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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
b4a04ab7 TH |
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> | |
4b9502e6 | 17 | #include <linux/refcount.h> |
b4a04ab7 | 18 | #include <linux/percpu-refcount.h> |
7d7efec3 | 19 | #include <linux/percpu-rwsem.h> |
041cd640 | 20 | #include <linux/u64_stats_sync.h> |
b4a04ab7 | 21 | #include <linux/workqueue.h> |
30070984 | 22 | #include <linux/bpf-cgroup.h> |
b4a04ab7 TH |
23 | |
24 | #ifdef CONFIG_CGROUPS | |
25 | ||
26 | struct cgroup; | |
27 | struct cgroup_root; | |
28 | struct cgroup_subsys; | |
29 | struct cgroup_taskset; | |
30 | struct kernfs_node; | |
31 | struct kernfs_ops; | |
32 | struct kernfs_open_file; | |
c80ef9e0 | 33 | struct seq_file; |
b4a04ab7 TH |
34 | |
35 | #define MAX_CGROUP_TYPE_NAMELEN 32 | |
36 | #define MAX_CGROUP_ROOT_NAMELEN 64 | |
37 | #define MAX_CFTYPE_NAME 64 | |
38 | ||
39 | /* define the enumeration of all cgroup subsystems */ | |
40 | #define SUBSYS(_x) _x ## _cgrp_id, | |
41 | enum cgroup_subsys_id { | |
42 | #include <linux/cgroup_subsys.h> | |
43 | CGROUP_SUBSYS_COUNT, | |
44 | }; | |
45 | #undef SUBSYS | |
46 | ||
47 | /* bits in struct cgroup_subsys_state flags field */ | |
48 | enum { | |
49 | CSS_NO_REF = (1 << 0), /* no reference counting for this css */ | |
50 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ | |
51 | CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ | |
88cb04b9 | 52 | CSS_VISIBLE = (1 << 3), /* css is visible to userland */ |
33c35aa4 | 53 | CSS_DYING = (1 << 4), /* css is dying */ |
b4a04ab7 TH |
54 | }; |
55 | ||
56 | /* bits in struct cgroup flags field */ | |
57 | enum { | |
58 | /* Control Group requires release notifications to userspace */ | |
59 | CGRP_NOTIFY_ON_RELEASE, | |
60 | /* | |
61 | * Clone the parent's configuration when creating a new child | |
62 | * cpuset cgroup. For historical reasons, this option can be | |
63 | * specified at mount time and thus is implemented here. | |
64 | */ | |
65 | CGRP_CPUSET_CLONE_CHILDREN, | |
66 | }; | |
67 | ||
68 | /* cgroup_root->flags */ | |
69 | enum { | |
b4a04ab7 TH |
70 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
71 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
5136f636 TH |
72 | |
73 | /* | |
74 | * Consider namespaces as delegation boundaries. If this flag is | |
75 | * set, controller specific interface files in a namespace root | |
76 | * aren't writeable from inside the namespace. | |
77 | */ | |
78 | CGRP_ROOT_NS_DELEGATE = (1 << 3), | |
e1cba4b8 WL |
79 | |
80 | /* | |
81 | * Enable cpuset controller in v1 cgroup to use v2 behavior. | |
82 | */ | |
83 | CGRP_ROOT_CPUSET_V2_MODE = (1 << 4), | |
b4a04ab7 TH |
84 | }; |
85 | ||
86 | /* cftype->flags */ | |
87 | enum { | |
88 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ | |
89 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
5136f636 TH |
90 | CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */ |
91 | ||
b4a04ab7 | 92 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
7dbdb199 | 93 | CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ |
b4a04ab7 TH |
94 | |
95 | /* internal flags, do not use outside cgroup core proper */ | |
96 | __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ | |
97 | __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ | |
98 | }; | |
99 | ||
6f60eade TH |
100 | /* |
101 | * cgroup_file is the handle for a file instance created in a cgroup which | |
102 | * is used, for example, to generate file changed notifications. This can | |
103 | * be obtained by setting cftype->file_offset. | |
104 | */ | |
105 | struct cgroup_file { | |
106 | /* do not access any fields from outside cgroup core */ | |
6f60eade TH |
107 | struct kernfs_node *kn; |
108 | }; | |
109 | ||
b4a04ab7 TH |
110 | /* |
111 | * Per-subsystem/per-cgroup state maintained by the system. This is the | |
112 | * fundamental structural building block that controllers deal with. | |
113 | * | |
114 | * Fields marked with "PI:" are public and immutable and may be accessed | |
115 | * directly without synchronization. | |
116 | */ | |
117 | struct cgroup_subsys_state { | |
