Commit | Line | Data |
---|---|---|
ddbcc7e8 PM |
1 | #ifndef _LINUX_CGROUP_H |
2 | #define _LINUX_CGROUP_H | |
3 | /* | |
4 | * cgroup interface | |
5 | * | |
6 | * Copyright (C) 2003 BULL SA | |
7 | * Copyright (C) 2004-2006 Silicon Graphics, Inc. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/sched.h> | |
ddbcc7e8 PM |
12 | #include <linux/cpumask.h> |
13 | #include <linux/nodemask.h> | |
14 | #include <linux/rcupdate.h> | |
846c7bb0 | 15 | #include <linux/cgroupstats.h> |
31a7df01 | 16 | #include <linux/prio_heap.h> |
cc31edce | 17 | #include <linux/rwsem.h> |
38460b48 | 18 | #include <linux/idr.h> |
ddbcc7e8 PM |
19 | |
20 | #ifdef CONFIG_CGROUPS | |
21 | ||
22 | struct cgroupfs_root; | |
23 | struct cgroup_subsys; | |
24 | struct inode; | |
84eea842 | 25 | struct cgroup; |
38460b48 | 26 | struct css_id; |
ddbcc7e8 PM |
27 | |
28 | extern int cgroup_init_early(void); | |
29 | extern int cgroup_init(void); | |
ddbcc7e8 | 30 | extern void cgroup_lock(void); |
84eea842 | 31 | extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
ddbcc7e8 | 32 | extern void cgroup_unlock(void); |
b4f48b63 PM |
33 | extern void cgroup_fork(struct task_struct *p); |
34 | extern void cgroup_fork_callbacks(struct task_struct *p); | |
817929ec | 35 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 36 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
37 | extern int cgroupstats_build(struct cgroupstats *stats, |
38 | struct dentry *dentry); | |
ddbcc7e8 | 39 | |
a424316c PM |
40 | extern struct file_operations proc_cgroup_operations; |
41 | ||
817929ec PM |
42 | /* Define the enumeration of all cgroup subsystems */ |
43 | #define SUBSYS(_x) _x ## _subsys_id, | |
44 | enum cgroup_subsys_id { | |
45 | #include <linux/cgroup_subsys.h> | |
46 | CGROUP_SUBSYS_COUNT | |
47 | }; | |
48 | #undef SUBSYS | |
49 | ||
ddbcc7e8 PM |
50 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
51 | struct cgroup_subsys_state { | |
d20a390a PM |
52 | /* |
53 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 54 | * for subsystems that want to know about the cgroup |
d20a390a PM |
55 | * hierarchy structure |
56 | */ | |
ddbcc7e8 PM |
57 | struct cgroup *cgroup; |
58 | ||
d20a390a PM |
59 | /* |
60 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 61 | * to be "busy". Should be accessed via css_get(), |
d20a390a PM |
62 | * css_tryget() and and css_put(). |
63 | */ | |
ddbcc7e8 PM |
64 | |
65 | atomic_t refcnt; | |
66 | ||
67 | unsigned long flags; | |
38460b48 KH |
68 | /* ID for this css, if possible */ |
69 | struct css_id *id; | |
ddbcc7e8 PM |
70 | }; |
71 | ||
72 | /* bits in struct cgroup_subsys_state flags field */ | |
73 | enum { | |
74 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
e7c5ec91 | 75 | CSS_REMOVED, /* This CSS is dead */ |
ddbcc7e8 PM |
76 | }; |
77 | ||
78 | /* | |
e7c5ec91 PM |
79 | * Call css_get() to hold a reference on the css; it can be used |
80 | * for a reference obtained via: | |
81 | * - an existing ref-counted reference to the css | |
82 | * - task->cgroups for a locked task | |
ddbcc7e8 PM |
83 | */ |
84 | ||
85 | static inline void css_get(struct cgroup_subsys_state *css) | |
86 | { | |
87 | /* We don't need to reference count the root state */ | |
88 | if (!test_bit(CSS_ROOT, &css->flags)) | |
89 | atomic_inc(&css->refcnt); | |
90 | } | |
e7c5ec91 PM |
91 | |
92 | static inline bool css_is_removed(struct cgroup_subsys_state *css) | |
93 | { | |
94 | return test_bit(CSS_REMOVED, &css->flags); | |
95 | } | |
96 | ||
97 | /* | |
98 | * Call css_tryget() to take a reference on a css if your existing | |
99 | * (known-valid) reference isn't already ref-counted. Returns false if | |
100 | * the css has been destroyed. | |
101 | */ | |
102 | ||
103 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
104 | { | |
105 | if (test_bit(CSS_ROOT, &css->flags)) | |
106 | return true; | |
107 | while (!atomic_inc_not_zero(&css->refcnt)) { | |
108 | if (test_bit(CSS_REMOVED, &css->flags)) | |
109 | return false; | |
804b3c28 | 110 | cpu_relax(); |
e7c5ec91 PM |
111 | } |
112 | return true; | |
113 | } | |
114 | ||
ddbcc7e8 PM |
115 | /* |
116 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 117 | * css_get() or css_tryget() |
ddbcc7e8 PM |
118 | */ |
119 | ||
81a6a5cd | 120 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
