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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> |
25a7e684 | 22 | #include <linux/fs.h> |
ddbcc7e8 PM |
23 | |
24 | #ifdef CONFIG_CGROUPS | |
25 | ||
26 | struct cgroupfs_root; | |
27 | struct cgroup_subsys; | |
28 | struct inode; | |
84eea842 | 29 | struct cgroup; |
38460b48 | 30 | struct css_id; |
ddbcc7e8 PM |
31 | |
32 | extern int cgroup_init_early(void); | |
33 | extern int cgroup_init(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 | ||
25a7e684 TH |
242 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
243 | ||
244 | /* cgroupfs_root->flags */ | |
245 | enum { | |
246 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ | |
247 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
248 | }; | |
249 | ||
250 | /* | |
251 | * A cgroupfs_root represents the root of a cgroup hierarchy, and may be | |
252 | * associated with a superblock to form an active hierarchy. This is | |
253 | * internal to cgroup core. Don't access directly from controllers. | |
254 | */ | |
255 | struct cgroupfs_root { | |
256 | struct super_block *sb; | |
257 | ||
258 | /* | |
259 | * The bitmask of subsystems intended to be attached to this | |
260 | * hierarchy | |
261 | */ | |
262 | unsigned long subsys_mask; | |
263 | ||
264 | /* Unique id for this hierarchy. */ | |
265 | int hierarchy_id; | |
266 | ||
267 | /* The bitmask of subsystems currently attached to this hierarchy */ | |
268 | unsigned long actual_subsys_mask; | |
269 | ||
270 | /* A list running through the attached subsystems */ | |
271 | struct list_head subsys_list; | |
272 | ||
273 | /* The root cgroup for this hierarchy */ | |
274 | struct cgroup top_cgroup; | |
275 | ||
276 | /* Tracks how many cgroups are currently defined in hierarchy.*/ | |
277 | int number_of_cgroups; | |
278 | ||
279 | /* A list running through the active hierarchies */ | |
280 | struct list_head root_list; | |
281 | ||
282 | /* All cgroups on this root, cgroup_mutex protected */ | |
283 | struct list_head allcg_list; | |
284 | ||
285 | /* Hierarchy-specific flags */ | |
286 | unsigned long flags; | |
287 | ||
288 | /* IDs for cgroups in this hierarchy */ | |
289 | struct ida cgroup_ida; | |
290 | ||
291 | /* The path to use for release notifications. */ | |
292 | char release_agent_path[PATH_MAX]; | |
293 | ||
294 | /* The name for this hierarchy - may be empty */ | |
295 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
296 | }; | |
297 | ||
d20a390a PM |
298 | /* |
299 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
300 | * cgroup_subsys_state objects. This saves space in the task struct |
301 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
302 | * list_add()/del() can bump the reference count on the entire cgroup |
303 | * set for a task. | |
817929ec PM |
304 | */ |
305 | ||
306 | struct css_set { | |
307 | ||
308 | /* Reference count */ | |
146aa1bd | 309 | atomic_t refcount; |
817929ec | 310 | |
472b1053 LZ |
311 | /* |
312 | * List running through all cgroup groups in the same hash | |
313 | * slot. Protected by css_set_lock | |
314 | */ | |
315 | struct hlist_node hlist; | |
316 | ||
817929ec PM |
317 | /* |
318 | * List running through all tasks using this cgroup | |
319 | * group. Protected by css_set_lock | |
320 | */ | |
321 | struct list_head tasks; | |
322 | ||
323 | /* | |
324 | * List of cg_cgroup_link objects on link chains from | |
325 | * cgroups referenced from this css_set. Protected by | |
326 | * css_set_lock | |
327 | */ | |
328 | struct list_head cg_links; | |
329 | ||
330 | /* | |
331 | * Set of subsystem states, one for each subsystem. This array | |
332 | * is immutable after creation apart from the init_css_set | |
cf5d5941 BB |
333 | * during subsystem registration (at boot time) and modular subsystem |
334 | * loading/unloading. | |
817929ec PM |
335 | */ |
336 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
337 | |
338 | /* For RCU-protected deletion */ | |
339 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
340 | }; |
341 | ||
91796569 PM |
342 | /* |
343 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
