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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> |
25a7e684 | 21 | #include <linux/fs.h> |
d3daf28d | 22 | #include <linux/percpu-refcount.h> |
7da11279 | 23 | #include <linux/seq_file.h> |
2bd59d48 | 24 | #include <linux/kernfs.h> |
ddbcc7e8 PM |
25 | |
26 | #ifdef CONFIG_CGROUPS | |
27 | ||
28 | struct cgroupfs_root; | |
29 | struct cgroup_subsys; | |
30 | struct inode; | |
84eea842 | 31 | struct cgroup; |
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); | |
ddbcc7e8 | 40 | |
8d8b97ba | 41 | extern int proc_cgroup_show(struct seq_file *, void *); |
a424316c | 42 | |
3ed80a62 | 43 | /* define the enumeration of all cgroup subsystems */ |
073219e9 | 44 | #define SUBSYS(_x) _x ## _cgrp_id, |
817929ec PM |
45 | enum cgroup_subsys_id { |
46 | #include <linux/cgroup_subsys.h> | |
a6f00298 | 47 | CGROUP_SUBSYS_COUNT, |
817929ec PM |
48 | }; |
49 | #undef SUBSYS | |
50 | ||
ddbcc7e8 PM |
51 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
52 | struct cgroup_subsys_state { | |
72c97e54 | 53 | /* the cgroup that this css is attached to */ |
ddbcc7e8 PM |
54 | struct cgroup *cgroup; |
55 | ||
72c97e54 TH |
56 | /* the cgroup subsystem that this css is attached to */ |
57 | struct cgroup_subsys *ss; | |
58 | ||
d3daf28d TH |
59 | /* reference count - access via css_[try]get() and css_put() */ |
60 | struct percpu_ref refcnt; | |
ddbcc7e8 | 61 | |
0ae78e0b TH |
62 | /* the parent css */ |
63 | struct cgroup_subsys_state *parent; | |
64 | ||
ddbcc7e8 | 65 | unsigned long flags; |
48ddbe19 | 66 | |
0c21ead1 TH |
67 | /* percpu_ref killing and RCU release */ |
68 | struct rcu_head rcu_head; | |
35ef10da | 69 | struct work_struct destroy_work; |
ddbcc7e8 PM |
70 | }; |
71 | ||
72 | /* bits in struct cgroup_subsys_state flags field */ | |
73 | enum { | |
38b53aba | 74 | CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */ |
92fb9748 | 75 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
ddbcc7e8 PM |
76 | }; |
77 | ||
5de0107e TH |
78 | /** |
79 | * css_get - obtain a reference on the specified css | |
80 | * @css: target css | |
81 | * | |
82 | * The caller must already have a reference. | |
ddbcc7e8 | 83 | */ |
ddbcc7e8 PM |
84 | static inline void css_get(struct cgroup_subsys_state *css) |
85 | { | |
86 | /* We don't need to reference count the root state */ | |
38b53aba | 87 | if (!(css->flags & CSS_ROOT)) |
d3daf28d | 88 | percpu_ref_get(&css->refcnt); |
ddbcc7e8 | 89 | } |
e7c5ec91 | 90 | |
5de0107e TH |
91 | /** |
92 | * css_tryget - try to obtain a reference on the specified css | |
93 | * @css: target css | |
94 | * | |
95 | * Obtain a reference on @css if it's alive. The caller naturally needs to | |
96 | * ensure that @css is accessible but doesn't have to be holding a | |
97 | * reference on it - IOW, RCU protected access is good enough for this | |
98 | * function. Returns %true if a reference count was successfully obtained; | |
99 | * %false otherwise. | |
100 | */ | |
e7c5ec91 PM |
101 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
102 | { | |
38b53aba | 103 | if (css->flags & CSS_ROOT) |
e7c5ec91 | 104 | return true; |
d3daf28d | 105 | return percpu_ref_tryget(&css->refcnt); |
e7c5ec91 PM |
106 | } |
107 | ||
5de0107e TH |
108 | /** |
109 | * css_put - put a css reference | |
110 | * @css: target css | |
111 | * | |
112 | * Put a reference obtained via css_get() and css_tryget(). | |
113 | */ | |
ddbcc7e8 PM |
114 | static inline void css_put(struct cgroup_subsys_state *css) |
115 | { | |
38b53aba | 116 | if (!(css->flags & CSS_ROOT)) |
d3daf28d | 117 | percpu_ref_put(&css->refcnt); |
ddbcc7e8 PM |
118 | } |
119 | ||
3116f0e3 PM |
120 | /* bits in struct cgroup flags field */ |
121 | enum { | |
122 | /* Control Group is dead */ | |
54766d4a | 123 | CGRP_DEAD, |
d20a390a PM |
124 | /* |
125 | * Control Group has previously had a child cgroup or a task, | |
126 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
127 | */ | |
3116f0e3 PM |
128 | CGRP_RELEASABLE, |
129 | /* Control Group requires release notifications to userspace */ | |
130 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d | 131 | /* |
2260e7fc TH |
132 | * Clone the parent's configuration when creating a new child |
133 | * cpuset cgroup. For historical reasons, this option can be | |
