
1307 : : * If it becomes empty, inherit the effective mask of the
1308 : : * parent, which is guaranteed to have some CPUs.
1309 : : */
1310 [ # # # # ]: 0 : if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) {
1311 : : cpumask_copy(tmp->new_cpus, parent->effective_cpus);
1312 [ # # ]: 0 : if (!cp->use_parent_ecpus) {
1313 : 0 : cp->use_parent_ecpus = true;
1314 : 0 : parent->child_ecpus_count++;
1315 : : }
1316 [ # # ]: 0 : } else if (cp->use_parent_ecpus) {
1317 : 0 : cp->use_parent_ecpus = false;
1318 [ # # # # ]: 0 : WARN_ON_ONCE(!parent->child_ecpus_count);
1319 : 0 : parent->child_ecpus_count--;
1320 : : }
1321 : :
1322 : : /*
1323 : : * Skip the whole subtree if the cpumask remains the same
1324 : : * and has no partition root state.
1325 : : */
1326 [ # # # # ]: 0 : if (!cp->partition_root_state &&
1327 : : cpumask_equal(tmp->new_cpus, cp->effective_cpus)) {
1328 : 0 : pos_css = css_rightmost_descendant(pos_css);
1329 : 0 : continue;
1330 : : }
1331 : :
1332 : : /*
1333 : : * update_parent_subparts_cpumask() should have been called
1334 : : * for cs already in update_cpumask(). We should also call
1335 : : * update_tasks_cpumask() again for tasks in the parent
1336 : : * cpuset if the parent's subparts_cpus changes.
1337 : : */
1338 [ # # # # ]: 0 : if ((cp != cs) && cp->partition_root_state) {
1339 [ # # # # ]: 0 : switch (parent->partition_root_state) {
1340 : : case PRS_DISABLED:
1341 : : /*
1342 : : * If parent is not a partition root or an
1343 : : * invalid partition root, clear the state
1344 : : * state and the CS_CPU_EXCLUSIVE flag.
1345 : : */
1346 [ # # # # ]: 0 : WARN_ON_ONCE(cp->partition_root_state
1347 : : != PRS_ERROR);
1348 : 0 : cp->partition_root_state = 0;
1349 : :
1350 : : /*
1351 : : * clear_bit() is an atomic operation and
1352 : : * readers aren't interested in the state
1353 : : * of CS_CPU_EXCLUSIVE anyway. So we can
1354 : : * just update the flag without holding
1355 : : * the callback_lock.
1356 : : */
1357 : 0 : clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
1358 : 0 : break;
1359 : :
1360 : : case PRS_ENABLED:
1361 [ # # ]: 0 : if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
1362 : 0 : update_tasks_cpumask(parent);
1363 : : break;
1364 : :
1365 : : case PRS_ERROR:
1366 : : /*
1367 : : * When parent is invalid, it has to be too.
1368 : : */
1369 : 0 : cp->partition_root_state = PRS_ERROR;
1370 [ # # ]: 0 : if (cp->nr_subparts_cpus) {
1371 : 0 : cp->nr_subparts_cpus = 0;
1372 : : cpumask_clear(cp->subparts_cpus);
1373 : : }
1374 : : break;
1375 : : }
1376 : : }
1377 : :
1378 [ # # ]: 0 : if (!css_tryget_online(&cp->css))
1379 : 0 : continue;
1380 : : rcu_read_unlock();
1381 : :
1382 : : spin_lock_irq(&callback_lock);
1383 : :
1384 : : cpumask_copy(cp->effective_cpus, tmp->new_cpus);
1385 [ # # # # ]: 0 : if (cp->nr_subparts_cpus &&
1386 : 0 : (cp->partition_root_state != PRS_ENABLED)) {
1387 : 0 : cp->nr_subparts_cpus = 0;
1388 : : cpumask_clear(cp->subparts_cpus);
1389 [ # # ]: 0 : } else if (cp->nr_subparts_cpus) {
1390 : : /*
1391 : : * Make sure that effective_cpus & subparts_cpus
1392 : : * are mutually exclusive.
1393 : : *
1394 : : * In the unlikely event that effective_cpus
1395 : : * becomes empty. we clear cp->nr_subparts_cpus and
1396 : : * let its child partition roots to compete for
1397 : : * CPUs again.
1398 : : */
1399 : : cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
1400 : : cp->subparts_cpus);
1401 [ # # ]: 0 : if (cpumask_empty(cp->effective_cpus)) {
1402 : : cpumask_copy(cp->effective_cpus, tmp->new_cpus);
1403 : : cpumask_clear(cp->subparts_cpus);
1404 : 0 : cp->nr_subparts_cpus = 0;
1405 [ # # ]: 0 : } else if (!cpumask_subset(cp->subparts_cpus,
1406 : : tmp->new_cpus)) {
1407 : : cpumask_andnot(cp->subparts_cpus,
1408 : : cp->subparts_cpus, tmp->new_cpus);
1409 : : cp->nr_subparts_cpus
1410 : 0 : = cpumask_weight(cp->subparts_cpus);
1411 : : }
1412 : : }
1413 : : spin_unlock_irq(&callback_lock);
1414 : :
1415 [ # # # # : 0 : WARN_ON(!is_in_v2_mode() &&
# # ]
1416 : : !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
1417 : :
1418 : 0 : update_tasks_cpumask(cp);
1419 : :
1420 : : /*
1421 : : * On legacy hierarchy, if the effective cpumask of any non-
1422 : : * empty cpuset is changed, we need to rebuild sched domains.
1423 : : * On default hierarchy, the cpuset needs to be a partition
1424 : : * root as well.
1425 : : */
1426 [ # # # # ]: 0 : if (!cpumask_empty(cp->cpus_allowed) &&
1427 [ # # ]: 0 : is_sched_load_balance(cp) &&
1428 [ # # ]: 0 : (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
1429 : : is_partition_root(cp)))
1430 : : need_rebuild_sched_domains = true;
1431 : :
1432 : : rcu_read_lock();
1433 : : css_put(&cp->css);
1434 : : }
1435 : : rcu_read_unlock();
1436 : :
1437 [ # # ]: 0 : if (need_rebuild_sched_domains)
1438 : 0 : rebuild_sched_domains_locked();
1439 : 0 : }
1440 : :
1441 : : /**
1442 : : * update_sibling_cpumasks - Update siblings cpumasks
1443 : : * @parent: Parent cpuset
1444 : : * @cs: Current cpuset
1445 : : * @tmp: Temp variables
1446 : : */
1447 : 0 : static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
1448 : : struct tmpmasks *tmp)
1449 : : {
1450 : : struct cpuset *sibling;
1451 : : struct cgroup_subsys_state *pos_css;
1452 : :
1453 : : /*
1454 : : * Check all its siblings and call update_cpumasks_hier()
1455 : : * if their use_parent_ecpus flag is set in order for them
1456 : : * to use the right effective_cpus value.
1457 : : */
1458 : : rcu_read_lock();
1459 [ # # # # ]: 0 : cpuset_for_each_child(sibling, pos_css, parent) {
1460 [ # # ]: 0 : if (sibling == cs)
1461 : 0 : continue;
1462 [ # # ]: 0 : if (!sibling->use_parent_ecpus)
1463 : 0 : continue;
1464 : :
1465 : 0 : update_cpumasks_hier(sibling, tmp);
1466 : : }
1467 : : rcu_read_unlock();
1468 : 0 : }
1469 : :
1470 : : /**
1471 : : * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
1472 : : * @cs: the cpuset to consider
1473 : : * @trialcs: trial cpuset
1474 : : * @buf: buffer of cpu numbers written to this cpuset
1475 : : */
1476 : 0 : static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
1477 : : const char *buf)
1478 : : {
1479 : : int retval;
1480 : : struct tmpmasks tmp;
1481 : :
1482 : : /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
1483 [ # # ]: 0 : if (cs == &top_cpuset)
1484 : : return -EACCES;
1485 : :
1486 : : /*
1487 : : * An empty cpus_allowed is ok only if the cpuset has no tasks.
1488 : : * Since cpulist_parse() fails on an empty mask, we special case
1489 : : * that parsing. The validate_change() call ensures that cpusets
1490 : : * with tasks have cpus.
1491 : : */
1492 [ # # ]: 0 : if (!*buf) {
1493 : : cpumask_clear(trialcs->cpus_allowed);
1494 : : } else {
1495 : : retval = cpulist_parse(buf, trialcs->cpus_allowed);
1496 [ # # ]: 0 : if (retval < 0)
1497 : : return retval;
1498 : :
1499 [ # # ]: 0 : if (!cpumask_subset(trialcs->cpus_allowed,
1500 : : top_cpuset.cpus_allowed))
1501 : : return -EINVAL;
1502 : : }
1503 : :
1504 : : /* Nothing to do if the cpus didn't change */
1505 [ # # ]: 0 : if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
1506 : : return 0;
1507 : :
1508 : 0 : retval = validate_change(cs, trialcs);
1509 [ # # ]: 0 : if (retval < 0)
1510 : : return retval;
1511 : :
1512 : : #ifdef CONFIG_CPUMASK_OFFSTACK
1513 : : /*
1514 : : * Use the cpumasks in trialcs for tmpmasks when they are pointers
1515 : : * to allocated cpumasks.
1516 : : */
1517 : : tmp.addmask = trialcs->subparts_cpus;
1518 : : tmp.delmask = trialcs->effective_cpus;
1519 : : tmp.new_cpus = trialcs->cpus_allowed;
1520 : : #endif
1521 : :
1522 [ # # ]: 0 : if (cs->partition_root_state) {
1523 : : /* Cpumask of a partition root cannot be empty */
1524 [ # # ]: 0 : if (cpumask_empty(trialcs->cpus_allowed))
1525 : : return -EINVAL;
1526 [ # # ]: 0 : if (update_parent_subparts_cpumask(cs, partcmd_update,
1527 : 0 : trialcs->cpus_allowed, &tmp) < 0)
1528 : : return -EINVAL;
1529 : : }
1530 : :
1531 : : spin_lock_irq(&callback_lock);
1532 : : cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
1533 : :
1534 : : /*
1535 : : * Make sure that subparts_cpus is a subset of cpus_allowed.
1536 : : */
1537 [ # # ]: 0 : if (cs->nr_subparts_cpus) {
1538 : : cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
1539 : : cs->cpus_allowed);
1540 : 0 : cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
1541 : : }
1542 : : spin_unlock_irq(&callback_lock);
1543 : :
1544 : 0 : update_cpumasks_hier(cs, &tmp);
1545 : :
1546 [ # # ]: 0 : if (cs->partition_root_state) {
1547 : : struct cpuset *parent = parent_cs(cs);
1548 : :
1549 : : /*
1550 : : * For partition root, update the cpumasks of sibling
1551 : : * cpusets if they use parent's effective_cpus.
1552 : : */
1553 [ # # ]: 0 : if (parent->child_ecpus_count)
1554 : 0 : update_sibling_cpumasks(parent, cs, &tmp);
1555 : : }
1556 : : return 0;
1557 : : }
1558 : :
1559 : : /*
1560 : : * Migrate memory region from one set of nodes to another. This is
1561 : : * performed asynchronously as it can be called from process migration path
1562 : : * holding locks involved in process management. All mm migrations are
1563 : : * performed in the queued order and can be waited for by flushing
1564 : : * cpuset_migrate_mm_wq.
