1 #ifndef _LINUX_CGROUP_H
2 #define _LINUX_CGROUP_H
6 * Copyright (C) 2003 BULL SA
7 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
11 #include <linux/sched.h>
12 #include <linux/cpumask.h>
13 #include <linux/nodemask.h>
14 #include <linux/rcupdate.h>
15 #include <linux/rculist.h>
16 #include <linux/cgroupstats.h>
17 #include <linux/prio_heap.h>
18 #include <linux/rwsem.h>
19 #include <linux/idr.h>
20 #include <linux/workqueue.h>
22 #include <linux/percpu-refcount.h>
23 #include <linux/seq_file.h>
24 #include <linux/kernfs.h>
33 extern int cgroup_init_early(void);
34 extern int cgroup_init(void);
35 extern void cgroup_fork(struct task_struct *p);
36 extern void cgroup_post_fork(struct task_struct *p);
37 extern void cgroup_exit(struct task_struct *p, int run_callbacks);
38 extern int cgroupstats_build(struct cgroupstats *stats,
39 struct dentry *dentry);
41 extern int proc_cgroup_show(struct seq_file *, void *);
43 /* define the enumeration of all cgroup subsystems */
44 #define SUBSYS(_x) _x ## _cgrp_id,
45 enum cgroup_subsys_id {
46 #include <linux/cgroup_subsys.h>
51 /* Per-subsystem/per-cgroup state maintained by the system. */
52 struct cgroup_subsys_state {
53 /* the cgroup that this css is attached to */
54 struct cgroup *cgroup;
56 /* the cgroup subsystem that this css is attached to */
57 struct cgroup_subsys *ss;
59 /* reference count - access via css_[try]get() and css_put() */
60 struct percpu_ref refcnt;
63 struct cgroup_subsys_state *parent;
67 /* percpu_ref killing and RCU release */
68 struct rcu_head rcu_head;
69 struct work_struct destroy_work;
72 /* bits in struct cgroup_subsys_state flags field */
74 CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */
75 CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */
79 * css_get - obtain a reference on the specified css
82 * The caller must already have a reference.
84 static inline void css_get(struct cgroup_subsys_state *css)
86 /* We don't need to reference count the root state */
87 if (!(css->flags & CSS_ROOT))
88 percpu_ref_get(&css->refcnt);
92 * css_tryget - try to obtain a reference on the specified css
95 * Obtain a reference on @css if it's alive. The caller naturally needs to
96 * ensure that @css is accessible but doesn't have to be holding a
97 * reference on it - IOW, RCU protected access is good enough for this
98 * function. Returns %true if a reference count was successfully obtained;
101 static inline bool css_tryget(struct cgroup_subsys_state *css)
103 if (css->flags & CSS_ROOT)
105 return percpu_ref_tryget(&css->refcnt);
109 * css_put - put a css reference
112 * Put a reference obtained via css_get() and css_tryget().
114 static inline void css_put(struct cgroup_subsys_state *css)
116 if (!(css->flags & CSS_ROOT))
117 percpu_ref_put(&css->refcnt);
120 /* bits in struct cgroup flags field */
122 /* Control Group is dead */
125 * Control Group has previously had a child cgroup or a task,
126 * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set)
129 /* Control Group requires release notifications to userspace */
130 CGRP_NOTIFY_ON_RELEASE,
132 * Clone the parent's configuration when creating a new child
133 * cpuset cgroup. For historical reasons, this option can be
134 * specified at mount time and thus is implemented here.
136 CGRP_CPUSET_CLONE_CHILDREN,
137 /* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */
142 struct rcu_head rcu_head;
147 unsigned long flags; /* "unsigned long" so bitops work */
150 * idr allocated in-hierarchy ID.
152 * The ID of the root cgroup is always 0, and a new cgroup
153 * will be assigned with a smallest available ID.
155 * Allocating/Removing ID must be protected by cgroup_mutex.
159 /* the number of attached css's */
165 * We link our 'sibling' struct into our parent's 'children'.
