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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; |
a27bb332 | 31 | struct eventfd_ctx; |
ddbcc7e8 PM |
32 | |
33 | extern int cgroup_init_early(void); | |
34 | extern int cgroup_init(void); | |
b4f48b63 | 35 | extern void cgroup_fork(struct task_struct *p); |
817929ec | 36 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 37 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
38 | extern int cgroupstats_build(struct cgroupstats *stats, |
39 | struct dentry *dentry); | |
e6a1105b | 40 | extern int cgroup_load_subsys(struct cgroup_subsys *ss); |
cf5d5941 | 41 | extern void cgroup_unload_subsys(struct cgroup_subsys *ss); |
ddbcc7e8 | 42 | |
8d8b97ba | 43 | extern int proc_cgroup_show(struct seq_file *, void *); |
a424316c | 44 | |
7d8e0bf5 LZ |
45 | /* |
46 | * Define the enumeration of all cgroup subsystems. | |
47 | * | |
48 | * We define ids for builtin subsystems and then modular ones. | |
49 | */ | |
817929ec PM |
50 | #define SUBSYS(_x) _x ## _subsys_id, |
51 | enum cgroup_subsys_id { | |
7d8e0bf5 | 52 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
817929ec | 53 | #include <linux/cgroup_subsys.h> |
7d8e0bf5 LZ |
54 | #undef IS_SUBSYS_ENABLED |
55 | CGROUP_BUILTIN_SUBSYS_COUNT, | |
56 | ||
57 | __CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1, | |
58 | ||
59 | #define IS_SUBSYS_ENABLED(option) IS_MODULE(option) | |
817929ec | 60 | #include <linux/cgroup_subsys.h> |
7d8e0bf5 | 61 | #undef IS_SUBSYS_ENABLED |
a6f00298 | 62 | CGROUP_SUBSYS_COUNT, |
817929ec PM |
63 | }; |
64 | #undef SUBSYS | |
65 | ||
ddbcc7e8 PM |
66 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
67 | struct cgroup_subsys_state { | |
d20a390a PM |
68 | /* |
69 | * The cgroup that this subsystem is attached to. Useful | |
ddbcc7e8 | 70 | * for subsystems that want to know about the cgroup |
d20a390a PM |
71 | * hierarchy structure |
72 | */ | |
ddbcc7e8 PM |
73 | struct cgroup *cgroup; |
74 | ||
d20a390a PM |
75 | /* |
76 | * State maintained by the cgroup system to allow subsystems | |
e7c5ec91 | 77 | * to be "busy". Should be accessed via css_get(), |
d0b2fdd2 | 78 | * css_tryget() and css_put(). |
d20a390a | 79 | */ |
ddbcc7e8 PM |
80 | |
81 | atomic_t refcnt; | |
82 | ||
83 | unsigned long flags; | |
38460b48 | 84 | /* ID for this css, if possible */ |
2c392b8c | 85 | struct css_id __rcu *id; |
48ddbe19 TH |
86 | |
87 | /* Used to put @cgroup->dentry on the last css_put() */ | |
88 | struct work_struct dput_work; | |
ddbcc7e8 PM |
89 | }; |
90 | ||
91 | /* bits in struct cgroup_subsys_state flags field */ | |
92 | enum { | |
38b53aba | 93 | CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */ |
92fb9748 | 94 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
ddbcc7e8 PM |
95 | }; |
96 | ||
d7b9fff7 DN |
97 | /* Caller must verify that the css is not for root cgroup */ |
98 | static inline void __css_get(struct cgroup_subsys_state *css, int count) | |
99 | { | |
100 | atomic_add(count, &css->refcnt); | |
101 | } | |
102 | ||
ddbcc7e8 | 103 | /* |
e7c5ec91 PM |
104 | * Call css_get() to hold a reference on the css; it can be used |
105 | * for a reference obtained via: | |
106 | * - an existing ref-counted reference to the css | |
107 | * - task->cgroups for a locked task | |
ddbcc7e8 PM |
108 | */ |
109 | ||
110 | static inline void css_get(struct cgroup_subsys_state *css) | |
111 | { | |
112 | /* We don't need to reference count the root state */ | |
38b53aba | 113 | if (!(css->flags & CSS_ROOT)) |
d7b9fff7 | 114 | __css_get(css, 1); |
ddbcc7e8 | 115 | } |
e7c5ec91 | 116 | |
e7c5ec91 PM |
117 | /* |
118 | * Call css_tryget() to take a reference on a css if your existing | |
119 | * (known-valid) reference isn't already ref-counted. Returns false if | |
120 | * the css has been destroyed. | |
121 | */ | |
122 | ||
28b4c27b | 123 | extern bool __css_tryget(struct cgroup_subsys_state *css); |
e7c5ec91 PM |
124 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
125 | { | |
38b53aba | 126 | if (css->flags & CSS_ROOT) |
e7c5ec91 | 127 | return true; |
28b4c27b | 128 | return __css_tryget(css); |
e7c5ec91 PM |
129 | } |
130 | ||
ddbcc7e8 PM |
131 | /* |
132 | * css_put() should be called to release a reference taken by | |
e7c5ec91 | 133 | * css_get() or css_tryget() |
ddbcc7e8 PM |
134 | */ |
135 | ||