1565 : : */
1566 : :
1567 : : struct cpuset_migrate_mm_work {
1568 : : struct work_struct work;
1569 : : struct mm_struct *mm;
1570 : : nodemask_t from;
1571 : : nodemask_t to;
1572 : : };
1573 : :
1574 : 0 : static void cpuset_migrate_mm_workfn(struct work_struct *work)
1575 : : {
1576 : : struct cpuset_migrate_mm_work *mwork =
1577 : : container_of(work, struct cpuset_migrate_mm_work, work);
1578 : :
1579 : : /* on a wq worker, no need to worry about %current's mems_allowed */
1580 : : do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
1581 : 0 : mmput(mwork->mm);
1582 : 0 : kfree(mwork);
1583 : 0 : }
1584 : :
1585 : 0 : static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
1586 : : const nodemask_t *to)
1587 : : {
1588 : : struct cpuset_migrate_mm_work *mwork;
1589 : :
1590 : 0 : mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
1591 [ # # ]: 0 : if (mwork) {
1592 : 0 : mwork->mm = mm;
1593 : 0 : mwork->from = *from;
1594 : 0 : mwork->to = *to;
1595 : 0 : INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
1596 : 0 : queue_work(cpuset_migrate_mm_wq, &mwork->work);
1597 : : } else {
1598 : 0 : mmput(mm);
1599 : : }
1600 : 0 : }
1601 : :
1602 : 207744 : static void cpuset_post_attach(void)
1603 : : {
1604 : 207744 : flush_workqueue(cpuset_migrate_mm_wq);
1605 : 207744 : }
1606 : :
1607 : : /*
1608 : : * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
1609 : : * @tsk: the task to change
1610 : : * @newmems: new nodes that the task will be set
1611 : : *
1612 : : * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
1613 : : * and rebind an eventual tasks' mempolicy. If the task is allocating in
1614 : : * parallel, it might temporarily see an empty intersection, which results in
1615 : : * a seqlock check and retry before OOM or allocation failure.
1616 : : */
1617 : 0 : static void cpuset_change_task_nodemask(struct task_struct *tsk,
1618 : : nodemask_t *newmems)
1619 : : {
1620 : : task_lock(tsk);
1621 : :
1622 : 0 : local_irq_disable();
1623 : : write_seqcount_begin(&tsk->mems_allowed_seq);
1624 : :
1625 : : nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
1626 : : mpol_rebind_task(tsk, newmems);
1627 : 0 : tsk->mems_allowed = *newmems;
1628 : :
1629 : : write_seqcount_end(&tsk->mems_allowed_seq);
1630 : 0 : local_irq_enable();
1631 : :
1632 : : task_unlock(tsk);
1633 : 0 : }
1634 : :
1635 : : static void *cpuset_being_rebound;
1636 : :
1637 : : /**
1638 : : * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
1639 : : * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
1640 : : *
1641 : : * Iterate through each task of @cs updating its mems_allowed to the
1642 : : * effective cpuset's. As this function is called with cpuset_mutex held,
1643 : : * cpuset membership stays stable.
1644 : : */
1645 : 0 : static void update_tasks_nodemask(struct cpuset *cs)
1646 : : {
1647 : : static nodemask_t newmems; /* protected by cpuset_mutex */
1648 : : struct css_task_iter it;
1649 : : struct task_struct *task;
1650 : :
1651 : 0 : cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
1652 : :
1653 : 0 : guarantee_online_mems(cs, &newmems);
1654 : :
1655 : : /*
1656 : : * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
1657 : : * take while holding tasklist_lock. Forks can happen - the
1658 : : * mpol_dup() cpuset_being_rebound check will catch such forks,
1659 : : * and rebind their vma mempolicies too. Because we still hold
1660 : : * the global cpuset_mutex, we know that no other rebind effort
1661 : : * will be contending for the global variable cpuset_being_rebound.
1662 : : * It's ok if we rebind the same mm twice; mpol_rebind_mm()
1663 : : * is idempotent. Also migrate pages in each mm to new nodes.
1664 : : */
1665 : 0 : css_task_iter_start(&cs->css, 0, &it);
1666 [ # # ]: 0 : while ((task = css_task_iter_next(&it))) {
1667 : : struct mm_struct *mm;
1668 : : bool migrate;
1669 : :
1670 : 0 : cpuset_change_task_nodemask(task, &newmems);
1671 : :
1672 : 0 : mm = get_task_mm(task);
1673 [ # # ]: 0 : if (!mm)
1674 : 0 : continue;
1675 : :
1676 : : migrate = is_memory_migrate(cs);
1677 : :
1678 : : mpol_rebind_mm(mm, &cs->mems_allowed);
1679 [ # # ]: 0 : if (migrate)
1680 : 0 : cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
1681 : : else
1682 : 0 : mmput(mm);
1683 : : }
1684 : 0 : css_task_iter_end(&it);
1685 : :
1686 : : /*
1687 : : * All the tasks' nodemasks have been updated, update
1688 : : * cs->old_mems_allowed.
1689 : : */
1690 : 0 : cs->old_mems_allowed = newmems;
1691 : :
1692 : : /* We're done rebinding vmas to this cpuset's new mems_allowed. */
1693 : 0 : cpuset_being_rebound = NULL;
1694 : 0 : }
1695 : :
1696 : : /*
1697 : : * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
1698 : : * @cs: the cpuset to consider
1699 : : * @new_mems: a temp variable for calculating new effective_mems
1700 : : *
1701 : : * When configured nodemask is changed, the effective nodemasks of this cpuset
1702 : : * and all its descendants need to be updated.
1703 : : *
1704 : : * On legacy hiearchy, effective_mems will be the same with mems_allowed.
1705 : : *
1706 : : * Called with cpuset_mutex held
1707 : : */
1708 : 0 : static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
1709 : : {
1710 : : struct cpuset *cp;
1711 : : struct cgroup_subsys_state *pos_css;
1712 : :
1713 : : rcu_read_lock();
1714 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cp, pos_css, cs) {
1715 : : struct cpuset *parent = parent_cs(cp);
1716 : :
1717 : : nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
1718 : :
1719 : : /*
1720 : : * If it becomes empty, inherit the effective mask of the
1721 : : * parent, which is guaranteed to have some MEMs.
1722 : : */
1723 [ # # # # ]: 0 : if (is_in_v2_mode() && nodes_empty(*new_mems))
1724 : 0 : *new_mems = parent->effective_mems;
1725 : :
1726 : : /* Skip the whole subtree if the nodemask remains the same. */
1727 [ # # ]: 0 : if (nodes_equal(*new_mems, cp->effective_mems)) {
1728 : 0 : pos_css = css_rightmost_descendant(pos_css);
1729 : 0 : continue;
1730 : : }
1731 : :
1732 [ # # ]: 0 : if (!css_tryget_online(&cp->css))
1733 : 0 : continue;
1734 : : rcu_read_unlock();
1735 : :
1736 : : spin_lock_irq(&callback_lock);
1737 : 0 : cp->effective_mems = *new_mems;
1738 : : spin_unlock_irq(&callback_lock);
1739 : :
1740 [ # # # # : 0 : WARN_ON(!is_in_v2_mode() &&
# # ]
1741 : : !nodes_equal(cp->mems_allowed, cp->effective_mems));
1742 : :
1743 : 0 : update_tasks_nodemask(cp);
1744 : :
1745 : : rcu_read_lock();
1746 : : css_put(&cp->css);
1747 : : }
1748 : : rcu_read_unlock();
1749 : 0 : }
1750 : :
1751 : : /*
1752 : : * Handle user request to change the 'mems' memory placement
1753 : : * of a cpuset. Needs to validate the request, update the
1754 : : * cpusets mems_allowed, and for each task in the cpuset,
1755 : : * update mems_allowed and rebind task's mempolicy and any vma
1756 : : * mempolicies and if the cpuset is marked 'memory_migrate',
1757 : : * migrate the tasks pages to the new memory.
1758 : : *
1759 : : * Call with cpuset_mutex held. May take callback_lock during call.
1760 : : * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
1761 : : * lock each such tasks mm->mmap_sem, scan its vma's and rebind
1762 : : * their mempolicies to the cpusets new mems_allowed.
1763 : : */
1764 : 0 : static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
1765 : : const char *buf)
1766 : : {
1767 : : int retval;
1768 : :
1769 : : /*
1770 : : * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
1771 : : * it's read-only
1772 : : */
1773 [ # # ]: 0 : if (cs == &top_cpuset) {
1774 : : retval = -EACCES;
1775 : : goto done;
1776 : : }
1777 : :
1778 : : /*
1779 : : * An empty mems_allowed is ok iff there are no tasks in the cpuset.
1780 : : * Since nodelist_parse() fails on an empty mask, we special case
1781 : : * that parsing. The validate_change() call ensures that cpusets
1782 : : * with tasks have memory.
1783 : : */
1784 [ # # ]: 0 : if (!*buf) {
1785 : : nodes_clear(trialcs->mems_allowed);
1786 : : } else {
1787 : : retval = nodelist_parse(buf, trialcs->mems_allowed);
1788 [ # # ]: 0 : if (retval < 0)
1789 : : goto done;
1790 : :
1791 [ # # ]: 0 : if (!nodes_subset(trialcs->mems_allowed,
1792 : : top_cpuset.mems_allowed)) {
1793 : : retval = -EINVAL;
1794 : : goto done;
1795 : : }
1796 : : }
1797 : :
1798 [ # # ]: 0 : if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
1799 : : retval = 0; /* Too easy - nothing to do */
1800 : : goto done;
1801 : : }
1802 : 0 : retval = validate_change(cs, trialcs);
1803 [ # # ]: 0 : if (retval < 0)
1804 : : goto done;
1805 : :
1806 : : spin_lock_irq(&callback_lock);
1807 : 0 : cs->mems_allowed = trialcs->mems_allowed;
1808 : : spin_unlock_irq(&callback_lock);
1809 : :
1810 : : /* use trialcs->mems_allowed as a temp variable */
1811 : 0 : update_nodemasks_hier(cs, &trialcs->mems_allowed);
1812 : : done:
1813 : 0 : return retval;
1814 : : }
1815 : :
1816 : 0 : bool current_cpuset_is_being_rebound(void)
1817 : : {
1818 : : bool ret;
1819 : :
1820 : : rcu_read_lock();
1821 : 0 : ret = task_cs(current) == cpuset_being_rebound;
1822 : : rcu_read_unlock();
1823 : :
1824 : 0 : return ret;
1825 : : }
1826 : :
1827 : 0 : static int update_relax_domain_level(struct cpuset *cs, s64 val)
1828 : : {
1829 : : #ifdef CONFIG_SMP
1830 [ # # # # ]: 0 : if (val < -1 || val >= sched_domain_level_max)
1831 : : return -EINVAL;
1832 : : #endif
1833 : :
1834 [ # # ]: 0 : if (val != cs->relax_domain_level) {
1835 : 0 : cs->relax_domain_level = val;
1836 [ # # # # ]: 0 : if (!cpumask_empty(cs->cpus_allowed) &&
1837 : : is_sched_load_balance(cs))
1838 : 0 : rebuild_sched_domains_locked();
1839 : : }
1840 : :
1841 : : return 0;
1842 : : }
1843 : :
1844 : : /**
1845 : : * update_tasks_flags - update the spread flags of tasks in the cpuset.
1846 : : * @cs: the cpuset in which each task's spread flags needs to be changed
1847 : : *
1848 : : * Iterate through each task of @cs updating its spread flags. As this
1849 : : * function is called with cpuset_mutex held, cpuset membership stays
1850 : : * stable.
1851 : : */
1852 : 0 : static void update_tasks_flags(struct cpuset *cs)
1853 : : {
1854 : : struct css_task_iter it;
1855 : : struct task_struct *task;
1856 : :
1857 : 0 : css_task_iter_start(&cs->css, 0, &it);
1858 [ # # ]: 0 : while ((task = css_task_iter_next(&it)))
1859 : 0 : cpuset_update_task_spread_flag(cs, task);
1860 : 0 : css_task_iter_end(&it);
1861 : 0 : }
1862 : :
1863 : : /*
1864 : : * update_flag - read a 0 or a 1 in a file and update associated flag
1865 : : * bit: the bit to update (see cpuset_flagbits_t)
1866 : : * cs: the cpuset to update
1867 : : * turning_on: whether the flag is being set or cleared
1868 : : *
1869 : : * Call with cpuset_mutex held.
