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#ifndef _LINUX_CGROUP_H
#define _LINUX_CGROUP_H
/*
* cgroup interface
*
* Copyright (C) 2003 BULL SA
* Copyright (C) 2004-2006 Silicon Graphics, Inc.
*
*/
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/cgroupstats.h>
#include <linux/prio_heap.h>
#include <linux/rwsem.h>
#include <linux/idr.h>
#include <linux/workqueue.h>
#include <linux/xattr.h>
#include <linux/fs.h>
#ifdef CONFIG_CGROUPS
struct cgroupfs_root;
struct cgroup_subsys;
struct inode;
struct cgroup;
struct css_id;
struct eventfd_ctx;
extern int cgroup_init_early(void);
extern int cgroup_init(void);
extern void cgroup_fork(struct task_struct *p);
extern void cgroup_post_fork(struct task_struct *p);
extern void cgroup_exit(struct task_struct *p, int run_callbacks);
extern int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry);
extern int cgroup_load_subsys(struct cgroup_subsys *ss);
extern void cgroup_unload_subsys(struct cgroup_subsys *ss);
extern int proc_cgroup_show(struct seq_file *, void *);
/*
* Define the enumeration of all cgroup subsystems.
*
* We define ids for builtin subsystems and then modular ones.
*/
#define SUBSYS(_x) _x ## _subsys_id,
enum cgroup_subsys_id {
#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
#include <linux/cgroup_subsys.h>
#undef IS_SUBSYS_ENABLED
CGROUP_BUILTIN_SUBSYS_COUNT,
__CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1,
#define IS_SUBSYS_ENABLED(option) IS_MODULE(option)
#include <linux/cgroup_subsys.h>
#undef IS_SUBSYS_ENABLED
CGROUP_SUBSYS_COUNT,
};
#undef SUBSYS
/* Per-subsystem/per-cgroup state maintained by the system. */
struct cgroup_subsys_state {
/*
* The cgroup that this subsystem is attached to. Useful
* for subsystems that want to know about the cgroup
* hierarchy structure
*/
struct cgroup *cgroup;
/*
* State maintained by the cgroup system to allow subsystems
* to be "busy". Should be accessed via css_get(),
* css_tryget() and css_put().
*/
atomic_t refcnt;
unsigned long flags;
/* ID for this css, if possible */
struct css_id __rcu *id;
/* Used to put @cgroup->dentry on the last css_put() */
struct work_struct dput_work;
};
/* bits in struct cgroup_subsys_state flags field */
enum {
CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */
CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */
};
/* Caller must verify that the css is not for root cgroup */
static inline void __css_get(struct cgroup_subsys_state *css, int count)
{
atomic_add(count, &css->refcnt);
}
/*
* Call css_get() to hold a reference on the css; it can be used
* for a reference obtained via:
* - an existing ref-counted reference to the css
* - task->cgroups for a locked task
*/
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
if (!(css->flags & CSS_ROOT))
__css_get(css, 1);
}
/*
* Call css_tryget() to take a reference on a css if your existing
* (known-valid) reference isn't already ref-counted. Returns false if
* the css has been destroyed.
*/
extern bool __css_tryget(struct cgroup_subsys_state *css);
static inline bool css_tryget(struct cgroup_subsys_state *css)
{
if (css->flags & CSS_ROOT)
return true;
return __css_tryget(css);
}
/*
* css_put() should be called to release a reference taken by
* css_get() or css_tryget()
*/
extern void __css_put(struct cgroup_subsys_state *css);
static inline void css_put(struct cgroup_subsys_state *css)
{
if (!(css->flags & CSS_ROOT))
__css_put(css);
}
/* bits in struct cgroup flags field */
enum {
/* Control Group is dead */
CGRP_REMOVED,
/*
* Control Group has previously had a child cgroup or a task,
* but no longer (only if CGRP_NOTIFY_ON_RELEASE is set)
*/
CGRP_RELEASABLE,
/* Control Group requires release notifications to userspace */
CGRP_NOTIFY_ON_RELEASE,
/*
* Clone the parent's configuration when creating a new child
* cpuset cgroup. For historical reasons, this option can be
* specified at mount time and thus is implemented here.
*/
CGRP_CPUSET_CLONE_CHILDREN,
/* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */
CGRP_SANE_BEHAVIOR,
};
struct cgroup_name {
struct rcu_head rcu_head;
char name[];
};
struct cgroup {
unsigned long flags; /* "unsigned long" so bitops work */
/*
* count users of this cgroup. >0 means busy, but doesn't
* necessarily indicate the number of tasks in the cgroup
*/
atomic_t count;
int id; /* ida allocated in-hierarchy ID */
/*
* We link our 'sibling' struct into our parent's 'children'.
* Our children link their 'sibling' into our 'children'.
*/
struct list_head sibling; /* my parent's children */
struct list_head children; /* my children */
struct list_head files; /* my files */
struct cgroup *parent; /* my parent */
struct dentry *dentry; /* cgroup fs entry, RCU protected */
/*
* This is a copy of dentry->d_name, and it's needed because
* we can't use dentry->d_name in cgroup_path().
*
* You must acquire rcu_read_lock() to access cgrp->name, and
* the only place that can change it is rename(), which is
* protected by parent dir's i_mutex.
*
* Normally you should use cgroup_name() wrapper rather than
* access it directly.
*/
struct cgroup_name __rcu *name;
/* Private pointers for each registered subsystem */
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
struct cgroupfs_root *root;
/*
* List of cg_cgroup_links pointing at css_sets with
* tasks in this cgroup. Protected by css_set_lock
*/
struct list_head css_sets;
struct list_head allcg_node; /* cgroupfs_root->allcg_list */
struct list_head cft_q_node; /* used during cftype add/rm */
/*
* Linked list running through all cgroups that can
* potentially be reaped by the release agent. Protected by
* release_list_lock
*/
struct list_head release_list;
/*
* list of pidlists, up to two for each namespace (one for procs, one
* for tasks); created on demand.
*/
struct list_head pidlists;
struct mutex pidlist_mutex;
/* For RCU-protected deletion */
struct rcu_head rcu_head;
struct work_struct free_work;
/* List of events which userspace want to receive */
struct list_head event_list;
spinlock_t event_list_lock;
/* directory xattrs */
struct simple_xattrs xattrs;
};
#define MAX_CGROUP_ROOT_NAMELEN 64
/* cgroupfs_root->flags */
enum {
/*
* Unfortunately, cgroup core and various controllers are riddled
* with idiosyncrasies and pointless options. The following flag,
* when set, will force sane behavior - some options are forced on,
* others are disallowed, and some controllers will change their
* hierarchical or other behaviors.
*
* The set of behaviors affected by this flag are still being
* determined and developed and the mount option for this flag is
* prefixed with __DEVEL__. The prefix will be dropped once we
* reach the point where all behaviors are compatible with the
* planned unified hierarchy, which will automatically turn on this
* flag.
*
* The followings are the behaviors currently affected this flag.
*
* - Mount options "noprefix" and "clone_children" are disallowed.
* Also, cgroupfs file cgroup.clone_children is not created.
*
* - When mounting an existing superblock, mount options should
* match.
*
* - Remount is disallowed.
*
* - memcg: use_hierarchy is on by default and the cgroup file for
* the flag is not created.
*
* The followings are planned changes.
*
* - release_agent will be disallowed once replacement notification
* mechanism is implemented.
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