]>
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); |
d11c563d | 31 | extern int cgroup_lock_is_held(void); |
84eea842 | 32 | extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
ddbcc7e8 | 33 | extern void cgroup_unlock(void); |
b4f48b63 PM |
34 | extern void cgroup_fork(struct task_struct *p); |
35 | extern void cgroup_fork_callbacks(struct task_struct *p); | |
817929ec | 36 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 37 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
38 | extern int cgroupstats_build(struct cgroupstats *stats, |
39 | struct dentry *dentry); | |
e6a1105b | 40 | extern int cgroup_load_subsys(struct cgroup_subsys *ss); |
ddbcc7e8 | 41 | |
828c0950 | 42 | extern const struct file_operations proc_cgroup_operations; |
a424316c | 43 | |
aae8aab4 | 44 | /* Define the enumeration of all builtin cgroup subsystems */ |
817929ec PM |
45 | #define SUBSYS(_x) _x ## _subsys_id, |
46 | enum cgroup_subsys_id { | |
47 | #include <linux/cgroup_subsys.h> | |
aae8aab4 | 48 | CGROUP_BUILTIN_SUBSYS_COUNT |
817929ec PM |
49 | }; |
50 | #undef SUBSYS | |
aae8aab4 BB |
51 | /* |
52 | * This define indicates the maximum number of subsystems that can be loaded | |
53 | * at once. We limit to this many since cgroupfs_root has subsys_bits to keep | |
54 | * track of all of them. | |
55 | */ | |
56 | #define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long)) | |
817929ec | 57 | |
ddbcc7e8 PM |
58 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
59 | struct cgroup_subsys_state { | |
d20a390a PM |
60 | /* |
61 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 62 | * for subsystems that want to know about the cgroup |
d20a390a PM |
63 | * hierarchy structure |
64 | */ | |
ddbcc7e8 PM |
65 | struct cgroup *cgroup; |
66 | ||
d20a390a PM |
67 | /* |
68 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 69 | * to be "busy". Should be accessed via css_get(), |
d20a390a PM |
70 | * css_tryget() and and css_put(). |
71 | */ | |
ddbcc7e8 PM |
72 | |
73 | atomic_t refcnt; | |
74 | ||
75 | unsigned long flags; | |
38460b48 KH |
76 | /* ID for this css, if possible */ |
77 | struct css_id *id; | |
ddbcc7e8 PM |
78 | }; |
79 | ||
80 | /* bits in struct cgroup_subsys_state flags field */ | |
81 | enum { | |
82 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
e7c5ec91 | 83 | CSS_REMOVED, /* This CSS is dead */ |
ddbcc7e8 PM |
84 | }; |
85 | ||
d7b9fff7 DN |
86 | /* Caller must verify that the css is not for root cgroup */ |
87 | static inline void __css_get(struct cgroup_subsys_state *css, int count) | |
88 | { | |
89 | atomic_add(count, &css->refcnt); | |
90 | } | |
91 | ||
ddbcc7e8 | 92 | /* |
e7c5ec91 PM |
93 | * Call css_get() to hold a reference on the css; it can be used |
94 | * for a reference obtained via: | |
95 | * - an existing ref-counted reference to the css | |
96 | * - task->cgroups for a locked task | |
ddbcc7e8 PM |
97 | */ |
98 | ||
99 | static inline void css_get(struct cgroup_subsys_state *css) | |
100 | { | |
101 | /* We don't need to reference count the root state */ | |
102 | if (!test_bit(CSS_ROOT, &css->flags)) | |
d7b9fff7 | 103 | __css_get(css, 1); |
ddbcc7e8 | 104 | } |
e7c5ec91 PM |
105 | |
106 | static inline bool css_is_removed(struct cgroup_subsys_state *css) | |
107 | { | |
108 | return test_bit(CSS_REMOVED, &css->flags); | |
109 | } | |
110 | ||
111 | /* | |
112 | * Call css_tryget() to take a reference on a css if your existing | |
113 | * (known-valid) reference isn't already ref-counted. Returns false if | |
114 | * the css has been destroyed. | |
115 | */ | |
116 | ||
117 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
118 | { | |
119 | if (test_bit(CSS_ROOT, &css->flags)) | |
120 | return true; | |
121 | while (!atomic_inc_not_zero(&css->refcnt)) { | |
122 | if (test_bit(CSS_REMOVED, &css->flags)) | |
123 | return false; | |
