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 27struct cgroup; 28struct cgroup_root; 29struct cgroup_subsys; 30struct cgroup_taskset; 31struct kernfs_node; 32struct kernfs_ops; 33struct kernfs_open_file; 34struct seq_file; 35struct 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, 43enum 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 */ 50enum { 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 */ 59enum { 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 */ 80enum { 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 * Reduce latencies on dynamic cgroup modifications such as task 93 * migrations and controller on/offs by disabling percpu operation on 94 * cgroup_threadgroup_rwsem. This makes hot path operations such as 95 * forks and exits into the slow path and more expensive. 96 * 97 * The static usage pattern of creating a cgroup, enabling controllers, 98 * and then seeding it with CLONE_INTO_CGROUP doesn't require write 99 * locking cgroup_threadgroup_rwsem and thus doesn't benefit from 100 * favordynmod. 101 */ 102 CGRP_ROOT_FAVOR_DYNMODS = (1 << 4), 103 104 /* 105 * Enable cpuset controller in v1 cgroup to use v2 behavior. 106 */ 107 CGRP_ROOT_CPUSET_V2_MODE = (1 << 16), 108 109 /* 110 * Enable legacy local memory.events. 111 */ 112 CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 17), 113 114 /* 115 * Enable recursive subtree protection 116 */ 117 CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18), 118 119 /* 120 * Enable hugetlb accounting for the memory controller. 121 */ 122 CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING = (1 << 19), 123}; 124 125/* cftype->flags */ 126enum { 127 CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ 128 CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ 129 CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */ 130 131 CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ 132 CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ 133 CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */ 134 135 /* internal flags, do not use outside cgroup core proper */ 136 __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ 137 __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ 138 __CFTYPE_ADDED = (1 << 18), 139}; 140 141/* 142 * cgroup_file is the handle for a file instance created in a cgroup which 143 * is used, for example, to generate file changed notifications. This can 144 * be obtained by setting cftype->file_offset. 145 */ 146struct cgroup_file { 147 /* do not access any fields from outside cgroup core */ 148 struct kernfs_node *kn; 149 unsigned long notified_at; 150 struct timer_list notify_timer; 151}; 152 153/* 154 * Per-subsystem/per-cgroup state maintained by the system. This is the 155 * fundamental structural building block that controllers deal with. 156 * 157 * Fields marked with "PI:" are public and immutable and may be accessed 158 * directly without synchronization. 159 */ 160struct cgroup_subsys_state { 161 /* PI: the cgroup that this css is attached to */ 162 struct cgroup *cgroup; 163 164 /* PI: the cgroup subsystem that this css is attached to */ 165 struct cgroup_subsys *ss; 166 167 /* reference count - access via css_[try]get() and css_put() */ 168 struct percpu_ref refcnt; 169 170 /* siblings list anchored at the parent's ->children */ 171 struct list_head sibling; 172 struct list_head children; 173 174 /* flush target list anchored at cgrp->rstat_css_list */ 175 struct list_head rstat_css_node; 176 177 /* 178 * PI: Subsys-unique ID. 0 is unused and root is always 1. The 179 * matching css can be looked up using css_from_id(). 180 */ 181 int id; 182 183 unsigned int flags; 184 185 /* 186 * Monotonically increasing unique serial number which defines a 187 * uniform order among all csses. It's guaranteed that all 188 * ->children lists are in the ascending order of ->serial_nr and 189 * used to allow interrupting and resuming iterations. 190 */ 191 u64 serial_nr; 192 193 /* 194 * Incremented by online self and children. Used to guarantee that 195 * parents are not offlined before their children. 196 */ 197 atomic_t online_cnt; 198 199 /* percpu_ref killing and RCU release */ 200 struct work_struct destroy_work; 201 struct rcu_work destroy_rwork; 202 203 /* 204 * PI: the parent css. Placed here for cache proximity to following 205 * fields of the containing structure. 