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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> |
48ddbe19 | 19 | #include <linux/workqueue.h> |
ddbcc7e8 PM |
20 | |
21 | #ifdef CONFIG_CGROUPS | |
22 | ||
23 | struct cgroupfs_root; | |
24 | struct cgroup_subsys; | |
25 | struct inode; | |
84eea842 | 26 | struct cgroup; |
38460b48 | 27 | struct css_id; |
ddbcc7e8 PM |
28 | |
29 | extern int cgroup_init_early(void); | |
30 | extern int cgroup_init(void); | |
ddbcc7e8 | 31 | extern void cgroup_lock(void); |
d11c563d | 32 | extern int cgroup_lock_is_held(void); |
84eea842 | 33 | extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
ddbcc7e8 | 34 | extern void cgroup_unlock(void); |
b4f48b63 PM |
35 | extern void cgroup_fork(struct task_struct *p); |
36 | extern void cgroup_fork_callbacks(struct task_struct *p); | |
817929ec | 37 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 38 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
39 | extern int cgroupstats_build(struct cgroupstats *stats, |
40 | struct dentry *dentry); | |
e6a1105b | 41 | extern int cgroup_load_subsys(struct cgroup_subsys *ss); |
cf5d5941 | 42 | extern void cgroup_unload_subsys(struct cgroup_subsys *ss); |
ddbcc7e8 | 43 | |
828c0950 | 44 | extern const struct file_operations proc_cgroup_operations; |
a424316c | 45 | |
aae8aab4 | 46 | /* Define the enumeration of all builtin cgroup subsystems */ |
817929ec PM |
47 | #define SUBSYS(_x) _x ## _subsys_id, |
48 | enum cgroup_subsys_id { | |
49 | #include <linux/cgroup_subsys.h> | |
aae8aab4 | 50 | CGROUP_BUILTIN_SUBSYS_COUNT |
817929ec PM |
51 | }; |
52 | #undef SUBSYS | |
aae8aab4 BB |
53 | /* |
54 | * This define indicates the maximum number of subsystems that can be loaded | |
55 | * at once. We limit to this many since cgroupfs_root has subsys_bits to keep | |
56 | * track of all of them. | |
57 | */ | |
58 | #define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long)) | |
817929ec | 59 | |
ddbcc7e8 PM |
60 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
61 | struct cgroup_subsys_state { | |
d20a390a PM |
62 | /* |
63 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 64 | * for subsystems that want to know about the cgroup |
d20a390a PM |
65 | * hierarchy structure |
66 | */ | |
ddbcc7e8 PM |
67 | struct cgroup *cgroup; |
68 | ||
d20a390a PM |
69 | /* |
70 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 71 | * to be "busy". Should be accessed via css_get(), |
d20a390a PM |
72 | * css_tryget() and and css_put(). |
73 | */ | |
ddbcc7e8 PM |
74 | |
75 | atomic_t refcnt; | |
76 | ||
77 | unsigned long flags; | |
38460b48 | 78 | /* ID for this css, if possible */ |
2c392b8c | 79 | struct css_id __rcu *id; |
48ddbe19 TH |
80 | |
81 | /* Used to put @cgroup->dentry on the last css_put() */ | |
82 | struct work_struct dput_work; | |
ddbcc7e8 PM |
83 | }; |
84 | ||
85 | /* bits in struct cgroup_subsys_state flags field */ | |
86 | enum { | |
87 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
88 | }; | |
89 | ||
d7b9fff7 DN |
90 | /* Caller must verify that the css is not for root cgroup */ |
91 | static inline void __css_get(struct cgroup_subsys_state *css, int count) | |
92 | { | |
93 | atomic_add(count, &css->refcnt); | |
94 | } | |
95 | ||
ddbcc7e8 | 96 | /* |
e7c5ec91 PM |
97 | * Call css_get() to hold a reference on the css; it can be used |
98 | * for a reference obtained via: | |
99 | * - an existing ref-counted reference to the css | |
100 | * - task->cgroups for a locked task | |
ddbcc7e8 PM |
101 | */ |
102 | ||
103 | static inline void css_get(struct cgroup_subsys_state *css) | |
104 | { | |
105 | /* We don't need to reference count the root state */ | |
106 | if (!test_bit(CSS_ROOT, &css->flags)) | |
d7b9fff7 | 107 | __css_get(css, 1); |
ddbcc7e8 | 108 | } |
e7c5ec91 | 109 | |
e7c5ec91 PM |
110 | /* |
111 | * Call css_tryget() to take a reference on a css if your existing | |
112 | * (known-valid) reference isn't already ref-counted. Returns false if | |