28b4c27b | 136 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
137 | static inline void css_put(struct cgroup_subsys_state *css) |
138 | { | |
38b53aba | 139 | if (!(css->flags & CSS_ROOT)) |
28b4c27b | 140 | __css_put(css); |
ddbcc7e8 PM |
141 | } |
142 | ||
3116f0e3 PM |
143 | /* bits in struct cgroup flags field */ |
144 | enum { | |
145 | /* Control Group is dead */ | |
146 | CGRP_REMOVED, | |
d20a390a PM |
147 | /* |
148 | * Control Group has previously had a child cgroup or a task, | |
149 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
150 | */ | |
3116f0e3 PM |
151 | CGRP_RELEASABLE, |
152 | /* Control Group requires release notifications to userspace */ | |
153 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d | 154 | /* |
2260e7fc TH |
155 | * Clone the parent's configuration when creating a new child |
156 | * cpuset cgroup. For historical reasons, this option can be | |
157 | * specified at mount time and thus is implemented here. | |
97978e6d | 158 | */ |
2260e7fc | 159 | CGRP_CPUSET_CLONE_CHILDREN, |
873fe09e TH |
160 | /* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */ |
161 | CGRP_SANE_BEHAVIOR, | |
3116f0e3 PM |
162 | }; |
163 | ||
65dff759 LZ |
164 | struct cgroup_name { |
165 | struct rcu_head rcu_head; | |
166 | char name[]; | |
3116f0e3 PM |
167 | }; |
168 | ||
ddbcc7e8 PM |
169 | struct cgroup { |
170 | unsigned long flags; /* "unsigned long" so bitops work */ | |
171 | ||
d20a390a PM |
172 | /* |
173 | * count users of this cgroup. >0 means busy, but doesn't | |
174 | * necessarily indicate the number of tasks in the cgroup | |
175 | */ | |
ddbcc7e8 PM |
176 | atomic_t count; |
177 | ||
0a950f65 TH |
178 | int id; /* ida allocated in-hierarchy ID */ |
179 | ||
ddbcc7e8 PM |
180 | /* |
181 | * We link our 'sibling' struct into our parent's 'children'. | |
182 | * Our children link their 'sibling' into our 'children'. | |
183 | */ | |
184 | struct list_head sibling; /* my parent's children */ | |
185 | struct list_head children; /* my children */ | |
05ef1d7c | 186 | struct list_head files; /* my files */ |
ddbcc7e8 | 187 | |
d20a390a | 188 | struct cgroup *parent; /* my parent */ |
febfcef6 | 189 | struct dentry *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 | 190 | |
65dff759 LZ |
191 | /* |
192 | * This is a copy of dentry->d_name, and it's needed because | |
193 | * we can't use dentry->d_name in cgroup_path(). | |
194 | * | |
195 | * You must acquire rcu_read_lock() to access cgrp->name, and | |
196 | * the only place that can change it is rename(), which is | |
197 | * protected by parent dir's i_mutex. | |
198 | * | |
199 | * Normally you should use cgroup_name() wrapper rather than | |
200 | * access it directly. | |
201 | */ | |
202 | struct cgroup_name __rcu *name; | |
203 | ||
ddbcc7e8 PM |
204 | /* Private pointers for each registered subsystem */ |
205 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
206 | ||
207 | struct cgroupfs_root *root; | |
817929ec PM |
208 | |
209 | /* | |
210 | * List of cg_cgroup_links pointing at css_sets with | |
211 | * tasks in this cgroup. Protected by css_set_lock | |
212 | */ | |
213 | struct list_head css_sets; | |
81a6a5cd | 214 | |
b0ca5a84 | 215 | struct list_head allcg_node; /* cgroupfs_root->allcg_list */ |
8e3f6541 | 216 | struct list_head cft_q_node; /* used during cftype add/rm */ |
b0ca5a84 | 217 | |
81a6a5cd PM |
218 | /* |
219 | * Linked list running through all cgroups that can | |
220 | * potentially be reaped by the release agent. Protected by | |
221 | * release_list_lock | |
222 | */ | |
223 | struct list_head release_list; | |
cc31edce | 224 | |
72a8cb30 BB |
225 | /* |
226 | * list of pidlists, up to two for each namespace (one for procs, one | |
227 | * for tasks); created on demand. | |
228 | */ | |
229 | struct list_head pidlists; | |
230 | struct mutex pidlist_mutex; | |
a47295e6 PM |
231 | |
232 | /* For RCU-protected deletion */ | |
233 | struct rcu_head rcu_head; | |
be445626 | 234 | struct work_struct free_work; |
0dea1168 | 235 | |
25985edc | 236 | /* List of events which userspace want to receive */ |
0dea1168 KS |
237 | struct list_head event_list; |
238 | spinlock_t event_list_lock; | |
03b1cde6 AR |
239 | |
240 | /* directory xattrs */ | |
241 | struct simple_xattrs xattrs; | |
817929ec PM |
242 | }; |
243 | ||
25a7e684 TH |
