1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_CGROUP_H 3 #define _LINUX_CGROUP_H 4 /* 5 * cgroup interface 6 * 7 * Copyright (C) 2003 BULL SA 8 * Copyright (C) 2004-2006 Silicon Graphics, Inc. 9 * 10 */ 11 12 #include <linux/sched.h> 13 #include <linux/nodemask.h> 14 #include <linux/list.h> 15 #include <linux/rculist.h> 16 #include <linux/cgroupstats.h> 17 #include <linux/fs.h> 18 #include <linux/seq_file.h> 19 #include <linux/kernfs.h> 20 #include <linux/jump_label.h> 21 #include <linux/types.h> 22 #include <linux/notifier.h> 23 #include <linux/ns_common.h> 24 #include <linux/nsproxy.h> 25 #include <linux/user_namespace.h> 26 #include <linux/refcount.h> 27 #include <linux/kernel_stat.h> 28 29 #include <linux/cgroup-defs.h> 30 #include <linux/cgroup_namespace.h> 31 32 struct kernel_clone_args; 33 34 /* 35 * All weight knobs on the default hierarchy should use the following min, 36 * default and max values. The default value is the logarithmic center of 37 * MIN and MAX and allows 100x to be expressed in both directions. 38 */ 39 #define CGROUP_WEIGHT_MIN 1 40 #define CGROUP_WEIGHT_DFL 100 41 #define CGROUP_WEIGHT_MAX 10000 42 43 #ifdef CONFIG_CGROUPS 44 45 /* 46 * To avoid confusing the compiler (and generating warnings) with code 47 * that attempts to access what would be a 0-element array (i.e. sized 48 * to a potentially empty array when CGROUP_SUBSYS_COUNT == 0), this 49 * constant expression can be added. 50 */ 51 #define CGROUP_HAS_SUBSYS_CONFIG (CGROUP_SUBSYS_COUNT > 0) 52 53 enum css_task_iter_flags { 54 CSS_TASK_ITER_PROCS = (1U << 0), /* walk only threadgroup leaders */ 55 CSS_TASK_ITER_THREADED = (1U << 1), /* walk all threaded css_sets in the domain */ 56 CSS_TASK_ITER_SKIPPED = (1U << 16), /* internal flags */ 57 }; 58 59 /* a css_task_iter should be treated as an opaque object */ 60 struct css_task_iter { 61 struct cgroup_subsys *ss; 62 unsigned int flags; 63 64 struct list_head *cset_pos; 65 struct list_head *cset_head; 66 67 struct list_head *tcset_pos; 68 struct list_head *tcset_head; 69 70 struct list_head *task_pos; 71 72 struct list_head *cur_tasks_head; 73 struct css_set *cur_cset; 74 struct css_set *cur_dcset; 75 struct task_struct *cur_task; 76 struct list_head iters_node; /* css_set->task_iters */ 77 }; 78 79 enum cgroup_lifetime_events { 80 CGROUP_LIFETIME_ONLINE, 81 CGROUP_LIFETIME_OFFLINE, 82 }; 83 84 extern struct file_system_type cgroup_fs_type; 85 extern struct cgroup_root cgrp_dfl_root; 86 extern struct css_set init_css_set; 87 extern struct mutex cgroup_mutex; 88 extern spinlock_t css_set_lock; 89 extern struct blocking_notifier_head cgroup_lifetime_notifier; 90 91 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; 92 #include <linux/cgroup_subsys.h> 93 #undef SUBSYS 94 95 #define SUBSYS(_x) \ 96 extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ 97 extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; 98 #include <linux/cgroup_subsys.h> 99 #undef SUBSYS 100 101 /** 102 * cgroup_subsys_enabled - fast test on whether a subsys is enabled 103 * @ss: subsystem in question 104 */ 105 #define cgroup_subsys_enabled(ss) \ 106 static_branch_likely(&ss ## _enabled_key) 107 108 /** 109 * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy 110 * @ss: subsystem in question 111 */ 112 #define cgroup_subsys_on_dfl(ss) \ 113 static_branch_likely(&ss ## _on_dfl_key) 114 115 bool cgroup_on_dfl(const struct cgroup *cgrp); 116 117 bool css_has_online_children(struct cgroup_subsys_state *css); 118 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); 119 struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup, 120 struct cgroup_subsys *ss); 121 struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, 122 struct cgroup_subsys *ss); 123 struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, 