344 | * control files | |
345 | */ | |
346 | ||
347 | struct cgroup_map_cb { | |
348 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
349 | void *state; | |
350 | }; | |
351 | ||
d20a390a PM |
352 | /* |
353 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
354 | * |
355 | * When reading/writing to a file: | |
a043e3b2 | 356 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
357 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
358 | */ | |
359 | ||
8e3f6541 TH |
360 | /* cftype->flags */ |
361 | #define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */ | |
d0b2fdd2 | 362 | #define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create on root cg */ |
8e3f6541 TH |
363 | |
364 | #define MAX_CFTYPE_NAME 64 | |
365 | ||
ddbcc7e8 | 366 | struct cftype { |
d20a390a PM |
367 | /* |
368 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
369 | * subsystem, followed by a period. Zero length string indicates |
370 | * end of cftype array. | |
d20a390a | 371 | */ |
ddbcc7e8 PM |
372 | char name[MAX_CFTYPE_NAME]; |
373 | int private; | |
099fca32 LZ |
374 | /* |
375 | * If not 0, file mode is set to this value, otherwise it will | |
376 | * be figured out automatically | |
377 | */ | |
a5e7ed32 | 378 | umode_t mode; |
db3b1497 PM |
379 | |
380 | /* | |
381 | * If non-zero, defines the maximum length of string that can | |
382 | * be passed to write_string; defaults to 64 | |
383 | */ | |
384 | size_t max_write_len; | |
385 | ||
8e3f6541 TH |
386 | /* CFTYPE_* flags */ |
387 | unsigned int flags; | |
388 | ||
03b1cde6 AR |
389 | /* file xattrs */ |
390 | struct simple_xattrs xattrs; | |
391 | ||
ce16b49d PM |
392 | int (*open)(struct inode *inode, struct file *file); |
393 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
394 | struct file *file, | |
395 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 396 | /* |
f4c753b7 | 397 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
398 | * single integer. Use it in place of read() |
399 | */ | |
ce16b49d | 400 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
401 | /* |
402 | * read_s64() is a signed version of read_u64() | |
403 | */ | |
ce16b49d | 404 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
405 | /* |
406 | * read_map() is used for defining a map of key/value | |
407 | * pairs. It should call cb->fill(cb, key, value) for each | |
408 | * entry. The key/value pairs (and their ordering) should not | |
409 | * change between reboots. | |
410 | */ | |
ce16b49d PM |
411 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
412 | struct cgroup_map_cb *cb); | |
29486df3 SH |
413 | /* |
414 | * read_seq_string() is used for outputting a simple sequence | |
415 | * using seqfile. | |
416 | */ | |
ce16b49d PM |
417 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
418 | struct seq_file *m); | |
91796569 | 419 | |
ce16b49d PM |
420 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
421 | struct file *file, | |
422 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
423 | |
424 | /* | |
f4c753b7 | 425 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
426 | * a single integer (as parsed by simple_strtoull) from |
427 | * userspace. Use in place of write(); return 0 or error. | |
428 | */ | |
ce16b49d | 429 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
430 | /* |
431 | * write_s64() is a signed version of write_u64() | |
432 | */ | |
ce16b49d | 433 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 434 | |
db3b1497 PM |
435 | /* |
436 | * write_string() is passed a nul-terminated kernelspace | |
437 | * buffer of maximum length determined by max_write_len. | |
438 | * Returns 0 or -ve error code. | |
439 | */ | |
440 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
441 | const char *buffer); | |
d447ea2f PE |
442 | /* |
443 | * trigger() callback can be used to get some kick from the | |
444 | * userspace, when the actual string written is not important | |
445 | * at all. The private field can be used to determine the | |
446 | * kick type for multiplexing. | |
447 | */ | |
448 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
449 | ||