113 | * the css has been destroyed. | |
114 | */ | |
115 | ||
28b4c27b | 116 | extern bool __css_tryget(struct cgroup_subsys_state *css); |
e7c5ec91 PM |
117 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
118 | { | |
119 | if (test_bit(CSS_ROOT, &css->flags)) | |
120 | return true; | |
28b4c27b | 121 | return __css_tryget(css); |
e7c5ec91 PM |
122 | } |
123 | ||
ddbcc7e8 PM |
124 | /* |
125 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 126 | * css_get() or css_tryget() |
ddbcc7e8 PM |
127 | */ |
128 | ||
28b4c27b | 129 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
130 | static inline void css_put(struct cgroup_subsys_state *css) |
131 | { | |
132 | if (!test_bit(CSS_ROOT, &css->flags)) | |
28b4c27b | 133 | __css_put(css); |
ddbcc7e8 PM |
134 | } |
135 | ||
3116f0e3 PM |
136 | /* bits in struct cgroup flags field */ |
137 | enum { | |
138 | /* Control Group is dead */ | |
139 | CGRP_REMOVED, | |
d20a390a PM |
140 | /* |
141 | * Control Group has previously had a child cgroup or a task, | |
142 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
143 | */ | |
3116f0e3 PM |
144 | CGRP_RELEASABLE, |
145 | /* Control Group requires release notifications to userspace */ | |
146 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d DL |
147 | /* |
148 | * Clone cgroup values when creating a new child cgroup | |
149 | */ | |
150 | CGRP_CLONE_CHILDREN, | |
3116f0e3 PM |
151 | }; |
152 | ||
ddbcc7e8 PM |
153 | struct cgroup { |
154 | unsigned long flags; /* "unsigned long" so bitops work */ | |
155 | ||
d20a390a PM |
156 | /* |
157 | * count users of this cgroup. >0 means busy, but doesn't | |
158 | * necessarily indicate the number of tasks in the cgroup | |
159 | */ | |
ddbcc7e8 PM |
160 | atomic_t count; |
161 | ||
162 | /* | |
163 | * We link our 'sibling' struct into our parent's 'children'. | |
164 | * Our children link their 'sibling' into our 'children'. | |
165 | */ | |
166 | struct list_head sibling; /* my parent's children */ | |
167 | struct list_head children; /* my children */ | |
05ef1d7c | 168 | struct list_head files; /* my files */ |
ddbcc7e8 | 169 | |
d20a390a | 170 | struct cgroup *parent; /* my parent */ |
2c392b8c | 171 | struct dentry __rcu *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 PM |
172 | |
173 | /* Private pointers for each registered subsystem */ | |
174 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
175 | ||
176 | struct cgroupfs_root *root; | |
177 | struct cgroup *top_cgroup; | |
817929ec PM |
178 | |
179 | /* | |
180 | * List of cg_cgroup_links pointing at css_sets with | |
181 | * tasks in this cgroup. Protected by css_set_lock | |
182 | */ | |
183 | struct list_head css_sets; | |
81a6a5cd | 184 | |
b0ca5a84 | 185 | struct list_head allcg_node; /* cgroupfs_root->allcg_list */ |
8e3f6541 | 186 | struct list_head cft_q_node; /* used during cftype add/rm */ |
b0ca5a84 | 187 | |
81a6a5cd PM |
188 | /* |
189 | * Linked list running through all cgroups that can | |
190 | * potentially be reaped by the release agent. Protected by | |
191 | * release_list_lock | |
192 | */ | |
193 | struct list_head release_list; | |
cc31edce | 194 | |
72a8cb30 BB |
195 | /* |
196 | * list of pidlists, up to two for each namespace (one for procs, one | |
197 | * for tasks); created on demand. | |
198 | */ | |
199 | struct list_head pidlists; | |
200 | struct mutex pidlist_mutex; | |
a47295e6 PM |
201 | |
202 | /* For RCU-protected deletion */ | |
203 | struct rcu_head rcu_head; | |
0dea1168 | 204 | |
25985edc | 205 | /* List of events which userspace want to receive */ |
0dea1168 KS |
206 | struct list_head event_list; |
207 | spinlock_t event_list_lock; | |
817929ec PM |
208 | }; |
209 | ||
d20a390a PM |
210 | /* |
211 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
212 | * cgroup_subsys_state objects. This saves space in the task struct |
213 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
