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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> |
03b1cde6 | 20 | #include <linux/xattr.h> |
ddbcc7e8 PM |
21 | |
22 | #ifdef CONFIG_CGROUPS | |
23 | ||
24 | struct cgroupfs_root; | |
25 | struct cgroup_subsys; | |
26 | struct inode; | |
84eea842 | 27 | struct cgroup; |
38460b48 | 28 | struct css_id; |
ddbcc7e8 PM |
29 | |
30 | extern int cgroup_init_early(void); | |
31 | extern int cgroup_init(void); | |
ddbcc7e8 | 32 | extern void cgroup_lock(void); |
d11c563d | 33 | extern int cgroup_lock_is_held(void); |
84eea842 | 34 | extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
ddbcc7e8 | 35 | extern void cgroup_unlock(void); |
b4f48b63 | 36 | extern void cgroup_fork(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 | 47 | #define SUBSYS(_x) _x ## _subsys_id, |
8a8e04df | 48 | #define IS_SUBSYS_ENABLED(option) IS_ENABLED(option) |
817929ec PM |
49 | enum cgroup_subsys_id { |
50 | #include <linux/cgroup_subsys.h> | |
a6f00298 | 51 | CGROUP_SUBSYS_COUNT, |
817929ec | 52 | }; |
5fc0b025 | 53 | #undef IS_SUBSYS_ENABLED |
817929ec PM |
54 | #undef SUBSYS |
55 | ||
ddbcc7e8 PM |
56 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
57 | struct cgroup_subsys_state { | |
d20a390a PM |
58 | /* |
59 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 60 | * for subsystems that want to know about the cgroup |
d20a390a PM |
61 | * hierarchy structure |
62 | */ | |
ddbcc7e8 PM |
63 | struct cgroup *cgroup; |
64 | ||
d20a390a PM |
65 | /* |
66 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 67 | * to be "busy". Should be accessed via css_get(), |
d20a390a PM |
68 | * css_tryget() and and css_put(). |
69 | */ | |
ddbcc7e8 PM |
70 | |
71 | atomic_t refcnt; | |
72 | ||
73 | unsigned long flags; | |
38460b48 | 74 | /* ID for this css, if possible */ |
2c392b8c | 75 | struct css_id __rcu *id; |
48ddbe19 TH |
76 | |
77 | /* Used to put @cgroup->dentry on the last css_put() */ | |
78 | struct work_struct dput_work; | |
ddbcc7e8 PM |
79 | }; |
80 | ||
81 | /* bits in struct cgroup_subsys_state flags field */ | |
82 | enum { | |
83 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
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 | 105 | |
e7c5ec91 PM |
106 | /* |
107 | * Call css_tryget() to take a reference on a css if your existing | |
108 | * (known-valid) reference isn't already ref-counted. Returns false if | |
109 | * the css has been destroyed. | |
110 | */ | |
111 | ||
28b4c27b | 112 | extern bool __css_tryget(struct cgroup_subsys_state *css); |
e7c5ec91 PM |
113 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
114 | { | |
115 | if (test_bit(CSS_ROOT, &css->flags)) | |
116 | return true; | |
28b4c27b | 117 | return __css_tryget(css); |
e7c5ec91 PM |
118 | } |
119 | ||
ddbcc7e8 PM |
120 | /* |
121 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 122 | * css_get() or css_tryget() |
ddbcc7e8 PM |
123 | */ |
124 | ||
28b4c27b | 125 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
126 | static inline void css_put(struct cgroup_subsys_state *css) |
127 | { | |
128 | if (!test_bit(CSS_ROOT, &css->flags)) | |
28b4c27b | 129 | __css_put(css); |
ddbcc7e8 PM |
130 | } |
131 | ||
3116f0e3 PM |
132 | /* bits in struct cgroup flags field */ |
133 | enum { | |
134 | /* Control Group is dead */ | |
135 | CGRP_REMOVED, | |
d20a390a PM |
136 | /* |
137 | * Control Group has previously had a child cgroup or a task, | |
138 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
139 | */ | |
3116f0e3 PM |
140 | CGRP_RELEASABLE, |
141 | /* Control Group requires release notifications to userspace */ | |
142 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d DL |
143 | /* |
144 | * Clone cgroup values when creating a new child cgroup | |
145 | */ | |
146 | CGRP_CLONE_CHILDREN, | |
3116f0e3 PM |
147 | }; |
148 | ||
ddbcc7e8 PM |
149 | struct cgroup { |