ce16b49d | 450 | int (*release)(struct inode *inode, struct file *file); |
0dea1168 KS |
451 | |
452 | /* | |
453 | * register_event() callback will be used to add new userspace | |
454 | * waiter for changes related to the cftype. Implement it if | |
455 | * you want to provide this functionality. Use eventfd_signal() | |
456 | * on eventfd to send notification to userspace. | |
457 | */ | |
458 | int (*register_event)(struct cgroup *cgrp, struct cftype *cft, | |
459 | struct eventfd_ctx *eventfd, const char *args); | |
460 | /* | |
461 | * unregister_event() callback will be called when userspace | |
462 | * closes the eventfd or on cgroup removing. | |
463 | * This callback must be implemented, if you want provide | |
464 | * notification functionality. | |
0dea1168 | 465 | */ |
907860ed | 466 | void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
0dea1168 | 467 | struct eventfd_ctx *eventfd); |
ddbcc7e8 PM |
468 | }; |
469 | ||
8e3f6541 TH |
470 | /* |
471 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
472 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
473 | * terminated by zero length name. | |
474 | */ | |
475 | struct cftype_set { | |
476 | struct list_head node; /* chained at subsys->cftsets */ | |
03b1cde6 | 477 | struct cftype *cfts; |
8e3f6541 TH |
478 | }; |
479 | ||
31a7df01 CW |
480 | struct cgroup_scanner { |
481 | struct cgroup *cg; | |
482 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
483 | void (*process_task)(struct task_struct *p, | |
484 | struct cgroup_scanner *scan); | |
485 | struct ptr_heap *heap; | |
bd1a8ab7 | 486 | void *data; |
31a7df01 CW |
487 | }; |
488 | ||
65dff759 LZ |
489 | /* Caller should hold rcu_read_lock() */ |
490 | static inline const char *cgroup_name(const struct cgroup *cgrp) | |
491 | { | |
492 | return rcu_dereference(cgrp->name)->name; | |
493 | } | |
494 | ||
03b1cde6 AR |
495 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
496 | int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
8e3f6541 | 497 | |
ffd2d883 | 498 | int cgroup_is_removed(const struct cgroup *cgrp); |
78574cf9 | 499 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
ddbcc7e8 | 500 | |
ffd2d883 | 501 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 502 | |
ffd2d883 | 503 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 504 | |
2f7ee569 TH |
505 | /* |
506 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
507 | * methods. | |
508 | */ | |
509 | struct cgroup_taskset; | |
510 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
511 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
512 | struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset); | |
513 | int cgroup_taskset_size(struct cgroup_taskset *tset); | |
514 | ||
515 | /** | |
516 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
517 | * @task: the loop cursor | |
518 | * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all | |
519 | * @tset: taskset to iterate | |
520 | */ | |
521 | #define cgroup_taskset_for_each(task, skip_cgrp, tset) \ | |
522 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
523 | (task) = cgroup_taskset_next((tset))) \ | |
524 | if (!(skip_cgrp) || \ | |
525 | cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp)) | |
526 | ||
21acb9ca TLSC |
527 | /* |
528 | * Control Group subsystem type. | |
529 | * See Documentation/cgroups/cgroups.txt for details | |
530 | */ | |
ddbcc7e8 PM |
531 | |
532 | struct cgroup_subsys { | |
92fb9748 TH |
533 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup *cgrp); |
534 | int (*css_online)(struct cgroup *cgrp); | |
535 | void (*css_offline)(struct cgroup *cgrp); | |
536 | void (*css_free)(struct cgroup *cgrp); | |
537 | ||
761b3ef5 LZ |
538 | int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); |
539 | void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
540 | void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
541 | void (*fork)(struct task_struct *task); | |
542 | void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp, | |
543 | struct task_struct *task); | |
26d5bbe5 TH |
544 | void (*bind)(struct cgroup *root); |
545 | ||
