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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> | |
846c7bb0 | 15 | #include <linux/cgroupstats.h> |
31a7df01 | 16 | #include <linux/prio_heap.h> |
cc31edce | 17 | #include <linux/rwsem.h> |
ddbcc7e8 PM |
18 | |
19 | #ifdef CONFIG_CGROUPS | |
20 | ||
21 | struct cgroupfs_root; | |
22 | struct cgroup_subsys; | |
23 | struct inode; | |
84eea842 | 24 | struct cgroup; |
ddbcc7e8 PM |
25 | |
26 | extern int cgroup_init_early(void); | |
27 | extern int cgroup_init(void); | |
ddbcc7e8 | 28 | extern void cgroup_lock(void); |
84eea842 | 29 | extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
ddbcc7e8 | 30 | extern void cgroup_unlock(void); |
b4f48b63 PM |
31 | extern void cgroup_fork(struct task_struct *p); |
32 | extern void cgroup_fork_callbacks(struct task_struct *p); | |
817929ec | 33 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 34 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
35 | extern int cgroupstats_build(struct cgroupstats *stats, |
36 | struct dentry *dentry); | |
ddbcc7e8 | 37 | |
a424316c PM |
38 | extern struct file_operations proc_cgroup_operations; |
39 | ||
817929ec PM |
40 | /* Define the enumeration of all cgroup subsystems */ |
41 | #define SUBSYS(_x) _x ## _subsys_id, | |
42 | enum cgroup_subsys_id { | |
43 | #include <linux/cgroup_subsys.h> | |
44 | CGROUP_SUBSYS_COUNT | |
45 | }; | |
46 | #undef SUBSYS | |
47 | ||
ddbcc7e8 PM |
48 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
49 | struct cgroup_subsys_state { | |
50 | /* The cgroup that this subsystem is attached to. Useful | |
51 | * for subsystems that want to know about the cgroup | |
52 | * hierarchy structure */ | |
53 | struct cgroup *cgroup; | |
54 | ||
55 | /* State maintained by the cgroup system to allow | |
56 | * subsystems to be "busy". Should be accessed via css_get() | |
57 | * and css_put() */ | |
58 | ||
59 | atomic_t refcnt; | |
60 | ||
61 | unsigned long flags; | |
62 | }; | |
63 | ||
64 | /* bits in struct cgroup_subsys_state flags field */ | |
65 | enum { | |
66 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
67 | }; | |
68 | ||
69 | /* | |
70 | * Call css_get() to hold a reference on the cgroup; | |
71 | * | |
72 | */ | |
73 | ||
74 | static inline void css_get(struct cgroup_subsys_state *css) | |
75 | { | |
76 | /* We don't need to reference count the root state */ | |
77 | if (!test_bit(CSS_ROOT, &css->flags)) | |
78 | atomic_inc(&css->refcnt); | |
79 | } | |
80 | /* | |
81 | * css_put() should be called to release a reference taken by | |
82 | * css_get() | |
83 | */ | |
84 | ||
81a6a5cd | 85 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
86 | static inline void css_put(struct cgroup_subsys_state *css) |
87 | { | |
88 | if (!test_bit(CSS_ROOT, &css->flags)) | |
81a6a5cd | 89 | __css_put(css); |
ddbcc7e8 PM |
90 | } |
91 | ||
3116f0e3 PM |
92 | /* bits in struct cgroup flags field */ |
93 | enum { | |
94 | /* Control Group is dead */ | |
95 | CGRP_REMOVED, | |
96 | /* Control Group has previously had a child cgroup or a task, | |
97 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) */ | |
98 | CGRP_RELEASABLE, | |
99 | /* Control Group requires release notifications to userspace */ | |
100 | CGRP_NOTIFY_ON_RELEASE, | |
101 | }; | |
102 | ||
ddbcc7e8 PM |
103 | struct cgroup { |
104 | unsigned long flags; /* "unsigned long" so bitops work */ | |
105 | ||
106 | /* count users of this cgroup. >0 means busy, but doesn't | |
107 | * necessarily indicate the number of tasks in the | |
108 | * cgroup */ | |
109 | atomic_t count; | |
110 | ||
111 | /* | |
112 | * We link our 'sibling' struct into our parent's 'children'. | |
113 | * Our children link their 'sibling' into our 'children'. | |
114 | */ | |
115 | struct list_head sibling; /* my parent's children */ | |
116 | struct list_head children; /* my children */ | |
117 | ||
118 | struct cgroup *parent; /* my parent */ | |
119 | struct dentry *dentry; /* cgroup fs entry */ | |
120 | ||
121 | /* Private pointers for each registered subsystem */ | |
122 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
123 | ||
124 | struct cgroupfs_root *root; | |
125 | struct cgroup *top_cgroup; | |
