1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * linux/cgroup-defs.h - basic definitions for cgroup 4 * 5 * This file provides basic type and interface. Include this file directly 6 * only if necessary to avoid cyclic dependencies. 7 */ 8 #ifndef _LINUX_CGROUP_DEFS_H 9 #define _LINUX_CGROUP_DEFS_H 10 11 #include <linux/limits.h> 12 #include <linux/list.h> 13 #include <linux/idr.h> 14 #include <linux/wait.h> 15 #include <linux/mutex.h> 16 #include <linux/rcupdate.h> 17 #include <linux/refcount.h> 18 #include <linux/percpu-refcount.h> 19 #include <linux/percpu-rwsem.h> 20 #include <linux/u64_stats_sync.h> 21 #include <linux/workqueue.h> 22 #include <linux/bpf-cgroup-defs.h> 23 #include <linux/psi_types.h> 24 25 #ifdef CONFIG_CGROUPS 26 27 struct cgroup; 28 struct cgroup_root; 29 struct cgroup_subsys; 30 struct cgroup_taskset; 31 struct kernfs_node; 32 struct kernfs_ops; 33 struct kernfs_open_file; 34 struct seq_file; 35 struct poll_table_struct; 36 37 #define MAX_CGROUP_TYPE_NAMELEN 32 38 #define MAX_CGROUP_ROOT_NAMELEN 64 39 #define MAX_CFTYPE_NAME 64 40 41 /* define the enumeration of all cgroup subsystems */ 42 #define SUBSYS(_x) _x ## _cgrp_id, 43 enum cgroup_subsys_id { 44 #include <linux/cgroup_subsys.h> 45 CGROUP_SUBSYS_COUNT, 46 }; 47 #undef SUBSYS 48 49 /* bits in struct cgroup_subsys_state flags field */ 50 enum { 51 CSS_NO_REF = (1 << 0), /* no reference counting for this css */ 52 CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ 53 CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ 54 CSS_VISIBLE = (1 << 3), /* css is visible to userland */ 55 CSS_DYING = (1 << 4), /* css is dying */ 56 }; 57 58 /* bits in struct cgroup flags field */ 59 enum { 60 /* Control Group requires release notifications to userspace */ 61 CGRP_NOTIFY_ON_RELEASE, 62 /* 63 * Clone the parent's configuration when creating a new child 64 * cpuset cgroup. For historical reasons, this option can be 65 * specified at mount time and thus is implemented here. 66 */ 67 CGRP_CPUSET_CLONE_CHILDREN, 68 69 /* Control group has to be frozen. */ 70 CGRP_FREEZE, 71 72 /* Cgroup is frozen. */ 73 CGRP_FROZEN, 74 75 /* Control group has to be killed. */ 76 CGRP_KILL, 77 }; 78 79 /* cgroup_root->flags */ 80 enum { 81 CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ 82 CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ 83 84 /* 85 * Consider namespaces as delegation boundaries. If this flag is 86 * set, controller specific interface files in a namespace root 87 * aren't writeable from inside the namespace. 88 */ 89 CGRP_ROOT_NS_DELEGATE = (1 << 3), 90 91 /* 92 * Enable cpuset controller in v1 cgroup to use v2 behavior. 93 */ 94 CGRP_ROOT_CPUSET_V2_MODE = (1 << 4), 95 96 /* 97 * Enable legacy local memory.events. 98 */ 99 CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 5), 100 101 /* 102 * Enable recursive subtree protection 103 */ 104 CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 6), 105 }; 106 107 /* cftype->flags */ 108 enum { 109 CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ 110 CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ 111 CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */ 112 113 CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ 114 CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ 115 CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */ 116 CFTYPE_PRESSURE = (1 << 6), /* only if pressure feature is enabled */ 117 118 /* internal flags, do not use outside cgroup core proper */ 119 __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ 120 __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ 121 }; 122 123 /* 124 * cgroup_file is the handle for a file instance created in a cgroup which 125 * is used, for example, to generate file changed notifications. This can 126 * be obtained by setting cftype->file_offset. 