124 struct cgroup_subsys *ss); 125 126 struct cgroup *cgroup_get_from_path(const char *path); 127 struct cgroup *cgroup_get_from_fd(int fd); 128 struct cgroup *cgroup_v1v2_get_from_fd(int fd); 129 130 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); 131 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); 132 133 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); 134 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); 135 int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); 136 int cgroup_rm_cftypes(struct cftype *cfts); 137 void cgroup_file_notify(struct cgroup_file *cfile); 138 void cgroup_file_show(struct cgroup_file *cfile, bool show); 139 140 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); 141 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, 142 struct pid *pid, struct task_struct *tsk); 143 144 void cgroup_fork(struct task_struct *p); 145 extern int cgroup_can_fork(struct task_struct *p, 146 struct kernel_clone_args *kargs); 147 extern void cgroup_cancel_fork(struct task_struct *p, 148 struct kernel_clone_args *kargs); 149 extern void cgroup_post_fork(struct task_struct *p, 150 struct kernel_clone_args *kargs); 151 void cgroup_task_exit(struct task_struct *p); 152 void cgroup_task_dead(struct task_struct *p); 153 void cgroup_task_release(struct task_struct *p); 154 void cgroup_task_free(struct task_struct *p); 155 156 int cgroup_init_early(void); 157 int cgroup_init(void); 158 159 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v); 160 161 /* 162 * Iteration helpers and macros. 163 */ 164 165 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, 166 struct cgroup_subsys_state *parent); 167 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, 168 struct cgroup_subsys_state *css); 169 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); 170 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, 171 struct cgroup_subsys_state *css); 172 173 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, 174 struct cgroup_subsys_state **dst_cssp); 175 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, 176 struct cgroup_subsys_state **dst_cssp); 177 178 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, 179 struct css_task_iter *it); 180 struct task_struct *css_task_iter_next(struct css_task_iter *it); 181 void css_task_iter_end(struct css_task_iter *it); 182 183 /** 184 * css_for_each_child - iterate through children of a css 185 * @pos: the css * to use as the loop cursor 186 * @parent: css whose children to walk 187 * 188 * Walk @parent's children. Must be called under rcu_read_lock(). 189 * 190 * If a subsystem synchronizes ->css_online() and the start of iteration, a 191 * css which finished ->css_online() is guaranteed to be visible in the 192 * future iterations and will stay visible until the last reference is put. 193 * A css which hasn't finished ->css_online() or already finished 194 * ->css_offline() may show up during traversal. It's each subsystem's 195 * responsibility to synchronize against on/offlining. 196 * 197 * It is allowed to temporarily drop RCU read lock during iteration. The 198 * caller is responsible for ensuring that @pos remains accessible until 199 * the start of the next iteration by, for example, bumping the css refcnt. 200 */ 201 #define css_for_each_child(pos, parent) \ 202 for ((pos) = css_next_child(NULL, (parent)); (pos); \ 203 (pos) = css_next_child((pos), (parent))) 204 205 /** 206 * css_for_each_descendant_pre - pre-order walk of a css's descendants 207 * @pos: the css * to use as the loop cursor 208 * @root: css whose descendants to walk 209 * 210 * Walk @root's descendants. @root is included in the iteration and the 211 * first node to be visited. Must be called under rcu_read_lock(). 