1870 : : */
1871 : :
1872 : 0 : static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
1873 : : int turning_on)
1874 : : {
1875 : : struct cpuset *trialcs;
1876 : : int balance_flag_changed;
1877 : : int spread_flag_changed;
1878 : : int err;
1879 : :
1880 : 0 : trialcs = alloc_trial_cpuset(cs);
1881 [ # # ]: 0 : if (!trialcs)
1882 : : return -ENOMEM;
1883 : :
1884 [ # # ]: 0 : if (turning_on)
1885 : 0 : set_bit(bit, &trialcs->flags);
1886 : : else
1887 : 0 : clear_bit(bit, &trialcs->flags);
1888 : :
1889 : 0 : err = validate_change(cs, trialcs);
1890 [ # # ]: 0 : if (err < 0)
1891 : : goto out;
1892 : :
1893 : : balance_flag_changed = (is_sched_load_balance(cs) !=
1894 : : is_sched_load_balance(trialcs));
1895 : :
1896 : : spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
1897 [ # # # # ]: 0 : || (is_spread_page(cs) != is_spread_page(trialcs)));
1898 : :
1899 : : spin_lock_irq(&callback_lock);
1900 : 0 : cs->flags = trialcs->flags;
1901 : : spin_unlock_irq(&callback_lock);
1902 : :
1903 [ # # # # ]: 0 : if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
1904 : 0 : rebuild_sched_domains_locked();
1905 : :
1906 [ # # ]: 0 : if (spread_flag_changed)
1907 : 0 : update_tasks_flags(cs);
1908 : : out:
1909 : : free_cpuset(trialcs);
1910 : 0 : return err;
1911 : : }
1912 : :
1913 : : /*
1914 : : * update_prstate - update partititon_root_state
1915 : : * cs: the cpuset to update
1916 : : * val: 0 - disabled, 1 - enabled
1917 : : *
1918 : : * Call with cpuset_mutex held.
1919 : : */
1920 : 0 : static int update_prstate(struct cpuset *cs, int val)
1921 : : {
1922 : : int err;
1923 : : struct cpuset *parent = parent_cs(cs);
1924 : : struct tmpmasks tmp;
1925 : :
1926 [ # # ]: 0 : if ((val != 0) && (val != 1))
1927 : : return -EINVAL;
1928 [ # # ]: 0 : if (val == cs->partition_root_state)
1929 : : return 0;
1930 : :
1931 : : /*
1932 : : * Cannot force a partial or invalid partition root to a full
1933 : : * partition root.
1934 : : */
1935 [ # # # # ]: 0 : if (val && cs->partition_root_state)
1936 : : return -EINVAL;
1937 : :
1938 [ # # ]: 0 : if (alloc_cpumasks(NULL, &tmp))
1939 : : return -ENOMEM;
1940 : :
1941 : : err = -EINVAL;
1942 [ # # ]: 0 : if (!cs->partition_root_state) {
1943 : : /*
1944 : : * Turning on partition root requires setting the
1945 : : * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
1946 : : * cannot be NULL.
1947 : : */
1948 [ # # ]: 0 : if (cpumask_empty(cs->cpus_allowed))
1949 : : goto out;
1950 : :
1951 : 0 : err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
1952 [ # # ]: 0 : if (err)
1953 : : goto out;
1954 : :
1955 : 0 : err = update_parent_subparts_cpumask(cs, partcmd_enable,
1956 : : NULL, &tmp);
1957 [ # # ]: 0 : if (err) {
1958 : 0 : update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1959 : 0 : goto out;
1960 : : }
1961 : 0 : cs->partition_root_state = PRS_ENABLED;
1962 : : } else {
1963 : : /*
1964 : : * Turning off partition root will clear the
1965 : : * CS_CPU_EXCLUSIVE bit.
1966 : : */
1967 [ # # ]: 0 : if (cs->partition_root_state == PRS_ERROR) {
1968 : 0 : cs->partition_root_state = 0;
1969 : 0 : update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1970 : : err = 0;
1971 : 0 : goto out;
1972 : : }
1973 : :
1974 : 0 : err = update_parent_subparts_cpumask(cs, partcmd_disable,
1975 : : NULL, &tmp);
1976 [ # # ]: 0 : if (err)
1977 : : goto out;
1978 : :
1979 : 0 : cs->partition_root_state = 0;
1980 : :
1981 : : /* Turning off CS_CPU_EXCLUSIVE will not return error */
1982 : 0 : update_flag(CS_CPU_EXCLUSIVE, cs, 0);
1983 : : }
1984 : :
1985 : : /*
1986 : : * Update cpumask of parent's tasks except when it is the top
1987 : : * cpuset as some system daemons cannot be mapped to other CPUs.
1988 : : */
1989 [ # # ]: 0 : if (parent != &top_cpuset)
1990 : 0 : update_tasks_cpumask(parent);
1991 : :
1992 [ # # ]: 0 : if (parent->child_ecpus_count)
1993 : 0 : update_sibling_cpumasks(parent, cs, &tmp);
1994 : :
1995 : 0 : rebuild_sched_domains_locked();
1996 : : out:
1997 : : free_cpumasks(NULL, &tmp);
1998 : 0 : return err;
1999 : : }
2000 : :
2001 : : /*
2002 : : * Frequency meter - How fast is some event occurring?
2003 : : *
2004 : : * These routines manage a digitally filtered, constant time based,
2005 : : * event frequency meter. There are four routines:
2006 : : * fmeter_init() - initialize a frequency meter.
2007 : : * fmeter_markevent() - called each time the event happens.
2008 : : * fmeter_getrate() - returns the recent rate of such events.
2009 : : * fmeter_update() - internal routine used to update fmeter.
2010 : : *
2011 : : * A common data structure is passed to each of these routines,
2012 : : * which is used to keep track of the state required to manage the
2013 : : * frequency meter and its digital filter.
2014 : : *
2015 : : * The filter works on the number of events marked per unit time.
2016 : : * The filter is single-pole low-pass recursive (IIR). The time unit
2017 : : * is 1 second. Arithmetic is done using 32-bit integers scaled to
2018 : : * simulate 3 decimal digits of precision (multiplied by 1000).
2019 : : *
2020 : : * With an FM_COEF of 933, and a time base of 1 second, the filter
2021 : : * has a half-life of 10 seconds, meaning that if the events quit
2022 : : * happening, then the rate returned from the fmeter_getrate()
2023 : : * will be cut in half each 10 seconds, until it converges to zero.
2024 : : *
2025 : : * It is not worth doing a real infinitely recursive filter. If more
2026 : : * than FM_MAXTICKS ticks have elapsed since the last filter event,
2027 : : * just compute FM_MAXTICKS ticks worth, by which point the level
2028 : : * will be stable.
2029 : : *
2030 : : * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
2031 : : * arithmetic overflow in the fmeter_update() routine.
2032 : : *
2033 : : * Given the simple 32 bit integer arithmetic used, this meter works
2034 : : * best for reporting rates between one per millisecond (msec) and
2035 : : * one per 32 (approx) seconds. At constant rates faster than one
2036 : : * per msec it maxes out at values just under 1,000,000. At constant
2037 : : * rates between one per msec, and one per second it will stabilize
2038 : : * to a value N*1000, where N is the rate of events per second.
2039 : : * At constant rates between one per second and one per 32 seconds,
2040 : : * it will be choppy, moving up on the seconds that have an event,
2041 : : * and then decaying until the next event. At rates slower than
2042 : : * about one in 32 seconds, it decays all the way back to zero between
2043 : : * each event.
2044 : : */
2045 : :
2046 : : #define FM_COEF 933 /* coefficient for half-life of 10 secs */
2047 : : #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */
2048 : : #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
2049 : : #define FM_SCALE 1000 /* faux fixed point scale */
2050 : :
2051 : : /* Initialize a frequency meter */
2052 : : static void fmeter_init(struct fmeter *fmp)
2053 : : {
2054 : 404 : fmp->cnt = 0;
2055 : 404 : fmp->val = 0;
2056 : 404 : fmp->time = 0;
2057 : 404 : spin_lock_init(&fmp->lock);
2058 : : }
2059 : :
2060 : : /* Internal meter update - process cnt events and update value */
2061 : 0 : static void fmeter_update(struct fmeter *fmp)
2062 : : {
2063 : : time64_t now;
2064 : : u32 ticks;
2065 : :
2066 : 0 : now = ktime_get_seconds();
2067 : 0 : ticks = now - fmp->time;
2068 : :
2069 [ # # ]: 0 : if (ticks == 0)
2070 : 0 : return;
2071 : :
2072 : 0 : ticks = min(FM_MAXTICKS, ticks);
2073 [ # # ]: 0 : while (ticks-- > 0)
2074 : 0 : fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
2075 : 0 : fmp->time = now;
2076 : :
2077 : 0 : fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
2078 : 0 : fmp->cnt = 0;
2079 : : }
2080 : :
2081 : : /* Process any previous ticks, then bump cnt by one (times scale). */
2082 : 0 : static void fmeter_markevent(struct fmeter *fmp)
2083 : : {
2084 : : spin_lock(&fmp->lock);
2085 : 0 : fmeter_update(fmp);
2086 : 0 : fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
2087 : : spin_unlock(&fmp->lock);
2088 : 0 : }
2089 : :
2090 : : /* Process any previous ticks, then return current value. */
2091 : 0 : static int fmeter_getrate(struct fmeter *fmp)
2092 : : {
2093 : : int val;
2094 : :
2095 : : spin_lock(&fmp->lock);
2096 : 0 : fmeter_update(fmp);
2097 : 0 : val = fmp->val;
2098 : : spin_unlock(&fmp->lock);
2099 : 0 : return val;
2100 : : }
2101 : :
2102 : : static struct cpuset *cpuset_attach_old_cs;
2103 : :
2104 : : /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
2105 : 0 : static int cpuset_can_attach(struct cgroup_taskset *tset)
2106 : : {
2107 : : struct cgroup_subsys_state *css;
2108 : : struct cpuset *cs;
2109 : : struct task_struct *task;
2110 : : int ret;
2111 : :
2112 : : /* used later by cpuset_attach() */
2113 : 0 : cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
2114 : 0 : cs = css_cs(css);
2115 : :
2116 : 0 : percpu_down_write(&cpuset_rwsem);
2117 : :
2118 : : /* allow moving tasks into an empty cpuset if on default hierarchy */
2119 : : ret = -ENOSPC;
2120 [ # # # # ]: 0 : if (!is_in_v2_mode() &&
2121 [ # # ]: 0 : (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
2122 : : goto out_unlock;
2123 : :
2124 [ # # ]: 0 : cgroup_taskset_for_each(task, css, tset) {
2125 : 0 : ret = task_can_attach(task, cs->cpus_allowed);
2126 [ # # ]: 0 : if (ret)
2127 : : goto out_unlock;
2128 : 0 : ret = security_task_setscheduler(task);
2129 [ # # ]: 0 : if (ret)
2130 : : goto out_unlock;
2131 : : }
2132 : :
2133 : : /*
2134 : : * Mark attach is in progress. This makes validate_change() fail
2135 : : * changes which zero cpus/mems_allowed.
2136 : : */
2137 : 0 : cs->attach_in_progress++;
2138 : : ret = 0;
2139 : : out_unlock:
2140 : 0 : percpu_up_write(&cpuset_rwsem);
2141 : 0 : return ret;
2142 : : }
2143 : :
2144 : 0 : static void cpuset_cancel_attach(struct cgroup_taskset *tset)
2145 : : {
2146 : : struct cgroup_subsys_state *css;
2147 : :
2148 : 0 : cgroup_taskset_first(tset, &css);
2149 : :
2150 : 0 : percpu_down_write(&cpuset_rwsem);
2151 : 0 : css_cs(css)->attach_in_progress--;
2152 : 0 : percpu_up_write(&cpuset_rwsem);
2153 : 0 : }
2154 : :
2155 : : /*
2156 : : * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach()
2157 : : * but we can't allocate it dynamically there. Define it global and
2158 : : * allocate from cpuset_init().