127 */ 128 struct cgroup_file { 129 /* do not access any fields from outside cgroup core */ 130 struct kernfs_node *kn; 131 unsigned long notified_at; 132 struct timer_list notify_timer; 133 }; 134 135 /* 136 * Per-subsystem/per-cgroup state maintained by the system. This is the 137 * fundamental structural building block that controllers deal with. 138 * 139 * Fields marked with "PI:" are public and immutable and may be accessed 140 * directly without synchronization. 141 */ 142 struct cgroup_subsys_state { 143 /* PI: the cgroup that this css is attached to */ 144 struct cgroup *cgroup; 145 146 /* PI: the cgroup subsystem that this css is attached to */ 147 struct cgroup_subsys *ss; 148 149 /* reference count - access via css_[try]get() and css_put() */ 150 struct percpu_ref refcnt; 151 152 /* siblings list anchored at the parent's ->children */ 153 struct list_head sibling; 154 struct list_head children; 155 156 /* flush target list anchored at cgrp->rstat_css_list */ 157 struct list_head rstat_css_node; 158 159 /* 160 * PI: Subsys-unique ID. 0 is unused and root is always 1. The 161 * matching css can be looked up using css_from_id(). 162 */ 163 int id; 164 165 unsigned int flags; 166 167 /* 168 * Monotonically increasing unique serial number which defines a 169 * uniform order among all csses. It's guaranteed that all 170 * ->children lists are in the ascending order of ->serial_nr and 171 * used to allow interrupting and resuming iterations. 172 */ 173 u64 serial_nr; 174 175 /* 176 * Incremented by online self and children. Used to guarantee that 177 * parents are not offlined before their children. 178 */ 179 atomic_t online_cnt; 180 181 /* percpu_ref killing and RCU release */ 182 struct work_struct destroy_work; 183 struct rcu_work destroy_rwork; 184 185 /* 186 * PI: the parent css. Placed here for cache proximity to following 187 * fields of the containing structure. 188 */ 189 struct cgroup_subsys_state *parent; 190 }; 191 192 /* 193 * A css_set is a structure holding pointers to a set of 194 * cgroup_subsys_state objects. This saves space in the task struct 195 * object and speeds up fork()/exit(), since a single inc/dec and a 196 * list_add()/del() can bump the reference count on the entire cgroup 197 * set for a task. 198 */ 199 struct css_set { 200 /* 201 * Set of subsystem states, one for each subsystem. This array is 202 * immutable after creation apart from the init_css_set during 203 * subsystem registration (at boot time). 204 */ 205 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; 206 207 /* reference count */ 208 refcount_t refcount; 209 210 /* 211 * For a domain cgroup, the following points to self. If threaded, 212 * to the matching cset of the nearest domain ancestor. The 213 * dom_cset provides access to the domain cgroup and its csses to 214 * which domain level resource consumptions should be charged. 215 */ 216 struct css_set *dom_cset; 217 218 /* the default cgroup associated with this css_set */ 219 struct cgroup *dfl_cgrp; 220 221 /* internal task count, protected by css_set_lock */ 222 int nr_tasks; 223 224 /* 225 * Lists running through all tasks using this cgroup group. 226 * mg_tasks lists tasks which belong to this cset but are in the 227 * process of being migrated out or in. Protected by 228 * css_set_rwsem, but, during migration, once tasks are moved to 229 * mg_tasks, it can be read safely while holding cgroup_mutex. 230 */ 231 struct list_head tasks; 232 struct list_head mg_tasks; 233 struct list_head dying_tasks; 234 235 /* all css_task_iters currently walking this cset */ 236 struct list_head task_iters; 237 238 /* 239 * On the default hierarchy, ->subsys[ssid] may point to a css 240 * attached to an ancestor instead of the cgroup this css_set is 241 * associated with. The following node is anchored at 242 * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to 243 * iterate through all css's attached to a given cgroup. 