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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/namei.h> | |
43 | #include <linux/pagemap.h> | |
44 | #include <linux/proc_fs.h> | |
45 | #include <linux/rcupdate.h> | |
46 | #include <linux/sched.h> | |
47 | #include <linux/seq_file.h> | |
48 | #include <linux/security.h> | |
49 | #include <linux/slab.h> | |
50 | #include <linux/spinlock.h> | |
51 | #include <linux/stat.h> | |
52 | #include <linux/string.h> | |
53 | #include <linux/time.h> | |
54 | #include <linux/time64.h> | |
55 | #include <linux/backing-dev.h> | |
56 | #include <linux/sort.h> | |
57 | ||
58 | #include <linux/uaccess.h> | |
59 | #include <linux/atomic.h> | |
60 | #include <linux/mutex.h> | |
61 | #include <linux/cgroup.h> | |
62 | #include <linux/wait.h> | |
63 | ||
64 | DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key); | |
65 | ||
66 | /* See "Frequency meter" comments, below. */ | |
67 | ||
68 | struct fmeter { | |
69 | int cnt; /* unprocessed events count */ | |
70 | int val; /* most recent output value */ | |
71 | time64_t time; /* clock (secs) when val computed */ | |
72 | spinlock_t lock; /* guards read or write of above */ | |
73 | }; | |
74 | ||
75 | struct cpuset { | |
76 | struct cgroup_subsys_state css; | |
77 | ||
78 | unsigned long flags; /* "unsigned long" so bitops work */ | |
79 | ||
80 | /* | |
81 | * On default hierarchy: | |
82 | * | |
83 | * The user-configured masks can only be changed by writing to | |
84 | * cpuset.cpus and cpuset.mems, and won't be limited by the | |
85 | * parent masks. | |
86 | * | |
87 | * The effective masks is the real masks that apply to the tasks | |
88 | * in the cpuset. They may be changed if the configured masks are | |
89 | * changed or hotplug happens. | |
90 | * | |
91 | * effective_mask == configured_mask & parent's effective_mask, | |
92 | * and if it ends up empty, it will inherit the parent's mask. | |
93 | * | |
94 | * | |
95 | * On legacy hierachy: | |
96 | * | |
97 | * The user-configured masks are always the same with effective masks. | |
98 | */ | |
99 | ||
100 | /* user-configured CPUs and Memory Nodes allow to tasks */ | |
101 | cpumask_var_t cpus_allowed; | |
102 | nodemask_t mems_allowed; | |
103 | ||
104 | /* effective CPUs and Memory Nodes allow to tasks */ | |
105 | cpumask_var_t effective_cpus; | |
106 | nodemask_t effective_mems; | |
107 | ||
108 | /* | |
109 | * This is old Memory Nodes tasks took on. | |
110 | * | |
111 | * - top_cpuset.old_mems_allowed is initialized to mems_allowed. | |
112 | * - A new cpuset's old_mems_allowed is initialized when some | |
113 | * task is moved into it. | |
114 | * - old_mems_allowed is used in cpuset_migrate_mm() when we change | |
115 | * cpuset.mems_allowed and have tasks' nodemask updated, and | |
116 | * then old_mems_allowed is updated to mems_allowed. | |
117 | */ | |
118 | nodemask_t old_mems_allowed; | |
119 | ||
120 | struct fmeter fmeter; /* memory_pressure filter */ | |
121 | ||
122 | /* | |
123 | * Tasks are being attached to this cpuset. Used to prevent | |
124 | * zeroing cpus/mems_allowed between ->can_attach() and ->attach(). | |
125 | */ | |
126 | int attach_in_progress; | |
127 | ||
128 | /* partition number for rebuild_sched_domains() */ | |
129 | int pn; | |
130 | ||
131 | /* for custom sched domain */ | |
132 | int relax_domain_level; | |
133 | }; | |
134 | ||
135 | static inline struct cpuset *css_cs(struct cgroup_subsys_state *css) | |
136 | { | |
137 | return css ? container_of(css, struct cpuset, css) : NULL; | |
138 | } | |
139 | ||
140 | /* Retrieve the cpuset for a task */ | |
141 | static inline struct cpuset *task_cs(struct task_struct *task) | |
142 | { | |
143 | return css_cs(task_css(task, cpuset_cgrp_id)); | |
144 | } | |
145 | ||
146 | static inline struct cpuset *parent_cs(struct cpuset *cs) | |
147 | { | |
148 | return css_cs(cs->css.parent); | |
149 | } | |
150 | ||
151 | #ifdef CONFIG_NUMA | |
152 | static inline bool task_has_mempolicy(struct task_struct *task) | |
153 | { | |
154 | return task->mempolicy; | |
155 | } | |
156 | #else | |
157 | static inline bool task_has_mempolicy(struct task_struct *task) | |
158 | { | |
159 | return false; | |
160 | } | |
161 | #endif | |
162 | ||
163 | ||
164 | /* bits in struct cpuset flags field */ | |
165 | typedef enum { | |
166 | CS_ONLINE, | |
167 | CS_CPU_EXCLUSIVE, | |
168 | CS_MEM_EXCLUSIVE, | |
169 | CS_MEM_HARDWALL, | |
170 | CS_MEMORY_MIGRATE, | |
171 | CS_SCHED_LOAD_BALANCE, | |
172 | CS_SPREAD_PAGE, | |
173 | CS_SPREAD_SLAB, | |
174 | } cpuset_flagbits_t; | |
175 | ||
176 | /* convenient tests for these bits */ | |
177 | static inline bool is_cpuset_online(const struct cpuset *cs) | |
178 | { | |
179 | return test_bit(CS_ONLINE, &cs->flags); | |
180 | } | |
181 | ||
182 | static inline int is_cpu_exclusive(const struct cpuset *cs) | |
183 | { | |
184 | return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); | |
185 | } | |
186 | ||
187 | static inline int is_mem_exclusive(const struct cpuset *cs) | |
188 | { | |
189 | return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); | |
190 | } | |
191 | ||
192 | static inline int is_mem_hardwall(const struct cpuset *cs) | |
193 | { | |
194 | return test_bit(CS_MEM_HARDWALL, &cs->flags); | |
195 | } | |
196 | ||
197 | static inline int is_sched_load_balance(const struct cpuset *cs) | |
198 | { | |
199 | return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); | |
200 | } | |
201 | ||
202 | static inline int is_memory_migrate(const struct cpuset *cs) | |
203 | { | |
204 | return test_bit(CS_MEMORY_MIGRATE, &cs->flags); | |
205 | } | |
206 | ||
207 | static inline int is_spread_page(const struct cpuset *cs) | |
208 | { | |
209 | return test_bit(CS_SPREAD_PAGE, &cs->flags); | |
210 | } | |
211 | ||
212 | static inline int is_spread_slab(const struct cpuset *cs) | |
213 | { | |
214 | return test_bit(CS_SPREAD_SLAB, &cs->flags); | |
215 | } | |
216 | ||
217 | static struct cpuset top_cpuset = { | |
218 | .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | | |
219 | (1 << CS_MEM_EXCLUSIVE)), | |
220 | }; | |
221 | ||
222 | /** | |
223 | * cpuset_for_each_child - traverse online children of a cpuset | |
224 | * @child_cs: loop cursor pointing to the current child | |
225 | * @pos_css: used for iteration | |
226 | * @parent_cs: target cpuset to walk children of | |
227 | * | |
228 | * Walk @child_cs through the online children of @parent_cs. Must be used | |
229 | * with RCU read locked. | |
230 | */ | |
231 | #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \ | |
232 | css_for_each_child((pos_css), &(parent_cs)->css) \ | |
233 | if (is_cpuset_online(((child_cs) = css_cs((pos_css))))) | |
234 | ||
235 | /** | |
236 | * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants | |
237 | * @des_cs: loop cursor pointing to the current descendant | |
238 | * @pos_css: used for iteration | |
239 | * @root_cs: target cpuset to walk ancestor of | |
240 | * | |
241 | * Walk @des_cs through the online descendants of @root_cs. Must be used | |
242 | * with RCU read locked. The caller may modify @pos_css by calling | |
243 | * css_rightmost_descendant() to skip subtree. @root_cs is included in the | |
244 | * iteration and the first node to be visited. | |
245 | */ | |
246 | #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \ | |
247 | css_for_each_descendant_pre((pos_css), &(root_cs)->css) \ | |
248 | if (is_cpuset_online(((des_cs) = css_cs((pos_css))))) | |
249 | ||
250 | /* | |
251 | * There are two global locks guarding cpuset structures - cpuset_mutex and | |
252 | * callback_lock. We also require taking task_lock() when dereferencing a | |
253 | * task's cpuset pointer. See "The task_lock() exception", at the end of this | |
254 | * comment. | |
255 | * | |
256 | * A task must hold both locks to modify cpusets. If a task holds | |
257 | * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it | |
258 | * is the only task able to also acquire callback_lock and be able to | |
259 | * modify cpusets. It can perform various checks on the cpuset structure | |
260 | * first, knowing nothing will change. It can also allocate memory while | |
261 | * just holding cpuset_mutex. While it is performing these checks, various | |
262 | * callback routines can briefly acquire callback_lock to query cpusets. | |
263 | * Once it is ready to make the changes, it takes callback_lock, blocking | |
264 | * everyone else. | |
265 | * | |
266 | * Calls to the kernel memory allocator can not be made while holding | |
267 | * callback_lock, as that would risk double tripping on callback_lock | |
268 | * from one of the callbacks into the cpuset code from within | |
269 | * __alloc_pages(). | |
270 | * | |
271 | * If a task is only holding callback_lock, then it has read-only | |
272 | * access to cpusets. | |
273 | * | |
274 | * Now, the task_struct fields mems_allowed and mempolicy may be changed | |
275 | * by other task, we use alloc_lock in the task_struct fields to protect | |
276 | * them. | |
277 | * | |
278 | * The cpuset_common_file_read() handlers only hold callback_lock across | |
279 | * small pieces of code, such as when reading out possibly multi-word | |
280 | * cpumasks and nodemasks. | |
281 | * | |
282 | * Accessing a task's cpuset should be done in accordance with the | |
283 | * guidelines for accessing subsystem state in kernel/cgroup.c | |
284 | */ | |
285 | ||
286 | static DEFINE_MUTEX(cpuset_mutex); | |
287 | static DEFINE_SPINLOCK(callback_lock); | |
288 | ||
289 | static struct workqueue_struct *cpuset_migrate_mm_wq; | |
290 | ||
291 | /* | |
292 | * CPU / memory hotplug is handled asynchronously. | |
293 | */ | |
294 | static void cpuset_hotplug_workfn(struct work_struct *work); | |
295 | static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); | |
296 | ||
297 | static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); | |
298 | ||
299 | /* | |
300 | * This is ugly, but preserves the userspace API for existing cpuset | |
301 | * users. If someone tries to mount the "cpuset" filesystem, we | |
302 | * silently switch it to mount "cgroup" instead | |
303 | */ | |
304 | static struct dentry *cpuset_mount(struct file_system_type *fs_type, | |
305 | int flags, const char *unused_dev_name, void *data) | |
306 | { | |
307 | struct file_system_type *cgroup_fs = get_fs_type("cgroup"); | |
308 | struct dentry *ret = ERR_PTR(-ENODEV); | |
309 | if (cgroup_fs) { | |
310 | char mountopts[] = | |
311 | "cpuset,noprefix," | |
312 | "release_agent=/sbin/cpuset_release_agent"; | |
313 | ret = cgroup_fs->mount(cgroup_fs, flags, | |
314 | unused_dev_name, mountopts); | |
315 | put_filesystem(cgroup_fs); | |
316 | } | |
317 | return ret; | |
318 | } | |
319 | ||
320 | static struct file_system_type cpuset_fs_type = { | |
321 | .name = "cpuset", | |
322 | .mount = cpuset_mount, | |
323 | }; | |
324 | ||
325 | /* | |
326 | * Return in pmask the portion of a cpusets's cpus_allowed that | |
327 | * are online. If none are online, walk up the cpuset hierarchy | |
328 | * until we find one that does have some online cpus. | |
329 | * | |
330 | * One way or another, we guarantee to return some non-empty subset | |
331 | * of cpu_online_mask. | |
332 | * | |
333 | * Call with callback_lock or cpuset_mutex held. | |
334 | */ | |
335 | static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) | |
336 | { | |
337 | while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) { | |
338 | cs = parent_cs(cs); | |
339 | if (unlikely(!cs)) { | |
340 | /* | |
341 | * The top cpuset doesn't have any online cpu as a | |
342 | * consequence of a race between cpuset_hotplug_work | |
343 | * and cpu hotplug notifier. But we know the top | |
344 | * cpuset's effective_cpus is on its way to to be | |
345 | * identical to cpu_online_mask. | |
346 | */ | |
347 | cpumask_copy(pmask, cpu_online_mask); | |
348 | return; | |
349 | } | |
350 | } | |
351 | cpumask_and(pmask, cs->effective_cpus, cpu_online_mask); | |
352 | } | |
353 | ||
354 | /* | |
355 | * Return in *pmask the portion of a cpusets's mems_allowed that | |
356 | * are online, with memory. If none are online with memory, walk | |
357 | * up the cpuset hierarchy until we find one that does have some | |
358 | * online mems. The top cpuset always has some mems online. | |
359 | * | |
360 | * One way or another, we guarantee to return some non-empty subset | |
361 | * of node_states[N_MEMORY]. | |
362 | * | |
363 | * Call with callback_lock or cpuset_mutex held. | |
364 | */ | |
365 | static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) | |
366 | { | |