804b3c28 | 124 | cpu_relax(); |
e7c5ec91 PM |
125 | } |
126 | return true; | |
127 | } | |
128 | ||
ddbcc7e8 PM |
129 | /* |
130 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 131 | * css_get() or css_tryget() |
ddbcc7e8 PM |
132 | */ |
133 | ||
d7b9fff7 | 134 | extern void __css_put(struct cgroup_subsys_state *css, int count); |
ddbcc7e8 PM |
135 | static inline void css_put(struct cgroup_subsys_state *css) |
136 | { | |
137 | if (!test_bit(CSS_ROOT, &css->flags)) | |
d7b9fff7 | 138 | __css_put(css, 1); |
ddbcc7e8 PM |
139 | } |
140 | ||
3116f0e3 PM |
141 | /* bits in struct cgroup flags field */ |
142 | enum { | |
143 | /* Control Group is dead */ | |
144 | CGRP_REMOVED, | |
d20a390a PM |
145 | /* |
146 | * Control Group has previously had a child cgroup or a task, | |
147 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
148 | */ | |
3116f0e3 PM |
149 | CGRP_RELEASABLE, |
150 | /* Control Group requires release notifications to userspace */ | |
151 | CGRP_NOTIFY_ON_RELEASE, | |
ec64f515 KH |
152 | /* |
153 | * A thread in rmdir() is wating for this cgroup. | |
154 | */ | |
155 | CGRP_WAIT_ON_RMDIR, | |
3116f0e3 PM |
156 | }; |
157 | ||
72a8cb30 BB |
158 | /* which pidlist file are we talking about? */ |
159 | enum cgroup_filetype { | |
160 | CGROUP_FILE_PROCS, | |
161 | CGROUP_FILE_TASKS, | |
162 | }; | |
163 | ||
164 | /* | |
165 | * A pidlist is a list of pids that virtually represents the contents of one | |
166 | * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists, | |
167 | * a pair (one each for procs, tasks) for each pid namespace that's relevant | |
168 | * to the cgroup. | |
169 | */ | |
102a775e | 170 | struct cgroup_pidlist { |
72a8cb30 BB |
171 | /* |
172 | * used to find which pidlist is wanted. doesn't change as long as | |
173 | * this particular list stays in the list. | |
174 | */ | |
175 | struct { enum cgroup_filetype type; struct pid_namespace *ns; } key; | |
102a775e BB |
176 | /* array of xids */ |
177 | pid_t *list; | |
178 | /* how many elements the above list has */ | |
179 | int length; | |
180 | /* how many files are using the current array */ | |
181 | int use_count; | |
72a8cb30 BB |
182 | /* each of these stored in a list by its cgroup */ |
183 | struct list_head links; | |
184 | /* pointer to the cgroup we belong to, for list removal purposes */ | |
185 | struct cgroup *owner; | |
186 | /* protects the other fields */ | |
187 | struct rw_semaphore mutex; | |
102a775e BB |
188 | }; |
189 | ||
ddbcc7e8 PM |
190 | struct cgroup { |
191 | unsigned long flags; /* "unsigned long" so bitops work */ | |
192 | ||
d20a390a PM |
193 | /* |
194 | * count users of this cgroup. >0 means busy, but doesn't | |
195 | * necessarily indicate the number of tasks in the cgroup | |
196 | */ | |
ddbcc7e8 PM |
197 | atomic_t count; |
198 | ||
199 | /* | |
200 | * We link our 'sibling' struct into our parent's 'children'. | |
201 | * Our children link their 'sibling' into our 'children'. | |
202 | */ | |
203 | struct list_head sibling; /* my parent's children */ | |
204 | struct list_head children; /* my children */ | |
205 | ||
d20a390a | 206 | struct cgroup *parent; /* my parent */ |
a47295e6 | 207 | struct dentry *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 PM |
208 | |
209 | /* Private pointers for each registered subsystem */ | |
210 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
211 | ||
212 | struct cgroupfs_root *root; | |
213 | struct cgroup *top_cgroup; | |
817929ec PM |
214 | |
215 | /* | |
216 | * List of cg_cgroup_links pointing at css_sets with | |
217 | * tasks in this cgroup. Protected by css_set_lock | |
218 | */ | |
219 | struct list_head css_sets; | |
81a6a5cd PM |
220 | |
221 | /* | |
222 | * Linked list running through all cgroups that can | |
223 | * potentially be reaped by the release agent. Protected by | |