118 | /* PI: the cgroup that this css is attached to */ | |
119 | struct cgroup *cgroup; | |
120 | ||
121 | /* PI: the cgroup subsystem that this css is attached to */ | |
122 | struct cgroup_subsys *ss; | |
123 | ||
124 | /* reference count - access via css_[try]get() and css_put() */ | |
125 | struct percpu_ref refcnt; | |
126 | ||
b4a04ab7 TH |
127 | /* siblings list anchored at the parent's ->children */ |
128 | struct list_head sibling; | |
129 | struct list_head children; | |
130 | ||
131 | /* | |
132 | * PI: Subsys-unique ID. 0 is unused and root is always 1. The | |
133 | * matching css can be looked up using css_from_id(). | |
134 | */ | |
135 | int id; | |
136 | ||
137 | unsigned int flags; | |
138 | ||
139 | /* | |
140 | * Monotonically increasing unique serial number which defines a | |
141 | * uniform order among all csses. It's guaranteed that all | |
142 | * ->children lists are in the ascending order of ->serial_nr and | |
143 | * used to allow interrupting and resuming iterations. | |
144 | */ | |
145 | u64 serial_nr; | |
146 | ||
aa226ff4 TH |
147 | /* |
148 | * Incremented by online self and children. Used to guarantee that | |
149 | * parents are not offlined before their children. | |
150 | */ | |
151 | atomic_t online_cnt; | |
152 | ||
b4a04ab7 TH |
153 | /* percpu_ref killing and RCU release */ |
154 | struct rcu_head rcu_head; | |
155 | struct work_struct destroy_work; | |
b8b1a2e5 TP |
156 | |
157 | /* | |
158 | * PI: the parent css. Placed here for cache proximity to following | |
159 | * fields of the containing structure. | |
160 | */ | |
161 | struct cgroup_subsys_state *parent; | |
b4a04ab7 TH |
162 | }; |
163 | ||
164 | /* | |
165 | * A css_set is a structure holding pointers to a set of | |
166 | * cgroup_subsys_state objects. This saves space in the task struct | |
167 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
168 | * list_add()/del() can bump the reference count on the entire cgroup | |
169 | * set for a task. | |
170 | */ | |
171 | struct css_set { | |
b4a04ab7 | 172 | /* |
5f617ebb TH |
173 | * Set of subsystem states, one for each subsystem. This array is |
174 | * immutable after creation apart from the init_css_set during | |
175 | * subsystem registration (at boot time). | |
b4a04ab7 | 176 | */ |
5f617ebb TH |
177 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
178 | ||
179 | /* reference count */ | |
4b9502e6 | 180 | refcount_t refcount; |
5f617ebb | 181 | |
454000ad TH |
182 | /* |
183 | * For a domain cgroup, the following points to self. If threaded, | |
184 | * to the matching cset of the nearest domain ancestor. The | |
185 | * dom_cset provides access to the domain cgroup and its csses to | |
186 | * which domain level resource consumptions should be charged. | |
187 | */ | |
188 | struct css_set *dom_cset; | |
189 | ||
5f617ebb TH |
190 | /* the default cgroup associated with this css_set */ |
191 | struct cgroup *dfl_cgrp; | |
b4a04ab7 | 192 | |
73a7242a WL |
193 | /* internal task count, protected by css_set_lock */ |
194 | int nr_tasks; | |
195 | ||
b4a04ab7 TH |
196 | /* |
197 | * Lists running through all tasks using this cgroup group. | |
198 | * mg_tasks lists tasks which belong to this cset but are in the | |
199 | * process of being migrated out or in. Protected by | |
200 | * css_set_rwsem, but, during migration, once tasks are moved to | |
201 | * mg_tasks, it can be read safely while holding cgroup_mutex. | |
202 | */ | |
203 | struct list_head tasks; | |
204 | struct list_head mg_tasks; | |
798cc880 | 205 | struct list_head dying_tasks; |
b4a04ab7 | 206 | |
5f617ebb TH |
207 | /* all css_task_iters currently walking this cset */ |
208 | struct list_head task_iters; | |
209 | ||
b4a04ab7 | 210 | /* |
5f617ebb TH |
211 | * On the default hierarhcy, ->subsys[ssid] may point to a css |
212 | * attached to an ancestor instead of the cgroup this css_set is | |
213 | * associated with. The following node is anchored at | |
214 | * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to | |
215 | * iterate through all css's attached to a given cgroup. | |
b4a04ab7 | 216 | */ |
5f617ebb | 217 | struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; |