367 | while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY])) | |
368 | cs = parent_cs(cs); | |
369 | nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]); | |
370 | } | |
371 | ||
372 | /* | |
373 | * update task's spread flag if cpuset's page/slab spread flag is set | |
374 | * | |
375 | * Call with callback_lock or cpuset_mutex held. | |
376 | */ | |
377 | static void cpuset_update_task_spread_flag(struct cpuset *cs, | |
378 | struct task_struct *tsk) | |
379 | { | |
380 | if (is_spread_page(cs)) | |
381 | task_set_spread_page(tsk); | |
382 | else | |
383 | task_clear_spread_page(tsk); | |
384 | ||
385 | if (is_spread_slab(cs)) | |
386 | task_set_spread_slab(tsk); | |
387 | else | |
388 | task_clear_spread_slab(tsk); | |
389 | } | |
390 | ||
391 | /* | |
392 | * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? | |
393 | * | |
394 | * One cpuset is a subset of another if all its allowed CPUs and | |
395 | * Memory Nodes are a subset of the other, and its exclusive flags | |
396 | * are only set if the other's are set. Call holding cpuset_mutex. | |
397 | */ | |
398 | ||
399 | static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) | |
400 | { | |
401 | return cpumask_subset(p->cpus_allowed, q->cpus_allowed) && | |
402 | nodes_subset(p->mems_allowed, q->mems_allowed) && | |
403 | is_cpu_exclusive(p) <= is_cpu_exclusive(q) && | |
404 | is_mem_exclusive(p) <= is_mem_exclusive(q); | |
405 | } | |
406 | ||
407 | /** | |
408 | * alloc_trial_cpuset - allocate a trial cpuset | |
409 | * @cs: the cpuset that the trial cpuset duplicates | |
410 | */ | |
411 | static struct cpuset *alloc_trial_cpuset(struct cpuset *cs) | |
412 | { | |
413 | struct cpuset *trial; | |
414 | ||
415 | trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); | |
416 | if (!trial) | |
417 | return NULL; | |
418 | ||
419 | if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) | |
420 | goto free_cs; | |
421 | if (!alloc_cpumask_var(&trial->effective_cpus, GFP_KERNEL)) | |
422 | goto free_cpus; | |
423 | ||
424 | cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); | |
425 | cpumask_copy(trial->effective_cpus, cs->effective_cpus); | |
426 | return trial; | |
427 | ||
428 | free_cpus: | |
429 | free_cpumask_var(trial->cpus_allowed); | |
430 | free_cs: | |
431 | kfree(trial); | |
432 | return NULL; | |
433 | } | |
434 | ||
435 | /** | |
436 | * free_trial_cpuset - free the trial cpuset | |
437 | * @trial: the trial cpuset to be freed | |
438 | */ | |
439 | static void free_trial_cpuset(struct cpuset *trial) | |
440 | { | |
441 | free_cpumask_var(trial->effective_cpus); | |
442 | free_cpumask_var(trial->cpus_allowed); | |
443 | kfree(trial); | |
444 | } | |
445 | ||
446 | /* | |
447 | * validate_change() - Used to validate that any proposed cpuset change | |
448 | * follows the structural rules for cpusets. | |
449 | * | |
450 | * If we replaced the flag and mask values of the current cpuset | |
451 | * (cur) with those values in the trial cpuset (trial), would | |
452 | * our various subset and exclusive rules still be valid? Presumes | |
453 | * cpuset_mutex held. | |
454 | * | |
455 | * 'cur' is the address of an actual, in-use cpuset. Operations | |
456 | * such as list traversal that depend on the actual address of the | |
457 | * cpuset in the list must use cur below, not trial. | |
458 | * | |
459 | * 'trial' is the address of bulk structure copy of cur, with | |
460 | * perhaps one or more of the fields cpus_allowed, mems_allowed, | |
461 | * or flags changed to new, trial values. | |
462 | * | |
463 | * Return 0 if valid, -errno if not. | |
464 | */ | |
465 | ||
466 | static int validate_change(struct cpuset *cur, struct cpuset *trial) | |
467 | { | |
468 | struct cgroup_subsys_state *css; | |
469 | struct cpuset *c, *par; | |
470 | int ret; | |
471 | ||
472 | rcu_read_lock(); | |
473 | ||
474 | /* Each of our child cpusets must be a subset of us */ | |
475 | ret = -EBUSY; | |
476 | cpuset_for_each_child(c, css, cur) | |
477 | if (!is_cpuset_subset(c, trial)) | |
478 | goto out; | |
479 | ||
480 | /* Remaining checks don't apply to root cpuset */ | |
481 | ret = 0; | |
482 | if (cur == &top_cpuset) | |
483 | goto out; | |
484 | ||
485 | par = parent_cs(cur); | |
486 | ||
487 | /* On legacy hiearchy, we must be a subset of our parent cpuset. */ | |
488 | ret = -EACCES; | |
489 | if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
490 | !is_cpuset_subset(trial, par)) | |
491 | goto out; | |
492 | ||
493 | /* | |
494 | * If either I or some sibling (!= me) is exclusive, we can't | |
495 | * overlap | |
496 | */ | |
497 | ret = -EINVAL; | |
498 | cpuset_for_each_child(c, css, par) { | |
499 | if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && | |
500 | c != cur && | |
501 | cpumask_intersects(trial->cpus_allowed, c->cpus_allowed)) | |
502 | goto out; | |
503 | if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && | |
504 | c != cur && | |
505 | nodes_intersects(trial->mems_allowed, c->mems_allowed)) | |
506 | goto out; | |
507 | } | |
508 | ||
509 | /* | |
510 | * Cpusets with tasks - existing or newly being attached - can't | |
511 | * be changed to have empty cpus_allowed or mems_allowed. | |
512 | */ | |
513 | ret = -ENOSPC; | |
514 | if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) { | |
515 | if (!cpumask_empty(cur->cpus_allowed) && | |
516 | cpumask_empty(trial->cpus_allowed)) | |
517 | goto out; | |
518 | if (!nodes_empty(cur->mems_allowed) && | |
519 | nodes_empty(trial->mems_allowed)) | |
520 | goto out; | |
521 | } | |
522 | ||
523 | /* | |
524 | * We can't shrink if we won't have enough room for SCHED_DEADLINE | |
525 | * tasks. | |
526 | */ | |
527 | ret = -EBUSY; | |
528 | if (is_cpu_exclusive(cur) && | |
529 | !cpuset_cpumask_can_shrink(cur->cpus_allowed, | |
530 | trial->cpus_allowed)) | |
531 | goto out; | |
532 | ||
533 | ret = 0; | |
534 | out: | |
535 | rcu_read_unlock(); | |
536 | return ret; | |
537 | } | |
538 | ||
539 | #ifdef CONFIG_SMP | |
540 | /* | |
541 | * Helper routine for generate_sched_domains(). | |
542 | * Do cpusets a, b have overlapping effective cpus_allowed masks? | |
543 | */ | |
544 | static int cpusets_overlap(struct cpuset *a, struct cpuset *b) | |
545 | { | |
546 | return cpumask_intersects(a->effective_cpus, b->effective_cpus); | |
547 | } | |
548 | ||
549 | static void | |
550 | update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) | |
551 | { | |
552 | if (dattr->relax_domain_level < c->relax_domain_level) | |
553 | dattr->relax_domain_level = c->relax_domain_level; | |
554 | return; | |
555 | } | |
556 | ||
557 | static void update_domain_attr_tree(struct sched_domain_attr *dattr, | |
558 | struct cpuset *root_cs) | |
559 | { | |
560 | struct cpuset *cp; | |
561 | struct cgroup_subsys_state *pos_css; | |
562 | ||
563 | rcu_read_lock(); | |
564 | cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { | |
565 | /* skip the whole subtree if @cp doesn't have any CPU */ | |
566 | if (cpumask_empty(cp->cpus_allowed)) { | |
567 | pos_css = css_rightmost_descendant(pos_css); | |
568 | continue; | |
569 | } | |
570 | ||
571 | if (is_sched_load_balance(cp)) | |
572 | update_domain_attr(dattr, cp); | |
573 | } | |
574 | rcu_read_unlock(); | |
575 | } | |
576 | ||
577 | /* | |
578 | * generate_sched_domains() | |
579 | * | |
580 | * This function builds a partial partition of the systems CPUs | |
581 | * A 'partial partition' is a set of non-overlapping subsets whose | |
582 | * union is a subset of that set. | |
583 | * The output of this function needs to be passed to kernel/sched/core.c | |
584 | * partition_sched_domains() routine, which will rebuild the scheduler's | |
585 | * load balancing domains (sched domains) as specified by that partial | |
586 | * partition. | |
587 | * | |
588 | * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt | |
589 | * for a background explanation of this. | |
590 | * | |
591 | * Does not return errors, on the theory that the callers of this | |
592 | * routine would rather not worry about failures to rebuild sched | |
593 | * domains when operating in the severe memory shortage situations | |
594 | * that could cause allocation failures below. | |
595 | * | |
596 | * Must be called with cpuset_mutex held. | |
597 | * | |
598 | * The three key local variables below are: | |
599 | * q - a linked-list queue of cpuset pointers, used to implement a | |
600 | * top-down scan of all cpusets. This scan loads a pointer | |
601 | * to each cpuset marked is_sched_load_balance into the | |
602 | * array 'csa'. For our purposes, rebuilding the schedulers | |
603 | * sched domains, we can ignore !is_sched_load_balance cpusets. | |
604 | * csa - (for CpuSet Array) Array of pointers to all the cpusets | |
605 | * that need to be load balanced, for convenient iterative | |
606 | * access by the subsequent code that finds the best partition, | |
607 | * i.e the set of domains (subsets) of CPUs such that the | |
608 | * cpus_allowed of every cpuset marked is_sched_load_balance | |
609 | * is a subset of one of these domains, while there are as | |
610 | * many such domains as possible, each as small as possible. | |
611 | * doms - Conversion of 'csa' to an array of cpumasks, for passing to | |
612 | * the kernel/sched/core.c routine partition_sched_domains() in a | |
613 | * convenient format, that can be easily compared to the prior | |
614 | * value to determine what partition elements (sched domains) | |
615 | * were changed (added or removed.) | |
616 | * | |
617 | * Finding the best partition (set of domains): | |
618 | * The triple nested loops below over i, j, k scan over the | |
619 | * load balanced cpusets (using the array of cpuset pointers in | |
620 | * csa[]) looking for pairs of cpusets that have overlapping | |
621 | * cpus_allowed, but which don't have the same 'pn' partition | |
622 | * number and gives them in the same partition number. It keeps | |
623 | * looping on the 'restart' label until it can no longer find | |
624 | * any such pairs. | |
625 | * | |
626 | * The union of the cpus_allowed masks from the set of | |
627 | * all cpusets having the same 'pn' value then form the one | |
628 | * element of the partition (one sched domain) to be passed to | |
629 | * partition_sched_domains(). | |
630 | */ | |
631 | static int generate_sched_domains(cpumask_var_t **domains, | |
632 | struct sched_domain_attr **attributes) | |
633 | { | |
634 | struct cpuset *cp; /* scans q */ | |
635 | struct cpuset **csa; /* array of all cpuset ptrs */ | |
636 | int csn; /* how many cpuset ptrs in csa so far */ | |
637 | int i, j, k; /* indices for partition finding loops */ | |
638 | cpumask_var_t *doms; /* resulting partition; i.e. sched domains */ | |
639 | cpumask_var_t non_isolated_cpus; /* load balanced CPUs */ | |
640 | struct sched_domain_attr *dattr; /* attributes for custom domains */ | |
641 | int ndoms = 0; /* number of sched domains in result */ | |
642 | int nslot; /* next empty doms[] struct cpumask slot */ | |
643 | struct cgroup_subsys_state *pos_css; | |
644 | ||
645 | doms = NULL; | |
646 | dattr = NULL; | |
647 | csa = NULL; | |
648 | ||
649 | if (!alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL)) | |
650 | goto done; | |
651 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); | |
652 | ||
653 | /* Special case for the 99% of systems with one, full, sched domain */ | |
654 | if (is_sched_load_balance(&top_cpuset)) { | |
655 | ndoms = 1; | |
656 | doms = alloc_sched_domains(ndoms); | |
657 | if (!doms) | |
658 | goto done; | |
659 | ||
660 | dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); | |
661 | if (dattr) { | |
662 | *dattr = SD_ATTR_INIT; | |
663 | update_domain_attr_tree(dattr, &top_cpuset); | |
664 | } | |
665 | cpumask_and(doms[0], top_cpuset.effective_cpus, | |
666 | non_isolated_cpus); | |
667 | ||
668 | goto done; | |
669 | } | |
670 | ||
671 | csa = kmalloc(nr_cpusets() * sizeof(cp), GFP_KERNEL); | |
672 | if (!csa) | |
673 | goto done; | |
674 | csn = 0; | |
675 | ||
676 | rcu_read_lock(); | |
677 | cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) { | |
678 | if (cp == &top_cpuset) | |
679 | continue; | |
680 | /* | |
681 | * Continue traversing beyond @cp iff @cp has some CPUs and | |
682 | * isn't load balancing. The former is obvious. The | |
683 | * latter: All child cpusets contain a subset of the | |
684 | * parent's cpus, so just skip them, and then we call | |
685 | * update_domain_attr_tree() to calc relax_domain_level of | |
686 | * the corresponding sched domain. | |
687 | */ | |
688 | if (!cpumask_empty(cp->cpus_allowed) && | |
689 | !(is_sched_load_balance(cp) && | |