244 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
245 | ||
246 | /* cgroupfs_root->flags */ | |
247 | enum { | |
873fe09e TH |
248 | /* |
249 | * Unfortunately, cgroup core and various controllers are riddled | |
250 | * with idiosyncrasies and pointless options. The following flag, | |
251 | * when set, will force sane behavior - some options are forced on, | |
252 | * others are disallowed, and some controllers will change their | |
253 | * hierarchical or other behaviors. | |
254 | * | |
255 | * The set of behaviors affected by this flag are still being | |
256 | * determined and developed and the mount option for this flag is | |
257 | * prefixed with __DEVEL__. The prefix will be dropped once we | |
258 | * reach the point where all behaviors are compatible with the | |
259 | * planned unified hierarchy, which will automatically turn on this | |
260 | * flag. | |
261 | * | |
262 | * The followings are the behaviors currently affected this flag. | |
263 | * | |
264 | * - Mount options "noprefix" and "clone_children" are disallowed. | |
265 | * Also, cgroupfs file cgroup.clone_children is not created. | |
266 | * | |
267 | * - When mounting an existing superblock, mount options should | |
268 | * match. | |
269 | * | |
270 | * - Remount is disallowed. | |
271 | * | |
f00baae7 TH |
272 | * - memcg: use_hierarchy is on by default and the cgroup file for |
273 | * the flag is not created. | |
274 | * | |
873fe09e TH |
275 | * The followings are planned changes. |
276 | * | |
277 | * - release_agent will be disallowed once replacement notification | |
278 | * mechanism is implemented. | |
279 | */ | |
280 | CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), | |
281 | ||
25a7e684 TH |
282 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
283 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
284 | }; | |
285 | ||
286 | /* | |
287 | * A cgroupfs_root represents the root of a cgroup hierarchy, and may be | |
288 | * associated with a superblock to form an active hierarchy. This is | |
289 | * internal to cgroup core. Don't access directly from controllers. | |
290 | */ | |
291 | struct cgroupfs_root { | |
292 | struct super_block *sb; | |
293 | ||
294 | /* | |
295 | * The bitmask of subsystems intended to be attached to this | |
296 | * hierarchy | |
297 | */ | |
298 | unsigned long subsys_mask; | |
299 | ||
300 | /* Unique id for this hierarchy. */ | |
301 | int hierarchy_id; | |
302 | ||
303 | /* The bitmask of subsystems currently attached to this hierarchy */ | |
304 | unsigned long actual_subsys_mask; | |
305 | ||
306 | /* A list running through the attached subsystems */ | |
307 | struct list_head subsys_list; | |
308 | ||
309 | /* The root cgroup for this hierarchy */ | |
310 | struct cgroup top_cgroup; | |
311 | ||
312 | /* Tracks how many cgroups are currently defined in hierarchy.*/ | |
313 | int number_of_cgroups; | |
314 | ||
315 | /* A list running through the active hierarchies */ | |
316 | struct list_head root_list; | |
317 | ||
318 | /* All cgroups on this root, cgroup_mutex protected */ | |
319 | struct list_head allcg_list; | |
320 | ||
321 | /* Hierarchy-specific flags */ | |
322 | unsigned long flags; | |
323 | ||
324 | /* IDs for cgroups in this hierarchy */ | |
325 | struct ida cgroup_ida; | |
326 | ||
327 | /* The path to use for release notifications. */ | |
328 | char release_agent_path[PATH_MAX]; | |
329 | ||
330 | /* The name for this hierarchy - may be empty */ | |
331 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
332 | }; | |
333 | ||
d20a390a PM |
334 | /* |
335 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
336 | * cgroup_subsys_state objects. This saves space in the task struct |
337 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
338 | * list_add()/del() can bump the reference count on the entire cgroup |
339 | * set for a task. | |
817929ec PM |
340 | */ |
341 | ||
342 | struct css_set { | |
343 | ||
344 | /* Reference count */ | |
146aa1bd | 345 | atomic_t refcount; |
817929ec | 346 | |
472b1053 LZ |
347 | /* |
348 | * List running through all cgroup groups in the same hash | |
349 | * slot. Protected by css_set_lock | |
350 | */ | |
351 | struct hlist_node hlist; | |
352 | ||
817929ec PM |
353 | /* |
354 | * List running through all tasks using this cgroup | |
355 | * group. Protected by css_set_lock | |
