1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * linux/cgroup-defs.h - basic definitions for cgroup
4 *
5 * This file provides basic type and interface. Include this file directly
6 * only if necessary to avoid cyclic dependencies.
7 */
8 #ifndef _LINUX_CGROUP_DEFS_H
9 #define _LINUX_CGROUP_DEFS_H
10
11 #include <linux/limits.h>
12 #include <linux/list.h>
13 #include <linux/idr.h>
14 #include <linux/wait.h>
15 #include <linux/mutex.h>
16 #include <linux/rcupdate.h>
17 #include <linux/refcount.h>
18 #include <linux/percpu-refcount.h>
19 #include <linux/percpu-rwsem.h>
20 #include <linux/u64_stats_sync.h>
21 #include <linux/workqueue.h>
22 #include <linux/bpf-cgroup-defs.h>
23 #include <linux/psi_types.h>
24
25 #ifdef CONFIG_CGROUPS
26
27 struct cgroup;
28 struct cgroup_root;
29 struct cgroup_subsys;
30 struct cgroup_taskset;
31 struct kernfs_node;
32 struct kernfs_ops;
33 struct kernfs_open_file;
34 struct seq_file;
35 struct poll_table_struct;
36
37 #define MAX_CGROUP_TYPE_NAMELEN 32
38 #define MAX_CGROUP_ROOT_NAMELEN 64
39 #define MAX_CFTYPE_NAME 64
40
41 /* define the enumeration of all cgroup subsystems */
42 #define SUBSYS(_x) _x ## _cgrp_id,
43 enum cgroup_subsys_id {
44 #include <linux/cgroup_subsys.h>
45 CGROUP_SUBSYS_COUNT,
46 };
47 #undef SUBSYS
48
49 /* bits in struct cgroup_subsys_state flags field */
50 enum {
51 CSS_NO_REF = (1 << 0), /* no reference counting for this css */
52 CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */
53 CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */
54 CSS_VISIBLE = (1 << 3), /* css is visible to userland */
55 CSS_DYING = (1 << 4), /* css is dying */
56 };
57
58 /* bits in struct cgroup flags field */
59 enum {
60 /* Control Group requires release notifications to userspace */
61 CGRP_NOTIFY_ON_RELEASE,
62 /*
63 * Clone the parent's configuration when creating a new child
64 * cpuset cgroup. For historical reasons, this option can be
65 * specified at mount time and thus is implemented here.
66 */
67 CGRP_CPUSET_CLONE_CHILDREN,
68
69 /* Control group has to be frozen. */
70 CGRP_FREEZE,
71
72 /* Cgroup is frozen. */
73 CGRP_FROZEN,
74
75 /* Control group has to be killed. */
76 CGRP_KILL,
77 };
78
79 /* cgroup_root->flags */
80 enum {
81 CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */
82 CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */
83
84 /*
85 * Consider namespaces as delegation boundaries. If this flag is
86 * set, controller specific interface files in a namespace root
87 * aren't writeable from inside the namespace.
88 */
89 CGRP_ROOT_NS_DELEGATE = (1 << 3),
90
91 /*
92 * Reduce latencies on dynamic cgroup modifications such as task
93 * migrations and controller on/offs by disabling percpu operation on
94 * cgroup_threadgroup_rwsem. This makes hot path operations such as
95 * forks and exits into the slow path and more expensive.
96 *
97 * The static usage pattern of creating a cgroup, enabling controllers,
98 * and then seeding it with CLONE_INTO_CGROUP doesn't require write
99 * locking cgroup_threadgroup_rwsem and thus doesn't benefit from
100 * favordynmod.
101 */
102 CGRP_ROOT_FAVOR_DYNMODS = (1 << 4),
103
104 /*
105 * Enable cpuset controller in v1 cgroup to use v2 behavior.
106 */
107 CGRP_ROOT_CPUSET_V2_MODE = (1 << 16),
108
109 /*
110 * Enable legacy local memory.events.
111 */
112 CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 17),
113
114 /*
115 * Enable recursive subtree protection
116 */
117 CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18),
118
119 /*
120 * Enable hugetlb accounting for the memory controller.
121 */
122 CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING = (1 << 19),
123
124 /*
125 * Enable legacy local pids.events.
