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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> |
cc31edce | 17 | #include <linux/rwsem.h> |
38460b48 | 18 | #include <linux/idr.h> |
48ddbe19 | 19 | #include <linux/workqueue.h> |
25a7e684 | 20 | #include <linux/fs.h> |
d3daf28d | 21 | #include <linux/percpu-refcount.h> |
7da11279 | 22 | #include <linux/seq_file.h> |
2bd59d48 | 23 | #include <linux/kernfs.h> |
ddbcc7e8 PM |
24 | |
25 | #ifdef CONFIG_CGROUPS | |
26 | ||
3dd06ffa | 27 | struct cgroup_root; |
ddbcc7e8 PM |
28 | struct cgroup_subsys; |
29 | struct inode; | |
84eea842 | 30 | struct cgroup; |
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); |
1ec41830 | 36 | extern void cgroup_exit(struct task_struct *p); |
846c7bb0 BS |
37 | extern int cgroupstats_build(struct cgroupstats *stats, |
38 | struct dentry *dentry); | |
ddbcc7e8 | 39 | |
8d8b97ba | 40 | extern int proc_cgroup_show(struct seq_file *, void *); |
a424316c | 41 | |
3ed80a62 | 42 | /* define the enumeration of all cgroup subsystems */ |
073219e9 | 43 | #define SUBSYS(_x) _x ## _cgrp_id, |
817929ec PM |
44 | enum cgroup_subsys_id { |
45 | #include <linux/cgroup_subsys.h> | |
a6f00298 | 46 | CGROUP_SUBSYS_COUNT, |
817929ec PM |
47 | }; |
48 | #undef SUBSYS | |
49 | ||
ddbcc7e8 PM |
50 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
51 | struct cgroup_subsys_state { | |
72c97e54 | 52 | /* the cgroup that this css is attached to */ |
ddbcc7e8 PM |
53 | struct cgroup *cgroup; |
54 | ||
72c97e54 TH |
55 | /* the cgroup subsystem that this css is attached to */ |
56 | struct cgroup_subsys *ss; | |
57 | ||
d3daf28d TH |
58 | /* reference count - access via css_[try]get() and css_put() */ |
59 | struct percpu_ref refcnt; | |
ddbcc7e8 | 60 | |
0ae78e0b TH |
61 | /* the parent css */ |
62 | struct cgroup_subsys_state *parent; | |
63 | ||
ddbcc7e8 | 64 | unsigned long flags; |
48ddbe19 | 65 | |
0c21ead1 TH |
66 | /* percpu_ref killing and RCU release */ |
67 | struct rcu_head rcu_head; | |
35ef10da | 68 | struct work_struct destroy_work; |
ddbcc7e8 PM |
69 | }; |
70 | ||
71 | /* bits in struct cgroup_subsys_state flags field */ | |
72 | enum { | |
38b53aba | 73 | CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */ |
92fb9748 | 74 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
ddbcc7e8 PM |
75 | }; |
76 | ||
5de0107e TH |
77 | /** |
78 | * css_get - obtain a reference on the specified css | |
79 | * @css: target css | |
80 | * | |
81 | * The caller must already have a reference. | |
ddbcc7e8 | 82 | */ |
ddbcc7e8 PM |
83 | static inline void css_get(struct cgroup_subsys_state *css) |
84 | { | |
85 | /* We don't need to reference count the root state */ | |
38b53aba | 86 | if (!(css->flags & CSS_ROOT)) |
d3daf28d | 87 | percpu_ref_get(&css->refcnt); |
ddbcc7e8 | 88 | } |
e7c5ec91 | 89 | |
5de0107e TH |
90 | /** |
91 | * css_tryget - try to obtain a reference on the specified css | |
92 | * @css: target css | |
93 | * | |
94 | * Obtain a reference on @css if it's alive. The caller naturally needs to | |
95 | * ensure that @css is accessible but doesn't have to be holding a | |
96 | * reference on it - IOW, RCU protected access is good enough for this | |
97 | * function. Returns %true if a reference count was successfully obtained; | |
98 | * %false otherwise. | |
99 | */ | |
e7c5ec91 PM |
100 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
101 | { | |
38b53aba | 102 | if (css->flags & CSS_ROOT) |
e7c5ec91 | 103 | return true; |
d3daf28d | 104 | return percpu_ref_tryget(&css->refcnt); |
e7c5ec91 PM |
105 | } |
106 | ||
5de0107e TH |
107 | /** |
108 | * css_put - put a css reference | |
109 | * @css: target css | |
110 | * | |
111 | * Put a reference obtained via css_get() and css_tryget(). | |
112 | */ | |
ddbcc7e8 PM |
113 | static inline void css_put(struct cgroup_subsys_state *css) |
114 | { | |
38b53aba | 115 | if (!(css->flags & CSS_ROOT)) |
d3daf28d | 116 | percpu_ref_put(&css->refcnt); |
ddbcc7e8 PM |
117 | } |
118 | ||
3116f0e3 PM |
119 | /* bits in struct cgroup flags field */ |
120 | enum { | |
121 | /* Control Group is dead */ | |
54766d4a | 122 | CGRP_DEAD, |
d20a390a PM |
123 | /* |
124 | * Control Group has previously had a child cgroup or a task, | |
125 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) | |