356 | */ | |
357 | struct list_head tasks; | |
358 | ||
359 | /* | |
360 | * List of cg_cgroup_link objects on link chains from | |
361 | * cgroups referenced from this css_set. Protected by | |
362 | * css_set_lock | |
363 | */ | |
364 | struct list_head cg_links; | |
365 | ||
366 | /* | |
367 | * Set of subsystem states, one for each subsystem. This array | |
368 | * is immutable after creation apart from the init_css_set | |
cf5d5941 BB |
369 | * during subsystem registration (at boot time) and modular subsystem |
370 | * loading/unloading. | |
817929ec PM |
371 | */ |
372 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
373 | |
374 | /* For RCU-protected deletion */ | |
375 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
376 | }; |
377 | ||
91796569 PM |
378 | /* |
379 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
380 | * control files | |
381 | */ | |
382 | ||
383 | struct cgroup_map_cb { | |
384 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
385 | void *state; | |
386 | }; | |
387 | ||
d20a390a PM |
388 | /* |
389 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
390 | * |
391 | * When reading/writing to a file: | |
a043e3b2 | 392 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
393 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
394 | */ | |
395 | ||
8e3f6541 TH |
396 | /* cftype->flags */ |
397 | #define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */ | |
d0b2fdd2 | 398 | #define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create on root cg */ |
873fe09e | 399 | #define CFTYPE_INSANE (1U << 2) /* don't create if sane_behavior */ |
8e3f6541 TH |
400 | |
401 | #define MAX_CFTYPE_NAME 64 | |
402 | ||
ddbcc7e8 | 403 | struct cftype { |
d20a390a PM |
404 | /* |
405 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
406 | * subsystem, followed by a period. Zero length string indicates |
407 | * end of cftype array. | |
d20a390a | 408 | */ |
ddbcc7e8 PM |
409 | char name[MAX_CFTYPE_NAME]; |
410 | int private; | |
099fca32 LZ |
411 | /* |
412 | * If not 0, file mode is set to this value, otherwise it will | |
413 | * be figured out automatically | |
414 | */ | |
a5e7ed32 | 415 | umode_t mode; |
db3b1497 PM |
416 | |
417 | /* | |
418 | * If non-zero, defines the maximum length of string that can | |
419 | * be passed to write_string; defaults to 64 | |
420 | */ | |
421 | size_t max_write_len; | |
422 | ||
8e3f6541 TH |
423 | /* CFTYPE_* flags */ |
424 | unsigned int flags; | |
425 | ||
ce16b49d PM |
426 | int (*open)(struct inode *inode, struct file *file); |
427 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
428 | struct file *file, | |
429 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 430 | /* |
f4c753b7 | 431 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
432 | * single integer. Use it in place of read() |
433 | */ | |
ce16b49d | 434 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
435 | /* |
436 | * read_s64() is a signed version of read_u64() | |
437 | */ | |
ce16b49d | 438 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
439 | /* |
440 | * read_map() is used for defining a map of key/value | |
441 | * pairs. It should call cb->fill(cb, key, value) for each | |
442 | * entry. The key/value pairs (and their ordering) should not | |
443 | * change between reboots. | |
444 | */ | |
ce16b49d PM |
445 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
446 | struct cgroup_map_cb *cb); | |
29486df3 SH |
447 | /* |
448 | * read_seq_string() is used for outputting a simple sequence | |
449 | * using seqfile. | |
450 | */ | |
ce16b49d PM |
451 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
452 | struct seq_file *m); | |
91796569 | 453 | |
ce16b49d PM |
454 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
455 | struct file *file, | |
456 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
457 | |
458 | /* | |
f4c753b7 | 459 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
460 | * a single integer (as parsed by simple_strtoull) from |
461 | * userspace. Use in place of write(); return 0 or error. | |
462 | */ | |
ce16b49d | 463 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
464 | /* |
465 | * write_s64() is a signed version of write_u64() | |
466 | */ | |
ce16b49d | 467 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 468 | |
db3b1497 PM |
469 | /* |
