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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> |
d3daf28d | 23 | #include <linux/percpu-refcount.h> |
7da11279 | 24 | #include <linux/seq_file.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 | ||
65dff759 LZ |
141 | struct cgroup_name { |
142 | struct rcu_head rcu_head; | |
143 | char name[]; | |
3116f0e3 PM |
144 | }; |
145 | ||
ddbcc7e8 PM |
146 | struct cgroup { |
147 | unsigned long flags; /* "unsigned long" so bitops work */ | |
148 | ||
b414dc09 LZ |
149 | /* |
150 | * idr allocated in-hierarchy ID. | |
151 | * | |
152 | * The ID of the root cgroup is always 0, and a new cgroup | |
153 | * will be assigned with a smallest available ID. | |
154 | */ | |
155 | int id; | |
0a950f65 | 156 | |
f20104de TH |
157 | /* the number of attached css's */ |
158 | int nr_css; | |
159 | ||
ddbcc7e8 PM |
160 | /* |
161 | * We link our 'sibling' struct into our parent's 'children'. | |
162 | * Our children link their 'sibling' into our 'children'. | |
163 | */ | |
164 | struct list_head sibling; /* my parent's children */ | |
165 | struct list_head children; /* my children */ | |
05ef1d7c | 166 | struct list_head files; /* my files */ |
ddbcc7e8 | 167 | |
d20a390a | 168 | struct cgroup *parent; /* my parent */ |
febfcef6 | 169 | struct dentry *dentry; /* cgroup fs entry, RCU protected */ |
ddbcc7e8 | 170 | |
53fa5261 TH |
171 | /* |
172 | * Monotonically increasing unique serial number which defines a | |
173 | * uniform order among all cgroups. It's guaranteed that all | |
174 | * ->children lists are in the ascending order of ->serial_nr. | |
175 | * It's used to allow interrupting and resuming iterations. | |
176 | */ | |
177 | u64 serial_nr; | |
178 | ||
65dff759 LZ |
179 | /* |
180 | * This is a copy of dentry->d_name, and it's needed because | |
181 | * we can't use dentry->d_name in cgroup_path(). | |
182 | * | |
183 | * You must acquire rcu_read_lock() to access cgrp->name, and | |
184 | * the only place that can change it is rename(), which is | |
185 | * protected by parent dir's i_mutex. | |
186 | * | |
187 | * Normally you should use cgroup_name() wrapper rather than | |
188 | * access it directly. | |
189 | */ | |
190 | struct cgroup_name __rcu *name; | |
191 | ||
ddbcc7e8 | 192 | /* Private pointers for each registered subsystem */ |
73e80ed8 | 193 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; |
ddbcc7e8 PM |
194 | |
195 | struct cgroupfs_root *root; | |
817929ec PM |
196 | |
197 | /* | |
69d0206c TH |
198 | * List of cgrp_cset_links pointing at css_sets with tasks in this |
199 | * cgroup. Protected by css_set_lock. | |
817929ec | 200 | */ |
69d0206c | 201 | struct list_head cset_links; |
81a6a5cd PM |
202 | |
203 | /* | |
204 | * Linked list running through all cgroups that can | |
205 | * potentially be reaped by the release agent. Protected by | |
206 | * release_list_lock | |
207 | */ | |
208 | struct list_head release_list; | |
cc31edce | 209 | |
72a8cb30 BB |
210 | /* |
211 | * list of pidlists, up to two for each namespace (one for procs, one | |
212 | * for tasks); created on demand. | |
213 | */ | |
214 | struct list_head pidlists; | |
215 | struct mutex pidlist_mutex; | |
a47295e6 | 216 | |
67f4c36f TH |
217 | /* dummy css with NULL ->ss, points back to this cgroup */ |
218 | struct cgroup_subsys_state dummy_css; | |
219 | ||
d3daf28d | 220 | /* For css percpu_ref killing and RCU-protected deletion */ |
a47295e6 | 221 | struct rcu_head rcu_head; |
ea15f8cc | 222 | struct work_struct destroy_work; |
0dea1168 | 223 | |
03b1cde6 AR |
224 | /* directory xattrs */ |
225 | struct simple_xattrs xattrs; | |
817929ec PM |
226 | }; |
227 | ||
25a7e684 TH |
228 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
229 | ||
230 | /* cgroupfs_root->flags */ | |
231 | enum { | |
873fe09e TH |
