Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 1 | /* |
| 2 | * linux/cgroup-defs.h - basic definitions for cgroup |
| 3 | * |
| 4 | * This file provides basic type and interface. Include this file directly |
| 5 | * only if necessary to avoid cyclic dependencies. |
| 6 | */ |
| 7 | #ifndef _LINUX_CGROUP_DEFS_H |
| 8 | #define _LINUX_CGROUP_DEFS_H |
| 9 | |
| 10 | #include <linux/limits.h> |
| 11 | #include <linux/list.h> |
| 12 | #include <linux/idr.h> |
| 13 | #include <linux/wait.h> |
| 14 | #include <linux/mutex.h> |
| 15 | #include <linux/rcupdate.h> |
| 16 | #include <linux/percpu-refcount.h> |
Tejun Heo | 7d7efec | 2015-05-13 16:35:16 -0400 | [diff] [blame] | 17 | #include <linux/percpu-rwsem.h> |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 18 | #include <linux/workqueue.h> |
| 19 | |
| 20 | #ifdef CONFIG_CGROUPS |
| 21 | |
| 22 | struct cgroup; |
| 23 | struct cgroup_root; |
| 24 | struct cgroup_subsys; |
| 25 | struct cgroup_taskset; |
| 26 | struct kernfs_node; |
| 27 | struct kernfs_ops; |
| 28 | struct kernfs_open_file; |
Arnd Bergmann | c80ef9e | 2015-05-29 10:52:59 +0200 | [diff] [blame] | 29 | struct seq_file; |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 30 | |
| 31 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
| 32 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
| 33 | #define MAX_CFTYPE_NAME 64 |
| 34 | |
| 35 | /* define the enumeration of all cgroup subsystems */ |
| 36 | #define SUBSYS(_x) _x ## _cgrp_id, |
| 37 | enum cgroup_subsys_id { |
| 38 | #include <linux/cgroup_subsys.h> |
| 39 | CGROUP_SUBSYS_COUNT, |
| 40 | }; |
| 41 | #undef SUBSYS |
| 42 | |
| 43 | /* bits in struct cgroup_subsys_state flags field */ |
| 44 | enum { |
| 45 | CSS_NO_REF = (1 << 0), /* no reference counting for this css */ |
| 46 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
| 47 | CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ |
| 48 | }; |
| 49 | |
| 50 | /* bits in struct cgroup flags field */ |
| 51 | enum { |
| 52 | /* Control Group requires release notifications to userspace */ |
| 53 | CGRP_NOTIFY_ON_RELEASE, |
| 54 | /* |
| 55 | * Clone the parent's configuration when creating a new child |
| 56 | * cpuset cgroup. For historical reasons, this option can be |
| 57 | * specified at mount time and thus is implemented here. |
| 58 | */ |
| 59 | CGRP_CPUSET_CLONE_CHILDREN, |
| 60 | }; |
| 61 | |
| 62 | /* cgroup_root->flags */ |
| 63 | enum { |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 64 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
| 65 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ |
| 66 | }; |
| 67 | |
| 68 | /* cftype->flags */ |
| 69 | enum { |
| 70 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ |
| 71 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ |
| 72 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
Tejun Heo | 7dbdb19 | 2015-09-18 17:54:23 -0400 | [diff] [blame] | 73 | CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 74 | |
| 75 | /* internal flags, do not use outside cgroup core proper */ |
| 76 | __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ |
| 77 | __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ |
| 78 | }; |
| 79 | |
| 80 | /* |
Tejun Heo | 6f60ead | 2015-09-18 17:54:23 -0400 | [diff] [blame] | 81 | * cgroup_file is the handle for a file instance created in a cgroup which |
| 82 | * is used, for example, to generate file changed notifications. This can |
| 83 | * be obtained by setting cftype->file_offset. |
| 84 | */ |
| 85 | struct cgroup_file { |
| 86 | /* do not access any fields from outside cgroup core */ |
Tejun Heo | 6f60ead | 2015-09-18 17:54:23 -0400 | [diff] [blame] | 87 | struct kernfs_node *kn; |
| 88 | }; |
| 89 | |
| 90 | /* |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 91 | * Per-subsystem/per-cgroup state maintained by the system. This is the |
| 92 | * fundamental structural building block that controllers deal with. |
| 93 | * |
| 94 | * Fields marked with "PI:" are public and immutable and may be accessed |