212 * 213 * If a subsystem synchronizes ->css_online() and the start of iteration, a 214 * css which finished ->css_online() is guaranteed to be visible in the 215 * future iterations and will stay visible until the last reference is put. 216 * A css which hasn't finished ->css_online() or already finished 217 * ->css_offline() may show up during traversal. It's each subsystem's 218 * responsibility to synchronize against on/offlining. 219 * 220 * For example, the following guarantees that a descendant can't escape 221 * state updates of its ancestors. 222 * 223 * my_online(@css) 224 * { 225 * Lock @css's parent and @css; 226 * Inherit state from the parent; 227 * Unlock both. 228 * } 229 * 230 * my_update_state(@css) 231 * { 232 * css_for_each_descendant_pre(@pos, @css) { 233 * Lock @pos; 234 * if (@pos == @css) 235 * Update @css's state; 236 * else 237 * Verify @pos is alive and inherit state from its parent; 238 * Unlock @pos; 239 * } 240 * } 241 * 242 * As long as the inheriting step, including checking the parent state, is 243 * enclosed inside @pos locking, double-locking the parent isn't necessary 244 * while inheriting. The state update to the parent is guaranteed to be 245 * visible by walking order and, as long as inheriting operations to the 246 * same @pos are atomic to each other, multiple updates racing each other 247 * still result in the correct state. It's guaranateed that at least one 248 * inheritance happens for any css after the latest update to its parent. 249 * 250 * If checking parent's state requires locking the parent, each inheriting 251 * iteration should lock and unlock both @pos->parent and @pos. 252 * 253 * Alternatively, a subsystem may choose to use a single global lock to 254 * synchronize ->css_online() and ->css_offline() against tree-walking 255 * operations. 256 * 257 * It is allowed to temporarily drop RCU read lock during iteration. The 258 * caller is responsible for ensuring that @pos remains accessible until 259 * the start of the next iteration by, for example, bumping the css refcnt. 260 */ 261 #define css_for_each_descendant_pre(pos, css) \ 262 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ 263 (pos) = css_next_descendant_pre((pos), (css))) 264 265 /** 266 * css_for_each_descendant_post - post-order walk of a css's descendants 267 * @pos: the css * to use as the loop cursor 268 * @css: css whose descendants to walk 269 * 270 * Similar to css_for_each_descendant_pre() but performs post-order 271 * traversal instead. @root is included in the iteration and the last 272 * node to be visited. 273 * 274 * If a subsystem synchronizes ->css_online() and the start of iteration, a 275 * css which finished ->css_online() is guaranteed to be visible in the 276 * future iterations and will stay visible until the last reference is put. 277 * A css which hasn't finished ->css_online() or already finished 278 * ->css_offline() may show up during traversal. It's each subsystem's 279 * responsibility to synchronize against on/offlining. 280 * 281 * Note that the walk visibility guarantee example described in pre-order 282 * walk doesn't apply the same to post-order walks. 283 */ 284 #define css_for_each_descendant_post(pos, css) \ 285 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ 286 (pos) = css_next_descendant_post((pos), (css))) 287 288 /* iterate over child cgrps, lock should be held throughout iteration */ 289 #define cgroup_for_each_live_child(child, cgrp) \ 290 list_for_each_entry((child), &(cgrp)->self.children, self.sibling) \ 291 if (({ lockdep_assert_held(&cgroup_mutex); \ 292 cgroup_is_dead(child); })) \ 293 ; \ 294 else 295 296 /* walk live descendants in pre order */ 297 #define cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) \ 298 css_for_each_descendant_pre((d_css), cgroup_css((cgrp), NULL)) \ 299 if (({ lockdep_assert_held(&cgroup_mutex); \ 