690 | cpumask_intersects(cp->cpus_allowed, non_isolated_cpus))) | |
691 | continue; | |
692 | ||
693 | if (is_sched_load_balance(cp)) | |
694 | csa[csn++] = cp; | |
695 | ||
696 | /* skip @cp's subtree */ | |
697 | pos_css = css_rightmost_descendant(pos_css); | |
698 | } | |
699 | rcu_read_unlock(); | |
700 | ||
701 | for (i = 0; i < csn; i++) | |
702 | csa[i]->pn = i; | |
703 | ndoms = csn; | |
704 | ||
705 | restart: | |
706 | /* Find the best partition (set of sched domains) */ | |
707 | for (i = 0; i < csn; i++) { | |
708 | struct cpuset *a = csa[i]; | |
709 | int apn = a->pn; | |
710 | ||
711 | for (j = 0; j < csn; j++) { | |
712 | struct cpuset *b = csa[j]; | |
713 | int bpn = b->pn; | |
714 | ||
715 | if (apn != bpn && cpusets_overlap(a, b)) { | |
716 | for (k = 0; k < csn; k++) { | |
717 | struct cpuset *c = csa[k]; | |
718 | ||
719 | if (c->pn == bpn) | |
720 | c->pn = apn; | |
721 | } | |
722 | ndoms--; /* one less element */ | |
723 | goto restart; | |
724 | } | |
725 | } | |
726 | } | |
727 | ||
728 | /* | |
729 | * Now we know how many domains to create. | |
730 | * Convert <csn, csa> to <ndoms, doms> and populate cpu masks. | |
731 | */ | |
732 | doms = alloc_sched_domains(ndoms); | |
733 | if (!doms) | |
734 | goto done; | |
735 | ||
736 | /* | |
737 | * The rest of the code, including the scheduler, can deal with | |
738 | * dattr==NULL case. No need to abort if alloc fails. | |
739 | */ | |
740 | dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL); | |
741 | ||
742 | for (nslot = 0, i = 0; i < csn; i++) { | |
743 | struct cpuset *a = csa[i]; | |
744 | struct cpumask *dp; | |
745 | int apn = a->pn; | |
746 | ||
747 | if (apn < 0) { | |
748 | /* Skip completed partitions */ | |
749 | continue; | |
750 | } | |
751 | ||
752 | dp = doms[nslot]; | |
753 | ||
754 | if (nslot == ndoms) { | |
755 | static int warnings = 10; | |
756 | if (warnings) { | |
757 | pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n", | |
758 | nslot, ndoms, csn, i, apn); | |
759 | warnings--; | |
760 | } | |
761 | continue; | |
762 | } | |
763 | ||
764 | cpumask_clear(dp); | |
765 | if (dattr) | |
766 | *(dattr + nslot) = SD_ATTR_INIT; | |
767 | for (j = i; j < csn; j++) { | |
768 | struct cpuset *b = csa[j]; | |
769 | ||
770 | if (apn == b->pn) { | |
771 | cpumask_or(dp, dp, b->effective_cpus); | |
772 | cpumask_and(dp, dp, non_isolated_cpus); | |
773 | if (dattr) | |
774 | update_domain_attr_tree(dattr + nslot, b); | |
775 | ||
776 | /* Done with this partition */ | |
777 | b->pn = -1; | |
778 | } | |
779 | } | |
780 | nslot++; | |
781 | } | |
782 | BUG_ON(nslot != ndoms); | |
783 | ||
784 | done: | |
785 | free_cpumask_var(non_isolated_cpus); | |
786 | kfree(csa); | |
787 | ||
788 | /* | |
789 | * Fallback to the default domain if kmalloc() failed. | |
790 | * See comments in partition_sched_domains(). | |
791 | */ | |
792 | if (doms == NULL) | |
793 | ndoms = 1; | |
794 | ||
795 | *domains = doms; | |
796 | *attributes = dattr; | |
797 | return ndoms; | |
798 | } | |
799 | ||
800 | /* | |
801 | * Rebuild scheduler domains. | |
802 | * | |
803 | * If the flag 'sched_load_balance' of any cpuset with non-empty | |
804 | * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset | |
805 | * which has that flag enabled, or if any cpuset with a non-empty | |
806 | * 'cpus' is removed, then call this routine to rebuild the | |
807 | * scheduler's dynamic sched domains. | |
808 | * | |
809 | * Call with cpuset_mutex held. Takes get_online_cpus(). | |
810 | */ | |
811 | static void rebuild_sched_domains_locked(void) | |
812 | { | |
813 | struct sched_domain_attr *attr; | |
814 | cpumask_var_t *doms; | |
815 | int ndoms; | |
816 | ||
817 | lockdep_assert_held(&cpuset_mutex); | |
818 | get_online_cpus(); | |
819 | ||
820 | /* | |
821 | * We have raced with CPU hotplug. Don't do anything to avoid | |
822 | * passing doms with offlined cpu to partition_sched_domains(). | |
823 | * Anyways, hotplug work item will rebuild sched domains. | |
824 | */ | |
825 | if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) | |
826 | goto out; | |
827 | ||
828 | /* Generate domain masks and attrs */ | |
829 | ndoms = generate_sched_domains(&doms, &attr); | |
830 | ||
831 | /* Have scheduler rebuild the domains */ | |
832 | partition_sched_domains(ndoms, doms, attr); | |
833 | out: | |
834 | put_online_cpus(); | |
835 | } | |
836 | #else /* !CONFIG_SMP */ | |
837 | static void rebuild_sched_domains_locked(void) | |
838 | { | |
839 | } | |
840 | #endif /* CONFIG_SMP */ | |
841 | ||
842 | void rebuild_sched_domains(void) | |
843 | { | |
844 | mutex_lock(&cpuset_mutex); | |
845 | rebuild_sched_domains_locked(); | |
846 | mutex_unlock(&cpuset_mutex); | |
847 | } | |
848 | ||
849 | /** | |
850 | * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. | |
851 | * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed | |
852 | * | |
853 | * Iterate through each task of @cs updating its cpus_allowed to the | |
854 | * effective cpuset's. As this function is called with cpuset_mutex held, | |
855 | * cpuset membership stays stable. | |
856 | */ | |
857 | static void update_tasks_cpumask(struct cpuset *cs) | |
858 | { | |
859 | struct css_task_iter it; | |
860 | struct task_struct *task; | |
861 | ||
862 | css_task_iter_start(&cs->css, &it); | |
863 | while ((task = css_task_iter_next(&it))) | |
864 | set_cpus_allowed_ptr(task, cs->effective_cpus); | |
865 | css_task_iter_end(&it); | |
866 | } | |
867 | ||
868 | /* | |
869 | * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree | |
870 | * @cs: the cpuset to consider | |
871 | * @new_cpus: temp variable for calculating new effective_cpus | |
872 | * | |
873 | * When congifured cpumask is changed, the effective cpumasks of this cpuset | |
874 | * and all its descendants need to be updated. | |
875 | * | |
876 | * On legacy hierachy, effective_cpus will be the same with cpu_allowed. | |
877 | * | |
878 | * Called with cpuset_mutex held | |
879 | */ | |
880 | static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus) | |
881 | { | |
882 | struct cpuset *cp; | |
883 | struct cgroup_subsys_state *pos_css; | |
884 | bool need_rebuild_sched_domains = false; | |
885 | ||
886 | rcu_read_lock(); | |
887 | cpuset_for_each_descendant_pre(cp, pos_css, cs) { | |
888 | struct cpuset *parent = parent_cs(cp); | |
889 | ||
890 | cpumask_and(new_cpus, cp->cpus_allowed, parent->effective_cpus); | |
891 | ||
892 | /* | |
893 | * If it becomes empty, inherit the effective mask of the | |
894 | * parent, which is guaranteed to have some CPUs. | |
895 | */ | |
896 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
897 | cpumask_empty(new_cpus)) | |
898 | cpumask_copy(new_cpus, parent->effective_cpus); | |
899 | ||
900 | /* Skip the whole subtree if the cpumask remains the same. */ | |
901 | if (cpumask_equal(new_cpus, cp->effective_cpus)) { | |
902 | pos_css = css_rightmost_descendant(pos_css); | |
903 | continue; | |
904 | } | |
905 | ||
906 | if (!css_tryget_online(&cp->css)) | |
907 | continue; | |
908 | rcu_read_unlock(); | |
909 | ||
910 | spin_lock_irq(&callback_lock); | |
911 | cpumask_copy(cp->effective_cpus, new_cpus); | |
912 | spin_unlock_irq(&callback_lock); | |
913 | ||
914 | WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
915 | !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); | |
916 | ||
917 | update_tasks_cpumask(cp); | |
918 | ||
919 | /* | |
920 | * If the effective cpumask of any non-empty cpuset is changed, | |
921 | * we need to rebuild sched domains. | |
922 | */ | |
923 | if (!cpumask_empty(cp->cpus_allowed) && | |
924 | is_sched_load_balance(cp)) | |
925 | need_rebuild_sched_domains = true; | |
926 | ||
927 | rcu_read_lock(); | |
928 | css_put(&cp->css); | |
929 | } | |
930 | rcu_read_unlock(); | |
931 | ||
932 | if (need_rebuild_sched_domains) | |
933 | rebuild_sched_domains_locked(); | |
934 | } | |
935 | ||
936 | /** | |
937 | * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it | |
938 | * @cs: the cpuset to consider | |
939 | * @trialcs: trial cpuset | |
940 | * @buf: buffer of cpu numbers written to this cpuset | |
941 | */ | |
942 | static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, | |
943 | const char *buf) | |
944 | { | |
945 | int retval; | |
946 | ||
947 | /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ | |
948 | if (cs == &top_cpuset) | |
949 | return -EACCES; | |
950 | ||
951 | /* | |
952 | * An empty cpus_allowed is ok only if the cpuset has no tasks. | |
953 | * Since cpulist_parse() fails on an empty mask, we special case | |
954 | * that parsing. The validate_change() call ensures that cpusets | |
955 | * with tasks have cpus. | |
956 | */ | |
957 | if (!*buf) { | |
958 | cpumask_clear(trialcs->cpus_allowed); | |
959 | } else { | |
960 | retval = cpulist_parse(buf, trialcs->cpus_allowed); | |
961 | if (retval < 0) | |
962 | return retval; | |
963 | ||
964 | if (!cpumask_subset(trialcs->cpus_allowed, | |
965 | top_cpuset.cpus_allowed)) | |
966 | return -EINVAL; | |
967 | } | |
968 | ||
969 | /* Nothing to do if the cpus didn't change */ | |
970 | if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) | |
971 | return 0; | |
972 | ||
973 | retval = validate_change(cs, trialcs); | |
974 | if (retval < 0) | |
975 | return retval; | |
976 | ||
977 | spin_lock_irq(&callback_lock); | |
978 | cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); | |
979 | spin_unlock_irq(&callback_lock); | |
980 | ||
981 | /* use trialcs->cpus_allowed as a temp variable */ | |
982 | update_cpumasks_hier(cs, trialcs->cpus_allowed); | |
983 | return 0; | |
984 | } | |
985 | ||
986 | /* | |
987 | * Migrate memory region from one set of nodes to another. This is | |
988 | * performed asynchronously as it can be called from process migration path | |
989 | * holding locks involved in process management. All mm migrations are | |
990 | * performed in the queued order and can be waited for by flushing | |
991 | * cpuset_migrate_mm_wq. | |
992 | */ | |
993 | ||
994 | struct cpuset_migrate_mm_work { | |
995 | struct work_struct work; | |
996 | struct mm_struct *mm; | |
997 | nodemask_t from; | |
998 | nodemask_t to; | |
999 | }; | |
1000 | ||
1001 | static void cpuset_migrate_mm_workfn(struct work_struct *work) | |
1002 | { | |
1003 | struct cpuset_migrate_mm_work *mwork = | |
1004 | container_of(work, struct cpuset_migrate_mm_work, work); | |
1005 | ||
1006 | /* on a wq worker, no need to worry about %current's mems_allowed */ | |
1007 | do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL); | |
1008 | mmput(mwork->mm); | |
1009 | kfree(mwork); | |
1010 | } | |
1011 | ||
1012 | static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, | |
1013 | const nodemask_t *to) | |
1014 | { | |
1015 | struct cpuset_migrate_mm_work *mwork; | |
1016 | ||
1017 | mwork = kzalloc(sizeof(*mwork), GFP_KERNEL); | |
1018 | if (mwork) { | |
1019 | mwork->mm = mm; | |
1020 | mwork->from = *from; | |
1021 | mwork->to = *to; | |
1022 | INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn); | |
1023 | queue_work(cpuset_migrate_mm_wq, &mwork->work); | |
1024 | } else { | |
1025 | mmput(mm); | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | static void cpuset_post_attach(void) | |
1030 | { | |
1031 | flush_workqueue(cpuset_migrate_mm_wq); | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy | |
1036 | * @tsk: the task to change | |
1037 | * @newmems: new nodes that the task will be set | |
1038 | * | |
1039 | * In order to avoid seeing no nodes if the old and new nodes are disjoint, | |
1040 | * we structure updates as setting all new allowed nodes, then clearing newly | |
1041 | * disallowed ones. | |
1042 | */ | |
1043 | static void cpuset_change_task_nodemask(struct task_struct *tsk, | |
1044 | nodemask_t *newmems) | |
1045 | { | |
1046 | bool need_loop; | |
1047 | ||
1048 | task_lock(tsk); | |
1049 | /* | |
1050 | * Determine if a loop is necessary if another thread is doing | |
1051 | * read_mems_allowed_begin(). If at least one node remains unchanged and | |
1052 | * tsk does not have a mempolicy, then an empty nodemask will not be | |
1053 | * possible when mems_allowed is larger than a word. | |
1054 | */ | |
1055 | need_loop = task_has_mempolicy(tsk) || | |
1056 | !nodes_intersects(*newmems, tsk->mems_allowed); | |
1057 | ||
1058 | if (need_loop) { | |
1059 | local_irq_disable(); | |
1060 | write_seqcount_begin(&tsk->mems_allowed_seq); | |
1061 | } | |
1062 | ||
1063 | nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); | |
1064 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1); | |
1065 | ||
1066 | mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2); | |