134 | * specified at mount time and thus is implemented here. | |
97978e6d | 135 | */ |
2260e7fc | 136 | CGRP_CPUSET_CLONE_CHILDREN, |
873fe09e TH |
137 | /* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */ |
138 | CGRP_SANE_BEHAVIOR, | |
3116f0e3 PM |
139 | }; |
140 | ||
ddbcc7e8 PM |
141 | struct cgroup { |
142 | unsigned long flags; /* "unsigned long" so bitops work */ | |
143 | ||
b414dc09 LZ |
144 | /* |
145 | * idr allocated in-hierarchy ID. | |
146 | * | |
147 | * The ID of the root cgroup is always 0, and a new cgroup | |
148 | * will be assigned with a smallest available ID. | |
0ab02ca8 LZ |
149 | * |
150 | * Allocating/Removing ID must be protected by cgroup_mutex. | |
b414dc09 LZ |
151 | */ |
152 | int id; | |
0a950f65 | 153 | |
f20104de TH |
154 | /* the number of attached css's */ |
155 | int nr_css; | |
156 | ||
2bd59d48 TH |
157 | atomic_t refcnt; |
158 | ||
ddbcc7e8 PM |
159 | /* |
160 | * We link our 'sibling' struct into our parent's 'children'. | |
161 | * Our children link their 'sibling' into our 'children'. | |
162 | */ | |
163 | struct list_head sibling; /* my parent's children */ | |
164 | struct list_head children; /* my children */ | |
165 | ||
d20a390a | 166 | struct cgroup *parent; /* my parent */ |
2bd59d48 | 167 | struct kernfs_node *kn; /* cgroup kernfs entry */ |
ddbcc7e8 | 168 | |
53fa5261 TH |
169 | /* |
170 | * Monotonically increasing unique serial number which defines a | |
171 | * uniform order among all cgroups. It's guaranteed that all | |
172 | * ->children lists are in the ascending order of ->serial_nr. | |
173 | * It's used to allow interrupting and resuming iterations. | |
174 | */ | |
175 | u64 serial_nr; | |
176 | ||
ddbcc7e8 | 177 | /* Private pointers for each registered subsystem */ |
73e80ed8 | 178 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; |
ddbcc7e8 PM |
179 | |
180 | struct cgroupfs_root *root; | |
817929ec PM |
181 | |
182 | /* | |
69d0206c TH |
183 | * List of cgrp_cset_links pointing at css_sets with tasks in this |
184 | * cgroup. Protected by css_set_lock. | |
817929ec | 185 | */ |
69d0206c | 186 | struct list_head cset_links; |
81a6a5cd PM |
187 | |
188 | /* | |
189 | * Linked list running through all cgroups that can | |
190 | * potentially be reaped by the release agent. Protected by | |
191 | * release_list_lock | |
192 | */ | |
193 | struct list_head release_list; | |
cc31edce | 194 | |
72a8cb30 BB |
195 | /* |
196 | * list of pidlists, up to two for each namespace (one for procs, one | |
197 | * for tasks); created on demand. | |
198 | */ | |
199 | struct list_head pidlists; | |
200 | struct mutex pidlist_mutex; | |
a47295e6 | 201 | |
67f4c36f TH |
202 | /* dummy css with NULL ->ss, points back to this cgroup */ |
203 | struct cgroup_subsys_state dummy_css; | |
204 | ||
d3daf28d | 205 | /* For css percpu_ref killing and RCU-protected deletion */ |
a47295e6 | 206 | struct rcu_head rcu_head; |
ea15f8cc | 207 | struct work_struct destroy_work; |
817929ec PM |
208 | }; |
209 | ||
25a7e684 TH |
210 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
211 | ||
212 | /* cgroupfs_root->flags */ | |
213 | enum { | |
873fe09e TH |
214 | /* |
215 | * Unfortunately, cgroup core and various controllers are riddled | |
216 | * with idiosyncrasies and pointless options. The following flag, | |
217 | * when set, will force sane behavior - some options are forced on, | |
218 | * others are disallowed, and some controllers will change their | |
219 | * hierarchical or other behaviors. | |
220 | * | |
221 | * The set of behaviors affected by this flag are still being | |
222 | * determined and developed and the mount option for this flag is | |
223 | * prefixed with __DEVEL__. The prefix will be dropped once we | |
224 | * reach the point where all behaviors are compatible with the | |
225 | * planned unified hierarchy, which will automatically turn on this | |
226 | * flag. | |
227 | * | |
228 | * The followings are the behaviors currently affected this flag. | |
229 | * | |
230 | * - Mount options "noprefix" and "clone_children" are disallowed. | |
231 | * Also, cgroupfs file cgroup.clone_children is not created. | |
232 | * | |
233 | * - When mounting an existing superblock, mount options should | |
234 | * match. | |
235 | * | |