| 95 | * directly without synchronization. |
| 96 | */ |
| 97 | struct cgroup_subsys_state { |
| 98 | /* PI: the cgroup that this css is attached to */ |
| 99 | struct cgroup *cgroup; |
| 100 | |
| 101 | /* PI: the cgroup subsystem that this css is attached to */ |
| 102 | struct cgroup_subsys *ss; |
| 103 | |
| 104 | /* reference count - access via css_[try]get() and css_put() */ |
| 105 | struct percpu_ref refcnt; |
| 106 | |
| 107 | /* PI: the parent css */ |
| 108 | struct cgroup_subsys_state *parent; |
| 109 | |
| 110 | /* siblings list anchored at the parent's ->children */ |
| 111 | struct list_head sibling; |
| 112 | struct list_head children; |
| 113 | |
| 114 | /* |
| 115 | * PI: Subsys-unique ID. 0 is unused and root is always 1. The |
| 116 | * matching css can be looked up using css_from_id(). |
| 117 | */ |
| 118 | int id; |
| 119 | |
| 120 | unsigned int flags; |
| 121 | |
| 122 | /* |
| 123 | * Monotonically increasing unique serial number which defines a |
| 124 | * uniform order among all csses. It's guaranteed that all |
| 125 | * ->children lists are in the ascending order of ->serial_nr and |
| 126 | * used to allow interrupting and resuming iterations. |
| 127 | */ |
| 128 | u64 serial_nr; |
| 129 | |
Tejun Heo | aa226ff | 2016-01-21 15:31:11 -0500 | [diff] [blame] | 130 | /* |
| 131 | * Incremented by online self and children. Used to guarantee that |
| 132 | * parents are not offlined before their children. |
| 133 | */ |
| 134 | atomic_t online_cnt; |
| 135 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 136 | /* percpu_ref killing and RCU release */ |
| 137 | struct rcu_head rcu_head; |
| 138 | struct work_struct destroy_work; |
| 139 | }; |
| 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 cgroup |
| 146 | * set for a task. |
| 147 | */ |
| 148 | struct css_set { |
| 149 | /* Reference count */ |
| 150 | atomic_t refcount; |
| 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 | * Lists running through all tasks using this cgroup group. |
| 160 | * mg_tasks lists tasks which belong to this cset but are in the |
| 161 | * process of being migrated out or in. Protected by |
| 162 | * css_set_rwsem, but, during migration, once tasks are moved to |
| 163 | * mg_tasks, it can be read safely while holding cgroup_mutex. |
| 164 | */ |
| 165 | struct list_head tasks; |
| 166 | struct list_head mg_tasks; |
| 167 | |
| 168 | /* |
| 169 | * List of cgrp_cset_links pointing at cgroups referenced from this |
| 170 | * css_set. Protected by css_set_lock. |
| 171 | */ |
| 172 | struct list_head cgrp_links; |
| 173 | |
| 174 | /* the default cgroup associated with this css_set */ |
| 175 | struct cgroup *dfl_cgrp; |
| 176 | |
| 177 | /* |
| 178 | * Set of subsystem states, one for each subsystem. This array is |
| 179 | * immutable after creation apart from the init_css_set during |
| 180 | * subsystem registration (at boot time). |
| 181 | */ |
| 182 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
| 183 | |
| 184 | /* |
| 185 | * List of csets participating in the on-going migration either as |
| 186 | * source or destination. Protected by cgroup_mutex. |
| 187 | */ |
| 188 | struct list_head mg_preload_node; |
| 189 | struct list_head mg_node; |
| 190 | |
| 191 | /* |
| 192 | * If this cset is acting as the source of migration the following |
| 193 | * two fields are set. mg_src_cgrp is the source cgroup of the |
| 194 | * on-going migration and mg_dst_cset is the destination cset the |
| 195 | * target tasks on this cset should be migrated to. Protected by |
| 196 | * cgroup_mutex. |
| 197 | */ |
| 198 | struct cgroup *mg_src_cgrp; |
| 199 | struct css_set *mg_dst_cset; |
| 200 | |
| 201 | /* |
| 202 | * On the default hierarhcy, ->subsys[ssid] may point to a css |
| 203 | * attached to an ancestor instead of the cgroup this css_set is |
| 204 | * associated with. The following node is anchored at |
| 205 | * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to |