300 (dsct) = (d_css)->cgroup; \ 301 cgroup_is_dead(dsct); })) \ 302 ; \ 303 else 304 305 /* walk live descendants in postorder */ 306 #define cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) \ 307 css_for_each_descendant_post((d_css), cgroup_css((cgrp), NULL)) \ 308 if (({ lockdep_assert_held(&cgroup_mutex); \ 309 (dsct) = (d_css)->cgroup; \ 310 cgroup_is_dead(dsct); })) \ 311 ; \ 312 else 313 314 /** 315 * cgroup_taskset_for_each - iterate cgroup_taskset 316 * @task: the loop cursor 317 * @dst_css: the destination css 318 * @tset: taskset to iterate 319 * 320 * @tset may contain multiple tasks and they may belong to multiple 321 * processes. 322 * 323 * On the v2 hierarchy, there may be tasks from multiple processes and they 324 * may not share the source or destination csses. 325 * 326 * On traditional hierarchies, when there are multiple tasks in @tset, if a 327 * task of a process is in @tset, all tasks of the process are in @tset. 328 * Also, all are guaranteed to share the same source and destination csses. 329 * 330 * Iteration is not in any specific order. 331 */ 332 #define cgroup_taskset_for_each(task, dst_css, tset) \ 333 for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ 334 (task); \ 335 (task) = cgroup_taskset_next((tset), &(dst_css))) 336 337 /** 338 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset 339 * @leader: the loop cursor 340 * @dst_css: the destination css 341 * @tset: taskset to iterate 342 * 343 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset 344 * may not contain any. 345 */ 346 #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ 347 for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ 348 (leader); \ 349 (leader) = cgroup_taskset_next((tset), &(dst_css))) \ 350 if ((leader) != (leader)->group_leader) \ 351 ; \ 352 else 353 354 /* 355 * Inline functions. 356 */ 357 358 #ifdef CONFIG_DEBUG_CGROUP_REF 359 void css_get(struct cgroup_subsys_state *css); 360 void css_get_many(struct cgroup_subsys_state *css, unsigned int n); 361 bool css_tryget(struct cgroup_subsys_state *css); 362 bool css_tryget_online(struct cgroup_subsys_state *css); 363 void css_put(struct cgroup_subsys_state *css); 364 void css_put_many(struct cgroup_subsys_state *css, unsigned int n); 365 #else 366 #define CGROUP_REF_FN_ATTRS static inline 367 #define CGROUP_REF_EXPORT(fn) 368 #include <linux/cgroup_refcnt.h> 369 #endif 370 371 static inline u64 cgroup_id(const struct cgroup *cgrp) 372 { 373 return cgrp->kn->id; 374 } 375 376 /** 377 * cgroup_css - obtain a cgroup's css for the specified subsystem 378 * @cgrp: the cgroup of interest 379 * @ss: the subsystem of interest (%NULL returns @cgrp->self) 380 * 381 * Return @cgrp's css (cgroup_subsys_state) associated with @ss. This 382 * function must be called either under cgroup_mutex or rcu_read_lock() and 383 * the caller is responsible for pinning the returned css if it wants to 384 * keep accessing it outside the said locks. This function may return 385 * %NULL if @cgrp doesn't have @subsys_id enabled. 386 */ 387 static inline struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp, 388 struct cgroup_subsys *ss) 389 { 390 if (CGROUP_HAS_SUBSYS_CONFIG && ss) 391 return rcu_dereference_check(cgrp->subsys[ss->id], 392 lockdep_is_held(&cgroup_mutex)); 393 else 394 return &cgrp->self; 395 } 396 397 /** 398 * css_is_dying - test whether the specified css is dying 399 * @css: target css 400 * 401 * Test whether @css is in the process of offlining or already offline. In 402 * most cases, ->css_online() and ->css_offline() callbacks should be 403 * enough; however, the actual offline operations are RCU delayed and this 404 * test returns %true also when @css is scheduled to be offlined. 