1067 | tsk->mems_allowed = *newmems; | |
1068 | ||
1069 | if (need_loop) { | |
1070 | write_seqcount_end(&tsk->mems_allowed_seq); | |
1071 | local_irq_enable(); | |
1072 | } | |
1073 | ||
1074 | task_unlock(tsk); | |
1075 | } | |
1076 | ||
1077 | static void *cpuset_being_rebound; | |
1078 | ||
1079 | /** | |
1080 | * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. | |
1081 | * @cs: the cpuset in which each task's mems_allowed mask needs to be changed | |
1082 | * | |
1083 | * Iterate through each task of @cs updating its mems_allowed to the | |
1084 | * effective cpuset's. As this function is called with cpuset_mutex held, | |
1085 | * cpuset membership stays stable. | |
1086 | */ | |
1087 | static void update_tasks_nodemask(struct cpuset *cs) | |
1088 | { | |
1089 | static nodemask_t newmems; /* protected by cpuset_mutex */ | |
1090 | struct css_task_iter it; | |
1091 | struct task_struct *task; | |
1092 | ||
1093 | cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ | |
1094 | ||
1095 | guarantee_online_mems(cs, &newmems); | |
1096 | ||
1097 | /* | |
1098 | * The mpol_rebind_mm() call takes mmap_sem, which we couldn't | |
1099 | * take while holding tasklist_lock. Forks can happen - the | |
1100 | * mpol_dup() cpuset_being_rebound check will catch such forks, | |
1101 | * and rebind their vma mempolicies too. Because we still hold | |
1102 | * the global cpuset_mutex, we know that no other rebind effort | |
1103 | * will be contending for the global variable cpuset_being_rebound. | |
1104 | * It's ok if we rebind the same mm twice; mpol_rebind_mm() | |
1105 | * is idempotent. Also migrate pages in each mm to new nodes. | |
1106 | */ | |
1107 | css_task_iter_start(&cs->css, &it); | |
1108 | while ((task = css_task_iter_next(&it))) { | |
1109 | struct mm_struct *mm; | |
1110 | bool migrate; | |
1111 | ||
1112 | cpuset_change_task_nodemask(task, &newmems); | |
1113 | ||
1114 | mm = get_task_mm(task); | |
1115 | if (!mm) | |
1116 | continue; | |
1117 | ||
1118 | migrate = is_memory_migrate(cs); | |
1119 | ||
1120 | mpol_rebind_mm(mm, &cs->mems_allowed); | |
1121 | if (migrate) | |
1122 | cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems); | |
1123 | else | |
1124 | mmput(mm); | |
1125 | } | |
1126 | css_task_iter_end(&it); | |
1127 | ||
1128 | /* | |
1129 | * All the tasks' nodemasks have been updated, update | |
1130 | * cs->old_mems_allowed. | |
1131 | */ | |
1132 | cs->old_mems_allowed = newmems; | |
1133 | ||
1134 | /* We're done rebinding vmas to this cpuset's new mems_allowed. */ | |
1135 | cpuset_being_rebound = NULL; | |
1136 | } | |
1137 | ||
1138 | /* | |
1139 | * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree | |
1140 | * @cs: the cpuset to consider | |
1141 | * @new_mems: a temp variable for calculating new effective_mems | |
1142 | * | |
1143 | * When configured nodemask is changed, the effective nodemasks of this cpuset | |
1144 | * and all its descendants need to be updated. | |
1145 | * | |
1146 | * On legacy hiearchy, effective_mems will be the same with mems_allowed. | |
1147 | * | |
1148 | * Called with cpuset_mutex held | |
1149 | */ | |
1150 | static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) | |
1151 | { | |
1152 | struct cpuset *cp; | |
1153 | struct cgroup_subsys_state *pos_css; | |
1154 | ||
1155 | rcu_read_lock(); | |
1156 | cpuset_for_each_descendant_pre(cp, pos_css, cs) { | |
1157 | struct cpuset *parent = parent_cs(cp); | |
1158 | ||
1159 | nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems); | |
1160 | ||
1161 | /* | |
1162 | * If it becomes empty, inherit the effective mask of the | |
1163 | * parent, which is guaranteed to have some MEMs. | |
1164 | */ | |
1165 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
1166 | nodes_empty(*new_mems)) | |
1167 | *new_mems = parent->effective_mems; | |
1168 | ||
1169 | /* Skip the whole subtree if the nodemask remains the same. */ | |
1170 | if (nodes_equal(*new_mems, cp->effective_mems)) { | |
1171 | pos_css = css_rightmost_descendant(pos_css); | |
1172 | continue; | |
1173 | } | |
1174 | ||
1175 | if (!css_tryget_online(&cp->css)) | |
1176 | continue; | |
1177 | rcu_read_unlock(); | |
1178 | ||
1179 | spin_lock_irq(&callback_lock); | |
1180 | cp->effective_mems = *new_mems; | |
1181 | spin_unlock_irq(&callback_lock); | |
1182 | ||
1183 | WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
1184 | !nodes_equal(cp->mems_allowed, cp->effective_mems)); | |
1185 | ||
1186 | update_tasks_nodemask(cp); | |
1187 | ||
1188 | rcu_read_lock(); | |
1189 | css_put(&cp->css); | |
1190 | } | |
1191 | rcu_read_unlock(); | |
1192 | } | |
1193 | ||
1194 | /* | |
1195 | * Handle user request to change the 'mems' memory placement | |
1196 | * of a cpuset. Needs to validate the request, update the | |
1197 | * cpusets mems_allowed, and for each task in the cpuset, | |
1198 | * update mems_allowed and rebind task's mempolicy and any vma | |
1199 | * mempolicies and if the cpuset is marked 'memory_migrate', | |
1200 | * migrate the tasks pages to the new memory. | |
1201 | * | |
1202 | * Call with cpuset_mutex held. May take callback_lock during call. | |
1203 | * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, | |
1204 | * lock each such tasks mm->mmap_sem, scan its vma's and rebind | |
1205 | * their mempolicies to the cpusets new mems_allowed. | |
1206 | */ | |
1207 | static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, | |
1208 | const char *buf) | |
1209 | { | |
1210 | int retval; | |
1211 | ||
1212 | /* | |
1213 | * top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; | |
1214 | * it's read-only | |
1215 | */ | |
1216 | if (cs == &top_cpuset) { | |
1217 | retval = -EACCES; | |
1218 | goto done; | |
1219 | } | |
1220 | ||
1221 | /* | |
1222 | * An empty mems_allowed is ok iff there are no tasks in the cpuset. | |
1223 | * Since nodelist_parse() fails on an empty mask, we special case | |
1224 | * that parsing. The validate_change() call ensures that cpusets | |
1225 | * with tasks have memory. | |
1226 | */ | |
1227 | if (!*buf) { | |
1228 | nodes_clear(trialcs->mems_allowed); | |
1229 | } else { | |
1230 | retval = nodelist_parse(buf, trialcs->mems_allowed); | |
1231 | if (retval < 0) | |
1232 | goto done; | |
1233 | ||
1234 | if (!nodes_subset(trialcs->mems_allowed, | |
1235 | top_cpuset.mems_allowed)) { | |
1236 | retval = -EINVAL; | |
1237 | goto done; | |
1238 | } | |
1239 | } | |
1240 | ||
1241 | if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) { | |
1242 | retval = 0; /* Too easy - nothing to do */ | |
1243 | goto done; | |
1244 | } | |
1245 | retval = validate_change(cs, trialcs); | |
1246 | if (retval < 0) | |
1247 | goto done; | |
1248 | ||
1249 | spin_lock_irq(&callback_lock); | |
1250 | cs->mems_allowed = trialcs->mems_allowed; | |
1251 | spin_unlock_irq(&callback_lock); | |
1252 | ||
1253 | /* use trialcs->mems_allowed as a temp variable */ | |
1254 | update_nodemasks_hier(cs, &trialcs->mems_allowed); | |
1255 | done: | |
1256 | return retval; | |
1257 | } | |
1258 | ||
1259 | int current_cpuset_is_being_rebound(void) | |
1260 | { | |
1261 | int ret; | |
1262 | ||
1263 | rcu_read_lock(); | |
1264 | ret = task_cs(current) == cpuset_being_rebound; | |
1265 | rcu_read_unlock(); | |
1266 | ||
1267 | return ret; | |
1268 | } | |
1269 | ||
1270 | static int update_relax_domain_level(struct cpuset *cs, s64 val) | |
1271 | { | |
1272 | #ifdef CONFIG_SMP | |
1273 | if (val < -1 || val >= sched_domain_level_max) | |
1274 | return -EINVAL; | |
1275 | #endif | |
1276 | ||
1277 | if (val != cs->relax_domain_level) { | |
1278 | cs->relax_domain_level = val; | |
1279 | if (!cpumask_empty(cs->cpus_allowed) && | |
1280 | is_sched_load_balance(cs)) | |
1281 | rebuild_sched_domains_locked(); | |
1282 | } | |
1283 | ||
1284 | return 0; | |
1285 | } | |
1286 | ||
1287 | /** | |
1288 | * update_tasks_flags - update the spread flags of tasks in the cpuset. | |
1289 | * @cs: the cpuset in which each task's spread flags needs to be changed | |
1290 | * | |
1291 | * Iterate through each task of @cs updating its spread flags. As this | |
1292 | * function is called with cpuset_mutex held, cpuset membership stays | |
1293 | * stable. | |
1294 | */ | |
1295 | static void update_tasks_flags(struct cpuset *cs) | |
1296 | { | |
1297 | struct css_task_iter it; | |
1298 | struct task_struct *task; | |
1299 | ||
1300 | css_task_iter_start(&cs->css, &it); | |
1301 | while ((task = css_task_iter_next(&it))) | |
1302 | cpuset_update_task_spread_flag(cs, task); | |
1303 | css_task_iter_end(&it); | |
1304 | } | |
1305 | ||
1306 | /* | |
1307 | * update_flag - read a 0 or a 1 in a file and update associated flag | |
1308 | * bit: the bit to update (see cpuset_flagbits_t) | |
1309 | * cs: the cpuset to update | |
1310 | * turning_on: whether the flag is being set or cleared | |
1311 | * | |
1312 | * Call with cpuset_mutex held. | |
1313 | */ | |
1314 | ||
1315 | static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, | |
1316 | int turning_on) | |
1317 | { | |
1318 | struct cpuset *trialcs; | |
1319 | int balance_flag_changed; | |
1320 | int spread_flag_changed; | |
1321 | int err; | |
1322 | ||
1323 | trialcs = alloc_trial_cpuset(cs); | |
1324 | if (!trialcs) | |
1325 | return -ENOMEM; | |
1326 | ||
1327 | if (turning_on) | |
1328 | set_bit(bit, &trialcs->flags); | |
1329 | else | |
1330 | clear_bit(bit, &trialcs->flags); | |
1331 | ||
1332 | err = validate_change(cs, trialcs); | |
1333 | if (err < 0) | |
1334 | goto out; | |
1335 | ||
1336 | balance_flag_changed = (is_sched_load_balance(cs) != | |
1337 | is_sched_load_balance(trialcs)); | |
1338 | ||
1339 | spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) | |
1340 | || (is_spread_page(cs) != is_spread_page(trialcs))); | |
1341 | ||
1342 | spin_lock_irq(&callback_lock); | |
1343 | cs->flags = trialcs->flags; | |
1344 | spin_unlock_irq(&callback_lock); | |
1345 | ||
1346 | if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) | |
1347 | rebuild_sched_domains_locked(); | |
1348 | ||
1349 | if (spread_flag_changed) | |
1350 | update_tasks_flags(cs); | |
1351 | out: | |
1352 | free_trial_cpuset(trialcs); | |
1353 | return err; | |
1354 | } | |
1355 | ||
1356 | /* | |
1357 | * Frequency meter - How fast is some event occurring? | |
1358 | * | |
1359 | * These routines manage a digitally filtered, constant time based, | |
1360 | * event frequency meter. There are four routines: | |
1361 | * fmeter_init() - initialize a frequency meter. | |
1362 | * fmeter_markevent() - called each time the event happens. | |
1363 | * fmeter_getrate() - returns the recent rate of such events. | |
1364 | * fmeter_update() - internal routine used to update fmeter. | |
1365 | * | |
1366 | * A common data structure is passed to each of these routines, | |
1367 | * which is used to keep track of the state required to manage the | |
1368 | * frequency meter and its digital filter. | |
1369 | * | |
1370 | * The filter works on the number of events marked per unit time. | |
1371 | * The filter is single-pole low-pass recursive (IIR). The time unit | |
1372 | * is 1 second. Arithmetic is done using 32-bit integers scaled to | |
1373 | * simulate 3 decimal digits of precision (multiplied by 1000). | |
1374 | * | |
1375 | * With an FM_COEF of 933, and a time base of 1 second, the filter | |
1376 | * has a half-life of 10 seconds, meaning that if the events quit | |
1377 | * happening, then the rate returned from the fmeter_getrate() | |
1378 | * will be cut in half each 10 seconds, until it converges to zero. | |
1379 | * | |
1380 | * It is not worth doing a real infinitely recursive filter. If more | |
1381 | * than FM_MAXTICKS ticks have elapsed since the last filter event, | |
1382 | * just compute FM_MAXTICKS ticks worth, by which point the level | |
1383 | * will be stable. | |
1384 | * | |
1385 | * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid | |
1386 | * arithmetic overflow in the fmeter_update() routine. | |
1387 | * | |
1388 | * Given the simple 32 bit integer arithmetic used, this meter works | |
1389 | * best for reporting rates between one per millisecond (msec) and | |
1390 | * one per 32 (approx) seconds. At constant rates faster than one | |
1391 | * per msec it maxes out at values just under 1,000,000. At constant | |
1392 | * rates between one per msec, and one per second it will stabilize | |
1393 | * to a value N*1000, where N is the rate of events per second. | |
1394 | * At constant rates between one per second and one per 32 seconds, | |
1395 | * it will be choppy, moving up on the seconds that have an event, | |