| 206 | * iterate through all css's attached to a given cgroup. |
| 207 | */ |
| 208 | struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; |
| 209 | |
Tejun Heo | ed27b9f | 2015-10-15 16:41:52 -0400 | [diff] [blame] | 210 | /* all css_task_iters currently walking this cset */ |
| 211 | struct list_head task_iters; |
| 212 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 213 | /* For RCU-protected deletion */ |
| 214 | struct rcu_head rcu_head; |
| 215 | }; |
| 216 | |
| 217 | struct cgroup { |
| 218 | /* self css with NULL ->ss, points back to this cgroup */ |
| 219 | struct cgroup_subsys_state self; |
| 220 | |
| 221 | unsigned long flags; /* "unsigned long" so bitops work */ |
| 222 | |
| 223 | /* |
| 224 | * idr allocated in-hierarchy ID. |
| 225 | * |
| 226 | * ID 0 is not used, the ID of the root cgroup is always 1, and a |
| 227 | * new cgroup will be assigned with a smallest available ID. |
| 228 | * |
| 229 | * Allocating/Removing ID must be protected by cgroup_mutex. |
| 230 | */ |
| 231 | int id; |
| 232 | |
| 233 | /* |
Tejun Heo | b11cfb5 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 234 | * The depth this cgroup is at. The root is at depth zero and each |
| 235 | * step down the hierarchy increments the level. This along with |
| 236 | * ancestor_ids[] can determine whether a given cgroup is a |
| 237 | * descendant of another without traversing the hierarchy. |
| 238 | */ |
| 239 | int level; |
| 240 | |
| 241 | /* |
Tejun Heo | 0de0942 | 2015-10-15 16:41:49 -0400 | [diff] [blame] | 242 | * Each non-empty css_set associated with this cgroup contributes |
| 243 | * one to populated_cnt. All children with non-zero popuplated_cnt |
| 244 | * of their own contribute one. The count is zero iff there's no |
| 245 | * task in this cgroup or its subtree. |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 246 | */ |
| 247 | int populated_cnt; |
| 248 | |
| 249 | struct kernfs_node *kn; /* cgroup kernfs entry */ |
Tejun Heo | 6f60ead | 2015-09-18 17:54:23 -0400 | [diff] [blame] | 250 | struct cgroup_file procs_file; /* handle for "cgroup.procs" */ |
| 251 | struct cgroup_file events_file; /* handle for "cgroup.events" */ |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 252 | |
| 253 | /* |
| 254 | * The bitmask of subsystems enabled on the child cgroups. |
| 255 | * ->subtree_control is the one configured through |
Tejun Heo | 8699b77 | 2016-02-22 22:25:46 -0500 | [diff] [blame] | 256 | * "cgroup.subtree_control" while ->child_ss_mask is the effective |
| 257 | * one which may have more subsystems enabled. Controller knobs |
| 258 | * are made available iff it's enabled in ->subtree_control. |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 259 | */ |
Tejun Heo | 8699b77 | 2016-02-22 22:25:46 -0500 | [diff] [blame] | 260 | unsigned long subtree_control; |
| 261 | unsigned long subtree_ss_mask; |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 262 | |
| 263 | /* Private pointers for each registered subsystem */ |
| 264 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; |
| 265 | |
| 266 | struct cgroup_root *root; |
| 267 | |
| 268 | /* |
| 269 | * List of cgrp_cset_links pointing at css_sets with tasks in this |
| 270 | * cgroup. Protected by css_set_lock. |
| 271 | */ |
| 272 | struct list_head cset_links; |
| 273 | |
| 274 | /* |
| 275 | * On the default hierarchy, a css_set for a cgroup with some |
| 276 | * susbsys disabled will point to css's which are associated with |
| 277 | * the closest ancestor which has the subsys enabled. The |
| 278 | * following lists all css_sets which point to this cgroup's css |
| 279 | * for the given subsystem. |
| 280 | */ |
| 281 | struct list_head e_csets[CGROUP_SUBSYS_COUNT]; |
| 282 | |
| 283 | /* |
| 284 | * list of pidlists, up to two for each namespace (one for procs, one |
| 285 | * for tasks); created on demand. |
| 286 | */ |
| 287 | struct list_head pidlists; |
| 288 | struct mutex pidlist_mutex; |
| 289 | |
| 290 | /* used to wait for offlining of csses */ |
