1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_CGROUP_H
3#define _LINUX_CGROUP_H
4/*
5 * cgroup interface
6 *
7 * Copyright (C) 2003 BULL SA
8 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
9 *
10 */
11
12#include <linux/sched.h>
13#include <linux/cpumask.h>
14#include <linux/nodemask.h>
15#include <linux/rculist.h>
16#include <linux/cgroupstats.h>
17#include <linux/fs.h>
18#include <linux/seq_file.h>
19#include <linux/kernfs.h>
20#include <linux/jump_label.h>
21#include <linux/types.h>
22#include <linux/ns_common.h>
23#include <linux/nsproxy.h>
24#include <linux/user_namespace.h>
25#include <linux/refcount.h>
26#include <linux/kernel_stat.h>
27
28#include <linux/cgroup-defs.h>
29
30struct kernel_clone_args;
31
32#ifdef CONFIG_CGROUPS
33
34/*
35 * All weight knobs on the default hierarchy should use the following min,
36 * default and max values. The default value is the logarithmic center of
37 * MIN and MAX and allows 100x to be expressed in both directions.
38 */
39#define CGROUP_WEIGHT_MIN 1
40#define CGROUP_WEIGHT_DFL 100
41#define CGROUP_WEIGHT_MAX 10000
42
43/* walk only threadgroup leaders */
44#define CSS_TASK_ITER_PROCS (1U << 0)
45/* walk all threaded css_sets in the domain */
46#define CSS_TASK_ITER_THREADED (1U << 1)
47
48/* internal flags */
49#define CSS_TASK_ITER_SKIPPED (1U << 16)
50
51/* a css_task_iter should be treated as an opaque object */
52struct css_task_iter {
53 struct cgroup_subsys *ss;
54 unsigned int flags;
55
56 struct list_head *cset_pos;
57 struct list_head *cset_head;
58
59 struct list_head *tcset_pos;
60 struct list_head *tcset_head;
61
62 struct list_head *task_pos;
63
64 struct list_head *cur_tasks_head;
65 struct css_set *cur_cset;
66 struct css_set *cur_dcset;
67 struct task_struct *cur_task;
68 struct list_head iters_node; /* css_set->task_iters */
69};
70
71extern struct cgroup_root cgrp_dfl_root;
72extern struct css_set init_css_set;
73
74#define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
75#include <linux/cgroup_subsys.h>
76#undef SUBSYS
77
78#define SUBSYS(_x) \
79 extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \
80 extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
81#include <linux/cgroup_subsys.h>
82#undef SUBSYS
83
84/**
85 * cgroup_subsys_enabled - fast test on whether a subsys is enabled
86 * @ss: subsystem in question
87 */
88#define cgroup_subsys_enabled(ss) \
89 static_branch_likely(&ss ## _enabled_key)
90
91/**
92 * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
93 * @ss: subsystem in question
94 */
95#define cgroup_subsys_on_dfl(ss) \
96 static_branch_likely(&ss ## _on_dfl_key)
97
98bool css_has_online_children(struct cgroup_subsys_state *css);
99struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
100struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup,
101 struct cgroup_subsys *ss);
102struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
103 struct cgroup_subsys *ss);
104struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
105 struct cgroup_subsys *ss);
106
107struct cgroup *cgroup_get_from_path(const char *path);
108struct cgroup *cgroup_get_from_fd(int fd);
109
110int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
111int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
112
113int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
114int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
115int cgroup_rm_cftypes(struct cftype *cfts);
116void cgroup_file_notify(struct cgroup_file *cfile);
117
118int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
119int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
120int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
121 struct pid *pid, struct task_struct *tsk);
122
123void cgroup_fork(struct task_struct *p);
124extern int cgroup_can_fork(struct task_struct *p,
125 struct kernel_clone_args *kargs);
126extern void cgroup_cancel_fork(struct task_struct *p,
127 struct kernel_clone_args *kargs);
128extern void cgroup_post_fork(struct task_struct *p,
129 struct kernel_clone_args *kargs);
130void cgroup_exit(struct task_struct *p);
131void cgroup_release(struct task_struct *p);
132void cgroup_free(struct task_struct *p);
133
134int cgroup_init_early(void);
135int cgroup_init(void);
136
137int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
138
139/*
140 * Iteration helpers and macros.