1396 | * and then decaying until the next event. At rates slower than | |
1397 | * about one in 32 seconds, it decays all the way back to zero between | |
1398 | * each event. | |
1399 | */ | |
1400 | ||
1401 | #define FM_COEF 933 /* coefficient for half-life of 10 secs */ | |
1402 | #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */ | |
1403 | #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ | |
1404 | #define FM_SCALE 1000 /* faux fixed point scale */ | |
1405 | ||
1406 | /* Initialize a frequency meter */ | |
1407 | static void fmeter_init(struct fmeter *fmp) | |
1408 | { | |
1409 | fmp->cnt = 0; | |
1410 | fmp->val = 0; | |
1411 | fmp->time = 0; | |
1412 | spin_lock_init(&fmp->lock); | |
1413 | } | |
1414 | ||
1415 | /* Internal meter update - process cnt events and update value */ | |
1416 | static void fmeter_update(struct fmeter *fmp) | |
1417 | { | |
1418 | time64_t now; | |
1419 | u32 ticks; | |
1420 | ||
1421 | now = ktime_get_seconds(); | |
1422 | ticks = now - fmp->time; | |
1423 | ||
1424 | if (ticks == 0) | |
1425 | return; | |
1426 | ||
1427 | ticks = min(FM_MAXTICKS, ticks); | |
1428 | while (ticks-- > 0) | |
1429 | fmp->val = (FM_COEF * fmp->val) / FM_SCALE; | |
1430 | fmp->time = now; | |
1431 | ||
1432 | fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; | |
1433 | fmp->cnt = 0; | |
1434 | } | |
1435 | ||
1436 | /* Process any previous ticks, then bump cnt by one (times scale). */ | |
1437 | static void fmeter_markevent(struct fmeter *fmp) | |
1438 | { | |
1439 | spin_lock(&fmp->lock); | |
1440 | fmeter_update(fmp); | |
1441 | fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); | |
1442 | spin_unlock(&fmp->lock); | |
1443 | } | |
1444 | ||
1445 | /* Process any previous ticks, then return current value. */ | |
1446 | static int fmeter_getrate(struct fmeter *fmp) | |
1447 | { | |
1448 | int val; | |
1449 | ||
1450 | spin_lock(&fmp->lock); | |
1451 | fmeter_update(fmp); | |
1452 | val = fmp->val; | |
1453 | spin_unlock(&fmp->lock); | |
1454 | return val; | |
1455 | } | |
1456 | ||
1457 | static struct cpuset *cpuset_attach_old_cs; | |
1458 | ||
1459 | /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */ | |
1460 | static int cpuset_can_attach(struct cgroup_taskset *tset) | |
1461 | { | |
1462 | struct cgroup_subsys_state *css; | |
1463 | struct cpuset *cs; | |
1464 | struct task_struct *task; | |
1465 | int ret; | |
1466 | ||
1467 | /* used later by cpuset_attach() */ | |
1468 | cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css)); | |
1469 | cs = css_cs(css); | |
1470 | ||
1471 | mutex_lock(&cpuset_mutex); | |
1472 | ||
1473 | /* allow moving tasks into an empty cpuset if on default hierarchy */ | |
1474 | ret = -ENOSPC; | |
1475 | if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && | |
1476 | (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) | |
1477 | goto out_unlock; | |
1478 | ||
1479 | cgroup_taskset_for_each(task, css, tset) { | |
1480 | ret = task_can_attach(task, cs->cpus_allowed); | |
1481 | if (ret) | |
1482 | goto out_unlock; | |
1483 | ret = security_task_setscheduler(task); | |
1484 | if (ret) | |
1485 | goto out_unlock; | |
1486 | } | |
1487 | ||
1488 | /* | |
1489 | * Mark attach is in progress. This makes validate_change() fail | |
1490 | * changes which zero cpus/mems_allowed. | |
1491 | */ | |
1492 | cs->attach_in_progress++; | |
1493 | ret = 0; | |
1494 | out_unlock: | |
1495 | mutex_unlock(&cpuset_mutex); | |
1496 | return ret; | |
1497 | } | |
1498 | ||
1499 | static void cpuset_cancel_attach(struct cgroup_taskset *tset) | |
1500 | { | |
1501 | struct cgroup_subsys_state *css; | |
1502 | struct cpuset *cs; | |
1503 | ||
1504 | cgroup_taskset_first(tset, &css); | |
1505 | cs = css_cs(css); | |
1506 | ||
1507 | mutex_lock(&cpuset_mutex); | |
1508 | css_cs(css)->attach_in_progress--; | |
1509 | mutex_unlock(&cpuset_mutex); | |
1510 | } | |
1511 | ||
1512 | /* | |
1513 | * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach() | |
1514 | * but we can't allocate it dynamically there. Define it global and | |
1515 | * allocate from cpuset_init(). | |
1516 | */ | |
1517 | static cpumask_var_t cpus_attach; | |
1518 | ||
1519 | static void cpuset_attach(struct cgroup_taskset *tset) | |
1520 | { | |
1521 | /* static buf protected by cpuset_mutex */ | |
1522 | static nodemask_t cpuset_attach_nodemask_to; | |
1523 | struct task_struct *task; | |
1524 | struct task_struct *leader; | |
1525 | struct cgroup_subsys_state *css; | |
1526 | struct cpuset *cs; | |
1527 | struct cpuset *oldcs = cpuset_attach_old_cs; | |
1528 | ||
1529 | cgroup_taskset_first(tset, &css); | |
1530 | cs = css_cs(css); | |
1531 | ||
1532 | mutex_lock(&cpuset_mutex); | |
1533 | ||
1534 | /* prepare for attach */ | |
1535 | if (cs == &top_cpuset) | |
1536 | cpumask_copy(cpus_attach, cpu_possible_mask); | |
1537 | else | |
1538 | guarantee_online_cpus(cs, cpus_attach); | |
1539 | ||
1540 | guarantee_online_mems(cs, &cpuset_attach_nodemask_to); | |
1541 | ||
1542 | cgroup_taskset_for_each(task, css, tset) { | |
1543 | /* | |
1544 | * can_attach beforehand should guarantee that this doesn't | |
1545 | * fail. TODO: have a better way to handle failure here | |
1546 | */ | |
1547 | WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); | |
1548 | ||
1549 | cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); | |
1550 | cpuset_update_task_spread_flag(cs, task); | |
1551 | } | |
1552 | ||
1553 | /* | |
1554 | * Change mm for all threadgroup leaders. This is expensive and may | |
1555 | * sleep and should be moved outside migration path proper. | |
1556 | */ | |
1557 | cpuset_attach_nodemask_to = cs->effective_mems; | |
1558 | cgroup_taskset_for_each_leader(leader, css, tset) { | |
1559 | struct mm_struct *mm = get_task_mm(leader); | |
1560 | ||
1561 | if (mm) { | |
1562 | mpol_rebind_mm(mm, &cpuset_attach_nodemask_to); | |
1563 | ||
1564 | /* | |
1565 | * old_mems_allowed is the same with mems_allowed | |
1566 | * here, except if this task is being moved | |
1567 | * automatically due to hotplug. In that case | |
1568 | * @mems_allowed has been updated and is empty, so | |
1569 | * @old_mems_allowed is the right nodesets that we | |
1570 | * migrate mm from. | |
1571 | */ | |
1572 | if (is_memory_migrate(cs)) | |
1573 | cpuset_migrate_mm(mm, &oldcs->old_mems_allowed, | |
1574 | &cpuset_attach_nodemask_to); | |
1575 | else | |
1576 | mmput(mm); | |
1577 | } | |
1578 | } | |
1579 | ||
1580 | cs->old_mems_allowed = cpuset_attach_nodemask_to; | |
1581 | ||
1582 | cs->attach_in_progress--; | |
1583 | if (!cs->attach_in_progress) | |
1584 | wake_up(&cpuset_attach_wq); | |
1585 | ||
1586 | mutex_unlock(&cpuset_mutex); | |
1587 | } | |
1588 | ||
1589 | /* The various types of files and directories in a cpuset file system */ | |
1590 | ||
1591 | typedef enum { | |
1592 | FILE_MEMORY_MIGRATE, | |
1593 | FILE_CPULIST, | |
1594 | FILE_MEMLIST, | |
1595 | FILE_EFFECTIVE_CPULIST, | |
1596 | FILE_EFFECTIVE_MEMLIST, | |
1597 | FILE_CPU_EXCLUSIVE, | |
1598 | FILE_MEM_EXCLUSIVE, | |
1599 | FILE_MEM_HARDWALL, | |
1600 | FILE_SCHED_LOAD_BALANCE, | |
1601 | FILE_SCHED_RELAX_DOMAIN_LEVEL, | |
1602 | FILE_MEMORY_PRESSURE_ENABLED, | |
1603 | FILE_MEMORY_PRESSURE, | |
1604 | FILE_SPREAD_PAGE, | |
1605 | FILE_SPREAD_SLAB, | |
1606 | } cpuset_filetype_t; | |
1607 | ||
1608 | static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, | |
1609 | u64 val) | |
1610 | { | |
1611 | struct cpuset *cs = css_cs(css); | |
1612 | cpuset_filetype_t type = cft->private; | |
1613 | int retval = 0; | |
1614 | ||
1615 | mutex_lock(&cpuset_mutex); | |
1616 | if (!is_cpuset_online(cs)) { | |
1617 | retval = -ENODEV; | |
1618 | goto out_unlock; | |
1619 | } | |
1620 | ||
1621 | switch (type) { | |
1622 | case FILE_CPU_EXCLUSIVE: | |
1623 | retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); | |
1624 | break; | |
1625 | case FILE_MEM_EXCLUSIVE: | |
1626 | retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); | |
1627 | break; | |
1628 | case FILE_MEM_HARDWALL: | |
1629 | retval = update_flag(CS_MEM_HARDWALL, cs, val); | |
1630 | break; | |
1631 | case FILE_SCHED_LOAD_BALANCE: | |
1632 | retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); | |
1633 | break; | |
1634 | case FILE_MEMORY_MIGRATE: | |
1635 | retval = update_flag(CS_MEMORY_MIGRATE, cs, val); | |
1636 | break; | |
1637 | case FILE_MEMORY_PRESSURE_ENABLED: | |
1638 | cpuset_memory_pressure_enabled = !!val; | |
1639 | break; | |
1640 | case FILE_SPREAD_PAGE: | |
1641 | retval = update_flag(CS_SPREAD_PAGE, cs, val); | |
1642 | break; | |
1643 | case FILE_SPREAD_SLAB: | |
1644 | retval = update_flag(CS_SPREAD_SLAB, cs, val); | |
1645 | break; | |
1646 | default: | |
1647 | retval = -EINVAL; | |
1648 | break; | |
1649 | } | |
1650 | out_unlock: | |
1651 | mutex_unlock(&cpuset_mutex); | |
1652 | return retval; | |
1653 | } | |
1654 | ||
1655 | static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, | |
1656 | s64 val) | |
1657 | { | |
1658 | struct cpuset *cs = css_cs(css); | |
1659 | cpuset_filetype_t type = cft->private; | |
1660 | int retval = -ENODEV; | |
1661 | ||
1662 | mutex_lock(&cpuset_mutex); | |
1663 | if (!is_cpuset_online(cs)) | |
1664 | goto out_unlock; | |
1665 | ||
1666 | switch (type) { | |
1667 | case FILE_SCHED_RELAX_DOMAIN_LEVEL: | |
1668 | retval = update_relax_domain_level(cs, val); | |
1669 | break; | |
1670 | default: | |
1671 | retval = -EINVAL; | |
1672 | break; | |
1673 | } | |
1674 | out_unlock: | |
1675 | mutex_unlock(&cpuset_mutex); | |
1676 | return retval; | |
1677 | } | |
1678 | ||
1679 | /* | |
1680 | * Common handling for a write to a "cpus" or "mems" file. | |
1681 | */ | |
1682 | static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, | |
1683 | char *buf, size_t nbytes, loff_t off) | |
1684 | { | |
1685 | struct cpuset *cs = css_cs(of_css(of)); | |
1686 | struct cpuset *trialcs; | |
1687 | int retval = -ENODEV; | |
1688 | ||
1689 | buf = strstrip(buf); | |
1690 | ||
1691 | /* | |
1692 | * CPU or memory hotunplug may leave @cs w/o any execution | |
1693 | * resources, in which case the hotplug code asynchronously updates | |
1694 | * configuration and transfers all tasks to the nearest ancestor | |
1695 | * which can execute. | |
1696 | * | |
1697 | * As writes to "cpus" or "mems" may restore @cs's execution | |
1698 | * resources, wait for the previously scheduled operations before | |
1699 | * proceeding, so that we don't end up keep removing tasks added | |
1700 | * after execution capability is restored. | |
1701 | * | |
1702 | * cpuset_hotplug_work calls back into cgroup core via | |
1703 | * cgroup_transfer_tasks() and waiting for it from a cgroupfs | |
1704 | * operation like this one can lead to a deadlock through kernfs | |
1705 | * active_ref protection. Let's break the protection. Losing the | |
1706 | * protection is okay as we check whether @cs is online after | |
1707 | * grabbing cpuset_mutex anyway. This only happens on the legacy | |
1708 | * hierarchies. | |
1709 | */ | |
1710 | css_get(&cs->css); | |
1711 | kernfs_break_active_protection(of->kn); | |
1712 | flush_work(&cpuset_hotplug_work); | |
1713 | ||
1714 | mutex_lock(&cpuset_mutex); | |
1715 | if (!is_cpuset_online(cs)) | |
1716 | goto out_unlock; | |
1717 | ||
1718 | trialcs = alloc_trial_cpuset(cs); | |
1719 | if (!trialcs) { | |
1720 | retval = -ENOMEM; | |
1721 | goto out_unlock; | |
1722 | } | |
1723 | ||
1724 | switch (of_cft(of)->private) { | |
1725 | case FILE_CPULIST: | |
1726 | retval = update_cpumask(cs, trialcs, buf); | |
1727 | break; | |
1728 | case FILE_MEMLIST: | |
1729 | retval = update_nodemask(cs, trialcs, buf); | |
1730 | break; | |
1731 | default: | |
1732 | retval = -EINVAL; | |
1733 | break; | |
1734 | } | |
1735 | ||
1736 | free_trial_cpuset(trialcs); | |
1737 | out_unlock: | |
1738 | mutex_unlock(&cpuset_mutex); | |
1739 | kernfs_unbreak_active_protection(of->kn); | |
1740 | css_put(&cs->css); | |
1741 | flush_workqueue(cpuset_migrate_mm_wq); | |
1742 | return retval ?: nbytes; | |
1743 | } | |
1744 | ||
1745 | /* | |
1746 | * These ascii lists should be read in a single call, by using a user | |
1747 | * buffer large enough to hold the entire map. If read in smaller | |
1748 | * chunks, there is no guarantee of atomicity. Since the display format | |
1749 | * used, list of ranges of sequential numbers, is variable length, | |
1750 | * and since these maps can change value dynamically, one could read | |
1751 | * gibberish by doing partial reads while a list was changing. | |
1752 | */ | |
1753 | static int cpuset_common_seq_show(struct seq_file *sf, void *v) | |
1754 | { | |
1755 | struct cpuset *cs = css_cs(seq_css(sf)); | |