817929ec PM |
126 | |
127 | /* | |
128 | * List of cg_cgroup_links pointing at css_sets with | |
129 | * tasks in this cgroup. Protected by css_set_lock | |
130 | */ | |
131 | struct list_head css_sets; | |
81a6a5cd PM |
132 | |
133 | /* | |
134 | * Linked list running through all cgroups that can | |
135 | * potentially be reaped by the release agent. Protected by | |
136 | * release_list_lock | |
137 | */ | |
138 | struct list_head release_list; | |
cc31edce PM |
139 | |
140 | /* pids_mutex protects the fields below */ | |
141 | struct rw_semaphore pids_mutex; | |
142 | /* Array of process ids in the cgroup */ | |
143 | pid_t *tasks_pids; | |
144 | /* How many files are using the current tasks_pids array */ | |
145 | int pids_use_count; | |
146 | /* Length of the current tasks_pids array */ | |
147 | int pids_length; | |
817929ec PM |
148 | }; |
149 | ||
150 | /* A css_set is a structure holding pointers to a set of | |
151 | * cgroup_subsys_state objects. This saves space in the task struct | |
152 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
153 | * list_add()/del() can bump the reference count on the entire | |
154 | * cgroup set for a task. | |
155 | */ | |
156 | ||
157 | struct css_set { | |
158 | ||
159 | /* Reference count */ | |
146aa1bd | 160 | atomic_t refcount; |
817929ec | 161 | |
472b1053 LZ |
162 | /* |
163 | * List running through all cgroup groups in the same hash | |
164 | * slot. Protected by css_set_lock | |
165 | */ | |
166 | struct hlist_node hlist; | |
167 | ||
817929ec PM |
168 | /* |
169 | * List running through all tasks using this cgroup | |
170 | * group. Protected by css_set_lock | |
171 | */ | |
172 | struct list_head tasks; | |
173 | ||
174 | /* | |
175 | * List of cg_cgroup_link objects on link chains from | |
176 | * cgroups referenced from this css_set. Protected by | |
177 | * css_set_lock | |
178 | */ | |
179 | struct list_head cg_links; | |
180 | ||
181 | /* | |
182 | * Set of subsystem states, one for each subsystem. This array | |
183 | * is immutable after creation apart from the init_css_set | |
184 | * during subsystem registration (at boot time). | |
185 | */ | |
186 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
ddbcc7e8 PM |
187 | }; |
188 | ||
91796569 PM |
189 | /* |
190 | * cgroup_map_cb is an abstract callback API for reporting map-valued | |
191 | * control files | |
192 | */ | |
193 | ||
194 | struct cgroup_map_cb { | |
195 | int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); | |
196 | void *state; | |
197 | }; | |
198 | ||
ddbcc7e8 PM |
199 | /* struct cftype: |
200 | * | |
201 | * The files in the cgroup filesystem mostly have a very simple read/write | |
202 | * handling, some common function will take care of it. Nevertheless some cases | |
203 | * (read tasks) are special and therefore I define this structure for every | |
204 | * kind of file. | |
205 | * | |
206 | * | |
207 | * When reading/writing to a file: | |
a043e3b2 | 208 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
ddbcc7e8 PM |
209 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
210 | */ | |
211 | ||
212 | #define MAX_CFTYPE_NAME 64 | |
213 | struct cftype { | |
214 | /* By convention, the name should begin with the name of the | |
215 | * subsystem, followed by a period */ | |
216 | char name[MAX_CFTYPE_NAME]; | |
217 | int private; | |
db3b1497 PM |
218 | |
219 | /* | |
220 | * If non-zero, defines the maximum length of string that can | |
221 | * be passed to write_string; defaults to 64 | |
222 | */ | |
223 | size_t max_write_len; | |
224 | ||
ce16b49d PM |
225 | int (*open)(struct inode *inode, struct file *file); |
226 | ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, | |
227 | struct file *file, | |
228 | char __user *buf, size_t nbytes, loff_t *ppos); | |
ddbcc7e8 | 229 | /* |
f4c753b7 | 230 | * read_u64() is a shortcut for the common case of returning a |
ddbcc7e8 PM |
231 | * single integer. Use it in place of read() |
232 | */ | |
ce16b49d | 233 | u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
e73d2c61 PM |
234 | /* |
235 | * read_s64() is a signed version of read_u64() | |
236 | */ | |
ce16b49d | 237 | s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