224 | * release_list_lock | |
225 | */ | |
226 | struct list_head release_list; | |
cc31edce | 227 | |
72a8cb30 BB |
228 | /* |
229 | * list of pidlists, up to two for each namespace (one for procs, one | |
230 | * for tasks); created on demand. | |
231 | */ | |
232 | struct list_head pidlists; | |
233 | struct mutex pidlist_mutex; | |
a47295e6 PM |
234 | |
235 | /* For RCU-protected deletion */ | |
236 | struct rcu_head rcu_head; | |
817929ec PM |
237 | }; |
238 | ||
d20a390a PM |
239 | /* |
240 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
241 | * cgroup_subsys_state objects. This saves space in the task struct |
242 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
243 | * list_add()/del() can bump the reference count on the entire cgroup |
244 | * set for a task. | |
817929ec PM |
245 | */ |
246 | ||
247 | struct css_set { | |
248 | ||
249 | /* Reference count */ | |
146aa1bd | 250 | atomic_t refcount; |
817929ec | 251 | |
472b1053 LZ |
252 | /* |
253 | * List running through all cgroup groups in the same hash | |
254 | * slot. Protected by css_set_lock | |
255 | */ | |
256 | struct hlist_node hlist; | |
257 | ||
817929ec PM |
258 | /* |
259 | * List running through all tasks using this cgroup | |
260 | * group. Protected by css_set_lock | |
261 | */ | |
262 | struct list_head tasks; | |
263 | ||
264 | /* | |
265 | * List of cg_cgroup_link objects on link chains from | |
266 | * cgroups referenced from this css_set. Protected by | |
267 | * css_set_lock | |
268 | */ | |
269 | struct list_head cg_links; | |
270 | ||
271 | /* | |
272 | * Set of subsystem states, one for each subsystem. This array | |
273 | * is immutable after creation apart from the init_css_set | |
274 | * during subsystem registration (at boot time). | |
275 | */ | |
276 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
277 | |
278 | /* For RCU-protected deletion */ | |
279 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
280 | }; |
281 | ||
91796569 PM |
282 | /* |
283 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
284 | * control files | |
285 | */ | |
286 | ||
287 | struct cgroup_map_cb { | |
288 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
289 | void *state; | |
290 | }; | |
291 | ||
d20a390a PM |
292 | /* |
293 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
294 | * |
295 | * When reading/writing to a file: | |
a043e3b2 | 296 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
297 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
298 | */ | |
299 | ||
300 | #define MAX_CFTYPE_NAME 64 | |
301 | struct cftype { | |
d20a390a PM |
302 | /* |
303 | * By convention, the name should begin with the name of the | |
304 | * subsystem, followed by a period | |
305 | */ | |
ddbcc7e8 PM |
306 | char name[MAX_CFTYPE_NAME]; |
307 | int private; | |
099fca32 LZ |
308 | /* |
309 | * If not 0, file mode is set to this value, otherwise it will | |
310 | * be figured out automatically | |
311 | */ | |
312 | mode_t mode; | |
db3b1497 PM |
313 | |
314 | /* | |
315 | * If non-zero, defines the maximum length of string that can | |
316 | * be passed to write_string; defaults to 64 | |
317 | */ | |
318 | size_t max_write_len; | |
319 | ||
ce16b49d PM |
320 | int (*open)(struct inode *inode, struct file *file); |
321 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
322 | struct file *file, | |
323 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 324 | /* |
f4c753b7 | 325 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
326 | * single integer. Use it in place of read() |
327 | */ | |
ce16b49d | 328 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
329 | /* |
330 | * read_s64() is a signed version of read_u64() | |
331 | */ | |
ce16b49d | 332 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
333 | /* |
334 | * read_map() is used for defining a map of key/value | |