141 */
142
143struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
144 struct cgroup_subsys_state *parent);
145struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
146 struct cgroup_subsys_state *css);
147struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
148struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
149 struct cgroup_subsys_state *css);
150
151struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
152 struct cgroup_subsys_state **dst_cssp);
153struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
154 struct cgroup_subsys_state **dst_cssp);
155
156void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
157 struct css_task_iter *it);
158struct task_struct *css_task_iter_next(struct css_task_iter *it);
159void css_task_iter_end(struct css_task_iter *it);
160
161/**
162 * css_for_each_child - iterate through children of a css
163 * @pos: the css * to use as the loop cursor
164 * @parent: css whose children to walk
165 *
166 * Walk @parent's children. Must be called under rcu_read_lock().
167 *
168 * If a subsystem synchronizes ->css_online() and the start of iteration, a
169 * css which finished ->css_online() is guaranteed to be visible in the
170 * future iterations and will stay visible until the last reference is put.
171 * A css which hasn't finished ->css_online() or already finished
172 * ->css_offline() may show up during traversal. It's each subsystem's
173 * responsibility to synchronize against on/offlining.
174 *
175 * It is allowed to temporarily drop RCU read lock during iteration. The
176 * caller is responsible for ensuring that @pos remains accessible until
177 * the start of the next iteration by, for example, bumping the css refcnt.
178 */
179#define css_for_each_child(pos, parent) \
180 for ((pos) = css_next_child(NULL, (parent)); (pos); \
181 (pos) = css_next_child((pos), (parent)))
182
183/**
184 * css_for_each_descendant_pre - pre-order walk of a css's descendants
185 * @pos: the css * to use as the loop cursor
186 * @root: css whose descendants to walk
187 *
188 * Walk @root's descendants. @root is included in the iteration and the
189 * first node to be visited. Must be called under rcu_read_lock().
190 *
191 * If a subsystem synchronizes ->css_online() and the start of iteration, a
192 * css which finished ->css_online() is guaranteed to be visible in the
193 * future iterations and will stay visible until the last reference is put.
194 * A css which hasn't finished ->css_online() or already finished
195 * ->css_offline() may show up during traversal. It's each subsystem's
196 * responsibility to synchronize against on/offlining.
197 *
198 * For example, the following guarantees that a descendant can't escape
199 * state updates of its ancestors.
200 *
201 * my_online(@css)
202 * {
203 * Lock @css's parent and @css;
204 * Inherit state from the parent;
205 * Unlock both.
206 * }
207 *
208 * my_update_state(@css)
209 * {
210 * css_for_each_descendant_pre(@pos, @css) {
211 * Lock @pos;
212 * if (@pos == @css)
213 * Update @css's state;
214 * else
215 * Verify @pos is alive and inherit state from its parent;
216 * Unlock @pos;
217 * }
218 * }
219 *
220 * As long as the inheriting step, including checking the parent state, is
221 * enclosed inside @pos locking, double-locking the parent isn't necessary
222 * while inheriting. The state update to the parent is guaranteed to be
223 * visible by walking order and, as long as inheriting operations to the
224 * same @pos are atomic to each other, multiple updates racing each other
225 * still result in the correct state. It's guaranateed that at least one
226 * inheritance happens for any css after the latest update to its parent.
227 *
228 * If checking parent's state requires locking the parent, each inheriting
229 * iteration should lock and unlock both @pos->parent and @pos.
230 *
231 * Alternatively, a subsystem may choose to use a single global lock to
232 * synchronize ->css_online() and ->css_offline() against tree-walking
233 * operations.
234 *
235 * It is allowed to temporarily drop RCU read lock during iteration. The
236 * caller is responsible for ensuring that @pos remains accessible until
237 * the start of the next iteration by, for example, bumping the css refcnt.