470 | * write_string() is passed a nul-terminated kernelspace | |
471 | * buffer of maximum length determined by max_write_len. | |
472 | * Returns 0 or -ve error code. | |
473 | */ | |
474 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
475 | const char *buffer); | |
d447ea2f PE |
476 | /* |
477 | * trigger() callback can be used to get some kick from the | |
478 | * userspace, when the actual string written is not important | |
479 | * at all. The private field can be used to determine the | |
480 | * kick type for multiplexing. | |
481 | */ | |
482 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
483 | ||
ce16b49d | 484 | int (*release)(struct inode *inode, struct file *file); |
0dea1168 KS |
485 | |
486 | /* | |
487 | * register_event() callback will be used to add new userspace | |
488 | * waiter for changes related to the cftype. Implement it if | |
489 | * you want to provide this functionality. Use eventfd_signal() | |
490 | * on eventfd to send notification to userspace. | |
491 | */ | |
492 | int (*register_event)(struct cgroup *cgrp, struct cftype *cft, | |
493 | struct eventfd_ctx *eventfd, const char *args); | |
494 | /* | |
495 | * unregister_event() callback will be called when userspace | |
496 | * closes the eventfd or on cgroup removing. | |
497 | * This callback must be implemented, if you want provide | |
498 | * notification functionality. | |
0dea1168 | 499 | */ |
907860ed | 500 | void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
0dea1168 | 501 | struct eventfd_ctx *eventfd); |
ddbcc7e8 PM |
502 | }; |
503 | ||
8e3f6541 TH |
504 | /* |
505 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
506 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
507 | * terminated by zero length name. | |
508 | */ | |
509 | struct cftype_set { | |
510 | struct list_head node; /* chained at subsys->cftsets */ | |
03b1cde6 | 511 | struct cftype *cfts; |
8e3f6541 TH |
512 | }; |
513 | ||
31a7df01 CW |
514 | struct cgroup_scanner { |
515 | struct cgroup *cg; | |
516 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
517 | void (*process_task)(struct task_struct *p, | |
518 | struct cgroup_scanner *scan); | |
519 | struct ptr_heap *heap; | |
bd1a8ab7 | 520 | void *data; |
31a7df01 CW |
521 | }; |
522 | ||
873fe09e TH |
523 | /* |
524 | * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This | |
525 | * function can be called as long as @cgrp is accessible. | |
526 | */ | |
527 | static inline bool cgroup_sane_behavior(const struct cgroup *cgrp) | |
528 | { | |
529 | return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR; | |
530 | } | |
531 | ||
65dff759 LZ |
532 | /* Caller should hold rcu_read_lock() */ |
533 | static inline const char *cgroup_name(const struct cgroup *cgrp) | |
534 | { | |
535 | return rcu_dereference(cgrp->name)->name; | |
536 | } | |
537 | ||
03b1cde6 AR |
538 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
539 | int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
8e3f6541 | 540 | |
ffd2d883 | 541 | int cgroup_is_removed(const struct cgroup *cgrp); |
78574cf9 | 542 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
ddbcc7e8 | 543 | |
ffd2d883 | 544 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 545 | |
ffd2d883 | 546 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 547 | |
2f7ee569 TH |
548 | /* |
549 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
550 | * methods. | |
551 | */ | |
552 | struct cgroup_taskset; | |
553 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
554 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
555 | struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset); | |
556 | int cgroup_taskset_size(struct cgroup_taskset *tset); | |
557 | ||
558 | /** | |
559 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
560 | * @task: the loop cursor | |
561 | * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all | |
562 | * @tset: taskset to iterate | |
563 | */ | |
564 | #define cgroup_taskset_for_each(task, skip_cgrp, tset) \ | |
565 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
566 | (task) = cgroup_taskset_next((tset))) \ | |
567 | if (!(skip_cgrp) || \ | |
568 | cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp)) | |
569 | ||
21acb9ca TLSC |
570 | /* |
571 | * Control Group subsystem type. | |
572 | * See Documentation/cgroups/cgroups.txt for details | |