236 | * - Remount is disallowed. | |
237 | * | |
0b0585c3 LT |
238 | * - rename(2) is disallowed. |
239 | * | |
f63674fd TH |
240 | * - "tasks" is removed. Everything should be at process |
241 | * granularity. Use "cgroup.procs" instead. | |
f00baae7 | 242 | * |
afb2bc14 TH |
243 | * - "cgroup.procs" is not sorted. pids will be unique unless they |
244 | * got recycled inbetween reads. | |
245 | * | |
f63674fd TH |
246 | * - "release_agent" and "notify_on_release" are removed. |
247 | * Replacement notification mechanism will be implemented. | |
873fe09e | 248 | * |
86bf4b68 TH |
249 | * - "xattr" mount option is deprecated. kernfs always enables it. |
250 | * | |
5c5cc623 LZ |
251 | * - cpuset: tasks will be kept in empty cpusets when hotplug happens |
252 | * and take masks of ancestors with non-empty cpus/mems, instead of | |
253 | * being moved to an ancestor. | |
254 | * | |
88fa523b LZ |
255 | * - cpuset: a task can be moved into an empty cpuset, and again it |
256 | * takes masks of ancestors. | |
6db8e85c | 257 | * |
f63674fd TH |
258 | * - memcg: use_hierarchy is on by default and the cgroup file for |
259 | * the flag is not created. | |
f00baae7 | 260 | * |
9138125b | 261 | * - blkcg: blk-throttle becomes properly hierarchical. |
873fe09e TH |
262 | */ |
263 | CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), | |
264 | ||
25a7e684 TH |
265 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
266 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
0ce6cba3 TH |
267 | |
268 | /* mount options live below bit 16 */ | |
269 | CGRP_ROOT_OPTION_MASK = (1 << 16) - 1, | |
270 | ||
271 | CGRP_ROOT_SUBSYS_BOUND = (1 << 16), /* subsystems finished binding */ | |
25a7e684 TH |
272 | }; |
273 | ||
274 | /* | |
275 | * A cgroupfs_root represents the root of a cgroup hierarchy, and may be | |
2bd59d48 | 276 | * associated with a kernfs_root to form an active hierarchy. This is |
25a7e684 TH |
277 | * internal to cgroup core. Don't access directly from controllers. |
278 | */ | |
279 | struct cgroupfs_root { | |
2bd59d48 | 280 | struct kernfs_root *kf_root; |
25a7e684 | 281 | |
a8a648c4 | 282 | /* The bitmask of subsystems attached to this hierarchy */ |
25a7e684 TH |
283 | unsigned long subsys_mask; |
284 | ||
285 | /* Unique id for this hierarchy. */ | |
286 | int hierarchy_id; | |
287 | ||
776f02fa | 288 | /* The root cgroup. Root is destroyed on its release. */ |
25a7e684 TH |
289 | struct cgroup top_cgroup; |
290 | ||
3c9c825b TH |
291 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
292 | atomic_t nr_cgrps; | |
25a7e684 TH |
293 | |
294 | /* A list running through the active hierarchies */ | |
295 | struct list_head root_list; | |
296 | ||
25a7e684 TH |
297 | /* Hierarchy-specific flags */ |
298 | unsigned long flags; | |
299 | ||
300 | /* IDs for cgroups in this hierarchy */ | |
4e96ee8e | 301 | struct idr cgroup_idr; |
25a7e684 TH |
302 | |
303 | /* The path to use for release notifications. */ | |
304 | char release_agent_path[PATH_MAX]; | |
305 | ||
306 | /* The name for this hierarchy - may be empty */ | |
307 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
308 | }; | |
309 | ||
d20a390a PM |
310 | /* |
311 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
312 | * cgroup_subsys_state objects. This saves space in the task struct |
313 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
314 | * list_add()/del() can bump the reference count on the entire cgroup |
315 | * set for a task. | |
817929ec PM |
316 | */ |
317 | ||
318 | struct css_set { | |
319 | ||
320 | /* Reference count */ | |
146aa1bd | 321 | atomic_t refcount; |
817929ec | 322 | |
472b1053 LZ |
323 | /* |
324 | * List running through all cgroup groups in the same hash | |
325 | * slot. Protected by css_set_lock | |
326 | */ | |
327 | struct hlist_node hlist; | |
328 | ||
817929ec PM |
329 | /* |
330 | * List running through all tasks using this cgroup | |
331 | * group. Protected by css_set_lock | |
332 | */ | |
333 | struct list_head tasks; | |
334 | ||
335 | /* | |
69d0206c TH |
336 | * List of cgrp_cset_links pointing at cgroups referenced from this |
337 | * css_set. Protected by css_set_lock. | |
817929ec | 338 | */ |
69d0206c | 339 | struct list_head cgrp_links; |
817929ec PM |
340 | |
341 | /* | |
3ed80a62 TH |