2159 : : */
2160 : : static cpumask_var_t cpus_attach;
2161 : :
2162 : 0 : static void cpuset_attach(struct cgroup_taskset *tset)
2163 : : {
2164 : : /* static buf protected by cpuset_mutex */
2165 : : static nodemask_t cpuset_attach_nodemask_to;
2166 : : struct task_struct *task;
2167 : : struct task_struct *leader;
2168 : : struct cgroup_subsys_state *css;
2169 : : struct cpuset *cs;
2170 : 0 : struct cpuset *oldcs = cpuset_attach_old_cs;
2171 : :
2172 : 0 : cgroup_taskset_first(tset, &css);
2173 : 0 : cs = css_cs(css);
2174 : :
2175 : 0 : percpu_down_write(&cpuset_rwsem);
2176 : :
2177 : : /* prepare for attach */
2178 [ # # ]: 0 : if (cs == &top_cpuset)
2179 : : cpumask_copy(cpus_attach, cpu_possible_mask);
2180 : : else
2181 : 0 : guarantee_online_cpus(cs, cpus_attach);
2182 : :
2183 : 0 : guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
2184 : :
2185 [ # # ]: 0 : cgroup_taskset_for_each(task, css, tset) {
2186 : : /*
2187 : : * can_attach beforehand should guarantee that this doesn't
2188 : : * fail. TODO: have a better way to handle failure here
2189 : : */
2190 [ # # # # ]: 0 : WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
2191 : :
2192 : 0 : cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
2193 : 0 : cpuset_update_task_spread_flag(cs, task);
2194 : : }
2195 : :
2196 : : /*
2197 : : * Change mm for all threadgroup leaders. This is expensive and may
2198 : : * sleep and should be moved outside migration path proper.
2199 : : */
2200 : 0 : cpuset_attach_nodemask_to = cs->effective_mems;
2201 [ # # # # ]: 0 : cgroup_taskset_for_each_leader(leader, css, tset) {
2202 : 0 : struct mm_struct *mm = get_task_mm(leader);
2203 : :
2204 [ # # ]: 0 : if (mm) {
2205 : : mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
2206 : :
2207 : : /*
2208 : : * old_mems_allowed is the same with mems_allowed
2209 : : * here, except if this task is being moved
2210 : : * automatically due to hotplug. In that case
2211 : : * @mems_allowed has been updated and is empty, so
2212 : : * @old_mems_allowed is the right nodesets that we
2213 : : * migrate mm from.
2214 : : */
2215 [ # # ]: 0 : if (is_memory_migrate(cs))
2216 : 0 : cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
2217 : : &cpuset_attach_nodemask_to);
2218 : : else
2219 : 0 : mmput(mm);
2220 : : }
2221 : : }
2222 : :
2223 : 0 : cs->old_mems_allowed = cpuset_attach_nodemask_to;
2224 : :
2225 : 0 : cs->attach_in_progress--;
2226 [ # # ]: 0 : if (!cs->attach_in_progress)
2227 : 0 : wake_up(&cpuset_attach_wq);
2228 : :
2229 : 0 : percpu_up_write(&cpuset_rwsem);
2230 : 0 : }
2231 : :
2232 : : /* The various types of files and directories in a cpuset file system */
2233 : :
2234 : : typedef enum {
2235 : : FILE_MEMORY_MIGRATE,
2236 : : FILE_CPULIST,
2237 : : FILE_MEMLIST,
2238 : : FILE_EFFECTIVE_CPULIST,
2239 : : FILE_EFFECTIVE_MEMLIST,
2240 : : FILE_SUBPARTS_CPULIST,
2241 : : FILE_CPU_EXCLUSIVE,
2242 : : FILE_MEM_EXCLUSIVE,
2243 : : FILE_MEM_HARDWALL,
2244 : : FILE_SCHED_LOAD_BALANCE,
2245 : : FILE_PARTITION_ROOT,
2246 : : FILE_SCHED_RELAX_DOMAIN_LEVEL,
2247 : : FILE_MEMORY_PRESSURE_ENABLED,
2248 : : FILE_MEMORY_PRESSURE,
2249 : : FILE_SPREAD_PAGE,
2250 : : FILE_SPREAD_SLAB,
2251 : : } cpuset_filetype_t;
2252 : :
2253 : 0 : static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
2254 : : u64 val)
2255 : : {
2256 : : struct cpuset *cs = css_cs(css);
2257 : 0 : cpuset_filetype_t type = cft->private;
2258 : : int retval = 0;
2259 : :
2260 : : get_online_cpus();
2261 : 0 : percpu_down_write(&cpuset_rwsem);
2262 [ # # ]: 0 : if (!is_cpuset_online(cs)) {
2263 : : retval = -ENODEV;
2264 : : goto out_unlock;
2265 : : }
2266 : :
2267 [ # # # # : 0 : switch (type) {
# # # #
# ]
2268 : : case FILE_CPU_EXCLUSIVE:
2269 : 0 : retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
2270 : 0 : break;
2271 : : case FILE_MEM_EXCLUSIVE:
2272 : 0 : retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
2273 : 0 : break;
2274 : : case FILE_MEM_HARDWALL:
2275 : 0 : retval = update_flag(CS_MEM_HARDWALL, cs, val);
2276 : 0 : break;
2277 : : case FILE_SCHED_LOAD_BALANCE:
2278 : 0 : retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
2279 : 0 : break;
2280 : : case FILE_MEMORY_MIGRATE:
2281 : 0 : retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
2282 : 0 : break;
2283 : : case FILE_MEMORY_PRESSURE_ENABLED:
2284 : 0 : cpuset_memory_pressure_enabled = !!val;
2285 : 0 : break;
2286 : : case FILE_SPREAD_PAGE:
2287 : 0 : retval = update_flag(CS_SPREAD_PAGE, cs, val);
2288 : 0 : break;
2289 : : case FILE_SPREAD_SLAB:
2290 : 0 : retval = update_flag(CS_SPREAD_SLAB, cs, val);
2291 : 0 : break;
2292 : : default:
2293 : : retval = -EINVAL;
2294 : : break;
2295 : : }
2296 : : out_unlock:
2297 : 0 : percpu_up_write(&cpuset_rwsem);
2298 : : put_online_cpus();
2299 : 0 : return retval;
2300 : : }
2301 : :
2302 : 0 : static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
2303 : : s64 val)
2304 : : {
2305 : : struct cpuset *cs = css_cs(css);
2306 : 0 : cpuset_filetype_t type = cft->private;
2307 : : int retval = -ENODEV;
2308 : :
2309 : : get_online_cpus();
2310 : 0 : percpu_down_write(&cpuset_rwsem);
2311 [ # # ]: 0 : if (!is_cpuset_online(cs))
2312 : : goto out_unlock;
2313 : :
2314 [ # # ]: 0 : switch (type) {
2315 : : case FILE_SCHED_RELAX_DOMAIN_LEVEL:
2316 : 0 : retval = update_relax_domain_level(cs, val);
2317 : 0 : break;
2318 : : default:
2319 : : retval = -EINVAL;
2320 : : break;
2321 : : }
2322 : : out_unlock:
2323 : 0 : percpu_up_write(&cpuset_rwsem);
2324 : : put_online_cpus();
2325 : 0 : return retval;
2326 : : }
2327 : :
2328 : : /*
2329 : : * Common handling for a write to a "cpus" or "mems" file.
2330 : : */
2331 : 0 : static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
2332 : : char *buf, size_t nbytes, loff_t off)
2333 : : {
2334 : 0 : struct cpuset *cs = css_cs(of_css(of));
2335 : : struct cpuset *trialcs;
2336 : : int retval = -ENODEV;
2337 : :
2338 : : buf = strstrip(buf);
2339 : :
2340 : : /*
2341 : : * CPU or memory hotunplug may leave @cs w/o any execution
2342 : : * resources, in which case the hotplug code asynchronously updates
2343 : : * configuration and transfers all tasks to the nearest ancestor
2344 : : * which can execute.
2345 : : *
2346 : : * As writes to "cpus" or "mems" may restore @cs's execution
2347 : : * resources, wait for the previously scheduled operations before
2348 : : * proceeding, so that we don't end up keep removing tasks added
2349 : : * after execution capability is restored.
2350 : : *
2351 : : * cpuset_hotplug_work calls back into cgroup core via
2352 : : * cgroup_transfer_tasks() and waiting for it from a cgroupfs
2353 : : * operation like this one can lead to a deadlock through kernfs
2354 : : * active_ref protection. Let's break the protection. Losing the
2355 : : * protection is okay as we check whether @cs is online after
2356 : : * grabbing cpuset_mutex anyway. This only happens on the legacy
2357 : : * hierarchies.
2358 : : */
2359 : : css_get(&cs->css);
2360 : 0 : kernfs_break_active_protection(of->kn);
2361 : 0 : flush_work(&cpuset_hotplug_work);
2362 : :
2363 : : get_online_cpus();
2364 : 0 : percpu_down_write(&cpuset_rwsem);
2365 [ # # ]: 0 : if (!is_cpuset_online(cs))
2366 : : goto out_unlock;
2367 : :
2368 : 0 : trialcs = alloc_trial_cpuset(cs);
2369 [ # # ]: 0 : if (!trialcs) {
2370 : : retval = -ENOMEM;
2371 : : goto out_unlock;
2372 : : }
2373 : :
2374 [ # # # ]: 0 : switch (of_cft(of)->private) {
2375 : : case FILE_CPULIST:
2376 : 0 : retval = update_cpumask(cs, trialcs, buf);
2377 : 0 : break;
2378 : : case FILE_MEMLIST:
2379 : 0 : retval = update_nodemask(cs, trialcs, buf);
2380 : 0 : break;
2381 : : default:
2382 : : retval = -EINVAL;
2383 : : break;
2384 : : }
2385 : :
2386 : : free_cpuset(trialcs);
2387 : : out_unlock:
2388 : 0 : percpu_up_write(&cpuset_rwsem);
2389 : : put_online_cpus();
2390 : 0 : kernfs_unbreak_active_protection(of->kn);
2391 : : css_put(&cs->css);
2392 : 0 : flush_workqueue(cpuset_migrate_mm_wq);
2393 [ # # ]: 0 : return retval ?: nbytes;
2394 : : }
2395 : :
2396 : : /*
2397 : : * These ascii lists should be read in a single call, by using a user
2398 : : * buffer large enough to hold the entire map. If read in smaller
2399 : : * chunks, there is no guarantee of atomicity. Since the display format
2400 : : * used, list of ranges of sequential numbers, is variable length,
2401 : : * and since these maps can change value dynamically, one could read
2402 : : * gibberish by doing partial reads while a list was changing.
2403 : : */
2404 : 0 : static int cpuset_common_seq_show(struct seq_file *sf, void *v)
2405 : : {
2406 : : struct cpuset *cs = css_cs(seq_css(sf));
2407 : 0 : cpuset_filetype_t type = seq_cft(sf)->private;
2408 : : int ret = 0;
2409 : :
2410 : : spin_lock_irq(&callback_lock);
2411 : :
2412 [ # # # # : 0 : switch (type) {
# # ]
2413 : : case FILE_CPULIST:
2414 : 0 : seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed));
2415 : 0 : break;
2416 : : case FILE_MEMLIST:
2417 : 0 : seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
2418 : 0 : break;
2419 : : case FILE_EFFECTIVE_CPULIST:
2420 : 0 : seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
2421 : 0 : break;
2422 : : case FILE_EFFECTIVE_MEMLIST:
2423 : 0 : seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
2424 : 0 : break;
2425 : : case FILE_SUBPARTS_CPULIST:
2426 : 0 : seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->subparts_cpus));
2427 : 0 : break;
2428 : : default:
2429 : : ret = -EINVAL;
2430 : : }
2431 : :
2432 : : spin_unlock_irq(&callback_lock);
2433 : 0 : return ret;
2434 : : }
2435 : :
2436 : 0 : static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
2437 : : {
2438 : : struct cpuset *cs = css_cs(css);
2439 : 0 : cpuset_filetype_t type = cft->private;
2440 [ # # # # : 0 : switch (type) {
# # # # #
# ]
2441 : : case FILE_CPU_EXCLUSIVE:
2442 : 0 : return is_cpu_exclusive(cs);
2443 : : case FILE_MEM_EXCLUSIVE:
2444 : 0 : return is_mem_exclusive(cs);
2445 : : case FILE_MEM_HARDWALL:
2446 : 0 : return is_mem_hardwall(cs);
2447 : : case FILE_SCHED_LOAD_BALANCE:
2448 : 0 : return is_sched_load_balance(cs);
2449 : : case FILE_MEMORY_MIGRATE:
2450 : 0 : return is_memory_migrate(cs);
2451 : : case FILE_MEMORY_PRESSURE_ENABLED:
2452 : 0 : return cpuset_memory_pressure_enabled;
2453 : : case FILE_MEMORY_PRESSURE:
2454 : 0 : return fmeter_getrate(&cs->fmeter);
2455 : : case FILE_SPREAD_PAGE:
2456 : 0 : return is_spread_page(cs);
2457 : : case FILE_SPREAD_SLAB:
2458 : 0 : return is_spread_slab(cs);
2459 : : default:
2460 : 0 : BUG();
2461 : : }
2462 : :
2463 : : /* Unreachable but makes gcc happy */
2464 : : return 0;
2465 : : }
2466 : :
2467 : 0 : static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
2468 : : {
2469 : : struct cpuset *cs = css_cs(css);
2470 : 0 : cpuset_filetype_t type = cft->private;
2471 [ # # ]: 0 : switch (type) {
2472 : : case FILE_SCHED_RELAX_DOMAIN_LEVEL:
2473 : 0 : return cs->relax_domain_level;
2474 : : default:
2475 : 0 : BUG();
2476 : : }
2477 : :
2478 : : /* Unrechable but makes gcc happy */
2479 : : return 0;
2480 : : }
2481 : :
2482 : 0 : static int sched_partition_show(struct seq_file *seq, void *v)
2483 : : {
2484 : : struct cpuset *cs = css_cs(seq_css(seq));
2485 : :
2486 [ # # # # ]: 0 : switch (cs->partition_root_state) {
2487 : : case PRS_ENABLED:
2488 : 0 : seq_puts(seq, "root\n");
2489 : 0 : break;
2490 : : case PRS_DISABLED:
2491 : 0 : seq_puts(seq, "member\n");
2492 : 0 : break;
2493 : : case PRS_ERROR:
2494 : 0 : seq_puts(seq, "root invalid\n");
2495 : 0 : break;
2496 : : }
2497 : 0 : return 0;
2498 : : }
2499 : :
2500 : 0 : static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
2501 : : size_t nbytes, loff_t off)
2502 : : {
2503 : 0 : struct cpuset *cs = css_cs(of_css(of));
2504 : : int val;
2505 : : int retval = -ENODEV;
2506 : :
2507 : : buf = strstrip(buf);
2508 : :
2509 : : /*
2510 : : * Convert "root" to ENABLED, and convert "member" to DISABLED.
