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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> | |
12 | #include <linux/kref.h> | |
13 | #include <linux/cpumask.h> | |
14 | #include <linux/nodemask.h> | |
15 | #include <linux/rcupdate.h> | |
846c7bb0 | 16 | #include <linux/cgroupstats.h> |
ddbcc7e8 PM |
17 | |
18 | #ifdef CONFIG_CGROUPS | |
19 | ||
20 | struct cgroupfs_root; | |
21 | struct cgroup_subsys; | |
22 | struct inode; | |
23 | ||
24 | extern int cgroup_init_early(void); | |
25 | extern int cgroup_init(void); | |
26 | extern void cgroup_init_smp(void); | |
27 | extern void cgroup_lock(void); | |
28 | extern void cgroup_unlock(void); | |
b4f48b63 PM |
29 | extern void cgroup_fork(struct task_struct *p); |
30 | extern void cgroup_fork_callbacks(struct task_struct *p); | |
817929ec | 31 | extern void cgroup_post_fork(struct task_struct *p); |
b4f48b63 | 32 | extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
846c7bb0 BS |
33 | extern int cgroupstats_build(struct cgroupstats *stats, |
34 | struct dentry *dentry); | |
ddbcc7e8 | 35 | |
a424316c PM |
36 | extern struct file_operations proc_cgroup_operations; |
37 | ||
817929ec PM |
38 | /* Define the enumeration of all cgroup subsystems */ |
39 | #define SUBSYS(_x) _x ## _subsys_id, | |
40 | enum cgroup_subsys_id { | |
41 | #include <linux/cgroup_subsys.h> | |
42 | CGROUP_SUBSYS_COUNT | |
43 | }; | |
44 | #undef SUBSYS | |
45 | ||
ddbcc7e8 PM |
46 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
47 | struct cgroup_subsys_state { | |
48 | /* The cgroup that this subsystem is attached to. Useful | |
49 | * for subsystems that want to know about the cgroup | |
50 | * hierarchy structure */ | |
51 | struct cgroup *cgroup; | |
52 | ||
53 | /* State maintained by the cgroup system to allow | |
54 | * subsystems to be "busy". Should be accessed via css_get() | |
55 | * and css_put() */ | |
56 | ||
57 | atomic_t refcnt; | |
58 | ||
59 | unsigned long flags; | |
60 | }; | |
61 | ||
62 | /* bits in struct cgroup_subsys_state flags field */ | |
63 | enum { | |
64 | CSS_ROOT, /* This CSS is the root of the subsystem */ | |
65 | }; | |
66 | ||
67 | /* | |
68 | * Call css_get() to hold a reference on the cgroup; | |
69 | * | |
70 | */ | |
71 | ||
72 | static inline void css_get(struct cgroup_subsys_state *css) | |
73 | { | |
74 | /* We don't need to reference count the root state */ | |
75 | if (!test_bit(CSS_ROOT, &css->flags)) | |
76 | atomic_inc(&css->refcnt); | |
77 | } | |
78 | /* | |
79 | * css_put() should be called to release a reference taken by | |
80 | * css_get() | |
81 | */ | |
82 | ||
81a6a5cd | 83 | extern void __css_put(struct cgroup_subsys_state *css); |
ddbcc7e8 PM |
84 | static inline void css_put(struct cgroup_subsys_state *css) |
85 | { | |
86 | if (!test_bit(CSS_ROOT, &css->flags)) | |
81a6a5cd | 87 | __css_put(css); |
ddbcc7e8 PM |
88 | } |
89 | ||
90 | struct cgroup { | |
91 | unsigned long flags; /* "unsigned long" so bitops work */ | |
92 | ||
93 | /* count users of this cgroup. >0 means busy, but doesn't | |
94 | * necessarily indicate the number of tasks in the | |
95 | * cgroup */ | |
96 | atomic_t count; | |
97 | ||
98 | /* | |
99 | * We link our 'sibling' struct into our parent's 'children'. | |
100 | * Our children link their 'sibling' into our 'children'. | |
101 | */ | |
102 | struct list_head sibling; /* my parent's children */ | |
103 | struct list_head children; /* my children */ | |
104 | ||
105 | struct cgroup *parent; /* my parent */ | |
106 | struct dentry *dentry; /* cgroup fs entry */ | |
107 | ||
108 | /* Private pointers for each registered subsystem */ | |
109 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
110 | ||
111 | struct cgroupfs_root *root; | |
112 | struct cgroup *top_cgroup; | |
817929ec PM |
113 | |
114 | /* | |
115 | * List of cg_cgroup_links pointing at css_sets with | |
116 | * tasks in this cgroup. Protected by css_set_lock | |
117 | */ | |
118 | struct list_head css_sets; | |
81a6a5cd PM |
119 | |
120 | /* | |
121 | * Linked list running through all cgroups that can | |
122 | * potentially be reaped by the release agent. Protected by | |
