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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> |
b4a04ab7 | 20 | #include <linux/workqueue.h> |
30070984 | 21 | #include <linux/bpf-cgroup.h> |
b4a04ab7 TH |
22 | |
23 | #ifdef CONFIG_CGROUPS | |
24 | ||
25 | struct cgroup; | |
26 | struct cgroup_root; | |
27 | struct cgroup_subsys; | |
28 | struct cgroup_taskset; | |
29 | struct kernfs_node; | |
30 | struct kernfs_ops; | |
31 | struct kernfs_open_file; | |
c80ef9e0 | 32 | struct seq_file; |
b4a04ab7 TH |
33 | |
34 | #define MAX_CGROUP_TYPE_NAMELEN 32 | |
35 | #define MAX_CGROUP_ROOT_NAMELEN 64 | |
36 | #define MAX_CFTYPE_NAME 64 | |
37 | ||
38 | /* define the enumeration of all cgroup subsystems */ | |
39 | #define SUBSYS(_x) _x ## _cgrp_id, | |
40 | enum cgroup_subsys_id { | |
41 | #include <linux/cgroup_subsys.h> | |
42 | CGROUP_SUBSYS_COUNT, | |
43 | }; | |
44 | #undef SUBSYS | |
45 | ||
46 | /* bits in struct cgroup_subsys_state flags field */ | |
47 | enum { | |
48 | CSS_NO_REF = (1 << 0), /* no reference counting for this css */ | |
49 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ | |
50 | CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ | |
88cb04b9 | 51 | CSS_VISIBLE = (1 << 3), /* css is visible to userland */ |
33c35aa4 | 52 | CSS_DYING = (1 << 4), /* css is dying */ |
b4a04ab7 TH |
53 | }; |
54 | ||
55 | /* bits in struct cgroup flags field */ | |
56 | enum { | |
57 | /* Control Group requires release notifications to userspace */ | |
58 | CGRP_NOTIFY_ON_RELEASE, | |
59 | /* | |
60 | * Clone the parent's configuration when creating a new child | |
61 | * cpuset cgroup. For historical reasons, this option can be | |
62 | * specified at mount time and thus is implemented here. | |
63 | */ | |
64 | CGRP_CPUSET_CLONE_CHILDREN, | |
65 | }; | |
66 | ||
67 | /* cgroup_root->flags */ | |
68 | enum { | |
b4a04ab7 TH |
69 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
70 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
5136f636 TH |
71 | |
72 | /* | |
73 | * Consider namespaces as delegation boundaries. If this flag is | |
74 | * set, controller specific interface files in a namespace root | |
75 | * aren't writeable from inside the namespace. | |
76 | */ | |
77 | CGRP_ROOT_NS_DELEGATE = (1 << 3), | |
e1cba4b8 WL |
78 | |
79 | /* | |
80 | * Enable cpuset controller in v1 cgroup to use v2 behavior. | |
81 | */ | |
82 | CGRP_ROOT_CPUSET_V2_MODE = (1 << 4), | |
b4a04ab7 TH |
83 | }; |
84 | ||
85 | /* cftype->flags */ | |
86 | enum { | |
87 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ | |
88 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
5136f636 TH |
89 | CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */ |
90 | ||
b4a04ab7 | 91 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
7dbdb199 | 92 | CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ |
b4a04ab7 TH |
93 | |
94 | /* internal flags, do not use outside cgroup core proper */ | |
95 | __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ | |
96 | __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ | |
97 | }; | |
98 | ||
6f60eade TH |
99 | /* |
100 | * cgroup_file is the handle for a file instance created in a cgroup which | |
101 | * is used, for example, to generate file changed notifications. This can | |
102 | * be obtained by setting cftype->file_offset. | |
103 | */ | |
104 | struct cgroup_file { | |
105 | /* do not access any fields from outside cgroup core */ | |
6f60eade TH |
106 | struct kernfs_node *kn; |
107 | }; | |
108 | ||
b4a04ab7 TH |
109 | /* |
110 | * Per-subsystem/per-cgroup state maintained by the system. This is the | |
111 | * fundamental structural building block that controllers deal with. | |
112 | * | |
113 | * Fields marked with "PI:" are public and immutable and may be accessed | |