| 291 | wait_queue_head_t offline_waitq; |
| 292 | |
| 293 | /* used to schedule release agent */ |
| 294 | struct work_struct release_agent_work; |
Tejun Heo | b11cfb5 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 295 | |
| 296 | /* ids of the ancestors at each level including self */ |
| 297 | int ancestor_ids[]; |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 298 | }; |
| 299 | |
| 300 | /* |
| 301 | * A cgroup_root represents the root of a cgroup hierarchy, and may be |
| 302 | * associated with a kernfs_root to form an active hierarchy. This is |
| 303 | * internal to cgroup core. Don't access directly from controllers. |
| 304 | */ |
| 305 | struct cgroup_root { |
| 306 | struct kernfs_root *kf_root; |
| 307 | |
| 308 | /* The bitmask of subsystems attached to this hierarchy */ |
| 309 | unsigned int subsys_mask; |
| 310 | |
| 311 | /* Unique id for this hierarchy. */ |
| 312 | int hierarchy_id; |
| 313 | |
| 314 | /* The root cgroup. Root is destroyed on its release. */ |
| 315 | struct cgroup cgrp; |
| 316 | |
Tejun Heo | b11cfb5 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 317 | /* for cgrp->ancestor_ids[0] */ |
| 318 | int cgrp_ancestor_id_storage; |
| 319 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 320 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
| 321 | atomic_t nr_cgrps; |
| 322 | |
| 323 | /* A list running through the active hierarchies */ |
| 324 | struct list_head root_list; |
| 325 | |
| 326 | /* Hierarchy-specific flags */ |
| 327 | unsigned int flags; |
| 328 | |
| 329 | /* IDs for cgroups in this hierarchy */ |
| 330 | struct idr cgroup_idr; |
| 331 | |
| 332 | /* The path to use for release notifications. */ |
| 333 | char release_agent_path[PATH_MAX]; |
| 334 | |
| 335 | /* The name for this hierarchy - may be empty */ |
| 336 | char name[MAX_CGROUP_ROOT_NAMELEN]; |
| 337 | }; |
| 338 | |
| 339 | /* |
| 340 | * struct cftype: handler definitions for cgroup control files |
| 341 | * |
| 342 | * When reading/writing to a file: |
| 343 | * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata |
| 344 | * - the 'cftype' of the file is file->f_path.dentry->d_fsdata |
| 345 | */ |
| 346 | struct cftype { |
| 347 | /* |
| 348 | * By convention, the name should begin with the name of the |
| 349 | * subsystem, followed by a period. Zero length string indicates |
| 350 | * end of cftype array. |
| 351 | */ |
| 352 | char name[MAX_CFTYPE_NAME]; |
Tejun Heo | 731a981 | 2015-08-11 13:35:42 -0400 | [diff] [blame] | 353 | unsigned long private; |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 354 | |
| 355 | /* |
| 356 | * The maximum length of string, excluding trailing nul, that can |
| 357 | * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. |
| 358 | */ |
| 359 | size_t max_write_len; |
| 360 | |
| 361 | /* CFTYPE_* flags */ |
| 362 | unsigned int flags; |
| 363 | |
| 364 | /* |
Tejun Heo | 6f60ead | 2015-09-18 17:54:23 -0400 | [diff] [blame] | 365 | * If non-zero, should contain the offset from the start of css to |
| 366 | * a struct cgroup_file field. cgroup will record the handle of |
| 367 | * the created file into it. The recorded handle can be used as |
| 368 | * long as the containing css remains accessible. |
| 369 | */ |
| 370 | unsigned int file_offset; |
| 371 | |
| 372 | /* |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 373 | * Fields used for internal bookkeeping. Initialized automatically |
| 374 | * during registration. |
| 375 | */ |
| 376 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ |
| 377 | struct list_head node; /* anchored at ss->cfts */ |
| 378 | struct kernfs_ops *kf_ops; |
| 379 | |
| 380 | /* |
| 381 | * read_u64() is a shortcut for the common case of returning a |
| 382 | * single integer. Use it in place of read() |
| 383 | */ |
| 384 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); |
| 385 | /* |
| 386 | * read_s64() is a signed version of read_u64() |
| 387 | */ |
| 388 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); |