214 | * list_add()/del() can bump the reference count on the entire cgroup |
215 | * set for a task. | |
817929ec PM |
216 | */ |
217 | ||
218 | struct css_set { | |
219 | ||
220 | /* Reference count */ | |
146aa1bd | 221 | atomic_t refcount; |
817929ec | 222 | |
472b1053 LZ |
223 | /* |
224 | * List running through all cgroup groups in the same hash | |
225 | * slot. Protected by css_set_lock | |
226 | */ | |
227 | struct hlist_node hlist; | |
228 | ||
817929ec PM |
229 | /* |
230 | * List running through all tasks using this cgroup | |
231 | * group. Protected by css_set_lock | |
232 | */ | |
233 | struct list_head tasks; | |
234 | ||
235 | /* | |
236 | * List of cg_cgroup_link objects on link chains from | |
237 | * cgroups referenced from this css_set. Protected by | |
238 | * css_set_lock | |
239 | */ | |
240 | struct list_head cg_links; | |
241 | ||
242 | /* | |
243 | * Set of subsystem states, one for each subsystem. This array | |
244 | * is immutable after creation apart from the init_css_set | |
cf5d5941 BB |
245 | * during subsystem registration (at boot time) and modular subsystem |
246 | * loading/unloading. | |
817929ec PM |
247 | */ |
248 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
249 | |
250 | /* For RCU-protected deletion */ | |
251 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
252 | }; |
253 | ||
91796569 PM |
254 | /* |
255 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
256 | * control files | |
257 | */ | |
258 | ||
259 | struct cgroup_map_cb { | |
260 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
261 | void *state; | |
262 | }; | |
263 | ||
d20a390a PM |
264 | /* |
265 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
266 | * |
267 | * When reading/writing to a file: | |
a043e3b2 | 268 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
269 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
270 | */ | |
271 | ||
8e3f6541 TH |
272 | /* cftype->flags */ |
273 | #define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */ | |
274 | #define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create onp root cg */ | |
275 | ||
276 | #define MAX_CFTYPE_NAME 64 | |
277 | ||
ddbcc7e8 | 278 | struct cftype { |
d20a390a PM |
279 | /* |
280 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
281 | * subsystem, followed by a period. Zero length string indicates |
282 | * end of cftype array. | |
d20a390a | 283 | */ |
ddbcc7e8 PM |
284 | char name[MAX_CFTYPE_NAME]; |
285 | int private; | |
099fca32 LZ |
286 | /* |
287 | * If not 0, file mode is set to this value, otherwise it will | |
288 | * be figured out automatically | |
289 | */ | |
a5e7ed32 | 290 | umode_t mode; |
db3b1497 PM |
291 | |
292 | /* | |
293 | * If non-zero, defines the maximum length of string that can | |
294 | * be passed to write_string; defaults to 64 | |
295 | */ | |
296 | size_t max_write_len; | |
297 | ||
8e3f6541 TH |
298 | /* CFTYPE_* flags */ |
299 | unsigned int flags; | |
300 | ||
ce16b49d PM |
301 | int (*open)(struct inode *inode, struct file *file); |
302 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
303 | struct file *file, | |
304 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 305 | /* |
f4c753b7 | 306 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
307 | * single integer. Use it in place of read() |
308 | */ | |
ce16b49d | 309 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
310 | /* |
311 | * read_s64() is a signed version of read_u64() | |
312 | */ | |
ce16b49d | 313 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
314 | /* |
315 | * read_map() is used for defining a map of key/value | |
316 | * pairs. It should call cb->fill(cb, key, value) for each | |
317 | * entry. The key/value pairs (and their ordering) should not | |
318 | * change between reboots. | |
319 | */ | |
ce16b49d PM |
320 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
321 | struct cgroup_map_cb *cb); | |
29486df3 SH |
322 | /* |