126 | */ | |
3116f0e3 PM |
127 | CGRP_RELEASABLE, |
128 | /* Control Group requires release notifications to userspace */ | |
129 | CGRP_NOTIFY_ON_RELEASE, | |
97978e6d | 130 | /* |
2260e7fc TH |
131 | * Clone the parent's configuration when creating a new child |
132 | * cpuset cgroup. For historical reasons, this option can be | |
133 | * specified at mount time and thus is implemented here. | |
97978e6d | 134 | */ |
2260e7fc | 135 | CGRP_CPUSET_CLONE_CHILDREN, |
873fe09e TH |
136 | /* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */ |
137 | CGRP_SANE_BEHAVIOR, | |
3116f0e3 PM |
138 | }; |
139 | ||
ddbcc7e8 PM |
140 | struct cgroup { |
141 | unsigned long flags; /* "unsigned long" so bitops work */ | |
142 | ||
b414dc09 LZ |
143 | /* |
144 | * idr allocated in-hierarchy ID. | |
145 | * | |
146 | * The ID of the root cgroup is always 0, and a new cgroup | |
147 | * will be assigned with a smallest available ID. | |
0ab02ca8 LZ |
148 | * |
149 | * Allocating/Removing ID must be protected by cgroup_mutex. | |
b414dc09 LZ |
150 | */ |
151 | int id; | |
0a950f65 | 152 | |
f20104de TH |
153 | /* the number of attached css's */ |
154 | int nr_css; | |
155 | ||
2bd59d48 TH |
156 | atomic_t refcnt; |
157 | ||
ddbcc7e8 PM |
158 | /* |
159 | * We link our 'sibling' struct into our parent's 'children'. | |
160 | * Our children link their 'sibling' into our 'children'. | |
161 | */ | |
162 | struct list_head sibling; /* my parent's children */ | |
163 | struct list_head children; /* my children */ | |
164 | ||
d20a390a | 165 | struct cgroup *parent; /* my parent */ |
2bd59d48 | 166 | struct kernfs_node *kn; /* cgroup kernfs entry */ |
ddbcc7e8 | 167 | |
53fa5261 TH |
168 | /* |
169 | * Monotonically increasing unique serial number which defines a | |
170 | * uniform order among all cgroups. It's guaranteed that all | |
171 | * ->children lists are in the ascending order of ->serial_nr. | |
172 | * It's used to allow interrupting and resuming iterations. | |
173 | */ | |
174 | u64 serial_nr; | |
175 | ||
94419627 TH |
176 | /* The bitmask of subsystems attached to this cgroup */ |
177 | unsigned long subsys_mask; | |
178 | ||
ddbcc7e8 | 179 | /* Private pointers for each registered subsystem */ |
73e80ed8 | 180 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; |
ddbcc7e8 | 181 | |
3dd06ffa | 182 | struct cgroup_root *root; |
817929ec PM |
183 | |
184 | /* | |
69d0206c TH |
185 | * List of cgrp_cset_links pointing at css_sets with tasks in this |
186 | * cgroup. Protected by css_set_lock. | |
817929ec | 187 | */ |
69d0206c | 188 | struct list_head cset_links; |
81a6a5cd PM |
189 | |
190 | /* | |
191 | * Linked list running through all cgroups that can | |
192 | * potentially be reaped by the release agent. Protected by | |
193 | * release_list_lock | |
194 | */ | |
195 | struct list_head release_list; | |
cc31edce | 196 | |
72a8cb30 BB |
197 | /* |
198 | * list of pidlists, up to two for each namespace (one for procs, one | |
199 | * for tasks); created on demand. | |
200 | */ | |
201 | struct list_head pidlists; | |
202 | struct mutex pidlist_mutex; | |
a47295e6 | 203 | |
67f4c36f TH |
204 | /* dummy css with NULL ->ss, points back to this cgroup */ |
205 | struct cgroup_subsys_state dummy_css; | |
206 | ||
d3daf28d | 207 | /* For css percpu_ref killing and RCU-protected deletion */ |
a47295e6 | 208 | struct rcu_head rcu_head; |
ea15f8cc | 209 | struct work_struct destroy_work; |
817929ec PM |
210 | }; |
211 | ||
25a7e684 TH |
212 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
213 | ||
3dd06ffa | 214 | /* cgroup_root->flags */ |
25a7e684 | 215 | enum { |
873fe09e TH |
216 | /* |
217 | * Unfortunately, cgroup core and various controllers are riddled | |
218 | * with idiosyncrasies and pointless options. The following flag, | |
219 | * when set, will force sane behavior - some options are forced on, | |
220 | * others are disallowed, and some controllers will change their | |
221 | * hierarchical or other behaviors. | |
222 | * | |
223 | * The set of behaviors affected by this flag are still being | |
224 | * determined and developed and the mount option for this flag is | |
225 | * prefixed with __DEVEL__. The prefix will be dropped once we | |
226 | * reach the point where all behaviors are compatible with the | |