114 | * directly without synchronization. | |
115 | */ | |
116 | struct cgroup_subsys_state { | |
117 | /* PI: the cgroup that this css is attached to */ | |
118 | struct cgroup *cgroup; | |
119 | ||
120 | /* PI: the cgroup subsystem that this css is attached to */ | |
121 | struct cgroup_subsys *ss; | |
122 | ||
123 | /* reference count - access via css_[try]get() and css_put() */ | |
124 | struct percpu_ref refcnt; | |
125 | ||
b4a04ab7 TH |
126 | /* siblings list anchored at the parent's ->children */ |
127 | struct list_head sibling; | |
128 | struct list_head children; | |
129 | ||
130 | /* | |
131 | * PI: Subsys-unique ID. 0 is unused and root is always 1. The | |
132 | * matching css can be looked up using css_from_id(). | |
133 | */ | |
134 | int id; | |
135 | ||
136 | unsigned int flags; | |
137 | ||
138 | /* | |
139 | * Monotonically increasing unique serial number which defines a | |
140 | * uniform order among all csses. It's guaranteed that all | |
141 | * ->children lists are in the ascending order of ->serial_nr and | |
142 | * used to allow interrupting and resuming iterations. | |
143 | */ | |
144 | u64 serial_nr; | |
145 | ||
aa226ff4 TH |
146 | /* |
147 | * Incremented by online self and children. Used to guarantee that | |
148 | * parents are not offlined before their children. | |
149 | */ | |
150 | atomic_t online_cnt; | |
151 | ||
b4a04ab7 TH |
152 | /* percpu_ref killing and RCU release */ |
153 | struct rcu_head rcu_head; | |
154 | struct work_struct destroy_work; | |
b8b1a2e5 TP |
155 | |
156 | /* | |
157 | * PI: the parent css. Placed here for cache proximity to following | |
158 | * fields of the containing structure. | |
159 | */ | |
160 | struct cgroup_subsys_state *parent; | |
b4a04ab7 TH |
161 | }; |
162 | ||
163 | /* | |
164 | * A css_set is a structure holding pointers to a set of | |
165 | * cgroup_subsys_state objects. This saves space in the task struct | |
166 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
167 | * list_add()/del() can bump the reference count on the entire cgroup | |
168 | * set for a task. | |
169 | */ | |
170 | struct css_set { | |
b4a04ab7 | 171 | /* |
5f617ebb TH |
172 | * Set of subsystem states, one for each subsystem. This array is |
173 | * immutable after creation apart from the init_css_set during | |
174 | * subsystem registration (at boot time). | |
b4a04ab7 | 175 | */ |
5f617ebb TH |
176 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
177 | ||
178 | /* reference count */ | |
4b9502e6 | 179 | refcount_t refcount; |
5f617ebb | 180 | |
454000ad TH |
181 | /* |
182 | * For a domain cgroup, the following points to self. If threaded, | |
183 | * to the matching cset of the nearest domain ancestor. The | |
184 | * dom_cset provides access to the domain cgroup and its csses to | |
185 | * which domain level resource consumptions should be charged. | |
186 | */ | |
187 | struct css_set *dom_cset; | |
188 | ||
5f617ebb TH |
189 | /* the default cgroup associated with this css_set */ |
190 | struct cgroup *dfl_cgrp; | |
b4a04ab7 | 191 | |
73a7242a WL |
192 | /* internal task count, protected by css_set_lock */ |
193 | int nr_tasks; | |
194 | ||
b4a04ab7 TH |
195 | /* |
196 | * Lists running through all tasks using this cgroup group. | |
197 | * mg_tasks lists tasks which belong to this cset but are in the | |
198 | * process of being migrated out or in. Protected by | |
199 | * css_set_rwsem, but, during migration, once tasks are moved to | |
200 | * mg_tasks, it can be read safely while holding cgroup_mutex. | |
201 | */ | |
202 | struct list_head tasks; | |
203 | struct list_head mg_tasks; | |
204 | ||
5f617ebb TH |
205 | /* all css_task_iters currently walking this cset */ |