323 | * read_seq_string() is used for outputting a simple sequence | |
324 | * using seqfile. | |
325 | */ | |
ce16b49d PM |
326 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
327 | struct seq_file *m); | |
91796569 | 328 | |
ce16b49d PM |
329 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
330 | struct file *file, | |
331 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
332 | |
333 | /* | |
f4c753b7 | 334 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
335 | * a single integer (as parsed by simple_strtoull) from |
336 | * userspace. Use in place of write(); return 0 or error. | |
337 | */ | |
ce16b49d | 338 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
339 | /* |
340 | * write_s64() is a signed version of write_u64() | |
341 | */ | |
ce16b49d | 342 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 343 | |
db3b1497 PM |
344 | /* |
345 | * write_string() is passed a nul-terminated kernelspace | |
346 | * buffer of maximum length determined by max_write_len. | |
347 | * Returns 0 or -ve error code. | |
348 | */ | |
349 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
350 | const char *buffer); | |
d447ea2f PE |
351 | /* |
352 | * trigger() callback can be used to get some kick from the | |
353 | * userspace, when the actual string written is not important | |
354 | * at all. The private field can be used to determine the | |
355 | * kick type for multiplexing. | |
356 | */ | |
357 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
358 | ||
ce16b49d | 359 | int (*release)(struct inode *inode, struct file *file); |
0dea1168 KS |
360 | |
361 | /* | |
362 | * register_event() callback will be used to add new userspace | |
363 | * waiter for changes related to the cftype. Implement it if | |
364 | * you want to provide this functionality. Use eventfd_signal() | |
365 | * on eventfd to send notification to userspace. | |
366 | */ | |
367 | int (*register_event)(struct cgroup *cgrp, struct cftype *cft, | |
368 | struct eventfd_ctx *eventfd, const char *args); | |
369 | /* | |
370 | * unregister_event() callback will be called when userspace | |
371 | * closes the eventfd or on cgroup removing. | |
372 | * This callback must be implemented, if you want provide | |
373 | * notification functionality. | |
0dea1168 | 374 | */ |
907860ed | 375 | void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
0dea1168 | 376 | struct eventfd_ctx *eventfd); |
ddbcc7e8 PM |
377 | }; |
378 | ||
8e3f6541 TH |
379 | /* |
380 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
381 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
382 | * terminated by zero length name. | |
383 | */ | |
384 | struct cftype_set { | |
385 | struct list_head node; /* chained at subsys->cftsets */ | |
386 | const struct cftype *cfts; | |
387 | }; | |
388 | ||
31a7df01 CW |
389 | struct cgroup_scanner { |
390 | struct cgroup *cg; | |
391 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
392 | void (*process_task)(struct task_struct *p, | |
393 | struct cgroup_scanner *scan); | |
394 | struct ptr_heap *heap; | |
bd1a8ab7 | 395 | void *data; |
31a7df01 CW |
396 | }; |
397 | ||
8e3f6541 | 398 | int cgroup_add_cftypes(struct cgroup_subsys *ss, const struct cftype *cfts); |
79578621 | 399 | int cgroup_rm_cftypes(struct cgroup_subsys *ss, const struct cftype *cfts); |
8e3f6541 | 400 | |
ffd2d883 | 401 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 402 | |
ffd2d883 | 403 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 404 | |
ffd2d883 | 405 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 406 | |
313e924c GN |
407 | /* Return true if cgrp is a descendant of the task's cgroup */ |
408 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); | |
ddbcc7e8 | 409 | |
2f7ee569 TH |
410 | /* |
411 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
412 | * methods. | |
413 | */ | |
414 | struct cgroup_taskset; | |
415 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
416 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