166 * Our children link their 'sibling' into our 'children'.
168 struct list_head sibling; /* my parent's children */
169 struct list_head children; /* my children */
171 struct cgroup *parent; /* my parent */
172 struct kernfs_node *kn; /* cgroup kernfs entry */
175 * Monotonically increasing unique serial number which defines a
176 * uniform order among all cgroups. It's guaranteed that all
177 * ->children lists are in the ascending order of ->serial_nr.
178 * It's used to allow interrupting and resuming iterations.
183 * This is a copy of dentry->d_name, and it's needed because
184 * we can't use dentry->d_name in cgroup_path().
186 * You must acquire rcu_read_lock() to access cgrp->name, and
187 * the only place that can change it is rename(), which is
188 * protected by parent dir's i_mutex.
190 * Normally you should use cgroup_name() wrapper rather than
191 * access it directly.
193 struct cgroup_name __rcu *name;
195 /* Private pointers for each registered subsystem */
196 struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT];
198 struct cgroupfs_root *root;
201 * List of cgrp_cset_links pointing at css_sets with tasks in this
202 * cgroup. Protected by css_set_lock.
204 struct list_head cset_links;
207 * Linked list running through all cgroups that can
208 * potentially be reaped by the release agent. Protected by
211 struct list_head release_list;
214 * list of pidlists, up to two for each namespace (one for procs, one
215 * for tasks); created on demand.
217 struct list_head pidlists;
218 struct mutex pidlist_mutex;
220 /* dummy css with NULL ->ss, points back to this cgroup */
221 struct cgroup_subsys_state dummy_css;
223 /* For css percpu_ref killing and RCU-protected deletion */
224 struct rcu_head rcu_head;
225 struct work_struct destroy_work;
228 #define MAX_CGROUP_ROOT_NAMELEN 64
230 /* cgroupfs_root->flags */
233 * Unfortunately, cgroup core and various controllers are riddled
234 * with idiosyncrasies and pointless options. The following flag,
235 * when set, will force sane behavior - some options are forced on,
236 * others are disallowed, and some controllers will change their
237 * hierarchical or other behaviors.
239 * The set of behaviors affected by this flag are still being
240 * determined and developed and the mount option for this flag is
241 * prefixed with __DEVEL__. The prefix will be dropped once we
242 * reach the point where all behaviors are compatible with the
243 * planned unified hierarchy, which will automatically turn on this
246 * The followings are the behaviors currently affected this flag.
248 * - Mount options "noprefix" and "clone_children" are disallowed.
249 * Also, cgroupfs file cgroup.clone_children is not created.
251 * - When mounting an existing superblock, mount options should
254 * - Remount is disallowed.
256 * - rename(2) is disallowed.
258 * - "tasks" is removed. Everything should be at process
259 * granularity. Use "cgroup.procs" instead.
261 * - "cgroup.procs" is not sorted. pids will be unique unless they
262 * got recycled inbetween reads.
264 * - "release_agent" and "notify_on_release" are removed.
265 * Replacement notification mechanism will be implemented.
267 * - "xattr" mount option is deprecated. kernfs always enables it.
269 * - cpuset: tasks will be kept in empty cpusets when hotplug happens
270 * and take masks of ancestors with non-empty cpus/mems, instead of
271 * being moved to an ancestor.
273 * - cpuset: a task can be moved into an empty cpuset, and again it
274 * takes masks of ancestors.
276 * - memcg: use_hierarchy is on by default and the cgroup file for
277 * the flag is not created.
279 * - blkcg: blk-throttle becomes properly hierarchical.
281 CGRP_ROOT_SANE_BEHAVIOR = (1 << 0),
283 CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */
284 CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */
286 /* mount options live below bit 16 */
287 CGRP_ROOT_OPTION_MASK = (1 << 16) - 1,
289 CGRP_ROOT_SUBSYS_BOUND = (1 << 16), /* subsystems finished binding */
293 * A cgroupfs_root represents the root of a cgroup hierarchy, and may be
294 * associated with a kernfs_root to form an active hierarchy. This is
295 * internal to cgroup core. Don't access directly from controllers.