123 | * release_list_lock | |
124 | */ | |
125 | struct list_head release_list; | |
817929ec PM |
126 | }; |
127 | ||
128 | /* A css_set is a structure holding pointers to a set of | |
129 | * cgroup_subsys_state objects. This saves space in the task struct | |
130 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
131 | * list_add()/del() can bump the reference count on the entire | |
132 | * cgroup set for a task. | |
133 | */ | |
134 | ||
135 | struct css_set { | |
136 | ||
137 | /* Reference count */ | |
138 | struct kref ref; | |
139 | ||
140 | /* | |
141 | * List running through all cgroup groups. Protected by | |
142 | * css_set_lock | |
143 | */ | |
144 | struct list_head list; | |
145 | ||
146 | /* | |
147 | * List running through all tasks using this cgroup | |
148 | * group. Protected by css_set_lock | |
149 | */ | |
150 | struct list_head tasks; | |
151 | ||
152 | /* | |
153 | * List of cg_cgroup_link objects on link chains from | |
154 | * cgroups referenced from this css_set. Protected by | |
155 | * css_set_lock | |
156 | */ | |
157 | struct list_head cg_links; | |
158 | ||
159 | /* | |
160 | * Set of subsystem states, one for each subsystem. This array | |
161 | * is immutable after creation apart from the init_css_set | |
162 | * during subsystem registration (at boot time). | |
163 | */ | |
164 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; | |
165 | ||
ddbcc7e8 PM |
166 | }; |
167 | ||
168 | /* struct cftype: | |
169 | * | |
170 | * The files in the cgroup filesystem mostly have a very simple read/write | |
171 | * handling, some common function will take care of it. Nevertheless some cases | |
172 | * (read tasks) are special and therefore I define this structure for every | |
173 | * kind of file. | |
174 | * | |
175 | * | |
176 | * When reading/writing to a file: | |
177 | * - the cgroup to use in file->f_dentry->d_parent->d_fsdata | |
178 | * - the 'cftype' of the file is file->f_dentry->d_fsdata | |
179 | */ | |
180 | ||
181 | #define MAX_CFTYPE_NAME 64 | |
182 | struct cftype { | |
183 | /* By convention, the name should begin with the name of the | |
184 | * subsystem, followed by a period */ | |
185 | char name[MAX_CFTYPE_NAME]; | |
186 | int private; | |
187 | int (*open) (struct inode *inode, struct file *file); | |
188 | ssize_t (*read) (struct cgroup *cont, struct cftype *cft, | |
189 | struct file *file, | |
190 | char __user *buf, size_t nbytes, loff_t *ppos); | |
191 | /* | |
192 | * read_uint() is a shortcut for the common case of returning a | |
193 | * single integer. Use it in place of read() | |
194 | */ | |
195 | u64 (*read_uint) (struct cgroup *cont, struct cftype *cft); | |
196 | ssize_t (*write) (struct cgroup *cont, struct cftype *cft, | |
197 | struct file *file, | |
198 | const char __user *buf, size_t nbytes, loff_t *ppos); | |
355e0c48 PM |
199 | |
200 | /* | |
201 | * write_uint() is a shortcut for the common case of accepting | |
202 | * a single integer (as parsed by simple_strtoull) from | |
203 | * userspace. Use in place of write(); return 0 or error. | |
204 | */ | |
205 | int (*write_uint) (struct cgroup *cont, struct cftype *cft, u64 val); | |
206 | ||
ddbcc7e8 PM |
207 | int (*release) (struct inode *inode, struct file *file); |
208 | }; | |
209 | ||
210 | /* Add a new file to the given cgroup directory. Should only be | |
211 | * called by subsystems from within a populate() method */ | |
212 | int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys, | |
213 | const struct cftype *cft); | |
214 | ||
215 | /* Add a set of new files to the given cgroup directory. Should | |
216 | * only be called by subsystems from within a populate() method */ | |
217 | int cgroup_add_files(struct cgroup *cont, | |
218 | struct cgroup_subsys *subsys, | |
219 | const struct cftype cft[], | |
220 | int count); | |
221 | ||
222 | int cgroup_is_removed(const struct cgroup *cont); | |
223 | ||
224 | int cgroup_path(const struct cgroup *cont, char *buf, int buflen); | |
225 | ||
817929ec | 226 | int cgroup_task_count(const struct cgroup *cont); |
bbcb81d0 | 227 | |
ddbcc7e8 PM |