206 */ 207 struct cgroup_subsys_state *parent; 208}; 209 210/* 211 * A css_set is a structure holding pointers to a set of 212 * cgroup_subsys_state objects. This saves space in the task struct 213 * object and speeds up fork()/exit(), since a single inc/dec and a 214 * list_add()/del() can bump the reference count on the entire cgroup 215 * set for a task. 216 */ 217struct css_set { 218 /* 219 * Set of subsystem states, one for each subsystem. This array is 220 * immutable after creation apart from the init_css_set during 221 * subsystem registration (at boot time). 222 */ 223 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; 224 225 /* reference count */ 226 refcount_t refcount; 227 228 /* 229 * For a domain cgroup, the following points to self. If threaded, 230 * to the matching cset of the nearest domain ancestor. The 231 * dom_cset provides access to the domain cgroup and its csses to 232 * which domain level resource consumptions should be charged. 233 */ 234 struct css_set *dom_cset; 235 236 /* the default cgroup associated with this css_set */ 237 struct cgroup *dfl_cgrp; 238 239 /* internal task count, protected by css_set_lock */ 240 int nr_tasks; 241 242 /* 243 * Lists running through all tasks using this cgroup group. 244 * mg_tasks lists tasks which belong to this cset but are in the 245 * process of being migrated out or in. Protected by 246 * css_set_lock, but, during migration, once tasks are moved to 247 * mg_tasks, it can be read safely while holding cgroup_mutex. 248 */ 249 struct list_head tasks; 250 struct list_head mg_tasks; 251 struct list_head dying_tasks; 252 253 /* all css_task_iters currently walking this cset */ 254 struct list_head task_iters; 255 256 /* 257 * On the default hierarchy, ->subsys[ssid] may point to a css 258 * attached to an ancestor instead of the cgroup this css_set is 259 * associated with. The following node is anchored at 260 * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to 261 * iterate through all css's attached to a given cgroup. 262 */ 263 struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; 264 265 /* all threaded csets whose ->dom_cset points to this cset */ 266 struct list_head threaded_csets; 267 struct list_head threaded_csets_node; 268 269 /* 270 * List running through all cgroup groups in the same hash 271 * slot. Protected by css_set_lock 272 */ 273 struct hlist_node hlist; 274 275 /* 276 * List of cgrp_cset_links pointing at cgroups referenced from this 277 * css_set. Protected by css_set_lock. 278 */ 279 struct list_head cgrp_links; 280 281 /* 282 * List of csets participating in the on-going migration either as 283 * source or destination. Protected by cgroup_mutex. 284 */ 285 struct list_head mg_src_preload_node; 286 struct list_head mg_dst_preload_node; 287 struct list_head mg_node; 288 289 /* 290 * If this cset is acting as the source of migration the following 291 * two fields are set. mg_src_cgrp and mg_dst_cgrp are 292 * respectively the source and destination cgroups of the on-going 293 * migration. mg_dst_cset is the destination cset the target tasks 294 * on this cset should be migrated to. Protected by cgroup_mutex. 295 */ 296 struct cgroup *mg_src_cgrp; 297 struct cgroup *mg_dst_cgrp; 298 struct css_set *mg_dst_cset; 299 300 /* dead and being drained, ignore for migration */ 301 bool dead; 302 303 /* For RCU-protected deletion */ 304 struct rcu_head rcu_head; 305}; 306 307struct cgroup_base_stat { 308 struct task_cputime cputime; 309 310#ifdef CONFIG_SCHED_CORE 311 u64 forceidle_sum; 312#endif 313}; 314 315/* 316 * rstat - cgroup scalable recursive statistics. Accounting is done 317 * per-cpu in cgroup_rstat_cpu which is then lazily propagated up the 318 * hierarchy on reads. 319 * 320 * When a stat gets updated, the cgroup_rstat_cpu and its ancestors are 321 * linked into the updated tree. On the following read, propagation only 322 * considers and consumes the updated tree. This makes reading O(the 323 * number of descendants which have been active since last read) instead of 324 * O(the total number of descendants). 325 * 326 * This is important because there can be a lot of (draining) cgroups which 327 * aren't active and stat may be read frequently. The combination can 328 * become very expensive. By propagating selectively, increasing reading 329 * frequency decreases the cost of each read. 330 * 331 * This struct hosts both the fields which implement the above - 332 * updated_children and updated_next - and the fields which track basic 333 * resource statistics on top of it - bsync, bstat and last_bstat. 