b4a04ab7 | 218 | |
454000ad TH |
219 | /* all threaded csets whose ->dom_cset points to this cset */ |
220 | struct list_head threaded_csets; | |
221 | struct list_head threaded_csets_node; | |
222 | ||
5f617ebb TH |
223 | /* |
224 | * List running through all cgroup groups in the same hash | |
225 | * slot. Protected by css_set_lock | |
226 | */ | |
227 | struct hlist_node hlist; | |
b4a04ab7 TH |
228 | |
229 | /* | |
5f617ebb TH |
230 | * List of cgrp_cset_links pointing at cgroups referenced from this |
231 | * css_set. Protected by css_set_lock. | |
b4a04ab7 | 232 | */ |
5f617ebb | 233 | struct list_head cgrp_links; |
b4a04ab7 TH |
234 | |
235 | /* | |
236 | * List of csets participating in the on-going migration either as | |
237 | * source or destination. Protected by cgroup_mutex. | |
238 | */ | |
239 | struct list_head mg_preload_node; | |
240 | struct list_head mg_node; | |
241 | ||
242 | /* | |
243 | * If this cset is acting as the source of migration the following | |
e4857982 TH |
244 | * two fields are set. mg_src_cgrp and mg_dst_cgrp are |
245 | * respectively the source and destination cgroups of the on-going | |
246 | * migration. mg_dst_cset is the destination cset the target tasks | |
247 | * on this cset should be migrated to. Protected by cgroup_mutex. | |
b4a04ab7 TH |
248 | */ |
249 | struct cgroup *mg_src_cgrp; | |
e4857982 | 250 | struct cgroup *mg_dst_cgrp; |
b4a04ab7 TH |
251 | struct css_set *mg_dst_cset; |
252 | ||
2b021cbf TH |
253 | /* dead and being drained, ignore for migration */ |
254 | bool dead; | |
255 | ||
b4a04ab7 TH |
256 | /* For RCU-protected deletion */ |
257 | struct rcu_head rcu_head; | |
258 | }; | |
259 | ||
041cd640 TH |
260 | /* |
261 | * cgroup basic resource usage statistics. Accounting is done per-cpu in | |
262 | * cgroup_cpu_stat which is then lazily propagated up the hierarchy on | |
263 | * reads. | |
264 | * | |
265 | * When a stat gets updated, the cgroup_cpu_stat and its ancestors are | |
266 | * linked into the updated tree. On the following read, propagation only | |
267 | * considers and consumes the updated tree. This makes reading O(the | |
268 | * number of descendants which have been active since last read) instead of | |
269 | * O(the total number of descendants). | |
270 | * | |
271 | * This is important because there can be a lot of (draining) cgroups which | |
272 | * aren't active and stat may be read frequently. The combination can | |
273 | * become very expensive. By propagating selectively, increasing reading | |
274 | * frequency decreases the cost of each read. | |
275 | */ | |
276 | struct cgroup_cpu_stat { | |
277 | /* | |
278 | * ->sync protects all the current counters. These are the only | |
279 | * fields which get updated in the hot path. | |
280 | */ | |
281 | struct u64_stats_sync sync; | |
282 | struct task_cputime cputime; | |
283 | ||
284 | /* | |
285 | * Snapshots at the last reading. These are used to calculate the | |
286 | * deltas to propagate to the global counters. | |
287 | */ | |
288 | struct task_cputime last_cputime; | |
289 | ||
290 | /* | |
291 | * Child cgroups with stat updates on this cpu since the last read | |
292 | * are linked on the parent's ->updated_children through | |
293 | * ->updated_next. | |
294 | * | |
295 | * In addition to being more compact, singly-linked list pointing | |
296 | * to the cgroup makes it unnecessary for each per-cpu struct to | |
297 | * point back to the associated cgroup. | |
298 | * | |
299 | * Protected by per-cpu cgroup_cpu_stat_lock. | |
300 | */ | |
301 | struct cgroup *updated_children; /* terminated by self cgroup */ | |
302 | struct cgroup *updated_next; /* NULL iff not on the list */ | |
303 | }; | |
304 | ||
305 | struct cgroup_stat { | |
306 | /* per-cpu statistics are collected into the folowing global counters */ | |
307 | struct task_cputime cputime; | |
308 | struct prev_cputime prev_cputime; | |
309 | }; | |
310 | ||
b4a04ab7 TH |
311 | struct cgroup { |
312 | /* self css with NULL ->ss, points back to this cgroup */ | |
313 | struct cgroup_subsys_state self; | |
314 | ||
315 | unsigned long flags; /* "unsigned long" so bitops work */ | |
316 | ||