244 */ 245 struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; 246 247 /* all threaded csets whose ->dom_cset points to this cset */ 248 struct list_head threaded_csets; 249 struct list_head threaded_csets_node; 250 251 /* 252 * List running through all cgroup groups in the same hash 253 * slot. Protected by css_set_lock 254 */ 255 struct hlist_node hlist; 256 257 /* 258 * List of cgrp_cset_links pointing at cgroups referenced from this 259 * css_set. Protected by css_set_lock. 260 */ 261 struct list_head cgrp_links; 262 263 /* 264 * List of csets participating in the on-going migration either as 265 * source or destination. Protected by cgroup_mutex. 266 */ 267 struct list_head mg_src_preload_node; 268 struct list_head mg_dst_preload_node; 269 struct list_head mg_node; 270 271 /* 272 * If this cset is acting as the source of migration the following 273 * two fields are set. mg_src_cgrp and mg_dst_cgrp are 274 * respectively the source and destination cgroups of the on-going 275 * migration. mg_dst_cset is the destination cset the target tasks 276 * on this cset should be migrated to. Protected by cgroup_mutex. 277 */ 278 struct cgroup *mg_src_cgrp; 279 struct cgroup *mg_dst_cgrp; 280 struct css_set *mg_dst_cset; 281 282 /* dead and being drained, ignore for migration */ 283 bool dead; 284 285 /* For RCU-protected deletion */ 286 struct rcu_head rcu_head; 287 }; 288 289 struct cgroup_base_stat { 290 struct task_cputime cputime; 291 }; 292 293 /* 294 * rstat - cgroup scalable recursive statistics. Accounting is done 295 * per-cpu in cgroup_rstat_cpu which is then lazily propagated up the 296 * hierarchy on reads. 297 * 298 * When a stat gets updated, the cgroup_rstat_cpu and its ancestors are 299 * linked into the updated tree. On the following read, propagation only 300 * considers and consumes the updated tree. This makes reading O(the 301 * number of descendants which have been active since last read) instead of 302 * O(the total number of descendants). 303 * 304 * This is important because there can be a lot of (draining) cgroups which 305 * aren't active and stat may be read frequently. The combination can 306 * become very expensive. By propagating selectively, increasing reading 307 * frequency decreases the cost of each read. 308 * 309 * This struct hosts both the fields which implement the above - 310 * updated_children and updated_next - and the fields which track basic 311 * resource statistics on top of it - bsync, bstat and last_bstat. 312 */ 313 struct cgroup_rstat_cpu { 314 /* 315 * ->bsync protects ->bstat. These are the only fields which get 316 * updated in the hot path. 317 */ 318 struct u64_stats_sync bsync; 319 struct cgroup_base_stat bstat; 320 321 /* 322 * Snapshots at the last reading. These are used to calculate the 323 * deltas to propagate to the global counters. 324 */ 325 struct cgroup_base_stat last_bstat; 326 327 /* 328 * Child cgroups with stat updates on this cpu since the last read 329 * are linked on the parent's ->updated_children through 330 * ->updated_next. 331 * 332 * In addition to being more compact, singly-linked list pointing 333 * to the cgroup makes it unnecessary for each per-cpu struct to 334 * point back to the associated cgroup. 335 * 336 * Protected by per-cpu cgroup_rstat_cpu_lock. 337 */ 338 struct cgroup *updated_children; /* terminated by self cgroup */ 339 struct cgroup *updated_next; /* NULL iff not on the list */ 340 }; 341 342 struct cgroup_freezer_state { 343 /* Should the cgroup and its descendants be frozen. */ 344 bool freeze; 345 346 /* Should the cgroup actually be frozen? */ 347 int e_freeze; 348 349 /* Fields below are protected by css_set_lock */ 350 351 /* Number of frozen descendant cgroups */ 352 int nr_frozen_descendants; 353 354 /* 355 * Number of tasks, which are counted as frozen: 356 * frozen, SIGSTOPped, and PTRACEd. 