334 */ 335struct cgroup_rstat_cpu { 336 /* 337 * ->bsync protects ->bstat. These are the only fields which get 338 * updated in the hot path. 339 */ 340 struct u64_stats_sync bsync; 341 struct cgroup_base_stat bstat; 342 343 /* 344 * Snapshots at the last reading. These are used to calculate the 345 * deltas to propagate to the global counters. 346 */ 347 struct cgroup_base_stat last_bstat; 348 349 /* 350 * This field is used to record the cumulative per-cpu time of 351 * the cgroup and its descendants. Currently it can be read via 352 * eBPF/drgn etc, and we are still trying to determine how to 353 * expose it in the cgroupfs interface. 354 */ 355 struct cgroup_base_stat subtree_bstat; 356 357 /* 358 * Snapshots at the last reading. These are used to calculate the 359 * deltas to propagate to the per-cpu subtree_bstat. 360 */ 361 struct cgroup_base_stat last_subtree_bstat; 362 363 /* 364 * Child cgroups with stat updates on this cpu since the last read 365 * are linked on the parent's ->updated_children through 366 * ->updated_next. 367 * 368 * In addition to being more compact, singly-linked list pointing 369 * to the cgroup makes it unnecessary for each per-cpu struct to 370 * point back to the associated cgroup. 371 * 372 * Protected by per-cpu cgroup_rstat_cpu_lock. 373 */ 374 struct cgroup *updated_children; /* terminated by self cgroup */ 375 struct cgroup *updated_next; /* NULL iff not on the list */ 376}; 377 378struct cgroup_freezer_state { 379 /* Should the cgroup and its descendants be frozen. */ 380 bool freeze; 381 382 /* Should the cgroup actually be frozen? */ 383 int e_freeze; 384 385 /* Fields below are protected by css_set_lock */ 386 387 /* Number of frozen descendant cgroups */ 388 int nr_frozen_descendants; 389 390 /* 391 * Number of tasks, which are counted as frozen: 392 * frozen, SIGSTOPped, and PTRACEd. 393 */ 394 int nr_frozen_tasks; 395}; 396 397struct cgroup { 398 /* self css with NULL ->ss, points back to this cgroup */ 399 struct cgroup_subsys_state self; 400 401 unsigned long flags; /* "unsigned long" so bitops work */ 402 403 /* 404 * The depth this cgroup is at. The root is at depth zero and each 405 * step down the hierarchy increments the level. This along with 406 * ancestors[] can determine whether a given cgroup is a 407 * descendant of another without traversing the hierarchy. 408 */ 409 int level; 410 411 /* Maximum allowed descent tree depth */ 412 int max_depth; 413 414 /* 415 * Keep track of total numbers of visible and dying descent cgroups. 416 * Dying cgroups are cgroups which were deleted by a user, 417 * but are still existing because someone else is holding a reference. 418 * max_descendants is a maximum allowed number of descent cgroups. 419 * 420 * nr_descendants and nr_dying_descendants are protected 421 * by cgroup_mutex and css_set_lock. It's fine to read them holding 422 * any of cgroup_mutex and css_set_lock; for writing both locks 423 * should be held. 424 */ 425 int nr_descendants; 426 int nr_dying_descendants; 427 int max_descendants; 428 429 /* 430 * Each non-empty css_set associated with this cgroup contributes 431 * one to nr_populated_csets. The counter is zero iff this cgroup 432 * doesn't have any tasks. 433 * 434 * All children which have non-zero nr_populated_csets and/or 435 * nr_populated_children of their own contribute one to either 436 * nr_populated_domain_children or nr_populated_threaded_children 437 * depending on their type. Each counter is zero iff all cgroups 438 * of the type in the subtree proper don't have any tasks. 439 */ 440 int nr_populated_csets; 441 int nr_populated_domain_children; 442 int nr_populated_threaded_children; 443 444 int nr_threaded_children; /* # of live threaded child cgroups */ 445 446 struct kernfs_node *kn; /* cgroup kernfs entry */ 447 struct cgroup_file procs_file; /* handle for "cgroup.procs" */ 448 struct cgroup_file events_file; /* handle for "cgroup.events" */ 449 450 /* handles for "{cpu,memory,io,irq}.pressure" */ 451 struct cgroup_file psi_files[NR_PSI_RESOURCES]; 452 453 /* 454 * The bitmask of subsystems enabled on the child cgroups. 455 * ->subtree_control is the one configured through 456 * "cgroup.subtree_control" while ->subtree_ss_mask is the effective 457 * one which may have more subsystems enabled. Controller knobs 458 * are made available iff it's enabled in ->subtree_control. 