| 389 | |
| 390 | /* generic seq_file read interface */ |
| 391 | int (*seq_show)(struct seq_file *sf, void *v); |
| 392 | |
| 393 | /* optional ops, implement all or none */ |
| 394 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); |
| 395 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); |
| 396 | void (*seq_stop)(struct seq_file *sf, void *v); |
| 397 | |
| 398 | /* |
| 399 | * write_u64() is a shortcut for the common case of accepting |
| 400 | * a single integer (as parsed by simple_strtoull) from |
| 401 | * userspace. Use in place of write(); return 0 or error. |
| 402 | */ |
| 403 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, |
| 404 | u64 val); |
| 405 | /* |
| 406 | * write_s64() is a signed version of write_u64() |
| 407 | */ |
| 408 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, |
| 409 | s64 val); |
| 410 | |
| 411 | /* |
| 412 | * write() is the generic write callback which maps directly to |
| 413 | * kernfs write operation and overrides all other operations. |
| 414 | * Maximum write size is determined by ->max_write_len. Use |
| 415 | * of_css/cft() to access the associated css and cft. |
| 416 | */ |
| 417 | ssize_t (*write)(struct kernfs_open_file *of, |
| 418 | char *buf, size_t nbytes, loff_t off); |
| 419 | |
| 420 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 421 | struct lock_class_key lockdep_key; |
| 422 | #endif |
| 423 | }; |
| 424 | |
| 425 | /* |
| 426 | * Control Group subsystem type. |
| 427 | * See Documentation/cgroups/cgroups.txt for details |
| 428 | */ |
| 429 | struct cgroup_subsys { |
| 430 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); |
| 431 | int (*css_online)(struct cgroup_subsys_state *css); |
| 432 | void (*css_offline)(struct cgroup_subsys_state *css); |
| 433 | void (*css_released)(struct cgroup_subsys_state *css); |
| 434 | void (*css_free)(struct cgroup_subsys_state *css); |
| 435 | void (*css_reset)(struct cgroup_subsys_state *css); |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 436 | |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 437 | int (*can_attach)(struct cgroup_taskset *tset); |
| 438 | void (*cancel_attach)(struct cgroup_taskset *tset); |
| 439 | void (*attach)(struct cgroup_taskset *tset); |
Oleg Nesterov | b53202e | 2015-12-03 10:24:08 -0500 | [diff] [blame] | 440 | int (*can_fork)(struct task_struct *task); |
| 441 | void (*cancel_fork)(struct task_struct *task); |
| 442 | void (*fork)(struct task_struct *task); |
Tejun Heo | 2e91fa7 | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 443 | void (*exit)(struct task_struct *task); |
Tejun Heo | afcf6c8 | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 444 | void (*free)(struct task_struct *task); |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 445 | void (*bind)(struct cgroup_subsys_state *root_css); |
| 446 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 447 | int early_init; |
| 448 | |
| 449 | /* |
| 450 | * If %false, this subsystem is properly hierarchical - |
| 451 | * configuration, resource accounting and restriction on a parent |
| 452 | * cgroup cover those of its children. If %true, hierarchy support |
| 453 | * is broken in some ways - some subsystems ignore hierarchy |
| 454 | * completely while others are only implemented half-way. |
| 455 | * |
| 456 | * It's now disallowed to create nested cgroups if the subsystem is |
| 457 | * broken and cgroup core will emit a warning message on such |
| 458 | * cases. Eventually, all subsystems will be made properly |
| 459 | * hierarchical and this will go away. |
| 460 | */ |
| 461 | bool broken_hierarchy; |
| 462 | bool warned_broken_hierarchy; |
| 463 | |
| 464 | /* the following two fields are initialized automtically during boot */ |
| 465 | int id; |
| 466 | const char *name; |
| 467 | |
Tejun Heo | 3e1d2ee | 2015-08-18 13:58:16 -0700 | [diff] [blame] | 468 | /* optional, initialized automatically during boot if not set */ |
| 469 | const char *legacy_name; |