ddbcc7e8 PM |
546 | int subsys_id; |
547 | int active; | |
8bab8dde | 548 | int disabled; |
ddbcc7e8 | 549 | int early_init; |
38460b48 KH |
550 | /* |
551 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
552 | * (not available in early_init time.) | |
553 | */ | |
554 | bool use_id; | |
48ddbe19 | 555 | |
8c7f6edb TH |
556 | /* |
557 | * If %false, this subsystem is properly hierarchical - | |
558 | * configuration, resource accounting and restriction on a parent | |
559 | * cgroup cover those of its children. If %true, hierarchy support | |
560 | * is broken in some ways - some subsystems ignore hierarchy | |
561 | * completely while others are only implemented half-way. | |
562 | * | |
563 | * It's now disallowed to create nested cgroups if the subsystem is | |
564 | * broken and cgroup core will emit a warning message on such | |
565 | * cases. Eventually, all subsystems will be made properly | |
566 | * hierarchical and this will go away. | |
567 | */ | |
568 | bool broken_hierarchy; | |
569 | bool warned_broken_hierarchy; | |
570 | ||
ddbcc7e8 PM |
571 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
572 | const char *name; | |
573 | ||
999cd8a4 PM |
574 | /* |
575 | * Link to parent, and list entry in parent's children. | |
6be96a5c | 576 | * Protected by cgroup_lock() |
999cd8a4 PM |
577 | */ |
578 | struct cgroupfs_root *root; | |
ddbcc7e8 | 579 | struct list_head sibling; |
38460b48 KH |
580 | /* used when use_id == true */ |
581 | struct idr idr; | |
42aee6c4 | 582 | spinlock_t id_lock; |
e6a1105b | 583 | |
8e3f6541 TH |
584 | /* list of cftype_sets */ |
585 | struct list_head cftsets; | |
586 | ||
587 | /* base cftypes, automatically [de]registered with subsys itself */ | |
588 | struct cftype *base_cftypes; | |
589 | struct cftype_set base_cftset; | |
590 | ||
e6a1105b BB |
591 | /* should be defined only by modular subsystems */ |
592 | struct module *module; | |
ddbcc7e8 PM |
593 | }; |
594 | ||
595 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
5fc0b025 | 596 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
ddbcc7e8 | 597 | #include <linux/cgroup_subsys.h> |
5fc0b025 | 598 | #undef IS_SUBSYS_ENABLED |
ddbcc7e8 PM |
599 | #undef SUBSYS |
600 | ||
601 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 602 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 603 | { |
ffd2d883 | 604 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
605 | } |
606 | ||
dc61b1d6 PZ |
607 | /* |
608 | * function to get the cgroup_subsys_state which allows for extra | |
609 | * rcu_dereference_check() conditions, such as locks used during the | |
610 | * cgroup_subsys::attach() methods. | |
611 | */ | |
2219449a TH |
612 | #ifdef CONFIG_PROVE_RCU |
613 | extern struct mutex cgroup_mutex; | |
dc61b1d6 | 614 | #define task_subsys_state_check(task, subsys_id, __c) \ |
2219449a TH |
615 | rcu_dereference_check((task)->cgroups->subsys[(subsys_id)], \ |
616 | lockdep_is_held(&(task)->alloc_lock) || \ | |
617 | lockdep_is_held(&cgroup_mutex) || (__c)) | |
618 | #else | |
619 | #define task_subsys_state_check(task, subsys_id, __c) \ | |
620 | rcu_dereference((task)->cgroups->subsys[(subsys_id)]) | |
621 | #endif | |
dc61b1d6 PZ |
622 | |
623 | static inline struct cgroup_subsys_state * | |
624 | task_subsys_state(struct task_struct *task, int subsys_id) | |
ddbcc7e8 | 625 | { |
dc61b1d6 | 626 | return task_subsys_state_check(task, subsys_id, false); |
ddbcc7e8 PM |
627 | } |
628 | ||
629 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
630 | int subsys_id) | |
631 | { | |
632 | return task_subsys_state(task, subsys_id)->cgroup; | |
633 | } | |
634 | ||
574bd9f7 TH |
635 | /** |
636 | * cgroup_for_each_child - iterate through children of a cgroup | |
637 | * @pos: the cgroup * to use as the loop cursor | |
638 | * @cgroup: cgroup whose children to walk | |
639 | * | |
640 | * Walk @cgroup's children. Must be called under rcu_read_lock(). A child | |
92fb9748 TH |
641 | * cgroup which hasn't finished ->css_online() or already has finished |
642 | * ->css_offline() may show up during traversal and it's each subsystem's | |
574bd9f7 TH |