206 | struct list_head task_iters; | |
207 | ||
b4a04ab7 | 208 | /* |
5f617ebb TH |
209 | * On the default hierarhcy, ->subsys[ssid] may point to a css |
210 | * attached to an ancestor instead of the cgroup this css_set is | |
211 | * associated with. The following node is anchored at | |
212 | * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to | |
213 | * iterate through all css's attached to a given cgroup. | |
b4a04ab7 | 214 | */ |
5f617ebb | 215 | struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; |
b4a04ab7 | 216 | |
454000ad TH |
217 | /* all threaded csets whose ->dom_cset points to this cset */ |
218 | struct list_head threaded_csets; | |
219 | struct list_head threaded_csets_node; | |
220 | ||
5f617ebb TH |
221 | /* |
222 | * List running through all cgroup groups in the same hash | |
223 | * slot. Protected by css_set_lock | |
224 | */ | |
225 | struct hlist_node hlist; | |
b4a04ab7 TH |
226 | |
227 | /* | |
5f617ebb TH |
228 | * List of cgrp_cset_links pointing at cgroups referenced from this |
229 | * css_set. Protected by css_set_lock. | |
b4a04ab7 | 230 | */ |
5f617ebb | 231 | struct list_head cgrp_links; |
b4a04ab7 TH |
232 | |
233 | /* | |
234 | * List of csets participating in the on-going migration either as | |
235 | * source or destination. Protected by cgroup_mutex. | |
236 | */ | |
237 | struct list_head mg_preload_node; | |
238 | struct list_head mg_node; | |
239 | ||
240 | /* | |
241 | * If this cset is acting as the source of migration the following | |
e4857982 TH |
242 | * two fields are set. mg_src_cgrp and mg_dst_cgrp are |
243 | * respectively the source and destination cgroups of the on-going | |
244 | * migration. mg_dst_cset is the destination cset the target tasks | |
245 | * on this cset should be migrated to. Protected by cgroup_mutex. | |
b4a04ab7 TH |
246 | */ |
247 | struct cgroup *mg_src_cgrp; | |
e4857982 | 248 | struct cgroup *mg_dst_cgrp; |
b4a04ab7 TH |
249 | struct css_set *mg_dst_cset; |
250 | ||
2b021cbf TH |
251 | /* dead and being drained, ignore for migration */ |
252 | bool dead; | |
253 | ||
b4a04ab7 TH |
254 | /* For RCU-protected deletion */ |
255 | struct rcu_head rcu_head; | |
256 | }; | |
257 | ||
258 | struct cgroup { | |
259 | /* self css with NULL ->ss, points back to this cgroup */ | |
260 | struct cgroup_subsys_state self; | |
261 | ||
262 | unsigned long flags; /* "unsigned long" so bitops work */ | |
263 | ||
264 | /* | |
265 | * idr allocated in-hierarchy ID. | |
266 | * | |
267 | * ID 0 is not used, the ID of the root cgroup is always 1, and a | |
268 | * new cgroup will be assigned with a smallest available ID. | |
269 | * | |
270 | * Allocating/Removing ID must be protected by cgroup_mutex. | |
271 | */ | |
272 | int id; | |
273 | ||
b11cfb58 TH |
274 | /* |
275 | * The depth this cgroup is at. The root is at depth zero and each | |
276 | * step down the hierarchy increments the level. This along with | |
277 | * ancestor_ids[] can determine whether a given cgroup is a | |
278 | * descendant of another without traversing the hierarchy. | |
279 | */ | |
280 | int level; | |
281 | ||
1a926e0b RG |
282 | /* Maximum allowed descent tree depth */ |
283 | int max_depth; | |
284 | ||
0679dee0 RG |
285 | /* |
286 | * Keep track of total numbers of visible and dying descent cgroups. | |
287 | * Dying cgroups are cgroups which were deleted by a user, | |
288 | * but are still existing because someone else is holding a reference. | |
1a926e0b | 289 | * max_descendants is a maximum allowed number of descent cgroups. |
0679dee0 RG |
290 | */ |
291 | int nr_descendants; | |
292 | int nr_dying_descendants; | |
1a926e0b | 293 | int max_descendants; |
0679dee0 | 294 | |
b4a04ab7 | 295 | /* |
0de0942d | 296 | * Each non-empty css_set associated with this cgroup contributes |