126 */
127 CGRP_ROOT_PIDS_LOCAL_EVENTS = (1 << 20),
128 };
129
130 /* cftype->flags */
131 enum {
132 CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */
133 CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */
134 CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */
135
136 CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */
137 CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */
138 CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */
139
140 /* internal flags, do not use outside cgroup core proper */
141 __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */
142 __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */
143 __CFTYPE_ADDED = (1 << 18),
144 };
145
146 /*
147 * cgroup_file is the handle for a file instance created in a cgroup which
148 * is used, for example, to generate file changed notifications. This can
149 * be obtained by setting cftype->file_offset.
150 */
151 struct cgroup_file {
152 /* do not access any fields from outside cgroup core */
153 struct kernfs_node *kn;
154 unsigned long notified_at;
155 struct timer_list notify_timer;
156 };
157
158 /*
159 * Per-subsystem/per-cgroup state maintained by the system. This is the
160 * fundamental structural building block that controllers deal with.
161 *
162 * Fields marked with "PI:" are public and immutable and may be accessed
163 * directly without synchronization.
164 */
165 struct cgroup_subsys_state {
166 /* PI: the cgroup that this css is attached to */
167 struct cgroup *cgroup;
168
169 /* PI: the cgroup subsystem that this css is attached to */
170 struct cgroup_subsys *ss;
171
172 /* reference count - access via css_[try]get() and css_put() */
173 struct percpu_ref refcnt;
174
175 /*
176 * siblings list anchored at the parent's ->children
177 *
178 * linkage is protected by cgroup_mutex or RCU
179 */
180 struct list_head sibling;
181 struct list_head children;
182
183 /* flush target list anchored at cgrp->rstat_css_list */
184 struct list_head rstat_css_node;
185
186 /*
187 * PI: Subsys-unique ID. 0 is unused and root is always 1. The
188 * matching css can be looked up using css_from_id().
189 */
190 int id;
191
192 unsigned int flags;
193
194 /*
195 * Monotonically increasing unique serial number which defines a
196 * uniform order among all csses. It's guaranteed that all
197 * ->children lists are in the ascending order of ->serial_nr and
198 * used to allow interrupting and resuming iterations.
199 */
200 u64 serial_nr;
201
202 /*
203 * Incremented by online self and children. Used to guarantee that
204 * parents are not offlined before their children.
205 */
206 atomic_t online_cnt;
207
208 /* percpu_ref killing and RCU release */
209 struct work_struct destroy_work;
210 struct rcu_work destroy_rwork;
211
212 /*
213 * PI: the parent css. Placed here for cache proximity to following
214 * fields of the containing structure.
215 */
216 struct cgroup_subsys_state *parent;
217
218 /*
219 * Keep track of total numbers of visible descendant CSSes.
220 * The total number of dying CSSes is tracked in
221 * css->cgroup->nr_dying_subsys[ssid].
222 * Protected by cgroup_mutex.
223 */
224 int nr_descendants;
225 };
226
227 /*
228 * A css_set is a structure holding pointers to a set of
229 * cgroup_subsys_state objects. This saves space in the task struct
230 * object and speeds up fork()/exit(), since a single inc/dec and a
231 * list_add()/del() can bump the reference count on the entire cgroup
232 * set for a task.
233 */
234 struct css_set {
235 /*
236 * Set of subsystem states, one for each subsystem. This array is
237 * immutable after creation apart from the init_css_set during
238 * subsystem registration (at boot time).
239 */
240 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
241
242 /* reference count */
243 refcount_t refcount;
244
245 /*
246 * For a domain cgroup, the following points to self. If threaded,
247 * to the matching cset of the nearest domain ancestor. The
248 * dom_cset provides access to the domain cgroup and its csses to
249 * which domain level resource consumptions should be charged.
250 */
251 struct css_set *dom_cset;
252
253 /* the default cgroup associated with this css_set */
254 struct cgroup *dfl_cgrp;
255
256 /* internal task count, protected by css_set_lock */
257 int nr_tasks;
258
259 /*
260 * Lists running through all tasks using this cgroup group.
261 * mg_tasks lists tasks which belong to this cset but are in the
262 * process of being migrated out or in. Protected by
263 * css_set_lock, but, during migration, once tasks are moved to
264 * mg_tasks, it can be read safely while holding cgroup_mutex.