238 */
239#define css_for_each_descendant_pre(pos, css) \
240 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \
241 (pos) = css_next_descendant_pre((pos), (css)))
242
243/**
244 * css_for_each_descendant_post - post-order walk of a css's descendants
245 * @pos: the css * to use as the loop cursor
246 * @css: css whose descendants to walk
247 *
248 * Similar to css_for_each_descendant_pre() but performs post-order
249 * traversal instead. @root is included in the iteration and the last
250 * node to be visited.
251 *
252 * If a subsystem synchronizes ->css_online() and the start of iteration, a
253 * css which finished ->css_online() is guaranteed to be visible in the
254 * future iterations and will stay visible until the last reference is put.
255 * A css which hasn't finished ->css_online() or already finished
256 * ->css_offline() may show up during traversal. It's each subsystem's
257 * responsibility to synchronize against on/offlining.
258 *
259 * Note that the walk visibility guarantee example described in pre-order
260 * walk doesn't apply the same to post-order walks.
261 */
262#define css_for_each_descendant_post(pos, css) \
263 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
264 (pos) = css_next_descendant_post((pos), (css)))
265
266/**
267 * cgroup_taskset_for_each - iterate cgroup_taskset
268 * @task: the loop cursor
269 * @dst_css: the destination css
270 * @tset: taskset to iterate
271 *
272 * @tset may contain multiple tasks and they may belong to multiple
273 * processes.
274 *
275 * On the v2 hierarchy, there may be tasks from multiple processes and they
276 * may not share the source or destination csses.
277 *
278 * On traditional hierarchies, when there are multiple tasks in @tset, if a
279 * task of a process is in @tset, all tasks of the process are in @tset.
280 * Also, all are guaranteed to share the same source and destination csses.
281 *
282 * Iteration is not in any specific order.
283 */
284#define cgroup_taskset_for_each(task, dst_css, tset) \
285 for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
286 (task); \
287 (task) = cgroup_taskset_next((tset), &(dst_css)))
288
289/**
290 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
291 * @leader: the loop cursor
292 * @dst_css: the destination css
293 * @tset: taskset to iterate
294 *
295 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset
296 * may not contain any.
297 */
298#define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
299 for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
300 (leader); \
301 (leader) = cgroup_taskset_next((tset), &(dst_css))) \
302 if ((leader) != (leader)->group_leader) \
303 ; \
304 else
305
306/*
307 * Inline functions.
308 */
309
310static inline u64 cgroup_id(const struct cgroup *cgrp)
311{
312 return cgrp->kn->id;
313}
314
315/**
316 * css_get - obtain a reference on the specified css
317 * @css: target css
318 *
319 * The caller must already have a reference.
320 */
321static inline void css_get(struct cgroup_subsys_state *css)
322{
323 if (!(css->flags & CSS_NO_REF))
324 percpu_ref_get(&css->refcnt);
325}
326
327/**
328 * css_get_many - obtain references on the specified css
329 * @css: target css
330 * @n: number of references to get
331 *
332 * The caller must already have a reference.
333 */
334static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
335{
336 if (!(css->flags & CSS_NO_REF))
337 percpu_ref_get_many(&css->refcnt, n);
338}
339
340/**
341 * css_tryget - try to obtain a reference on the specified css
342 * @css: target css
343 *
344 * Obtain a reference on @css unless it already has reached zero and is
345 * being released. This function doesn't care whether @css is on or
346 * offline. The caller naturally needs to ensure that @css is accessible
347 * but doesn't have to be holding a reference on it - IOW, RCU protected
348 * access is good enough for this function. Returns %true if a reference
349 * count was successfully obtained; %false otherwise.
350 */
351static inline bool css_tryget(struct cgroup_subsys_state *css)
352{
353 if (!(css->flags & CSS_NO_REF))
354 return percpu_ref_tryget(&css->refcnt);
355 return true;
356}
357
358/**
359 * css_tryget_online - try to obtain a reference on the specified css if online
360 * @css: target css
361 *
362 * Obtain a reference on @css if it's online. The caller naturally needs
363 * to ensure that @css is accessible but doesn't have to be holding a
364 * reference on it - IOW, RCU protected access is good enough for this
365 * function. Returns %true if a reference count was successfully obtained;
366 * %false otherwise.
