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