121 | static inline void css_put(struct cgroup_subsys_state *css) |
122 | { | |
123 | if (!test_bit(CSS_ROOT, &css->flags)) | |
81a6a5cd | 124 | __css_put(css); |
ddbcc7e8 PM |
125 | } |
126 | ||
3116f0e3 PM |
127 | /* bits in struct cgroup flags field */ |
128 | enum { | |
129 | /* Control Group is dead */ | |
130 | CGRP_REMOVED, | |
d20a390a PM |
131 | /* |
132 | * Control Group has previously had a child cgroup or a task, | |
133 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
134 | */ | |
3116f0e3 PM |
135 | CGRP_RELEASABLE, |
136 | /* Control Group requires release notifications to userspace */ | |
137 | CGRP_NOTIFY_ON_RELEASE, | |
ec64f515 KH |
138 | /* |
139 | * A thread in rmdir() is wating for this cgroup. | |
140 | */ | |
141 | CGRP_WAIT_ON_RMDIR, | |
3116f0e3 PM |
142 | }; |
143 | ||
ddbcc7e8 PM |
144 | struct cgroup { |
145 | unsigned long flags; /* "unsigned long" so bitops work */ | |
146 | ||
d20a390a PM |
147 | /* |
148 | * count users of this cgroup. >0 means busy, but doesn't | |
149 | * necessarily indicate the number of tasks in the cgroup | |
150 | */ | |
ddbcc7e8 PM |
151 | atomic_t count; |
152 | ||
153 | /* | |
154 | * We link our 'sibling' struct into our parent's 'children'. | |
155 | * Our children link their 'sibling' into our 'children'. | |
156 | */ | |
157 | struct list_head sibling; /* my parent's children */ | |
158 | struct list_head children; /* my children */ | |
159 | ||
d20a390a | 160 | struct cgroup *parent; /* my parent */ |
a47295e6 | 161 | struct dentry *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 PM |
162 | |
163 | /* Private pointers for each registered subsystem */ | |
164 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
165 | ||
166 | struct cgroupfs_root *root; | |
167 | struct cgroup *top_cgroup; | |
817929ec PM |
168 | |
169 | /* | |
170 | * List of cg_cgroup_links pointing at css_sets with | |
171 | * tasks in this cgroup. Protected by css_set_lock | |
172 | */ | |
173 | struct list_head css_sets; | |
81a6a5cd PM |
174 | |
175 | /* | |
176 | * Linked list running through all cgroups that can | |
177 | * potentially be reaped by the release agent. Protected by | |
178 | * release_list_lock | |
179 | */ | |
180 | struct list_head release_list; | |
cc31edce | 181 | |
096b7fe0 | 182 | /* pids_mutex protects pids_list and cached pid arrays. */ |
cc31edce | 183 | struct rw_semaphore pids_mutex; |
096b7fe0 LZ |
184 | |
185 | /* Linked list of struct cgroup_pids */ | |
186 | struct list_head pids_list; | |
a47295e6 PM |
187 | |
188 | /* For RCU-protected deletion */ | |
189 | struct rcu_head rcu_head; | |
817929ec PM |
190 | }; |
191 | ||
d20a390a PM |
192 | /* |
193 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
194 | * cgroup_subsys_state objects. This saves space in the task struct |
195 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
196 | * list_add()/del() can bump the reference count on the entire cgroup |
197 | * set for a task. | |
817929ec PM |
198 | */ |
199 | ||
200 | struct css_set { | |
201 | ||
202 | /* Reference count */ | |
146aa1bd | 203 | atomic_t refcount; |
817929ec | 204 | |
472b1053 LZ |
205 | /* |
206 | * List running through all cgroup groups in the same hash | |
207 | * slot. Protected by css_set_lock | |
208 | */ | |
209 | struct hlist_node hlist; | |
210 | ||
817929ec PM |
211 | /* |
212 | * List running through all tasks using this cgroup | |
213 | * group. Protected by css_set_lock | |
214 | */ | |
215 | struct list_head tasks; | |
216 | ||
217 | /* | |
218 | * List of cg_cgroup_link objects on link chains from | |
219 | * cgroups referenced from this css_set. Protected by | |
220 | * css_set_lock | |
221 | */ | |
222 | struct list_head cg_links; | |
223 | ||
224 | /* | |
225 | * Set of subsystem states, one for each subsystem. This array | |
226 | * is immutable after creation apart from the init_css_set | |
227 | * during subsystem registration (at boot time). | |
228 | */ | |
229 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
ddbcc7e8 PM |
230 | }; |
231 | ||
91796569 PM |
232 | /* |
233 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
234 | * control files | |
235 | */ | |
236 | ||
237 | struct cgroup_map_cb { | |
238 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