150 | unsigned long flags; /* "unsigned long" so bitops work */ | |
151 | ||
d20a390a PM |
152 | /* |
153 | * count users of this cgroup. >0 means busy, but doesn't | |
154 | * necessarily indicate the number of tasks in the cgroup | |
155 | */ | |
ddbcc7e8 PM |
156 | atomic_t count; |
157 | ||
158 | /* | |
159 | * We link our 'sibling' struct into our parent's 'children'. | |
160 | * Our children link their 'sibling' into our 'children'. | |
161 | */ | |
162 | struct list_head sibling; /* my parent's children */ | |
163 | struct list_head children; /* my children */ | |
05ef1d7c | 164 | struct list_head files; /* my files */ |
ddbcc7e8 | 165 | |
d20a390a | 166 | struct cgroup *parent; /* my parent */ |
2c392b8c | 167 | struct dentry __rcu *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 PM |
168 | |
169 | /* Private pointers for each registered subsystem */ | |
170 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
171 | ||
172 | struct cgroupfs_root *root; | |
173 | struct cgroup *top_cgroup; | |
817929ec PM |
174 | |
175 | /* | |
176 | * List of cg_cgroup_links pointing at css_sets with | |
177 | * tasks in this cgroup. Protected by css_set_lock | |
178 | */ | |
179 | struct list_head css_sets; | |
81a6a5cd | 180 | |
b0ca5a84 | 181 | struct list_head allcg_node; /* cgroupfs_root->allcg_list */ |
8e3f6541 | 182 | struct list_head cft_q_node; /* used during cftype add/rm */ |
b0ca5a84 | 183 | |
81a6a5cd PM |
184 | /* |
185 | * Linked list running through all cgroups that can | |
186 | * potentially be reaped by the release agent. Protected by | |
187 | * release_list_lock | |
188 | */ | |
189 | struct list_head release_list; | |
cc31edce | 190 | |
72a8cb30 BB |
191 | /* |
192 | * list of pidlists, up to two for each namespace (one for procs, one | |
193 | * for tasks); created on demand. | |
194 | */ | |
195 | struct list_head pidlists; | |
196 | struct mutex pidlist_mutex; | |
a47295e6 PM |
197 | |
198 | /* For RCU-protected deletion */ | |
199 | struct rcu_head rcu_head; | |
0dea1168 | 200 | |
25985edc | 201 | /* List of events which userspace want to receive */ |
0dea1168 KS |
202 | struct list_head event_list; |
203 | spinlock_t event_list_lock; | |
03b1cde6 AR |
204 | |
205 | /* directory xattrs */ | |
206 | struct simple_xattrs xattrs; | |
817929ec PM |
207 | }; |
208 | ||
d20a390a PM |
209 | /* |
210 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
211 | * cgroup_subsys_state objects. This saves space in the task struct |
212 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
213 | * list_add()/del() can bump the reference count on the entire cgroup |
214 | * set for a task. | |
817929ec PM |
215 | */ |
216 | ||
217 | struct css_set { | |
218 | ||
219 | /* Reference count */ | |
146aa1bd | 220 | atomic_t refcount; |
817929ec | 221 | |
472b1053 LZ |
222 | /* |
223 | * List running through all cgroup groups in the same hash | |
224 | * slot. Protected by css_set_lock | |
225 | */ | |
226 | struct hlist_node hlist; | |
227 | ||
817929ec PM |
228 | /* |
229 | * List running through all tasks using this cgroup | |
230 | * group. Protected by css_set_lock | |
231 | */ | |
232 | struct list_head tasks; | |
233 | ||
234 | /* | |
235 | * List of cg_cgroup_link objects on link chains from | |
236 | * cgroups referenced from this css_set. Protected by | |
237 | * css_set_lock | |
238 | */ | |
239 | struct list_head cg_links; | |
240 | ||
241 | /* | |
242 | * Set of subsystem states, one for each subsystem. This array | |
243 | * is immutable after creation apart from the init_css_set | |
cf5d5941 BB |
244 | * during subsystem registration (at boot time) and modular subsystem |
245 | * loading/unloading. | |
817929ec PM |
246 | */ |
247 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
248 | |
249 | /* For RCU-protected deletion */ | |
250 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
251 | }; |
252 | ||
91796569 PM |
253 | /* |