417 | struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset); | |
418 | int cgroup_taskset_size(struct cgroup_taskset *tset); | |
419 | ||
420 | /** | |
421 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
422 | * @task: the loop cursor | |
423 | * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all | |
424 | * @tset: taskset to iterate | |
425 | */ | |
426 | #define cgroup_taskset_for_each(task, skip_cgrp, tset) \ | |
427 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
428 | (task) = cgroup_taskset_next((tset))) \ | |
429 | if (!(skip_cgrp) || \ | |
430 | cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp)) | |
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 { | |
761b3ef5 LZ |
438 | struct cgroup_subsys_state *(*create)(struct cgroup *cgrp); |
439 | int (*pre_destroy)(struct cgroup *cgrp); | |
440 | void (*destroy)(struct cgroup *cgrp); | |
441 | int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
442 | void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
443 | void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
444 | void (*fork)(struct task_struct *task); | |
445 | void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp, | |
446 | struct task_struct *task); | |
761b3ef5 LZ |
447 | void (*post_clone)(struct cgroup *cgrp); |
448 | void (*bind)(struct cgroup *root); | |
e5991371 | 449 | |
ddbcc7e8 PM |
450 | int subsys_id; |
451 | int active; | |
8bab8dde | 452 | int disabled; |
ddbcc7e8 | 453 | int early_init; |
38460b48 KH |
454 | /* |
455 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
456 | * (not available in early_init time.) | |
457 | */ | |
458 | bool use_id; | |
48ddbe19 | 459 | |
ddbcc7e8 PM |
460 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
461 | const char *name; | |
462 | ||
999cd8a4 PM |
463 | /* |
464 | * Link to parent, and list entry in parent's children. | |
6be96a5c | 465 | * Protected by cgroup_lock() |
999cd8a4 PM |
466 | */ |
467 | struct cgroupfs_root *root; | |
ddbcc7e8 | 468 | struct list_head sibling; |
38460b48 KH |
469 | /* used when use_id == true */ |
470 | struct idr idr; | |
42aee6c4 | 471 | spinlock_t id_lock; |
e6a1105b | 472 | |
8e3f6541 TH |
473 | /* list of cftype_sets */ |
474 | struct list_head cftsets; | |
475 | ||
476 | /* base cftypes, automatically [de]registered with subsys itself */ | |
477 | struct cftype *base_cftypes; | |
478 | struct cftype_set base_cftset; | |
479 | ||
e6a1105b BB |
480 | /* should be defined only by modular subsystems */ |
481 | struct module *module; | |
ddbcc7e8 PM |
482 | }; |
483 | ||
484 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
485 | #include <linux/cgroup_subsys.h> | |
486 | #undef SUBSYS | |
487 | ||
488 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 489 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 490 | { |
ffd2d883 | 491 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
492 | } |
493 | ||
dc61b1d6 PZ |
494 | /* |
495 | * function to get the cgroup_subsys_state which allows for extra | |
496 | * rcu_dereference_check() conditions, such as locks used during the | |
497 | * cgroup_subsys::attach() methods. | |
498 | */ | |
499 | #define task_subsys_state_check(task, subsys_id, __c) \ | |
500 | rcu_dereference_check(task->cgroups->subsys[subsys_id], \ | |
dc61b1d6 PZ |
501 | lockdep_is_held(&task->alloc_lock) || \ |
502 | cgroup_lock_is_held() || (__c)) | |
503 | ||
504 | static inline struct cgroup_subsys_state * | |
505 | task_subsys_state(struct task_struct *task, int subsys_id) | |
ddbcc7e8 | 506 | { |
dc61b1d6 | 507 | return task_subsys_state_check(task, subsys_id, false); |
ddbcc7e8 PM |
508 | } |
509 | ||
510 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
511 | int subsys_id) | |
512 | { | |
513 | return task_subsys_state(task, subsys_id)->cgroup; | |
514 | } | |
515 | ||
817929ec PM |
516 | /* A cgroup_iter should be treated as an opaque object */ |
517 | struct cgroup_iter { | |