265 */
266 struct list_head tasks;
267 struct list_head mg_tasks;
268 struct list_head dying_tasks;
269
270 /* all css_task_iters currently walking this cset */
271 struct list_head task_iters;
272
273 /*
274 * On the default hierarchy, ->subsys[ssid] may point to a css
275 * attached to an ancestor instead of the cgroup this css_set is
276 * associated with. The following node is anchored at
277 * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to
278 * iterate through all css's attached to a given cgroup.
279 */
280 struct list_head e_cset_node[CGROUP_SUBSYS_COUNT];
281
282 /* all threaded csets whose ->dom_cset points to this cset */
283 struct list_head threaded_csets;
284 struct list_head threaded_csets_node;
285
286 /*
287 * List running through all cgroup groups in the same hash
288 * slot. Protected by css_set_lock
289 */
290 struct hlist_node hlist;
291
292 /*
293 * List of cgrp_cset_links pointing at cgroups referenced from this
294 * css_set. Protected by css_set_lock.
295 */
296 struct list_head cgrp_links;
297
298 /*
299 * List of csets participating in the on-going migration either as
300 * source or destination. Protected by cgroup_mutex.
301 */
302 struct list_head mg_src_preload_node;
303 struct list_head mg_dst_preload_node;
304 struct list_head mg_node;
305
306 /*
307 * If this cset is acting as the source of migration the following
308 * two fields are set. mg_src_cgrp and mg_dst_cgrp are
309 * respectively the source and destination cgroups of the on-going
310 * migration. mg_dst_cset is the destination cset the target tasks
311 * on this cset should be migrated to. Protected by cgroup_mutex.
312 */
313 struct cgroup *mg_src_cgrp;
314 struct cgroup *mg_dst_cgrp;
315 struct css_set *mg_dst_cset;
316
317 /* dead and being drained, ignore for migration */
318 bool dead;
319
320 /* For RCU-protected deletion */
321 struct rcu_head rcu_head;
322 };
323
324 struct cgroup_base_stat {
325 struct task_cputime cputime;
326
327 #ifdef CONFIG_SCHED_CORE
328 u64 forceidle_sum;
329 #endif
330 };
331
332 /*
333 * rstat - cgroup scalable recursive statistics. Accounting is done
334 * per-cpu in cgroup_rstat_cpu which is then lazily propagated up the
335 * hierarchy on reads.
336 *
337 * When a stat gets updated, the cgroup_rstat_cpu and its ancestors are
338 * linked into the updated tree. On the following read, propagation only
339 * considers and consumes the updated tree. This makes reading O(the
340 * number of descendants which have been active since last read) instead of
341 * O(the total number of descendants).
342 *
343 * This is important because there can be a lot of (draining) cgroups which
344 * aren't active and stat may be read frequently. The combination can
345 * become very expensive. By propagating selectively, increasing reading
346 * frequency decreases the cost of each read.
347 *
348 * This struct hosts both the fields which implement the above -
349 * updated_children and updated_next - and the fields which track basic
350 * resource statistics on top of it - bsync, bstat and last_bstat.
351 */
352 struct cgroup_rstat_cpu {
353 /*
354 * ->bsync protects ->bstat. These are the only fields which get
355 * updated in the hot path.
356 */
357 struct u64_stats_sync bsync;
358 struct cgroup_base_stat bstat;
359
360 /*
361 * Snapshots at the last reading. These are used to calculate the
362 * deltas to propagate to the global counters.
363 */
364 struct cgroup_base_stat last_bstat;
365
366 /*
367 * This field is used to record the cumulative per-cpu time of
368 * the cgroup and its descendants. Currently it can be read via
369 * eBPF/drgn etc, and we are still trying to determine how to
370 * expose it in the cgroupfs interface.
371 */
372 struct cgroup_base_stat subtree_bstat;
373
374 /*
375 * Snapshots at the last reading. These are used to calculate the
376 * deltas to propagate to the per-cpu subtree_bstat.
377 */
378 struct cgroup_base_stat last_subtree_bstat;
379
380 /*
381 * Child cgroups with stat updates on this cpu since the last read
382 * are linked on the parent's ->updated_children through
383 * ->updated_next.
384 *
385 * In addition to being more compact, singly-linked list pointing
386 * to the cgroup makes it unnecessary for each per-cpu struct to
387 * point back to the associated cgroup.
388 *
389 * Protected by per-cpu cgroup_rstat_cpu_lock.