2511 : : */
2512 [ # # ]: 0 : if (!strcmp(buf, "root"))
2513 : : val = PRS_ENABLED;
2514 [ # # ]: 0 : else if (!strcmp(buf, "member"))
2515 : : val = PRS_DISABLED;
2516 : : else
2517 : : return -EINVAL;
2518 : :
2519 : : css_get(&cs->css);
2520 : : get_online_cpus();
2521 : 0 : percpu_down_write(&cpuset_rwsem);
2522 [ # # ]: 0 : if (!is_cpuset_online(cs))
2523 : : goto out_unlock;
2524 : :
2525 : 0 : retval = update_prstate(cs, val);
2526 : : out_unlock:
2527 : 0 : percpu_up_write(&cpuset_rwsem);
2528 : : put_online_cpus();
2529 : : css_put(&cs->css);
2530 [ # # ]: 0 : return retval ?: nbytes;
2531 : : }
2532 : :
2533 : : /*
2534 : : * for the common functions, 'private' gives the type of file
2535 : : */
2536 : :
2537 : : static struct cftype legacy_files[] = {
2538 : : {
2539 : : .name = "cpus",
2540 : : .seq_show = cpuset_common_seq_show,
2541 : : .write = cpuset_write_resmask,
2542 : : .max_write_len = (100U + 6 * NR_CPUS),
2543 : : .private = FILE_CPULIST,
2544 : : },
2545 : :
2546 : : {
2547 : : .name = "mems",
2548 : : .seq_show = cpuset_common_seq_show,
2549 : : .write = cpuset_write_resmask,
2550 : : .max_write_len = (100U + 6 * MAX_NUMNODES),
2551 : : .private = FILE_MEMLIST,
2552 : : },
2553 : :
2554 : : {
2555 : : .name = "effective_cpus",
2556 : : .seq_show = cpuset_common_seq_show,
2557 : : .private = FILE_EFFECTIVE_CPULIST,
2558 : : },
2559 : :
2560 : : {
2561 : : .name = "effective_mems",
2562 : : .seq_show = cpuset_common_seq_show,
2563 : : .private = FILE_EFFECTIVE_MEMLIST,
2564 : : },
2565 : :
2566 : : {
2567 : : .name = "cpu_exclusive",
2568 : : .read_u64 = cpuset_read_u64,
2569 : : .write_u64 = cpuset_write_u64,
2570 : : .private = FILE_CPU_EXCLUSIVE,
2571 : : },
2572 : :
2573 : : {
2574 : : .name = "mem_exclusive",
2575 : : .read_u64 = cpuset_read_u64,
2576 : : .write_u64 = cpuset_write_u64,
2577 : : .private = FILE_MEM_EXCLUSIVE,
2578 : : },
2579 : :
2580 : : {
2581 : : .name = "mem_hardwall",
2582 : : .read_u64 = cpuset_read_u64,
2583 : : .write_u64 = cpuset_write_u64,
2584 : : .private = FILE_MEM_HARDWALL,
2585 : : },
2586 : :
2587 : : {
2588 : : .name = "sched_load_balance",
2589 : : .read_u64 = cpuset_read_u64,
2590 : : .write_u64 = cpuset_write_u64,
2591 : : .private = FILE_SCHED_LOAD_BALANCE,
2592 : : },
2593 : :
2594 : : {
2595 : : .name = "sched_relax_domain_level",
2596 : : .read_s64 = cpuset_read_s64,
2597 : : .write_s64 = cpuset_write_s64,
2598 : : .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
2599 : : },
2600 : :
2601 : : {
2602 : : .name = "memory_migrate",
2603 : : .read_u64 = cpuset_read_u64,
2604 : : .write_u64 = cpuset_write_u64,
2605 : : .private = FILE_MEMORY_MIGRATE,
2606 : : },
2607 : :
2608 : : {
2609 : : .name = "memory_pressure",
2610 : : .read_u64 = cpuset_read_u64,
2611 : : .private = FILE_MEMORY_PRESSURE,
2612 : : },
2613 : :
2614 : : {
2615 : : .name = "memory_spread_page",
2616 : : .read_u64 = cpuset_read_u64,
2617 : : .write_u64 = cpuset_write_u64,
2618 : : .private = FILE_SPREAD_PAGE,
2619 : : },
2620 : :
2621 : : {
2622 : : .name = "memory_spread_slab",
2623 : : .read_u64 = cpuset_read_u64,
2624 : : .write_u64 = cpuset_write_u64,
2625 : : .private = FILE_SPREAD_SLAB,
2626 : : },
2627 : :
2628 : : {
2629 : : .name = "memory_pressure_enabled",
2630 : : .flags = CFTYPE_ONLY_ON_ROOT,
2631 : : .read_u64 = cpuset_read_u64,
2632 : : .write_u64 = cpuset_write_u64,
2633 : : .private = FILE_MEMORY_PRESSURE_ENABLED,
2634 : : },
2635 : :
2636 : : { } /* terminate */
2637 : : };
2638 : :
2639 : : /*
2640 : : * This is currently a minimal set for the default hierarchy. It can be
2641 : : * expanded later on by migrating more features and control files from v1.
2642 : : */
2643 : : static struct cftype dfl_files[] = {
2644 : : {
2645 : : .name = "cpus",
2646 : : .seq_show = cpuset_common_seq_show,
2647 : : .write = cpuset_write_resmask,
2648 : : .max_write_len = (100U + 6 * NR_CPUS),
2649 : : .private = FILE_CPULIST,
2650 : : .flags = CFTYPE_NOT_ON_ROOT,
2651 : : },
2652 : :
2653 : : {
2654 : : .name = "mems",
2655 : : .seq_show = cpuset_common_seq_show,
2656 : : .write = cpuset_write_resmask,
2657 : : .max_write_len = (100U + 6 * MAX_NUMNODES),
2658 : : .private = FILE_MEMLIST,
2659 : : .flags = CFTYPE_NOT_ON_ROOT,
2660 : : },
2661 : :
2662 : : {
2663 : : .name = "cpus.effective",
2664 : : .seq_show = cpuset_common_seq_show,
2665 : : .private = FILE_EFFECTIVE_CPULIST,
2666 : : },
2667 : :
2668 : : {
2669 : : .name = "mems.effective",
2670 : : .seq_show = cpuset_common_seq_show,
2671 : : .private = FILE_EFFECTIVE_MEMLIST,
2672 : : },
2673 : :
2674 : : {
2675 : : .name = "cpus.partition",
2676 : : .seq_show = sched_partition_show,
2677 : : .write = sched_partition_write,
2678 : : .private = FILE_PARTITION_ROOT,
2679 : : .flags = CFTYPE_NOT_ON_ROOT,
2680 : : },
2681 : :
2682 : : {
2683 : : .name = "cpus.subpartitions",
2684 : : .seq_show = cpuset_common_seq_show,
2685 : : .private = FILE_SUBPARTS_CPULIST,
2686 : : .flags = CFTYPE_DEBUG,
2687 : : },
2688 : :
2689 : : { } /* terminate */
2690 : : };
2691 : :
2692 : :
2693 : : /*
2694 : : * cpuset_css_alloc - allocate a cpuset css
2695 : : * cgrp: control group that the new cpuset will be part of
2696 : : */
2697 : :
2698 : : static struct cgroup_subsys_state *
2699 : 404 : cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
2700 : : {
2701 : : struct cpuset *cs;
2702 : :
2703 [ - + ]: 404 : if (!parent_css)
2704 : : return &top_cpuset.css;
2705 : :
2706 : 0 : cs = kzalloc(sizeof(*cs), GFP_KERNEL);
2707 [ # # ]: 0 : if (!cs)
2708 : : return ERR_PTR(-ENOMEM);
2709 : :
2710 [ # # ]: 0 : if (alloc_cpumasks(cs, NULL)) {
2711 : 0 : kfree(cs);
2712 : 0 : return ERR_PTR(-ENOMEM);
2713 : : }
2714 : :
2715 : 0 : set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
2716 : : nodes_clear(cs->mems_allowed);
2717 : : nodes_clear(cs->effective_mems);
2718 : : fmeter_init(&cs->fmeter);
2719 : 0 : cs->relax_domain_level = -1;
2720 : :
2721 : 0 : return &cs->css;
2722 : : }
2723 : :
2724 : 404 : static int cpuset_css_online(struct cgroup_subsys_state *css)
2725 : : {
2726 : : struct cpuset *cs = css_cs(css);
2727 : : struct cpuset *parent = parent_cs(cs);
2728 : : struct cpuset *tmp_cs;
2729 : : struct cgroup_subsys_state *pos_css;
2730 : :
2731 [ - + ]: 404 : if (!parent)
2732 : : return 0;
2733 : :
2734 : : get_online_cpus();
2735 : 0 : percpu_down_write(&cpuset_rwsem);
2736 : :
2737 : 0 : set_bit(CS_ONLINE, &cs->flags);
2738 [ # # ]: 0 : if (is_spread_page(parent))
2739 : 0 : set_bit(CS_SPREAD_PAGE, &cs->flags);
2740 [ # # ]: 0 : if (is_spread_slab(parent))
2741 : 0 : set_bit(CS_SPREAD_SLAB, &cs->flags);
2742 : :
2743 : : cpuset_inc();
2744 : :
2745 : : spin_lock_irq(&callback_lock);
2746 [ # # ]: 0 : if (is_in_v2_mode()) {
2747 : : cpumask_copy(cs->effective_cpus, parent->effective_cpus);
2748 : 0 : cs->effective_mems = parent->effective_mems;
2749 : 0 : cs->use_parent_ecpus = true;
2750 : 0 : parent->child_ecpus_count++;
2751 : : }
2752 : : spin_unlock_irq(&callback_lock);
2753 : :
2754 [ # # ]: 0 : if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
2755 : : goto out_unlock;
2756 : :
2757 : : /*
2758 : : * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
2759 : : * set. This flag handling is implemented in cgroup core for
2760 : : * histrical reasons - the flag may be specified during mount.
2761 : : *
2762 : : * Currently, if any sibling cpusets have exclusive cpus or mem, we
2763 : : * refuse to clone the configuration - thereby refusing the task to
2764 : : * be entered, and as a result refusing the sys_unshare() or
2765 : : * clone() which initiated it. If this becomes a problem for some
2766 : : * users who wish to allow that scenario, then this could be
2767 : : * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
2768 : : * (and likewise for mems) to the new cgroup.