227 | * planned unified hierarchy, which will automatically turn on this | |
228 | * flag. | |
229 | * | |
230 | * The followings are the behaviors currently affected this flag. | |
231 | * | |
d3ba07c3 TH |
232 | * - Mount options "noprefix", "xattr", "clone_children", |
233 | * "release_agent" and "name" are disallowed. | |
873fe09e TH |
234 | * |
235 | * - When mounting an existing superblock, mount options should | |
236 | * match. | |
237 | * | |
238 | * - Remount is disallowed. | |
239 | * | |
0b0585c3 LT |
240 | * - rename(2) is disallowed. |
241 | * | |
f63674fd TH |
242 | * - "tasks" is removed. Everything should be at process |
243 | * granularity. Use "cgroup.procs" instead. | |
f00baae7 | 244 | * |
afb2bc14 TH |
245 | * - "cgroup.procs" is not sorted. pids will be unique unless they |
246 | * got recycled inbetween reads. | |
247 | * | |
f63674fd TH |
248 | * - "release_agent" and "notify_on_release" are removed. |
249 | * Replacement notification mechanism will be implemented. | |
873fe09e | 250 | * |
d3ba07c3 | 251 | * - "cgroup.clone_children" is removed. |
86bf4b68 | 252 | * |
a2dd4247 TH |
253 | * - If mount is requested with sane_behavior but without any |
254 | * subsystem, the default unified hierarchy is mounted. | |
255 | * | |
5c5cc623 LZ |
256 | * - cpuset: tasks will be kept in empty cpusets when hotplug happens |
257 | * and take masks of ancestors with non-empty cpus/mems, instead of | |
258 | * being moved to an ancestor. | |
259 | * | |
88fa523b LZ |
260 | * - cpuset: a task can be moved into an empty cpuset, and again it |
261 | * takes masks of ancestors. | |
6db8e85c | 262 | * |
f63674fd TH |
263 | * - memcg: use_hierarchy is on by default and the cgroup file for |
264 | * the flag is not created. | |
f00baae7 | 265 | * |
9138125b | 266 | * - blkcg: blk-throttle becomes properly hierarchical. |
873fe09e TH |
267 | */ |
268 | CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), | |
269 | ||
25a7e684 TH |
270 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
271 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
0ce6cba3 TH |
272 | |
273 | /* mount options live below bit 16 */ | |
274 | CGRP_ROOT_OPTION_MASK = (1 << 16) - 1, | |
25a7e684 TH |
275 | }; |
276 | ||
277 | /* | |
3dd06ffa | 278 | * A cgroup_root represents the root of a cgroup hierarchy, and may be |
2bd59d48 | 279 | * associated with a kernfs_root to form an active hierarchy. This is |
25a7e684 TH |
280 | * internal to cgroup core. Don't access directly from controllers. |
281 | */ | |
3dd06ffa | 282 | struct cgroup_root { |
2bd59d48 | 283 | struct kernfs_root *kf_root; |
25a7e684 | 284 | |
25a7e684 TH |
285 | /* Unique id for this hierarchy. */ |
286 | int hierarchy_id; | |
287 | ||
776f02fa | 288 | /* The root cgroup. Root is destroyed on its release. */ |
3dd06ffa | 289 | struct cgroup cgrp; |
25a7e684 | 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 | 329 | /* |
c7561128 TH |
330 | * Lists running through all tasks using this cgroup group. |
331 | * mg_tasks lists tasks which belong to this cset but are in the | |
332 | * process of being migrated out or in. Protected by | |
333 | * css_set_rwsem, but, during migration, once tasks are moved to | |
334 | * mg_tasks, it can be read safely while holding cgroup_mutex. | |
817929ec PM |
335 | */ |
336 | struct list_head tasks; | |
c7561128 | 337 | struct list_head mg_tasks; |
817929ec PM |
338 | |
339 | /* | |
69d0206c TH |
340 | * List of cgrp_cset_links pointing at cgroups referenced from this |
341 | * css_set. Protected by css_set_lock. | |
817929ec | 342 | */ |
69d0206c | 343 | struct list_head cgrp_links; |
817929ec PM |
344 | |
345 | /* | |
3ed80a62 TH |
346 | * Set of subsystem states, one for each subsystem. This array is |
347 | * immutable after creation apart from the init_css_set during | |
348 | * subsystem registration (at boot time). | |
817929ec PM |
349 | */ |
350 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d | 351 | |
b3dc094e TH |
352 | /* |
353 | * List of csets participating in the on-going migration either as | |
354 | * source or destination. Protected by cgroup_mutex. | |
355 | */ | |
1958d2d5 | 356 | struct list_head mg_preload_node; |
b3dc094e TH |
357 | struct list_head mg_node; |
358 | ||
359 | /* | |