459 */ 460 u16 subtree_control; 461 u16 subtree_ss_mask; 462 u16 old_subtree_control; 463 u16 old_subtree_ss_mask; 464 465 /* Private pointers for each registered subsystem */ 466 struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; 467 468 struct cgroup_root *root; 469 470 /* 471 * List of cgrp_cset_links pointing at css_sets with tasks in this 472 * cgroup. Protected by css_set_lock. 473 */ 474 struct list_head cset_links; 475 476 /* 477 * On the default hierarchy, a css_set for a cgroup with some 478 * susbsys disabled will point to css's which are associated with 479 * the closest ancestor which has the subsys enabled. The 480 * following lists all css_sets which point to this cgroup's css 481 * for the given subsystem. 482 */ 483 struct list_head e_csets[CGROUP_SUBSYS_COUNT]; 484 485 /* 486 * If !threaded, self. If threaded, it points to the nearest 487 * domain ancestor. Inside a threaded subtree, cgroups are exempt 488 * from process granularity and no-internal-task constraint. 489 * Domain level resource consumptions which aren't tied to a 490 * specific task are charged to the dom_cgrp. 491 */ 492 struct cgroup *dom_cgrp; 493 struct cgroup *old_dom_cgrp; /* used while enabling threaded */ 494 495 /* per-cpu recursive resource statistics */ 496 struct cgroup_rstat_cpu __percpu *rstat_cpu; 497 struct list_head rstat_css_list; 498 499 /* 500 * Add padding to separate the read mostly rstat_cpu and 501 * rstat_css_list into a different cacheline from the following 502 * rstat_flush_next and *bstat fields which can have frequent updates. 503 */ 504 CACHELINE_PADDING(_pad_); 505 506 /* 507 * A singly-linked list of cgroup structures to be rstat flushed. 508 * This is a scratch field to be used exclusively by 509 * cgroup_rstat_flush_locked() and protected by cgroup_rstat_lock. 510 */ 511 struct cgroup *rstat_flush_next; 512 513 /* cgroup basic resource statistics */ 514 struct cgroup_base_stat last_bstat; 515 struct cgroup_base_stat bstat; 516 struct prev_cputime prev_cputime; /* for printing out cputime */ 517 518 /* 519 * list of pidlists, up to two for each namespace (one for procs, one 520 * for tasks); created on demand. 521 */ 522 struct list_head pidlists; 523 struct mutex pidlist_mutex; 524 525 /* used to wait for offlining of csses */ 526 wait_queue_head_t offline_waitq; 527 528 /* used to schedule release agent */ 529 struct work_struct release_agent_work; 530 531 /* used to track pressure stalls */ 532 struct psi_group *psi; 533 534 /* used to store eBPF programs */ 535 struct cgroup_bpf bpf; 536 537 /* If there is block congestion on this cgroup. */ 538 atomic_t congestion_count; 539 540 /* Used to store internal freezer state */ 541 struct cgroup_freezer_state freezer; 542 543#ifdef CONFIG_BPF_SYSCALL 544 struct bpf_local_storage __rcu *bpf_cgrp_storage; 545#endif 546 547 /* All ancestors including self */ 548 struct cgroup *ancestors[]; 549}; 550 551/* 552 * A cgroup_root represents the root of a cgroup hierarchy, and may be 553 * associated with a kernfs_root to form an active hierarchy. This is 554 * internal to cgroup core. Don't access directly from controllers. 555 */ 556struct cgroup_root { 557 struct kernfs_root *kf_root; 558 559 /* The bitmask of subsystems attached to this hierarchy */ 560 unsigned int subsys_mask; 561 562 /* Unique id for this hierarchy. */ 563 int hierarchy_id; 564 565 /* A list running through the active hierarchies */ 566 struct list_head root_list; 567 struct rcu_head rcu; /* Must be near the top */ 568 569 /* 570 * The root cgroup. The containing cgroup_root will be destroyed on its 571 * release. cgrp->ancestors[0] will be used overflowing into the 572 * following field. cgrp_ancestor_storage must immediately follow. 573 */ 574 struct cgroup cgrp; 575 576 /* must follow cgrp for cgrp->ancestors[0], see above */ 577 struct cgroup *cgrp_ancestor_storage; 578 579 /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ 580 atomic_t nr_cgrps; 581 582 /* Hierarchy-specific flags */ 583 unsigned int flags; 584 585 /* The path to use for release notifications. */ 586 char release_agent_path[PATH_MAX]; 587 588 /* The name for this hierarchy - may be empty */ 589 char name[MAX_CGROUP_ROOT_NAMELEN]; 590}; 591 592/* 593 * struct cftype: handler definitions for cgroup control files 594 * 595 * When reading/writing to a file: 596 * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata 597 * - the 'cftype' of the file is file->f_path.dentry->d_fsdata 598 */ 599struct cftype { 600 /* 601 * By convention, the name should begin with the name of the 602 * subsystem, followed by a period. Zero length string indicates 603 * end of cftype array. 