254 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
255 | * control files | |
256 | */ | |
257 | ||
258 | struct cgroup_map_cb { | |
259 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
260 | void *state; | |
261 | }; | |
262 | ||
d20a390a PM |
263 | /* |
264 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
265 | * |
266 | * When reading/writing to a file: | |
a043e3b2 | 267 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
268 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
269 | */ | |
270 | ||
8e3f6541 TH |
271 | /* cftype->flags */ |
272 | #define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */ | |
273 | #define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create onp root cg */ | |
274 | ||
275 | #define MAX_CFTYPE_NAME 64 | |
276 | ||
ddbcc7e8 | 277 | struct cftype { |
d20a390a PM |
278 | /* |
279 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
280 | * subsystem, followed by a period. Zero length string indicates |
281 | * end of cftype array. | |
d20a390a | 282 | */ |
ddbcc7e8 PM |
283 | char name[MAX_CFTYPE_NAME]; |
284 | int private; | |
099fca32 LZ |
285 | /* |
286 | * If not 0, file mode is set to this value, otherwise it will | |
287 | * be figured out automatically | |
288 | */ | |
a5e7ed32 | 289 | umode_t mode; |
db3b1497 PM |
290 | |
291 | /* | |
292 | * If non-zero, defines the maximum length of string that can | |
293 | * be passed to write_string; defaults to 64 | |
294 | */ | |
295 | size_t max_write_len; | |
296 | ||
8e3f6541 TH |
297 | /* CFTYPE_* flags */ |
298 | unsigned int flags; | |
299 | ||
03b1cde6 AR |
300 | /* file xattrs */ |
301 | struct simple_xattrs xattrs; | |
302 | ||
ce16b49d PM |
303 | int (*open)(struct inode *inode, struct file *file); |
304 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
305 | struct file *file, | |
306 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 307 | /* |
f4c753b7 | 308 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
309 | * single integer. Use it in place of read() |
310 | */ | |
ce16b49d | 311 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
312 | /* |
313 | * read_s64() is a signed version of read_u64() | |
314 | */ | |
ce16b49d | 315 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
316 | /* |
317 | * read_map() is used for defining a map of key/value | |
318 | * pairs. It should call cb->fill(cb, key, value) for each | |
319 | * entry. The key/value pairs (and their ordering) should not | |
320 | * change between reboots. | |
321 | */ | |
ce16b49d PM |
322 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
323 | struct cgroup_map_cb *cb); | |
29486df3 SH |
324 | /* |
325 | * read_seq_string() is used for outputting a simple sequence | |
326 | * using seqfile. | |
327 | */ | |
ce16b49d PM |
328 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
329 | struct seq_file *m); | |
91796569 | 330 | |
ce16b49d PM |
331 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
332 | struct file *file, | |
333 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
334 | |
335 | /* | |
f4c753b7 | 336 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
337 | * a single integer (as parsed by simple_strtoull) from |
338 | * userspace. Use in place of write(); return 0 or error. | |
339 | */ | |
ce16b49d | 340 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
341 | /* |
342 | * write_s64() is a signed version of write_u64() | |
343 | */ | |
ce16b49d | 344 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 345 | |
db3b1497 PM |
346 | /* |
347 | * write_string() is passed a nul-terminated kernelspace | |
348 | * buffer of maximum length determined by max_write_len. | |
349 | * Returns 0 or -ve error code. | |
350 | */ | |
351 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
352 | const char *buffer); | |
d447ea2f PE |
353 | /* |
354 | * trigger() callback can be used to get some kick from the | |