232 | /* |
233 | * Unfortunately, cgroup core and various controllers are riddled | |
234 | * with idiosyncrasies and pointless options. The following flag, | |
235 | * when set, will force sane behavior - some options are forced on, | |
236 | * others are disallowed, and some controllers will change their | |
237 | * hierarchical or other behaviors. | |
238 | * | |
239 | * The set of behaviors affected by this flag are still being | |
240 | * determined and developed and the mount option for this flag is | |
241 | * prefixed with __DEVEL__. The prefix will be dropped once we | |
242 | * reach the point where all behaviors are compatible with the | |
243 | * planned unified hierarchy, which will automatically turn on this | |
244 | * flag. | |
245 | * | |
246 | * The followings are the behaviors currently affected this flag. | |
247 | * | |
248 | * - Mount options "noprefix" and "clone_children" are disallowed. | |
249 | * Also, cgroupfs file cgroup.clone_children is not created. | |
250 | * | |
251 | * - When mounting an existing superblock, mount options should | |
252 | * match. | |
253 | * | |
254 | * - Remount is disallowed. | |
255 | * | |
0b0585c3 LT |
256 | * - rename(2) is disallowed. |
257 | * | |
f63674fd TH |
258 | * - "tasks" is removed. Everything should be at process |
259 | * granularity. Use "cgroup.procs" instead. | |
f00baae7 | 260 | * |
afb2bc14 TH |
261 | * - "cgroup.procs" is not sorted. pids will be unique unless they |
262 | * got recycled inbetween reads. | |
263 | * | |
f63674fd TH |
264 | * - "release_agent" and "notify_on_release" are removed. |
265 | * Replacement notification mechanism will be implemented. | |
873fe09e | 266 | * |
5c5cc623 LZ |
267 | * - cpuset: tasks will be kept in empty cpusets when hotplug happens |
268 | * and take masks of ancestors with non-empty cpus/mems, instead of | |
269 | * being moved to an ancestor. | |
270 | * | |
88fa523b LZ |
271 | * - cpuset: a task can be moved into an empty cpuset, and again it |
272 | * takes masks of ancestors. | |
6db8e85c | 273 | * |
f63674fd TH |
274 | * - memcg: use_hierarchy is on by default and the cgroup file for |
275 | * the flag is not created. | |
f00baae7 | 276 | * |
9138125b | 277 | * - blkcg: blk-throttle becomes properly hierarchical. |
873fe09e TH |
278 | */ |
279 | CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), | |
280 | ||
25a7e684 TH |
281 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
282 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
0ce6cba3 TH |
283 | |
284 | /* mount options live below bit 16 */ | |
285 | CGRP_ROOT_OPTION_MASK = (1 << 16) - 1, | |
286 | ||
287 | CGRP_ROOT_SUBSYS_BOUND = (1 << 16), /* subsystems finished binding */ | |
25a7e684 TH |
288 | }; |
289 | ||
290 | /* | |
291 | * A cgroupfs_root represents the root of a cgroup hierarchy, and may be | |
292 | * associated with a superblock to form an active hierarchy. This is | |
293 | * internal to cgroup core. Don't access directly from controllers. | |
294 | */ | |
295 | struct cgroupfs_root { | |
296 | struct super_block *sb; | |
297 | ||
a8a648c4 | 298 | /* The bitmask of subsystems attached to this hierarchy */ |
25a7e684 TH |
299 | unsigned long subsys_mask; |
300 | ||
301 | /* Unique id for this hierarchy. */ | |
302 | int hierarchy_id; | |
303 | ||
25a7e684 TH |
304 | /* The root cgroup for this hierarchy */ |
305 | struct cgroup top_cgroup; | |
306 | ||
307 | /* Tracks how many cgroups are currently defined in hierarchy.*/ | |
308 | int number_of_cgroups; | |
309 | ||
310 | /* A list running through the active hierarchies */ | |
311 | struct list_head root_list; | |
312 | ||
25a7e684 TH |
313 | /* Hierarchy-specific flags */ |
314 | unsigned long flags; | |
315 | ||
316 | /* IDs for cgroups in this hierarchy */ | |
4e96ee8e | 317 | struct idr cgroup_idr; |
25a7e684 TH |
318 | |
