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