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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> | |
eb6fd504 | 15 | #include <linux/rculist.h> |
846c7bb0 | 16 | #include <linux/cgroupstats.h> |
31a7df01 | 17 | #include <linux/prio_heap.h> |
cc31edce | 18 | #include <linux/rwsem.h> |
38460b48 | 19 | #include <linux/idr.h> |
48ddbe19 | 20 | #include <linux/workqueue.h> |
03b1cde6 | 21 | #include <linux/xattr.h> |
ddbcc7e8 PM |
22 | |
23 | #ifdef CONFIG_CGROUPS | |
24 | ||
25 | struct cgroupfs_root; | |
26 | struct cgroup_subsys; | |
27 | struct inode; | |
84eea842 | 28 | struct cgroup; |
38460b48 | 29 | struct css_id; |
ddbcc7e8 PM |
30 | |
31 | extern int cgroup_init_early(void); | |
32 | extern int cgroup_init(void); | |
d11c563d | 33 | extern int cgroup_lock_is_held(void); |
b4f48b63 | 34 | extern void cgroup_fork(struct task_struct *p); |
817929ec | 35 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 36 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
37 | extern int cgroupstats_build(struct cgroupstats *stats, |
38 | struct dentry *dentry); | |
e6a1105b | 39 | extern int cgroup_load_subsys(struct cgroup_subsys *ss); |
cf5d5941 | 40 | extern void cgroup_unload_subsys(struct cgroup_subsys *ss); |
ddbcc7e8 | 41 | |
828c0950 | 42 | extern const struct file_operations proc_cgroup_operations; |
a424316c | 43 | |
7d8e0bf5 LZ |
44 | /* |
45 | * Define the enumeration of all cgroup subsystems. | |
46 | * | |
47 | * We define ids for builtin subsystems and then modular ones. | |
48 | */ | |
817929ec PM |
49 | #define SUBSYS(_x) _x ## _subsys_id, |
50 | enum cgroup_subsys_id { | |
7d8e0bf5 | 51 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
817929ec | 52 | #include <linux/cgroup_subsys.h> |
7d8e0bf5 LZ |
53 | #undef IS_SUBSYS_ENABLED |
54 | CGROUP_BUILTIN_SUBSYS_COUNT, | |
55 | ||
56 | __CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1, | |
57 | ||
58 | #define IS_SUBSYS_ENABLED(option) IS_MODULE(option) | |
59 | #include <linux/cgroup_subsys.h> | |
60 | #undef IS_SUBSYS_ENABLED | |
a6f00298 | 61 | CGROUP_SUBSYS_COUNT, |
817929ec PM |
62 | }; |
63 | #undef SUBSYS | |
64 | ||
ddbcc7e8 PM |
65 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
66 | struct cgroup_subsys_state { | |
d20a390a PM |
67 | /* |
68 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 69 | * for subsystems that want to know about the cgroup |
d20a390a PM |
70 | * hierarchy structure |
71 | */ | |
ddbcc7e8 PM |
72 | struct cgroup *cgroup; |
73 | ||
d20a390a PM |
74 | /* |
75 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 76 | * to be "busy". Should be accessed via css_get(), |
d0b2fdd2 | 77 | * css_tryget() and css_put(). |
d20a390a | 78 | */ |
ddbcc7e8 PM |
79 | |
80 | atomic_t refcnt; | |
81 | ||
82 | unsigned long flags; | |
38460b48 | 83 | /* ID for this css, if possible */ |
2c392b8c | 84 | struct css_id __rcu *id; |
48ddbe19 TH |
85 | |
86 | /* Used to put @cgroup->dentry on the last css_put() */ | |
87 | struct work_struct dput_work; | |
ddbcc7e8 PM |
88 | }; |
89 | ||
90 | /* bits in struct cgroup_subsys_state flags field */ | |
91 | enum { | |
38b53aba | 92 | CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */ |
92fb9748 | 93 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
ddbcc7e8 PM |
94 | }; |
95 | ||
d7b9fff7 DN |
96 | /* Caller must verify that the css is not for root cgroup */ |
97 | static inline void __css_get(struct cgroup_subsys_state *css, int count) | |
98 | { | |
99 | atomic_add(count, &css->refcnt); | |
100 | } | |
101 | ||
ddbcc7e8 | 102 | /* |
e7c5ec91 PM |
103 | * Call css_get() to hold a reference on the css; it can be used |
104 | * for a reference obtained via: | |
105 | * - an existing ref-counted reference to the css | |
106 | * - task->cgroups for a locked task | |
ddbcc7e8 PM |
107 | */ |
108 | ||
109 | static inline void css_get(struct cgroup_subsys_state *css) | |