355 | * userspace, when the actual string written is not important | |
356 | * at all. The private field can be used to determine the | |
357 | * kick type for multiplexing. | |
358 | */ | |
359 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
360 | ||
ce16b49d | 361 | int (*release)(struct inode *inode, struct file *file); |
0dea1168 KS |
362 | |
363 | /* | |
364 | * register_event() callback will be used to add new userspace | |
365 | * waiter for changes related to the cftype. Implement it if | |
366 | * you want to provide this functionality. Use eventfd_signal() | |
367 | * on eventfd to send notification to userspace. | |
368 | */ | |
369 | int (*register_event)(struct cgroup *cgrp, struct cftype *cft, | |
370 | struct eventfd_ctx *eventfd, const char *args); | |
371 | /* | |
372 | * unregister_event() callback will be called when userspace | |
373 | * closes the eventfd or on cgroup removing. | |
374 | * This callback must be implemented, if you want provide | |
375 | * notification functionality. | |
0dea1168 | 376 | */ |
907860ed | 377 | void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
0dea1168 | 378 | struct eventfd_ctx *eventfd); |
ddbcc7e8 PM |
379 | }; |
380 | ||
8e3f6541 TH |
381 | /* |
382 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
383 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
384 | * terminated by zero length name. | |
385 | */ | |
386 | struct cftype_set { | |
387 | struct list_head node; /* chained at subsys->cftsets */ | |
03b1cde6 | 388 | struct cftype *cfts; |
8e3f6541 TH |
389 | }; |
390 | ||
31a7df01 CW |
391 | struct cgroup_scanner { |
392 | struct cgroup *cg; | |
393 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
394 | void (*process_task)(struct task_struct *p, | |
395 | struct cgroup_scanner *scan); | |
396 | struct ptr_heap *heap; | |
bd1a8ab7 | 397 | void *data; |
31a7df01 CW |
398 | }; |
399 | ||
03b1cde6 AR |
400 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
401 | int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
8e3f6541 | 402 | |
ffd2d883 | 403 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 404 | |
ffd2d883 | 405 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 406 | |
ffd2d883 | 407 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 408 | |
313e924c GN |
409 | /* Return true if cgrp is a descendant of the task's cgroup */ |
410 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); | |
ddbcc7e8 | 411 | |
2f7ee569 TH |
412 | /* |
413 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
414 | * methods. | |
415 | */ | |
416 | struct cgroup_taskset; | |
417 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
418 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
419 | struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset); | |
420 | int cgroup_taskset_size(struct cgroup_taskset *tset); | |
421 | ||
422 | /** | |
423 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
424 | * @task: the loop cursor | |
425 | * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all | |
426 | * @tset: taskset to iterate | |
427 | */ | |
428 | #define cgroup_taskset_for_each(task, skip_cgrp, tset) \ | |
429 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
430 | (task) = cgroup_taskset_next((tset))) \ | |
431 | if (!(skip_cgrp) || \ | |
432 | cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp)) | |
433 | ||
21acb9ca TLSC |
434 | /* |
435 | * Control Group subsystem type. | |
436 | * See Documentation/cgroups/cgroups.txt for details | |
437 | */ | |
ddbcc7e8 PM |
438 | |
439 | struct cgroup_subsys { | |
761b3ef5 | 440 | struct cgroup_subsys_state *(*create)(struct cgroup *cgrp); |
a8638030 | 441 | void (*post_create)(struct cgroup *cgrp); |
bcf6de1b | 442 | void (*pre_destroy)(struct cgroup *cgrp); |
761b3ef5 LZ |
443 | void (*destroy)(struct cgroup *cgrp); |
444 | int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