342 | * Set of subsystem states, one for each subsystem. This array is |
343 | * immutable after creation apart from the init_css_set during | |
344 | * subsystem registration (at boot time). | |
817929ec PM |
345 | */ |
346 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
347 | |
348 | /* For RCU-protected deletion */ | |
349 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
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 | 360 | /* cftype->flags */ |
02c402d9 | 361 | enum { |
6f4b7e63 LZ |
362 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ |
363 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
02c402d9 | 364 | CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */ |
9fa4db33 | 365 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
02c402d9 | 366 | }; |
8e3f6541 TH |
367 | |
368 | #define MAX_CFTYPE_NAME 64 | |
369 | ||
ddbcc7e8 | 370 | struct cftype { |
d20a390a PM |
371 | /* |
372 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
373 | * subsystem, followed by a period. Zero length string indicates |
374 | * end of cftype array. | |
d20a390a | 375 | */ |
ddbcc7e8 PM |
376 | char name[MAX_CFTYPE_NAME]; |
377 | int private; | |
099fca32 LZ |
378 | /* |
379 | * If not 0, file mode is set to this value, otherwise it will | |
380 | * be figured out automatically | |
381 | */ | |
a5e7ed32 | 382 | umode_t mode; |
db3b1497 PM |
383 | |
384 | /* | |
5f469907 TH |
385 | * The maximum length of string, excluding trailing nul, that can |
386 | * be passed to write_string. If < PAGE_SIZE-1, PAGE_SIZE-1 is | |
387 | * assumed. | |
db3b1497 PM |
388 | */ |
389 | size_t max_write_len; | |
390 | ||
8e3f6541 TH |
391 | /* CFTYPE_* flags */ |
392 | unsigned int flags; | |
393 | ||
2bb566cb | 394 | /* |
0adb0704 TH |
395 | * Fields used for internal bookkeeping. Initialized automatically |
396 | * during registration. | |
2bb566cb | 397 | */ |
0adb0704 TH |
398 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ |
399 | struct list_head node; /* anchored at ss->cfts */ | |
2bd59d48 TH |
400 | struct kernfs_ops *kf_ops; |
401 | ||
ddbcc7e8 | 402 | /* |
f4c753b7 | 403 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
404 | * single integer. Use it in place of read() |
405 | */ | |
182446d0 | 406 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); |
e73d2c61 PM |
407 | /* |
408 | * read_s64() is a signed version of read_u64() | |
409 | */ | |
182446d0 | 410 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); |
2da8ca82 TH |
411 | |
412 | /* generic seq_file read interface */ | |
413 | int (*seq_show)(struct seq_file *sf, void *v); | |
91796569 | 414 | |
6612f05b TH |
415 | /* optional ops, implement all or none */ |
416 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
417 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
418 | void (*seq_stop)(struct seq_file *sf, void *v); | |
419 | ||
355e0c48 | 420 | /* |
f4c753b7 | 421 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
422 | * a single integer (as parsed by simple_strtoull) from |
423 | * userspace. Use in place of write(); return 0 or error. | |
424 | */ | |
182446d0 TH |
425 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, |
426 | u64 val); | |
e73d2c61 PM |
427 | /* |
428 | * write_s64() is a signed version of write_u64() | |
429 | */ | |
182446d0 TH |
430 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, |
431 | s64 val); | |
355e0c48 | 432 | |
db3b1497 PM |
433 | /* |
434 | * write_string() is passed a nul-terminated kernelspace | |
435 | * buffer of maximum length determined by max_write_len. | |
436 | * Returns 0 or -ve error code. | |
437 | */ | |
182446d0 | 438 | int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft, |
db3b1497 | 439 | const char *buffer); |
d447ea2f PE |
440 | /* |
441 | * trigger() callback can be used to get some kick from the | |
442 | * userspace, when the actual string written is not important | |
443 | * at all. The private field can be used to determine the | |
444 | * kick type for multiplexing. | |
445 | */ | |
182446d0 | 446 | int (*trigger)(struct cgroup_subsys_state *css, unsigned int event); |
2bd59d48 TH |
447 | |
448 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
449 | struct lock_class_key lockdep_key; | |
450 | #endif | |
ddbcc7e8 PM |
451 | }; |
452 | ||
873fe09e TH |
453 | /* |
