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