405 * 406 * This is useful, for example, when the use case requires synchronous 407 * behavior with respect to cgroup removal. cgroup removal schedules css 408 * offlining but the css can seem alive while the operation is being 409 * delayed. If the delay affects user visible semantics, this test can be 410 * used to resolve the situation. 411 */ 412 static inline bool css_is_dying(struct cgroup_subsys_state *css) 413 { 414 return css->flags & CSS_DYING; 415 } 416 417 static inline bool css_is_online(struct cgroup_subsys_state *css) 418 { 419 return css->flags & CSS_ONLINE; 420 } 421 422 static inline bool css_is_self(struct cgroup_subsys_state *css) 423 { 424 if (css == &css->cgroup->self) { 425 /* cgroup::self should not have subsystem association */ 426 WARN_ON(css->ss != NULL); 427 return true; 428 } 429 430 return false; 431 } 432 433 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 434 { 435 return !(cgrp->self.flags & CSS_ONLINE); 436 } 437 438 static inline void cgroup_get(struct cgroup *cgrp) 439 { 440 css_get(&cgrp->self); 441 } 442 443 static inline bool cgroup_tryget(struct cgroup *cgrp) 444 { 445 return css_tryget(&cgrp->self); 446 } 447 448 static inline void cgroup_put(struct cgroup *cgrp) 449 { 450 css_put(&cgrp->self); 451 } 452 453 static inline void cgroup_lock(void) 454 { 455 mutex_lock(&cgroup_mutex); 456 } 457 458 static inline void cgroup_unlock(void) 459 { 460 mutex_unlock(&cgroup_mutex); 461 } 462 463 /** 464 * task_css_set_check - obtain a task's css_set with extra access conditions 465 * @task: the task to obtain css_set for 466 * @__c: extra condition expression to be passed to rcu_dereference_check() 467 * 468 * A task's css_set is RCU protected, initialized and exited while holding 469 * task_lock(), and can only be modified while holding both cgroup_mutex 470 * and task_lock() while the task is alive. This macro verifies that the 471 * caller is inside proper critical section and returns @task's css_set. 472 * 473 * The caller can also specify additional allowed conditions via @__c, such 474 * as locks used during the cgroup_subsys::attach() methods. 475 */ 476 #ifdef CONFIG_PROVE_RCU 477 #define task_css_set_check(task, __c) \ 478 rcu_dereference_check((task)->cgroups, \ 479 rcu_read_lock_sched_held() || \ 480 lockdep_is_held(&cgroup_mutex) || \ 481 lockdep_is_held(&css_set_lock) || \ 482 ((task)->flags & PF_EXITING) || (__c)) 483 #else 484 #define task_css_set_check(task, __c) \ 485 rcu_dereference((task)->cgroups) 486 #endif 487 488 /** 489 * task_css_check - obtain css for (task, subsys) w/ extra access conds 490 * @task: the target task 491 * @subsys_id: the target subsystem ID 492 * @__c: extra condition expression to be passed to rcu_dereference_check() 493 * 494 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The 495 * synchronization rules are the same as task_css_set_check(). 496 */ 497 #define task_css_check(task, subsys_id, __c) \ 498 task_css_set_check((task), (__c))->subsys[(subsys_id)] 499 500 /** 501 * task_css_set - obtain a task's css_set 502 * @task: the task to obtain css_set for 503 * 504 * See task_css_set_check(). 505 */ 506 static inline struct css_set *task_css_set(struct task_struct *task) 507 { 508 return task_css_set_check(task, false); 509 } 510 511 /** 512 * task_css - obtain css for (task, subsys) 513 * @task: the target task 514 * @subsys_id: the target subsystem ID 515 * 516 * See task_css_check(). 517 */ 518 static inline struct cgroup_subsys_state *task_css(struct task_struct *task, 519 int subsys_id) 520 { 521 return task_css_check(task, subsys_id, false); 522 } 523 524 /** 525 * task_get_css - find and get the css for (task, subsys) 526 * @task: the target task 527 * @subsys_id: the target subsystem ID 528 * 529 * Find the css for the (@task, @subsys_id) combination, increment a 530 * reference on and return it. This function is guaranteed to return a 531 * valid css. The returned css may already have been offlined. 