390 */
391 struct cgroup *updated_children; /* terminated by self cgroup */
392 struct cgroup *updated_next; /* NULL iff not on the list */
393 };
394
395 struct cgroup_freezer_state {
396 /* Should the cgroup and its descendants be frozen. */
397 bool freeze;
398
399 /* Should the cgroup actually be frozen? */
400 int e_freeze;
401
402 /* Fields below are protected by css_set_lock */
403
404 /* Number of frozen descendant cgroups */
405 int nr_frozen_descendants;
406
407 /*
408 * Number of tasks, which are counted as frozen:
409 * frozen, SIGSTOPped, and PTRACEd.
410 */
411 int nr_frozen_tasks;
412 };
413
414 struct cgroup {
415 /* self css with NULL ->ss, points back to this cgroup */
416 struct cgroup_subsys_state self;
417
418 unsigned long flags; /* "unsigned long" so bitops work */
419
420 /*
421 * The depth this cgroup is at. The root is at depth zero and each
422 * step down the hierarchy increments the level. This along with
423 * ancestors[] can determine whether a given cgroup is a
424 * descendant of another without traversing the hierarchy.
425 */
426 int level;
427
428 /* Maximum allowed descent tree depth */
429 int max_depth;
430
431 /*
432 * Keep track of total numbers of visible and dying descent cgroups.
433 * Dying cgroups are cgroups which were deleted by a user,
434 * but are still existing because someone else is holding a reference.
435 * max_descendants is a maximum allowed number of descent cgroups.
436 *
437 * nr_descendants and nr_dying_descendants are protected
438 * by cgroup_mutex and css_set_lock. It's fine to read them holding
439 * any of cgroup_mutex and css_set_lock; for writing both locks
440 * should be held.
441 */
442 int nr_descendants;
443 int nr_dying_descendants;
444 int max_descendants;
445
446 /*
447 * Each non-empty css_set associated with this cgroup contributes
448 * one to nr_populated_csets. The counter is zero iff this cgroup
449 * doesn't have any tasks.
450 *
451 * All children which have non-zero nr_populated_csets and/or
452 * nr_populated_children of their own contribute one to either
453 * nr_populated_domain_children or nr_populated_threaded_children
454 * depending on their type. Each counter is zero iff all cgroups
455 * of the type in the subtree proper don't have any tasks.
456 */
457 int nr_populated_csets;
458 int nr_populated_domain_children;
459 int nr_populated_threaded_children;
460
461 int nr_threaded_children; /* # of live threaded child cgroups */
462
463 struct kernfs_node *kn; /* cgroup kernfs entry */
464 struct cgroup_file procs_file; /* handle for "cgroup.procs" */
465 struct cgroup_file events_file; /* handle for "cgroup.events" */
466
467 /* handles for "{cpu,memory,io,irq}.pressure" */
468 struct cgroup_file psi_files[NR_PSI_RESOURCES];
469
470 /*
471 * The bitmask of subsystems enabled on the child cgroups.
472 * ->subtree_control is the one configured through
473 * "cgroup.subtree_control" while ->subtree_ss_mask is the effective
474 * one which may have more subsystems enabled. Controller knobs
475 * are made available iff it's enabled in ->subtree_control.
476 */
477 u16 subtree_control;
478 u16 subtree_ss_mask;
479 u16 old_subtree_control;
480 u16 old_subtree_ss_mask;
481
482 /* Private pointers for each registered subsystem */
483 struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT];
484
485 /*
486 * Keep track of total number of dying CSSes at and below this cgroup.
487 * Protected by cgroup_mutex.
488 */
489 int nr_dying_subsys[CGROUP_SUBSYS_COUNT];
490
491 struct cgroup_root *root;
492
493 /*
494 * List of cgrp_cset_links pointing at css_sets with tasks in this
495 * cgroup. Protected by css_set_lock.
496 */
497 struct list_head cset_links;
498
499 /*
500 * On the default hierarchy, a css_set for a cgroup with some
501 * susbsys disabled will point to css's which are associated with
502 * the closest ancestor which has the subsys enabled. The
503 * following lists all css_sets which point to this cgroup's css
504 * for the given subsystem.
505 */
506 struct list_head e_csets[CGROUP_SUBSYS_COUNT];
507
508 /*
509 * If !threaded, self. If threaded, it points to the nearest
510 * domain ancestor. Inside a threaded subtree, cgroups are exempt
511 * from process granularity and no-internal-task constraint.
512 * Domain level resource consumptions which aren't tied to a
513 * specific task are charged to the dom_cgrp.