2769 : : */
2770 : : rcu_read_lock();
2771 [ # # # # ]: 0 : cpuset_for_each_child(tmp_cs, pos_css, parent) {
2772 [ # # # # ]: 0 : if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
2773 : : rcu_read_unlock();
2774 : : goto out_unlock;
2775 : : }
2776 : : }
2777 : : rcu_read_unlock();
2778 : :
2779 : : spin_lock_irq(&callback_lock);
2780 : 0 : cs->mems_allowed = parent->mems_allowed;
2781 : 0 : cs->effective_mems = parent->mems_allowed;
2782 : : cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
2783 : : cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
2784 : : spin_unlock_irq(&callback_lock);
2785 : : out_unlock:
2786 : 0 : percpu_up_write(&cpuset_rwsem);
2787 : : put_online_cpus();
2788 : 0 : return 0;
2789 : : }
2790 : :
2791 : : /*
2792 : : * If the cpuset being removed has its flag 'sched_load_balance'
2793 : : * enabled, then simulate turning sched_load_balance off, which
2794 : : * will call rebuild_sched_domains_locked(). That is not needed
2795 : : * in the default hierarchy where only changes in partition
2796 : : * will cause repartitioning.
2797 : : *
2798 : : * If the cpuset has the 'sched.partition' flag enabled, simulate
2799 : : * turning 'sched.partition" off.
2800 : : */
2801 : :
2802 : 0 : static void cpuset_css_offline(struct cgroup_subsys_state *css)
2803 : : {
2804 : : struct cpuset *cs = css_cs(css);
2805 : :
2806 : : get_online_cpus();
2807 : 0 : percpu_down_write(&cpuset_rwsem);
2808 : :
2809 [ # # ]: 0 : if (is_partition_root(cs))
2810 : 0 : update_prstate(cs, 0);
2811 : :
2812 [ # # # # ]: 0 : if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
2813 : : is_sched_load_balance(cs))
2814 : 0 : update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
2815 : :
2816 [ # # ]: 0 : if (cs->use_parent_ecpus) {
2817 : : struct cpuset *parent = parent_cs(cs);
2818 : :
2819 : 0 : cs->use_parent_ecpus = false;
2820 : 0 : parent->child_ecpus_count--;
2821 : : }
2822 : :
2823 : : cpuset_dec();
2824 : 0 : clear_bit(CS_ONLINE, &cs->flags);
2825 : :
2826 : 0 : percpu_up_write(&cpuset_rwsem);
2827 : : put_online_cpus();
2828 : 0 : }
2829 : :
2830 : 0 : static void cpuset_css_free(struct cgroup_subsys_state *css)
2831 : : {
2832 : : struct cpuset *cs = css_cs(css);
2833 : :
2834 : : free_cpuset(cs);
2835 : 0 : }
2836 : :
2837 : 808 : static void cpuset_bind(struct cgroup_subsys_state *root_css)
2838 : : {
2839 : 808 : percpu_down_write(&cpuset_rwsem);
2840 : : spin_lock_irq(&callback_lock);
2841 : :
2842 [ + + ]: 808 : if (is_in_v2_mode()) {
2843 : : cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
2844 : 404 : top_cpuset.mems_allowed = node_possible_map;
2845 : : } else {
2846 : : cpumask_copy(top_cpuset.cpus_allowed,
2847 : : top_cpuset.effective_cpus);
2848 : 404 : top_cpuset.mems_allowed = top_cpuset.effective_mems;
2849 : : }
2850 : :
2851 : : spin_unlock_irq(&callback_lock);
2852 : 808 : percpu_up_write(&cpuset_rwsem);
2853 : 808 : }
2854 : :
2855 : : /*
2856 : : * Make sure the new task conform to the current state of its parent,
2857 : : * which could have been changed by cpuset just after it inherits the
2858 : : * state from the parent and before it sits on the cgroup's task list.
2859 : : */
2860 : 465082 : static void cpuset_fork(struct task_struct *task)
2861 : : {
2862 [ - + ]: 465082 : if (task_css_is_root(task, cpuset_cgrp_id))
2863 : 465082 : return;
2864 : :
2865 : 0 : set_cpus_allowed_ptr(task, current->cpus_ptr);
2866 : 0 : task->mems_allowed = current->mems_allowed;
2867 : : }
2868 : :
2869 : : struct cgroup_subsys cpuset_cgrp_subsys = {
2870 : : .css_alloc = cpuset_css_alloc,
2871 : : .css_online = cpuset_css_online,
2872 : : .css_offline = cpuset_css_offline,
2873 : : .css_free = cpuset_css_free,
2874 : : .can_attach = cpuset_can_attach,
2875 : : .cancel_attach = cpuset_cancel_attach,
2876 : : .attach = cpuset_attach,
2877 : : .post_attach = cpuset_post_attach,
2878 : : .bind = cpuset_bind,
2879 : : .fork = cpuset_fork,
2880 : : .legacy_cftypes = legacy_files,
2881 : : .dfl_cftypes = dfl_files,
2882 : : .early_init = true,
2883 : : .threaded = true,
2884 : : };
2885 : :
2886 : : /**
2887 : : * cpuset_init - initialize cpusets at system boot
2888 : : *
2889 : : * Description: Initialize top_cpuset
2890 : : **/
2891 : :
2892 : 404 : int __init cpuset_init(void)
2893 : : {
2894 [ - + ]: 404 : BUG_ON(percpu_init_rwsem(&cpuset_rwsem));
2895 : :
2896 : : BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
2897 : : BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
2898 : : BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
2899 : :
2900 : : cpumask_setall(top_cpuset.cpus_allowed);
2901 : : nodes_setall(top_cpuset.mems_allowed);
2902 : : cpumask_setall(top_cpuset.effective_cpus);
2903 : : nodes_setall(top_cpuset.effective_mems);
2904 : :
2905 : : fmeter_init(&top_cpuset.fmeter);
2906 : 404 : set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
2907 : 404 : top_cpuset.relax_domain_level = -1;
2908 : :
2909 : : BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
2910 : :
2911 : 404 : return 0;
2912 : : }
2913 : :
2914 : : /*
2915 : : * If CPU and/or memory hotplug handlers, below, unplug any CPUs
2916 : : * or memory nodes, we need to walk over the cpuset hierarchy,
2917 : : * removing that CPU or node from all cpusets. If this removes the
2918 : : * last CPU or node from a cpuset, then move the tasks in the empty
2919 : : * cpuset to its next-highest non-empty parent.
2920 : : */
2921 : 0 : static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
2922 : : {
2923 : : struct cpuset *parent;
2924 : :
2925 : : /*
2926 : : * Find its next-highest non-empty parent, (top cpuset
2927 : : * has online cpus, so can't be empty).
2928 : : */
2929 : : parent = parent_cs(cs);
2930 [ # # # # ]: 0 : while (cpumask_empty(parent->cpus_allowed) ||
2931 : : nodes_empty(parent->mems_allowed))
2932 : : parent = parent_cs(parent);
2933 : :
2934 [ # # ]: 0 : if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
2935 : 0 : pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
2936 : 0 : pr_cont_cgroup_name(cs->css.cgroup);
2937 : 0 : pr_cont("\n");
2938 : : }
2939 : 0 : }
2940 : :
2941 : : static void
2942 : 0 : hotplug_update_tasks_legacy(struct cpuset *cs,
2943 : : struct cpumask *new_cpus, nodemask_t *new_mems,
2944 : : bool cpus_updated, bool mems_updated)
2945 : : {
2946 : : bool is_empty;
2947 : :
2948 : : spin_lock_irq(&callback_lock);
2949 : : cpumask_copy(cs->cpus_allowed, new_cpus);
2950 : : cpumask_copy(cs->effective_cpus, new_cpus);
2951 : 0 : cs->mems_allowed = *new_mems;
2952 : 0 : cs->effective_mems = *new_mems;
2953 : : spin_unlock_irq(&callback_lock);
2954 : :
2955 : : /*
2956 : : * Don't call update_tasks_cpumask() if the cpuset becomes empty,
2957 : : * as the tasks will be migratecd to an ancestor.
2958 : : */
2959 [ # # # # ]: 0 : if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
2960 : 0 : update_tasks_cpumask(cs);
2961 [ # # # # ]: 0 : if (mems_updated && !nodes_empty(cs->mems_allowed))
2962 : 0 : update_tasks_nodemask(cs);
2963 : :
2964 [ # # # # ]: 0 : is_empty = cpumask_empty(cs->cpus_allowed) ||
2965 : : nodes_empty(cs->mems_allowed);
2966 : :
2967 : 0 : percpu_up_write(&cpuset_rwsem);
2968 : :
2969 : : /*
2970 : : * Move tasks to the nearest ancestor with execution resources,
2971 : : * This is full cgroup operation which will also call back into
2972 : : * cpuset. Should be done outside any lock.
2973 : : */
2974 [ # # ]: 0 : if (is_empty)
2975 : 0 : remove_tasks_in_empty_cpuset(cs);
2976 : :
2977 : 0 : percpu_down_write(&cpuset_rwsem);
2978 : 0 : }
2979 : :
2980 : : static void
2981 : 0 : hotplug_update_tasks(struct cpuset *cs,
2982 : : struct cpumask *new_cpus, nodemask_t *new_mems,
2983 : : bool cpus_updated, bool mems_updated)
2984 : : {
2985 [ # # ]: 0 : if (cpumask_empty(new_cpus))
2986 : : cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
2987 [ # # ]: 0 : if (nodes_empty(*new_mems))
2988 : 0 : *new_mems = parent_cs(cs)->effective_mems;
2989 : :
2990 : : spin_lock_irq(&callback_lock);
2991 : : cpumask_copy(cs->effective_cpus, new_cpus);
2992 : 0 : cs->effective_mems = *new_mems;
2993 : : spin_unlock_irq(&callback_lock);
2994 : :
2995 [ # # ]: 0 : if (cpus_updated)
2996 : 0 : update_tasks_cpumask(cs);
2997 [ # # ]: 0 : if (mems_updated)
2998 : 0 : update_tasks_nodemask(cs);
2999 : 0 : }
3000 : :
3001 : : static bool force_rebuild;
3002 : :
3003 : 0 : void cpuset_force_rebuild(void)
3004 : : {
3005 : 0 : force_rebuild = true;
3006 : 0 : }
3007 : :
3008 : : /**
3009 : : * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
3010 : : * @cs: cpuset in interest
3011 : : * @tmp: the tmpmasks structure pointer
3012 : : *
3013 : : * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
3014 : : * offline, update @cs accordingly. If @cs ends up with no CPU or memory,
3015 : : * all its tasks are moved to the nearest ancestor with both resources.
3016 : : */
3017 : 0 : static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
3018 : : {
3019 : : static cpumask_t new_cpus;
3020 : : static nodemask_t new_mems;
3021 : : bool cpus_updated;
3022 : : bool mems_updated;
3023 : : struct cpuset *parent;
3024 : : retry:
3025 [ # # # # ]: 0 : wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
3026 : :
3027 : 0 : percpu_down_write(&cpuset_rwsem);
3028 : :
3029 : : /*
3030 : : * We have raced with task attaching. We wait until attaching
3031 : : * is finished, so we won't attach a task to an empty cpuset.
3032 : : */
3033 [ # # ]: 0 : if (cs->attach_in_progress) {
3034 : 0 : percpu_up_write(&cpuset_rwsem);
3035 : 0 : goto retry;
3036 : : }
3037 : :
3038 : : parent = parent_cs(cs);
3039 : 0 : compute_effective_cpumask(&new_cpus, cs, parent);
3040 : : nodes_and(new_mems, cs->mems_allowed, parent->effective_mems);
3041 : :
3042 [ # # ]: 0 : if (cs->nr_subparts_cpus)
3043 : : /*
3044 : : * Make sure that CPUs allocated to child partitions
3045 : : * do not show up in effective_cpus.