454 | * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This | |
455 | * function can be called as long as @cgrp is accessible. | |
456 | */ | |
457 | static inline bool cgroup_sane_behavior(const struct cgroup *cgrp) | |
458 | { | |
459 | return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR; | |
460 | } | |
461 | ||
b1664924 TH |
462 | /* returns ino associated with a cgroup, 0 indicates unmounted root */ |
463 | static inline ino_t cgroup_ino(struct cgroup *cgrp) | |
464 | { | |
2bd59d48 TH |
465 | if (cgrp->kn) |
466 | return cgrp->kn->ino; | |
b1664924 TH |
467 | else |
468 | return 0; | |
469 | } | |
470 | ||
7da11279 TH |
471 | static inline struct cftype *seq_cft(struct seq_file *seq) |
472 | { | |
2bd59d48 TH |
473 | struct kernfs_open_file *of = seq->private; |
474 | ||
475 | return of->kn->priv; | |
7da11279 TH |
476 | } |
477 | ||
59f5296b TH |
478 | struct cgroup_subsys_state *seq_css(struct seq_file *seq); |
479 | ||
e61734c5 TH |
480 | /* |
481 | * Name / path handling functions. All are thin wrappers around the kernfs | |
482 | * counterparts and can be called under any context. | |
483 | */ | |
484 | ||
485 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) | |
486 | { | |
487 | return kernfs_name(cgrp->kn, buf, buflen); | |
488 | } | |
489 | ||
490 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, | |
491 | size_t buflen) | |
492 | { | |
493 | return kernfs_path(cgrp->kn, buf, buflen); | |
494 | } | |
495 | ||
496 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) | |
497 | { | |
498 | /* dummy_top doesn't have a kn associated */ | |
499 | if (cgrp->kn) | |
500 | pr_cont_kernfs_name(cgrp->kn); | |
501 | else | |
502 | pr_cont("/"); | |
503 | } | |
504 | ||
505 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) | |
506 | { | |
507 | /* dummy_top doesn't have a kn associated */ | |
508 | if (cgrp->kn) | |
509 | pr_cont_kernfs_path(cgrp->kn); | |
510 | else | |
511 | pr_cont("/"); | |
512 | } | |
513 | ||
514 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); | |
515 | ||
03b1cde6 | 516 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
2bb566cb | 517 | int cgroup_rm_cftypes(struct cftype *cfts); |
8e3f6541 | 518 | |
78574cf9 | 519 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
ddbcc7e8 | 520 | |
ffd2d883 | 521 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 522 | |
2f7ee569 TH |
523 | /* |
524 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
525 | * methods. | |
526 | */ | |
527 | struct cgroup_taskset; | |
528 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
529 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
d99c8727 TH |
530 | struct cgroup_subsys_state *cgroup_taskset_cur_css(struct cgroup_taskset *tset, |
531 | int subsys_id); | |
2f7ee569 TH |
532 | int cgroup_taskset_size(struct cgroup_taskset *tset); |
533 | ||
534 | /** | |
535 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
536 | * @task: the loop cursor | |
d99c8727 | 537 | * @skip_css: skip if task's css matches this, %NULL to iterate through all |
2f7ee569 TH |
538 | * @tset: taskset to iterate |
539 | */ | |
d99c8727 | 540 | #define cgroup_taskset_for_each(task, skip_css, tset) \ |
2f7ee569 TH |
541 | for ((task) = cgroup_taskset_first((tset)); (task); \ |
542 | (task) = cgroup_taskset_next((tset))) \ | |
d99c8727 TH |
543 | if (!(skip_css) || \ |
544 | cgroup_taskset_cur_css((tset), \ | |
aec25020 | 545 | (skip_css)->ss->id) != (skip_css)) |
2f7ee569 | 546 | |
21acb9ca TLSC |
547 | /* |
548 | * Control Group subsystem type. | |
549 | * See Documentation/cgroups/cgroups.txt for details | |
550 | */ | |
ddbcc7e8 PM |
551 | |
552 | struct cgroup_subsys { | |
eb95419b TH |
553 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); |
554 | int (*css_online)(struct cgroup_subsys_state *css); | |
555 | void (*css_offline)(struct cgroup_subsys_state *css); | |
556 | void (*css_free)(struct cgroup_subsys_state *css); | |
557 | ||
558 | int (*can_attach)(struct cgroup_subsys_state *css, | |
559 | struct cgroup_taskset *tset); | |
560 | void (*cancel_attach)(struct cgroup_subsys_state *css, | |
561 | struct cgroup_taskset *tset); | |
562 | void (*attach)(struct cgroup_subsys_state *css, | |
563 | struct cgroup_taskset *tset); | |
761b3ef5 | 564 | void (*fork)(struct task_struct *task); |