91796569 PM |
238 | /* |
239 | * read_map() is used for defining a map of key/value | |
240 | * pairs. It should call cb->fill(cb, key, value) for each | |
241 | * entry. The key/value pairs (and their ordering) should not | |
242 | * change between reboots. | |
243 | */ | |
ce16b49d PM |
244 | int (*read_map)(struct cgroup *cont, struct cftype *cft, |
245 | struct cgroup_map_cb *cb); | |
29486df3 SH |
246 | /* |
247 | * read_seq_string() is used for outputting a simple sequence | |
248 | * using seqfile. | |
249 | */ | |
ce16b49d PM |
250 | int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
251 | struct seq_file *m); | |
91796569 | 252 | |
ce16b49d PM |
253 | ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
254 | struct file *file, | |
255 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
256 | |
257 | /* | |
f4c753b7 | 258 | * write_u64() is a shortcut for the common case of accepting |
355e0c48 PM |
259 | * a single integer (as parsed by simple_strtoull) from |
260 | * userspace. Use in place of write(); return 0 or error. | |
261 | */ | |
ce16b49d | 262 | int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
e73d2c61 PM |
263 | /* |
264 | * write_s64() is a signed version of write_u64() | |
265 | */ | |
ce16b49d | 266 | int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
355e0c48 | 267 | |
db3b1497 PM |
268 | /* |
269 | * write_string() is passed a nul-terminated kernelspace | |
270 | * buffer of maximum length determined by max_write_len. | |
271 | * Returns 0 or -ve error code. | |
272 | */ | |
273 | int (*write_string)(struct cgroup *cgrp, struct cftype *cft, | |
274 | const char *buffer); | |
d447ea2f PE |
275 | /* |
276 | * trigger() callback can be used to get some kick from the | |
277 | * userspace, when the actual string written is not important | |
278 | * at all. The private field can be used to determine the | |
279 | * kick type for multiplexing. | |
280 | */ | |
281 | int (*trigger)(struct cgroup *cgrp, unsigned int event); | |
282 | ||
ce16b49d | 283 | int (*release)(struct inode *inode, struct file *file); |
ddbcc7e8 PM |
284 | }; |
285 | ||
31a7df01 CW |
286 | struct cgroup_scanner { |
287 | struct cgroup *cg; | |
288 | int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); | |
289 | void (*process_task)(struct task_struct *p, | |
290 | struct cgroup_scanner *scan); | |
291 | struct ptr_heap *heap; | |
292 | }; | |
293 | ||
ddbcc7e8 PM |
294 | /* Add a new file to the given cgroup directory. Should only be |
295 | * called by subsystems from within a populate() method */ | |
ffd2d883 | 296 | int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, |
ddbcc7e8 PM |
297 | const struct cftype *cft); |
298 | ||
299 | /* Add a set of new files to the given cgroup directory. Should | |
300 | * only be called by subsystems from within a populate() method */ | |
ffd2d883 | 301 | int cgroup_add_files(struct cgroup *cgrp, |
ddbcc7e8 PM |
302 | struct cgroup_subsys *subsys, |
303 | const struct cftype cft[], | |
304 | int count); | |
305 | ||
ffd2d883 | 306 | int cgroup_is_removed(const struct cgroup *cgrp); |
ddbcc7e8 | 307 | |
ffd2d883 | 308 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
ddbcc7e8 | 309 | |
ffd2d883 | 310 | int cgroup_task_count(const struct cgroup *cgrp); |
bbcb81d0 | 311 | |
ddbcc7e8 | 312 | /* Return true if the cgroup is a descendant of the current cgroup */ |
ffd2d883 | 313 | int cgroup_is_descendant(const struct cgroup *cgrp); |
ddbcc7e8 PM |
314 | |
315 | /* Control Group subsystem type. See Documentation/cgroups.txt for details */ | |
316 | ||
317 | struct cgroup_subsys { | |
318 | struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, | |
ffd2d883 LZ |
319 | struct cgroup *cgrp); |
320 | void (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
321 | void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
ddbcc7e8 | 322 | int (*can_attach)(struct cgroup_subsys *ss, |
ffd2d883 LZ |
323 | struct cgroup *cgrp, struct task_struct *tsk); |
324 | void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
325 | struct cgroup *old_cgrp, struct task_struct *tsk); | |
ddbcc7e8 PM |
326 | void (*fork)(struct cgroup_subsys *ss, struct task_struct *task); |