788b950c TH |
297 | * one to nr_populated_csets. The counter is zero iff this cgroup |
298 | * doesn't have any tasks. | |
299 | * | |
300 | * All children which have non-zero nr_populated_csets and/or | |
454000ad TH |
301 | * nr_populated_children of their own contribute one to either |
302 | * nr_populated_domain_children or nr_populated_threaded_children | |
303 | * depending on their type. Each counter is zero iff all cgroups | |
304 | * of the type in the subtree proper don't have any tasks. | |
b4a04ab7 | 305 | */ |
788b950c | 306 | int nr_populated_csets; |
454000ad TH |
307 | int nr_populated_domain_children; |
308 | int nr_populated_threaded_children; | |
309 | ||
310 | int nr_threaded_children; /* # of live threaded child cgroups */ | |
b4a04ab7 TH |
311 | |
312 | struct kernfs_node *kn; /* cgroup kernfs entry */ | |
6f60eade TH |
313 | struct cgroup_file procs_file; /* handle for "cgroup.procs" */ |
314 | struct cgroup_file events_file; /* handle for "cgroup.events" */ | |
b4a04ab7 TH |
315 | |
316 | /* | |
317 | * The bitmask of subsystems enabled on the child cgroups. | |
318 | * ->subtree_control is the one configured through | |
8699b776 TH |
319 | * "cgroup.subtree_control" while ->child_ss_mask is the effective |
320 | * one which may have more subsystems enabled. Controller knobs | |
321 | * are made available iff it's enabled in ->subtree_control. | |
b4a04ab7 | 322 | */ |
6e5c8307 TH |
323 | u16 subtree_control; |
324 | u16 subtree_ss_mask; | |
15a27c36 TH |
325 | u16 old_subtree_control; |
326 | u16 old_subtree_ss_mask; | |
b4a04ab7 TH |
327 | |
328 | /* Private pointers for each registered subsystem */ | |
329 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; | |
330 | ||
331 | struct cgroup_root *root; | |
332 | ||
333 | /* | |
334 | * List of cgrp_cset_links pointing at css_sets with tasks in this | |
335 | * cgroup. Protected by css_set_lock. | |
336 | */ | |
337 | struct list_head cset_links; | |
338 | ||
339 | /* | |
340 | * On the default hierarchy, a css_set for a cgroup with some | |
341 | * susbsys disabled will point to css's which are associated with | |
342 | * the closest ancestor which has the subsys enabled. The | |
343 | * following lists all css_sets which point to this cgroup's css | |
344 | * for the given subsystem. | |
345 | */ | |
346 | struct list_head e_csets[CGROUP_SUBSYS_COUNT]; | |
347 | ||
454000ad TH |
348 | /* |
349 | * If !threaded, self. If threaded, it points to the nearest | |
350 | * domain ancestor. Inside a threaded subtree, cgroups are exempt | |
351 | * from process granularity and no-internal-task constraint. | |
352 | * Domain level resource consumptions which aren't tied to a | |
353 | * specific task are charged to the dom_cgrp. | |
354 | */ | |
355 | struct cgroup *dom_cgrp; | |
356 | ||
b4a04ab7 TH |
357 | /* |
358 | * list of pidlists, up to two for each namespace (one for procs, one | |
359 | * for tasks); created on demand. | |
360 | */ | |
361 | struct list_head pidlists; | |
362 | struct mutex pidlist_mutex; | |
363 | ||
364 | /* used to wait for offlining of csses */ | |
365 | wait_queue_head_t offline_waitq; | |
366 | ||
367 | /* used to schedule release agent */ | |
368 | struct work_struct release_agent_work; | |
b11cfb58 | 369 | |
30070984 DM |
370 | /* used to store eBPF programs */ |
371 | struct cgroup_bpf bpf; | |
372 | ||
b11cfb58 TH |
373 | /* ids of the ancestors at each level including self */ |
374 | int ancestor_ids[]; | |
b4a04ab7 TH |
375 | }; |
376 | ||
377 | /* | |
378 | * A cgroup_root represents the root of a cgroup hierarchy, and may be | |
379 | * associated with a kernfs_root to form an active hierarchy. This is | |
380 | * internal to cgroup core. Don't access directly from controllers. | |
