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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 PM |
181 | |
182 | /* pids_mutex protects the fields below */ | |
183 | struct rw_semaphore pids_mutex; | |
184 | /* Array of process ids in the cgroup */ | |
185 | pid_t *tasks_pids; | |
186 | /* How many files are using the current tasks_pids array */ | |
187 | int pids_use_count; | |
188 | /* Length of the current tasks_pids array */ | |
189 | int pids_length; | |
a47295e6 PM |
190 | |
191 | /* For RCU-protected deletion */ | |
192 | struct rcu_head rcu_head; | |
817929ec PM |
193 | }; |
194 | ||
d20a390a PM |
195 | /* |
196 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
197 | * cgroup_subsys_state objects. This saves space in the task struct |
198 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
199 | * list_add()/del() can bump the reference count on the entire cgroup |
200 | * set for a task. | |
817929ec PM |
201 | */ |
202 | ||
203 | struct css_set { | |
204 | ||
205 | /* Reference count */ | |
146aa1bd | 206 | atomic_t refcount; |
817929ec | 207 | |
472b1053 LZ |
208 | /* |
209 | * List running through all cgroup groups in the same hash | |
210 | * slot. Protected by css_set_lock | |
211 | */ | |
212 | struct hlist_node hlist; | |
213 | ||
817929ec PM |
214 | /* |
215 | * List running through all tasks using this cgroup | |
216 | * group. Protected by css_set_lock | |
217 | */ | |
218 | struct list_head tasks; | |
219 | ||
220 | /* | |
221 | * List of cg_cgroup_link objects on link chains from | |
222 | * cgroups referenced from this css_set. Protected by | |
223 | * css_set_lock | |
224 | */ | |
225 | struct list_head cg_links; | |
226 | ||
227 | /* | |
228 | * Set of subsystem states, one for each subsystem. This array | |
229 | * is immutable after creation apart from the init_css_set | |
230 | * during subsystem registration (at boot time). | |
231 | */ | |
232 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
ddbcc7e8 PM |
233 | }; |
234 | ||
91796569 PM |
235 | /* |
236 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
237 | * control files | |
238 | */ | |
239 | ||
240 | struct cgroup_map_cb { | |
241 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
242 | void *state; | |
243 | }; | |
244 | ||
d20a390a PM |
245 | /* |
246 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
247 | * |
248 | * When reading/writing to a file: | |
a043e3b2 | 249 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
250 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
251 | */ | |
252 | ||
253 | #define MAX_CFTYPE_NAME 64 | |
254 | struct cftype { | |
d20a390a PM |
255 | /* |
256 | * By convention, the name should begin with the name of the | |
257 | * subsystem, followed by a period | |
258 | */ | |
ddbcc7e8 PM |
259 | char name[MAX_CFTYPE_NAME]; |
260 | int private; | |
099fca32 LZ |
261 | /* |
262 | * If not 0, file mode is set to this value, otherwise it will | |
263 | * be figured out automatically | |
264 | */ | |
265 | mode_t mode; | |
db3b1497 PM |
266 | |
267 | /* | |
268 | * If non-zero, defines the maximum length of string that can | |
269 | * be passed to write_string; defaults to 64 | |
270 | */ | |
271 | size_t max_write_len; | |
272 | ||
ce16b49d PM |
273 | int (*open)(struct inode *inode, struct file *file); |
274 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
275 | struct file *file, | |
276 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 277 | /* |
f4c753b7 | 278 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
279 | * single integer. Use it in place of read() |
280 | */ | |
ce16b49d | 281 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
282 | /* |
283 | * read_s64() is a signed version of read_u64() | |
284 | */ | |
ce16b49d | 285 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
286 | /* |
287 | * read_map() is used for defining a map of key/value | |
288 | * pairs. It should call cb->fill(cb, key, value) for each | |
289 | * entry. The key/value pairs (and their ordering) should not | |
290 | * change between reboots. | |
291 | */ | |
ce16b49d PM |
292 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
293 | struct cgroup_map_cb *cb); | |
29486df3 SH |
294 | /* |
295 | * read_seq_string() is used for outputting a simple sequence | |
296 | * using seqfile. | |
297 | */ | |
ce16b49d PM |
298 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
299 | struct seq_file *m); | |
91796569 | 300 | |
ce16b49d PM |
301 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
302 | struct file *file, | |
303 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
304 | |
305 | /* | |
f4c753b7 | 306 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
307 | * a single integer (as parsed by simple_strtoull) from |