367 */
368static inline bool css_tryget_online(struct cgroup_subsys_state *css)
369{
370 if (!(css->flags & CSS_NO_REF))
371 return percpu_ref_tryget_live(&css->refcnt);
372 return true;
373}
374
375/**
376 * css_is_dying - test whether the specified css is dying
377 * @css: target css
378 *
379 * Test whether @css is in the process of offlining or already offline. In
380 * most cases, ->css_online() and ->css_offline() callbacks should be
381 * enough; however, the actual offline operations are RCU delayed and this
382 * test returns %true also when @css is scheduled to be offlined.
383 *
384 * This is useful, for example, when the use case requires synchronous
385 * behavior with respect to cgroup removal. cgroup removal schedules css
386 * offlining but the css can seem alive while the operation is being
387 * delayed. If the delay affects user visible semantics, this test can be
388 * used to resolve the situation.
389 */
390static inline bool css_is_dying(struct cgroup_subsys_state *css)
391{
392 return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
393}
394
395/**
396 * css_put - put a css reference
397 * @css: target css
398 *
399 * Put a reference obtained via css_get() and css_tryget_online().
400 */
401static inline void css_put(struct cgroup_subsys_state *css)
402{
403 if (!(css->flags & CSS_NO_REF))
404 percpu_ref_put(&css->refcnt);
405}
406
407/**
408 * css_put_many - put css references
409 * @css: target css
410 * @n: number of references to put
411 *
412 * Put references obtained via css_get() and css_tryget_online().
413 */
414static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
415{
416 if (!(css->flags & CSS_NO_REF))
417 percpu_ref_put_many(&css->refcnt, n);
418}
419
420static inline void cgroup_get(struct cgroup *cgrp)
421{
422 css_get(&cgrp->self);
423}
424
425static inline bool cgroup_tryget(struct cgroup *cgrp)
426{
427 return css_tryget(&cgrp->self);
428}
429
430static inline void cgroup_put(struct cgroup *cgrp)
431{
432 css_put(&cgrp->self);
433}
434
435/**
436 * task_css_set_check - obtain a task's css_set with extra access conditions
437 * @task: the task to obtain css_set for
438 * @__c: extra condition expression to be passed to rcu_dereference_check()
439 *
440 * A task's css_set is RCU protected, initialized and exited while holding
441 * task_lock(), and can only be modified while holding both cgroup_mutex
442 * and task_lock() while the task is alive. This macro verifies that the
443 * caller is inside proper critical section and returns @task's css_set.
444 *
445 * The caller can also specify additional allowed conditions via @__c, such
446 * as locks used during the cgroup_subsys::attach() methods.
447 */
448#ifdef CONFIG_PROVE_RCU
449extern struct mutex cgroup_mutex;
450extern spinlock_t css_set_lock;
451#define task_css_set_check(task, __c) \
452 rcu_dereference_check((task)->cgroups, \
453 rcu_read_lock_sched_held() || \
454 lockdep_is_held(&cgroup_mutex) || \
455 lockdep_is_held(&css_set_lock) || \
456 ((task)->flags & PF_EXITING) || (__c))
457#else
458#define task_css_set_check(task, __c) \
459 rcu_dereference((task)->cgroups)
460#endif
461
462/**
463 * task_css_check - obtain css for (task, subsys) w/ extra access conds
464 * @task: the target task
465 * @subsys_id: the target subsystem ID
466 * @__c: extra condition expression to be passed to rcu_dereference_check()
467 *
468 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
469 * synchronization rules are the same as task_css_set_check().
470 */
471#define task_css_check(task, subsys_id, __c) \
472 task_css_set_check((task), (__c))->subsys[(subsys_id)]
473
474/**
475 * task_css_set - obtain a task's css_set
476 * @task: the task to obtain css_set for
477 *
478 * See task_css_set_check().
479 */
480static inline struct css_set *task_css_set(struct task_struct *task)
481{
482 return task_css_set_check(task, false);
483}
484
485/**
486 * task_css - obtain css for (task, subsys)
487 * @task: the target task
488 * @subsys_id: the target subsystem ID
489 *
490 * See task_css_check().