532 */ 533 static inline struct cgroup_subsys_state * 534 task_get_css(struct task_struct *task, int subsys_id) 535 { 536 struct cgroup_subsys_state *css; 537 538 rcu_read_lock(); 539 while (true) { 540 css = task_css(task, subsys_id); 541 /* 542 * Can't use css_tryget_online() here. A task which has 543 * PF_EXITING set may stay associated with an offline css. 544 * If such task calls this function, css_tryget_online() 545 * will keep failing. 546 */ 547 if (likely(css_tryget(css))) 548 break; 549 cpu_relax(); 550 } 551 rcu_read_unlock(); 552 return css; 553 } 554 555 /** 556 * task_css_is_root - test whether a task belongs to the root css 557 * @task: the target task 558 * @subsys_id: the target subsystem ID 559 * 560 * Test whether @task belongs to the root css on the specified subsystem. 561 * May be invoked in any context. 562 */ 563 static inline bool task_css_is_root(struct task_struct *task, int subsys_id) 564 { 565 return task_css_check(task, subsys_id, true) == 566 init_css_set.subsys[subsys_id]; 567 } 568 569 static inline struct cgroup *task_cgroup(struct task_struct *task, 570 int subsys_id) 571 { 572 return task_css(task, subsys_id)->cgroup; 573 } 574 575 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task) 576 { 577 return task_css_set(task)->dfl_cgrp; 578 } 579 580 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp) 581 { 582 struct cgroup_subsys_state *parent_css = cgrp->self.parent; 583 584 if (parent_css) 585 return container_of(parent_css, struct cgroup, self); 586 return NULL; 587 } 588 589 /** 590 * cgroup_is_descendant - test ancestry 591 * @cgrp: the cgroup to be tested 592 * @ancestor: possible ancestor of @cgrp 593 * 594 * Test whether @cgrp is a descendant of @ancestor. It also returns %true 595 * if @cgrp == @ancestor. This function is safe to call as long as @cgrp 596 * and @ancestor are accessible. 597 */ 598 static inline bool cgroup_is_descendant(struct cgroup *cgrp, 599 struct cgroup *ancestor) 600 { 601 if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) 602 return false; 603 return cgrp->ancestors[ancestor->level] == ancestor; 604 } 605 606 /** 607 * cgroup_ancestor - find ancestor of cgroup 608 * @cgrp: cgroup to find ancestor of 609 * @ancestor_level: level of ancestor to find starting from root 610 * 611 * Find ancestor of cgroup at specified level starting from root if it exists 612 * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at 613 * @ancestor_level. 614 * 615 * This function is safe to call as long as @cgrp is accessible. 616 */ 617 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp, 618 int ancestor_level) 619 { 620 if (ancestor_level < 0 || ancestor_level > cgrp->level) 621 return NULL; 622 return cgrp->ancestors[ancestor_level]; 623 } 624 625 /** 626 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry 627 * @task: the task to be tested 628 * @ancestor: possible ancestor of @task's cgroup 629 * 630 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor. 631 * It follows all the same rules as cgroup_is_descendant, and only applies 632 * to the default hierarchy. 633 */ 634 static inline bool task_under_cgroup_hierarchy(struct task_struct *task, 635 struct cgroup *ancestor) 636 { 637 struct css_set *cset = task_css_set(task); 638 639 return cgroup_is_descendant(cset->dfl_cgrp, ancestor); 640 } 641 642 /* no synchronization, the result can only be used as a hint */ 643 static inline bool cgroup_is_populated(struct cgroup *cgrp) 644 { 645 return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children + 646 cgrp->nr_populated_threaded_children; 647 } 648 649 /* returns ino associated with a cgroup */ 650 static inline ino_t cgroup_ino(struct cgroup *cgrp) 