297 struct cgroupfs_root {
298 struct kernfs_root *kf_root;
300 /* The bitmask of subsystems attached to this hierarchy */
301 unsigned long subsys_mask;
305 /* Unique id for this hierarchy. */
308 /* The root cgroup for this hierarchy */
309 struct cgroup top_cgroup;
311 /* Tracks how many cgroups are currently defined in hierarchy.*/
312 int number_of_cgroups;
314 /* A list running through the active hierarchies */
315 struct list_head root_list;
317 /* Hierarchy-specific flags */
320 /* IDs for cgroups in this hierarchy */
321 struct idr cgroup_idr;
323 /* The path to use for release notifications. */
324 char release_agent_path[PATH_MAX];
326 /* The name for this hierarchy - may be empty */
327 char name[MAX_CGROUP_ROOT_NAMELEN];
331 * A css_set is a structure holding pointers to a set of
332 * cgroup_subsys_state objects. This saves space in the task struct
333 * object and speeds up fork()/exit(), since a single inc/dec and a
334 * list_add()/del() can bump the reference count on the entire cgroup
340 /* Reference count */
344 * List running through all cgroup groups in the same hash
345 * slot. Protected by css_set_lock
347 struct hlist_node hlist;
350 * List running through all tasks using this cgroup
351 * group. Protected by css_set_lock
353 struct list_head tasks;
356 * List of cgrp_cset_links pointing at cgroups referenced from this
357 * css_set. Protected by css_set_lock.
359 struct list_head cgrp_links;
362 * Set of subsystem states, one for each subsystem. This array is
363 * immutable after creation apart from the init_css_set during
364 * subsystem registration (at boot time).
366 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
368 /* For RCU-protected deletion */
369 struct rcu_head rcu_head;
373 * struct cftype: handler definitions for cgroup control files
375 * When reading/writing to a file:
376 * - the cgroup to use is file->f_dentry->d_parent->d_fsdata
377 * - the 'cftype' of the file is file->f_dentry->d_fsdata
382 CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */
383 CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */
384 CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */
385 CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */
388 #define MAX_CFTYPE_NAME 64
392 * By convention, the name should begin with the name of the
393 * subsystem, followed by a period. Zero length string indicates
394 * end of cftype array.
396 char name[MAX_CFTYPE_NAME];
399 * If not 0, file mode is set to this value, otherwise it will
400 * be figured out automatically
405 * The maximum length of string, excluding trailing nul, that can
406 * be passed to write_string. If < PAGE_SIZE-1, PAGE_SIZE-1 is
409 size_t max_write_len;
415 * Fields used for internal bookkeeping. Initialized automatically
416 * during registration.
418 struct cgroup_subsys *ss; /* NULL for cgroup core files */
419 struct list_head node; /* anchored at ss->cfts */
420 struct kernfs_ops *kf_ops;
423 * read_u64() is a shortcut for the common case of returning a
424 * single integer. Use it in place of read()
426 u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft);
428 * read_s64() is a signed version of read_u64()
430 s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft);
432 /* generic seq_file read interface */
433 int (*seq_show)(struct seq_file *sf, void *v);
435 /* optional ops, implement all or none */
436 void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
437 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
438 void (*seq_stop)(struct seq_file *sf, void *v);
441 * write_u64() is a shortcut for the common case of accepting
442 * a single integer (as parsed by simple_strtoull) from
443 * userspace. Use in place of write(); return 0 or error.
445 int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft,
448 * write_s64() is a signed version of write_u64()
450 int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft,
454 * write_string() is passed a nul-terminated kernelspace
455 * buffer of maximum length determined by max_write_len.
456 * Returns 0 or -ve error code.