381 | */ | |
382 | struct cgroup_root { | |
383 | struct kernfs_root *kf_root; | |
384 | ||
385 | /* The bitmask of subsystems attached to this hierarchy */ | |
386 | unsigned int subsys_mask; | |
387 | ||
388 | /* Unique id for this hierarchy. */ | |
389 | int hierarchy_id; | |
390 | ||
391 | /* The root cgroup. Root is destroyed on its release. */ | |
392 | struct cgroup cgrp; | |
393 | ||
b11cfb58 TH |
394 | /* for cgrp->ancestor_ids[0] */ |
395 | int cgrp_ancestor_id_storage; | |
396 | ||
b4a04ab7 TH |
397 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
398 | atomic_t nr_cgrps; | |
399 | ||
400 | /* A list running through the active hierarchies */ | |
401 | struct list_head root_list; | |
402 | ||
403 | /* Hierarchy-specific flags */ | |
404 | unsigned int flags; | |
405 | ||
406 | /* IDs for cgroups in this hierarchy */ | |
407 | struct idr cgroup_idr; | |
408 | ||
409 | /* The path to use for release notifications. */ | |
410 | char release_agent_path[PATH_MAX]; | |
411 | ||
412 | /* The name for this hierarchy - may be empty */ | |
413 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
414 | }; | |
415 | ||
416 | /* | |
417 | * struct cftype: handler definitions for cgroup control files | |
418 | * | |
419 | * When reading/writing to a file: | |
420 | * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata | |
421 | * - the 'cftype' of the file is file->f_path.dentry->d_fsdata | |
422 | */ | |
423 | struct cftype { | |
424 | /* | |
425 | * By convention, the name should begin with the name of the | |
426 | * subsystem, followed by a period. Zero length string indicates | |
427 | * end of cftype array. | |
428 | */ | |
429 | char name[MAX_CFTYPE_NAME]; | |
731a981e | 430 | unsigned long private; |
b4a04ab7 TH |
431 | |
432 | /* | |
433 | * The maximum length of string, excluding trailing nul, that can | |
434 | * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. | |
435 | */ | |
436 | size_t max_write_len; | |
437 | ||
438 | /* CFTYPE_* flags */ | |
439 | unsigned int flags; | |
440 | ||
6f60eade TH |
441 | /* |
442 | * If non-zero, should contain the offset from the start of css to | |
443 | * a struct cgroup_file field. cgroup will record the handle of | |
444 | * the created file into it. The recorded handle can be used as | |
445 | * long as the containing css remains accessible. | |
446 | */ | |
447 | unsigned int file_offset; | |
448 | ||
b4a04ab7 TH |
449 | /* |
450 | * Fields used for internal bookkeeping. Initialized automatically | |
451 | * during registration. | |
452 | */ | |
453 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ | |
454 | struct list_head node; /* anchored at ss->cfts */ | |
455 | struct kernfs_ops *kf_ops; | |
456 | ||
e90cbebc TH |
457 | int (*open)(struct kernfs_open_file *of); |
458 | void (*release)(struct kernfs_open_file *of); | |
459 | ||
b4a04ab7 TH |
460 | /* |
461 | * read_u64() is a shortcut for the common case of returning a | |
462 | * single integer. Use it in place of read() | |
463 | */ | |
464 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
465 | /* | |
466 | * read_s64() is a signed version of read_u64() | |
467 | */ | |
468 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
469 | ||
470 | /* generic seq_file read interface */ | |
471 | int (*seq_show)(struct seq_file *sf, void *v); | |
472 | ||
473 | /* optional ops, implement all or none */ | |
474 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
475 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
476 | void (*seq_stop)(struct seq_file *sf, void *v); | |
477 | ||
478 | /* | |
479 | * write_u64() is a shortcut for the common case of accepting | |
480 | * a single integer (as parsed by simple_strtoull) from | |