317 | /* | |
318 | * idr allocated in-hierarchy ID. | |
319 | * | |
320 | * ID 0 is not used, the ID of the root cgroup is always 1, and a | |
321 | * new cgroup will be assigned with a smallest available ID. | |
322 | * | |
323 | * Allocating/Removing ID must be protected by cgroup_mutex. | |
324 | */ | |
325 | int id; | |
326 | ||
b11cfb58 TH |
327 | /* |
328 | * The depth this cgroup is at. The root is at depth zero and each | |
329 | * step down the hierarchy increments the level. This along with | |
330 | * ancestor_ids[] can determine whether a given cgroup is a | |
331 | * descendant of another without traversing the hierarchy. | |
332 | */ | |
333 | int level; | |
334 | ||
1a926e0b RG |
335 | /* Maximum allowed descent tree depth */ |
336 | int max_depth; | |
337 | ||
0679dee0 RG |
338 | /* |
339 | * Keep track of total numbers of visible and dying descent cgroups. | |
340 | * Dying cgroups are cgroups which were deleted by a user, | |
341 | * but are still existing because someone else is holding a reference. | |
1a926e0b | 342 | * max_descendants is a maximum allowed number of descent cgroups. |
8d747b13 RG |
343 | * |
344 | * nr_descendants and nr_dying_descendants are protected | |
345 | * by cgroup_mutex and css_set_lock. It's fine to read them holding | |
346 | * any of cgroup_mutex and css_set_lock; for writing both locks | |
347 | * should be held. | |
0679dee0 RG |
348 | */ |
349 | int nr_descendants; | |
350 | int nr_dying_descendants; | |
1a926e0b | 351 | int max_descendants; |
0679dee0 | 352 | |
b4a04ab7 | 353 | /* |
0de0942d | 354 | * Each non-empty css_set associated with this cgroup contributes |
788b950c TH |
355 | * one to nr_populated_csets. The counter is zero iff this cgroup |
356 | * doesn't have any tasks. | |
357 | * | |
358 | * All children which have non-zero nr_populated_csets and/or | |
454000ad TH |
359 | * nr_populated_children of their own contribute one to either |
360 | * nr_populated_domain_children or nr_populated_threaded_children | |
361 | * depending on their type. Each counter is zero iff all cgroups | |
362 | * of the type in the subtree proper don't have any tasks. | |
b4a04ab7 | 363 | */ |
788b950c | 364 | int nr_populated_csets; |
454000ad TH |
365 | int nr_populated_domain_children; |
366 | int nr_populated_threaded_children; | |
367 | ||
368 | int nr_threaded_children; /* # of live threaded child cgroups */ | |
b4a04ab7 TH |
369 | |
370 | struct kernfs_node *kn; /* cgroup kernfs entry */ | |
6f60eade TH |
371 | struct cgroup_file procs_file; /* handle for "cgroup.procs" */ |
372 | struct cgroup_file events_file; /* handle for "cgroup.events" */ | |
b4a04ab7 TH |
373 | |
374 | /* | |
375 | * The bitmask of subsystems enabled on the child cgroups. | |
376 | * ->subtree_control is the one configured through | |
8699b776 TH |
377 | * "cgroup.subtree_control" while ->child_ss_mask is the effective |
378 | * one which may have more subsystems enabled. Controller knobs | |
379 | * are made available iff it's enabled in ->subtree_control. | |
b4a04ab7 | 380 | */ |
6e5c8307 TH |
381 | u16 subtree_control; |
382 | u16 subtree_ss_mask; | |
15a27c36 TH |
383 | u16 old_subtree_control; |
384 | u16 old_subtree_ss_mask; | |
b4a04ab7 TH |
385 | |
386 | /* Private pointers for each registered subsystem */ | |
387 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; | |
388 | ||
389 | struct cgroup_root *root; | |
390 | ||
391 | /* | |
392 | * List of cgrp_cset_links pointing at css_sets with tasks in this | |
393 | * cgroup. Protected by css_set_lock. | |
394 | */ | |
395 | struct list_head cset_links; | |
396 | ||
397 | /* | |
398 | * On the default hierarchy, a css_set for a cgroup with some | |
399 | * susbsys disabled will point to css's which are associated with | |
400 | * the closest ancestor which has the subsys enabled. The | |
401 | * following lists all css_sets which point to this cgroup's css | |
402 | * for the given subsystem. | |
403 | */ | |
404 | struct list_head e_csets[CGROUP_SUBSYS_COUNT]; | |
405 | ||
454000ad TH |
406 | /* |
407 | * If !threaded, self. If threaded, it points to the nearest | |
408 | * domain ancestor. Inside a threaded subtree, cgroups are exempt | |