360 | * If this cset is acting as the source of migration the following | |
361 | * two fields are set. mg_src_cgrp is the source cgroup of the | |
362 | * on-going migration and mg_dst_cset is the destination cset the | |
363 | * target tasks on this cset should be migrated to. Protected by | |
364 | * cgroup_mutex. | |
365 | */ | |
366 | struct cgroup *mg_src_cgrp; | |
367 | struct css_set *mg_dst_cset; | |
368 | ||
c378369d BB |
369 | /* For RCU-protected deletion */ |
370 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
371 | }; |
372 | ||
d20a390a PM |
373 | /* |
374 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
375 | * |
376 | * When reading/writing to a file: | |
a043e3b2 | 377 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
378 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
379 | */ | |
380 | ||
8e3f6541 | 381 | /* cftype->flags */ |
02c402d9 | 382 | enum { |
6f4b7e63 LZ |
383 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ |
384 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
02c402d9 | 385 | CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */ |
9fa4db33 | 386 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
8cbbf2c9 | 387 | CFTYPE_ONLY_ON_DFL = (1 << 4), /* only on default hierarchy */ |
02c402d9 | 388 | }; |
8e3f6541 TH |
389 | |
390 | #define MAX_CFTYPE_NAME 64 | |
391 | ||
ddbcc7e8 | 392 | struct cftype { |
d20a390a PM |
393 | /* |
394 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
395 | * subsystem, followed by a period. Zero length string indicates |
396 | * end of cftype array. | |
d20a390a | 397 | */ |
ddbcc7e8 PM |
398 | char name[MAX_CFTYPE_NAME]; |
399 | int private; | |
099fca32 LZ |
400 | /* |
401 | * If not 0, file mode is set to this value, otherwise it will | |
402 | * be figured out automatically | |
403 | */ | |
a5e7ed32 | 404 | umode_t mode; |
db3b1497 PM |
405 | |
406 | /* | |
5f469907 TH |
407 | * The maximum length of string, excluding trailing nul, that can |
408 | * be passed to write_string. If < PAGE_SIZE-1, PAGE_SIZE-1 is | |
409 | * assumed. | |
db3b1497 PM |
410 | */ |
411 | size_t max_write_len; | |
412 | ||
8e3f6541 TH |
413 | /* CFTYPE_* flags */ |
414 | unsigned int flags; | |
415 | ||
2bb566cb | 416 | /* |
0adb0704 TH |
417 | * Fields used for internal bookkeeping. Initialized automatically |
418 | * during registration. | |
2bb566cb | 419 | */ |
0adb0704 TH |
420 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ |
421 | struct list_head node; /* anchored at ss->cfts */ | |
2bd59d48 TH |
422 | struct kernfs_ops *kf_ops; |
423 | ||
ddbcc7e8 | 424 | /* |
f4c753b7 | 425 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
426 | * single integer. Use it in place of read() |
427 | */ | |
182446d0 | 428 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); |
e73d2c61 PM |
429 | /* |
430 | * read_s64() is a signed version of read_u64() | |
431 | */ | |
182446d0 | 432 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); |
2da8ca82 TH |
433 | |
434 | /* generic seq_file read interface */ | |
435 | int (*seq_show)(struct seq_file *sf, void *v); | |
91796569 | 436 | |
6612f05b TH |
437 | /* optional ops, implement all or none */ |
438 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
439 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
440 | void (*seq_stop)(struct seq_file *sf, void *v); | |
441 | ||
355e0c48 | 442 | /* |
f4c753b7 | 443 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
444 | * a single integer (as parsed by simple_strtoull) from |
445 | * userspace. Use in place of write(); return 0 or error. | |
446 | */ | |
182446d0 TH |
447 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, |
448 | u64 val); | |
e73d2c61 PM |
449 | /* |
450 | * write_s64() is a signed version of write_u64() | |
451 | */ | |
182446d0 TH |
452 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, |
453 | s64 val); | |
355e0c48 | 454 | |
db3b1497 PM |
455 | /* |
456 | * write_string() is passed a nul-terminated kernelspace | |
457 | * buffer of maximum length determined by max_write_len. | |
458 | * Returns 0 or -ve error code. | |
459 | */ | |
182446d0 | 460 | int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft, |
4d3bb511 | 461 | char *buffer); |
d447ea2f PE |
462 | /* |
463 | * trigger() callback can be used to get some kick from the | |