481 | * userspace. Use in place of write(); return 0 or error. | |
482 | */ | |
483 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
484 | u64 val); | |
485 | /* | |
486 | * write_s64() is a signed version of write_u64() | |
487 | */ | |
488 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
489 | s64 val); | |
490 | ||
491 | /* | |
492 | * write() is the generic write callback which maps directly to | |
493 | * kernfs write operation and overrides all other operations. | |
494 | * Maximum write size is determined by ->max_write_len. Use | |
495 | * of_css/cft() to access the associated css and cft. | |
496 | */ | |
497 | ssize_t (*write)(struct kernfs_open_file *of, | |
498 | char *buf, size_t nbytes, loff_t off); | |
499 | ||
500 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
501 | struct lock_class_key lockdep_key; | |
502 | #endif | |
503 | }; | |
504 | ||
505 | /* | |
506 | * Control Group subsystem type. | |
507 | * See Documentation/cgroups/cgroups.txt for details | |
508 | */ | |
509 | struct cgroup_subsys { | |
510 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); | |
511 | int (*css_online)(struct cgroup_subsys_state *css); | |
512 | void (*css_offline)(struct cgroup_subsys_state *css); | |
513 | void (*css_released)(struct cgroup_subsys_state *css); | |
514 | void (*css_free)(struct cgroup_subsys_state *css); | |
515 | void (*css_reset)(struct cgroup_subsys_state *css); | |
b4a04ab7 | 516 | |
1f7dd3e5 TH |
517 | int (*can_attach)(struct cgroup_taskset *tset); |
518 | void (*cancel_attach)(struct cgroup_taskset *tset); | |
519 | void (*attach)(struct cgroup_taskset *tset); | |
5cf1cacb | 520 | void (*post_attach)(void); |
b53202e6 ON |
521 | int (*can_fork)(struct task_struct *task); |
522 | void (*cancel_fork)(struct task_struct *task); | |
523 | void (*fork)(struct task_struct *task); | |
2e91fa7f | 524 | void (*exit)(struct task_struct *task); |
afcf6c8b | 525 | void (*free)(struct task_struct *task); |
b4a04ab7 TH |
526 | void (*bind)(struct cgroup_subsys_state *root_css); |
527 | ||
b38e42e9 | 528 | bool early_init:1; |
b4a04ab7 | 529 | |
f6d635ad TH |
530 | /* |
531 | * If %true, the controller, on the default hierarchy, doesn't show | |
532 | * up in "cgroup.controllers" or "cgroup.subtree_control", is | |
533 | * implicitly enabled on all cgroups on the default hierarchy, and | |
534 | * bypasses the "no internal process" constraint. This is for | |
535 | * utility type controllers which is transparent to userland. | |
536 | * | |
537 | * An implicit controller can be stolen from the default hierarchy | |
538 | * anytime and thus must be okay with offline csses from previous | |
539 | * hierarchies coexisting with csses for the current one. | |
540 | */ | |
541 | bool implicit_on_dfl:1; | |
542 | ||
8cfd8147 TH |
543 | /* |
544 | * If %true, the controller, supports threaded mode on the default | |
545 | * hierarchy. In a threaded subtree, both process granularity and | |
546 | * no-internal-process constraint are ignored and a threaded | |
547 | * controllers should be able to handle that. | |
548 | * | |
549 | * Note that as an implicit controller is automatically enabled on | |
550 | * all cgroups on the default hierarchy, it should also be | |
551 | * threaded. implicit && !threaded is not supported. | |
552 | */ | |
553 | bool threaded:1; | |
554 | ||
b4a04ab7 TH |
555 | /* |
556 | * If %false, this subsystem is properly hierarchical - | |
557 | * configuration, resource accounting and restriction on a parent | |
558 | * cgroup cover those of its children. If %true, hierarchy support | |
559 | * is broken in some ways - some subsystems ignore hierarchy | |
560 | * completely while others are only implemented half-way. | |
561 | * | |
562 | * It's now disallowed to create nested cgroups if the subsystem is | |