319 | /* The path to use for release notifications. */ | |
320 | char release_agent_path[PATH_MAX]; | |
321 | ||
322 | /* The name for this hierarchy - may be empty */ | |
323 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
324 | }; | |
325 | ||
d20a390a PM |
326 | /* |
327 | * A css_set is a structure holding pointers to a set of | |
817929ec PM |
328 | * cgroup_subsys_state objects. This saves space in the task struct |
329 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
d20a390a PM |
330 | * list_add()/del() can bump the reference count on the entire cgroup |
331 | * set for a task. | |
817929ec PM |
332 | */ |
333 | ||
334 | struct css_set { | |
335 | ||
336 | /* Reference count */ | |
146aa1bd | 337 | atomic_t refcount; |
817929ec | 338 | |
472b1053 LZ |
339 | /* |
340 | * List running through all cgroup groups in the same hash | |
341 | * slot. Protected by css_set_lock | |
342 | */ | |
343 | struct hlist_node hlist; | |
344 | ||
817929ec PM |
345 | /* |
346 | * List running through all tasks using this cgroup | |
347 | * group. Protected by css_set_lock | |
348 | */ | |
349 | struct list_head tasks; | |
350 | ||
351 | /* | |
69d0206c TH |
352 | * List of cgrp_cset_links pointing at cgroups referenced from this |
353 | * css_set. Protected by css_set_lock. | |
817929ec | 354 | */ |
69d0206c | 355 | struct list_head cgrp_links; |
817929ec PM |
356 | |
357 | /* | |
3ed80a62 TH |
358 | * Set of subsystem states, one for each subsystem. This array is |
359 | * immutable after creation apart from the init_css_set during | |
360 | * subsystem registration (at boot time). | |
817929ec PM |
361 | */ |
362 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
c378369d BB |
363 | |
364 | /* For RCU-protected deletion */ | |
365 | struct rcu_head rcu_head; | |
ddbcc7e8 PM |
366 | }; |
367 | ||
d20a390a PM |
368 | /* |
369 | * struct cftype: handler definitions for cgroup control files | |
ddbcc7e8 PM |
370 | * |
371 | * When reading/writing to a file: | |
a043e3b2 | 372 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
373 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
374 | */ | |
375 | ||
8e3f6541 | 376 | /* cftype->flags */ |
02c402d9 | 377 | enum { |
6f4b7e63 LZ |
378 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ |
379 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
02c402d9 | 380 | CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */ |
9fa4db33 | 381 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
02c402d9 | 382 | }; |
8e3f6541 TH |
383 | |
384 | #define MAX_CFTYPE_NAME 64 | |
385 | ||
ddbcc7e8 | 386 | struct cftype { |
d20a390a PM |
387 | /* |
388 | * By convention, the name should begin with the name of the | |
8e3f6541 TH |
389 | * subsystem, followed by a period. Zero length string indicates |
390 | * end of cftype array. | |
d20a390a | 391 | */ |
ddbcc7e8 PM |
392 | char name[MAX_CFTYPE_NAME]; |
393 | int private; | |
099fca32 LZ |
394 | /* |
395 | * If not 0, file mode is set to this value, otherwise it will | |
396 | * be figured out automatically | |
397 | */ | |
a5e7ed32 | 398 | umode_t mode; |
db3b1497 PM |
399 | |
400 | /* | |
401 | * If non-zero, defines the maximum length of string that can | |
402 | * be passed to write_string; defaults to 64 | |
403 | */ | |
404 | size_t max_write_len; | |
405 | ||
8e3f6541 TH |
406 | /* CFTYPE_* flags */ |
407 | unsigned int flags; | |
408 | ||
2bb566cb TH |
409 | /* |
410 | * The subsys this file belongs to. Initialized automatically | |
411 | * during registration. NULL for cgroup core files. | |
412 | */ | |
413 | struct cgroup_subsys *ss; | |
414 | ||
ddbcc7e8 | 415 | /* |
f4c753b7 | 416 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
417 | * single integer. Use it in place of read() |
418 | */ | |
182446d0 | 419 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); |