1756 | cpuset_filetype_t type = seq_cft(sf)->private; | |
1757 | int ret = 0; | |
1758 | ||
1759 | spin_lock_irq(&callback_lock); | |
1760 | ||
1761 | switch (type) { | |
1762 | case FILE_CPULIST: | |
1763 | seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed)); | |
1764 | break; | |
1765 | case FILE_MEMLIST: | |
1766 | seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed)); | |
1767 | break; | |
1768 | case FILE_EFFECTIVE_CPULIST: | |
1769 | seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus)); | |
1770 | break; | |
1771 | case FILE_EFFECTIVE_MEMLIST: | |
1772 | seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems)); | |
1773 | break; | |
1774 | default: | |
1775 | ret = -EINVAL; | |
1776 | } | |
1777 | ||
1778 | spin_unlock_irq(&callback_lock); | |
1779 | return ret; | |
1780 | } | |
1781 | ||
1782 | static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) | |
1783 | { | |
1784 | struct cpuset *cs = css_cs(css); | |
1785 | cpuset_filetype_t type = cft->private; | |
1786 | switch (type) { | |
1787 | case FILE_CPU_EXCLUSIVE: | |
1788 | return is_cpu_exclusive(cs); | |
1789 | case FILE_MEM_EXCLUSIVE: | |
1790 | return is_mem_exclusive(cs); | |
1791 | case FILE_MEM_HARDWALL: | |
1792 | return is_mem_hardwall(cs); | |
1793 | case FILE_SCHED_LOAD_BALANCE: | |
1794 | return is_sched_load_balance(cs); | |
1795 | case FILE_MEMORY_MIGRATE: | |
1796 | return is_memory_migrate(cs); | |
1797 | case FILE_MEMORY_PRESSURE_ENABLED: | |
1798 | return cpuset_memory_pressure_enabled; | |
1799 | case FILE_MEMORY_PRESSURE: | |
1800 | return fmeter_getrate(&cs->fmeter); | |
1801 | case FILE_SPREAD_PAGE: | |
1802 | return is_spread_page(cs); | |
1803 | case FILE_SPREAD_SLAB: | |
1804 | return is_spread_slab(cs); | |
1805 | default: | |
1806 | BUG(); | |
1807 | } | |
1808 | ||
1809 | /* Unreachable but makes gcc happy */ | |
1810 | return 0; | |
1811 | } | |
1812 | ||
1813 | static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) | |
1814 | { | |
1815 | struct cpuset *cs = css_cs(css); | |
1816 | cpuset_filetype_t type = cft->private; | |
1817 | switch (type) { | |
1818 | case FILE_SCHED_RELAX_DOMAIN_LEVEL: | |
1819 | return cs->relax_domain_level; | |
1820 | default: | |
1821 | BUG(); | |
1822 | } | |
1823 | ||
1824 | /* Unrechable but makes gcc happy */ | |
1825 | return 0; | |
1826 | } | |
1827 | ||
1828 | ||
1829 | /* | |
1830 | * for the common functions, 'private' gives the type of file | |
1831 | */ | |
1832 | ||
1833 | static struct cftype files[] = { | |
1834 | { | |
1835 | .name = "cpus", | |
1836 | .seq_show = cpuset_common_seq_show, | |
1837 | .write = cpuset_write_resmask, | |
1838 | .max_write_len = (100U + 6 * NR_CPUS), | |
1839 | .private = FILE_CPULIST, | |
1840 | }, | |
1841 | ||
1842 | { | |
1843 | .name = "mems", | |
1844 | .seq_show = cpuset_common_seq_show, | |
1845 | .write = cpuset_write_resmask, | |
1846 | .max_write_len = (100U + 6 * MAX_NUMNODES), | |
1847 | .private = FILE_MEMLIST, | |
1848 | }, | |
1849 | ||
1850 | { | |
1851 | .name = "effective_cpus", | |
1852 | .seq_show = cpuset_common_seq_show, | |
1853 | .private = FILE_EFFECTIVE_CPULIST, | |
1854 | }, | |
1855 | ||
1856 | { | |
1857 | .name = "effective_mems", | |
1858 | .seq_show = cpuset_common_seq_show, | |
1859 | .private = FILE_EFFECTIVE_MEMLIST, | |
1860 | }, | |
1861 | ||
1862 | { | |
1863 | .name = "cpu_exclusive", | |
1864 | .read_u64 = cpuset_read_u64, | |
1865 | .write_u64 = cpuset_write_u64, | |
1866 | .private = FILE_CPU_EXCLUSIVE, | |
1867 | }, | |
1868 | ||
1869 | { | |
1870 | .name = "mem_exclusive", | |
1871 | .read_u64 = cpuset_read_u64, | |
1872 | .write_u64 = cpuset_write_u64, | |
1873 | .private = FILE_MEM_EXCLUSIVE, | |
1874 | }, | |
1875 | ||
1876 | { | |
1877 | .name = "mem_hardwall", | |
1878 | .read_u64 = cpuset_read_u64, | |
1879 | .write_u64 = cpuset_write_u64, | |
1880 | .private = FILE_MEM_HARDWALL, | |
1881 | }, | |
1882 | ||
1883 | { | |
1884 | .name = "sched_load_balance", | |
1885 | .read_u64 = cpuset_read_u64, | |
1886 | .write_u64 = cpuset_write_u64, | |
1887 | .private = FILE_SCHED_LOAD_BALANCE, | |
1888 | }, | |
1889 | ||
1890 | { | |
1891 | .name = "sched_relax_domain_level", | |
1892 | .read_s64 = cpuset_read_s64, | |
1893 | .write_s64 = cpuset_write_s64, | |
1894 | .private = FILE_SCHED_RELAX_DOMAIN_LEVEL, | |
1895 | }, | |
1896 | ||
1897 | { | |
1898 | .name = "memory_migrate", | |
1899 | .read_u64 = cpuset_read_u64, | |
1900 | .write_u64 = cpuset_write_u64, | |
1901 | .private = FILE_MEMORY_MIGRATE, | |
1902 | }, | |
1903 | ||
1904 | { | |
1905 | .name = "memory_pressure", | |
1906 | .read_u64 = cpuset_read_u64, | |
1907 | }, | |
1908 | ||
1909 | { | |
1910 | .name = "memory_spread_page", | |
1911 | .read_u64 = cpuset_read_u64, | |
1912 | .write_u64 = cpuset_write_u64, | |
1913 | .private = FILE_SPREAD_PAGE, | |
1914 | }, | |
1915 | ||
1916 | { | |
1917 | .name = "memory_spread_slab", | |
1918 | .read_u64 = cpuset_read_u64, | |
1919 | .write_u64 = cpuset_write_u64, | |
1920 | .private = FILE_SPREAD_SLAB, | |
1921 | }, | |
1922 | ||
1923 | { | |
1924 | .name = "memory_pressure_enabled", | |
1925 | .flags = CFTYPE_ONLY_ON_ROOT, | |
1926 | .read_u64 = cpuset_read_u64, | |
1927 | .write_u64 = cpuset_write_u64, | |
1928 | .private = FILE_MEMORY_PRESSURE_ENABLED, | |
1929 | }, | |
1930 | ||
1931 | { } /* terminate */ | |
1932 | }; | |
1933 | ||
1934 | /* | |
1935 | * cpuset_css_alloc - allocate a cpuset css | |
1936 | * cgrp: control group that the new cpuset will be part of | |
1937 | */ | |
1938 | ||
1939 | static struct cgroup_subsys_state * | |
1940 | cpuset_css_alloc(struct cgroup_subsys_state *parent_css) | |
1941 | { | |
1942 | struct cpuset *cs; | |
1943 | ||
1944 | if (!parent_css) | |
1945 | return &top_cpuset.css; | |
1946 | ||
1947 | cs = kzalloc(sizeof(*cs), GFP_KERNEL); | |
1948 | if (!cs) | |
1949 | return ERR_PTR(-ENOMEM); | |
1950 | if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) | |
1951 | goto free_cs; | |
1952 | if (!alloc_cpumask_var(&cs->effective_cpus, GFP_KERNEL)) | |
1953 | goto free_cpus; | |
1954 | ||
1955 | set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); | |
1956 | cpumask_clear(cs->cpus_allowed); | |
1957 | nodes_clear(cs->mems_allowed); | |
1958 | cpumask_clear(cs->effective_cpus); | |
1959 | nodes_clear(cs->effective_mems); | |
1960 | fmeter_init(&cs->fmeter); | |
1961 | cs->relax_domain_level = -1; | |
1962 | ||
1963 | return &cs->css; | |
1964 | ||
1965 | free_cpus: | |
1966 | free_cpumask_var(cs->cpus_allowed); | |
1967 | free_cs: | |
1968 | kfree(cs); | |
1969 | return ERR_PTR(-ENOMEM); | |
1970 | } | |
1971 | ||
1972 | static int cpuset_css_online(struct cgroup_subsys_state *css) | |
1973 | { | |
1974 | struct cpuset *cs = css_cs(css); | |
1975 | struct cpuset *parent = parent_cs(cs); | |
1976 | struct cpuset *tmp_cs; | |
1977 | struct cgroup_subsys_state *pos_css; | |
1978 | ||
1979 | if (!parent) | |
1980 | return 0; | |
1981 | ||
1982 | mutex_lock(&cpuset_mutex); | |
1983 | ||
1984 | set_bit(CS_ONLINE, &cs->flags); | |
1985 | if (is_spread_page(parent)) | |
1986 | set_bit(CS_SPREAD_PAGE, &cs->flags); | |
1987 | if (is_spread_slab(parent)) | |
1988 | set_bit(CS_SPREAD_SLAB, &cs->flags); | |
1989 | ||
1990 | cpuset_inc(); | |
1991 | ||
1992 | spin_lock_irq(&callback_lock); | |
1993 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { | |
1994 | cpumask_copy(cs->effective_cpus, parent->effective_cpus); | |
1995 | cs->effective_mems = parent->effective_mems; | |
1996 | } | |
1997 | spin_unlock_irq(&callback_lock); | |
1998 | ||
1999 | if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) | |
2000 | goto out_unlock; | |
2001 | ||
2002 | /* | |
2003 | * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is | |
2004 | * set. This flag handling is implemented in cgroup core for | |
2005 | * histrical reasons - the flag may be specified during mount. | |
2006 | * | |
2007 | * Currently, if any sibling cpusets have exclusive cpus or mem, we | |
2008 | * refuse to clone the configuration - thereby refusing the task to | |
2009 | * be entered, and as a result refusing the sys_unshare() or | |
2010 | * clone() which initiated it. If this becomes a problem for some | |
2011 | * users who wish to allow that scenario, then this could be | |
2012 | * changed to grant parent->cpus_allowed-sibling_cpus_exclusive | |
2013 | * (and likewise for mems) to the new cgroup. | |
2014 | */ | |
2015 | rcu_read_lock(); | |
2016 | cpuset_for_each_child(tmp_cs, pos_css, parent) { | |
2017 | if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) { | |
2018 | rcu_read_unlock(); | |
2019 | goto out_unlock; | |
2020 | } | |
2021 | } | |
2022 | rcu_read_unlock(); | |
2023 | ||
2024 | spin_lock_irq(&callback_lock); | |
2025 | cs->mems_allowed = parent->mems_allowed; | |
2026 | cs->effective_mems = parent->mems_allowed; | |
2027 | cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); | |
2028 | cpumask_copy(cs->effective_cpus, parent->cpus_allowed); | |
2029 | spin_unlock_irq(&callback_lock); | |
2030 | out_unlock: | |
2031 | mutex_unlock(&cpuset_mutex); | |
2032 | return 0; | |
2033 | } | |
2034 | ||
2035 | /* | |
2036 | * If the cpuset being removed has its flag 'sched_load_balance' | |
2037 | * enabled, then simulate turning sched_load_balance off, which | |
2038 | * will call rebuild_sched_domains_locked(). | |
2039 | */ | |
2040 | ||
2041 | static void cpuset_css_offline(struct cgroup_subsys_state *css) | |
2042 | { | |
2043 | struct cpuset *cs = css_cs(css); | |
2044 | ||
2045 | mutex_lock(&cpuset_mutex); | |
2046 | ||
2047 | if (is_sched_load_balance(cs)) | |
2048 | update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); | |
2049 | ||
2050 | cpuset_dec(); | |
2051 | clear_bit(CS_ONLINE, &cs->flags); | |
2052 | ||
2053 | mutex_unlock(&cpuset_mutex); | |
2054 | } | |
2055 | ||
2056 | static void cpuset_css_free(struct cgroup_subsys_state *css) | |
2057 | { | |
2058 | struct cpuset *cs = css_cs(css); | |
2059 | ||
2060 | free_cpumask_var(cs->effective_cpus); | |
2061 | free_cpumask_var(cs->cpus_allowed); | |
2062 | kfree(cs); | |
2063 | } | |
2064 | ||
2065 | static void cpuset_bind(struct cgroup_subsys_state *root_css) | |
2066 | { | |
2067 | mutex_lock(&cpuset_mutex); | |
2068 | spin_lock_irq(&callback_lock); | |
2069 | ||
2070 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { | |
2071 | cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); | |
2072 | top_cpuset.mems_allowed = node_possible_map; | |
2073 | } else { | |
2074 | cpumask_copy(top_cpuset.cpus_allowed, | |
2075 | top_cpuset.effective_cpus); | |
2076 | top_cpuset.mems_allowed = top_cpuset.effective_mems; | |
2077 | } | |
2078 | ||
2079 | spin_unlock_irq(&callback_lock); | |
2080 | mutex_unlock(&cpuset_mutex); | |
2081 | } | |
2082 | ||
2083 | /* | |
2084 | * Make sure the new task conform to the current state of its parent, | |
2085 | * which could have been changed by cpuset just after it inherits the | |
2086 | * state from the parent and before it sits on the cgroup's task list. | |
2087 | */ | |
2088 | static void cpuset_fork(struct task_struct *task) | |
2089 | { | |
2090 | if (task_css_is_root(task, cpuset_cgrp_id)) | |
2091 | return; | |
2092 | ||
2093 | set_cpus_allowed_ptr(task, ¤t->cpus_allowed); | |
2094 | task->mems_allowed = current->mems_allowed; | |
2095 | } | |
2096 | ||
2097 | struct cgroup_subsys cpuset_cgrp_subsys = { | |
2098 | .css_alloc = cpuset_css_alloc, | |
2099 | .css_online = cpuset_css_online, | |
2100 | .css_offline = cpuset_css_offline, | |
2101 | .css_free = cpuset_css_free, | |
2102 | .can_attach = cpuset_can_attach, | |
2103 | .cancel_attach = cpuset_cancel_attach, | |
2104 | .attach = cpuset_attach, | |
2105 | .post_attach = cpuset_post_attach, | |
2106 | .bind = cpuset_bind, | |
2107 | .fork = cpuset_fork, | |
2108 | .legacy_cftypes = files, | |
2109 | .early_init = true, | |
2110 | }; | |
2111 | ||
2112 | /** | |
2113 | * cpuset_init - initialize cpusets at system boot | |
2114 | * | |
2115 | * Description: Initialize top_cpuset and the cpuset internal file system, | |
2116 | **/ | |
2117 | ||
2118 | int __init cpuset_init(void) | |
2119 | { | |
2120 | int err = 0; | |
2121 | ||
2122 | if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)) | |
2123 | BUG(); | |
2124 | if (!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL)) | |
2125 | BUG(); | |
2126 | ||
2127 | cpumask_setall(top_cpuset.cpus_allowed); | |
2128 | nodes_setall(top_cpuset.mems_allowed); | |
2129 | cpumask_setall(top_cpuset.effective_cpus); | |
2130 | nodes_setall(top_cpuset.effective_mems); | |
2131 | ||
2132 | fmeter_init(&top_cpuset.fmeter); | |