357 */ 358 int nr_frozen_tasks; 359 }; 360 361 struct cgroup { 362 /* self css with NULL ->ss, points back to this cgroup */ 363 struct cgroup_subsys_state self; 364 365 unsigned long flags; /* "unsigned long" so bitops work */ 366 367 /* 368 * The depth this cgroup is at. The root is at depth zero and each 369 * step down the hierarchy increments the level. This along with 370 * ancestor_ids[] can determine whether a given cgroup is a 371 * descendant of another without traversing the hierarchy. 372 */ 373 int level; 374 375 /* Maximum allowed descent tree depth */ 376 int max_depth; 377 378 /* 379 * Keep track of total numbers of visible and dying descent cgroups. 380 * Dying cgroups are cgroups which were deleted by a user, 381 * but are still existing because someone else is holding a reference. 382 * max_descendants is a maximum allowed number of descent cgroups. 383 * 384 * nr_descendants and nr_dying_descendants are protected 385 * by cgroup_mutex and css_set_lock. It's fine to read them holding 386 * any of cgroup_mutex and css_set_lock; for writing both locks 387 * should be held. 388 */ 389 int nr_descendants; 390 int nr_dying_descendants; 391 int max_descendants; 392 393 /* 394 * Each non-empty css_set associated with this cgroup contributes 395 * one to nr_populated_csets. The counter is zero iff this cgroup 396 * doesn't have any tasks. 397 * 398 * All children which have non-zero nr_populated_csets and/or 399 * nr_populated_children of their own contribute one to either 400 * nr_populated_domain_children or nr_populated_threaded_children 401 * depending on their type. Each counter is zero iff all cgroups 402 * of the type in the subtree proper don't have any tasks. 403 */ 404 int nr_populated_csets; 405 int nr_populated_domain_children; 406 int nr_populated_threaded_children; 407 408 int nr_threaded_children; /* # of live threaded child cgroups */ 409 410 struct kernfs_node *kn; /* cgroup kernfs entry */ 411 struct cgroup_file procs_file; /* handle for "cgroup.procs" */ 412 struct cgroup_file events_file; /* handle for "cgroup.events" */ 413 414 /* 415 * The bitmask of subsystems enabled on the child cgroups. 416 * ->subtree_control is the one configured through 417 * "cgroup.subtree_control" while ->subtree_ss_mask is the effective 418 * one which may have more subsystems enabled. Controller knobs 419 * are made available iff it's enabled in ->subtree_control. 420 */ 421 u16 subtree_control; 422 u16 subtree_ss_mask; 423 u16 old_subtree_control; 424 u16 old_subtree_ss_mask; 425 426 /* Private pointers for each registered subsystem */ 427 struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; 428 429 struct cgroup_root *root; 430 431 /* 432 * List of cgrp_cset_links pointing at css_sets with tasks in this 433 * cgroup. Protected by css_set_lock. 434 */ 435 struct list_head cset_links; 436 437 /* 438 * On the default hierarchy, a css_set for a cgroup with some 439 * susbsys disabled will point to css's which are associated with 440 * the closest ancestor which has the subsys enabled. The 441 * following lists all css_sets which point to this cgroup's css 442 * for the given subsystem. 443 */ 444 struct list_head e_csets[CGROUP_SUBSYS_COUNT]; 445 446 /* 447 * If !threaded, self. If threaded, it points to the nearest 448 * domain ancestor. Inside a threaded subtree, cgroups are exempt 449 * from process granularity and no-internal-task constraint. 