573 | */ | |
ddbcc7e8 PM |
574 | |
575 | struct cgroup_subsys { | |
92fb9748 TH |
576 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup *cgrp); |
577 | int (*css_online)(struct cgroup *cgrp); | |
578 | void (*css_offline)(struct cgroup *cgrp); | |
579 | void (*css_free)(struct cgroup *cgrp); | |
580 | ||
761b3ef5 LZ |
581 | int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); |
582 | void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
583 | void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset); | |
584 | void (*fork)(struct task_struct *task); | |
585 | void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp, | |
586 | struct task_struct *task); | |
761b3ef5 | 587 | void (*bind)(struct cgroup *root); |
e5991371 | 588 | |
ddbcc7e8 | 589 | int subsys_id; |
8bab8dde | 590 | int disabled; |
ddbcc7e8 | 591 | int early_init; |
38460b48 KH |
592 | /* |
593 | * True if this subsys uses ID. ID is not available before cgroup_init() | |
594 | * (not available in early_init time.) | |
595 | */ | |
596 | bool use_id; | |
48ddbe19 | 597 | |
8c7f6edb TH |
598 | /* |
599 | * If %false, this subsystem is properly hierarchical - | |
600 | * configuration, resource accounting and restriction on a parent | |
601 | * cgroup cover those of its children. If %true, hierarchy support | |
602 | * is broken in some ways - some subsystems ignore hierarchy | |
603 | * completely while others are only implemented half-way. | |
604 | * | |
605 | * It's now disallowed to create nested cgroups if the subsystem is | |
606 | * broken and cgroup core will emit a warning message on such | |
607 | * cases. Eventually, all subsystems will be made properly | |
608 | * hierarchical and this will go away. | |
609 | */ | |
610 | bool broken_hierarchy; | |
611 | bool warned_broken_hierarchy; | |
612 | ||
ddbcc7e8 PM |
613 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
614 | const char *name; | |
615 | ||
999cd8a4 PM |
616 | /* |
617 | * Link to parent, and list entry in parent's children. | |
6be96a5c | 618 | * Protected by cgroup_lock() |
999cd8a4 PM |
619 | */ |
620 | struct cgroupfs_root *root; | |
ddbcc7e8 | 621 | struct list_head sibling; |
38460b48 KH |
622 | /* used when use_id == true */ |
623 | struct idr idr; | |
42aee6c4 | 624 | spinlock_t id_lock; |
e6a1105b | 625 | |
8e3f6541 TH |
626 | /* list of cftype_sets */ |
627 | struct list_head cftsets; | |
628 | ||
629 | /* base cftypes, automatically [de]registered with subsys itself */ | |
630 | struct cftype *base_cftypes; | |
631 | struct cftype_set base_cftset; | |
632 | ||
e6a1105b BB |
633 | /* should be defined only by modular subsystems */ |
634 | struct module *module; | |
ddbcc7e8 PM |
635 | }; |
636 | ||
637 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
5fc0b025 | 638 | #define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option) |
ddbcc7e8 | 639 | #include <linux/cgroup_subsys.h> |
5fc0b025 | 640 | #undef IS_SUBSYS_ENABLED |
ddbcc7e8 PM |
641 | #undef SUBSYS |
642 | ||
643 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 644 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 645 | { |
ffd2d883 | 646 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
647 | } |
648 | ||
dc61b1d6 PZ |
649 | /* |
650 | * function to get the cgroup_subsys_state which allows for extra | |
651 | * rcu_dereference_check() conditions, such as locks used during the | |
652 | * cgroup_subsys::attach() methods. | |
653 | */ | |
2219449a TH |
654 | #ifdef CONFIG_PROVE_RCU |
655 | extern struct mutex cgroup_mutex; | |
dc61b1d6 | 656 | #define task_subsys_state_check(task, subsys_id, __c) \ |
2219449a TH |
657 | rcu_dereference_check((task)->cgroups->subsys[(subsys_id)], \ |
658 | lockdep_is_held(&(task)->alloc_lock) || \ | |
659 | lockdep_is_held(&cgroup_mutex) || (__c)) | |
660 | #else | |
dc61b1d6 | 661 | #define task_subsys_state_check(task, subsys_id, __c) \ |
2219449a TH |
662 | rcu_dereference((task)->cgroups->subsys[(subsys_id)]) |
663 | #endif | |
dc61b1d6 PZ |
664 | |
665 | static inline struct cgroup_subsys_state * | |
666 | task_subsys_state(struct task_struct *task, int subsys_id) | |
ddbcc7e8 | 667 | { |
dc61b1d6 | 668 | return task_subsys_state_check(task, subsys_id, false); |
ddbcc7e8 PM |
669 | } |
670 | ||
671 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
672 | int subsys_id) | |