604 */ 605 char name[MAX_CFTYPE_NAME]; 606 unsigned long private; 607 608 /* 609 * The maximum length of string, excluding trailing nul, that can 610 * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. 611 */ 612 size_t max_write_len; 613 614 /* CFTYPE_* flags */ 615 unsigned int flags; 616 617 /* 618 * If non-zero, should contain the offset from the start of css to 619 * a struct cgroup_file field. cgroup will record the handle of 620 * the created file into it. The recorded handle can be used as 621 * long as the containing css remains accessible. 622 */ 623 unsigned int file_offset; 624 625 /* 626 * Fields used for internal bookkeeping. Initialized automatically 627 * during registration. 628 */ 629 struct cgroup_subsys *ss; /* NULL for cgroup core files */ 630 struct list_head node; /* anchored at ss->cfts */ 631 struct kernfs_ops *kf_ops; 632 633 int (*open)(struct kernfs_open_file *of); 634 void (*release)(struct kernfs_open_file *of); 635 636 /* 637 * read_u64() is a shortcut for the common case of returning a 638 * single integer. Use it in place of read() 639 */ 640 u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); 641 /* 642 * read_s64() is a signed version of read_u64() 643 */ 644 s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); 645 646 /* generic seq_file read interface */ 647 int (*seq_show)(struct seq_file *sf, void *v); 648 649 /* optional ops, implement all or none */ 650 void *(*seq_start)(struct seq_file *sf, loff_t *ppos); 651 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); 652 void (*seq_stop)(struct seq_file *sf, void *v); 653 654 /* 655 * write_u64() is a shortcut for the common case of accepting 656 * a single integer (as parsed by simple_strtoull) from 657 * userspace. Use in place of write(); return 0 or error. 658 */ 659 int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, 660 u64 val); 661 /* 662 * write_s64() is a signed version of write_u64() 663 */ 664 int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, 665 s64 val); 666 667 /* 668 * write() is the generic write callback which maps directly to 669 * kernfs write operation and overrides all other operations. 670 * Maximum write size is determined by ->max_write_len. Use 671 * of_css/cft() to access the associated css and cft. 672 */ 673 ssize_t (*write)(struct kernfs_open_file *of, 674 char *buf, size_t nbytes, loff_t off); 675 676 __poll_t (*poll)(struct kernfs_open_file *of, 677 struct poll_table_struct *pt); 678 679#ifdef CONFIG_DEBUG_LOCK_ALLOC 680 struct lock_class_key lockdep_key; 681#endif 682}; 683 684/* 685 * Control Group subsystem type. 686 * See Documentation/admin-guide/cgroup-v1/cgroups.rst for details 687 */ 688struct cgroup_subsys { 689 struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); 690 int (*css_online)(struct cgroup_subsys_state *css); 691 void (*css_offline)(struct cgroup_subsys_state *css); 692 void (*css_released)(struct cgroup_subsys_state *css); 693 void (*css_free)(struct cgroup_subsys_state *css); 694 void (*css_reset)(struct cgroup_subsys_state *css); 695 void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu); 696 int (*css_extra_stat_show)(struct seq_file *seq, 697 struct cgroup_subsys_state *css); 698 int (*css_local_stat_show)(struct seq_file *seq, 699 struct cgroup_subsys_state *css); 700 701 int (*can_attach)(struct cgroup_taskset *tset); 702 void (*cancel_attach)(struct cgroup_taskset *tset); 703 void (*attach)(struct cgroup_taskset *tset); 704 void (*post_attach)(void); 705 int (*can_fork)(struct task_struct *task, 706 struct css_set *cset); 707 void (*cancel_fork)(struct task_struct *task, struct css_set *cset); 708 void (*fork)(struct task_struct *task); 709 void (*exit)(struct task_struct *task); 710 void (*release)(struct task_struct *task); 711 void (*bind)(struct cgroup_subsys_state *root_css); 712 713 bool early_init:1; 714 715 /* 716 * If %true, the controller, on the default hierarchy, doesn't show 717 * up in "cgroup.controllers" or "cgroup.subtree_control", is 718 * implicitly enabled on all cgroups on the default hierarchy, and 719 * bypasses the "no internal process" constraint. This is for 720 * utility type controllers which is transparent to userland. 