514 */
515 struct cgroup *dom_cgrp;
516 struct cgroup *old_dom_cgrp; /* used while enabling threaded */
517
518 /* per-cpu recursive resource statistics */
519 struct cgroup_rstat_cpu __percpu *rstat_cpu;
520 struct list_head rstat_css_list;
521
522 /*
523 * Add padding to separate the read mostly rstat_cpu and
524 * rstat_css_list into a different cacheline from the following
525 * rstat_flush_next and *bstat fields which can have frequent updates.
526 */
527 CACHELINE_PADDING(_pad_);
528
529 /*
530 * A singly-linked list of cgroup structures to be rstat flushed.
531 * This is a scratch field to be used exclusively by
532 * cgroup_rstat_flush_locked() and protected by cgroup_rstat_lock.
533 */
534 struct cgroup *rstat_flush_next;
535
536 /* cgroup basic resource statistics */
537 struct cgroup_base_stat last_bstat;
538 struct cgroup_base_stat bstat;
539 struct prev_cputime prev_cputime; /* for printing out cputime */
540
541 /*
542 * list of pidlists, up to two for each namespace (one for procs, one
543 * for tasks); created on demand.
544 */
545 struct list_head pidlists;
546 struct mutex pidlist_mutex;
547
548 /* used to wait for offlining of csses */
549 wait_queue_head_t offline_waitq;
550
551 /* used to schedule release agent */
552 struct work_struct release_agent_work;
553
554 /* used to track pressure stalls */
555 struct psi_group *psi;
556
557 /* used to store eBPF programs */
558 struct cgroup_bpf bpf;
559
560 /* Used to store internal freezer state */
561 struct cgroup_freezer_state freezer;
562
563 #ifdef CONFIG_BPF_SYSCALL
564 struct bpf_local_storage __rcu *bpf_cgrp_storage;
565 #endif
566
567 /* All ancestors including self */
568 struct cgroup *ancestors[];
569 };
570
571 /*
572 * A cgroup_root represents the root of a cgroup hierarchy, and may be
573 * associated with a kernfs_root to form an active hierarchy. This is
574 * internal to cgroup core. Don't access directly from controllers.
575 */
576 struct cgroup_root {
577 struct kernfs_root *kf_root;
578
579 /* The bitmask of subsystems attached to this hierarchy */
580 unsigned int subsys_mask;
581
582 /* Unique id for this hierarchy. */
583 int hierarchy_id;
584
585 /* A list running through the active hierarchies */
586 struct list_head root_list;
587 struct rcu_head rcu; /* Must be near the top */
588
589 /*
590 * The root cgroup. The containing cgroup_root will be destroyed on its
591 * release. cgrp->ancestors[0] will be used overflowing into the
592 * following field. cgrp_ancestor_storage must immediately follow.
593 */
594 struct cgroup cgrp;
595
596 /* must follow cgrp for cgrp->ancestors[0], see above */
597 struct cgroup *cgrp_ancestor_storage;
598
599 /* Number of cgroups in the hierarchy, used only for /proc/cgroups */
600 atomic_t nr_cgrps;
601
602 /* Hierarchy-specific flags */
603 unsigned int flags;
604
605 /* The path to use for release notifications. */
606 char release_agent_path[PATH_MAX];
607
608 /* The name for this hierarchy - may be empty */
609 char name[MAX_CGROUP_ROOT_NAMELEN];
610 };
611
612 /*
613 * struct cftype: handler definitions for cgroup control files
614 *
615 * When reading/writing to a file:
616 * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata
617 * - the 'cftype' of the file is file->f_path.dentry->d_fsdata
618 */
619 struct cftype {
620 /*
621 * By convention, the name should begin with the name of the
622 * subsystem, followed by a period. Zero length string indicates
623 * end of cftype array.
624 */
625 char name[MAX_CFTYPE_NAME];
626 unsigned long private;
627
628 /*
629 * The maximum length of string, excluding trailing nul, that can
630 * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed.
631 */
632 size_t max_write_len;
633
634 /* CFTYPE_* flags */
635 unsigned int flags;
636
637 /*
638 * If non-zero, should contain the offset from the start of css to
639 * a struct cgroup_file field. cgroup will record the handle of
640 * the created file into it. The recorded handle can be used as
641 * long as the containing css remains accessible.
642 */
643 unsigned int file_offset;
644
645 /*
646 * Fields used for internal bookkeeping. Initialized automatically
647 * during registration.