| 470 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 471 | /* link to parent, protected by cgroup_lock() */ |
| 472 | struct cgroup_root *root; |
| 473 | |
| 474 | /* idr for css->id */ |
| 475 | struct idr css_idr; |
| 476 | |
| 477 | /* |
| 478 | * List of cftypes. Each entry is the first entry of an array |
| 479 | * terminated by zero length name. |
| 480 | */ |
| 481 | struct list_head cfts; |
| 482 | |
| 483 | /* |
| 484 | * Base cftypes which are automatically registered. The two can |
| 485 | * point to the same array. |
| 486 | */ |
| 487 | struct cftype *dfl_cftypes; /* for the default hierarchy */ |
| 488 | struct cftype *legacy_cftypes; /* for the legacy hierarchies */ |
| 489 | |
| 490 | /* |
| 491 | * A subsystem may depend on other subsystems. When such subsystem |
| 492 | * is enabled on a cgroup, the depended-upon subsystems are enabled |
| 493 | * together if available. Subsystems enabled due to dependency are |
| 494 | * not visible to userland until explicitly enabled. The following |
| 495 | * specifies the mask of subsystems that this one depends on. |
| 496 | */ |
| 497 | unsigned int depends_on; |
| 498 | }; |
| 499 | |
Tejun Heo | 1ed1328 | 2015-09-16 12:53:17 -0400 | [diff] [blame] | 500 | extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; |
| 501 | |
| 502 | /** |
| 503 | * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups |
| 504 | * @tsk: target task |
| 505 | * |
| 506 | * Called from threadgroup_change_begin() and allows cgroup operations to |
| 507 | * synchronize against threadgroup changes using a percpu_rw_semaphore. |
| 508 | */ |
| 509 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) |
| 510 | { |
| 511 | percpu_down_read(&cgroup_threadgroup_rwsem); |
| 512 | } |
| 513 | |
| 514 | /** |
| 515 | * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups |
| 516 | * @tsk: target task |
| 517 | * |
| 518 | * Called from threadgroup_change_end(). Counterpart of |
| 519 | * cgroup_threadcgroup_change_begin(). |
| 520 | */ |
| 521 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) |
| 522 | { |
| 523 | percpu_up_read(&cgroup_threadgroup_rwsem); |
| 524 | } |
Tejun Heo | 7d7efec | 2015-05-13 16:35:16 -0400 | [diff] [blame] | 525 | |
| 526 | #else /* CONFIG_CGROUPS */ |
| 527 | |
Aleksa Sarai | cb4a316 | 2015-06-06 10:02:14 +1000 | [diff] [blame] | 528 | #define CGROUP_SUBSYS_COUNT 0 |
| 529 | |
Tejun Heo | 7d7efec | 2015-05-13 16:35:16 -0400 | [diff] [blame] | 530 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) {} |
| 531 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} |
| 532 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 533 | #endif /* CONFIG_CGROUPS */ |
Tejun Heo | 7d7efec | 2015-05-13 16:35:16 -0400 | [diff] [blame] | 534 | |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 535 | #ifdef CONFIG_SOCK_CGROUP_DATA |
| 536 | |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 537 | /* |
| 538 | * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains |
| 539 | * per-socket cgroup information except for memcg association. |
| 540 | * |
| 541 | * On legacy hierarchies, net_prio and net_cls controllers directly set |
| 542 | * attributes on each sock which can then be tested by the network layer. |
| 543 | * On the default hierarchy, each sock is associated with the cgroup it was |
| 544 | * created in and the networking layer can match the cgroup directly. |
| 545 | * |
| 546 | * To avoid carrying all three cgroup related fields separately in sock, |
| 547 | * sock_cgroup_data overloads (prioidx, classid) and the cgroup pointer. |
| 548 | * On boot, sock_cgroup_data records the cgroup that the sock was created |
| 549 | * in so that cgroup2 matches can be made; however, once either net_prio or |
| 550 | * net_cls starts being used, the area is overriden to carry prioidx and/or |
| 551 | * classid. The two modes are distinguished by whether the lowest bit is |
| 552 | * set. Clear bit indicates cgroup pointer while set bit prioidx and |
| 553 | * classid. |