673 | { | |
674 | return task_subsys_state(task, subsys_id)->cgroup; | |
675 | } | |
676 | ||
574bd9f7 TH |
677 | /** |
678 | * cgroup_for_each_child - iterate through children of a cgroup | |
679 | * @pos: the cgroup * to use as the loop cursor | |
680 | * @cgroup: cgroup whose children to walk | |
681 | * | |
682 | * Walk @cgroup's children. Must be called under rcu_read_lock(). A child | |
92fb9748 TH |
683 | * cgroup which hasn't finished ->css_online() or already has finished |
684 | * ->css_offline() may show up during traversal and it's each subsystem's | |
574bd9f7 TH |
685 | * responsibility to verify that each @pos is alive. |
686 | * | |
92fb9748 TH |
687 | * If a subsystem synchronizes against the parent in its ->css_online() and |
688 | * before starting iterating, a cgroup which finished ->css_online() is | |
689 | * guaranteed to be visible in the future iterations. | |
574bd9f7 TH |
690 | */ |
691 | #define cgroup_for_each_child(pos, cgroup) \ | |
692 | list_for_each_entry_rcu(pos, &(cgroup)->children, sibling) | |
693 | ||
694 | struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos, | |
695 | struct cgroup *cgroup); | |
12a9d2fe | 696 | struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos); |
574bd9f7 TH |
697 | |
698 | /** | |
699 | * cgroup_for_each_descendant_pre - pre-order walk of a cgroup's descendants | |
700 | * @pos: the cgroup * to use as the loop cursor | |
701 | * @cgroup: cgroup whose descendants to walk | |
702 | * | |
703 | * Walk @cgroup's descendants. Must be called under rcu_read_lock(). A | |
92fb9748 TH |
704 | * descendant cgroup which hasn't finished ->css_online() or already has |
705 | * finished ->css_offline() may show up during traversal and it's each | |
574bd9f7 TH |
706 | * subsystem's responsibility to verify that each @pos is alive. |
707 | * | |
92fb9748 TH |
708 | * If a subsystem synchronizes against the parent in its ->css_online() and |
709 | * before starting iterating, and synchronizes against @pos on each | |
7805d000 | 710 | * iteration, any descendant cgroup which finished ->css_online() is |
574bd9f7 TH |
711 | * guaranteed to be visible in the future iterations. |
712 | * | |
713 | * In other words, the following guarantees that a descendant can't escape | |
714 | * state updates of its ancestors. | |
715 | * | |
92fb9748 | 716 | * my_online(@cgrp) |
574bd9f7 TH |
717 | * { |
718 | * Lock @cgrp->parent and @cgrp; | |
719 | * Inherit state from @cgrp->parent; | |
720 | * Unlock both. | |
721 | * } | |
722 | * | |
723 | * my_update_state(@cgrp) | |
724 | * { | |
725 | * Lock @cgrp; | |
726 | * Update @cgrp's state; | |
727 | * Unlock @cgrp; | |
728 | * | |
729 | * cgroup_for_each_descendant_pre(@pos, @cgrp) { | |
730 | * Lock @pos; | |
731 | * Verify @pos is alive and inherit state from @pos->parent; | |
732 | * Unlock @pos; | |
733 | * } | |
734 | * } | |
735 | * | |
736 | * As long as the inheriting step, including checking the parent state, is | |
737 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
738 | * while inheriting. The state update to the parent is guaranteed to be | |
739 | * visible by walking order and, as long as inheriting operations to the | |
740 | * same @pos are atomic to each other, multiple updates racing each other | |
741 | * still result in the correct state. It's guaranateed that at least one | |
742 | * inheritance happens for any cgroup after the latest update to its | |
743 | * parent. | |
744 | * | |
745 | * If checking parent's state requires locking the parent, each inheriting | |
746 | * iteration should lock and unlock both @pos->parent and @pos. | |
747 | * | |
748 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 749 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 TH |
750 | * operations. |
751 | */ | |
752 | #define cgroup_for_each_descendant_pre(pos, cgroup) \ | |
753 | for (pos = cgroup_next_descendant_pre(NULL, (cgroup)); (pos); \ | |
754 | pos = cgroup_next_descendant_pre((pos), (cgroup))) | |
755 | ||
756 | struct cgroup *cgroup_next_descendant_post(struct cgroup *pos, | |
757 | struct cgroup *cgroup); | |
758 | ||
759 | /** | |
760 | * cgroup_for_each_descendant_post - post-order walk of a cgroup's descendants | |
761 | * @pos: the cgroup * to use as the loop cursor | |
762 | * @cgroup: cgroup whose descendants to walk | |