464 | * userspace, when the actual string written is not important | |
465 | * at all. The private field can be used to determine the | |
466 | * kick type for multiplexing. | |
467 | */ | |
182446d0 | 468 | int (*trigger)(struct cgroup_subsys_state *css, unsigned int event); |
2bd59d48 TH |
469 | |
470 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
471 | struct lock_class_key lockdep_key; | |
472 | #endif | |
ddbcc7e8 PM |
473 | }; |
474 | ||
a2dd4247 TH |
475 | extern struct cgroup_root cgrp_dfl_root; |
476 | ||
477 | static inline bool cgroup_on_dfl(const struct cgroup *cgrp) | |
478 | { | |
479 | return cgrp->root == &cgrp_dfl_root; | |
480 | } | |
481 | ||
873fe09e TH |
482 | /* |
483 | * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This | |
484 | * function can be called as long as @cgrp is accessible. | |
485 | */ | |
486 | static inline bool cgroup_sane_behavior(const struct cgroup *cgrp) | |
487 | { | |
488 | return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR; | |
489 | } | |
490 | ||
07bc356e TH |
491 | /* no synchronization, the result can only be used as a hint */ |
492 | static inline bool cgroup_has_tasks(struct cgroup *cgrp) | |
493 | { | |
494 | return !list_empty(&cgrp->cset_links); | |
495 | } | |
496 | ||
b1664924 TH |
497 | /* returns ino associated with a cgroup, 0 indicates unmounted root */ |
498 | static inline ino_t cgroup_ino(struct cgroup *cgrp) | |
499 | { | |
2bd59d48 TH |
500 | if (cgrp->kn) |
501 | return cgrp->kn->ino; | |
b1664924 TH |
502 | else |
503 | return 0; | |
504 | } | |
505 | ||
7da11279 TH |
506 | static inline struct cftype *seq_cft(struct seq_file *seq) |
507 | { | |
2bd59d48 TH |
508 | struct kernfs_open_file *of = seq->private; |
509 | ||
510 | return of->kn->priv; | |
7da11279 TH |
511 | } |
512 | ||
59f5296b TH |
513 | struct cgroup_subsys_state *seq_css(struct seq_file *seq); |
514 | ||
e61734c5 TH |
515 | /* |
516 | * Name / path handling functions. All are thin wrappers around the kernfs | |
517 | * counterparts and can be called under any context. | |
518 | */ | |
519 | ||
520 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) | |
521 | { | |
fdce6bf8 | 522 | return kernfs_name(cgrp->kn, buf, buflen); |
e61734c5 TH |
523 | } |
524 | ||
525 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, | |
526 | size_t buflen) | |
527 | { | |
fdce6bf8 | 528 | return kernfs_path(cgrp->kn, buf, buflen); |
e61734c5 TH |
529 | } |
530 | ||
531 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) | |
532 | { | |
fdce6bf8 | 533 | pr_cont_kernfs_name(cgrp->kn); |
e61734c5 TH |
534 | } |
535 | ||
536 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) | |
537 | { | |
fdce6bf8 | 538 | pr_cont_kernfs_path(cgrp->kn); |
e61734c5 TH |
539 | } |
540 | ||
541 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); | |
542 | ||
03b1cde6 | 543 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
2bb566cb | 544 | int cgroup_rm_cftypes(struct cftype *cfts); |
8e3f6541 | 545 | |
78574cf9 | 546 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
ddbcc7e8 | 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); | |
2f7ee569 TH |
555 | |
556 | /** | |
557 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
558 | * @task: the loop cursor | |
2f7ee569 TH |
559 | * @tset: taskset to iterate |
560 | */ | |
924f0d9a | 561 | #define cgroup_taskset_for_each(task, tset) \ |
2f7ee569 | 562 | for ((task) = cgroup_taskset_first((tset)); (task); \ |
924f0d9a | 563 | (task) = cgroup_taskset_next((tset))) |
2f7ee569 | 564 | |
21acb9ca TLSC |
565 | /* |
566 | * Control Group subsystem type. | |
567 | * See Documentation/cgroups/cgroups.txt for details | |
568 | */ | |
ddbcc7e8 PM |
569 | |
570 | struct cgroup_subsys { | |
eb95419b TH |
571 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); |
572 | int (*css_online)(struct cgroup_subsys_state *css); | |
573 | void (*css_offline)(struct cgroup_subsys_state *css); | |
574 | void (*css_free)(struct cgroup_subsys_state *css); | |
575 | ||
576 | int (*can_attach)(struct cgroup_subsys_state *css, | |
577 | struct cgroup_taskset *tset); | |
578 | void (*cancel_attach)(struct cgroup_subsys_state *css, | |
579 | struct cgroup_taskset *tset); | |
580 | void (*attach)(struct cgroup_subsys_state *css, | |