648 */
649 struct cgroup_subsys *ss; /* NULL for cgroup core files */
650 struct list_head node; /* anchored at ss->cfts */
651 struct kernfs_ops *kf_ops;
652
653 int (*open)(struct kernfs_open_file *of);
654 void (*release)(struct kernfs_open_file *of);
655
656 /*
657 * read_u64() is a shortcut for the common case of returning a
658 * single integer. Use it in place of read()
659 */
660 u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft);
661 /*
662 * read_s64() is a signed version of read_u64()
663 */
664 s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft);
665
666 /* generic seq_file read interface */
667 int (*seq_show)(struct seq_file *sf, void *v);
668
669 /* optional ops, implement all or none */
670 void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
671 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
672 void (*seq_stop)(struct seq_file *sf, void *v);
673
674 /*
675 * write_u64() is a shortcut for the common case of accepting
676 * a single integer (as parsed by simple_strtoull) from
677 * userspace. Use in place of write(); return 0 or error.
678 */
679 int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft,
680 u64 val);
681 /*
682 * write_s64() is a signed version of write_u64()
683 */
684 int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft,
685 s64 val);
686
687 /*
688 * write() is the generic write callback which maps directly to
689 * kernfs write operation and overrides all other operations.
690 * Maximum write size is determined by ->max_write_len. Use
691 * of_css/cft() to access the associated css and cft.
692 */
693 ssize_t (*write)(struct kernfs_open_file *of,
694 char *buf, size_t nbytes, loff_t off);
695
696 __poll_t (*poll)(struct kernfs_open_file *of,
697 struct poll_table_struct *pt);
698
699 struct lock_class_key lockdep_key;
700 };
701
702 /*
703 * Control Group subsystem type.
704 * See Documentation/admin-guide/cgroup-v1/cgroups.rst for details
705 */
706 struct cgroup_subsys {
707 struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css);
708 int (*css_online)(struct cgroup_subsys_state *css);
709 void (*css_offline)(struct cgroup_subsys_state *css);
710 void (*css_released)(struct cgroup_subsys_state *css);
711 void (*css_free)(struct cgroup_subsys_state *css);
712 void (*css_reset)(struct cgroup_subsys_state *css);
713 void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu);
714 int (*css_extra_stat_show)(struct seq_file *seq,
715 struct cgroup_subsys_state *css);
716 int (*css_local_stat_show)(struct seq_file *seq,
717 struct cgroup_subsys_state *css);
718
719 int (*can_attach)(struct cgroup_taskset *tset);
720 void (*cancel_attach)(struct cgroup_taskset *tset);
721 void (*attach)(struct cgroup_taskset *tset);
722 void (*post_attach)(void);
723 int (*can_fork)(struct task_struct *task,
724 struct css_set *cset);
725 void (*cancel_fork)(struct task_struct *task, struct css_set *cset);
726 void (*fork)(struct task_struct *task);
727 void (*exit)(struct task_struct *task);
728 void (*release)(struct task_struct *task);
729 void (*bind)(struct cgroup_subsys_state *root_css);
730
731 bool early_init:1;
732
733 /*
734 * If %true, the controller, on the default hierarchy, doesn't show
735 * up in "cgroup.controllers" or "cgroup.subtree_control", is
736 * implicitly enabled on all cgroups on the default hierarchy, and
737 * bypasses the "no internal process" constraint. This is for
738 * utility type controllers which is transparent to userland.
739 *
740 * An implicit controller can be stolen from the default hierarchy
741 * anytime and thus must be okay with offline csses from previous
742 * hierarchies coexisting with csses for the current one.
743 */
744 bool implicit_on_dfl:1;
745
746 /*
747 * If %true, the controller, supports threaded mode on the default
748 * hierarchy. In a threaded subtree, both process granularity and
749 * no-internal-process constraint are ignored and a threaded
750 * controllers should be able to handle that.
751 *
752 * Note that as an implicit controller is automatically enabled on
753 * all cgroups on the default hierarchy, it should also be
754 * threaded. implicit && !threaded is not supported.
755 */
756 bool threaded:1;
757
758 /* the following two fields are initialized automatically during boot */
759 int id;
760 const char *name;
761
762 /* optional, initialized automatically during boot if not set */
763 const char *legacy_name;
764
765 /* link to parent, protected by cgroup_lock() */
766 struct cgroup_root *root;
767
768 /* idr for css->id */
769 struct idr css_idr;
770
771 /*
772 * List of cftypes. Each entry is the first entry of an array
773 * terminated by zero length name.