228 | /* Return true if the cgroup is a descendant of the current cgroup */ |
229 | int cgroup_is_descendant(const struct cgroup *cont); | |
230 | ||
231 | /* Control Group subsystem type. See Documentation/cgroups.txt for details */ | |
232 | ||
233 | struct cgroup_subsys { | |
234 | struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, | |
235 | struct cgroup *cont); | |
236 | void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont); | |
237 | int (*can_attach)(struct cgroup_subsys *ss, | |
238 | struct cgroup *cont, struct task_struct *tsk); | |
239 | void (*attach)(struct cgroup_subsys *ss, struct cgroup *cont, | |
240 | struct cgroup *old_cont, struct task_struct *tsk); | |
241 | void (*fork)(struct cgroup_subsys *ss, struct task_struct *task); | |
242 | void (*exit)(struct cgroup_subsys *ss, struct task_struct *task); | |
243 | int (*populate)(struct cgroup_subsys *ss, | |
244 | struct cgroup *cont); | |
697f4161 | 245 | void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cont); |
ddbcc7e8 PM |
246 | void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
247 | int subsys_id; | |
248 | int active; | |
249 | int early_init; | |
250 | #define MAX_CGROUP_TYPE_NAMELEN 32 | |
251 | const char *name; | |
252 | ||
253 | /* Protected by RCU */ | |
254 | struct cgroupfs_root *root; | |
255 | ||
256 | struct list_head sibling; | |
257 | ||
258 | void *private; | |
259 | }; | |
260 | ||
261 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; | |
262 | #include <linux/cgroup_subsys.h> | |
263 | #undef SUBSYS | |
264 | ||
265 | static inline struct cgroup_subsys_state *cgroup_subsys_state( | |
266 | struct cgroup *cont, int subsys_id) | |
267 | { | |
268 | return cont->subsys[subsys_id]; | |
269 | } | |
270 | ||
271 | static inline struct cgroup_subsys_state *task_subsys_state( | |
272 | struct task_struct *task, int subsys_id) | |
273 | { | |
817929ec | 274 | return rcu_dereference(task->cgroups->subsys[subsys_id]); |
ddbcc7e8 PM |
275 | } |
276 | ||
277 | static inline struct cgroup* task_cgroup(struct task_struct *task, | |
278 | int subsys_id) | |
279 | { | |
280 | return task_subsys_state(task, subsys_id)->cgroup; | |
281 | } | |
282 | ||
283 | int cgroup_path(const struct cgroup *cont, char *buf, int buflen); | |
284 | ||
697f4161 PM |
285 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss); |
286 | ||
817929ec PM |
287 | /* A cgroup_iter should be treated as an opaque object */ |
288 | struct cgroup_iter { | |
289 | struct list_head *cg_link; | |
290 | struct list_head *task; | |
291 | }; | |
292 | ||
293 | /* To iterate across the tasks in a cgroup: | |
294 | * | |
295 | * 1) call cgroup_iter_start to intialize an iterator | |
296 | * | |
297 | * 2) call cgroup_iter_next() to retrieve member tasks until it | |
298 | * returns NULL or until you want to end the iteration | |
299 | * | |
300 | * 3) call cgroup_iter_end() to destroy the iterator. | |
301 | */ | |
302 | void cgroup_iter_start(struct cgroup *cont, struct cgroup_iter *it); | |
303 | struct task_struct *cgroup_iter_next(struct cgroup *cont, | |
304 | struct cgroup_iter *it); | |
305 | void cgroup_iter_end(struct cgroup *cont, struct cgroup_iter *it); | |
306 | ||
ddbcc7e8 PM |
307 | #else /* !CONFIG_CGROUPS */ |
308 | ||
309 | static inline int cgroup_init_early(void) { return 0; } | |
310 | static inline int cgroup_init(void) { return 0; } | |
311 | static inline void cgroup_init_smp(void) {} | |
b4f48b63 PM |
312 | static inline void cgroup_fork(struct task_struct *p) {} |
313 | static inline void cgroup_fork_callbacks(struct task_struct *p) {} | |
817929ec | 314 | static inline void cgroup_post_fork(struct task_struct *p) {} |
b4f48b63 | 315 | static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
ddbcc7e8 PM |
316 | |
317 | static inline void cgroup_lock(void) {} | |
318 | static inline void cgroup_unlock(void) {} | |
846c7bb0 BS |
319 | static inline int cgroupstats_build(struct cgroupstats *stats, |
320 | struct dentry *dentry) | |
321 | { | |
322 | return -EINVAL; | |
323 | } | |
ddbcc7e8 PM |
324 | |
325 | #endif /* !CONFIG_CGROUPS */ | |
326 | ||
327 | #endif /* _LINUX_CGROUP_H */ |