308 | * userspace. Use in place of write(); return 0 or error. | |
309 | */ | |
ce16b49d | 310 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
311 | /* |
312 | * write_s64() is a signed version of write_u64() | |
313 | */ | |
ce16b49d | 314 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 315 | |
db3b1497 PM |
316 | /* |
317 | * write_string() is passed a nul-terminated kernelspace | |
318 | * buffer of maximum length determined by max_write_len. | |
319 | * Returns 0 or -ve error code. | |
320 | */ | |
321 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
322 | const char *buffer); | |
d447ea2f PE |
323 | /* |
324 | * trigger() callback can be used to get some kick from the | |
325 | * userspace, when the actual string written is not important | |
326 | * at all. The private field can be used to determine the | |
327 | * kick type for multiplexing. | |
328 | */ | |
329 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
330 | ||
ce16b49d | 331 | int (*release)(struct inode *inode, struct file *file); |
ddbcc7e8 PM |
332 | }; |
333 | ||
31a7df01 CW |
334 | struct cgroup_scanner { |
335 | struct cgroup *cg; | |
336 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
337 | void (*process_task)(struct task_struct *p, | |
338 | struct cgroup_scanner *scan); | |
339 | struct ptr_heap *heap; | |
bd1a8ab7 | 340 | void *data; |
31a7df01 CW |
341 | }; |
342 | ||
d20a390a PM |
343 | /* |
344 | * Add a new file to the given cgroup directory. Should only be | |
345 | * called by subsystems from within a populate() method | |
346 | */ | |
ffd2d883 | 347 | int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, |
ddbcc7e8 PM |
348 | const struct cftype *cft); |
349 | ||
d20a390a PM |
350 | /* |
351 | * Add a set of new files to the given cgroup directory. Should | |
352 | * only be called by subsystems from within a populate() method | |
353 | */ | |
ffd2d883 | 354 | int cgroup_add_files(struct cgroup *cgrp, |
ddbcc7e8 PM |
355 | struct cgroup_subsys *subsys, |
356 | const struct cftype cft[], | |
357 | int count); | |
358 | ||
ffd2d883 | 359 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 360 | |
ffd2d883 | 361 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 362 | |
ffd2d883 | 363 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 364 | |
313e924c GN |
365 | /* Return true if cgrp is a descendant of the task's cgroup */ |
366 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); | |
ddbcc7e8 | 367 | |
21acb9ca TLSC |
368 | /* |
369 | * Control Group subsystem type. | |
370 | * See Documentation/cgroups/cgroups.txt for details | |
371 | */ | |
ddbcc7e8 PM |
372 | |
373 | struct cgroup_subsys { | |
374 | struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, | |
ffd2d883 | 375 | struct cgroup *cgrp); |
ec64f515 | 376 | int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
ffd2d883 | 377 | void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
ddbcc7e8 | 378 | int (*can_attach)(struct cgroup_subsys *ss, |
ffd2d883 LZ |
379 | struct cgroup *cgrp, struct task_struct *tsk); |
380 | void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
381 | struct cgroup *old_cgrp, struct task_struct *tsk); | |
ddbcc7e8 PM |
382 | void (*fork)(struct cgroup_subsys *ss, struct task_struct *task); |
383 | void (*exit)(struct cgroup_subsys *ss, struct task_struct *task); | |
384 | int (*populate)(struct cgroup_subsys *ss, | |
ffd2d883 LZ |
385 | struct cgroup *cgrp); |
386 | void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
ddbcc7e8 | 387 | void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
e5991371 | 388 | |
ddbcc7e8 PM |
389 | int subsys_id; |
390 | int active; | |
8bab8dde | 391 | int disabled; |
ddbcc7e8 | 392 | int early_init; |
38460b48 KH |
393 | /* |
394 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
395 | * (not available in early_init time.) | |
396 | */ | |
397 | bool use_id; | |
ddbcc7e8 PM |
398 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
399 | const char *name; | |
400 | ||
999cd8a4 PM |
401 | /* |
402 | * Protects sibling/children links of cgroups in this | |
403 | * hierarchy, plus protects which hierarchy (or none) the | |
404 | * subsystem is a part of (i.e. root/sibling). To avoid | |
405 | * potential deadlocks, the following operations should not be | |
406 | * undertaken while holding any hierarchy_mutex: | |
407 | * | |
408 | * - allocating memory | |
409 | * - initiating hotplug events | |
410 | */ | |
411 | struct mutex hierarchy_mutex; | |
cfebe563 | 412 | struct lock_class_key subsys_key; |
ddbcc7e8 | 413 | |
999cd8a4 PM |
414 | /* |
415 | * Link to parent, and list entry in parent's children. | |
416 | * Protected by this->hierarchy_mutex and cgroup_lock() | |
417 | */ | |
418 | struct cgroupfs_root *root; | |