458 int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft,
461 * trigger() callback can be used to get some kick from the
462 * userspace, when the actual string written is not important
463 * at all. The private field can be used to determine the
464 * kick type for multiplexing.
466 int (*trigger)(struct cgroup_subsys_state *css, unsigned int event);
468 #ifdef CONFIG_DEBUG_LOCK_ALLOC
469 struct lock_class_key lockdep_key;
474 * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This
475 * function can be called as long as @cgrp is accessible.
477 static inline bool cgroup_sane_behavior(const struct cgroup *cgrp)
479 return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR;
482 /* Caller should hold rcu_read_lock() */
483 static inline const char *cgroup_name(const struct cgroup *cgrp)
485 return rcu_dereference(cgrp->name)->name;
488 /* returns ino associated with a cgroup, 0 indicates unmounted root */
489 static inline ino_t cgroup_ino(struct cgroup *cgrp)
492 return cgrp->kn->ino;
497 static inline struct cftype *seq_cft(struct seq_file *seq)
499 struct kernfs_open_file *of = seq->private;
504 struct cgroup_subsys_state *seq_css(struct seq_file *seq);
506 int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
507 int cgroup_rm_cftypes(struct cftype *cfts);
509 bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
511 int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
512 int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
514 int cgroup_task_count(const struct cgroup *cgrp);
517 * Control Group taskset, used to pass around set of tasks to cgroup_subsys
520 struct cgroup_taskset;
521 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
522 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
523 struct cgroup_subsys_state *cgroup_taskset_cur_css(struct cgroup_taskset *tset,
525 int cgroup_taskset_size(struct cgroup_taskset *tset);
528 * cgroup_taskset_for_each - iterate cgroup_taskset
529 * @task: the loop cursor
530 * @skip_css: skip if task's css matches this, %NULL to iterate through all
531 * @tset: taskset to iterate
533 #define cgroup_taskset_for_each(task, skip_css, tset) \
534 for ((task) = cgroup_taskset_first((tset)); (task); \
535 (task) = cgroup_taskset_next((tset))) \
537 cgroup_taskset_cur_css((tset), \
538 (skip_css)->ss->id) != (skip_css))
541 * Control Group subsystem type.
542 * See Documentation/cgroups/cgroups.txt for details
545 struct cgroup_subsys {
546 struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css);
547 int (*css_online)(struct cgroup_subsys_state *css);
548 void (*css_offline)(struct cgroup_subsys_state *css);
549 void (*css_free)(struct cgroup_subsys_state *css);
551 int (*can_attach)(struct cgroup_subsys_state *css,
552 struct cgroup_taskset *tset);
553 void (*cancel_attach)(struct cgroup_subsys_state *css,
554 struct cgroup_taskset *tset);
555 void (*attach)(struct cgroup_subsys_state *css,
556 struct cgroup_taskset *tset);
557 void (*fork)(struct task_struct *task);
558 void (*exit)(struct cgroup_subsys_state *css,
559 struct cgroup_subsys_state *old_css,
560 struct task_struct *task);
561 void (*bind)(struct cgroup_subsys_state *root_css);
567 * If %false, this subsystem is properly hierarchical -
568 * configuration, resource accounting and restriction on a parent
569 * cgroup cover those of its children. If %true, hierarchy support
570 * is broken in some ways - some subsystems ignore hierarchy
571 * completely while others are only implemented half-way.
573 * It's now disallowed to create nested cgroups if the subsystem is
574 * broken and cgroup core will emit a warning message on such
575 * cases. Eventually, all subsystems will be made properly
576 * hierarchical and this will go away.
578 bool broken_hierarchy;
579 bool warned_broken_hierarchy;
581 /* the following two fields are initialized automtically during boot */
583 #define MAX_CGROUP_TYPE_NAMELEN 32
586 /* link to parent, protected by cgroup_lock() */
587 struct cgroupfs_root *root;
590 * List of cftypes. Each entry is the first entry of an array
591 * terminated by zero length name.