335 | * pairs. It should call cb->fill(cb, key, value) for each | |
336 | * entry. The key/value pairs (and their ordering) should not | |
337 | * change between reboots. | |
338 | */ | |
ce16b49d PM |
339 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
340 | struct cgroup_map_cb *cb); | |
29486df3 SH |
341 | /* |
342 | * read_seq_string() is used for outputting a simple sequence | |
343 | * using seqfile. | |
344 | */ | |
ce16b49d PM |
345 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
346 | struct seq_file *m); | |
91796569 | 347 | |
ce16b49d PM |
348 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
349 | struct file *file, | |
350 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
351 | |
352 | /* | |
f4c753b7 | 353 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
354 | * a single integer (as parsed by simple_strtoull) from |
355 | * userspace. Use in place of write(); return 0 or error. | |
356 | */ | |
ce16b49d | 357 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
358 | /* |
359 | * write_s64() is a signed version of write_u64() | |
360 | */ | |
ce16b49d | 361 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 362 | |
db3b1497 PM |
363 | /* |
364 | * write_string() is passed a nul-terminated kernelspace | |
365 | * buffer of maximum length determined by max_write_len. | |
366 | * Returns 0 or -ve error code. | |
367 | */ | |
368 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
369 | const char *buffer); | |
d447ea2f PE |
370 | /* |
371 | * trigger() callback can be used to get some kick from the | |
372 | * userspace, when the actual string written is not important | |
373 | * at all. The private field can be used to determine the | |
374 | * kick type for multiplexing. | |
375 | */ | |
376 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
377 | ||
ce16b49d | 378 | int (*release)(struct inode *inode, struct file *file); |
ddbcc7e8 PM |
379 | }; |
380 | ||
31a7df01 CW |
381 | struct cgroup_scanner { |
382 | struct cgroup *cg; | |
383 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
384 | void (*process_task)(struct task_struct *p, | |
385 | struct cgroup_scanner *scan); | |
386 | struct ptr_heap *heap; | |
bd1a8ab7 | 387 | void *data; |
31a7df01 CW |
388 | }; |
389 | ||
d20a390a PM |
390 | /* |
391 | * Add a new file to the given cgroup directory. Should only be | |
392 | * called by subsystems from within a populate() method | |
393 | */ | |
ffd2d883 | 394 | int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, |
ddbcc7e8 PM |
395 | const struct cftype *cft); |
396 | ||
d20a390a PM |
397 | /* |
398 | * Add a set of new files to the given cgroup directory. Should | |
399 | * only be called by subsystems from within a populate() method | |
400 | */ | |
ffd2d883 | 401 | int cgroup_add_files(struct cgroup *cgrp, |
ddbcc7e8 PM |
402 | struct cgroup_subsys *subsys, |
403 | const struct cftype cft[], | |
404 | int count); | |
405 | ||
ffd2d883 | 406 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 407 | |
ffd2d883 | 408 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 409 | |
ffd2d883 | 410 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 411 | |
313e924c GN |
412 | /* Return true if cgrp is a descendant of the task's cgroup */ |
413 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); | |
ddbcc7e8 | 414 | |
88703267 KH |
415 | /* |
416 | * When the subsys has to access css and may add permanent refcnt to css, | |
417 | * it should take care of racy conditions with rmdir(). Following set of | |
418 | * functions, is for stop/restart rmdir if necessary. | |
419 | * Because these will call css_get/put, "css" should be alive css. | |
420 | * | |
421 | * cgroup_exclude_rmdir(); | |
422 | * ...do some jobs which may access arbitrary empty cgroup | |
423 | * cgroup_release_and_wakeup_rmdir(); | |
424 | * | |