491 */
492static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
493 int subsys_id)
494{
495 return task_css_check(task, subsys_id, false);
496}
497
498/**
499 * task_get_css - find and get the css for (task, subsys)
500 * @task: the target task
501 * @subsys_id: the target subsystem ID
502 *
503 * Find the css for the (@task, @subsys_id) combination, increment a
504 * reference on and return it. This function is guaranteed to return a
505 * valid css. The returned css may already have been offlined.
506 */
507static inline struct cgroup_subsys_state *
508task_get_css(struct task_struct *task, int subsys_id)
509{
510 struct cgroup_subsys_state *css;
511
512 rcu_read_lock();
513 while (true) {
514 css = task_css(task, subsys_id);
515 /*
516 * Can't use css_tryget_online() here. A task which has
517 * PF_EXITING set may stay associated with an offline css.
518 * If such task calls this function, css_tryget_online()
519 * will keep failing.
520 */
521 if (likely(css_tryget(css)))
522 break;
523 cpu_relax();
524 }
525 rcu_read_unlock();
526 return css;
527}
528
529/**
530 * task_css_is_root - test whether a task belongs to the root css
531 * @task: the target task
532 * @subsys_id: the target subsystem ID
533 *
534 * Test whether @task belongs to the root css on the specified subsystem.
535 * May be invoked in any context.
536 */
537static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
538{
539 return task_css_check(task, subsys_id, true) ==
540 init_css_set.subsys[subsys_id];
541}
542
543static inline struct cgroup *task_cgroup(struct task_struct *task,
544 int subsys_id)
545{
546 return task_css(task, subsys_id)->cgroup;
547}
548
549static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
550{
551 return task_css_set(task)->dfl_cgrp;
552}
553
554static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
555{
556 struct cgroup_subsys_state *parent_css = cgrp->self.parent;
557
558 if (parent_css)
559 return container_of(parent_css, struct cgroup, self);
560 return NULL;
561}
562
563/**
564 * cgroup_is_descendant - test ancestry
565 * @cgrp: the cgroup to be tested
566 * @ancestor: possible ancestor of @cgrp
567 *
568 * Test whether @cgrp is a descendant of @ancestor. It also returns %true
569 * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
570 * and @ancestor are accessible.
571 */
572static inline bool cgroup_is_descendant(struct cgroup *cgrp,
573 struct cgroup *ancestor)
574{
575 if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
576 return false;
577 return cgrp->ancestor_ids[ancestor->level] == cgroup_id(ancestor);
578}
579
580/**
581 * cgroup_ancestor - find ancestor of cgroup
582 * @cgrp: cgroup to find ancestor of
583 * @ancestor_level: level of ancestor to find starting from root
584 *
585 * Find ancestor of cgroup at specified level starting from root if it exists
586 * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
587 * @ancestor_level.
588 *
589 * This function is safe to call as long as @cgrp is accessible.
590 */
591static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
592 int ancestor_level)
593{
594 if (cgrp->level < ancestor_level)
595 return NULL;
596 while (cgrp && cgrp->level > ancestor_level)
597 cgrp = cgroup_parent(cgrp);
598 return cgrp;
599}
600
601/**
602 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
603 * @task: the task to be tested
604 * @ancestor: possible ancestor of @task's cgroup
605 *
606 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
607 * It follows all the same rules as cgroup_is_descendant, and only applies
608 * to the default hierarchy.
609 */
610static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
611 struct cgroup *ancestor)
612{
613 struct css_set *cset = task_css_set(task);
614
615 return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
616}
617
618/* no synchronization, the result can only be used as a hint */
619static inline bool cgroup_is_populated(struct cgroup *cgrp)
620{
621 return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
622 cgrp->nr_populated_threaded_children;
623}
624
625/* returns ino associated with a cgroup */
626static inline ino_t cgroup_ino(struct cgroup *cgrp)
627{
628 return kernfs_ino(cgrp->kn);
629}
630
631/* cft/css accessors for cftype->write() operation */
632static inline struct cftype *of_cft(struct kernfs_open_file *of)
633{
634 return of->kn->priv;
635}
636
637struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
638
639/* cft/css accessors for cftype->seq_*() operations */
640static inline struct cftype *seq_cft(struct seq_file *seq)
641{
642 return of_cft(seq->private);
643}
644
645static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
646{
647 return of_css(seq->private);
648}
649
650/*
651 * Name / path handling functions. All are thin wrappers around the kernfs
652 * counterparts and can be called under any context.