eb95419b TH |
565 | void (*exit)(struct cgroup_subsys_state *css, |
566 | struct cgroup_subsys_state *old_css, | |
761b3ef5 | 567 | struct task_struct *task); |
eb95419b | 568 | void (*bind)(struct cgroup_subsys_state *root_css); |
e5991371 | 569 | |
8bab8dde | 570 | int disabled; |
ddbcc7e8 | 571 | int early_init; |
48ddbe19 | 572 | |
8c7f6edb TH |
573 | /* |
574 | * If %false, this subsystem is properly hierarchical - | |
575 | * configuration, resource accounting and restriction on a parent | |
576 | * cgroup cover those of its children. If %true, hierarchy support | |
577 | * is broken in some ways - some subsystems ignore hierarchy | |
578 | * completely while others are only implemented half-way. | |
579 | * | |
580 | * It's now disallowed to create nested cgroups if the subsystem is | |
581 | * broken and cgroup core will emit a warning message on such | |
582 | * cases. Eventually, all subsystems will be made properly | |
583 | * hierarchical and this will go away. | |
584 | */ | |
585 | bool broken_hierarchy; | |
586 | bool warned_broken_hierarchy; | |
587 | ||
073219e9 | 588 | /* the following two fields are initialized automtically during boot */ |
aec25020 | 589 | int id; |
ddbcc7e8 PM |
590 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
591 | const char *name; | |
592 | ||
b85d2040 | 593 | /* link to parent, protected by cgroup_lock() */ |
999cd8a4 | 594 | struct cgroupfs_root *root; |
e6a1105b | 595 | |
0adb0704 TH |
596 | /* |
597 | * List of cftypes. Each entry is the first entry of an array | |
598 | * terminated by zero length name. | |
599 | */ | |
600 | struct list_head cfts; | |
8e3f6541 | 601 | |
de00ffa5 | 602 | /* base cftypes, automatically registered with subsys itself */ |
8e3f6541 | 603 | struct cftype *base_cftypes; |
ddbcc7e8 PM |
604 | }; |
605 | ||
073219e9 | 606 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
ddbcc7e8 PM |
607 | #include <linux/cgroup_subsys.h> |
608 | #undef SUBSYS | |
609 | ||
63876986 TH |
610 | /** |
611 | * css_parent - find the parent css | |
612 | * @css: the target cgroup_subsys_state | |
613 | * | |
614 | * Return the parent css of @css. This function is guaranteed to return | |
615 | * non-NULL parent as long as @css isn't the root. | |
616 | */ | |
617 | static inline | |
618 | struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) | |
619 | { | |
0ae78e0b | 620 | return css->parent; |
63876986 TH |
621 | } |
622 | ||
14611e51 TH |
623 | /** |
624 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
625 | * @task: the task to obtain css_set for | |
626 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
627 | * | |
628 | * A task's css_set is RCU protected, initialized and exited while holding | |
629 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
630 | * and task_lock() while the task is alive. This macro verifies that the | |
631 | * caller is inside proper critical section and returns @task's css_set. | |
632 | * | |
633 | * The caller can also specify additional allowed conditions via @__c, such | |
634 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 635 | */ |
2219449a TH |
636 | #ifdef CONFIG_PROVE_RCU |
637 | extern struct mutex cgroup_mutex; | |
14611e51 TH |
638 | #define task_css_set_check(task, __c) \ |
639 | rcu_dereference_check((task)->cgroups, \ | |
640 | lockdep_is_held(&(task)->alloc_lock) || \ | |
641 | lockdep_is_held(&cgroup_mutex) || (__c)) | |
2219449a | 642 | #else |
14611e51 TH |
643 | #define task_css_set_check(task, __c) \ |
644 | rcu_dereference((task)->cgroups) | |
2219449a | 645 | #endif |
dc61b1d6 | 646 | |
14611e51 | 647 | /** |
8af01f56 | 648 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
649 | * @task: the target task |
650 | * @subsys_id: the target subsystem ID | |
651 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
652 | * | |
653 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
654 | * synchronization rules are the same as task_css_set_check(). | |
655 | */ | |
8af01f56 | 656 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
657 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
658 | ||
659 | /** | |
660 | * task_css_set - obtain a task's css_set | |
661 | * @task: the task to obtain css_set for | |
662 | * | |
663 | * See task_css_set_check(). | |
664 | */ | |