721 * 722 * An implicit controller can be stolen from the default hierarchy 723 * anytime and thus must be okay with offline csses from previous 724 * hierarchies coexisting with csses for the current one. 725 */ 726 bool implicit_on_dfl:1; 727 728 /* 729 * If %true, the controller, supports threaded mode on the default 730 * hierarchy. In a threaded subtree, both process granularity and 731 * no-internal-process constraint are ignored and a threaded 732 * controllers should be able to handle that. 733 * 734 * Note that as an implicit controller is automatically enabled on 735 * all cgroups on the default hierarchy, it should also be 736 * threaded. implicit && !threaded is not supported. 737 */ 738 bool threaded:1; 739 740 /* the following two fields are initialized automatically during boot */ 741 int id; 742 const char *name; 743 744 /* optional, initialized automatically during boot if not set */ 745 const char *legacy_name; 746 747 /* link to parent, protected by cgroup_lock() */ 748 struct cgroup_root *root; 749 750 /* idr for css->id */ 751 struct idr css_idr; 752 753 /* 754 * List of cftypes. Each entry is the first entry of an array 755 * terminated by zero length name. 756 */ 757 struct list_head cfts; 758 759 /* 760 * Base cftypes which are automatically registered. The two can 761 * point to the same array. 762 */ 763 struct cftype *dfl_cftypes; /* for the default hierarchy */ 764 struct cftype *legacy_cftypes; /* for the legacy hierarchies */ 765 766 /* 767 * A subsystem may depend on other subsystems. When such subsystem 768 * is enabled on a cgroup, the depended-upon subsystems are enabled 769 * together if available. Subsystems enabled due to dependency are 770 * not visible to userland until explicitly enabled. The following 771 * specifies the mask of subsystems that this one depends on. 772 */ 773 unsigned int depends_on; 774}; 775 776extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; 777 778/** 779 * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups 780 * @tsk: target task 781 * 782 * Allows cgroup operations to synchronize against threadgroup changes 783 * using a percpu_rw_semaphore. 784 */ 785static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) 786{ 787 percpu_down_read(&cgroup_threadgroup_rwsem); 788} 789 790/** 791 * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups 792 * @tsk: target task 793 * 794 * Counterpart of cgroup_threadcgroup_change_begin(). 795 */ 796static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) 797{ 798 percpu_up_read(&cgroup_threadgroup_rwsem); 799} 800 801#else /* CONFIG_CGROUPS */ 802 803#define CGROUP_SUBSYS_COUNT 0 804 805static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) 806{ 807 might_sleep(); 808} 809 810static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} 811 812#endif /* CONFIG_CGROUPS */ 813 814#ifdef CONFIG_SOCK_CGROUP_DATA 815 816/* 817 * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains 818 * per-socket cgroup information except for memcg association. 819 * 820 * On legacy hierarchies, net_prio and net_cls controllers directly 821 * set attributes on each sock which can then be tested by the network 822 * layer. On the default hierarchy, each sock is associated with the 823 * cgroup it was created in and the networking layer can match the 824 * cgroup directly. 825 */ 826struct sock_cgroup_data { 827 struct cgroup *cgroup; /* v2 */ 828#ifdef CONFIG_CGROUP_NET_CLASSID 829 u32 classid; /* v1 */ 830#endif 831#ifdef CONFIG_CGROUP_NET_PRIO 832 u16 prioidx; /* v1 */ 833#endif 834}; 835 836static inline u16 sock_cgroup_prioidx(const struct sock_cgroup_data *skcd) 837{ 838#ifdef CONFIG_CGROUP_NET_PRIO 839 return READ_ONCE(skcd->prioidx); 840#else 841 return 1; 842#endif 843} 844 845static inline u32 sock_cgroup_classid(const struct sock_cgroup_data *skcd) 846{ 847#ifdef CONFIG_CGROUP_NET_CLASSID 848 return READ_ONCE(skcd->classid); 849#else 850 return 0; 851#endif 852} 853 854static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, 855 u16 prioidx) 856{ 857#ifdef CONFIG_CGROUP_NET_PRIO 858 WRITE_ONCE(skcd->prioidx, prioidx); 859#endif 860} 861 862static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, 863 u32 classid) 864{ 865#ifdef CONFIG_CGROUP_NET_CLASSID 866 WRITE_ONCE(skcd->classid, classid); 867#endif 868} 869 870#else /* CONFIG_SOCK_CGROUP_DATA */ 871 872struct sock_cgroup_data { 873}; 874 875#endif /* CONFIG_SOCK_CGROUP_DATA */ 876 877#endif /* _LINUX_CGROUP_DEFS_H */ 878