110 | { | |
111 | /* We don't need to reference count the root state */ | |
38b53aba | 112 | if (!(css->flags & CSS_ROOT)) |
d7b9fff7 | 113 | __css_get(css, 1); |
ddbcc7e8 | 114 | } |
e7c5ec91 | 115 | |
e7c5ec91 PM |
116 | /* |
117 | * Call css_tryget() to take a reference on a css if your existing | |
118 | * (known-valid) reference isn't already ref-counted. Returns false if | |
119 | * the css has been destroyed. | |
120 | */ | |
121 | ||
28b4c27b | 122 | extern bool __css_tryget(struct cgroup_subsys_state *css); |
e7c5ec91 PM |
123 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
124 | { | |
38b53aba | 125 | if (css->flags & CSS_ROOT) |
e7c5ec91 | 126 | return true; |
28b4c27b | 127 | return __css_tryget(css); |
e7c5ec91 PM |
128 | } |
129 | ||
ddbcc7e8 PM |
130 | /* |
131 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 132 | * css_get() or css_tryget() |
ddbcc7e8 PM |
133 | */ |
134 | ||
28b4c27b | 135 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
136 | static inline void css_put(struct cgroup_subsys_state *css) |
137 | { | |
38b53aba | 138 | if (!(css->flags & CSS_ROOT)) |
28b4c27b | 139 | __css_put(css); |
ddbcc7e8 PM |
140 | } |
141 | ||
3116f0e3 PM |
142 | /* bits in struct cgroup flags field */ |
143 | enum { | |
144 | /* Control Group is dead */ | |
145 | CGRP_REMOVED, | |
d20a390a PM |
146 | /* |
147 | * Control Group has previously had a child cgroup or a task, | |
148 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
149 | */ | |
3116f0e3 PM |
150 | CGRP_RELEASABLE, |
151 | /* Control Group requires release notifications to userspace */ | |
152 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d | 153 | /* |
2260e7fc TH |
154 | * Clone the parent's configuration when creating a new child |
155 | * cpuset cgroup. For historical reasons, this option can be | |
156 | * specified at mount time and thus is implemented here. | |
97978e6d | 157 | */ |
2260e7fc | 158 | CGRP_CPUSET_CLONE_CHILDREN, |
3116f0e3 PM |
159 | }; |
160 | ||
65dff759 LZ |
161 | struct cgroup_name { |
162 | struct rcu_head rcu_head; | |
163 | char name[]; | |
164 | }; | |
165 | ||
ddbcc7e8 PM |
166 | struct cgroup { |
167 | unsigned long flags; /* "unsigned long" so bitops work */ | |
168 | ||
d20a390a PM |
169 | /* |
170 | * count users of this cgroup. >0 means busy, but doesn't | |
171 | * necessarily indicate the number of tasks in the cgroup | |
172 | */ | |
ddbcc7e8 PM |
173 | atomic_t count; |
174 | ||
0a950f65 TH |
175 | int id; /* ida allocated in-hierarchy ID */ |
176 | ||
ddbcc7e8 PM |
177 | /* |
178 | * We link our 'sibling' struct into our parent's 'children'. | |
179 | * Our children link their 'sibling' into our 'children'. | |
180 | */ | |
181 | struct list_head sibling; /* my parent's children */ | |
182 | struct list_head children; /* my children */ | |
05ef1d7c | 183 | struct list_head files; /* my files */ |
ddbcc7e8 | 184 | |
d20a390a | 185 | struct cgroup *parent; /* my parent */ |
febfcef6 | 186 | struct dentry *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 | 187 | |
65dff759 LZ |
188 | /* |
189 | * This is a copy of dentry->d_name, and it's needed because | |
190 | * we can't use dentry->d_name in cgroup_path(). | |
191 | * | |
192 | * You must acquire rcu_read_lock() to access cgrp->name, and | |
193 | * the only place that can change it is rename(), which is | |
194 | * protected by parent dir's i_mutex. | |
195 | * | |
196 | * Normally you should use cgroup_name() wrapper rather than | |
197 | * access it directly. | |
198 | */ | |
199 | struct cgroup_name __rcu *name; | |
200 | ||
ddbcc7e8 PM |
201 | /* Private pointers for each registered subsystem */ |
202 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
203 | ||
204 | struct cgroupfs_root *root; | |
205 | struct cgroup *top_cgroup; | |
817929ec PM |
206 | |
207 | /* | |