563 | * broken and cgroup core will emit a warning message on such | |
564 | * cases. Eventually, all subsystems will be made properly | |
565 | * hierarchical and this will go away. | |
566 | */ | |
b38e42e9 TH |
567 | bool broken_hierarchy:1; |
568 | bool warned_broken_hierarchy:1; | |
b4a04ab7 TH |
569 | |
570 | /* the following two fields are initialized automtically during boot */ | |
571 | int id; | |
572 | const char *name; | |
573 | ||
3e1d2eed TH |
574 | /* optional, initialized automatically during boot if not set */ |
575 | const char *legacy_name; | |
576 | ||
b4a04ab7 TH |
577 | /* link to parent, protected by cgroup_lock() */ |
578 | struct cgroup_root *root; | |
579 | ||
580 | /* idr for css->id */ | |
581 | struct idr css_idr; | |
582 | ||
583 | /* | |
584 | * List of cftypes. Each entry is the first entry of an array | |
585 | * terminated by zero length name. | |
586 | */ | |
587 | struct list_head cfts; | |
588 | ||
589 | /* | |
590 | * Base cftypes which are automatically registered. The two can | |
591 | * point to the same array. | |
592 | */ | |
593 | struct cftype *dfl_cftypes; /* for the default hierarchy */ | |
594 | struct cftype *legacy_cftypes; /* for the legacy hierarchies */ | |
595 | ||
596 | /* | |
597 | * A subsystem may depend on other subsystems. When such subsystem | |
598 | * is enabled on a cgroup, the depended-upon subsystems are enabled | |
599 | * together if available. Subsystems enabled due to dependency are | |
600 | * not visible to userland until explicitly enabled. The following | |
601 | * specifies the mask of subsystems that this one depends on. | |
602 | */ | |
603 | unsigned int depends_on; | |
604 | }; | |
605 | ||
1ed13287 TH |
606 | extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; |
607 | ||
608 | /** | |
609 | * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups | |
610 | * @tsk: target task | |
611 | * | |
780de9dd IM |
612 | * Allows cgroup operations to synchronize against threadgroup changes |
613 | * using a percpu_rw_semaphore. | |
1ed13287 TH |
614 | */ |
615 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) | |
616 | { | |
617 | percpu_down_read(&cgroup_threadgroup_rwsem); | |
618 | } | |
619 | ||
620 | /** | |
621 | * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups | |
622 | * @tsk: target task | |
623 | * | |
780de9dd | 624 | * Counterpart of cgroup_threadcgroup_change_begin(). |
1ed13287 TH |
625 | */ |
626 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) | |
627 | { | |
628 | percpu_up_read(&cgroup_threadgroup_rwsem); | |
629 | } | |
7d7efec3 TH |
630 | |
631 | #else /* CONFIG_CGROUPS */ | |
632 | ||
cb4a3167 AS |
633 | #define CGROUP_SUBSYS_COUNT 0 |
634 | ||
780de9dd IM |
635 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) |
636 | { | |
637 | might_sleep(); | |
638 | } | |
639 | ||
7d7efec3 TH |
640 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} |
641 | ||
b4a04ab7 | 642 | #endif /* CONFIG_CGROUPS */ |
7d7efec3 | 643 | |
2a56a1fe TH |
644 | #ifdef CONFIG_SOCK_CGROUP_DATA |
645 | ||
bd1060a1 TH |
646 | /* |
647 | * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains | |
648 | * per-socket cgroup information except for memcg association. | |
649 | * | |
650 | * On legacy hierarchies, net_prio and net_cls controllers directly set | |
651 | * attributes on each sock which can then be tested by the network layer. | |
652 | * On the default hierarchy, each sock is associated with the cgroup it was | |
653 | * created in and the networking layer can match the cgroup directly. | |
654 | * | |
655 | * To avoid carrying all three cgroup related fields separately in sock, | |
656 | * sock_cgroup_data overloads (prioidx, classid) and the cgroup pointer. | |