239 | void *state; | |
240 | }; | |
241 | ||
d20a390a PM |
242 | /* |
243 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
244 | * |
245 | * When reading/writing to a file: | |
a043e3b2 | 246 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
247 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
248 | */ | |
249 | ||
250 | #define MAX_CFTYPE_NAME 64 | |
251 | struct cftype { | |
d20a390a PM |
252 | /* |
253 | * By convention, the name should begin with the name of the | |
254 | * subsystem, followed by a period | |
255 | */ | |
ddbcc7e8 PM |
256 | char name[MAX_CFTYPE_NAME]; |
257 | int private; | |
099fca32 LZ |
258 | /* |
259 | * If not 0, file mode is set to this value, otherwise it will | |
260 | * be figured out automatically | |
261 | */ | |
262 | mode_t mode; | |
db3b1497 PM |
263 | |
264 | /* | |
265 | * If non-zero, defines the maximum length of string that can | |
266 | * be passed to write_string; defaults to 64 | |
267 | */ | |
268 | size_t max_write_len; | |
269 | ||
ce16b49d PM |
270 | int (*open)(struct inode *inode, struct file *file); |
271 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
272 | struct file *file, | |
273 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 274 | /* |
f4c753b7 | 275 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
276 | * single integer. Use it in place of read() |
277 | */ | |
ce16b49d | 278 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
279 | /* |
280 | * read_s64() is a signed version of read_u64() | |
281 | */ | |
ce16b49d | 282 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
283 | /* |
284 | * read_map() is used for defining a map of key/value | |
285 | * pairs. It should call cb->fill(cb, key, value) for each | |
286 | * entry. The key/value pairs (and their ordering) should not | |
287 | * change between reboots. | |
288 | */ | |
ce16b49d PM |
289 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
290 | struct cgroup_map_cb *cb); | |
29486df3 SH |
291 | /* |
292 | * read_seq_string() is used for outputting a simple sequence | |
293 | * using seqfile. | |
294 | */ | |
ce16b49d PM |
295 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
296 | struct seq_file *m); | |
91796569 | 297 | |
ce16b49d PM |
298 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
299 | struct file *file, | |
300 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
301 | |
302 | /* | |
f4c753b7 | 303 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
304 | * a single integer (as parsed by simple_strtoull) from |
305 | * userspace. Use in place of write(); return 0 or error. | |
306 | */ | |
ce16b49d | 307 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
308 | /* |
309 | * write_s64() is a signed version of write_u64() | |
310 | */ | |
ce16b49d | 311 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 312 | |
db3b1497 PM |
313 | /* |
314 | * write_string() is passed a nul-terminated kernelspace | |
315 | * buffer of maximum length determined by max_write_len. | |
316 | * Returns 0 or -ve error code. | |
317 | */ | |
318 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
319 | const char *buffer); | |
d447ea2f PE |
320 | /* |
321 | * trigger() callback can be used to get some kick from the | |
322 | * userspace, when the actual string written is not important | |
323 | * at all. The private field can be used to determine the | |
324 | * kick type for multiplexing. | |
325 | */ | |
326 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
327 | ||
ce16b49d | 328 | int (*release)(struct inode *inode, struct file *file); |
ddbcc7e8 PM |
329 | }; |
330 | ||
31a7df01 CW |
331 | struct cgroup_scanner { |
332 | struct cgroup *cg; | |
333 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
334 | void (*process_task)(struct task_struct *p, | |
335 | struct cgroup_scanner *scan); | |
336 | struct ptr_heap *heap; | |
bd1a8ab7 | 337 | void *data; |
31a7df01 CW |
338 | }; |
339 | ||
d20a390a PM |
340 | /* |
341 | * Add a new file to the given cgroup directory. Should only be | |
342 | * called by subsystems from within a populate() method | |
343 | */ | |
ffd2d883 | 344 | int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, |
ddbcc7e8 PM |
345 | const struct cftype *cft); |
346 | ||
d20a390a PM |
347 | /* |