581 | struct cgroup_taskset *tset); | |
761b3ef5 | 582 | void (*fork)(struct task_struct *task); |
eb95419b TH |
583 | void (*exit)(struct cgroup_subsys_state *css, |
584 | struct cgroup_subsys_state *old_css, | |
761b3ef5 | 585 | struct task_struct *task); |
eb95419b | 586 | void (*bind)(struct cgroup_subsys_state *root_css); |
e5991371 | 587 | |
8bab8dde | 588 | int disabled; |
ddbcc7e8 | 589 | int early_init; |
48ddbe19 | 590 | |
8c7f6edb TH |
591 | /* |
592 | * If %false, this subsystem is properly hierarchical - | |
593 | * configuration, resource accounting and restriction on a parent | |
594 | * cgroup cover those of its children. If %true, hierarchy support | |
595 | * is broken in some ways - some subsystems ignore hierarchy | |
596 | * completely while others are only implemented half-way. | |
597 | * | |
598 | * It's now disallowed to create nested cgroups if the subsystem is | |
599 | * broken and cgroup core will emit a warning message on such | |
600 | * cases. Eventually, all subsystems will be made properly | |
601 | * hierarchical and this will go away. | |
602 | */ | |
603 | bool broken_hierarchy; | |
604 | bool warned_broken_hierarchy; | |
605 | ||
073219e9 | 606 | /* the following two fields are initialized automtically during boot */ |
aec25020 | 607 | int id; |
ddbcc7e8 PM |
608 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
609 | const char *name; | |
610 | ||
b85d2040 | 611 | /* link to parent, protected by cgroup_lock() */ |
3dd06ffa | 612 | struct cgroup_root *root; |
e6a1105b | 613 | |
0adb0704 TH |
614 | /* |
615 | * List of cftypes. Each entry is the first entry of an array | |
616 | * terminated by zero length name. | |
617 | */ | |
618 | struct list_head cfts; | |
8e3f6541 | 619 | |
de00ffa5 | 620 | /* base cftypes, automatically registered with subsys itself */ |
8e3f6541 | 621 | struct cftype *base_cftypes; |
ddbcc7e8 PM |
622 | }; |
623 | ||
073219e9 | 624 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
ddbcc7e8 PM |
625 | #include <linux/cgroup_subsys.h> |
626 | #undef SUBSYS | |
627 | ||
63876986 TH |
628 | /** |
629 | * css_parent - find the parent css | |
630 | * @css: the target cgroup_subsys_state | |
631 | * | |
632 | * Return the parent css of @css. This function is guaranteed to return | |
633 | * non-NULL parent as long as @css isn't the root. | |
634 | */ | |
635 | static inline | |
636 | struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) | |
637 | { | |
0ae78e0b | 638 | return css->parent; |
63876986 TH |
639 | } |
640 | ||
14611e51 TH |
641 | /** |
642 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
643 | * @task: the task to obtain css_set for | |
644 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
645 | * | |
646 | * A task's css_set is RCU protected, initialized and exited while holding | |
647 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
648 | * and task_lock() while the task is alive. This macro verifies that the | |
649 | * caller is inside proper critical section and returns @task's css_set. | |
650 | * | |
651 | * The caller can also specify additional allowed conditions via @__c, such | |
652 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 653 | */ |
2219449a TH |
654 | #ifdef CONFIG_PROVE_RCU |
655 | extern struct mutex cgroup_mutex; | |
0e1d768f | 656 | extern struct rw_semaphore css_set_rwsem; |
14611e51 TH |
657 | #define task_css_set_check(task, __c) \ |
658 | rcu_dereference_check((task)->cgroups, \ | |
0e1d768f TH |
659 | lockdep_is_held(&cgroup_mutex) || \ |
660 | lockdep_is_held(&css_set_rwsem) || \ | |
661 | ((task)->flags & PF_EXITING) || (__c)) | |
2219449a | 662 | #else |
14611e51 TH |
663 | #define task_css_set_check(task, __c) \ |
664 | rcu_dereference((task)->cgroups) | |
2219449a | 665 | #endif |
dc61b1d6 | 666 | |
14611e51 | 667 | /** |
8af01f56 | 668 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
669 | * @task: the target task |
670 | * @subsys_id: the target subsystem ID | |
671 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
672 | * | |
673 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
674 | * synchronization rules are the same as task_css_set_check(). | |
675 | */ | |
8af01f56 | 676 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
677 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