593 struct list_head cfts;
595 /* base cftypes, automatically registered with subsys itself */
596 struct cftype *base_cftypes;
599 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
600 #include <linux/cgroup_subsys.h>
604 * css_parent - find the parent css
605 * @css: the target cgroup_subsys_state
607 * Return the parent css of @css. This function is guaranteed to return
608 * non-NULL parent as long as @css isn't the root.
611 struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css)
617 * task_css_set_check - obtain a task's css_set with extra access conditions
618 * @task: the task to obtain css_set for
619 * @__c: extra condition expression to be passed to rcu_dereference_check()
621 * A task's css_set is RCU protected, initialized and exited while holding
622 * task_lock(), and can only be modified while holding both cgroup_mutex
623 * and task_lock() while the task is alive. This macro verifies that the
624 * caller is inside proper critical section and returns @task's css_set.
626 * The caller can also specify additional allowed conditions via @__c, such
627 * as locks used during the cgroup_subsys::attach() methods.
629 #ifdef CONFIG_PROVE_RCU
630 extern struct mutex cgroup_mutex;
631 #define task_css_set_check(task, __c) \
632 rcu_dereference_check((task)->cgroups, \
633 lockdep_is_held(&(task)->alloc_lock) || \
634 lockdep_is_held(&cgroup_mutex) || (__c))
636 #define task_css_set_check(task, __c) \
637 rcu_dereference((task)->cgroups)
641 * task_css_check - obtain css for (task, subsys) w/ extra access conds
642 * @task: the target task
643 * @subsys_id: the target subsystem ID
644 * @__c: extra condition expression to be passed to rcu_dereference_check()
646 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
647 * synchronization rules are the same as task_css_set_check().
649 #define task_css_check(task, subsys_id, __c) \
650 task_css_set_check((task), (__c))->subsys[(subsys_id)]
653 * task_css_set - obtain a task's css_set
654 * @task: the task to obtain css_set for
656 * See task_css_set_check().
658 static inline struct css_set *task_css_set(struct task_struct *task)
660 return task_css_set_check(task, false);
664 * task_css - obtain css for (task, subsys)
665 * @task: the target task
666 * @subsys_id: the target subsystem ID
668 * See task_css_check().
670 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
673 return task_css_check(task, subsys_id, false);
676 static inline struct cgroup *task_cgroup(struct task_struct *task,
679 return task_css(task, subsys_id)->cgroup;
682 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
683 struct cgroup_subsys_state *parent);
685 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
688 * css_for_each_child - iterate through children of a css
689 * @pos: the css * to use as the loop cursor
690 * @parent: css whose children to walk
692 * Walk @parent's children. Must be called under rcu_read_lock(). A child
693 * css which hasn't finished ->css_online() or already has finished
694 * ->css_offline() may show up during traversal and it's each subsystem's
695 * responsibility to verify that each @pos is alive.
697 * If a subsystem synchronizes against the parent in its ->css_online() and
698 * before starting iterating, a css which finished ->css_online() is
699 * guaranteed to be visible in the future iterations.
701 * It is allowed to temporarily drop RCU read lock during iteration. The
702 * caller is responsible for ensuring that @pos remains accessible until
703 * the start of the next iteration by, for example, bumping the css refcnt.
705 #define css_for_each_child(pos, parent) \
706 for ((pos) = css_next_child(NULL, (parent)); (pos); \
707 (pos) = css_next_child((pos), (parent)))
709 struct cgroup_subsys_state *
710 css_next_descendant_pre(struct cgroup_subsys_state *pos,
711 struct cgroup_subsys_state *css);
713 struct cgroup_subsys_state *
714 css_rightmost_descendant(struct cgroup_subsys_state *pos);
717 * css_for_each_descendant_pre - pre-order walk of a css's descendants
718 * @pos: the css * to use as the loop cursor
719 * @root: css whose descendants to walk
721 * Walk @root's descendants. @root is included in the iteration and the
722 * first node to be visited. Must be called under rcu_read_lock(). A
723 * descendant css which hasn't finished ->css_online() or already has
724 * finished ->css_offline() may show up during traversal and it's each
725 * subsystem's responsibility to verify that each @pos is alive.