445 | void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
446 | void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
447 | void (*fork)(struct task_struct *task); | |
448 | void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp, | |
449 | struct task_struct *task); | |
761b3ef5 LZ |
450 | void (*post_clone)(struct cgroup *cgrp); |
451 | void (*bind)(struct cgroup *root); | |
e5991371 | 452 | |
ddbcc7e8 PM |
453 | int subsys_id; |
454 | int active; | |
8bab8dde | 455 | int disabled; |
ddbcc7e8 | 456 | int early_init; |
38460b48 KH |
457 | /* |
458 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
459 | * (not available in early_init time.) | |
460 | */ | |
461 | bool use_id; | |
48ddbe19 | 462 | |
8c7f6edb TH |
463 | /* |
464 | * If %false, this subsystem is properly hierarchical - | |
465 | * configuration, resource accounting and restriction on a parent | |
466 | * cgroup cover those of its children. If %true, hierarchy support | |
467 | * is broken in some ways - some subsystems ignore hierarchy | |
468 | * completely while others are only implemented half-way. | |
469 | * | |
470 | * It's now disallowed to create nested cgroups if the subsystem is | |
471 | * broken and cgroup core will emit a warning message on such | |
472 | * cases. Eventually, all subsystems will be made properly | |
473 | * hierarchical and this will go away. | |
474 | */ | |
475 | bool broken_hierarchy; | |
476 | bool warned_broken_hierarchy; | |
477 | ||
ddbcc7e8 PM |
478 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
479 | const char *name; | |
480 | ||
999cd8a4 PM |
481 | /* |
482 | * Link to parent, and list entry in parent's children. | |
6be96a5c | 483 | * Protected by cgroup_lock() |
999cd8a4 PM |
484 | */ |
485 | struct cgroupfs_root *root; | |
ddbcc7e8 | 486 | struct list_head sibling; |
38460b48 KH |
487 | /* used when use_id == true */ |
488 | struct idr idr; | |
42aee6c4 | 489 | spinlock_t id_lock; |
e6a1105b | 490 | |
8e3f6541 TH |
491 | /* list of cftype_sets */ |
492 | struct list_head cftsets; | |
493 | ||
494 | /* base cftypes, automatically [de]registered with subsys itself */ | |
495 | struct cftype *base_cftypes; | |
496 | struct cftype_set base_cftset; | |
497 | ||
e6a1105b BB |
498 | /* should be defined only by modular subsystems */ |
499 | struct module *module; | |
ddbcc7e8 PM |
500 | }; |
501 | ||
502 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
5fc0b025 | 503 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
ddbcc7e8 | 504 | #include <linux/cgroup_subsys.h> |
5fc0b025 | 505 | #undef IS_SUBSYS_ENABLED |
ddbcc7e8 PM |
506 | #undef SUBSYS |
507 | ||
508 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 509 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 510 | { |
ffd2d883 | 511 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
512 | } |
513 | ||
dc61b1d6 PZ |
514 | /* |
515 | * function to get the cgroup_subsys_state which allows for extra | |
516 | * rcu_dereference_check() conditions, such as locks used during the | |
517 | * cgroup_subsys::attach() methods. | |
518 | */ | |
519 | #define task_subsys_state_check(task, subsys_id, __c) \ | |
520 | rcu_dereference_check(task->cgroups->subsys[subsys_id], \ | |
dc61b1d6 PZ |
521 | lockdep_is_held(&task->alloc_lock) || \ |
522 | cgroup_lock_is_held() || (__c)) | |
523 | ||
524 | static inline struct cgroup_subsys_state * | |
525 | task_subsys_state(struct task_struct *task, int subsys_id) | |
ddbcc7e8 | 526 | { |
dc61b1d6 | 527 | return task_subsys_state_check(task, subsys_id, false); |
ddbcc7e8 PM |
528 | } |
529 | ||
530 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
531 | int subsys_id) | |
532 | { | |
533 | return task_subsys_state(task, subsys_id)->cgroup; | |
534 | } | |
535 | ||
817929ec PM |
536 | /* A cgroup_iter should be treated as an opaque object */ |
537 | struct cgroup_iter { | |
538 | struct list_head *cg_link; | |
539 | struct list_head *task; | |