450 * Domain level resource consumptions which aren't tied to a 451 * specific task are charged to the dom_cgrp. 452 */ 453 struct cgroup *dom_cgrp; 454 struct cgroup *old_dom_cgrp; /* used while enabling threaded */ 455 456 /* per-cpu recursive resource statistics */ 457 struct cgroup_rstat_cpu __percpu *rstat_cpu; 458 struct list_head rstat_css_list; 459 460 /* cgroup basic resource statistics */ 461 struct cgroup_base_stat last_bstat; 462 struct cgroup_base_stat bstat; 463 struct prev_cputime prev_cputime; /* for printing out cputime */ 464 465 /* 466 * list of pidlists, up to two for each namespace (one for procs, one 467 * for tasks); created on demand. 468 */ 469 struct list_head pidlists; 470 struct mutex pidlist_mutex; 471 472 /* used to wait for offlining of csses */ 473 wait_queue_head_t offline_waitq; 474 475 /* used to schedule release agent */ 476 struct work_struct release_agent_work; 477 478 /* used to track pressure stalls */ 479 struct psi_group psi; 480 481 /* used to store eBPF programs */ 482 struct cgroup_bpf bpf; 483 484 /* If there is block congestion on this cgroup. */ 485 atomic_t congestion_count; 486 487 /* Used to store internal freezer state */ 488 struct cgroup_freezer_state freezer; 489 490 /* ids of the ancestors at each level including self */ 491 u64 ancestor_ids[]; 492 }; 493 494 /* 495 * A cgroup_root represents the root of a cgroup hierarchy, and may be 496 * associated with a kernfs_root to form an active hierarchy. This is 497 * internal to cgroup core. Don't access directly from controllers. 498 */ 499 struct cgroup_root { 500 struct kernfs_root *kf_root; 501 502 /* The bitmask of subsystems attached to this hierarchy */ 503 unsigned int subsys_mask; 504 505 /* Unique id for this hierarchy. */ 506 int hierarchy_id; 507 508 /* The root cgroup. Root is destroyed on its release. */ 509 struct cgroup cgrp; 510 511 /* for cgrp->ancestor_ids[0] */ 512 u64 cgrp_ancestor_id_storage; 513 514 /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ 515 atomic_t nr_cgrps; 516 517 /* A list running through the active hierarchies */ 518 struct list_head root_list; 519 520 /* Hierarchy-specific flags */ 521 unsigned int flags; 522 523 /* The path to use for release notifications. */ 524 char release_agent_path[PATH_MAX]; 525 526 /* The name for this hierarchy - may be empty */ 527 char name[MAX_CGROUP_ROOT_NAMELEN]; 528 }; 529 530 /* 531 * struct cftype: handler definitions for cgroup control files 532 * 533 * When reading/writing to a file: 534 * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata 535 * - the 'cftype' of the file is file->f_path.dentry->d_fsdata 536 */ 537 struct cftype { 538 /* 539 * By convention, the name should begin with the name of the 540 * subsystem, followed by a period. Zero length string indicates 541 * end of cftype array. 542 */ 543 char name[MAX_CFTYPE_NAME]; 544 unsigned long private; 545 546 /* 547 * The maximum length of string, excluding trailing nul, that can 548 * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. 549 */ 550 size_t max_write_len; 551 552 /* CFTYPE_* flags */ 553 unsigned int flags; 554 555 /* 556 * If non-zero, should contain the offset from the start of css to 557 * a struct cgroup_file field. cgroup will record the handle of 558 * the created file into it. The recorded handle can be used as 559 * long as the containing css remains accessible. 560 */ 561 unsigned int file_offset; 562 563 /* 564 * Fields used for internal bookkeeping. Initialized automatically 565 * during registration. 