409 | * from process granularity and no-internal-task constraint. | |
410 | * Domain level resource consumptions which aren't tied to a | |
411 | * specific task are charged to the dom_cgrp. | |
412 | */ | |
413 | struct cgroup *dom_cgrp; | |
efce8f8c | 414 | struct cgroup *old_dom_cgrp; /* used while enabling threaded */ |
454000ad | 415 | |
041cd640 TH |
416 | /* cgroup basic resource statistics */ |
417 | struct cgroup_cpu_stat __percpu *cpu_stat; | |
418 | struct cgroup_stat pending_stat; /* pending from children */ | |
419 | struct cgroup_stat stat; | |
420 | ||
b4a04ab7 TH |
421 | /* |
422 | * list of pidlists, up to two for each namespace (one for procs, one | |
423 | * for tasks); created on demand. | |
424 | */ | |
425 | struct list_head pidlists; | |
426 | struct mutex pidlist_mutex; | |
427 | ||
428 | /* used to wait for offlining of csses */ | |
429 | wait_queue_head_t offline_waitq; | |
430 | ||
431 | /* used to schedule release agent */ | |
432 | struct work_struct release_agent_work; | |
b11cfb58 | 433 | |
30070984 DM |
434 | /* used to store eBPF programs */ |
435 | struct cgroup_bpf bpf; | |
436 | ||
b11cfb58 TH |
437 | /* ids of the ancestors at each level including self */ |
438 | int ancestor_ids[]; | |
b4a04ab7 TH |
439 | }; |
440 | ||
441 | /* | |
442 | * A cgroup_root represents the root of a cgroup hierarchy, and may be | |
443 | * associated with a kernfs_root to form an active hierarchy. This is | |
444 | * internal to cgroup core. Don't access directly from controllers. | |
445 | */ | |
446 | struct cgroup_root { | |
447 | struct kernfs_root *kf_root; | |
448 | ||
449 | /* The bitmask of subsystems attached to this hierarchy */ | |
450 | unsigned int subsys_mask; | |
451 | ||
452 | /* Unique id for this hierarchy. */ | |
453 | int hierarchy_id; | |
454 | ||
455 | /* The root cgroup. Root is destroyed on its release. */ | |
456 | struct cgroup cgrp; | |
457 | ||
b11cfb58 TH |
458 | /* for cgrp->ancestor_ids[0] */ |
459 | int cgrp_ancestor_id_storage; | |
460 | ||
b4a04ab7 TH |
461 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
462 | atomic_t nr_cgrps; | |
463 | ||
464 | /* A list running through the active hierarchies */ | |
465 | struct list_head root_list; | |
466 | ||
467 | /* Hierarchy-specific flags */ | |
468 | unsigned int flags; | |
469 | ||
470 | /* IDs for cgroups in this hierarchy */ | |
471 | struct idr cgroup_idr; | |
472 | ||
473 | /* The path to use for release notifications. */ | |
474 | char release_agent_path[PATH_MAX]; | |
475 | ||
476 | /* The name for this hierarchy - may be empty */ | |
477 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
478 | }; | |
479 | ||
480 | /* | |
481 | * struct cftype: handler definitions for cgroup control files | |
482 | * | |
483 | * When reading/writing to a file: | |
484 | * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata | |
485 | * - the 'cftype' of the file is file->f_path.dentry->d_fsdata | |
486 | */ | |
487 | struct cftype { | |
488 | /* | |
489 | * By convention, the name should begin with the name of the | |
490 | * subsystem, followed by a period. Zero length string indicates | |
491 | * end of cftype array. | |
492 | */ | |
493 | char name[MAX_CFTYPE_NAME]; | |
731a981e | 494 | unsigned long private; |
b4a04ab7 TH |
495 | |
496 | /* | |
497 | * The maximum length of string, excluding trailing nul, that can | |
498 | * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. | |
499 | */ | |
500 | size_t max_write_len; | |
501 | ||
502 | /* CFTYPE_* flags */ | |
503 | unsigned int flags; | |
504 | ||
6f60eade TH |
505 | /* |
506 | * If non-zero, should contain the offset from the start of css to | |
507 | * a struct cgroup_file field. cgroup will record the handle of | |
508 | * the created file into it. The recorded handle can be used as | |
509 | * long as the containing css remains accessible. | |
510 | */ | |
511 | unsigned int file_offset; | |
512 | ||
b4a04ab7 TH |
513 | /* |
514 | * Fields used for internal bookkeeping. Initialized automatically | |
515 | * during registration. | |
516 | */ | |
517 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ | |
518 | struct list_head node; /* anchored at ss->cfts */ | |