208 | * List of cg_cgroup_links pointing at css_sets with | |
209 | * tasks in this cgroup. Protected by css_set_lock | |
210 | */ | |
211 | struct list_head css_sets; | |
81a6a5cd | 212 | |
b0ca5a84 | 213 | struct list_head allcg_node; /* cgroupfs_root->allcg_list */ |
8e3f6541 | 214 | struct list_head cft_q_node; /* used during cftype add/rm */ |
b0ca5a84 | 215 | |
81a6a5cd PM |
216 | /* |
217 | * Linked list running through all cgroups that can | |
218 | * potentially be reaped by the release agent. Protected by | |
219 | * release_list_lock | |
220 | */ | |
221 | struct list_head release_list; | |
cc31edce | 222 | |
72a8cb30 BB |
223 | /* |
224 | * list of pidlists, up to two for each namespace (one for procs, one | |
225 | * for tasks); created on demand. | |
226 | */ | |
227 | struct list_head pidlists; | |
228 | struct mutex pidlist_mutex; | |
a47295e6 PM |
229 | |
230 | /* For RCU-protected deletion */ | |
231 | struct rcu_head rcu_head; | |
be445626 | 232 | struct work_struct free_work; |
0dea1168 | 233 | |
25985edc | 234 | /* List of events which userspace want to receive */ |
0dea1168 KS |
235 | struct list_head event_list; |
236 | spinlock_t event_list_lock; | |
03b1cde6 AR |
237 | |
238 | /* directory xattrs */ | |
239 | struct simple_xattrs xattrs; | |
817929ec PM |
240 | }; |
241 | ||
d20a390a PM |
242 | /* |
243 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
244 | * cgroup_subsys_state objects. This saves space in the task struct |
245 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
246 | * list_add()/del() can bump the reference count on the entire cgroup |
247 | * set for a task. | |
817929ec PM |
248 | */ |
249 | ||
250 | struct css_set { | |
251 | ||
252 | /* Reference count */ | |
146aa1bd | 253 | atomic_t refcount; |
817929ec | 254 | |
472b1053 LZ |
255 | /* |
256 | * List running through all cgroup groups in the same hash | |
257 | * slot. Protected by css_set_lock | |
258 | */ | |
259 | struct hlist_node hlist; | |
260 | ||
817929ec PM |
261 | /* |
262 | * List running through all tasks using this cgroup | |
263 | * group. Protected by css_set_lock | |
264 | */ | |
265 | struct list_head tasks; | |
266 | ||
267 | /* | |
268 | * List of cg_cgroup_link objects on link chains from | |
269 | * cgroups referenced from this css_set. Protected by | |
270 | * css_set_lock | |
271 | */ | |
272 | struct list_head cg_links; | |
273 | ||
274 | /* | |
275 | * Set of subsystem states, one for each subsystem. This array | |
276 | * is immutable after creation apart from the init_css_set | |
cf5d5941 BB |
277 | * during subsystem registration (at boot time) and modular subsystem |
278 | * loading/unloading. | |
817929ec PM |
279 | */ |
280 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
281 | |
282 | /* For RCU-protected deletion */ | |
283 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
284 | }; |
285 | ||
91796569 PM |
286 | /* |
287 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
288 | * control files | |
289 | */ | |
290 | ||
291 | struct cgroup_map_cb { | |
292 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
293 | void *state; | |
294 | }; | |
295 | ||
d20a390a PM |
296 | /* |
297 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
298 | * |
299 | * When reading/writing to a file: | |
a043e3b2 | 300 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
301 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
302 | */ | |
303 | ||
8e3f6541 TH |
304 | /* cftype->flags */ |
305 | #define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */ | |
d0b2fdd2 | 306 | #define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create on root cg */ |
8e3f6541 TH |
307 | |
308 | #define MAX_CFTYPE_NAME 64 | |
309 | ||
ddbcc7e8 | 310 | struct cftype { |
d20a390a PM |
311 | /* |
312 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