348 | * Add a set of new files to the given cgroup directory. Should | |
349 | * only be called by subsystems from within a populate() method | |
350 | */ | |
ffd2d883 | 351 | int cgroup_add_files(struct cgroup *cgrp, |
ddbcc7e8 PM |
352 | struct cgroup_subsys *subsys, |
353 | const struct cftype cft[], | |
354 | int count); | |
355 | ||
ffd2d883 | 356 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 357 | |
ffd2d883 | 358 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 359 | |
ffd2d883 | 360 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 361 | |
313e924c GN |
362 | /* Return true if cgrp is a descendant of the task's cgroup */ |
363 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); | |
ddbcc7e8 | 364 | |
88703267 KH |
365 | /* |
366 | * When the subsys has to access css and may add permanent refcnt to css, | |
367 | * it should take care of racy conditions with rmdir(). Following set of | |
368 | * functions, is for stop/restart rmdir if necessary. | |
369 | * Because these will call css_get/put, "css" should be alive css. | |
370 | * | |
371 | * cgroup_exclude_rmdir(); | |
372 | * ...do some jobs which may access arbitrary empty cgroup | |
373 | * cgroup_release_and_wakeup_rmdir(); | |
374 | * | |
375 | * When someone removes a cgroup while cgroup_exclude_rmdir() holds it, | |
376 | * it sleeps and cgroup_release_and_wakeup_rmdir() will wake him up. | |
377 | */ | |
378 | ||
379 | void cgroup_exclude_rmdir(struct cgroup_subsys_state *css); | |
380 | void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css); | |
381 | ||
21acb9ca TLSC |
382 | /* |
383 | * Control Group subsystem type. | |
384 | * See Documentation/cgroups/cgroups.txt for details | |
385 | */ | |
ddbcc7e8 PM |
386 | |
387 | struct cgroup_subsys { | |
388 | struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, | |
ffd2d883 | 389 | struct cgroup *cgrp); |
ec64f515 | 390 | int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
ffd2d883 | 391 | void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
ddbcc7e8 | 392 | int (*can_attach)(struct cgroup_subsys *ss, |
ffd2d883 LZ |
393 | struct cgroup *cgrp, struct task_struct *tsk); |
394 | void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
395 | struct cgroup *old_cgrp, struct task_struct *tsk); | |
ddbcc7e8 PM |
396 | void (*fork)(struct cgroup_subsys *ss, struct task_struct *task); |
397 | void (*exit)(struct cgroup_subsys *ss, struct task_struct *task); | |
398 | int (*populate)(struct cgroup_subsys *ss, | |
ffd2d883 LZ |
399 | struct cgroup *cgrp); |
400 | void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
ddbcc7e8 | 401 | void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
e5991371 | 402 | |
ddbcc7e8 PM |
403 | int subsys_id; |
404 | int active; | |
8bab8dde | 405 | int disabled; |
ddbcc7e8 | 406 | int early_init; |
38460b48 KH |
407 | /* |
408 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
409 | * (not available in early_init time.) | |
410 | */ | |
411 | bool use_id; | |
ddbcc7e8 PM |
412 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
413 | const char *name; | |
414 | ||
999cd8a4 PM |
415 | /* |
416 | * Protects sibling/children links of cgroups in this | |
417 | * hierarchy, plus protects which hierarchy (or none) the | |
418 | * subsystem is a part of (i.e. root/sibling). To avoid | |
419 | * potential deadlocks, the following operations should not be | |
420 | * undertaken while holding any hierarchy_mutex: | |
421 | * | |
422 | * - allocating memory | |
423 | * - initiating hotplug events | |
424 | */ | |
425 | struct mutex hierarchy_mutex; | |
cfebe563 | 426 | struct lock_class_key subsys_key; |
ddbcc7e8 | 427 | |
999cd8a4 PM |
428 | /* |
429 | * Link to parent, and list entry in parent's children. | |
430 | * Protected by this->hierarchy_mutex and cgroup_lock() | |
431 | */ | |
432 | struct cgroupfs_root *root; | |
ddbcc7e8 | 433 | struct list_head sibling; |
38460b48 KH |
434 | /* used when use_id == true */ |
435 | struct idr idr; | |
436 | spinlock_t id_lock; | |
ddbcc7e8 PM |
437 | }; |
438 | ||
439 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
440 | #include <linux/cgroup_subsys.h> | |
441 | #undef SUBSYS | |
442 | ||
443 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 444 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 445 | { |