519 | struct kernfs_ops *kf_ops; | |
520 | ||
e90cbebc TH |
521 | int (*open)(struct kernfs_open_file *of); |
522 | void (*release)(struct kernfs_open_file *of); | |
523 | ||
b4a04ab7 TH |
524 | /* |
525 | * read_u64() is a shortcut for the common case of returning a | |
526 | * single integer. Use it in place of read() | |
527 | */ | |
528 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
529 | /* | |
530 | * read_s64() is a signed version of read_u64() | |
531 | */ | |
532 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
533 | ||
534 | /* generic seq_file read interface */ | |
535 | int (*seq_show)(struct seq_file *sf, void *v); | |
536 | ||
537 | /* optional ops, implement all or none */ | |
538 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
539 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
540 | void (*seq_stop)(struct seq_file *sf, void *v); | |
541 | ||
542 | /* | |
543 | * write_u64() is a shortcut for the common case of accepting | |
544 | * a single integer (as parsed by simple_strtoull) from | |
545 | * userspace. Use in place of write(); return 0 or error. | |
546 | */ | |
547 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
548 | u64 val); | |
549 | /* | |
550 | * write_s64() is a signed version of write_u64() | |
551 | */ | |
552 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
553 | s64 val); | |
554 | ||
555 | /* | |
556 | * write() is the generic write callback which maps directly to | |
557 | * kernfs write operation and overrides all other operations. | |
558 | * Maximum write size is determined by ->max_write_len. Use | |
559 | * of_css/cft() to access the associated css and cft. | |
560 | */ | |
561 | ssize_t (*write)(struct kernfs_open_file *of, | |
562 | char *buf, size_t nbytes, loff_t off); | |
563 | ||
564 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
565 | struct lock_class_key lockdep_key; | |
566 | #endif | |
567 | }; | |
568 | ||
569 | /* | |
570 | * Control Group subsystem type. | |
571 | * See Documentation/cgroups/cgroups.txt for details | |
572 | */ | |
573 | struct cgroup_subsys { | |
574 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); | |
575 | int (*css_online)(struct cgroup_subsys_state *css); | |
576 | void (*css_offline)(struct cgroup_subsys_state *css); | |
577 | void (*css_released)(struct cgroup_subsys_state *css); | |
578 | void (*css_free)(struct cgroup_subsys_state *css); | |
579 | void (*css_reset)(struct cgroup_subsys_state *css); | |
d41bf8c9 TH |
580 | int (*css_extra_stat_show)(struct seq_file *seq, |
581 | struct cgroup_subsys_state *css); | |
b4a04ab7 | 582 | |
1f7dd3e5 TH |
583 | int (*can_attach)(struct cgroup_taskset *tset); |
584 | void (*cancel_attach)(struct cgroup_taskset *tset); | |
585 | void (*attach)(struct cgroup_taskset *tset); | |
5cf1cacb | 586 | void (*post_attach)(void); |
b53202e6 ON |
587 | int (*can_fork)(struct task_struct *task); |
588 | void (*cancel_fork)(struct task_struct *task); | |
589 | void (*fork)(struct task_struct *task); | |
2e91fa7f | 590 | void (*exit)(struct task_struct *task); |
d7248a93 | 591 | void (*release)(struct task_struct *task); |
b4a04ab7 TH |
592 | void (*bind)(struct cgroup_subsys_state *root_css); |
593 | ||
b38e42e9 | 594 | bool early_init:1; |
b4a04ab7 | 595 | |
f6d635ad TH |
596 | /* |
597 | * If %true, the controller, on the default hierarchy, doesn't show | |
598 | * up in "cgroup.controllers" or "cgroup.subtree_control", is | |
599 | * implicitly enabled on all cgroups on the default hierarchy, and | |
600 | * bypasses the "no internal process" constraint. This is for | |
601 | * utility type controllers which is transparent to userland. | |
602 | * | |
603 | * An implicit controller can be stolen from the default hierarchy | |
604 | * anytime and thus must be okay with offline csses from previous | |
605 | * hierarchies coexisting with csses for the current one. | |
606 | */ | |
607 | bool implicit_on_dfl:1; | |
608 | ||
8cfd8147 TH |
609 | /* |
610 | * If %true, the controller, supports threaded mode on the default | |
611 | * hierarchy. In a threaded subtree, both process granularity and | |