665 | static inline struct css_set *task_css_set(struct task_struct *task) | |
666 | { | |
667 | return task_css_set_check(task, false); | |
668 | } | |
669 | ||
670 | /** | |
8af01f56 | 671 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
672 | * @task: the target task |
673 | * @subsys_id: the target subsystem ID | |
674 | * | |
8af01f56 | 675 | * See task_css_check(). |
14611e51 | 676 | */ |
8af01f56 TH |
677 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
678 | int subsys_id) | |
ddbcc7e8 | 679 | { |
8af01f56 | 680 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
681 | } |
682 | ||
8af01f56 TH |
683 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
684 | int subsys_id) | |
ddbcc7e8 | 685 | { |
8af01f56 | 686 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
687 | } |
688 | ||
492eb21b TH |
689 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, |
690 | struct cgroup_subsys_state *parent); | |
53fa5261 | 691 | |
1cb650b9 LZ |
692 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); |
693 | ||
574bd9f7 | 694 | /** |
492eb21b TH |
695 | * css_for_each_child - iterate through children of a css |
696 | * @pos: the css * to use as the loop cursor | |
697 | * @parent: css whose children to walk | |
574bd9f7 | 698 | * |
492eb21b TH |
699 | * Walk @parent's children. Must be called under rcu_read_lock(). A child |
700 | * css which hasn't finished ->css_online() or already has finished | |
92fb9748 | 701 | * ->css_offline() may show up during traversal and it's each subsystem's |
574bd9f7 TH |
702 | * responsibility to verify that each @pos is alive. |
703 | * | |
92fb9748 | 704 | * If a subsystem synchronizes against the parent in its ->css_online() and |
492eb21b | 705 | * before starting iterating, a css which finished ->css_online() is |
92fb9748 | 706 | * guaranteed to be visible in the future iterations. |
75501a6d TH |
707 | * |
708 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
709 | * caller is responsible for ensuring that @pos remains accessible until | |
710 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 711 | */ |
492eb21b TH |
712 | #define css_for_each_child(pos, parent) \ |
713 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
714 | (pos) = css_next_child((pos), (parent))) | |
574bd9f7 | 715 | |
492eb21b TH |
716 | struct cgroup_subsys_state * |
717 | css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
718 | struct cgroup_subsys_state *css); | |
719 | ||
720 | struct cgroup_subsys_state * | |
721 | css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
574bd9f7 TH |
722 | |
723 | /** | |
492eb21b TH |
724 | * css_for_each_descendant_pre - pre-order walk of a css's descendants |
725 | * @pos: the css * to use as the loop cursor | |
726 | * @root: css whose descendants to walk | |
574bd9f7 | 727 | * |
bd8815a6 TH |
728 | * Walk @root's descendants. @root is included in the iteration and the |
729 | * first node to be visited. Must be called under rcu_read_lock(). A | |
492eb21b | 730 | * descendant css which hasn't finished ->css_online() or already has |
92fb9748 | 731 | * finished ->css_offline() may show up during traversal and it's each |
574bd9f7 TH |
732 | * subsystem's responsibility to verify that each @pos is alive. |
733 | * | |
92fb9748 TH |
734 | * If a subsystem synchronizes against the parent in its ->css_online() and |
735 | * before starting iterating, and synchronizes against @pos on each | |
492eb21b | 736 | * iteration, any descendant css which finished ->css_online() is |
574bd9f7 TH |
737 | * guaranteed to be visible in the future iterations. |
738 | * | |
739 | * In other words, the following guarantees that a descendant can't escape | |
740 | * state updates of its ancestors. | |
741 | * | |
492eb21b | 742 | * my_online(@css) |
574bd9f7 | 743 | * { |
492eb21b TH |
744 | * Lock @css's parent and @css; |
745 | * Inherit state from the parent; | |
574bd9f7 TH |
746 | * Unlock both. |
747 | * } | |
748 | * | |
492eb21b | 749 | * my_update_state(@css) |
574bd9f7 | 750 | * { |
492eb21b | 751 | * css_for_each_descendant_pre(@pos, @css) { |
574bd9f7 | 752 | * Lock @pos; |
bd8815a6 TH |
753 | * if (@pos == @css) |
754 | * Update @css's state; | |
755 | * else | |
756 | * Verify @pos is alive and inherit state from its parent; | |
574bd9f7 TH |
757 | * Unlock @pos; |