2133 | set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); | |
2134 | top_cpuset.relax_domain_level = -1; | |
2135 | ||
2136 | err = register_filesystem(&cpuset_fs_type); | |
2137 | if (err < 0) | |
2138 | return err; | |
2139 | ||
2140 | if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) | |
2141 | BUG(); | |
2142 | ||
2143 | return 0; | |
2144 | } | |
2145 | ||
2146 | /* | |
2147 | * If CPU and/or memory hotplug handlers, below, unplug any CPUs | |
2148 | * or memory nodes, we need to walk over the cpuset hierarchy, | |
2149 | * removing that CPU or node from all cpusets. If this removes the | |
2150 | * last CPU or node from a cpuset, then move the tasks in the empty | |
2151 | * cpuset to its next-highest non-empty parent. | |
2152 | */ | |
2153 | static void remove_tasks_in_empty_cpuset(struct cpuset *cs) | |
2154 | { | |
2155 | struct cpuset *parent; | |
2156 | ||
2157 | /* | |
2158 | * Find its next-highest non-empty parent, (top cpuset | |
2159 | * has online cpus, so can't be empty). | |
2160 | */ | |
2161 | parent = parent_cs(cs); | |
2162 | while (cpumask_empty(parent->cpus_allowed) || | |
2163 | nodes_empty(parent->mems_allowed)) | |
2164 | parent = parent_cs(parent); | |
2165 | ||
2166 | if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) { | |
2167 | pr_err("cpuset: failed to transfer tasks out of empty cpuset "); | |
2168 | pr_cont_cgroup_name(cs->css.cgroup); | |
2169 | pr_cont("\n"); | |
2170 | } | |
2171 | } | |
2172 | ||
2173 | static void | |
2174 | hotplug_update_tasks_legacy(struct cpuset *cs, | |
2175 | struct cpumask *new_cpus, nodemask_t *new_mems, | |
2176 | bool cpus_updated, bool mems_updated) | |
2177 | { | |
2178 | bool is_empty; | |
2179 | ||
2180 | spin_lock_irq(&callback_lock); | |
2181 | cpumask_copy(cs->cpus_allowed, new_cpus); | |
2182 | cpumask_copy(cs->effective_cpus, new_cpus); | |
2183 | cs->mems_allowed = *new_mems; | |
2184 | cs->effective_mems = *new_mems; | |
2185 | spin_unlock_irq(&callback_lock); | |
2186 | ||
2187 | /* | |
2188 | * Don't call update_tasks_cpumask() if the cpuset becomes empty, | |
2189 | * as the tasks will be migratecd to an ancestor. | |
2190 | */ | |
2191 | if (cpus_updated && !cpumask_empty(cs->cpus_allowed)) | |
2192 | update_tasks_cpumask(cs); | |
2193 | if (mems_updated && !nodes_empty(cs->mems_allowed)) | |
2194 | update_tasks_nodemask(cs); | |
2195 | ||
2196 | is_empty = cpumask_empty(cs->cpus_allowed) || | |
2197 | nodes_empty(cs->mems_allowed); | |
2198 | ||
2199 | mutex_unlock(&cpuset_mutex); | |
2200 | ||
2201 | /* | |
2202 | * Move tasks to the nearest ancestor with execution resources, | |
2203 | * This is full cgroup operation which will also call back into | |
2204 | * cpuset. Should be done outside any lock. | |
2205 | */ | |
2206 | if (is_empty) | |
2207 | remove_tasks_in_empty_cpuset(cs); | |
2208 | ||
2209 | mutex_lock(&cpuset_mutex); | |
2210 | } | |
2211 | ||
2212 | static void | |
2213 | hotplug_update_tasks(struct cpuset *cs, | |
2214 | struct cpumask *new_cpus, nodemask_t *new_mems, | |
2215 | bool cpus_updated, bool mems_updated) | |
2216 | { | |
2217 | if (cpumask_empty(new_cpus)) | |
2218 | cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus); | |
2219 | if (nodes_empty(*new_mems)) | |
2220 | *new_mems = parent_cs(cs)->effective_mems; | |
2221 | ||
2222 | spin_lock_irq(&callback_lock); | |
2223 | cpumask_copy(cs->effective_cpus, new_cpus); | |
2224 | cs->effective_mems = *new_mems; | |
2225 | spin_unlock_irq(&callback_lock); | |
2226 | ||
2227 | if (cpus_updated) | |
2228 | update_tasks_cpumask(cs); | |
2229 | if (mems_updated) | |
2230 | update_tasks_nodemask(cs); | |
2231 | } | |
2232 | ||
2233 | /** | |
2234 | * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug | |
2235 | * @cs: cpuset in interest | |
2236 | * | |
2237 | * Compare @cs's cpu and mem masks against top_cpuset and if some have gone | |
2238 | * offline, update @cs accordingly. If @cs ends up with no CPU or memory, | |
2239 | * all its tasks are moved to the nearest ancestor with both resources. | |
2240 | */ | |
2241 | static void cpuset_hotplug_update_tasks(struct cpuset *cs) | |
2242 | { | |
2243 | static cpumask_t new_cpus; | |
2244 | static nodemask_t new_mems; | |
2245 | bool cpus_updated; | |
2246 | bool mems_updated; | |
2247 | retry: | |
2248 | wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); | |
2249 | ||
2250 | mutex_lock(&cpuset_mutex); | |
2251 | ||
2252 | /* | |
2253 | * We have raced with task attaching. We wait until attaching | |
2254 | * is finished, so we won't attach a task to an empty cpuset. | |
2255 | */ | |
2256 | if (cs->attach_in_progress) { | |
2257 | mutex_unlock(&cpuset_mutex); | |
2258 | goto retry; | |
2259 | } | |
2260 | ||
2261 | cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus); | |
2262 | nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems); | |
2263 | ||
2264 | cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); | |
2265 | mems_updated = !nodes_equal(new_mems, cs->effective_mems); | |
2266 | ||
2267 | if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) | |
2268 | hotplug_update_tasks(cs, &new_cpus, &new_mems, | |
2269 | cpus_updated, mems_updated); | |
2270 | else | |
2271 | hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, | |
2272 | cpus_updated, mems_updated); | |
2273 | ||
2274 | mutex_unlock(&cpuset_mutex); | |
2275 | } | |
2276 | ||
2277 | /** | |
2278 | * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset | |
2279 | * | |
2280 | * This function is called after either CPU or memory configuration has | |
2281 | * changed and updates cpuset accordingly. The top_cpuset is always | |
2282 | * synchronized to cpu_active_mask and N_MEMORY, which is necessary in | |
2283 | * order to make cpusets transparent (of no affect) on systems that are | |
2284 | * actively using CPU hotplug but making no active use of cpusets. | |
2285 | * | |
2286 | * Non-root cpusets are only affected by offlining. If any CPUs or memory | |
2287 | * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on | |
2288 | * all descendants. | |
2289 | * | |
2290 | * Note that CPU offlining during suspend is ignored. We don't modify | |
2291 | * cpusets across suspend/resume cycles at all. | |
2292 | */ | |
2293 | static void cpuset_hotplug_workfn(struct work_struct *work) | |
2294 | { | |
2295 | static cpumask_t new_cpus; | |
2296 | static nodemask_t new_mems; | |
2297 | bool cpus_updated, mems_updated; | |
2298 | bool on_dfl = cgroup_subsys_on_dfl(cpuset_cgrp_subsys); | |
2299 | ||
2300 | mutex_lock(&cpuset_mutex); | |
2301 | ||
2302 | /* fetch the available cpus/mems and find out which changed how */ | |
2303 | cpumask_copy(&new_cpus, cpu_active_mask); | |
2304 | new_mems = node_states[N_MEMORY]; | |
2305 | ||
2306 | cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); | |
2307 | mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); | |
2308 | ||
2309 | /* synchronize cpus_allowed to cpu_active_mask */ | |
2310 | if (cpus_updated) { | |
2311 | spin_lock_irq(&callback_lock); | |
2312 | if (!on_dfl) | |
2313 | cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); | |
2314 | cpumask_copy(top_cpuset.effective_cpus, &new_cpus); | |
2315 | spin_unlock_irq(&callback_lock); | |
2316 | /* we don't mess with cpumasks of tasks in top_cpuset */ | |
2317 | } | |
2318 | ||
2319 | /* synchronize mems_allowed to N_MEMORY */ | |
2320 | if (mems_updated) { | |
2321 | spin_lock_irq(&callback_lock); | |
2322 | if (!on_dfl) | |
2323 | top_cpuset.mems_allowed = new_mems; | |
2324 | top_cpuset.effective_mems = new_mems; | |
2325 | spin_unlock_irq(&callback_lock); | |
2326 | update_tasks_nodemask(&top_cpuset); | |
2327 | } | |
2328 | ||
2329 | mutex_unlock(&cpuset_mutex); | |
2330 | ||
2331 | /* if cpus or mems changed, we need to propagate to descendants */ | |
2332 | if (cpus_updated || mems_updated) { | |
2333 | struct cpuset *cs; | |
2334 | struct cgroup_subsys_state *pos_css; | |
2335 | ||
2336 | rcu_read_lock(); | |
2337 | cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { | |
2338 | if (cs == &top_cpuset || !css_tryget_online(&cs->css)) | |
2339 | continue; | |
2340 | rcu_read_unlock(); | |
2341 | ||
2342 | cpuset_hotplug_update_tasks(cs); | |
2343 | ||
2344 | rcu_read_lock(); | |
2345 | css_put(&cs->css); | |
2346 | } | |
2347 | rcu_read_unlock(); | |
2348 | } | |
2349 | ||
2350 | /* rebuild sched domains if cpus_allowed has changed */ | |
2351 | if (cpus_updated) | |
2352 | rebuild_sched_domains(); | |
2353 | } | |
2354 | ||
2355 | void cpuset_update_active_cpus(bool cpu_online) | |
2356 | { | |
2357 | /* | |
2358 | * We're inside cpu hotplug critical region which usually nests | |
2359 | * inside cgroup synchronization. Bounce actual hotplug processing | |
2360 | * to a work item to avoid reverse locking order. | |
2361 | * | |
2362 | * We still need to do partition_sched_domains() synchronously; | |
2363 | * otherwise, the scheduler will get confused and put tasks to the | |
2364 | * dead CPU. Fall back to the default single domain. | |
2365 | * cpuset_hotplug_workfn() will rebuild it as necessary. | |
2366 | */ | |
2367 | partition_sched_domains(1, NULL, NULL); | |
2368 | schedule_work(&cpuset_hotplug_work); | |
2369 | } | |
2370 | ||
2371 | /* | |
2372 | * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. | |
2373 | * Call this routine anytime after node_states[N_MEMORY] changes. | |
2374 | * See cpuset_update_active_cpus() for CPU hotplug handling. | |
2375 | */ | |
2376 | static int cpuset_track_online_nodes(struct notifier_block *self, | |
2377 | unsigned long action, void *arg) | |
2378 | { | |
2379 | schedule_work(&cpuset_hotplug_work); | |
2380 | return NOTIFY_OK; | |
2381 | } | |
2382 | ||
2383 | static struct notifier_block cpuset_track_online_nodes_nb = { | |
2384 | .notifier_call = cpuset_track_online_nodes, | |
2385 | .priority = 10, /* ??! */ | |
2386 | }; | |
2387 | ||
2388 | /** | |
2389 | * cpuset_init_smp - initialize cpus_allowed | |
2390 | * | |
2391 | * Description: Finish top cpuset after cpu, node maps are initialized | |
2392 | */ | |
2393 | void __init cpuset_init_smp(void) | |
2394 | { | |
2395 | cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); | |
2396 | top_cpuset.mems_allowed = node_states[N_MEMORY]; | |
2397 | top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; | |
2398 | ||
2399 | cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask); | |
2400 | top_cpuset.effective_mems = node_states[N_MEMORY]; | |
2401 | ||
2402 | register_hotmemory_notifier(&cpuset_track_online_nodes_nb); | |
2403 | ||
2404 | cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0); | |
2405 | BUG_ON(!cpuset_migrate_mm_wq); | |
2406 | } | |
2407 | ||
2408 | /** | |
2409 | * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. | |
2410 | * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. | |
2411 | * @pmask: pointer to struct cpumask variable to receive cpus_allowed set. | |
2412 | * | |
2413 | * Description: Returns the cpumask_var_t cpus_allowed of the cpuset | |
2414 | * attached to the specified @tsk. Guaranteed to return some non-empty | |
2415 | * subset of cpu_online_mask, even if this means going outside the | |
2416 | * tasks cpuset. | |
2417 | **/ | |
2418 | ||
2419 | void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) | |
2420 | { | |
2421 | unsigned long flags; | |
2422 | ||
2423 | spin_lock_irqsave(&callback_lock, flags); | |
2424 | rcu_read_lock(); | |
2425 | guarantee_online_cpus(task_cs(tsk), pmask); | |
2426 | rcu_read_unlock(); | |
2427 | spin_unlock_irqrestore(&callback_lock, flags); | |
2428 | } | |
2429 | ||
2430 | void cpuset_cpus_allowed_fallback(struct task_struct *tsk) | |
2431 | { | |
2432 | rcu_read_lock(); | |
2433 | do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus); | |
2434 | rcu_read_unlock(); | |
2435 | ||
2436 | /* | |
2437 | * We own tsk->cpus_allowed, nobody can change it under us. | |
2438 | * | |
2439 | * But we used cs && cs->cpus_allowed lockless and thus can | |
2440 | * race with cgroup_attach_task() or update_cpumask() and get | |
2441 | * the wrong tsk->cpus_allowed. However, both cases imply the | |
2442 | * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() | |
2443 | * which takes task_rq_lock(). | |
2444 | * | |
2445 | * If we are called after it dropped the lock we must see all | |
2446 | * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary | |
2447 | * set any mask even if it is not right from task_cs() pov, | |
2448 | * the pending set_cpus_allowed_ptr() will fix things. | |
2449 | * | |
2450 | * select_fallback_rq() will fix things ups and set cpu_possible_mask | |