774 */
775 struct list_head cfts;
776
777 /*
778 * Base cftypes which are automatically registered. The two can
779 * point to the same array.
780 */
781 struct cftype *dfl_cftypes; /* for the default hierarchy */
782 struct cftype *legacy_cftypes; /* for the legacy hierarchies */
783
784 /*
785 * A subsystem may depend on other subsystems. When such subsystem
786 * is enabled on a cgroup, the depended-upon subsystems are enabled
787 * together if available. Subsystems enabled due to dependency are
788 * not visible to userland until explicitly enabled. The following
789 * specifies the mask of subsystems that this one depends on.
790 */
791 unsigned int depends_on;
792 };
793
794 extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem;
795
796 struct cgroup_of_peak {
797 unsigned long value;
798 struct list_head list;
799 };
800
801 /**
802 * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups
803 * @tsk: target task
804 *
805 * Allows cgroup operations to synchronize against threadgroup changes
806 * using a percpu_rw_semaphore.
807 */
cgroup_threadgroup_change_begin(struct task_struct * tsk)808 static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
809 {
810 percpu_down_read(&cgroup_threadgroup_rwsem);
811 }
812
813 /**
814 * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups
815 * @tsk: target task
816 *
817 * Counterpart of cgroup_threadcgroup_change_begin().
818 */
cgroup_threadgroup_change_end(struct task_struct * tsk)819 static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
820 {
821 percpu_up_read(&cgroup_threadgroup_rwsem);
822 }
823
824 #else /* CONFIG_CGROUPS */
825
826 #define CGROUP_SUBSYS_COUNT 0
827
cgroup_threadgroup_change_begin(struct task_struct * tsk)828 static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
829 {
830 might_sleep();
831 }
832
cgroup_threadgroup_change_end(struct task_struct * tsk)833 static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {}
834
835 #endif /* CONFIG_CGROUPS */
836
837 #ifdef CONFIG_SOCK_CGROUP_DATA
838
839 /*
840 * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains
841 * per-socket cgroup information except for memcg association.
842 *
843 * On legacy hierarchies, net_prio and net_cls controllers directly
844 * set attributes on each sock which can then be tested by the network
845 * layer. On the default hierarchy, each sock is associated with the
846 * cgroup it was created in and the networking layer can match the
847 * cgroup directly.
848 */
849 struct sock_cgroup_data {
850 struct cgroup *cgroup; /* v2 */
851 #ifdef CONFIG_CGROUP_NET_CLASSID
852 u32 classid; /* v1 */
853 #endif
854 #ifdef CONFIG_CGROUP_NET_PRIO
855 u16 prioidx; /* v1 */
856 #endif
857 };
858
sock_cgroup_prioidx(const struct sock_cgroup_data * skcd)859 static inline u16 sock_cgroup_prioidx(const struct sock_cgroup_data *skcd)
860 {
861 #ifdef CONFIG_CGROUP_NET_PRIO
862 return READ_ONCE(skcd->prioidx);
863 #else
864 return 1;
865 #endif
866 }
867
sock_cgroup_classid(const struct sock_cgroup_data * skcd)868 static inline u32 sock_cgroup_classid(const struct sock_cgroup_data *skcd)
869 {
870 #ifdef CONFIG_CGROUP_NET_CLASSID
871 return READ_ONCE(skcd->classid);
872 #else
873 return 0;
874 #endif
875 }
876
sock_cgroup_set_prioidx(struct sock_cgroup_data * skcd,u16 prioidx)877 static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd,
878 u16 prioidx)
879 {
880 #ifdef CONFIG_CGROUP_NET_PRIO
881 WRITE_ONCE(skcd->prioidx, prioidx);
882 #endif
883 }
884
sock_cgroup_set_classid(struct sock_cgroup_data * skcd,u32 classid)885 static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd,
886 u32 classid)
887 {
888 #ifdef CONFIG_CGROUP_NET_CLASSID
889 WRITE_ONCE(skcd->classid, classid);
890 #endif
891 }
892
893 #else /* CONFIG_SOCK_CGROUP_DATA */
894
895 struct sock_cgroup_data {
896 };
897
898 #endif /* CONFIG_SOCK_CGROUP_DATA */
899
900 #endif /* _LINUX_CGROUP_DEFS_H */
901