518 | struct list_head *cg_link; | |
519 | struct list_head *task; | |
520 | }; | |
521 | ||
d20a390a PM |
522 | /* |
523 | * To iterate across the tasks in a cgroup: | |
817929ec | 524 | * |
b595076a | 525 | * 1) call cgroup_iter_start to initialize an iterator |
817929ec PM |
526 | * |
527 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
528 | * returns NULL or until you want to end the iteration | |
529 | * | |
530 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 531 | * |
d20a390a PM |
532 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
533 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
534 | * the test_task() callback, but not while calling the process_task() | |
535 | * callback. | |
817929ec | 536 | */ |
ffd2d883 LZ |
537 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
538 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 539 | struct cgroup_iter *it); |
ffd2d883 | 540 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 541 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 542 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
31583bb0 MT |
543 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
544 | ||
38460b48 KH |
545 | /* |
546 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
547 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
548 | * CSS ID is assigned at cgroup allocation (create) automatically | |
549 | * and removed when subsys calls free_css_id() function. This is because | |
550 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
551 | * | |
552 | * Looking up and scanning function should be called under rcu_read_lock(). | |
6be96a5c | 553 | * Taking cgroup_mutex is not necessary for following calls. |
38460b48 KH |
554 | * But the css returned by this routine can be "not populated yet" or "being |
555 | * destroyed". The caller should check css and cgroup's status. | |
556 | */ | |
557 | ||
558 | /* | |
559 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
560 | * cgroup_subsys_state. | |
561 | */ | |
562 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
563 | ||
564 | /* Find a cgroup_subsys_state which has given ID */ | |
565 | ||
566 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
567 | ||
568 | /* | |
569 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
570 | * Returning a cgroup_subsys_state or NULL. | |
571 | */ | |
572 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
573 | struct cgroup_subsys_state *root, int *foundid); | |
574 | ||
575 | /* Returns true if root is ancestor of cg */ | |
576 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 577 | const struct cgroup_subsys_state *root); |
38460b48 KH |
578 | |
579 | /* Get id and depth of css */ | |
580 | unsigned short css_id(struct cgroup_subsys_state *css); | |
581 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
e5d1367f | 582 | struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); |
38460b48 | 583 | |
ddbcc7e8 PM |
584 | #else /* !CONFIG_CGROUPS */ |
585 | ||
586 | static inline int cgroup_init_early(void) { return 0; } | |
587 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
588 | static inline void cgroup_fork(struct task_struct *p) {} |
589 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 590 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 591 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
592 | |
593 | static inline void cgroup_lock(void) {} | |
594 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
595 | static inline int cgroupstats_build(struct cgroupstats *stats, |
596 | struct dentry *dentry) | |
597 | { | |
598 | return -EINVAL; | |
599 | } | |
ddbcc7e8 | 600 | |
d7926ee3 | 601 | /* No cgroups - nothing to do */ |
31583bb0 MT |
602 | static inline int cgroup_attach_task_all(struct task_struct *from, |
603 | struct task_struct *t) | |
604 | { | |
605 | return 0; | |
606 | } | |
d7926ee3 | 607 | |
ddbcc7e8 PM |
608 | #endif /* !CONFIG_CGROUPS */ |
609 | ||
610 | #endif /* _LINUX_CGROUP_H */ |