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