#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>#include <linux/percpu-refcount.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 css is attached to */	struct cgroup *cgroup; 	/* the cgroup subsystem that this css is attached to */	struct cgroup_subsys *ss; 	/* reference count - access via css_[try]get() and css_put() */	struct percpu_ref refcnt; 	/* the parent css */	struct cgroup_subsys_state *parent; 	unsigned long flags;	/* ID for this css, if possible */	struct css_id __rcu *id; 	/* percpu_ref killing and RCU release */	struct rcu_head rcu_head;	struct work_struct destroy_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() */}; /** * css_get - obtain a reference on the specified css * @css: target css * * The caller must already have a reference. */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))		percpu_ref_get(&css->refcnt);} /** * css_tryget - try to obtain a reference on the specified css * @css: target css * * Obtain a reference on @css if it's alive.  The caller naturally needs to * ensure that @css is accessible but doesn't have to be holding a * reference on it - IOW, RCU protected access is good enough for this * function.  Returns %true if a reference count was successfully obtained; * %false otherwise. */static inline bool css_tryget(struct cgroup_subsys_state *css){	if (css->flags & CSS_ROOT)		return true;	return percpu_ref_tryget(&css->refcnt);} /** * css_put - put a css reference * @css: target css * * Put a reference obtained via css_get() and css_tryget(). */static inline void css_put(struct cgroup_subsys_state *css){	if (!(css->flags & CSS_ROOT))		percpu_ref_put(&css->refcnt);} /* bits in struct cgroup flags field */enum {	/* Control Group is dead */	CGRP_DEAD,	/*	 * 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 */ 	/*	 * idr allocated in-hierarchy ID.	 *	 * The ID of the root cgroup is always 0, and a new cgroup	 * will be assigned with a smallest available ID.	 */	int id; 	/* the number of attached css's */	int nr_css; 	/*	 * 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 */ 	/*	 * Monotonically increasing unique serial number which defines a	 * uniform order among all cgroups.  It's guaranteed that all	 * ->children lists are in the ascending order of ->serial_nr.	 * It's used to allow interrupting and resuming iterations.	 */	u64 serial_nr; 	/*	 * 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 __rcu *subsys[CGROUP_SUBSYS_COUNT]; 	struct cgroupfs_root *root; 	/*	 * List of cgrp_cset_links pointing at css_sets with tasks in this	 * cgroup.  Protected by css_set_lock.	 */	struct list_head cset_links; 	/*	 * 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; 	/* dummy css with NULL ->ss, points back to this cgroup */	struct cgroup_subsys_state dummy_css; 	/* For css percpu_ref killing and RCU-protected deletion */	struct rcu_head rcu_head;	struct work_struct destroy_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.	 *	 * - rename(2) is disallowed.	 *	 * - "tasks" is removed.  Everything should be at process	 *   granularity.  Use "cgroup.procs" instead.	 *	 * - "release_agent" and "notify_on_release" are removed.	 *   Replacement notification mechanism will be implemented.	 *	 * - cpuset: tasks will be kept in empty cpusets when hotplug happens	 *   and take masks of ancestors with non-empty cpus/mems, instead of	 *   being moved to an ancestor.	 *	 * - cpuset: a task can be moved into an empty cpuset, and again it	 *   takes masks of ancestors.	 *	 * - memcg: use_hierarchy is on by default and the cgroup file for	 *   the flag is not created.	 *	 * - blkcg: blk-throttle becomes properly hierarchical.	 */	CGRP_ROOT_SANE_BEHAVIOR	= (1 << 0), 	CGRP_ROOT_NOPREFIX	= (1 << 1), /* mounted subsystems have no named prefix */	CGRP_ROOT_XATTR		= (1 << 2), /* supports extended attributes */ 	/* mount options live below bit 16 */	CGRP_ROOT_OPTION_MASK	= (1 << 16) - 1, 	CGRP_ROOT_SUBSYS_BOUND	= (1 << 16), /* subsystems finished binding */}; /* * A cgroupfs_root represents the root of a cgroup hierarchy, and may be * associated with a superblock to form an active hierarchy.  This is * internal to cgroup core.  Don't access directly from controllers. */struct cgroupfs_root {	struct super_block *sb; 	/* The bitmask of subsystems attached to this hierarchy */	unsigned long subsys_mask; 	/* Unique id for this hierarchy. */	int hierarchy_id; 	/* A list running through the attached subsystems */	struct list_head subsys_list; 	/* The root cgroup for this hierarchy */	struct cgroup top_cgroup; 	/* Tracks how many cgroups are currently defined in hierarchy.