651 { 652 return kernfs_ino(cgrp->kn); 653 } 654 655 /* cft/css accessors for cftype->write() operation */ 656 static inline struct cftype *of_cft(struct kernfs_open_file *of) 657 { 658 return of->kn->priv; 659 } 660 661 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); 662 663 /* cft/css accessors for cftype->seq_*() operations */ 664 static inline struct cftype *seq_cft(struct seq_file *seq) 665 { 666 return of_cft(seq->private); 667 } 668 669 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) 670 { 671 return of_css(seq->private); 672 } 673 674 /* 675 * Name / path handling functions. All are thin wrappers around the kernfs 676 * counterparts and can be called under any context. 677 */ 678 679 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) 680 { 681 return kernfs_name(cgrp->kn, buf, buflen); 682 } 683 684 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) 685 { 686 return kernfs_path(cgrp->kn, buf, buflen); 687 } 688 689 static inline void pr_cont_cgroup_name(struct cgroup *cgrp) 690 { 691 pr_cont_kernfs_name(cgrp->kn); 692 } 693 694 static inline void pr_cont_cgroup_path(struct cgroup *cgrp) 695 { 696 pr_cont_kernfs_path(cgrp->kn); 697 } 698 699 bool cgroup_psi_enabled(void); 700 701 static inline void cgroup_init_kthreadd(void) 702 { 703 /* 704 * kthreadd is inherited by all kthreads, keep it in the root so 705 * that the new kthreads are guaranteed to stay in the root until 706 * initialization is finished. 707 */ 708 current->no_cgroup_migration = 1; 709 } 710 711 static inline void cgroup_kthread_ready(void) 712 { 713 /* 714 * This kthread finished initialization. The creator should have 715 * set PF_NO_SETAFFINITY if this kthread should stay in the root. 716 */ 717 current->no_cgroup_migration = 0; 718 } 719 720 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen); 721 struct cgroup *__cgroup_get_from_id(u64 id); 722 struct cgroup *cgroup_get_from_id(u64 id); 723 #else /* !CONFIG_CGROUPS */ 724 725 struct cgroup_subsys_state; 726 struct cgroup; 727 728 static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; } 729 static inline void css_get(struct cgroup_subsys_state *css) {} 730 static inline void css_put(struct cgroup_subsys_state *css) {} 731 static inline void cgroup_lock(void) {} 732 static inline void cgroup_unlock(void) {} 733 static inline int cgroup_attach_task_all(struct task_struct *from, 734 struct task_struct *t) { return 0; } 735 static inline int cgroupstats_build(struct cgroupstats *stats, 736 struct dentry *dentry) { return -EINVAL; } 737 738 static inline void cgroup_fork(struct task_struct *p) {} 739 static inline int cgroup_can_fork(struct task_struct *p, 740 struct kernel_clone_args *kargs) { return 0; } 741 static inline void cgroup_cancel_fork(struct task_struct *p, 742 struct kernel_clone_args *kargs) {} 743 static inline void cgroup_post_fork(struct task_struct *p, 744 struct kernel_clone_args *kargs) {} 745 static inline void cgroup_task_exit(struct task_struct *p) {} 746 static inline void cgroup_task_dead(struct task_struct *p) {} 747 static inline void cgroup_task_release(struct task_struct *p) {} 748 static inline void cgroup_task_free(struct task_struct *p) {} 749 750 static inline int cgroup_init_early(void) { return 0; } 751 static inline int cgroup_init(void) { return 0; } 752 static inline void cgroup_init_kthreadd(void) {} 753 static inline void cgroup_kthread_ready(void) {} 754 755 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp) 756 { 757 return NULL; 758 } 759 760 static inline bool cgroup_psi_enabled(void) 761 { 762 return false; 763 } 764 765 static inline bool task_under_cgroup_hierarchy(struct task_struct *task, 766 struct cgroup *ancestor) 767 { 768 return true; 769 } 770 771 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) 772 {} 773 #endif /* !CONFIG_CGROUPS */ 774 775 #ifdef CONFIG_CGROUPS 776 /* 777 * cgroup scalable recursive statistics. 