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