| 554 | * |
| 555 | * While userland may start using net_prio or net_cls at any time, once |
| 556 | * either is used, cgroup2 matching no longer works. There is no reason to |
| 557 | * mix the two and this is in line with how legacy and v2 compatibility is |
| 558 | * handled. On mode switch, cgroup references which are already being |
| 559 | * pointed to by socks may be leaked. While this can be remedied by adding |
| 560 | * synchronization around sock_cgroup_data, given that the number of leaked |
| 561 | * cgroups is bound and highly unlikely to be high, this seems to be the |
| 562 | * better trade-off. |
| 563 | */ |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 564 | struct sock_cgroup_data { |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 565 | union { |
| 566 | #ifdef __LITTLE_ENDIAN |
| 567 | struct { |
| 568 | u8 is_data; |
| 569 | u8 padding; |
| 570 | u16 prioidx; |
| 571 | u32 classid; |
| 572 | } __packed; |
| 573 | #else |
| 574 | struct { |
| 575 | u32 classid; |
| 576 | u16 prioidx; |
| 577 | u8 padding; |
| 578 | u8 is_data; |
| 579 | } __packed; |
| 580 | #endif |
| 581 | u64 val; |
| 582 | }; |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 583 | }; |
| 584 | |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 585 | /* |
| 586 | * There's a theoretical window where the following accessors race with |
| 587 | * updaters and return part of the previous pointer as the prioidx or |
| 588 | * classid. Such races are short-lived and the result isn't critical. |
| 589 | */ |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 590 | static inline u16 sock_cgroup_prioidx(struct sock_cgroup_data *skcd) |
| 591 | { |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 592 | /* fallback to 1 which is always the ID of the root cgroup */ |
| 593 | return (skcd->is_data & 1) ? skcd->prioidx : 1; |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 594 | } |
| 595 | |
| 596 | static inline u32 sock_cgroup_classid(struct sock_cgroup_data *skcd) |
| 597 | { |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 598 | /* fallback to 0 which is the unconfigured default classid */ |
| 599 | return (skcd->is_data & 1) ? skcd->classid : 0; |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 600 | } |
| 601 | |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 602 | /* |
| 603 | * If invoked concurrently, the updaters may clobber each other. The |
| 604 | * caller is responsible for synchronization. |
| 605 | */ |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 606 | static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, |
| 607 | u16 prioidx) |
| 608 | { |
Tejun Heo | ad2c8c7 | 2015-12-09 12:30:46 -0500 | [diff] [blame] | 609 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 610 | |
| 611 | if (sock_cgroup_prioidx(&skcd_buf) == prioidx) |
| 612 | return; |
| 613 | |
| 614 | if (!(skcd_buf.is_data & 1)) { |
| 615 | skcd_buf.val = 0; |
| 616 | skcd_buf.is_data = 1; |
| 617 | } |
| 618 | |
| 619 | skcd_buf.prioidx = prioidx; |
| 620 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 621 | } |
| 622 | |
| 623 | static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, |
| 624 | u32 classid) |
| 625 | { |
Tejun Heo | ad2c8c7 | 2015-12-09 12:30:46 -0500 | [diff] [blame] | 626 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 627 | |
| 628 | if (sock_cgroup_classid(&skcd_buf) == classid) |
| 629 | return; |
| 630 | |
| 631 | if (!(skcd_buf.is_data & 1)) { |
| 632 | skcd_buf.val = 0; |
| 633 | skcd_buf.is_data = 1; |
| 634 | } |
| 635 | |
| 636 | skcd_buf.classid = classid; |
| 637 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ |
Tejun Heo | 2a56a1f | 2015-12-07 17:38:52 -0500 | [diff] [blame] | 638 | } |
| 639 | |
| 640 | #else /* CONFIG_SOCK_CGROUP_DATA */ |
| 641 | |
| 642 | struct sock_cgroup_data { |
| 643 | }; |
| 644 | |
| 645 | #endif /* CONFIG_SOCK_CGROUP_DATA */ |
| 646 | |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 647 | #endif /* _LINUX_CGROUP_DEFS_H */ |