327 | void (*exit)(struct cgroup_subsys *ss, struct task_struct *task); | |
328 | int (*populate)(struct cgroup_subsys *ss, | |
ffd2d883 LZ |
329 | struct cgroup *cgrp); |
330 | void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
ddbcc7e8 | 331 | void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
cf475ad2 BS |
332 | /* |
333 | * This routine is called with the task_lock of mm->owner held | |
334 | */ | |
335 | void (*mm_owner_changed)(struct cgroup_subsys *ss, | |
336 | struct cgroup *old, | |
9363b9f2 BS |
337 | struct cgroup *new, |
338 | struct task_struct *p); | |
ddbcc7e8 PM |
339 | int subsys_id; |
340 | int active; | |
8bab8dde | 341 | int disabled; |
ddbcc7e8 PM |
342 | int early_init; |
343 | #define MAX_CGROUP_TYPE_NAMELEN 32 | |
344 | const char *name; | |
345 | ||
346 | /* Protected by RCU */ | |
347 | struct cgroupfs_root *root; | |
348 | ||
349 | struct list_head sibling; | |
ddbcc7e8 PM |
350 | }; |
351 | ||
352 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
353 | #include <linux/cgroup_subsys.h> | |
354 | #undef SUBSYS | |
355 | ||
356 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
ffd2d883 | 357 | struct cgroup *cgrp, int subsys_id) |
ddbcc7e8 | 358 | { |
ffd2d883 | 359 | return cgrp->subsys[subsys_id]; |
ddbcc7e8 PM |
360 | } |
361 | ||
362 | static inline struct cgroup_subsys_state *task_subsys_state( | |
363 | struct task_struct *task, int subsys_id) | |
364 | { | |
817929ec | 365 | return rcu_dereference(task->cgroups->subsys[subsys_id]); |
ddbcc7e8 PM |
366 | } |
367 | ||
368 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
369 | int subsys_id) | |
370 | { | |
371 | return task_subsys_state(task, subsys_id)->cgroup; | |
372 | } | |
373 | ||
e885dcde SH |
374 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss, |
375 | char *nodename); | |
697f4161 | 376 | |
817929ec PM |
377 | /* A cgroup_iter should be treated as an opaque object */ |
378 | struct cgroup_iter { | |
379 | struct list_head *cg_link; | |
380 | struct list_head *task; | |
381 | }; | |
382 | ||
383 | /* To iterate across the tasks in a cgroup: | |
384 | * | |
385 | * 1) call cgroup_iter_start to intialize an iterator | |
386 | * | |
387 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
388 | * returns NULL or until you want to end the iteration | |
389 | * | |
390 | * 3) call cgroup_iter_end() to destroy the iterator. | |
31a7df01 CW |
391 | * |
392 | * Or, call cgroup_scan_tasks() to iterate through every task in a cpuset. | |
393 | * - cgroup_scan_tasks() holds the css_set_lock when calling the test_task() | |
394 | * callback, but not while calling the process_task() callback. | |
817929ec | 395 | */ |
ffd2d883 LZ |
396 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
397 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, | |
817929ec | 398 | struct cgroup_iter *it); |
ffd2d883 | 399 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
31a7df01 | 400 | int cgroup_scan_tasks(struct cgroup_scanner *scan); |
956db3ca | 401 | int cgroup_attach_task(struct cgroup *, struct task_struct *); |
817929ec | 402 | |
886465f4 PM |
403 | void cgroup_mm_owner_callbacks(struct task_struct *old, |
404 | struct task_struct *new); | |
405 | ||
ddbcc7e8 PM |
406 | #else /* !CONFIG_CGROUPS */ |
407 | ||
408 | static inline int cgroup_init_early(void) { return 0; } | |
409 | static inline int cgroup_init(void) { return 0; } | |
b4f48b63 PM |
410 | static inline void cgroup_fork(struct task_struct *p) {} |
411 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 412 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 413 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
414 | |
415 | static inline void cgroup_lock(void) {} | |
416 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
417 | static inline int cgroupstats_build(struct cgroupstats *stats, |
418 | struct dentry *dentry) | |
419 | { | |
420 | return -EINVAL; | |
421 | } | |
ddbcc7e8 | 422 | |
886465f4 PM |
423 | static inline void cgroup_mm_owner_callbacks(struct task_struct *old, |
424 | struct task_struct *new) {} | |
425 | ||
ddbcc7e8 PM |
426 | #endif /* !CONFIG_CGROUPS */ |
427 | ||
428 | #endif /* _LINUX_CGROUP_H */ |