ddbcc7e8 | 419 | struct list_head sibling; |
38460b48 KH |
420 | /* used when use_id == true */ |
421 | struct idr idr; | |
422 | spinlock_t id_lock; | |
ddbcc7e8 PM |
423 | }; |
424 | ||
425 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
426 | #include <linux/cgroup_subsys.h> | |
427 | #undef SUBSYS | |
428 | ||
429 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 430 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 431 | { |
ffd2d883 | 432 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
433 | } |
434 | ||
435 | static inline struct cgroup_subsys_state *task_subsys_state( | |
436 | struct task_struct *task, int subsys_id) | |
437 | { | |
817929ec | 438 | return rcu_dereference(task->cgroups->subsys[subsys_id]); |
ddbcc7e8 PM |
439 | } |
440 | ||
441 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
442 | int subsys_id) | |
443 | { | |
444 | return task_subsys_state(task, subsys_id)->cgroup; | |
445 | } | |
446 | ||
e885dcde SH |
447 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss, |
448 | char *nodename); | |
697f4161 | 449 | |
817929ec PM |
450 | /* A cgroup_iter should be treated as an opaque object */ |
451 | struct cgroup_iter { | |
452 | struct list_head *cg_link; | |
453 | struct list_head *task; | |
454 | }; | |
455 | ||
d20a390a PM |
456 | /* |
457 | * To iterate across the tasks in a cgroup: | |
817929ec PM |
458 | * |
459 | * 1) call cgroup_iter_start to intialize an iterator | |
460 | * | |
461 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
462 | * returns NULL or until you want to end the iteration | |
463 | * | |
464 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 465 | * |
d20a390a PM |
466 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
467 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
468 | * the test_task() callback, but not while calling the process_task() | |
469 | * callback. | |
817929ec | 470 | */ |
ffd2d883 LZ |
471 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
472 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 473 | struct cgroup_iter *it); |
ffd2d883 | 474 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 475 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 476 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
817929ec | 477 | |
38460b48 KH |
478 | /* |
479 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
480 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
481 | * CSS ID is assigned at cgroup allocation (create) automatically | |
482 | * and removed when subsys calls free_css_id() function. This is because | |
483 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
484 | * | |
485 | * Looking up and scanning function should be called under rcu_read_lock(). | |
486 | * Taking cgroup_mutex()/hierarchy_mutex() is not necessary for following calls. | |
487 | * But the css returned by this routine can be "not populated yet" or "being | |
488 | * destroyed". The caller should check css and cgroup's status. | |
489 | */ | |
490 | ||
491 | /* | |
492 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
493 | * cgroup_subsys_state. | |
494 | */ | |
495 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
496 | ||
497 | /* Find a cgroup_subsys_state which has given ID */ | |
498 | ||
499 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
500 | ||
501 | /* | |
502 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
503 | * Returning a cgroup_subsys_state or NULL. | |
504 | */ | |
505 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
506 | struct cgroup_subsys_state *root, int *foundid); | |
507 | ||
508 | /* Returns true if root is ancestor of cg */ | |
509 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 510 | const struct cgroup_subsys_state *root); |
38460b48 KH |
511 | |
512 | /* Get id and depth of css */ | |
513 | unsigned short css_id(struct cgroup_subsys_state *css); | |
514 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
515 | ||
ddbcc7e8 PM |
516 | #else /* !CONFIG_CGROUPS */ |
517 | ||
518 | static inline int cgroup_init_early(void) { return 0; } | |
519 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
520 | static inline void cgroup_fork(struct task_struct *p) {} |
521 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 522 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 523 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
524 | |
525 | static inline void cgroup_lock(void) {} | |
526 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
527 | static inline int cgroupstats_build(struct cgroupstats *stats, |
528 | struct dentry *dentry) | |
529 | { | |
530 | return -EINVAL; | |
531 | } | |
ddbcc7e8 PM |
532 | |
533 | #endif /* !CONFIG_CGROUPS */ | |
534 | ||
535 | #endif /* _LINUX_CGROUP_H */ |