313 | * subsystem, followed by a period. Zero length string indicates |
314 | * end of cftype array. | |
d20a390a | 315 | */ |
ddbcc7e8 PM |
316 | char name[MAX_CFTYPE_NAME]; |
317 | int private; | |
099fca32 LZ |
318 | /* |
319 | * If not 0, file mode is set to this value, otherwise it will | |
320 | * be figured out automatically | |
321 | */ | |
a5e7ed32 | 322 | umode_t mode; |
db3b1497 PM |
323 | |
324 | /* | |
325 | * If non-zero, defines the maximum length of string that can | |
326 | * be passed to write_string; defaults to 64 | |
327 | */ | |
328 | size_t max_write_len; | |
329 | ||
8e3f6541 TH |
330 | /* CFTYPE_* flags */ |
331 | unsigned int flags; | |
332 | ||
03b1cde6 AR |
333 | /* file xattrs */ |
334 | struct simple_xattrs xattrs; | |
335 | ||
ce16b49d PM |
336 | int (*open)(struct inode *inode, struct file *file); |
337 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
338 | struct file *file, | |
339 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 340 | /* |
f4c753b7 | 341 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
342 | * single integer. Use it in place of read() |
343 | */ | |
ce16b49d | 344 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
345 | /* |
346 | * read_s64() is a signed version of read_u64() | |
347 | */ | |
ce16b49d | 348 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
349 | /* |
350 | * read_map() is used for defining a map of key/value | |
351 | * pairs. It should call cb->fill(cb, key, value) for each | |
352 | * entry. The key/value pairs (and their ordering) should not | |
353 | * change between reboots. | |
354 | */ | |
ce16b49d PM |
355 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
356 | struct cgroup_map_cb *cb); | |
29486df3 SH |
357 | /* |
358 | * read_seq_string() is used for outputting a simple sequence | |
359 | * using seqfile. | |
360 | */ | |
ce16b49d PM |
361 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
362 | struct seq_file *m); | |
91796569 | 363 | |
ce16b49d PM |
364 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
365 | struct file *file, | |
366 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
367 | |
368 | /* | |
f4c753b7 | 369 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
370 | * a single integer (as parsed by simple_strtoull) from |
371 | * userspace. Use in place of write(); return 0 or error. | |
372 | */ | |
ce16b49d | 373 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
374 | /* |
375 | * write_s64() is a signed version of write_u64() | |
376 | */ | |
ce16b49d | 377 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 378 | |
db3b1497 PM |
379 | /* |
380 | * write_string() is passed a nul-terminated kernelspace | |
381 | * buffer of maximum length determined by max_write_len. | |
382 | * Returns 0 or -ve error code. | |
383 | */ | |
384 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
385 | const char *buffer); | |
d447ea2f PE |
386 | /* |
387 | * trigger() callback can be used to get some kick from the | |
388 | * userspace, when the actual string written is not important | |
389 | * at all. The private field can be used to determine the | |
390 | * kick type for multiplexing. | |
391 | */ | |
392 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
393 | ||
ce16b49d | 394 | int (*release)(struct inode *inode, struct file *file); |
0dea1168 KS |
395 | |
396 | /* | |
397 | * register_event() callback will be used to add new userspace | |
398 | * waiter for changes related to the cftype. Implement it if | |
399 | * you want to provide this functionality. Use eventfd_signal() | |
400 | * on eventfd to send notification to userspace. | |
401 | */ | |
402 | int (*register_event)(struct cgroup *cgrp, struct cftype *cft, | |
403 | struct eventfd_ctx *eventfd, const char *args); | |
404 | /* | |
405 | * unregister_event() callback will be called when userspace | |
406 | * closes the eventfd or on cgroup removing. | |