2451 | * if required. | |
2452 | */ | |
2453 | } | |
2454 | ||
2455 | void __init cpuset_init_current_mems_allowed(void) | |
2456 | { | |
2457 | nodes_setall(current->mems_allowed); | |
2458 | } | |
2459 | ||
2460 | /** | |
2461 | * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. | |
2462 | * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. | |
2463 | * | |
2464 | * Description: Returns the nodemask_t mems_allowed of the cpuset | |
2465 | * attached to the specified @tsk. Guaranteed to return some non-empty | |
2466 | * subset of node_states[N_MEMORY], even if this means going outside the | |
2467 | * tasks cpuset. | |
2468 | **/ | |
2469 | ||
2470 | nodemask_t cpuset_mems_allowed(struct task_struct *tsk) | |
2471 | { | |
2472 | nodemask_t mask; | |
2473 | unsigned long flags; | |
2474 | ||
2475 | spin_lock_irqsave(&callback_lock, flags); | |
2476 | rcu_read_lock(); | |
2477 | guarantee_online_mems(task_cs(tsk), &mask); | |
2478 | rcu_read_unlock(); | |
2479 | spin_unlock_irqrestore(&callback_lock, flags); | |
2480 | ||
2481 | return mask; | |
2482 | } | |
2483 | ||
2484 | /** | |
2485 | * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed | |
2486 | * @nodemask: the nodemask to be checked | |
2487 | * | |
2488 | * Are any of the nodes in the nodemask allowed in current->mems_allowed? | |
2489 | */ | |
2490 | int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) | |
2491 | { | |
2492 | return nodes_intersects(*nodemask, current->mems_allowed); | |
2493 | } | |
2494 | ||
2495 | /* | |
2496 | * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or | |
2497 | * mem_hardwall ancestor to the specified cpuset. Call holding | |
2498 | * callback_lock. If no ancestor is mem_exclusive or mem_hardwall | |
2499 | * (an unusual configuration), then returns the root cpuset. | |
2500 | */ | |
2501 | static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) | |
2502 | { | |
2503 | while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs)) | |
2504 | cs = parent_cs(cs); | |
2505 | return cs; | |
2506 | } | |
2507 | ||
2508 | /** | |
2509 | * cpuset_node_allowed - Can we allocate on a memory node? | |
2510 | * @node: is this an allowed node? | |
2511 | * @gfp_mask: memory allocation flags | |
2512 | * | |
2513 | * If we're in interrupt, yes, we can always allocate. If @node is set in | |
2514 | * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this | |
2515 | * node is set in the nearest hardwalled cpuset ancestor to current's cpuset, | |
2516 | * yes. If current has access to memory reserves due to TIF_MEMDIE, yes. | |
2517 | * Otherwise, no. | |
2518 | * | |
2519 | * GFP_USER allocations are marked with the __GFP_HARDWALL bit, | |
2520 | * and do not allow allocations outside the current tasks cpuset | |
2521 | * unless the task has been OOM killed as is marked TIF_MEMDIE. | |
2522 | * GFP_KERNEL allocations are not so marked, so can escape to the | |
2523 | * nearest enclosing hardwalled ancestor cpuset. | |
2524 | * | |
2525 | * Scanning up parent cpusets requires callback_lock. The | |
2526 | * __alloc_pages() routine only calls here with __GFP_HARDWALL bit | |
2527 | * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the | |
2528 | * current tasks mems_allowed came up empty on the first pass over | |
2529 | * the zonelist. So only GFP_KERNEL allocations, if all nodes in the | |
2530 | * cpuset are short of memory, might require taking the callback_lock. | |
2531 | * | |
2532 | * The first call here from mm/page_alloc:get_page_from_freelist() | |
2533 | * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, | |
2534 | * so no allocation on a node outside the cpuset is allowed (unless | |
2535 | * in interrupt, of course). | |
2536 | * | |
2537 | * The second pass through get_page_from_freelist() doesn't even call | |
2538 | * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() | |
2539 | * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set | |
2540 | * in alloc_flags. That logic and the checks below have the combined | |
2541 | * affect that: | |
2542 | * in_interrupt - any node ok (current task context irrelevant) | |
2543 | * GFP_ATOMIC - any node ok | |
2544 | * TIF_MEMDIE - any node ok | |
2545 | * GFP_KERNEL - any node in enclosing hardwalled cpuset ok | |
2546 | * GFP_USER - only nodes in current tasks mems allowed ok. | |
2547 | */ | |
2548 | bool __cpuset_node_allowed(int node, gfp_t gfp_mask) | |
2549 | { | |
2550 | struct cpuset *cs; /* current cpuset ancestors */ | |
2551 | int allowed; /* is allocation in zone z allowed? */ | |
2552 | unsigned long flags; | |
2553 | ||
2554 | if (in_interrupt()) | |
2555 | return true; | |
2556 | if (node_isset(node, current->mems_allowed)) | |
2557 | return true; | |
2558 | /* | |
2559 | * Allow tasks that have access to memory reserves because they have | |
2560 | * been OOM killed to get memory anywhere. | |
2561 | */ | |
2562 | if (unlikely(test_thread_flag(TIF_MEMDIE))) | |
2563 | return true; | |
2564 | if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ | |
2565 | return false; | |
2566 | ||
2567 | if (current->flags & PF_EXITING) /* Let dying task have memory */ | |
2568 | return true; | |
2569 | ||
2570 | /* Not hardwall and node outside mems_allowed: scan up cpusets */ | |
2571 | spin_lock_irqsave(&callback_lock, flags); | |
2572 | ||
2573 | rcu_read_lock(); | |
2574 | cs = nearest_hardwall_ancestor(task_cs(current)); | |
2575 | allowed = node_isset(node, cs->mems_allowed); | |
2576 | rcu_read_unlock(); | |
2577 | ||
2578 | spin_unlock_irqrestore(&callback_lock, flags); | |
2579 | return allowed; | |
2580 | } | |
2581 | ||
2582 | /** | |
2583 | * cpuset_mem_spread_node() - On which node to begin search for a file page | |
2584 | * cpuset_slab_spread_node() - On which node to begin search for a slab page | |
2585 | * | |
2586 | * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for | |
2587 | * tasks in a cpuset with is_spread_page or is_spread_slab set), | |
2588 | * and if the memory allocation used cpuset_mem_spread_node() | |
2589 | * to determine on which node to start looking, as it will for | |
2590 | * certain page cache or slab cache pages such as used for file | |
2591 | * system buffers and inode caches, then instead of starting on the | |
2592 | * local node to look for a free page, rather spread the starting | |
2593 | * node around the tasks mems_allowed nodes. | |
2594 | * | |
2595 | * We don't have to worry about the returned node being offline | |
2596 | * because "it can't happen", and even if it did, it would be ok. | |
2597 | * | |
2598 | * The routines calling guarantee_online_mems() are careful to | |
2599 | * only set nodes in task->mems_allowed that are online. So it | |
2600 | * should not be possible for the following code to return an | |
2601 | * offline node. But if it did, that would be ok, as this routine | |
2602 | * is not returning the node where the allocation must be, only | |
2603 | * the node where the search should start. The zonelist passed to | |
2604 | * __alloc_pages() will include all nodes. If the slab allocator | |
2605 | * is passed an offline node, it will fall back to the local node. | |
2606 | * See kmem_cache_alloc_node(). | |
2607 | */ | |
2608 | ||
2609 | static int cpuset_spread_node(int *rotor) | |
2610 | { | |
2611 | return *rotor = next_node_in(*rotor, current->mems_allowed); | |
2612 | } | |
2613 | ||
2614 | int cpuset_mem_spread_node(void) | |
2615 | { | |
2616 | if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE) | |
2617 | current->cpuset_mem_spread_rotor = | |
2618 | node_random(¤t->mems_allowed); | |
2619 | ||
2620 | return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); | |
2621 | } | |
2622 | ||
2623 | int cpuset_slab_spread_node(void) | |
2624 | { | |
2625 | if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE) | |
2626 | current->cpuset_slab_spread_rotor = | |
2627 | node_random(¤t->mems_allowed); | |
2628 | ||
2629 | return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); | |
2630 | } | |
2631 | ||
2632 | EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); | |
2633 | ||
2634 | /** | |
2635 | * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? | |
2636 | * @tsk1: pointer to task_struct of some task. | |
2637 | * @tsk2: pointer to task_struct of some other task. | |
2638 | * | |
2639 | * Description: Return true if @tsk1's mems_allowed intersects the | |
2640 | * mems_allowed of @tsk2. Used by the OOM killer to determine if | |
2641 | * one of the task's memory usage might impact the memory available | |
2642 | * to the other. | |
2643 | **/ | |
2644 | ||
2645 | int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, | |
2646 | const struct task_struct *tsk2) | |
2647 | { | |
2648 | return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); | |
2649 | } | |
2650 | ||
2651 | /** | |
2652 | * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed | |
2653 | * | |
2654 | * Description: Prints current's name, cpuset name, and cached copy of its | |
2655 | * mems_allowed to the kernel log. | |
2656 | */ | |
2657 | void cpuset_print_current_mems_allowed(void) | |
2658 | { | |
2659 | struct cgroup *cgrp; | |
2660 | ||
2661 | rcu_read_lock(); | |
2662 | ||
2663 | cgrp = task_cs(current)->css.cgroup; | |
2664 | pr_info("%s cpuset=", current->comm); | |
2665 | pr_cont_cgroup_name(cgrp); | |
2666 | pr_cont(" mems_allowed=%*pbl\n", | |
2667 | nodemask_pr_args(¤t->mems_allowed)); | |
2668 | ||
2669 | rcu_read_unlock(); | |
2670 | } | |
2671 | ||
2672 | /* | |
2673 | * Collection of memory_pressure is suppressed unless | |
2674 | * this flag is enabled by writing "1" to the special | |
2675 | * cpuset file 'memory_pressure_enabled' in the root cpuset. | |
2676 | */ | |
2677 | ||
2678 | int cpuset_memory_pressure_enabled __read_mostly; | |
2679 | ||
2680 | /** | |
2681 | * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. | |
2682 | * | |
2683 | * Keep a running average of the rate of synchronous (direct) | |
2684 | * page reclaim efforts initiated by tasks in each cpuset. | |
2685 | * | |
2686 | * This represents the rate at which some task in the cpuset | |
2687 | * ran low on memory on all nodes it was allowed to use, and | |
2688 | * had to enter the kernels page reclaim code in an effort to | |
2689 | * create more free memory by tossing clean pages or swapping | |
2690 | * or writing dirty pages. | |
2691 | * | |
2692 | * Display to user space in the per-cpuset read-only file | |
2693 | * "memory_pressure". Value displayed is an integer | |
2694 | * representing the recent rate of entry into the synchronous | |
2695 | * (direct) page reclaim by any task attached to the cpuset. | |
2696 | **/ | |
2697 | ||
2698 | void __cpuset_memory_pressure_bump(void) | |
2699 | { | |
2700 | rcu_read_lock(); | |
2701 | fmeter_markevent(&task_cs(current)->fmeter); | |
2702 | rcu_read_unlock(); | |
2703 | } | |
2704 | ||
2705 | #ifdef CONFIG_PROC_PID_CPUSET | |
2706 | /* | |
2707 | * proc_cpuset_show() | |
2708 | * - Print tasks cpuset path into seq_file. | |
2709 | * - Used for /proc/<pid>/cpuset. | |
2710 | * - No need to task_lock(tsk) on this tsk->cpuset reference, as it | |
2711 | * doesn't really matter if tsk->cpuset changes after we read it, | |
2712 | * and we take cpuset_mutex, keeping cpuset_attach() from changing it | |
2713 | * anyway. | |
2714 | */ | |
2715 | int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, | |
2716 | struct pid *pid, struct task_struct *tsk) | |
2717 | { | |
2718 | char *buf; | |
2719 | struct cgroup_subsys_state *css; | |
2720 | int retval; | |
2721 | ||
2722 | retval = -ENOMEM; | |
2723 | buf = kmalloc(PATH_MAX, GFP_KERNEL); | |
2724 | if (!buf) | |
2725 | goto out; | |
2726 | ||
2727 | css = task_get_css(tsk, cpuset_cgrp_id); | |
2728 | retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX, | |
2729 | current->nsproxy->cgroup_ns); | |
2730 | css_put(css); | |
2731 | if (retval >= PATH_MAX) | |
2732 | retval = -ENAMETOOLONG; | |
2733 | if (retval < 0) | |
2734 | goto out_free; | |
2735 | seq_puts(m, buf); | |
2736 | seq_putc(m, '\n'); | |
2737 | retval = 0; | |
2738 | out_free: | |
2739 | kfree(buf); | |
2740 | out: | |
2741 | return retval; | |
2742 | } | |
2743 | #endif /* CONFIG_PROC_PID_CPUSET */ | |
2744 | ||
2745 | /* Display task mems_allowed in /proc/<pid>/status file. */ | |
2746 | void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) | |
2747 | { | |
2748 | seq_printf(m, "Mems_allowed:\t%*pb\n", | |
2749 | nodemask_pr_args(&task->mems_allowed)); | |
2750 | seq_printf(m, "Mems_allowed_list:\t%*pbl\n", | |
2751 | nodemask_pr_args(&task->mems_allowed)); | |
2752 | } |