e73d2c61 PM |
420 | /* |
421 | * read_s64() is a signed version of read_u64() | |
422 | */ | |
182446d0 | 423 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); |
2da8ca82 TH |
424 | |
425 | /* generic seq_file read interface */ | |
426 | int (*seq_show)(struct seq_file *sf, void *v); | |
91796569 | 427 | |
6612f05b TH |
428 | /* optional ops, implement all or none */ |
429 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
430 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
431 | void (*seq_stop)(struct seq_file *sf, void *v); | |
432 | ||
355e0c48 | 433 | /* |
f4c753b7 | 434 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
435 | * a single integer (as parsed by simple_strtoull) from |
436 | * userspace. Use in place of write(); return 0 or error. | |
437 | */ | |
182446d0 TH |
438 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, |
439 | u64 val); | |
e73d2c61 PM |
440 | /* |
441 | * write_s64() is a signed version of write_u64() | |
442 | */ | |
182446d0 TH |
443 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, |
444 | s64 val); | |
355e0c48 | 445 | |
db3b1497 PM |
446 | /* |
447 | * write_string() is passed a nul-terminated kernelspace | |
448 | * buffer of maximum length determined by max_write_len. | |
449 | * Returns 0 or -ve error code. | |
450 | */ | |
182446d0 | 451 | int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft, |
db3b1497 | 452 | const char *buffer); |
d447ea2f PE |
453 | /* |
454 | * trigger() callback can be used to get some kick from the | |
455 | * userspace, when the actual string written is not important | |
456 | * at all. The private field can be used to determine the | |
457 | * kick type for multiplexing. | |
458 | */ | |
182446d0 | 459 | int (*trigger)(struct cgroup_subsys_state *css, unsigned int event); |
ddbcc7e8 PM |
460 | }; |
461 | ||
8e3f6541 TH |
462 | /* |
463 | * cftype_sets describe cftypes belonging to a subsystem and are chained at | |
464 | * cgroup_subsys->cftsets. Each cftset points to an array of cftypes | |
465 | * terminated by zero length name. | |
466 | */ | |
467 | struct cftype_set { | |
468 | struct list_head node; /* chained at subsys->cftsets */ | |
03b1cde6 | 469 | struct cftype *cfts; |
8e3f6541 TH |
470 | }; |
471 | ||
7da11279 TH |
472 | /* |
473 | * cgroupfs file entry, pointed to from leaf dentry->d_fsdata. Don't | |
474 | * access directly. | |
475 | */ | |
476 | struct cfent { | |
477 | struct list_head node; | |
478 | struct dentry *dentry; | |
479 | struct cftype *type; | |
480 | struct cgroup_subsys_state *css; | |
481 | ||
482 | /* file xattrs */ | |
483 | struct simple_xattrs xattrs; | |
484 | }; | |
485 | ||
486 | /* seq_file->private points to the following, only ->priv is public */ | |
487 | struct cgroup_open_file { | |
488 | struct cfent *cfe; | |
489 | void *priv; | |
490 | }; | |
491 | ||
873fe09e TH |
492 | /* |
493 | * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This | |
494 | * function can be called as long as @cgrp is accessible. | |
495 | */ | |
496 | static inline bool cgroup_sane_behavior(const struct cgroup *cgrp) | |
497 | { | |
498 | return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR; | |
499 | } | |
500 | ||
65dff759 LZ |
501 | /* Caller should hold rcu_read_lock() */ |
502 | static inline const char *cgroup_name(const struct cgroup *cgrp) | |
503 | { | |
504 | return rcu_dereference(cgrp->name)->name; | |
505 | } | |
506 | ||
7da11279 TH |
507 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
508 | { | |
509 | struct cgroup_open_file *of = seq->private; | |
510 | return of->cfe->css; | |
511 | } | |
512 | ||
513 | static inline struct cftype *seq_cft(struct seq_file *seq) | |
514 | { | |
515 | struct cgroup_open_file *of = seq->private; | |
516 | return of->cfe->type; | |
517 | } | |
518 | ||