407 | * This callback must be implemented, if you want provide | |
408 | * notification functionality. | |
0dea1168 | 409 | */ |
907860ed | 410 | void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
0dea1168 | 411 | struct eventfd_ctx *eventfd); |
ddbcc7e8 PM |
412 | }; |
413 | ||
8e3f6541 TH |
414 | /* |
415 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
416 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
417 | * terminated by zero length name. | |
418 | */ | |
419 | struct cftype_set { | |
420 | struct list_head node; /* chained at subsys->cftsets */ | |
03b1cde6 | 421 | struct cftype *cfts; |
8e3f6541 TH |
422 | }; |
423 | ||
31a7df01 CW |
424 | struct cgroup_scanner { |
425 | struct cgroup *cg; | |
426 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
427 | void (*process_task)(struct task_struct *p, | |
428 | struct cgroup_scanner *scan); | |
429 | struct ptr_heap *heap; | |
bd1a8ab7 | 430 | void *data; |
31a7df01 CW |
431 | }; |
432 | ||
65dff759 LZ |
433 | /* Caller should hold rcu_read_lock() */ |
434 | static inline const char *cgroup_name(const struct cgroup *cgrp) | |
435 | { | |
436 | return rcu_dereference(cgrp->name)->name; | |
437 | } | |
438 | ||
03b1cde6 AR |
439 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
440 | int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
8e3f6541 | 441 | |
ffd2d883 | 442 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 443 | |
ffd2d883 | 444 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 445 | |
ffd2d883 | 446 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 447 | |
2f7ee569 TH |
448 | /* |
449 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
450 | * methods. | |
451 | */ | |
452 | struct cgroup_taskset; | |
453 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
454 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
455 | struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset); | |
456 | int cgroup_taskset_size(struct cgroup_taskset *tset); | |
457 | ||
458 | /** | |
459 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
460 | * @task: the loop cursor | |
461 | * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all | |
462 | * @tset: taskset to iterate | |
463 | */ | |
464 | #define cgroup_taskset_for_each(task, skip_cgrp, tset) \ | |
465 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
466 | (task) = cgroup_taskset_next((tset))) \ | |
467 | if (!(skip_cgrp) || \ | |
468 | cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp)) | |
469 | ||
21acb9ca TLSC |
470 | /* |
471 | * Control Group subsystem type. | |
472 | * See Documentation/cgroups/cgroups.txt for details | |
473 | */ | |
ddbcc7e8 PM |
474 | |
475 | struct cgroup_subsys { | |
92fb9748 TH |
476 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup *cgrp); |
477 | int (*css_online)(struct cgroup *cgrp); | |
478 | void (*css_offline)(struct cgroup *cgrp); | |
479 | void (*css_free)(struct cgroup *cgrp); | |
480 | ||
761b3ef5 LZ |
481 | int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); |
482 | void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
483 | void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
484 | void (*fork)(struct task_struct *task); | |
485 | void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp, | |
486 | struct task_struct *task); | |
761b3ef5 | 487 | void (*bind)(struct cgroup *root); |
e5991371 | 488 | |
ddbcc7e8 PM |
489 | int subsys_id; |
490 | int active; | |
8bab8dde | 491 | int disabled; |
ddbcc7e8 | 492 | int early_init; |
38460b48 KH |
493 | /* |
494 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
495 | * (not available in early_init time.) | |
496 | */ | |
497 | bool use_id; | |
48ddbe19 | 498 | |
8c7f6edb TH |
499 | /* |
500 | * If %false, this subsystem is properly hierarchical - | |
501 | * configuration, resource accounting and restriction on a parent | |