653 */
654
655static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
656{
657 return kernfs_name(cgrp->kn, buf, buflen);
658}
659
660static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
661{
662 return kernfs_path(cgrp->kn, buf, buflen);
663}
664
665static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
666{
667 pr_cont_kernfs_name(cgrp->kn);
668}
669
670static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
671{
672 pr_cont_kernfs_path(cgrp->kn);
673}
674
675static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
676{
677 return cgrp->psi;
678}
679
680bool cgroup_psi_enabled(void);
681
682static inline void cgroup_init_kthreadd(void)
683{
684 /*
685 * kthreadd is inherited by all kthreads, keep it in the root so
686 * that the new kthreads are guaranteed to stay in the root until
687 * initialization is finished.
688 */
689 current->no_cgroup_migration = 1;
690}
691
692static inline void cgroup_kthread_ready(void)
693{
694 /*
695 * This kthread finished initialization. The creator should have
696 * set PF_NO_SETAFFINITY if this kthread should stay in the root.
697 */
698 current->no_cgroup_migration = 0;
699}
700
701void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
702struct cgroup *cgroup_get_from_id(u64 id);
703#else /* !CONFIG_CGROUPS */
704
705struct cgroup_subsys_state;
706struct cgroup;
707
708static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }
709static inline void css_get(struct cgroup_subsys_state *css) {}
710static inline void css_put(struct cgroup_subsys_state *css) {}
711static inline int cgroup_attach_task_all(struct task_struct *from,
712 struct task_struct *t) { return 0; }
713static inline int cgroupstats_build(struct cgroupstats *stats,
714 struct dentry *dentry) { return -EINVAL; }
715
716static inline void cgroup_fork(struct task_struct *p) {}
717static inline int cgroup_can_fork(struct task_struct *p,
718 struct kernel_clone_args *kargs) { return 0; }
719static inline void cgroup_cancel_fork(struct task_struct *p,
720 struct kernel_clone_args *kargs) {}
721static inline void cgroup_post_fork(struct task_struct *p,
722 struct kernel_clone_args *kargs) {}
723static inline void cgroup_exit(struct task_struct *p) {}
724static inline void cgroup_release(struct task_struct *p) {}
725static inline void cgroup_free(struct task_struct *p) {}
726
727static inline int cgroup_init_early(void) { return 0; }
728static inline int cgroup_init(void) { return 0; }
729static inline void cgroup_init_kthreadd(void) {}
730static inline void cgroup_kthread_ready(void) {}
731
732static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
733{
734 return NULL;
735}
736
737static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
738{
739 return NULL;
740}
741
742static inline bool cgroup_psi_enabled(void)
743{
744 return false;
745}
746
747static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
748 struct cgroup *ancestor)
749{
750 return true;
751}
752
753static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
754{}
755
756static inline struct cgroup *cgroup_get_from_id(u64 id)
757{
758 return NULL;
759}
760#endif /* !CONFIG_CGROUPS */
761
762#ifdef CONFIG_CGROUPS
763/*
764 * cgroup scalable recursive statistics.
765 */
766void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
767void cgroup_rstat_flush(struct cgroup *cgrp);
768void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
769void cgroup_rstat_flush_hold(struct cgroup *cgrp);
770void cgroup_rstat_flush_release(void);
771
772/*
773 * Basic resource stats.