727 * If a subsystem synchronizes against the parent in its ->css_online() and
728 * before starting iterating, and synchronizes against @pos on each
729 * iteration, any descendant css which finished ->css_online() is
730 * guaranteed to be visible in the future iterations.
732 * In other words, the following guarantees that a descendant can't escape
733 * state updates of its ancestors.
737 * Lock @css's parent and @css;
738 * Inherit state from the parent;
742 * my_update_state(@css)
744 * css_for_each_descendant_pre(@pos, @css) {
747 * Update @css's state;
749 * Verify @pos is alive and inherit state from its parent;
754 * As long as the inheriting step, including checking the parent state, is
755 * enclosed inside @pos locking, double-locking the parent isn't necessary
756 * while inheriting. The state update to the parent is guaranteed to be
757 * visible by walking order and, as long as inheriting operations to the
758 * same @pos are atomic to each other, multiple updates racing each other
759 * still result in the correct state. It's guaranateed that at least one
760 * inheritance happens for any css after the latest update to its parent.
762 * If checking parent's state requires locking the parent, each inheriting
763 * iteration should lock and unlock both @pos->parent and @pos.
765 * Alternatively, a subsystem may choose to use a single global lock to
766 * synchronize ->css_online() and ->css_offline() against tree-walking
769 * It is allowed to temporarily drop RCU read lock during iteration. The
770 * caller is responsible for ensuring that @pos remains accessible until
771 * the start of the next iteration by, for example, bumping the css refcnt.
773 #define css_for_each_descendant_pre(pos, css) \
774 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \
775 (pos) = css_next_descendant_pre((pos), (css)))
777 struct cgroup_subsys_state *
778 css_next_descendant_post(struct cgroup_subsys_state *pos,
779 struct cgroup_subsys_state *css);
782 * css_for_each_descendant_post - post-order walk of a css's descendants
783 * @pos: the css * to use as the loop cursor
784 * @css: css whose descendants to walk
786 * Similar to css_for_each_descendant_pre() but performs post-order
787 * traversal instead. @root is included in the iteration and the last
788 * node to be visited. Note that the walk visibility guarantee described
789 * in pre-order walk doesn't apply the same to post-order walks.
791 #define css_for_each_descendant_post(pos, css) \
792 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
793 (pos) = css_next_descendant_post((pos), (css)))
795 /* A css_task_iter should be treated as an opaque object */
796 struct css_task_iter {
797 struct cgroup_subsys_state *origin_css;
798 struct list_head *cset_link;
799 struct list_head *task;
802 void css_task_iter_start(struct cgroup_subsys_state *css,
803 struct css_task_iter *it);
804 struct task_struct *css_task_iter_next(struct css_task_iter *it);
805 void css_task_iter_end(struct css_task_iter *it);
807 int css_scan_tasks(struct cgroup_subsys_state *css,
808 bool (*test)(struct task_struct *, void *),
809 void (*process)(struct task_struct *, void *),
810 void *data, struct ptr_heap *heap);
812 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
813 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
815 struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry,
816 struct cgroup_subsys *ss);
818 #else /* !CONFIG_CGROUPS */
820 static inline int cgroup_init_early(void) { return 0; }
821 static inline int cgroup_init(void) { return 0; }
822 static inline void cgroup_fork(struct task_struct *p) {}
823 static inline void cgroup_post_fork(struct task_struct *p) {}
824 static inline void cgroup_exit(struct task_struct *p, int callbacks) {}
826 static inline int cgroupstats_build(struct cgroupstats *stats,
827 struct dentry *dentry)
832 /* No cgroups - nothing to do */
833 static inline int cgroup_attach_task_all(struct task_struct *from,
834 struct task_struct *t)
839 #endif /* !CONFIG_CGROUPS */
841 #endif /* _LINUX_CGROUP_H */