502 | * cgroup cover those of its children. If %true, hierarchy support | |
503 | * is broken in some ways - some subsystems ignore hierarchy | |
504 | * completely while others are only implemented half-way. | |
505 | * | |
506 | * It's now disallowed to create nested cgroups if the subsystem is | |
507 | * broken and cgroup core will emit a warning message on such | |
508 | * cases. Eventually, all subsystems will be made properly | |
509 | * hierarchical and this will go away. | |
510 | */ | |
511 | bool broken_hierarchy; | |
512 | bool warned_broken_hierarchy; | |
513 | ||
ddbcc7e8 PM |
514 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
515 | const char *name; | |
516 | ||
999cd8a4 PM |
517 | /* |
518 | * Link to parent, and list entry in parent's children. | |
6be96a5c | 519 | * Protected by cgroup_lock() |
999cd8a4 PM |
520 | */ |
521 | struct cgroupfs_root *root; | |
ddbcc7e8 | 522 | struct list_head sibling; |
38460b48 KH |
523 | /* used when use_id == true */ |
524 | struct idr idr; | |
42aee6c4 | 525 | spinlock_t id_lock; |
e6a1105b | 526 | |
8e3f6541 TH |
527 | /* list of cftype_sets */ |
528 | struct list_head cftsets; | |
529 | ||
530 | /* base cftypes, automatically [de]registered with subsys itself */ | |
531 | struct cftype *base_cftypes; | |
532 | struct cftype_set base_cftset; | |
533 | ||
e6a1105b BB |
534 | /* should be defined only by modular subsystems */ |
535 | struct module *module; | |
ddbcc7e8 PM |
536 | }; |
537 | ||
538 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
5fc0b025 | 539 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
ddbcc7e8 | 540 | #include <linux/cgroup_subsys.h> |
5fc0b025 | 541 | #undef IS_SUBSYS_ENABLED |
ddbcc7e8 PM |
542 | #undef SUBSYS |
543 | ||
544 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 545 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 546 | { |
ffd2d883 | 547 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
548 | } |
549 | ||
dc61b1d6 PZ |
550 | /* |
551 | * function to get the cgroup_subsys_state which allows for extra | |
552 | * rcu_dereference_check() conditions, such as locks used during the | |
553 | * cgroup_subsys::attach() methods. | |
554 | */ | |
555 | #define task_subsys_state_check(task, subsys_id, __c) \ | |
556 | rcu_dereference_check(task->cgroups->subsys[subsys_id], \ | |
dc61b1d6 PZ |
557 | lockdep_is_held(&task->alloc_lock) || \ |
558 | cgroup_lock_is_held() || (__c)) | |
559 | ||
560 | static inline struct cgroup_subsys_state * | |
561 | task_subsys_state(struct task_struct *task, int subsys_id) | |
ddbcc7e8 | 562 | { |
dc61b1d6 | 563 | return task_subsys_state_check(task, subsys_id, false); |
ddbcc7e8 PM |
564 | } |
565 | ||
566 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
567 | int subsys_id) | |
568 | { | |
569 | return task_subsys_state(task, subsys_id)->cgroup; | |
570 | } | |
571 | ||
574bd9f7 TH |
572 | /** |
573 | * cgroup_for_each_child - iterate through children of a cgroup | |
574 | * @pos: the cgroup * to use as the loop cursor | |
575 | * @cgroup: cgroup whose children to walk | |
576 | * | |
577 | * Walk @cgroup's children. Must be called under rcu_read_lock(). A child | |
92fb9748 TH |
578 | * cgroup which hasn't finished ->css_online() or already has finished |
579 | * ->css_offline() may show up during traversal and it's each subsystem's | |
574bd9f7 TH |
580 | * responsibility to verify that each @pos is alive. |
581 | * | |
92fb9748 TH |
582 | * If a subsystem synchronizes against the parent in its ->css_online() and |
583 | * before starting iterating, a cgroup which finished ->css_online() is | |
584 | * guaranteed to be visible in the future iterations. | |
574bd9f7 TH |
585 | */ |
586 | #define cgroup_for_each_child(pos, cgroup) \ | |
587 | list_for_each_entry_rcu(pos, &(cgroup)->children, sibling) | |
588 | ||