*/	int number_of_cgroups; 	/* A list running through the active hierarchies */	struct list_head root_list; 	/* Hierarchy-specific flags */	unsigned long flags; 	/* IDs for cgroups in this hierarchy */	struct idr cgroup_idr; 	/* The path to use for release notifications. */	char release_agent_path[PATH_MAX]; 	/* The name for this hierarchy - may be empty */	char name[MAX_CGROUP_ROOT_NAMELEN];}; /* * A css_set is a structure holding pointers to a set of * cgroup_subsys_state objects. This saves space in the task struct * object and speeds up fork()/exit(), since a single inc/dec and a * list_add()/del() can bump the reference count on the entire cgroup * set for a task. */ struct css_set { 	/* Reference count */	atomic_t refcount; 	/*	 * List running through all cgroup groups in the same hash	 * slot. Protected by css_set_lock	 */	struct hlist_node hlist; 	/*	 * List running through all tasks using this cgroup	 * group. Protected by css_set_lock	 */	struct list_head tasks; 	/*	 * List of cgrp_cset_links pointing at cgroups referenced from this	 * css_set.  Protected by css_set_lock.	 */	struct list_head cgrp_links; 	/*	 * Set of subsystem states, one for each subsystem. This array	 * is immutable after creation apart from the init_css_set	 * during subsystem registration (at boot time) and modular subsystem	 * loading/unloading.	 */	struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; 	/* For RCU-protected deletion */	struct rcu_head rcu_head;}; /* * cgroup_map_cb is an abstract callback API for reporting map-valued * control files */ struct cgroup_map_cb {	int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value);	void *state;}; /* * struct cftype: handler definitions for cgroup control files * * When reading/writing to a file: *	- the cgroup to use is file->f_dentry->d_parent->d_fsdata *	- the 'cftype' of the file is file->f_dentry->d_fsdata */ /* cftype->flags */enum {	CFTYPE_ONLY_ON_ROOT	= (1 << 0),	/* only create on root cgrp */	CFTYPE_NOT_ON_ROOT	= (1 << 1),	/* don't create on root cgrp */	CFTYPE_INSANE		= (1 << 2),	/* don't create if sane_behavior */	CFTYPE_NO_PREFIX	= (1 << 3),	/* (DON'T USE FOR NEW FILES) no subsys prefix */}; #define MAX_CFTYPE_NAME		64 struct cftype {	/*	 * By convention, the name should begin with the name of the	 * subsystem, followed by a period.  Zero length string indicates	 * end of cftype array.	 */	char name[MAX_CFTYPE_NAME];	int private;	/*	 * If not 0, file mode is set to this value, otherwise it will	 * be figured out automatically	 */	umode_t mode; 	/*	 * If non-zero, defines the maximum length of string that can	 * be passed to write_string; defaults to 64	 */	size_t max_write_len; 	/* CFTYPE_* flags */	unsigned int flags; 	/*	 * The subsys this file belongs to.  Initialized automatically	 * during registration.  NULL for cgroup core files.	 */	struct cgroup_subsys *ss; 	int (*open)(struct inode *inode, struct file *file);	ssize_t (*read)(struct cgroup_subsys_state *css, struct cftype *cft,			struct file *file,			char __user *buf, size_t nbytes, loff_t *ppos);	/*	 * read_u64() is a shortcut for the common case of returning a	 * single integer. Use it in place of read()	 */	u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft);	/*	 * read_s64() is a signed version of read_u64()	 */	s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft);	/*	 * read_map() is used for defining a map of key/value	 * pairs. It should call cb->fill(cb, key, value) for each	 * entry. The key/value pairs (and their ordering) should not	 * change between reboots.	 */	int (*read_map)(struct cgroup_subsys_state *css, struct cftype *cft,			struct cgroup_map_cb *cb);	/*	 * read_seq_string() is used for outputting a simple sequence	 * using seqfile.	 */	int (*read_seq_string)(struct cgroup_subsys_state *css,			       struct cftype *cft, struct seq_file *m); 	ssize_t (*write)(struct cgroup_subsys_state *css, struct cftype *cft,			 struct file *file,			 const char __user *buf, size_t nbytes, loff_t *ppos); 	/*	 * write_u64() is a shortcut for the common case of accepting	 * a single integer (as parsed by simple_strtoull) from	 * userspace. Use in place of write(); return 0 or error.	 */	int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft,			 u64 val);	/*	 * write_s64() is a signed version of write_u64()	 */	int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft,			 s64 val); 	/*	 * write_string() is passed a nul-terminated kernelspace	 * buffer of maximum length determined by max_write_len.	 * Returns 0 or -ve error code.	 */	int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft,			    const char *buffer);	/*

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