425 | * When someone removes a cgroup while cgroup_exclude_rmdir() holds it, | |
426 | * it sleeps and cgroup_release_and_wakeup_rmdir() will wake him up. | |
427 | */ | |
428 | ||
429 | void cgroup_exclude_rmdir(struct cgroup_subsys_state *css); | |
430 | void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css); | |
431 | ||
21acb9ca TLSC |
432 | /* |
433 | * Control Group subsystem type. | |
434 | * See Documentation/cgroups/cgroups.txt for details | |
435 | */ | |
ddbcc7e8 PM |
436 | |
437 | struct cgroup_subsys { | |
438 | struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, | |
ffd2d883 | 439 | struct cgroup *cgrp); |
ec64f515 | 440 | int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
ffd2d883 | 441 | void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
be367d09 BB |
442 | int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
443 | struct task_struct *tsk, bool threadgroup); | |
2468c723 DN |
444 | void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
445 | struct task_struct *tsk, bool threadgroup); | |
ffd2d883 | 446 | void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
be367d09 BB |
447 | struct cgroup *old_cgrp, struct task_struct *tsk, |
448 | bool threadgroup); | |
ddbcc7e8 PM |
449 | void (*fork)(struct cgroup_subsys *ss, struct task_struct *task); |
450 | void (*exit)(struct cgroup_subsys *ss, struct task_struct *task); | |
451 | int (*populate)(struct cgroup_subsys *ss, | |
ffd2d883 LZ |
452 | struct cgroup *cgrp); |
453 | void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
ddbcc7e8 | 454 | void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
e5991371 | 455 | |
ddbcc7e8 PM |
456 | int subsys_id; |
457 | int active; | |
8bab8dde | 458 | int disabled; |
ddbcc7e8 | 459 | int early_init; |
38460b48 KH |
460 | /* |
461 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
462 | * (not available in early_init time.) | |
463 | */ | |
464 | bool use_id; | |
ddbcc7e8 PM |
465 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
466 | const char *name; | |
467 | ||
999cd8a4 PM |
468 | /* |
469 | * Protects sibling/children links of cgroups in this | |
470 | * hierarchy, plus protects which hierarchy (or none) the | |
471 | * subsystem is a part of (i.e. root/sibling). To avoid | |
472 | * potential deadlocks, the following operations should not be | |
473 | * undertaken while holding any hierarchy_mutex: | |
474 | * | |
475 | * - allocating memory | |
476 | * - initiating hotplug events | |
477 | */ | |
478 | struct mutex hierarchy_mutex; | |
cfebe563 | 479 | struct lock_class_key subsys_key; |
ddbcc7e8 | 480 | |
999cd8a4 PM |
481 | /* |
482 | * Link to parent, and list entry in parent's children. | |
483 | * Protected by this->hierarchy_mutex and cgroup_lock() | |
484 | */ | |
485 | struct cgroupfs_root *root; | |
ddbcc7e8 | 486 | struct list_head sibling; |
38460b48 KH |
487 | /* used when use_id == true */ |
488 | struct idr idr; | |
489 | spinlock_t id_lock; | |
e6a1105b BB |
490 | |
491 | /* should be defined only by modular subsystems */ | |
492 | struct module *module; | |
ddbcc7e8 PM |
493 | }; |
494 | ||
495 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
496 | #include <linux/cgroup_subsys.h> | |
497 | #undef SUBSYS | |
498 | ||
499 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 500 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 501 | { |
ffd2d883 | 502 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
503 | } |
504 | ||
505 | static inline struct cgroup_subsys_state *task_subsys_state( | |
506 | struct task_struct *task, int subsys_id) | |
507 | { | |
d11c563d PM |
508 | return rcu_dereference_check(task->cgroups->subsys[subsys_id], |
509 | rcu_read_lock_held() || | |
510 | cgroup_lock_is_held()); | |
ddbcc7e8 PM |
511 | } |
512 | ||
513 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
514 | int subsys_id) | |
515 | { | |