589 | struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos, | |
590 | struct cgroup *cgroup); | |
12a9d2fe | 591 | struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos); |
574bd9f7 TH |
592 | |
593 | /** | |
594 | * cgroup_for_each_descendant_pre - pre-order walk of a cgroup's descendants | |
595 | * @pos: the cgroup * to use as the loop cursor | |
596 | * @cgroup: cgroup whose descendants to walk | |
597 | * | |
598 | * Walk @cgroup's descendants. Must be called under rcu_read_lock(). A | |
92fb9748 TH |
599 | * descendant cgroup which hasn't finished ->css_online() or already has |
600 | * finished ->css_offline() may show up during traversal and it's each | |
574bd9f7 TH |
601 | * subsystem's responsibility to verify that each @pos is alive. |
602 | * | |
92fb9748 TH |
603 | * If a subsystem synchronizes against the parent in its ->css_online() and |
604 | * before starting iterating, and synchronizes against @pos on each | |
605 | * iteration, any descendant cgroup which finished ->css_offline() is | |
574bd9f7 TH |
606 | * guaranteed to be visible in the future iterations. |
607 | * | |
608 | * In other words, the following guarantees that a descendant can't escape | |
609 | * state updates of its ancestors. | |
610 | * | |
92fb9748 | 611 | * my_online(@cgrp) |
574bd9f7 TH |
612 | * { |
613 | * Lock @cgrp->parent and @cgrp; | |
614 | * Inherit state from @cgrp->parent; | |
615 | * Unlock both. | |
616 | * } | |
617 | * | |
618 | * my_update_state(@cgrp) | |
619 | * { | |
620 | * Lock @cgrp; | |
621 | * Update @cgrp's state; | |
622 | * Unlock @cgrp; | |
623 | * | |
624 | * cgroup_for_each_descendant_pre(@pos, @cgrp) { | |
625 | * Lock @pos; | |
626 | * Verify @pos is alive and inherit state from @pos->parent; | |
627 | * Unlock @pos; | |
628 | * } | |
629 | * } | |
630 | * | |
631 | * As long as the inheriting step, including checking the parent state, is | |
632 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
633 | * while inheriting. The state update to the parent is guaranteed to be | |
634 | * visible by walking order and, as long as inheriting operations to the | |
635 | * same @pos are atomic to each other, multiple updates racing each other | |
636 | * still result in the correct state. It's guaranateed that at least one | |
637 | * inheritance happens for any cgroup after the latest update to its | |
638 | * parent. | |
639 | * | |
640 | * If checking parent's state requires locking the parent, each inheriting | |
641 | * iteration should lock and unlock both @pos->parent and @pos. | |
642 | * | |
643 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 644 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 TH |
645 | * operations. |
646 | */ | |
647 | #define cgroup_for_each_descendant_pre(pos, cgroup) \ | |
648 | for (pos = cgroup_next_descendant_pre(NULL, (cgroup)); (pos); \ | |
649 | pos = cgroup_next_descendant_pre((pos), (cgroup))) | |
650 | ||
651 | struct cgroup *cgroup_next_descendant_post(struct cgroup *pos, | |
652 | struct cgroup *cgroup); | |
653 | ||
654 | /** | |
655 | * cgroup_for_each_descendant_post - post-order walk of a cgroup's descendants | |
656 | * @pos: the cgroup * to use as the loop cursor | |
657 | * @cgroup: cgroup whose descendants to walk | |
658 | * | |
659 | * Similar to cgroup_for_each_descendant_pre() but performs post-order | |
660 | * traversal instead. Note that the walk visibility guarantee described in | |
661 | * pre-order walk doesn't apply the same to post-order walks. | |
662 | */ | |
663 | #define cgroup_for_each_descendant_post(pos, cgroup) \ | |
664 | for (pos = cgroup_next_descendant_post(NULL, (cgroup)); (pos); \ | |
665 | pos = cgroup_next_descendant_post((pos), (cgroup))) | |
666 | ||
817929ec PM |
667 | /* A cgroup_iter should be treated as an opaque object */ |
668 | struct cgroup_iter { | |
669 | struct list_head *cg_link; | |