778 */ 779 void css_rstat_updated(struct cgroup_subsys_state *css, int cpu); 780 void css_rstat_flush(struct cgroup_subsys_state *css); 781 782 /* 783 * Basic resource stats. 784 */ 785 #ifdef CONFIG_CGROUP_CPUACCT 786 void cpuacct_charge(struct task_struct *tsk, u64 cputime); 787 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val); 788 #else 789 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} 790 static inline void cpuacct_account_field(struct task_struct *tsk, int index, 791 u64 val) {} 792 #endif 793 794 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec); 795 void __cgroup_account_cputime_field(struct cgroup *cgrp, 796 enum cpu_usage_stat index, u64 delta_exec); 797 798 static inline void cgroup_account_cputime(struct task_struct *task, 799 u64 delta_exec) 800 { 801 struct cgroup *cgrp; 802 803 cpuacct_charge(task, delta_exec); 804 805 cgrp = task_dfl_cgroup(task); 806 if (cgroup_parent(cgrp)) 807 __cgroup_account_cputime(cgrp, delta_exec); 808 } 809 810 static inline void cgroup_account_cputime_field(struct task_struct *task, 811 enum cpu_usage_stat index, 812 u64 delta_exec) 813 { 814 struct cgroup *cgrp; 815 816 cpuacct_account_field(task, index, delta_exec); 817 818 cgrp = task_dfl_cgroup(task); 819 if (cgroup_parent(cgrp)) 820 __cgroup_account_cputime_field(cgrp, index, delta_exec); 821 } 822 823 #else /* CONFIG_CGROUPS */ 824 825 static inline void cgroup_account_cputime(struct task_struct *task, 826 u64 delta_exec) {} 827 static inline void cgroup_account_cputime_field(struct task_struct *task, 828 enum cpu_usage_stat index, 829 u64 delta_exec) {} 830 831 #endif /* CONFIG_CGROUPS */ 832 833 /* 834 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data 835 * definition in cgroup-defs.h. 836 */ 837 #ifdef CONFIG_SOCK_CGROUP_DATA 838 839 void cgroup_sk_alloc(struct sock_cgroup_data *skcd); 840 void cgroup_sk_clone(struct sock_cgroup_data *skcd); 841 void cgroup_sk_free(struct sock_cgroup_data *skcd); 842 843 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) 844 { 845 return skcd->cgroup; 846 } 847 848 #else /* CONFIG_CGROUP_DATA */ 849 850 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} 851 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {} 852 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} 853 854 #endif /* CONFIG_CGROUP_DATA */ 855 856 #ifdef CONFIG_CGROUPS 857 858 void cgroup_enter_frozen(void); 859 void cgroup_leave_frozen(bool always_leave); 860 void cgroup_update_frozen(struct cgroup *cgrp); 861 void cgroup_freeze(struct cgroup *cgrp, bool freeze); 862 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src, 863 struct cgroup *dst); 864 865 static inline bool cgroup_task_frozen(struct task_struct *task) 866 { 867 return task->frozen; 868 } 869 870 #else /* !CONFIG_CGROUPS */ 871 872 static inline void cgroup_enter_frozen(void) { } 873 static inline void cgroup_leave_frozen(bool always_leave) { } 874 static inline bool cgroup_task_frozen(struct task_struct *task) 875 { 876 return false; 877 } 878 879 #endif /* !CONFIG_CGROUPS */ 880 881 #ifdef CONFIG_CGROUP_BPF 882 static inline void cgroup_bpf_get(struct cgroup *cgrp) 883 { 884 percpu_ref_get(&cgrp->bpf.refcnt); 885 } 886 887 static inline void cgroup_bpf_put(struct cgroup *cgrp) 888 { 889 percpu_ref_put(&cgrp->bpf.refcnt); 890 } 891 892 #else /* CONFIG_CGROUP_BPF */ 893 894 static inline void cgroup_bpf_get(struct cgroup *cgrp) {} 895 static inline void cgroup_bpf_put(struct cgroup *cgrp) {} 896 897 #endif /* CONFIG_CGROUP_BPF */ 898 899 struct cgroup *task_get_cgroup1(struct task_struct *tsk, int hierarchy_id); 900 901 struct cgroup_of_peak *of_peak(struct kernfs_open_file *of); 902 903 #endif /* _LINUX_CGROUP_H */ 904