3046 : : */
3047 : : cpumask_andnot(&new_cpus, &new_cpus, cs->subparts_cpus);
3048 : :
3049 [ # # # # ]: 0 : if (!tmp || !cs->partition_root_state)
3050 : : goto update_tasks;
3051 : :
3052 : : /*
3053 : : * In the unlikely event that a partition root has empty
3054 : : * effective_cpus or its parent becomes erroneous, we have to
3055 : : * transition it to the erroneous state.
3056 : : */
3057 [ # # # # : 0 : if (is_partition_root(cs) && (cpumask_empty(&new_cpus) ||
# # ]
3058 : 0 : (parent->partition_root_state == PRS_ERROR))) {
3059 [ # # ]: 0 : if (cs->nr_subparts_cpus) {
3060 : 0 : cs->nr_subparts_cpus = 0;
3061 : : cpumask_clear(cs->subparts_cpus);
3062 : 0 : compute_effective_cpumask(&new_cpus, cs, parent);
3063 : : }
3064 : :
3065 : : /*
3066 : : * If the effective_cpus is empty because the child
3067 : : * partitions take away all the CPUs, we can keep
3068 : : * the current partition and let the child partitions
3069 : : * fight for available CPUs.
3070 : : */
3071 [ # # # # ]: 0 : if ((parent->partition_root_state == PRS_ERROR) ||
3072 : : cpumask_empty(&new_cpus)) {
3073 : 0 : update_parent_subparts_cpumask(cs, partcmd_disable,
3074 : : NULL, tmp);
3075 : 0 : cs->partition_root_state = PRS_ERROR;
3076 : : }
3077 : : cpuset_force_rebuild();
3078 : : }
3079 : :
3080 : : /*
3081 : : * On the other hand, an erroneous partition root may be transitioned
3082 : : * back to a regular one or a partition root with no CPU allocated
3083 : : * from the parent may change to erroneous.
3084 : : */
3085 [ # # # # ]: 0 : if (is_partition_root(parent) &&
3086 [ # # ]: 0 : ((cs->partition_root_state == PRS_ERROR) ||
3087 [ # # ]: 0 : !cpumask_intersects(&new_cpus, parent->subparts_cpus)) &&
3088 : 0 : update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp))
3089 : : cpuset_force_rebuild();
3090 : :
3091 : : update_tasks:
3092 : 0 : cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
3093 : 0 : mems_updated = !nodes_equal(new_mems, cs->effective_mems);
3094 : :
3095 [ # # ]: 0 : if (is_in_v2_mode())
3096 : 0 : hotplug_update_tasks(cs, &new_cpus, &new_mems,
3097 : : cpus_updated, mems_updated);
3098 : : else
3099 : 0 : hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
3100 : : cpus_updated, mems_updated);
3101 : :
3102 : 0 : percpu_up_write(&cpuset_rwsem);
3103 : 0 : }
3104 : :
3105 : : /**
3106 : : * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
3107 : : *
3108 : : * This function is called after either CPU or memory configuration has
3109 : : * changed and updates cpuset accordingly. The top_cpuset is always
3110 : : * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
3111 : : * order to make cpusets transparent (of no affect) on systems that are
3112 : : * actively using CPU hotplug but making no active use of cpusets.
3113 : : *
3114 : : * Non-root cpusets are only affected by offlining. If any CPUs or memory
3115 : : * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
3116 : : * all descendants.
3117 : : *
3118 : : * Note that CPU offlining during suspend is ignored. We don't modify
3119 : : * cpusets across suspend/resume cycles at all.
3120 : : */
3121 : 0 : static void cpuset_hotplug_workfn(struct work_struct *work)
3122 : : {
3123 : : static cpumask_t new_cpus;
3124 : : static nodemask_t new_mems;
3125 : : bool cpus_updated, mems_updated;
3126 : 0 : bool on_dfl = is_in_v2_mode();
3127 : : struct tmpmasks tmp, *ptmp = NULL;
3128 : :
3129 [ # # # # ]: 0 : if (on_dfl && !alloc_cpumasks(NULL, &tmp))
3130 : : ptmp = &tmp;
3131 : :
3132 : 0 : percpu_down_write(&cpuset_rwsem);
3133 : :
3134 : : /* fetch the available cpus/mems and find out which changed how */
3135 : : cpumask_copy(&new_cpus, cpu_active_mask);
3136 : 0 : new_mems = node_states[N_MEMORY];
3137 : :
3138 : : /*
3139 : : * If subparts_cpus is populated, it is likely that the check below
3140 : : * will produce a false positive on cpus_updated when the cpu list
3141 : : * isn't changed. It is extra work, but it is better to be safe.
3142 : : */
3143 : 0 : cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
3144 : 0 : mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
3145 : :
3146 : : /* synchronize cpus_allowed to cpu_active_mask */
3147 [ # # ]: 0 : if (cpus_updated) {
3148 : : spin_lock_irq(&callback_lock);
3149 [ # # ]: 0 : if (!on_dfl)
3150 : : cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
3151 : : /*
3152 : : * Make sure that CPUs allocated to child partitions
3153 : : * do not show up in effective_cpus. If no CPU is left,
3154 : : * we clear the subparts_cpus & let the child partitions
3155 : : * fight for the CPUs again.
3156 : : */
3157 [ # # ]: 0 : if (top_cpuset.nr_subparts_cpus) {
3158 [ # # ]: 0 : if (cpumask_subset(&new_cpus,
3159 : : top_cpuset.subparts_cpus)) {
3160 : 0 : top_cpuset.nr_subparts_cpus = 0;
3161 : : cpumask_clear(top_cpuset.subparts_cpus);
3162 : : } else {
3163 : : cpumask_andnot(&new_cpus, &new_cpus,
3164 : : top_cpuset.subparts_cpus);
3165 : : }
3166 : : }
3167 : : cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
3168 : : spin_unlock_irq(&callback_lock);
3169 : : /* we don't mess with cpumasks of tasks in top_cpuset */
3170 : : }
3171 : :
3172 : : /* synchronize mems_allowed to N_MEMORY */
3173 [ # # ]: 0 : if (mems_updated) {
3174 : : spin_lock_irq(&callback_lock);
3175 [ # # ]: 0 : if (!on_dfl)
3176 : 0 : top_cpuset.mems_allowed = new_mems;
3177 : 0 : top_cpuset.effective_mems = new_mems;
3178 : : spin_unlock_irq(&callback_lock);
3179 : 0 : update_tasks_nodemask(&top_cpuset);
3180 : : }
3181 : :
3182 : 0 : percpu_up_write(&cpuset_rwsem);
3183 : :
3184 : : /* if cpus or mems changed, we need to propagate to descendants */
3185 [ # # ]: 0 : if (cpus_updated || mems_updated) {
3186 : : struct cpuset *cs;
3187 : : struct cgroup_subsys_state *pos_css;
3188 : :
3189 : : rcu_read_lock();
3190 [ # # # # ]: 0 : cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
3191 [ # # # # ]: 0 : if (cs == &top_cpuset || !css_tryget_online(&cs->css))
3192 : 0 : continue;
3193 : : rcu_read_unlock();
3194 : :
3195 : 0 : cpuset_hotplug_update_tasks(cs, ptmp);
3196 : :
3197 : : rcu_read_lock();
3198 : : css_put(&cs->css);
3199 : : }
3200 : : rcu_read_unlock();
3201 : : }
3202 : :
3203 : : /* rebuild sched domains if cpus_allowed has changed */
3204 [ # # # # ]: 0 : if (cpus_updated || force_rebuild) {
3205 : 0 : force_rebuild = false;
3206 : 0 : rebuild_sched_domains();
3207 : : }
3208 : :
3209 : : free_cpumasks(NULL, ptmp);
3210 : 0 : }
3211 : :
3212 : 0 : void cpuset_update_active_cpus(void)
3213 : : {
3214 : : /*
3215 : : * We're inside cpu hotplug critical region which usually nests
3216 : : * inside cgroup synchronization. Bounce actual hotplug processing
3217 : : * to a work item to avoid reverse locking order.
3218 : : */
3219 : : schedule_work(&cpuset_hotplug_work);
3220 : 0 : }
3221 : :
3222 : 0 : void cpuset_wait_for_hotplug(void)
3223 : : {
3224 : 0 : flush_work(&cpuset_hotplug_work);
3225 : 0 : }
3226 : :
3227 : : /*
3228 : : * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
3229 : : * Call this routine anytime after node_states[N_MEMORY] changes.
3230 : : * See cpuset_update_active_cpus() for CPU hotplug handling.
3231 : : */
3232 : : static int cpuset_track_online_nodes(struct notifier_block *self,
3233 : : unsigned long action, void *arg)
3234 : : {
3235 : : schedule_work(&cpuset_hotplug_work);
3236 : : return NOTIFY_OK;
3237 : : }
3238 : :
3239 : : static struct notifier_block cpuset_track_online_nodes_nb = {
3240 : : .notifier_call = cpuset_track_online_nodes,
3241 : : .priority = 10, /* ??! */
3242 : : };
3243 : :
3244 : : /**
3245 : : * cpuset_init_smp - initialize cpus_allowed
3246 : : *
3247 : : * Description: Finish top cpuset after cpu, node maps are initialized
3248 : : */
3249 : 404 : void __init cpuset_init_smp(void)
3250 : : {
3251 : : cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
3252 : 404 : top_cpuset.mems_allowed = node_states[N_MEMORY];
3253 : 404 : top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
3254 : :
3255 : : cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
3256 : 404 : top_cpuset.effective_mems = node_states[N_MEMORY];
3257 : :
3258 : : register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
3259 : :
3260 : 404 : cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
3261 [ - + ]: 404 : BUG_ON(!cpuset_migrate_mm_wq);
3262 : 404 : }
3263 : :
3264 : : /**
3265 : : * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
3266 : : * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
3267 : : * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
3268 : : *
3269 : : * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
3270 : : * attached to the specified @tsk. Guaranteed to return some non-empty
3271 : : * subset of cpu_online_mask, even if this means going outside the
3272 : : * tasks cpuset.
3273 : : **/
3274 : :
3275 : 0 : void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
3276 : : {
3277 : : unsigned long flags;
3278 : :
3279 : 0 : spin_lock_irqsave(&callback_lock, flags);
3280 : : rcu_read_lock();
3281 : 0 : guarantee_online_cpus(task_cs(tsk), pmask);
3282 : : rcu_read_unlock();
3283 : : spin_unlock_irqrestore(&callback_lock, flags);
3284 : 0 : }
3285 : :
3286 : : /**
3287 : : * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
3288 : : * @tsk: pointer to task_struct with which the scheduler is struggling
3289 : : *
3290 : : * Description: In the case that the scheduler cannot find an allowed cpu in
3291 : : * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
3292 : : * mode however, this value is the same as task_cs(tsk)->effective_cpus,
3293 : : * which will not contain a sane cpumask during cases such as cpu hotplugging.
3294 : : * This is the absolute last resort for the scheduler and it is only used if
3295 : : * _every_ other avenue has been traveled.
3296 : : **/
3297 : :
3298 : 6060 : void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
3299 : : {
3300 : : rcu_read_lock();
3301 [ + - ]: 12120 : do_set_cpus_allowed(tsk, is_in_v2_mode() ?
3302 : : task_cs(tsk)->cpus_allowed : cpu_possible_mask);
3303 : : rcu_read_unlock();
3304 : :
3305 : : /*
3306 : : * We own tsk->cpus_allowed, nobody can change it under us.
3307 : : *
3308 : : * But we used cs && cs->cpus_allowed lockless and thus can
3309 : : * race with cgroup_attach_task() or update_cpumask() and get
3310 : : * the wrong tsk->cpus_allowed. However, both cases imply the
3311 : : * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
3312 : : * which takes task_rq_lock().
3313 : : *
3314 : : * If we are called after it dropped the lock we must see all
3315 : : * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
3316 : : * set any mask even if it is not right from task_cs() pov,
3317 : : * the pending set_cpus_allowed_ptr() will fix things.
3318 : : *
3319 : : * select_fallback_rq() will fix things ups and set cpu_possible_mask
3320 : : * if required.
3321 : : */
3322 : 6060 : }
3323 : :
3324 : 404 : void __init cpuset_init_current_mems_allowed(void)
3325 : : {
3326 : 404 : nodes_setall(current->mems_allowed);
3327 : 404 : }
3328 : :
3329 : : /**
3330 : : * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
3331 : : * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
3332 : : *
3333 : : * Description: Returns the nodemask_t mems_allowed of the cpuset
3334 : : * attached to the specified @tsk. Guaranteed to return some non-empty
3335 : : * subset of node_states[N_MEMORY], even if this means going outside the
3336 : : * tasks cpuset.