774 */
775#ifdef CONFIG_CGROUP_CPUACCT
776void cpuacct_charge(struct task_struct *tsk, u64 cputime);
777void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
778#else
779static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
780static inline void cpuacct_account_field(struct task_struct *tsk, int index,
781 u64 val) {}
782#endif
783
784void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
785void __cgroup_account_cputime_field(struct cgroup *cgrp,
786 enum cpu_usage_stat index, u64 delta_exec);
787
788static inline void cgroup_account_cputime(struct task_struct *task,
789 u64 delta_exec)
790{
791 struct cgroup *cgrp;
792
793 cpuacct_charge(task, delta_exec);
794
795 cgrp = task_dfl_cgroup(task);
796 if (cgroup_parent(cgrp))
797 __cgroup_account_cputime(cgrp, delta_exec);
798}
799
800static inline void cgroup_account_cputime_field(struct task_struct *task,
801 enum cpu_usage_stat index,
802 u64 delta_exec)
803{
804 struct cgroup *cgrp;
805
806 cpuacct_account_field(task, index, delta_exec);
807
808 cgrp = task_dfl_cgroup(task);
809 if (cgroup_parent(cgrp))
810 __cgroup_account_cputime_field(cgrp, index, delta_exec);
811}
812
813#else /* CONFIG_CGROUPS */
814
815static inline void cgroup_account_cputime(struct task_struct *task,
816 u64 delta_exec) {}
817static inline void cgroup_account_cputime_field(struct task_struct *task,
818 enum cpu_usage_stat index,
819 u64 delta_exec) {}
820
821#endif /* CONFIG_CGROUPS */
822
823/*
824 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
825 * definition in cgroup-defs.h.
826 */
827#ifdef CONFIG_SOCK_CGROUP_DATA
828
829void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
830void cgroup_sk_clone(struct sock_cgroup_data *skcd);
831void cgroup_sk_free(struct sock_cgroup_data *skcd);
832
833static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
834{
835 return skcd->cgroup;
836}
837
838#else /* CONFIG_CGROUP_DATA */
839
840static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
841static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
842static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
843
844#endif /* CONFIG_CGROUP_DATA */
845
846struct cgroup_namespace {
847 struct ns_common ns;
848 struct user_namespace *user_ns;
849 struct ucounts *ucounts;
850 struct css_set *root_cset;
851};
852
853extern struct cgroup_namespace init_cgroup_ns;
854
855#ifdef CONFIG_CGROUPS
856
857void free_cgroup_ns(struct cgroup_namespace *ns);
858
859struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
860 struct user_namespace *user_ns,
861 struct cgroup_namespace *old_ns);
862
863int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
864 struct cgroup_namespace *ns);
865
866#else /* !CONFIG_CGROUPS */
867
868static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
869static inline struct cgroup_namespace *
870copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
871 struct cgroup_namespace *old_ns)
872{
873 return old_ns;
874}
875
876#endif /* !CONFIG_CGROUPS */
877
878static inline void get_cgroup_ns(struct cgroup_namespace *ns)
879{
880 if (ns)
881 refcount_inc(&ns->ns.count);
882}
883
884static inline void put_cgroup_ns(struct cgroup_namespace *ns)
885{
886 if (ns && refcount_dec_and_test(&ns->ns.count))
887 free_cgroup_ns(ns);
888}
889
890#ifdef CONFIG_CGROUPS
891
892void cgroup_enter_frozen(void);
893void cgroup_leave_frozen(bool always_leave);
894void cgroup_update_frozen(struct cgroup *cgrp);
895void cgroup_freeze(struct cgroup *cgrp, bool freeze);
896void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
897 struct cgroup *dst);
898
899static inline bool cgroup_task_frozen(struct task_struct *task)
900{
901 return task->frozen;
902}
903
904#else /* !CONFIG_CGROUPS */
905
906static inline void cgroup_enter_frozen(void) { }
907static inline void cgroup_leave_frozen(bool always_leave) { }
908static inline bool cgroup_task_frozen(struct task_struct *task)
909{
910 return false;
911}
912
913#endif /* !CONFIG_CGROUPS */
914
915#ifdef CONFIG_CGROUP_BPF
916static inline void cgroup_bpf_get(struct cgroup *cgrp)
917{
918 percpu_ref_get(&cgrp->bpf.refcnt);
919}
920
921static inline void cgroup_bpf_put(struct cgroup *cgrp)
922{
923 percpu_ref_put(&cgrp->bpf.refcnt);
924}
925
926#else /* CONFIG_CGROUP_BPF */
927
928static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
929static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
930
931#endif /* CONFIG_CGROUP_BPF */
932
933#endif /* _LINUX_CGROUP_H */
934

source code of linux/include/linux/cgroup.h