643 | * responsibility to verify that each @pos is alive. |
644 | * | |
92fb9748 TH |
645 | * If a subsystem synchronizes against the parent in its ->css_online() and |
646 | * before starting iterating, a cgroup which finished ->css_online() is | |
647 | * guaranteed to be visible in the future iterations. | |
574bd9f7 TH |
648 | */ |
649 | #define cgroup_for_each_child(pos, cgroup) \ | |
650 | list_for_each_entry_rcu(pos, &(cgroup)->children, sibling) | |
651 | ||
652 | struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos, | |
653 | struct cgroup *cgroup); | |
12a9d2fe | 654 | struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos); |
574bd9f7 TH |
655 | |
656 | /** | |
657 | * cgroup_for_each_descendant_pre - pre-order walk of a cgroup's descendants | |
658 | * @pos: the cgroup * to use as the loop cursor | |
659 | * @cgroup: cgroup whose descendants to walk | |
660 | * | |
661 | * Walk @cgroup's descendants. Must be called under rcu_read_lock(). A | |
92fb9748 TH |
662 | * descendant cgroup which hasn't finished ->css_online() or already has |
663 | * finished ->css_offline() may show up during traversal and it's each | |
574bd9f7 TH |
664 | * subsystem's responsibility to verify that each @pos is alive. |
665 | * | |
92fb9748 TH |
666 | * If a subsystem synchronizes against the parent in its ->css_online() and |
667 | * before starting iterating, and synchronizes against @pos on each | |
668 | * iteration, any descendant cgroup which finished ->css_offline() is | |
574bd9f7 TH |
669 | * guaranteed to be visible in the future iterations. |
670 | * | |
671 | * In other words, the following guarantees that a descendant can't escape | |
672 | * state updates of its ancestors. | |
673 | * | |
92fb9748 | 674 | * my_online(@cgrp) |
574bd9f7 TH |
675 | * { |
676 | * Lock @cgrp->parent and @cgrp; | |
677 | * Inherit state from @cgrp->parent; | |
678 | * Unlock both. | |
679 | * } | |
680 | * | |
681 | * my_update_state(@cgrp) | |
682 | * { | |
683 | * Lock @cgrp; | |
684 | * Update @cgrp's state; | |
685 | * Unlock @cgrp; | |
686 | * | |
687 | * cgroup_for_each_descendant_pre(@pos, @cgrp) { | |
688 | * Lock @pos; | |
689 | * Verify @pos is alive and inherit state from @pos->parent; | |
690 | * Unlock @pos; | |
691 | * } | |
692 | * } | |
693 | * | |
694 | * As long as the inheriting step, including checking the parent state, is | |
695 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
696 | * while inheriting. The state update to the parent is guaranteed to be | |
697 | * visible by walking order and, as long as inheriting operations to the | |
698 | * same @pos are atomic to each other, multiple updates racing each other | |
699 | * still result in the correct state. It's guaranateed that at least one | |
700 | * inheritance happens for any cgroup after the latest update to its | |
701 | * parent. | |
702 | * | |
703 | * If checking parent's state requires locking the parent, each inheriting | |
704 | * iteration should lock and unlock both @pos->parent and @pos. | |
705 | * | |
706 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 707 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 TH |
708 | * operations. |
709 | */ | |
710 | #define cgroup_for_each_descendant_pre(pos, cgroup) \ | |
711 | for (pos = cgroup_next_descendant_pre(NULL, (cgroup)); (pos); \ | |
712 | pos = cgroup_next_descendant_pre((pos), (cgroup))) | |
713 | ||
714 | struct cgroup *cgroup_next_descendant_post(struct cgroup *pos, | |
715 | struct cgroup *cgroup); | |
716 | ||
717 | /** | |
718 | * cgroup_for_each_descendant_post - post-order walk of a cgroup's descendants | |
719 | * @pos: the cgroup * to use as the loop cursor | |
720 | * @cgroup: cgroup whose descendants to walk | |
721 | * | |
722 | * Similar to cgroup_for_each_descendant_pre() but performs post-order | |
723 | * traversal instead. Note that the walk visibility guarantee described in | |
724 | * pre-order walk doesn't apply the same to post-order walks. | |
725 | */ | |
726 | #define cgroup_for_each_descendant_post(pos, cgroup) \ | |
727 | for (pos = cgroup_next_descendant_post(NULL, (cgroup)); (pos); \ | |