3337 : : **/
3338 : :
3339 : 0 : nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
3340 : : {
3341 : : nodemask_t mask;
3342 : : unsigned long flags;
3343 : :
3344 : 0 : spin_lock_irqsave(&callback_lock, flags);
3345 : : rcu_read_lock();
3346 : 0 : guarantee_online_mems(task_cs(tsk), &mask);
3347 : : rcu_read_unlock();
3348 : : spin_unlock_irqrestore(&callback_lock, flags);
3349 : :
3350 : 0 : return mask;
3351 : : }
3352 : :
3353 : : /**
3354 : : * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
3355 : : * @nodemask: the nodemask to be checked
3356 : : *
3357 : : * Are any of the nodes in the nodemask allowed in current->mems_allowed?
3358 : : */
3359 : 0 : int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
3360 : : {
3361 : 0 : return nodes_intersects(*nodemask, current->mems_allowed);
3362 : : }
3363 : :
3364 : : /*
3365 : : * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
3366 : : * mem_hardwall ancestor to the specified cpuset. Call holding
3367 : : * callback_lock. If no ancestor is mem_exclusive or mem_hardwall
3368 : : * (an unusual configuration), then returns the root cpuset.
3369 : : */
3370 : 0 : static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
3371 : : {
3372 [ # # # # : 0 : while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
# # ]
3373 : : cs = parent_cs(cs);
3374 : 0 : return cs;
3375 : : }
3376 : :
3377 : : /**
3378 : : * cpuset_node_allowed - Can we allocate on a memory node?
3379 : : * @node: is this an allowed node?
3380 : : * @gfp_mask: memory allocation flags
3381 : : *
3382 : : * If we're in interrupt, yes, we can always allocate. If @node is set in
3383 : : * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this
3384 : : * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
3385 : : * yes. If current has access to memory reserves as an oom victim, yes.
3386 : : * Otherwise, no.
3387 : : *
3388 : : * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
3389 : : * and do not allow allocations outside the current tasks cpuset
3390 : : * unless the task has been OOM killed.
3391 : : * GFP_KERNEL allocations are not so marked, so can escape to the
3392 : : * nearest enclosing hardwalled ancestor cpuset.
3393 : : *
3394 : : * Scanning up parent cpusets requires callback_lock. The
3395 : : * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
3396 : : * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
3397 : : * current tasks mems_allowed came up empty on the first pass over
3398 : : * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
3399 : : * cpuset are short of memory, might require taking the callback_lock.
3400 : : *
3401 : : * The first call here from mm/page_alloc:get_page_from_freelist()
3402 : : * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
3403 : : * so no allocation on a node outside the cpuset is allowed (unless
3404 : : * in interrupt, of course).
3405 : : *
3406 : : * The second pass through get_page_from_freelist() doesn't even call
3407 : : * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
3408 : : * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
3409 : : * in alloc_flags. That logic and the checks below have the combined
3410 : : * affect that:
3411 : : * in_interrupt - any node ok (current task context irrelevant)
3412 : : * GFP_ATOMIC - any node ok
3413 : : * tsk_is_oom_victim - any node ok
3414 : : * GFP_KERNEL - any node in enclosing hardwalled cpuset ok
3415 : : * GFP_USER - only nodes in current tasks mems allowed ok.
3416 : : */
3417 : 0 : bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
3418 : : {
3419 : : struct cpuset *cs; /* current cpuset ancestors */
3420 : : int allowed; /* is allocation in zone z allowed? */
3421 : : unsigned long flags;
3422 : :
3423 [ # # ]: 0 : if (in_interrupt())
3424 : : return true;
3425 [ # # ]: 0 : if (node_isset(node, current->mems_allowed))
3426 : : return true;
3427 : : /*
3428 : : * Allow tasks that have access to memory reserves because they have
3429 : : * been OOM killed to get memory anywhere.
3430 : : */
3431 [ # # ]: 0 : if (unlikely(tsk_is_oom_victim(current)))
3432 : : return true;
3433 [ # # ]: 0 : if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
3434 : : return false;
3435 : :
3436 [ # # ]: 0 : if (current->flags & PF_EXITING) /* Let dying task have memory */
3437 : : return true;
3438 : :
3439 : : /* Not hardwall and node outside mems_allowed: scan up cpusets */
3440 : 0 : spin_lock_irqsave(&callback_lock, flags);
3441 : :
3442 : : rcu_read_lock();
3443 : 0 : cs = nearest_hardwall_ancestor(task_cs(current));
3444 : 0 : allowed = node_isset(node, cs->mems_allowed);
3445 : : rcu_read_unlock();
3446 : :
3447 : : spin_unlock_irqrestore(&callback_lock, flags);
3448 : 0 : return allowed;
3449 : : }
3450 : :
3451 : : /**
3452 : : * cpuset_mem_spread_node() - On which node to begin search for a file page
3453 : : * cpuset_slab_spread_node() - On which node to begin search for a slab page
3454 : : *
3455 : : * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
3456 : : * tasks in a cpuset with is_spread_page or is_spread_slab set),
3457 : : * and if the memory allocation used cpuset_mem_spread_node()
3458 : : * to determine on which node to start looking, as it will for
3459 : : * certain page cache or slab cache pages such as used for file
3460 : : * system buffers and inode caches, then instead of starting on the
3461 : : * local node to look for a free page, rather spread the starting
3462 : : * node around the tasks mems_allowed nodes.
3463 : : *
3464 : : * We don't have to worry about the returned node being offline
3465 : : * because "it can't happen", and even if it did, it would be ok.
3466 : : *
3467 : : * The routines calling guarantee_online_mems() are careful to
3468 : : * only set nodes in task->mems_allowed that are online. So it
3469 : : * should not be possible for the following code to return an
3470 : : * offline node. But if it did, that would be ok, as this routine
3471 : : * is not returning the node where the allocation must be, only
3472 : : * the node where the search should start. The zonelist passed to
3473 : : * __alloc_pages() will include all nodes. If the slab allocator
3474 : : * is passed an offline node, it will fall back to the local node.
3475 : : * See kmem_cache_alloc_node().
3476 : : */
3477 : :
3478 : : static int cpuset_spread_node(int *rotor)
3479 : : {
3480 : 0 : return *rotor = next_node_in(*rotor, current->mems_allowed);
3481 : : }
3482 : :
3483 : 0 : int cpuset_mem_spread_node(void)
3484 : : {
3485 [ # # ]: 0 : if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
3486 : 0 : current->cpuset_mem_spread_rotor =
3487 : : node_random(¤t->mems_allowed);
3488 : :
3489 : 0 : return cpuset_spread_node(¤t->cpuset_mem_spread_rotor);
3490 : : }
3491 : :
3492 : 0 : int cpuset_slab_spread_node(void)
3493 : : {
3494 [ # # ]: 0 : if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
3495 : 0 : current->cpuset_slab_spread_rotor =
3496 : : node_random(¤t->mems_allowed);
3497 : :
3498 : 0 : return cpuset_spread_node(¤t->cpuset_slab_spread_rotor);
3499 : : }
3500 : :
3501 : : EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
3502 : :
3503 : : /**
3504 : : * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
3505 : : * @tsk1: pointer to task_struct of some task.
3506 : : * @tsk2: pointer to task_struct of some other task.
3507 : : *
3508 : : * Description: Return true if @tsk1's mems_allowed intersects the
3509 : : * mems_allowed of @tsk2. Used by the OOM killer to determine if
3510 : : * one of the task's memory usage might impact the memory available
3511 : : * to the other.
3512 : : **/
3513 : :
3514 : 0 : int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
3515 : : const struct task_struct *tsk2)
3516 : : {
3517 : 0 : return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
3518 : : }
3519 : :
3520 : : /**
3521 : : * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
3522 : : *
3523 : : * Description: Prints current's name, cpuset name, and cached copy of its
3524 : : * mems_allowed to the kernel log.
3525 : : */
3526 : 0 : void cpuset_print_current_mems_allowed(void)
3527 : : {
3528 : : struct cgroup *cgrp;
3529 : :
3530 : : rcu_read_lock();
3531 : :
3532 : 0 : cgrp = task_cs(current)->css.cgroup;
3533 : 0 : pr_cont(",cpuset=");
3534 : : pr_cont_cgroup_name(cgrp);
3535 : 0 : pr_cont(",mems_allowed=%*pbl",
3536 : : nodemask_pr_args(¤t->mems_allowed));
3537 : :
3538 : : rcu_read_unlock();
3539 : 0 : }
3540 : :
3541 : : /*
3542 : : * Collection of memory_pressure is suppressed unless
3543 : : * this flag is enabled by writing "1" to the special
3544 : : * cpuset file 'memory_pressure_enabled' in the root cpuset.
3545 : : */
3546 : :
3547 : : int cpuset_memory_pressure_enabled __read_mostly;
3548 : :
3549 : : /**
3550 : : * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
3551 : : *
3552 : : * Keep a running average of the rate of synchronous (direct)
3553 : : * page reclaim efforts initiated by tasks in each cpuset.
3554 : : *
3555 : : * This represents the rate at which some task in the cpuset
3556 : : * ran low on memory on all nodes it was allowed to use, and
3557 : : * had to enter the kernels page reclaim code in an effort to
3558 : : * create more free memory by tossing clean pages or swapping
3559 : : * or writing dirty pages.
3560 : : *
3561 : : * Display to user space in the per-cpuset read-only file
3562 : : * "memory_pressure". Value displayed is an integer
3563 : : * representing the recent rate of entry into the synchronous
3564 : : * (direct) page reclaim by any task attached to the cpuset.
3565 : : **/
3566 : :
3567 : 0 : void __cpuset_memory_pressure_bump(void)
3568 : : {
3569 : : rcu_read_lock();
3570 : 0 : fmeter_markevent(&task_cs(current)->fmeter);
3571 : : rcu_read_unlock();
3572 : 0 : }
3573 : :
3574 : : #ifdef CONFIG_PROC_PID_CPUSET
3575 : : /*
3576 : : * proc_cpuset_show()
3577 : : * - Print tasks cpuset path into seq_file.
3578 : : * - Used for /proc/<pid>/cpuset.
3579 : : * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
3580 : : * doesn't really matter if tsk->cpuset changes after we read it,
3581 : : * and we take cpuset_mutex, keeping cpuset_attach() from changing it
3582 : : * anyway.
3583 : : */
3584 : 0 : int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
3585 : : struct pid *pid, struct task_struct *tsk)
3586 : : {
3587 : : char *buf;
3588 : : struct cgroup_subsys_state *css;
3589 : : int retval;
3590 : :
3591 : : retval = -ENOMEM;
3592 : : buf = kmalloc(PATH_MAX, GFP_KERNEL);
3593 [ # # ]: 0 : if (!buf)
3594 : : goto out;
3595 : :
3596 : 0 : css = task_get_css(tsk, cpuset_cgrp_id);
3597 : 0 : retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
3598 : 0 : current->nsproxy->cgroup_ns);
3599 : : css_put(css);
3600 [ # # ]: 0 : if (retval >= PATH_MAX)
3601 : : retval = -ENAMETOOLONG;
3602 [ # # ]: 0 : if (retval < 0)
3603 : : goto out_free;
3604 : 0 : seq_puts(m, buf);
3605 : 0 : seq_putc(m, '\n');
3606 : : retval = 0;
3607 : : out_free:
3608 : 0 : kfree(buf);
3609 : : out:
3610 : 0 : return retval;
3611 : : }
3612 : : #endif /* CONFIG_PROC_PID_CPUSET */
3613 : :
3614 : : /* Display task mems_allowed in /proc/<pid>/status file. */
3615 : 41162 : void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
3616 : : {
3617 : 41162 : seq_printf(m, "Mems_allowed:\t%*pb\n",
3618 : 41162 : nodemask_pr_args(&task->mems_allowed));
3619 : 41162 : seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
3620 : : nodemask_pr_args(&task->mems_allowed));
3621 : 41162 : }
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