657 | * On boot, sock_cgroup_data records the cgroup that the sock was created | |
658 | * in so that cgroup2 matches can be made; however, once either net_prio or | |
659 | * net_cls starts being used, the area is overriden to carry prioidx and/or | |
660 | * classid. The two modes are distinguished by whether the lowest bit is | |
661 | * set. Clear bit indicates cgroup pointer while set bit prioidx and | |
662 | * classid. | |
663 | * | |
664 | * While userland may start using net_prio or net_cls at any time, once | |
665 | * either is used, cgroup2 matching no longer works. There is no reason to | |
666 | * mix the two and this is in line with how legacy and v2 compatibility is | |
667 | * handled. On mode switch, cgroup references which are already being | |
668 | * pointed to by socks may be leaked. While this can be remedied by adding | |
669 | * synchronization around sock_cgroup_data, given that the number of leaked | |
670 | * cgroups is bound and highly unlikely to be high, this seems to be the | |
671 | * better trade-off. | |
672 | */ | |
2a56a1fe | 673 | struct sock_cgroup_data { |
bd1060a1 TH |
674 | union { |
675 | #ifdef __LITTLE_ENDIAN | |
676 | struct { | |
677 | u8 is_data; | |
678 | u8 padding; | |
679 | u16 prioidx; | |
680 | u32 classid; | |
681 | } __packed; | |
682 | #else | |
683 | struct { | |
684 | u32 classid; | |
685 | u16 prioidx; | |
686 | u8 padding; | |
687 | u8 is_data; | |
688 | } __packed; | |
689 | #endif | |
690 | u64 val; | |
691 | }; | |
2a56a1fe TH |
692 | }; |
693 | ||
bd1060a1 TH |
694 | /* |
695 | * There's a theoretical window where the following accessors race with | |
696 | * updaters and return part of the previous pointer as the prioidx or | |
697 | * classid. Such races are short-lived and the result isn't critical. | |
698 | */ | |
2a56a1fe TH |
699 | static inline u16 sock_cgroup_prioidx(struct sock_cgroup_data *skcd) |
700 | { | |
bd1060a1 TH |
701 | /* fallback to 1 which is always the ID of the root cgroup */ |
702 | return (skcd->is_data & 1) ? skcd->prioidx : 1; | |
2a56a1fe TH |
703 | } |
704 | ||
705 | static inline u32 sock_cgroup_classid(struct sock_cgroup_data *skcd) | |
706 | { | |
bd1060a1 TH |
707 | /* fallback to 0 which is the unconfigured default classid */ |
708 | return (skcd->is_data & 1) ? skcd->classid : 0; | |
2a56a1fe TH |
709 | } |
710 | ||
bd1060a1 TH |
711 | /* |
712 | * If invoked concurrently, the updaters may clobber each other. The | |
713 | * caller is responsible for synchronization. | |
714 | */ | |
2a56a1fe TH |
715 | static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, |
716 | u16 prioidx) | |
717 | { | |
ad2c8c73 | 718 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
719 | |
720 | if (sock_cgroup_prioidx(&skcd_buf) == prioidx) | |
721 | return; | |
722 | ||
723 | if (!(skcd_buf.is_data & 1)) { | |
724 | skcd_buf.val = 0; | |
725 | skcd_buf.is_data = 1; | |
726 | } | |
727 | ||
728 | skcd_buf.prioidx = prioidx; | |
729 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
730 | } |
731 | ||
732 | static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, | |
733 | u32 classid) | |
734 | { | |
ad2c8c73 | 735 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
736 | |
737 | if (sock_cgroup_classid(&skcd_buf) == classid) | |
738 | return; | |
739 | ||
740 | if (!(skcd_buf.is_data & 1)) { | |
741 | skcd_buf.val = 0; | |
742 | skcd_buf.is_data = 1; | |
743 | } | |
744 | ||
745 | skcd_buf.classid = classid; | |
746 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
747 | } |
748 | ||
749 | #else /* CONFIG_SOCK_CGROUP_DATA */ | |
750 | ||
751 | struct sock_cgroup_data { | |
752 | }; | |
753 | ||
754 | #endif /* CONFIG_SOCK_CGROUP_DATA */ | |
755 | ||
b4a04ab7 | 756 | #endif /* _LINUX_CGROUP_DEFS_H */ |