678 | ||
679 | /** | |
680 | * task_css_set - obtain a task's css_set | |
681 | * @task: the task to obtain css_set for | |
682 | * | |
683 | * See task_css_set_check(). | |
684 | */ | |
685 | static inline struct css_set *task_css_set(struct task_struct *task) | |
686 | { | |
687 | return task_css_set_check(task, false); | |
688 | } | |
689 | ||
690 | /** | |
8af01f56 | 691 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
692 | * @task: the target task |
693 | * @subsys_id: the target subsystem ID | |
694 | * | |
8af01f56 | 695 | * See task_css_check(). |
14611e51 | 696 | */ |
8af01f56 TH |
697 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
698 | int subsys_id) | |
ddbcc7e8 | 699 | { |
8af01f56 | 700 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
701 | } |
702 | ||
8af01f56 TH |
703 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
704 | int subsys_id) | |
ddbcc7e8 | 705 | { |
8af01f56 | 706 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
707 | } |
708 | ||
492eb21b TH |
709 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, |
710 | struct cgroup_subsys_state *parent); | |
53fa5261 | 711 | |
1cb650b9 LZ |
712 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); |
713 | ||
574bd9f7 | 714 | /** |
492eb21b TH |
715 | * css_for_each_child - iterate through children of a css |
716 | * @pos: the css * to use as the loop cursor | |
717 | * @parent: css whose children to walk | |
574bd9f7 | 718 | * |
492eb21b TH |
719 | * Walk @parent's children. Must be called under rcu_read_lock(). A child |
720 | * css which hasn't finished ->css_online() or already has finished | |
92fb9748 | 721 | * ->css_offline() may show up during traversal and it's each subsystem's |
574bd9f7 TH |
722 | * responsibility to verify that each @pos is alive. |
723 | * | |
92fb9748 | 724 | * If a subsystem synchronizes against the parent in its ->css_online() and |
492eb21b | 725 | * before starting iterating, a css which finished ->css_online() is |
92fb9748 | 726 | * guaranteed to be visible in the future iterations. |
75501a6d TH |
727 | * |
728 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
729 | * caller is responsible for ensuring that @pos remains accessible until | |
730 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 731 | */ |
492eb21b TH |
732 | #define css_for_each_child(pos, parent) \ |
733 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
734 | (pos) = css_next_child((pos), (parent))) | |
574bd9f7 | 735 | |
492eb21b TH |
736 | struct cgroup_subsys_state * |
737 | css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
738 | struct cgroup_subsys_state *css); | |
739 | ||
740 | struct cgroup_subsys_state * | |
741 | css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
574bd9f7 TH |
742 | |
743 | /** | |
492eb21b TH |
744 | * css_for_each_descendant_pre - pre-order walk of a css's descendants |
745 | * @pos: the css * to use as the loop cursor | |
746 | * @root: css whose descendants to walk | |
574bd9f7 | 747 | * |
bd8815a6 TH |
748 | * Walk @root's descendants. @root is included in the iteration and the |
749 | * first node to be visited. Must be called under rcu_read_lock(). A | |
492eb21b | 750 | * descendant css which hasn't finished ->css_online() or already has |
92fb9748 | 751 | * finished ->css_offline() may show up during traversal and it's each |
574bd9f7 TH |
752 | * subsystem's responsibility to verify that each @pos is alive. |
753 | * | |
92fb9748 TH |
754 | * If a subsystem synchronizes against the parent in its ->css_online() and |
755 | * before starting iterating, and synchronizes against @pos on each | |
492eb21b | 756 | * iteration, any descendant css which finished ->css_online() is |
574bd9f7 TH |
757 | * guaranteed to be visible in the future iterations. |
758 | * | |
759 | * In other words, the following guarantees that a descendant can't escape | |
760 | * state updates of its ancestors. | |
761 | * | |
492eb21b | 762 | * my_online(@css) |
574bd9f7 | 763 | * { |
492eb21b TH |
764 | * Lock @css's parent and @css; |
765 | * Inherit state from the parent; | |
574bd9f7 TH |
766 | * Unlock both. |
767 | * } | |
768 | * | |
492eb21b | 769 | * my_update_state(@css) |
574bd9f7 | 770 | * { |
492eb21b | 771 | * css_for_each_descendant_pre(@pos, @css) { |
574bd9f7 | 772 | * Lock @pos; |