516 | return task_subsys_state(task, subsys_id)->cgroup; | |
517 | } | |
518 | ||
e885dcde SH |
519 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss, |
520 | char *nodename); | |
697f4161 | 521 | |
817929ec PM |
522 | /* A cgroup_iter should be treated as an opaque object */ |
523 | struct cgroup_iter { | |
524 | struct list_head *cg_link; | |
525 | struct list_head *task; | |
526 | }; | |
527 | ||
d20a390a PM |
528 | /* |
529 | * To iterate across the tasks in a cgroup: | |
817929ec PM |
530 | * |
531 | * 1) call cgroup_iter_start to intialize an iterator | |
532 | * | |
533 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
534 | * returns NULL or until you want to end the iteration | |
535 | * | |
536 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 537 | * |
d20a390a PM |
538 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
539 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
540 | * the test_task() callback, but not while calling the process_task() | |
541 | * callback. | |
817929ec | 542 | */ |
ffd2d883 LZ |
543 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
544 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 545 | struct cgroup_iter *it); |
ffd2d883 | 546 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 547 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 548 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
817929ec | 549 | |
38460b48 KH |
550 | /* |
551 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
552 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
553 | * CSS ID is assigned at cgroup allocation (create) automatically | |
554 | * and removed when subsys calls free_css_id() function. This is because | |
555 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
556 | * | |
557 | * Looking up and scanning function should be called under rcu_read_lock(). | |
558 | * Taking cgroup_mutex()/hierarchy_mutex() is not necessary for following calls. | |
559 | * But the css returned by this routine can be "not populated yet" or "being | |
560 | * destroyed". The caller should check css and cgroup's status. | |
561 | */ | |
562 | ||
563 | /* | |
564 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
565 | * cgroup_subsys_state. | |
566 | */ | |
567 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
568 | ||
569 | /* Find a cgroup_subsys_state which has given ID */ | |
570 | ||
571 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
572 | ||
573 | /* | |
574 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
575 | * Returning a cgroup_subsys_state or NULL. | |
576 | */ | |
577 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
578 | struct cgroup_subsys_state *root, int *foundid); | |
579 | ||
580 | /* Returns true if root is ancestor of cg */ | |
581 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 582 | const struct cgroup_subsys_state *root); |
38460b48 KH |
583 | |
584 | /* Get id and depth of css */ | |
585 | unsigned short css_id(struct cgroup_subsys_state *css); | |
586 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
587 | ||
ddbcc7e8 PM |
588 | #else /* !CONFIG_CGROUPS */ |
589 | ||
590 | static inline int cgroup_init_early(void) { return 0; } | |
591 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
592 | static inline void cgroup_fork(struct task_struct *p) {} |
593 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 594 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 595 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
596 | |
597 | static inline void cgroup_lock(void) {} | |
598 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
599 | static inline int cgroupstats_build(struct cgroupstats *stats, |
600 | struct dentry *dentry) | |
601 | { | |
602 | return -EINVAL; | |
603 | } | |
ddbcc7e8 PM |
604 | |
605 | #endif /* !CONFIG_CGROUPS */ | |
606 | ||
607 | #endif /* _LINUX_CGROUP_H */ |