763 | * | |
764 | * Similar to cgroup_for_each_descendant_pre() but performs post-order | |
765 | * traversal instead. Note that the walk visibility guarantee described in | |
766 | * pre-order walk doesn't apply the same to post-order walks. | |
767 | */ | |
768 | #define cgroup_for_each_descendant_post(pos, cgroup) \ | |
769 | for (pos = cgroup_next_descendant_post(NULL, (cgroup)); (pos); \ | |
770 | pos = cgroup_next_descendant_post((pos), (cgroup))) | |
771 | ||
817929ec PM |
772 | /* A cgroup_iter should be treated as an opaque object */ |
773 | struct cgroup_iter { | |
774 | struct list_head *cg_link; | |
775 | struct list_head *task; | |
776 | }; | |
777 | ||
d20a390a PM |
778 | /* |
779 | * To iterate across the tasks in a cgroup: | |
817929ec | 780 | * |
b595076a | 781 | * 1) call cgroup_iter_start to initialize an iterator |
817929ec PM |
782 | * |
783 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
784 | * returns NULL or until you want to end the iteration | |
785 | * | |
786 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 | 787 | * |
d20a390a PM |
788 | * Or, call cgroup_scan_tasks() to iterate through every task in a |
789 | * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling | |
790 | * the test_task() callback, but not while calling the process_task() | |
791 | * callback. | |
817929ec | 792 | */ |
ffd2d883 LZ |
793 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
794 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 795 | struct cgroup_iter *it); |
ffd2d883 | 796 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 797 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
31583bb0 | 798 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 799 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 800 | |
38460b48 KH |
801 | /* |
802 | * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works | |
803 | * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. | |
804 | * CSS ID is assigned at cgroup allocation (create) automatically | |
805 | * and removed when subsys calls free_css_id() function. This is because | |
806 | * the lifetime of cgroup_subsys_state is subsys's matter. | |
807 | * | |
808 | * Looking up and scanning function should be called under rcu_read_lock(). | |
6be96a5c | 809 | * Taking cgroup_mutex is not necessary for following calls. |
38460b48 KH |
810 | * But the css returned by this routine can be "not populated yet" or "being |
811 | * destroyed". The caller should check css and cgroup's status. | |
812 | */ | |
813 | ||
814 | /* | |
815 | * Typically Called at ->destroy(), or somewhere the subsys frees | |
816 | * cgroup_subsys_state. | |
817 | */ | |
818 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); | |
819 | ||
820 | /* Find a cgroup_subsys_state which has given ID */ | |
821 | ||
822 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); | |
823 | ||
38460b48 KH |
824 | /* Returns true if root is ancestor of cg */ |
825 | bool css_is_ancestor(struct cgroup_subsys_state *cg, | |
0b7f569e | 826 | const struct cgroup_subsys_state *root); |
38460b48 KH |
827 | |
828 | /* Get id and depth of css */ | |
829 | unsigned short css_id(struct cgroup_subsys_state *css); | |
830 | unsigned short css_depth(struct cgroup_subsys_state *css); | |
e5d1367f | 831 | struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id); |
38460b48 | 832 | |
ddbcc7e8 PM |
833 | #else /* !CONFIG_CGROUPS */ |
834 | ||
835 | static inline int cgroup_init_early(void) { return 0; } | |
836 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 837 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 838 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 839 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
840 | |
841 | static inline void cgroup_lock(void) {} | |
842 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
843 | static inline int cgroupstats_build(struct cgroupstats *stats, |
844 | struct dentry *dentry) | |
845 | { | |
846 | return -EINVAL; | |
847 | } | |
ddbcc7e8 | 848 | |
d7926ee3 | 849 | /* No cgroups - nothing to do */ |
31583bb0 MT |
850 | static inline int cgroup_attach_task_all(struct task_struct *from, |
851 | struct task_struct *t) | |
852 | { | |
853 | return 0; | |
854 | } | |
d7926ee3 | 855 | |
ddbcc7e8 PM |
856 | #endif /* !CONFIG_CGROUPS */ |
857 | ||
858 | #endif /* _LINUX_CGROUP_H */ |