03b1cde6 | 519 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
2bb566cb | 520 | int cgroup_rm_cftypes(struct cftype *cfts); |
8e3f6541 | 521 | |
78574cf9 | 522 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
ddbcc7e8 | 523 | |
ffd2d883 | 524 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
913ffdb5 | 525 | int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); |
ddbcc7e8 | 526 | |
ffd2d883 | 527 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 528 | |
2f7ee569 TH |
529 | /* |
530 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys | |
531 | * methods. | |
532 | */ | |
533 | struct cgroup_taskset; | |
534 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
535 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
d99c8727 TH |
536 | struct cgroup_subsys_state *cgroup_taskset_cur_css(struct cgroup_taskset *tset, |
537 | int subsys_id); | |
2f7ee569 TH |
538 | int cgroup_taskset_size(struct cgroup_taskset *tset); |
539 | ||
540 | /** | |
541 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
542 | * @task: the loop cursor | |
d99c8727 | 543 | * @skip_css: skip if task's css matches this, %NULL to iterate through all |
2f7ee569 TH |
544 | * @tset: taskset to iterate |
545 | */ | |
d99c8727 | 546 | #define cgroup_taskset_for_each(task, skip_css, tset) \ |
2f7ee569 TH |
547 | for ((task) = cgroup_taskset_first((tset)); (task); \ |
548 | (task) = cgroup_taskset_next((tset))) \ | |
d99c8727 TH |
549 | if (!(skip_css) || \ |
550 | cgroup_taskset_cur_css((tset), \ | |
551 | (skip_css)->ss->subsys_id) != (skip_css)) | |
2f7ee569 | 552 | |
21acb9ca TLSC |
553 | /* |
554 | * Control Group subsystem type. | |
555 | * See Documentation/cgroups/cgroups.txt for details | |
556 | */ | |
ddbcc7e8 PM |
557 | |
558 | struct cgroup_subsys { | |
eb95419b TH |
559 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); |
560 | int (*css_online)(struct cgroup_subsys_state *css); | |
561 | void (*css_offline)(struct cgroup_subsys_state *css); | |
562 | void (*css_free)(struct cgroup_subsys_state *css); | |
563 | ||
564 | int (*can_attach)(struct cgroup_subsys_state *css, | |
565 | struct cgroup_taskset *tset); | |
566 | void (*cancel_attach)(struct cgroup_subsys_state *css, | |
567 | struct cgroup_taskset *tset); | |
568 | void (*attach)(struct cgroup_subsys_state *css, | |
569 | struct cgroup_taskset *tset); | |
761b3ef5 | 570 | void (*fork)(struct task_struct *task); |
eb95419b TH |
571 | void (*exit)(struct cgroup_subsys_state *css, |
572 | struct cgroup_subsys_state *old_css, | |
761b3ef5 | 573 | struct task_struct *task); |
eb95419b | 574 | void (*bind)(struct cgroup_subsys_state *root_css); |
e5991371 | 575 | |
8bab8dde | 576 | int disabled; |
ddbcc7e8 | 577 | int early_init; |
48ddbe19 | 578 | |
8c7f6edb TH |
579 | /* |
580 | * If %false, this subsystem is properly hierarchical - | |
581 | * configuration, resource accounting and restriction on a parent | |
582 | * cgroup cover those of its children. If %true, hierarchy support | |
583 | * is broken in some ways - some subsystems ignore hierarchy | |
584 | * completely while others are only implemented half-way. | |
585 | * | |
586 | * It's now disallowed to create nested cgroups if the subsystem is | |
587 | * broken and cgroup core will emit a warning message on such | |
588 | * cases. Eventually, all subsystems will be made properly | |
589 | * hierarchical and this will go away. | |
590 | */ | |
591 | bool broken_hierarchy; | |
592 | bool warned_broken_hierarchy; | |
593 | ||
073219e9 TH |
594 | /* the following two fields are initialized automtically during boot */ |
595 | int subsys_id; | |
ddbcc7e8 PM |
596 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
597 | const char *name; | |
598 | ||
b85d2040 | 599 | /* link to parent, protected by cgroup_lock() */ |
999cd8a4 | 600 | struct cgroupfs_root *root; |
e6a1105b | 601 | |