566 */ 567 struct cgroup_subsys *ss; /* NULL for cgroup core files */ 568 struct list_head node; /* anchored at ss->cfts */ 569 struct kernfs_ops *kf_ops; 570 571 int (*open)(struct kernfs_open_file *of); 572 void (*release)(struct kernfs_open_file *of); 573 574 /* 575 * read_u64() is a shortcut for the common case of returning a 576 * single integer. Use it in place of read() 577 */ 578 u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); 579 /* 580 * read_s64() is a signed version of read_u64() 581 */ 582 s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); 583 584 /* generic seq_file read interface */ 585 int (*seq_show)(struct seq_file *sf, void *v); 586 587 /* optional ops, implement all or none */ 588 void *(*seq_start)(struct seq_file *sf, loff_t *ppos); 589 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); 590 void (*seq_stop)(struct seq_file *sf, void *v); 591 592 /* 593 * write_u64() is a shortcut for the common case of accepting 594 * a single integer (as parsed by simple_strtoull) from 595 * userspace. Use in place of write(); return 0 or error. 596 */ 597 int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, 598 u64 val); 599 /* 600 * write_s64() is a signed version of write_u64() 601 */ 602 int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, 603 s64 val); 604 605 /* 606 * write() is the generic write callback which maps directly to 607 * kernfs write operation and overrides all other operations. 608 * Maximum write size is determined by ->max_write_len. Use 609 * of_css/cft() to access the associated css and cft. 610 */ 611 ssize_t (*write)(struct kernfs_open_file *of, 612 char *buf, size_t nbytes, loff_t off); 613 614 __poll_t (*poll)(struct kernfs_open_file *of, 615 struct poll_table_struct *pt); 616 617 #ifdef CONFIG_DEBUG_LOCK_ALLOC 618 struct lock_class_key lockdep_key; 619 #endif 620 }; 621 622 /* 623 * Control Group subsystem type. 624 * See Documentation/admin-guide/cgroup-v1/cgroups.rst for details 625 */ 626 struct cgroup_subsys { 627 struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); 628 int (*css_online)(struct cgroup_subsys_state *css); 629 void (*css_offline)(struct cgroup_subsys_state *css); 630 void (*css_released)(struct cgroup_subsys_state *css); 631 void (*css_free)(struct cgroup_subsys_state *css); 632 void (*css_reset)(struct cgroup_subsys_state *css); 633 void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu); 634 int (*css_extra_stat_show)(struct seq_file *seq, 635 struct cgroup_subsys_state *css); 636 637 int (*can_attach)(struct cgroup_taskset *tset); 638 void (*cancel_attach)(struct cgroup_taskset *tset); 639 void (*attach)(struct cgroup_taskset *tset); 640 void (*post_attach)(void); 641 int (*can_fork)(struct task_struct *task, 642 struct css_set *cset); 643 void (*cancel_fork)(struct task_struct *task, struct css_set *cset); 644 void (*fork)(struct task_struct *task); 645 void (*exit)(struct task_struct *task); 646 void (*release)(struct task_struct *task); 647 void (*bind)(struct cgroup_subsys_state *root_css); 648 649 bool early_init:1; 650 651 /* 652 * If %true, the controller, on the default hierarchy, doesn't show 653 * up in "cgroup.controllers" or "cgroup.subtree_control", is 654 * implicitly enabled on all cgroups on the default hierarchy, and 655 * bypasses the "no internal process" constraint. This is for 656 * utility type controllers which is transparent to userland. 657 * 658 * An implicit controller can be stolen from the default hierarchy 659 * anytime and thus must be okay with offline csses from previous 660 * hierarchies coexisting with csses for the current one. 661 */ 662 bool implicit_on_dfl:1; 663 664 /* 665 * If %true, the controller, supports threaded mode on the default 666 * hierarchy. In a threaded subtree, both process granularity and 667 * no-internal-process constraint are ignored and a threaded 668 * controllers should be able to handle that. 669 * 670 * Note that as an implicit controller is automatically enabled on 671 * all cgroups on the default hierarchy, it should also be 672 * threaded. implicit && !threaded is not supported. 