540 | }; | |
541 | ||
d20a390a PM |
542 | /* |
543 | * To iterate across the tasks in a cgroup: | |
817929ec | 544 | * |
b595076a | 545 | * 1) call cgroup_iter_start to initialize an iterator |
817929ec PM |
546 | * |
547 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
548 | * returns NULL or until you want to end the iteration | |
549 | * | |
550 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 551 | * |
d20a390a PM |
552 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
553 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
554 | * the test_task() callback, but not while calling the process_task() | |
555 | * callback. | |
817929ec | 556 | */ |
ffd2d883 LZ |
557 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
558 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 559 | struct cgroup_iter *it); |
ffd2d883 | 560 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 561 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 562 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
31583bb0 MT |
563 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
564 | ||
38460b48 KH |
565 | /* |
566 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
567 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
568 | * CSS ID is assigned at cgroup allocation (create) automatically | |
569 | * and removed when subsys calls free_css_id() function. This is because | |
570 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
571 | * | |
572 | * Looking up and scanning function should be called under rcu_read_lock(). | |
6be96a5c | 573 | * Taking cgroup_mutex is not necessary for following calls. |
38460b48 KH |
574 | * But the css returned by this routine can be "not populated yet" or "being |
575 | * destroyed". The caller should check css and cgroup's status. | |
576 | */ | |
577 | ||
578 | /* | |
579 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
580 | * cgroup_subsys_state. | |
581 | */ | |
582 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
583 | ||
584 | /* Find a cgroup_subsys_state which has given ID */ | |
585 | ||
586 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
587 | ||
588 | /* | |
589 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
590 | * Returning a cgroup_subsys_state or NULL. | |
591 | */ | |
592 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
593 | struct cgroup_subsys_state *root, int *foundid); | |
594 | ||
595 | /* Returns true if root is ancestor of cg */ | |
596 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 597 | const struct cgroup_subsys_state *root); |
38460b48 KH |
598 | |
599 | /* Get id and depth of css */ | |
600 | unsigned short css_id(struct cgroup_subsys_state *css); | |
601 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
e5d1367f | 602 | struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); |
38460b48 | 603 | |
ddbcc7e8 PM |
604 | #else /* !CONFIG_CGROUPS */ |
605 | ||
606 | static inline int cgroup_init_early(void) { return 0; } | |
607 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
608 | static inline void cgroup_fork(struct task_struct *p) {} |
609 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 610 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 611 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
612 | |
613 | static inline void cgroup_lock(void) {} | |
614 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
615 | static inline int cgroupstats_build(struct cgroupstats *stats, |
616 | struct dentry *dentry) | |
617 | { | |
618 | return -EINVAL; | |
619 | } | |
ddbcc7e8 | 620 | |
d7926ee3 | 621 | /* No cgroups - nothing to do */ |
31583bb0 MT |
622 | static inline int cgroup_attach_task_all(struct task_struct *from, |
623 | struct task_struct *t) | |
624 | { | |
625 | return 0; | |
626 | } | |
d7926ee3 | 627 | |
ddbcc7e8 PM |
628 | #endif /* !CONFIG_CGROUPS */ |
629 | ||
630 | #endif /* _LINUX_CGROUP_H */ |