8e3f6541 TH |
602 | /* list of cftype_sets */ |
603 | struct list_head cftsets; | |
604 | ||
605 | /* base cftypes, automatically [de]registered with subsys itself */ | |
606 | struct cftype *base_cftypes; | |
607 | struct cftype_set base_cftset; | |
ddbcc7e8 PM |
608 | }; |
609 | ||
073219e9 | 610 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
ddbcc7e8 PM |
611 | #include <linux/cgroup_subsys.h> |
612 | #undef SUBSYS | |
613 | ||
63876986 TH |
614 | /** |
615 | * css_parent - find the parent css | |
616 | * @css: the target cgroup_subsys_state | |
617 | * | |
618 | * Return the parent css of @css. This function is guaranteed to return | |
619 | * non-NULL parent as long as @css isn't the root. | |
620 | */ | |
621 | static inline | |
622 | struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) | |
623 | { | |
0ae78e0b | 624 | return css->parent; |
63876986 TH |
625 | } |
626 | ||
14611e51 TH |
627 | /** |
628 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
629 | * @task: the task to obtain css_set for | |
630 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
631 | * | |
632 | * A task's css_set is RCU protected, initialized and exited while holding | |
633 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
634 | * and task_lock() while the task is alive. This macro verifies that the | |
635 | * caller is inside proper critical section and returns @task's css_set. | |
636 | * | |
637 | * The caller can also specify additional allowed conditions via @__c, such | |
638 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 639 | */ |
2219449a TH |
640 | #ifdef CONFIG_PROVE_RCU |
641 | extern struct mutex cgroup_mutex; | |
14611e51 TH |
642 | #define task_css_set_check(task, __c) \ |
643 | rcu_dereference_check((task)->cgroups, \ | |
644 | lockdep_is_held(&(task)->alloc_lock) || \ | |
645 | lockdep_is_held(&cgroup_mutex) || (__c)) | |
2219449a | 646 | #else |
14611e51 TH |
647 | #define task_css_set_check(task, __c) \ |
648 | rcu_dereference((task)->cgroups) | |
2219449a | 649 | #endif |
dc61b1d6 | 650 | |
14611e51 | 651 | /** |
8af01f56 | 652 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
653 | * @task: the target task |
654 | * @subsys_id: the target subsystem ID | |
655 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
656 | * | |
657 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
658 | * synchronization rules are the same as task_css_set_check(). | |
659 | */ | |
8af01f56 | 660 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
661 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
662 | ||
663 | /** | |
664 | * task_css_set - obtain a task's css_set | |
665 | * @task: the task to obtain css_set for | |
666 | * | |
667 | * See task_css_set_check(). | |
668 | */ | |
669 | static inline struct css_set *task_css_set(struct task_struct *task) | |
670 | { | |
671 | return task_css_set_check(task, false); | |
672 | } | |
673 | ||
674 | /** | |
8af01f56 | 675 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
676 | * @task: the target task |
677 | * @subsys_id: the target subsystem ID | |
678 | * | |
8af01f56 | 679 | * See task_css_check(). |
14611e51 | 680 | */ |
8af01f56 TH |
681 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
682 | int subsys_id) | |
ddbcc7e8 | 683 | { |
8af01f56 | 684 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
685 | } |
686 | ||
8af01f56 TH |
687 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
688 | int subsys_id) | |
ddbcc7e8 | 689 | { |
8af01f56 | 690 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
691 | } |
692 | ||
492eb21b TH |
693 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, |
694 | struct cgroup_subsys_state *parent); | |
53fa5261 | 695 | |
1cb650b9 LZ |
696 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); |
697 | ||
574bd9f7 | 698 | /** |
492eb21b TH |