728 | pos = cgroup_next_descendant_post((pos), (cgroup))) | |
729 | ||
817929ec PM |
730 | /* A cgroup_iter should be treated as an opaque object */ |
731 | struct cgroup_iter { | |
732 | struct list_head *cg_link; | |
733 | struct list_head *task; | |
734 | }; | |
735 | ||
d20a390a PM |
736 | /* |
737 | * To iterate across the tasks in a cgroup: | |
817929ec | 738 | * |
b595076a | 739 | * 1) call cgroup_iter_start to initialize an iterator |
817929ec PM |
740 | * |
741 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
742 | * returns NULL or until you want to end the iteration | |
743 | * | |
744 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 745 | * |
d20a390a PM |
746 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
747 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
748 | * the test_task() callback, but not while calling the process_task() | |
749 | * callback. | |
817929ec | 750 | */ |
ffd2d883 LZ |
751 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
752 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 753 | struct cgroup_iter *it); |
ffd2d883 | 754 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 755 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
31583bb0 | 756 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 757 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 758 | |
38460b48 KH |
759 | /* |
760 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
761 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
762 | * CSS ID is assigned at cgroup allocation (create) automatically | |
763 | * and removed when subsys calls free_css_id() function. This is because | |
764 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
765 | * | |
766 | * Looking up and scanning function should be called under rcu_read_lock(). | |
6be96a5c | 767 | * Taking cgroup_mutex is not necessary for following calls. |
38460b48 KH |
768 | * But the css returned by this routine can be "not populated yet" or "being |
769 | * destroyed". The caller should check css and cgroup's status. | |
770 | */ | |
771 | ||
772 | /* | |
773 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
774 | * cgroup_subsys_state. | |
775 | */ | |
776 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
777 | ||
778 | /* Find a cgroup_subsys_state which has given ID */ | |
779 | ||
780 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
781 | ||
782 | /* | |
783 | * Get a cgroup whose id is greater than or equal to id under tree of root. | |
784 | * Returning a cgroup_subsys_state or NULL. | |
785 | */ | |
786 | struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, | |
787 | struct cgroup_subsys_state *root, int *foundid); | |
788 | ||
789 | /* Returns true if root is ancestor of cg */ | |
790 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 791 | const struct cgroup_subsys_state *root); |
38460b48 KH |
792 | |
793 | /* Get id and depth of css */ | |
794 | unsigned short css_id(struct cgroup_subsys_state *css); | |
795 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
e5d1367f | 796 | struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); |
38460b48 | 797 | |
ddbcc7e8 PM |
798 | #else /* !CONFIG_CGROUPS */ |
799 | ||
800 | static inline int cgroup_init_early(void) { return 0; } | |
801 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 802 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 803 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 804 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
805 | |
806 | static inline void cgroup_lock(void) {} | |
807 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
808 | static inline int cgroupstats_build(struct cgroupstats *stats, |
809 | struct dentry *dentry) | |
810 | { | |
811 | return -EINVAL; | |
812 | } | |
ddbcc7e8 | 813 | |
d7926ee3 | 814 | /* No cgroups - nothing to do */ |
31583bb0 MT |
815 | static inline int cgroup_attach_task_all(struct task_struct *from, |
816 | struct task_struct *t) | |
817 | { | |
818 | return 0; | |
819 | } | |
d7926ee3 | 820 | |
ddbcc7e8 PM |
821 | #endif /* !CONFIG_CGROUPS */ |
822 | ||
823 | #endif /* _LINUX_CGROUP_H */ |