612 | * no-internal-process constraint are ignored and a threaded | |
613 | * controllers should be able to handle that. | |
614 | * | |
615 | * Note that as an implicit controller is automatically enabled on | |
616 | * all cgroups on the default hierarchy, it should also be | |
617 | * threaded. implicit && !threaded is not supported. | |
618 | */ | |
619 | bool threaded:1; | |
620 | ||
b4a04ab7 TH |
621 | /* |
622 | * If %false, this subsystem is properly hierarchical - | |
623 | * configuration, resource accounting and restriction on a parent | |
624 | * cgroup cover those of its children. If %true, hierarchy support | |
625 | * is broken in some ways - some subsystems ignore hierarchy | |
626 | * completely while others are only implemented half-way. | |
627 | * | |
628 | * It's now disallowed to create nested cgroups if the subsystem is | |
629 | * broken and cgroup core will emit a warning message on such | |
630 | * cases. Eventually, all subsystems will be made properly | |
631 | * hierarchical and this will go away. | |
632 | */ | |
b38e42e9 TH |
633 | bool broken_hierarchy:1; |
634 | bool warned_broken_hierarchy:1; | |
b4a04ab7 TH |
635 | |
636 | /* the following two fields are initialized automtically during boot */ | |
637 | int id; | |
638 | const char *name; | |
639 | ||
3e1d2eed TH |
640 | /* optional, initialized automatically during boot if not set */ |
641 | const char *legacy_name; | |
642 | ||
b4a04ab7 TH |
643 | /* link to parent, protected by cgroup_lock() */ |
644 | struct cgroup_root *root; | |
645 | ||
646 | /* idr for css->id */ | |
647 | struct idr css_idr; | |
648 | ||
649 | /* | |
650 | * List of cftypes. Each entry is the first entry of an array | |
651 | * terminated by zero length name. | |
652 | */ | |
653 | struct list_head cfts; | |
654 | ||
655 | /* | |
656 | * Base cftypes which are automatically registered. The two can | |
657 | * point to the same array. | |
658 | */ | |
659 | struct cftype *dfl_cftypes; /* for the default hierarchy */ | |
660 | struct cftype *legacy_cftypes; /* for the legacy hierarchies */ | |
661 | ||
662 | /* | |
663 | * A subsystem may depend on other subsystems. When such subsystem | |
664 | * is enabled on a cgroup, the depended-upon subsystems are enabled | |
665 | * together if available. Subsystems enabled due to dependency are | |
666 | * not visible to userland until explicitly enabled. The following | |
667 | * specifies the mask of subsystems that this one depends on. | |
668 | */ | |
669 | unsigned int depends_on; | |
670 | }; | |
671 | ||
1ed13287 TH |
672 | extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; |
673 | ||
674 | /** | |
675 | * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups | |
676 | * @tsk: target task | |
677 | * | |
780de9dd IM |
678 | * Allows cgroup operations to synchronize against threadgroup changes |
679 | * using a percpu_rw_semaphore. | |
1ed13287 TH |
680 | */ |
681 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) | |
682 | { | |
683 | percpu_down_read(&cgroup_threadgroup_rwsem); | |
684 | } | |
685 | ||
686 | /** | |
687 | * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups | |
688 | * @tsk: target task | |
689 | * | |
780de9dd | 690 | * Counterpart of cgroup_threadcgroup_change_begin(). |
1ed13287 TH |
691 | */ |
692 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) | |
693 | { | |
694 | percpu_up_read(&cgroup_threadgroup_rwsem); | |
695 | } | |
7d7efec3 TH |
696 | |
697 | #else /* CONFIG_CGROUPS */ | |
698 | ||
cb4a3167 AS |
699 | #define CGROUP_SUBSYS_COUNT 0 |
700 | ||
780de9dd IM |
701 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) |
702 | { | |
703 | might_sleep(); | |
704 | } | |
705 | ||
7d7efec3 TH |
706 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} |
707 | ||
b4a04ab7 | 708 | #endif /* CONFIG_CGROUPS */ |
7d7efec3 | 709 | |
2a56a1fe TH |
710 | #ifdef CONFIG_SOCK_CGROUP_DATA |
711 | ||
bd1060a1 TH |
712 | /* |
713 | * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains | |
714 | * per-socket cgroup information except for memcg association. | |
715 | * | |
716 | * On legacy hierarchies, net_prio and net_cls controllers directly set | |
717 | * attributes on each sock which can then be tested by the network layer. | |