699 | * css_for_each_child - iterate through children of a css |
700 | * @pos: the css * to use as the loop cursor | |
701 | * @parent: css whose children to walk | |
574bd9f7 | 702 | * |
492eb21b TH |
703 | * Walk @parent's children. Must be called under rcu_read_lock(). A child |
704 | * css which hasn't finished ->css_online() or already has finished | |
92fb9748 | 705 | * ->css_offline() may show up during traversal and it's each subsystem's |
574bd9f7 TH |
706 | * responsibility to verify that each @pos is alive. |
707 | * | |
92fb9748 | 708 | * If a subsystem synchronizes against the parent in its ->css_online() and |
492eb21b | 709 | * before starting iterating, a css which finished ->css_online() is |
92fb9748 | 710 | * guaranteed to be visible in the future iterations. |
75501a6d TH |
711 | * |
712 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
713 | * caller is responsible for ensuring that @pos remains accessible until | |
714 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 715 | */ |
492eb21b TH |
716 | #define css_for_each_child(pos, parent) \ |
717 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
718 | (pos) = css_next_child((pos), (parent))) | |
574bd9f7 | 719 | |
492eb21b TH |
720 | struct cgroup_subsys_state * |
721 | css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
722 | struct cgroup_subsys_state *css); | |
723 | ||
724 | struct cgroup_subsys_state * | |
725 | css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
574bd9f7 TH |
726 | |
727 | /** | |
492eb21b TH |
728 | * css_for_each_descendant_pre - pre-order walk of a css's descendants |
729 | * @pos: the css * to use as the loop cursor | |
730 | * @root: css whose descendants to walk | |
574bd9f7 | 731 | * |
bd8815a6 TH |
732 | * Walk @root's descendants. @root is included in the iteration and the |
733 | * first node to be visited. Must be called under rcu_read_lock(). A | |
492eb21b | 734 | * descendant css which hasn't finished ->css_online() or already has |
92fb9748 | 735 | * finished ->css_offline() may show up during traversal and it's each |
574bd9f7 TH |
736 | * subsystem's responsibility to verify that each @pos is alive. |
737 | * | |
92fb9748 TH |
738 | * If a subsystem synchronizes against the parent in its ->css_online() and |
739 | * before starting iterating, and synchronizes against @pos on each | |
492eb21b | 740 | * iteration, any descendant css which finished ->css_online() is |
574bd9f7 TH |
741 | * guaranteed to be visible in the future iterations. |
742 | * | |
743 | * In other words, the following guarantees that a descendant can't escape | |
744 | * state updates of its ancestors. | |
745 | * | |
492eb21b | 746 | * my_online(@css) |
574bd9f7 | 747 | * { |
492eb21b TH |
748 | * Lock @css's parent and @css; |
749 | * Inherit state from the parent; | |
574bd9f7 TH |
750 | * Unlock both. |
751 | * } | |
752 | * | |
492eb21b | 753 | * my_update_state(@css) |
574bd9f7 | 754 | * { |
492eb21b | 755 | * css_for_each_descendant_pre(@pos, @css) { |
574bd9f7 | 756 | * Lock @pos; |
bd8815a6 TH |
757 | * if (@pos == @css) |
758 | * Update @css's state; | |
759 | * else | |
760 | * Verify @pos is alive and inherit state from its parent; | |
574bd9f7 TH |
761 | * Unlock @pos; |
762 | * } | |
763 | * } | |
764 | * | |
765 | * As long as the inheriting step, including checking the parent state, is | |
766 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
767 | * while inheriting. The state update to the parent is guaranteed to be | |
768 | * visible by walking order and, as long as inheriting operations to the | |
769 | * same @pos are atomic to each other, multiple updates racing each other | |
770 | * still result in the correct state. It's guaranateed that at least one | |
492eb21b | 771 | * inheritance happens for any css after the latest update to its parent. |