758 | * } | |
759 | * } | |
760 | * | |
761 | * As long as the inheriting step, including checking the parent state, is | |
762 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
763 | * while inheriting. The state update to the parent is guaranteed to be | |
764 | * visible by walking order and, as long as inheriting operations to the | |
765 | * same @pos are atomic to each other, multiple updates racing each other | |
766 | * still result in the correct state. It's guaranateed that at least one | |
492eb21b | 767 | * inheritance happens for any css after the latest update to its parent. |
574bd9f7 TH |
768 | * |
769 | * If checking parent's state requires locking the parent, each inheriting | |
770 | * iteration should lock and unlock both @pos->parent and @pos. | |
771 | * | |
772 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 773 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 | 774 | * operations. |
75501a6d TH |
775 | * |
776 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
777 | * caller is responsible for ensuring that @pos remains accessible until | |
778 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 779 | */ |
492eb21b TH |
780 | #define css_for_each_descendant_pre(pos, css) \ |
781 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
782 | (pos) = css_next_descendant_pre((pos), (css))) | |
574bd9f7 | 783 | |
492eb21b TH |
784 | struct cgroup_subsys_state * |
785 | css_next_descendant_post(struct cgroup_subsys_state *pos, | |
786 | struct cgroup_subsys_state *css); | |
574bd9f7 TH |
787 | |
788 | /** | |
492eb21b TH |
789 | * css_for_each_descendant_post - post-order walk of a css's descendants |
790 | * @pos: the css * to use as the loop cursor | |
791 | * @css: css whose descendants to walk | |
574bd9f7 | 792 | * |
492eb21b | 793 | * Similar to css_for_each_descendant_pre() but performs post-order |
bd8815a6 TH |
794 | * traversal instead. @root is included in the iteration and the last |
795 | * node to be visited. Note that the walk visibility guarantee described | |
796 | * in pre-order walk doesn't apply the same to post-order walks. | |
574bd9f7 | 797 | */ |
492eb21b TH |
798 | #define css_for_each_descendant_post(pos, css) \ |
799 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
800 | (pos) = css_next_descendant_post((pos), (css))) | |
574bd9f7 | 801 | |
72ec7029 TH |
802 | /* A css_task_iter should be treated as an opaque object */ |
803 | struct css_task_iter { | |
804 | struct cgroup_subsys_state *origin_css; | |
0942eeee TH |
805 | struct list_head *cset_link; |
806 | struct list_head *task; | |
817929ec PM |
807 | }; |
808 | ||
72ec7029 TH |
809 | void css_task_iter_start(struct cgroup_subsys_state *css, |
810 | struct css_task_iter *it); | |
811 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
812 | void css_task_iter_end(struct css_task_iter *it); | |
e535837b | 813 | |
72ec7029 TH |
814 | int css_scan_tasks(struct cgroup_subsys_state *css, |
815 | bool (*test)(struct task_struct *, void *), | |
816 | void (*process)(struct task_struct *, void *), | |
817 | void *data, struct ptr_heap *heap); | |
e535837b | 818 | |
31583bb0 | 819 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 820 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 821 | |
5a17f543 TH |
822 | struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry, |
823 | struct cgroup_subsys *ss); | |
38460b48 | 824 | |
ddbcc7e8 PM |
825 | #else /* !CONFIG_CGROUPS */ |
826 | ||
827 | static inline int cgroup_init_early(void) { return 0; } | |
828 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 829 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 830 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 831 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 | 832 | |
846c7bb0 BS |
833 | static inline int cgroupstats_build(struct cgroupstats *stats, |
834 | struct dentry *dentry) | |
835 | { | |
836 | return -EINVAL; | |
837 | } | |
ddbcc7e8 | 838 | |
d7926ee3 | 839 | /* No cgroups - nothing to do */ |
31583bb0 MT |
840 | static inline int cgroup_attach_task_all(struct task_struct *from, |
841 | struct task_struct *t) | |
842 | { | |
843 | return 0; | |
844 | } | |
d7926ee3 | 845 | |
ddbcc7e8 PM |
846 | #endif /* !CONFIG_CGROUPS */ |
847 | ||
848 | #endif /* _LINUX_CGROUP_H */ |