718 | * On the default hierarchy, each sock is associated with the cgroup it was | |
719 | * created in and the networking layer can match the cgroup directly. | |
720 | * | |
721 | * To avoid carrying all three cgroup related fields separately in sock, | |
722 | * sock_cgroup_data overloads (prioidx, classid) and the cgroup pointer. | |
723 | * On boot, sock_cgroup_data records the cgroup that the sock was created | |
724 | * in so that cgroup2 matches can be made; however, once either net_prio or | |
725 | * net_cls starts being used, the area is overriden to carry prioidx and/or | |
726 | * classid. The two modes are distinguished by whether the lowest bit is | |
727 | * set. Clear bit indicates cgroup pointer while set bit prioidx and | |
728 | * classid. | |
729 | * | |
730 | * While userland may start using net_prio or net_cls at any time, once | |
731 | * either is used, cgroup2 matching no longer works. There is no reason to | |
732 | * mix the two and this is in line with how legacy and v2 compatibility is | |
733 | * handled. On mode switch, cgroup references which are already being | |
734 | * pointed to by socks may be leaked. While this can be remedied by adding | |
735 | * synchronization around sock_cgroup_data, given that the number of leaked | |
736 | * cgroups is bound and highly unlikely to be high, this seems to be the | |
737 | * better trade-off. | |
738 | */ | |
2a56a1fe | 739 | struct sock_cgroup_data { |
bd1060a1 TH |
740 | union { |
741 | #ifdef __LITTLE_ENDIAN | |
742 | struct { | |
743 | u8 is_data; | |
744 | u8 padding; | |
745 | u16 prioidx; | |
746 | u32 classid; | |
747 | } __packed; | |
748 | #else | |
749 | struct { | |
750 | u32 classid; | |
751 | u16 prioidx; | |
752 | u8 padding; | |
753 | u8 is_data; | |
754 | } __packed; | |
755 | #endif | |
756 | u64 val; | |
757 | }; | |
2a56a1fe TH |
758 | }; |
759 | ||
bd1060a1 TH |
760 | /* |
761 | * There's a theoretical window where the following accessors race with | |
762 | * updaters and return part of the previous pointer as the prioidx or | |
763 | * classid. Such races are short-lived and the result isn't critical. | |
764 | */ | |
699cb7c6 | 765 | static inline u16 sock_cgroup_prioidx(const struct sock_cgroup_data *skcd) |
2a56a1fe | 766 | { |
bd1060a1 TH |
767 | /* fallback to 1 which is always the ID of the root cgroup */ |
768 | return (skcd->is_data & 1) ? skcd->prioidx : 1; | |
2a56a1fe TH |
769 | } |
770 | ||
699cb7c6 | 771 | static inline u32 sock_cgroup_classid(const struct sock_cgroup_data *skcd) |
2a56a1fe | 772 | { |
bd1060a1 TH |
773 | /* fallback to 0 which is the unconfigured default classid */ |
774 | return (skcd->is_data & 1) ? skcd->classid : 0; | |
2a56a1fe TH |
775 | } |
776 | ||
bd1060a1 TH |
777 | /* |
778 | * If invoked concurrently, the updaters may clobber each other. The | |
779 | * caller is responsible for synchronization. | |
780 | */ | |
2a56a1fe TH |
781 | static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, |
782 | u16 prioidx) | |
783 | { | |
ad2c8c73 | 784 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
785 | |
786 | if (sock_cgroup_prioidx(&skcd_buf) == prioidx) | |
787 | return; | |
788 | ||
789 | if (!(skcd_buf.is_data & 1)) { | |
790 | skcd_buf.val = 0; | |
791 | skcd_buf.is_data = 1; | |
792 | } | |
793 | ||
794 | skcd_buf.prioidx = prioidx; | |
795 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
796 | } |
797 | ||
798 | static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, | |
799 | u32 classid) | |
800 | { | |
ad2c8c73 | 801 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
802 | |
803 | if (sock_cgroup_classid(&skcd_buf) == classid) | |
804 | return; | |
805 | ||
806 | if (!(skcd_buf.is_data & 1)) { | |
807 | skcd_buf.val = 0; | |
808 | skcd_buf.is_data = 1; | |
809 | } | |
810 | ||
811 | skcd_buf.classid = classid; | |
812 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
813 | } |
814 | ||
815 | #else /* CONFIG_SOCK_CGROUP_DATA */ | |
816 | ||
817 | struct sock_cgroup_data { | |
818 | }; | |
819 | ||
820 | #endif /* CONFIG_SOCK_CGROUP_DATA */ | |
821 | ||
b4a04ab7 | 822 | #endif /* _LINUX_CGROUP_DEFS_H */ |