574bd9f7 TH |
772 | * |
773 | * If checking parent's state requires locking the parent, each inheriting | |
774 | * iteration should lock and unlock both @pos->parent and @pos. | |
775 | * | |
776 | * Alternatively, a subsystem may choose to use a single global lock to | |
92fb9748 | 777 | * synchronize ->css_online() and ->css_offline() against tree-walking |
574bd9f7 | 778 | * operations. |
75501a6d TH |
779 | * |
780 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
781 | * caller is responsible for ensuring that @pos remains accessible until | |
782 | * the start of the next iteration by, for example, bumping the css refcnt. | |
574bd9f7 | 783 | */ |
492eb21b TH |
784 | #define css_for_each_descendant_pre(pos, css) \ |
785 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
786 | (pos) = css_next_descendant_pre((pos), (css))) | |
574bd9f7 | 787 | |
492eb21b TH |
788 | struct cgroup_subsys_state * |
789 | css_next_descendant_post(struct cgroup_subsys_state *pos, | |
790 | struct cgroup_subsys_state *css); | |
574bd9f7 TH |
791 | |
792 | /** | |
492eb21b TH |
793 | * css_for_each_descendant_post - post-order walk of a css's descendants |
794 | * @pos: the css * to use as the loop cursor | |
795 | * @css: css whose descendants to walk | |
574bd9f7 | 796 | * |
492eb21b | 797 | * Similar to css_for_each_descendant_pre() but performs post-order |
bd8815a6 TH |
798 | * traversal instead. @root is included in the iteration and the last |
799 | * node to be visited. Note that the walk visibility guarantee described | |
800 | * in pre-order walk doesn't apply the same to post-order walks. | |
574bd9f7 | 801 | */ |
492eb21b TH |
802 | #define css_for_each_descendant_post(pos, css) \ |
803 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
804 | (pos) = css_next_descendant_post((pos), (css))) | |
574bd9f7 | 805 | |
72ec7029 TH |
806 | /* A css_task_iter should be treated as an opaque object */ |
807 | struct css_task_iter { | |
808 | struct cgroup_subsys_state *origin_css; | |
0942eeee TH |
809 | struct list_head *cset_link; |
810 | struct list_head *task; | |
817929ec PM |
811 | }; |
812 | ||
72ec7029 TH |
813 | void css_task_iter_start(struct cgroup_subsys_state *css, |
814 | struct css_task_iter *it); | |
815 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
816 | void css_task_iter_end(struct css_task_iter *it); | |
e535837b | 817 | |
72ec7029 TH |
818 | int css_scan_tasks(struct cgroup_subsys_state *css, |
819 | bool (*test)(struct task_struct *, void *), | |
820 | void (*process)(struct task_struct *, void *), | |
821 | void *data, struct ptr_heap *heap); | |
e535837b | 822 | |
31583bb0 | 823 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
8cc99345 | 824 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
31583bb0 | 825 | |
35cf0836 TH |
826 | struct cgroup_subsys_state *css_from_dir(struct dentry *dentry, |
827 | struct cgroup_subsys *ss); | |
38460b48 | 828 | |
ddbcc7e8 PM |
829 | #else /* !CONFIG_CGROUPS */ |
830 | ||
831 | static inline int cgroup_init_early(void) { return 0; } | |
832 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 | 833 | static inline void cgroup_fork(struct task_struct *p) {} |
817929ec | 834 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 835 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 | 836 | |
846c7bb0 BS |
837 | static inline int cgroupstats_build(struct cgroupstats *stats, |
838 | struct dentry *dentry) | |
839 | { | |
840 | return -EINVAL; | |
841 | } | |
ddbcc7e8 | 842 | |
d7926ee3 | 843 | /* No cgroups - nothing to do */ |
31583bb0 MT |
844 | static inline int cgroup_attach_task_all(struct task_struct *from, |
845 | struct task_struct *t) | |
846 | { | |
847 | return 0; | |
848 | } | |
d7926ee3 | 849 | |
ddbcc7e8 PM |
850 | #endif /* !CONFIG_CGROUPS */ |
851 | ||
852 | #endif /* _LINUX_CGROUP_H */ |