bd8815a6 TH |
773 | * if (@pos == @css) |
774 | * Update @css's state; | |
775 | * else | |
776 | * Verify @pos is alive and inherit state from its parent; | |
574bd9f7 TH |
777 | * Unlock @pos; |
778 | * } | |
779 | * } | |
780 | * | |
781 | * As long as the inheriting step, including checking the parent state, is | |
782 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
783 | * while inheriting. The state update to the parent is guaranteed to be | |
784 | * visible by walking order and, as long as inheriting operations to the | |
785 | * same @pos are atomic to each other, multiple updates racing each other | |
786 | * still result in the correct state. It's guaranateed that at least one | |
492eb21b | 787 | * inheritance happens for any css after the latest update to its parent. |
574bd9f7 TH |
788 | * |
789 | * If checking parent's state requires locking the parent, each inheriting | |
790 | * iteration should lock and unlock both @pos->parent and @pos. | |
791 | * | |
792 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 793 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 | 794 | * operations. |
75501a6d TH |
795 | * |
796 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
797 | * caller is responsible for ensuring that @pos remains accessible until | |
798 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 799 | */ |
492eb21b TH |
800 | #define css_for_each_descendant_pre(pos, css) \ |
801 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
802 | (pos) = css_next_descendant_pre((pos), (css))) | |
574bd9f7 | 803 | |
492eb21b TH |
804 | struct cgroup_subsys_state * |
805 | css_next_descendant_post(struct cgroup_subsys_state *pos, | |
806 | struct cgroup_subsys_state *css); | |
574bd9f7 TH |
807 | |
808 | /** | |
492eb21b TH |
809 | * css_for_each_descendant_post - post-order walk of a css's descendants |
810 | * @pos: the css * to use as the loop cursor | |
811 | * @css: css whose descendants to walk | |
574bd9f7 | 812 | * |
492eb21b | 813 | * Similar to css_for_each_descendant_pre() but performs post-order |
bd8815a6 TH |
814 | * traversal instead. @root is included in the iteration and the last |
815 | * node to be visited. Note that the walk visibility guarantee described | |
816 | * in pre-order walk doesn't apply the same to post-order walks. | |
574bd9f7 | 817 | */ |
492eb21b TH |
818 | #define css_for_each_descendant_post(pos, css) \ |
819 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
820 | (pos) = css_next_descendant_post((pos), (css))) | |
574bd9f7 | 821 | |
72ec7029 TH |
822 | /* A css_task_iter should be treated as an opaque object */ |
823 | struct css_task_iter { | |
824 | struct cgroup_subsys_state *origin_css; | |
0942eeee TH |
825 | struct list_head *cset_link; |
826 | struct list_head *task; | |
817929ec PM |
827 | }; |
828 | ||
72ec7029 TH |
829 | void css_task_iter_start(struct cgroup_subsys_state *css, |
830 | struct css_task_iter *it); | |
831 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
832 | void css_task_iter_end(struct css_task_iter *it); | |
e535837b | 833 | |
31583bb0 | 834 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 835 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 836 | |
5a17f543 TH |
837 | struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry, |
838 | struct cgroup_subsys *ss); | |
38460b48 | 839 | |
ddbcc7e8 PM |
840 | #else /* !CONFIG_CGROUPS */ |
841 | ||
842 | static inline int cgroup_init_early(void) { return 0; } | |
843 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 844 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 845 | static inline void cgroup_post_fork(struct task_struct *p) {} |
1ec41830 | 846 | static inline void cgroup_exit(struct task_struct *p) {} |
ddbcc7e8 | 847 | |
846c7bb0 BS |
848 | static inline int cgroupstats_build(struct cgroupstats *stats, |
849 | struct dentry *dentry) | |
850 | { | |
851 | return -EINVAL; | |
852 | } | |
ddbcc7e8 | 853 | |
d7926ee3 | 854 | /* No cgroups - nothing to do */ |
31583bb0 MT |
855 | static inline int cgroup_attach_task_all(struct task_struct *from, |
856 | struct task_struct *t) | |
857 | { | |
858 | return 0; | |
859 | } | |
d7926ee3 | 860 | |
ddbcc7e8 PM |
861 | #endif /* !CONFIG_CGROUPS */ |
862 | ||
863 | #endif /* _LINUX_CGROUP_H */ |