670 | struct list_head *task; | |
671 | }; | |
672 | ||
d20a390a PM |
673 | /* |
674 | * To iterate across the tasks in a cgroup: | |
817929ec | 675 | * |
b595076a | 676 | * 1) call cgroup_iter_start to initialize an iterator |
817929ec PM |
677 | * |
678 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
679 | * returns NULL or until you want to end the iteration | |
680 | * | |
681 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 682 | * |
d20a390a PM |
683 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
684 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
685 | * the test_task() callback, but not while calling the process_task() | |
686 | * callback. | |
817929ec | 687 | */ |
ffd2d883 LZ |
688 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
689 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 690 | struct cgroup_iter *it); |
ffd2d883 | 691 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 692 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
31583bb0 | 693 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 694 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 695 | |
38460b48 KH |
696 | /* |
697 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
698 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
699 | * CSS ID is assigned at cgroup allocation (create) automatically | |
700 | * and removed when subsys calls free_css_id() function. This is because | |
701 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
702 | * | |
703 | * Looking up and scanning function should be called under rcu_read_lock(). | |
6be96a5c | 704 | * Taking cgroup_mutex is not necessary for following calls. |
38460b48 KH |
705 | * But the css returned by this routine can be "not populated yet" or "being |
706 | * destroyed". The caller should check css and cgroup's status. | |
707 | */ | |
708 | ||
709 | /* | |
710 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
711 | * cgroup_subsys_state. | |
712 | */ | |
713 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
714 | ||
715 | /* Find a cgroup_subsys_state which has given ID */ | |
716 | ||
717 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
718 | ||
719 | /* | |
720 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
721 | * Returning a cgroup_subsys_state or NULL. | |
722 | */ | |
723 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
724 | struct cgroup_subsys_state *root, int *foundid); | |
725 | ||
726 | /* Returns true if root is ancestor of cg */ | |
727 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 728 | const struct cgroup_subsys_state *root); |
38460b48 KH |
729 | |
730 | /* Get id and depth of css */ | |
731 | unsigned short css_id(struct cgroup_subsys_state *css); | |
732 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
e5d1367f | 733 | struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); |
38460b48 | 734 | |
ddbcc7e8 PM |
735 | #else /* !CONFIG_CGROUPS */ |
736 | ||
737 | static inline int cgroup_init_early(void) { return 0; } | |
738 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 739 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 740 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 741 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
742 | |
743 | static inline void cgroup_lock(void) {} | |
744 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
745 | static inline int cgroupstats_build(struct cgroupstats *stats, |
746 | struct dentry *dentry) | |
747 | { | |
748 | return -EINVAL; | |
749 | } | |
ddbcc7e8 | 750 | |
d7926ee3 | 751 | /* No cgroups - nothing to do */ |
31583bb0 MT |
752 | static inline int cgroup_attach_task_all(struct task_struct *from, |
753 | struct task_struct *t) | |
754 | { | |
755 | return 0; | |
756 | } | |
d7926ee3 | 757 | |
ddbcc7e8 PM |
758 | #endif /* !CONFIG_CGROUPS */ |
759 | ||
760 | #endif /* _LINUX_CGROUP_H */ |