673 */ 674 bool threaded:1; 675 676 /* the following two fields are initialized automatically during boot */ 677 int id; 678 const char *name; 679 680 /* optional, initialized automatically during boot if not set */ 681 const char *legacy_name; 682 683 /* link to parent, protected by cgroup_lock() */ 684 struct cgroup_root *root; 685 686 /* idr for css->id */ 687 struct idr css_idr; 688 689 /* 690 * List of cftypes. Each entry is the first entry of an array 691 * terminated by zero length name. 692 */ 693 struct list_head cfts; 694 695 /* 696 * Base cftypes which are automatically registered. The two can 697 * point to the same array. 698 */ 699 struct cftype *dfl_cftypes; /* for the default hierarchy */ 700 struct cftype *legacy_cftypes; /* for the legacy hierarchies */ 701 702 /* 703 * A subsystem may depend on other subsystems. When such subsystem 704 * is enabled on a cgroup, the depended-upon subsystems are enabled 705 * together if available. Subsystems enabled due to dependency are 706 * not visible to userland until explicitly enabled. The following 707 * specifies the mask of subsystems that this one depends on. 708 */ 709 unsigned int depends_on; 710 }; 711 712 extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; 713 714 /** 715 * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups 716 * @tsk: target task 717 * 718 * Allows cgroup operations to synchronize against threadgroup changes 719 * using a percpu_rw_semaphore. 720 */ 721 static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) 722 { 723 percpu_down_read(&cgroup_threadgroup_rwsem); 724 } 725 726 /** 727 * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups 728 * @tsk: target task 729 * 730 * Counterpart of cgroup_threadcgroup_change_begin(). 731 */ 732 static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) 733 { 734 percpu_up_read(&cgroup_threadgroup_rwsem); 735 } 736 737 #else /* CONFIG_CGROUPS */ 738 739 #define CGROUP_SUBSYS_COUNT 0 740 741 static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) 742 { 743 might_sleep(); 744 } 745 746 static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} 747 748 #endif /* CONFIG_CGROUPS */ 749 750 #ifdef CONFIG_SOCK_CGROUP_DATA 751 752 /* 753 * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains 754 * per-socket cgroup information except for memcg association. 755 * 756 * On legacy hierarchies, net_prio and net_cls controllers directly 757 * set attributes on each sock which can then be tested by the network 758 * layer. On the default hierarchy, each sock is associated with the 759 * cgroup it was created in and the networking layer can match the 760 * cgroup directly. 761 */ 762 struct sock_cgroup_data { 763 struct cgroup *cgroup; /* v2 */ 764 #ifdef CONFIG_CGROUP_NET_CLASSID 765 u32 classid; /* v1 */ 766 #endif 767 #ifdef CONFIG_CGROUP_NET_PRIO 768 u16 prioidx; /* v1 */ 769 #endif 770 }; 771 772 static inline u16 sock_cgroup_prioidx(const struct sock_cgroup_data *skcd) 773 { 774 #ifdef CONFIG_CGROUP_NET_PRIO 775 return READ_ONCE(skcd->prioidx); 776 #else 777 return 1; 778 #endif 779 } 780 781 static inline u32 sock_cgroup_classid(const struct sock_cgroup_data *skcd) 782 { 783 #ifdef CONFIG_CGROUP_NET_CLASSID 784 return READ_ONCE(skcd->classid); 785 #else 786 return 0; 787 #endif 788 } 789 790 static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, 791 u16 prioidx) 792 { 793 #ifdef CONFIG_CGROUP_NET_PRIO 794 WRITE_ONCE(skcd->prioidx, prioidx); 795 #endif 796 } 797 798 static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, 799 u32 classid) 800 { 801 #ifdef CONFIG_CGROUP_NET_CLASSID 802 WRITE_ONCE(skcd->classid, classid); 803 #endif 804 } 805 806 #else /* CONFIG_SOCK_CGROUP_DATA */ 807 808 struct sock_cgroup_data { 809 }; 810 811 #endif /* CONFIG_SOCK_CGROUP_DATA */ 812 813 #endif /* _LINUX_CGROUP_DEFS_H */ 814