ffd2d883 | 446 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
447 | } |
448 | ||
449 | static inline struct cgroup_subsys_state *task_subsys_state( | |
450 | struct task_struct *task, int subsys_id) | |
451 | { | |
817929ec | 452 | return rcu_dereference(task->cgroups->subsys[subsys_id]); |
ddbcc7e8 PM |
453 | } |
454 | ||
455 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
456 | int subsys_id) | |
457 | { | |
458 | return task_subsys_state(task, subsys_id)->cgroup; | |
459 | } | |
460 | ||
e885dcde SH |
461 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss, |
462 | char *nodename); | |
697f4161 | 463 | |
817929ec PM |
464 | /* A cgroup_iter should be treated as an opaque object */ |
465 | struct cgroup_iter { | |
466 | struct list_head *cg_link; | |
467 | struct list_head *task; | |
468 | }; | |
469 | ||
d20a390a PM |
470 | /* |
471 | * To iterate across the tasks in a cgroup: | |
817929ec PM |
472 | * |
473 | * 1) call cgroup_iter_start to intialize an iterator | |
474 | * | |
475 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
476 | * returns NULL or until you want to end the iteration | |
477 | * | |
478 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 479 | * |
d20a390a PM |
480 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
481 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
482 | * the test_task() callback, but not while calling the process_task() | |
483 | * callback. | |
817929ec | 484 | */ |
ffd2d883 LZ |
485 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
486 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 487 | struct cgroup_iter *it); |
ffd2d883 | 488 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 489 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 490 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
817929ec | 491 | |
38460b48 KH |
492 | /* |
493 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
494 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
495 | * CSS ID is assigned at cgroup allocation (create) automatically | |
496 | * and removed when subsys calls free_css_id() function. This is because | |
497 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
498 | * | |
499 | * Looking up and scanning function should be called under rcu_read_lock(). | |
500 | * Taking cgroup_mutex()/hierarchy_mutex() is not necessary for following calls. | |
501 | * But the css returned by this routine can be "not populated yet" or "being | |
502 | * destroyed". The caller should check css and cgroup's status. | |
503 | */ | |
504 | ||
505 | /* | |
506 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
507 | * cgroup_subsys_state. | |
508 | */ | |
509 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
510 | ||
511 | /* Find a cgroup_subsys_state which has given ID */ | |
512 | ||
513 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
514 | ||
515 | /* | |
516 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
517 | * Returning a cgroup_subsys_state or NULL. | |
518 | */ | |
519 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
520 | struct cgroup_subsys_state *root, int *foundid); | |
521 | ||
522 | /* Returns true if root is ancestor of cg */ | |
523 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 524 | const struct cgroup_subsys_state *root); |
38460b48 KH |
525 | |
526 | /* Get id and depth of css */ | |
527 | unsigned short css_id(struct cgroup_subsys_state *css); | |
528 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
529 | ||
ddbcc7e8 PM |
530 | #else /* !CONFIG_CGROUPS */ |
531 | ||
532 | static inline int cgroup_init_early(void) { return 0; } | |
533 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
534 | static inline void cgroup_fork(struct task_struct *p) {} |
535 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 536 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 537 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
538 | |
539 | static inline void cgroup_lock(void) {} | |
540 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
541 | static inline int cgroupstats_build(struct cgroupstats *stats, |
542 | struct dentry *dentry) | |
543 | { | |
544 | return -EINVAL; | |
545 | } | |
ddbcc7e8 PM |
546 | |
547 | #endif /* !CONFIG_CGROUPS */ | |
548 | ||
549 | #endif /* _LINUX_CGROUP_H */ |