#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/cgroupstats.h>#include <linux/prio_heap.h>#include <linux/rwsem.h>#include <linux/idr.h> #ifdef CONFIG_CGROUPS struct cgroupfs_root;struct cgroup_subsys;struct inode;struct cgroup;struct css_id; extern int cgroup_init_early(void);extern int cgroup_init(void);extern void cgroup_lock(void);extern int cgroup_lock_is_held(void);extern bool cgroup_lock_live_group(struct cgroup *cgrp);extern void cgroup_unlock(void);extern void cgroup_fork(struct task_struct *p);extern void cgroup_fork_callbacks(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 const struct file_operations proc_cgroup_operations; /* Define the enumeration of all builtin cgroup subsystems */#define SUBSYS(_x) _x ## _subsys_id,enum cgroup_subsys_id {#include <linux/cgroup_subsys.h>	CGROUP_BUILTIN_SUBSYS_COUNT};#undef SUBSYS/* * This define indicates the maximum number of subsystems that can be loaded * at once. We limit to this many since cgroupfs_root has subsys_bits to keep * track of all of them. */#define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long)) /* 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 and css_put().	 */ 	atomic_t refcnt; 	unsigned long flags;	/* ID for this css, if possible */	struct css_id __rcu *id;}; /* bits in struct cgroup_subsys_state flags field */enum {	CSS_ROOT, /* This CSS is the root of the subsystem */	CSS_REMOVED, /* This CSS is dead */}; /* 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 (!test_bit(CSS_ROOT, &css->flags))		__css_get(css, 1);} static inline bool css_is_removed(struct cgroup_subsys_state *css){	return test_bit(CSS_REMOVED, &css->flags);} /* * 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. */ static inline bool css_tryget(struct cgroup_subsys_state *css){	if (test_bit(CSS_ROOT, &css->flags))		return true;	while (!atomic_inc_not_zero(&css->refcnt)) {		if (test_bit(CSS_REMOVED, &css->flags))			return false;		cpu_relax();	}	return true;} /* * 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, int count);static inline void css_put(struct cgroup_subsys_state *css){	if (!test_bit(CSS_ROOT, &css->flags))		__css_put(css, 1);} /* 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,	/*	 * A thread in rmdir() is wating for this cgroup.	 */	CGRP_WAIT_ON_RMDIR,	/*	 * Clone cgroup values when creating a new child cgroup	 */	CGRP_CLONE_CHILDREN,}; /* which pidlist file are we talking about? */enum cgroup_filetype {	CGROUP_FILE_PROCS,	CGROUP_FILE_TASKS,}; /* * A pidlist is a list of pids that virtually represents the contents of one * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists, * a pair (one each for procs, tasks) for each pid namespace that's relevant * to the cgroup. */struct cgroup_pidlist {	/*	 * used to find which pidlist is wanted. doesn't change as long as	 * this particular list stays in the list.	 */	struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;	/* array of xids */	pid_t *list;	/* how many elements the above list has */	int length;	/* how many files are using the current array */	int use_count;	/* each of these stored in a list by its cgroup */	struct list_head links;	/* pointer to the cgroup we belong to, for list removal purposes */	struct cgroup *owner;	/* protects the other fields */	struct rw_semaphore mutex;}; 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; 	/*	 * 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 cgroup *parent;		/* my parent */	struct dentry __rcu *dentry;	/* cgroup fs entry, RCU protected */ 	/* Private pointers for each registered subsystem */	struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; 	struct cgroupfs_root *root;	struct cgroup *top_cgroup; 	/*	 * List of cg_cgroup_links pointing at css_sets with	 * tasks in this cgroup. Protected by css_set_lock	 */	struct list_head css_sets; 	/*	 * 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; 	/* List of events which userspace want to receive */	struct list_head event_list;	spinlock_t event_list_lock;}; /* * 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 cg_cgroup_link objects on link chains from	 * cgroups referenced from this css_set. Protected by	 * css_set_lock	 */	struct list_head cg_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 */ #define MAX_CFTYPE_NAME 64struct cftype {	/*	 * By convention, the name should begin with the name of the	 * subsystem, followed by a period	 */	char name[MAX_CFTYPE_NAME];	int private;	/*	 * If not 0, file mode is set to this value, otherwise it will	 * be figured out automatically	 */	mode_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; 	int (*open)(struct inode *inode, struct file *file);	ssize_t (*read)(struct cgroup *cgrp, 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 *cgrp, struct cftype *cft);	/*	 * read_s64() is a signed version of read_u64()	 */	s64 (*read_s64)(struct cgroup *cgrp, 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 *cont, 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 *cont, struct cftype *cft,			       struct seq_file *m); 	ssize_t (*write)(struct cgroup *cgrp, 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 *cgrp, struct cftype *cft, u64 val);	/*	 * write_s64() is a signed version of write_u64()	 */	int (*write_s64)(struct cgroup *cgrp, 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 *cgrp, struct cftype *cft,			    const char *buffer);	/*	 * trigger() callback can be used to get some kick from the	 * userspace, when the actual string written is not important	 * at all. The private field can be used to determine the	 * kick type for multiplexing.	 */	int (*trigger)(struct cgroup *cgrp, unsigned int event); 	int (*release)(struct inode *inode, struct file *file); 	/*	 * register_event() callback will be used to add new userspace	 * waiter for changes related to the cftype. Implement it if	 * you want to provide this functionality. Use eventfd_signal()	 * on eventfd to send notification to userspace.	 */	int (*register_event)(struct cgroup *cgrp, struct cftype *cft,			struct eventfd_ctx *eventfd, const char *args);	/*	 * unregister_event() callback will be called when userspace	 * closes the eventfd or on cgroup removing.	 * This callback must be implemented, if you want provide	 * notification functionality.	 */	void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft,			struct eventfd_ctx *eventfd);}; struct cgroup_scanner {	struct cgroup *cg;	int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan);	void (*process_task)(struct task_struct *p,			struct cgroup_scanner *scan);	struct ptr_heap *heap;	void *data;}; /* * Add a new file to the given cgroup directory. Should only be * called by subsystems from within a populate() method */int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,		       const struct cftype *cft); /* * Add a set of new files to the given cgroup directory. Should * only be called by subsystems from within a populate() method */int cgroup_add_files(struct cgroup *cgrp,			struct cgroup_subsys *subsys,			const struct cftype cft[],			int count); int cgroup_is_removed(const struct cgroup *cgrp); int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); int cgroup_task_count(const struct cgroup *cgrp); /* Return true if cgrp is a descendant of the task's cgroup */int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); /* * When the subsys has to access css and may add permanent refcnt to css, * it should take care of racy conditions with rmdir(). Following set of * functions, is for stop/restart rmdir if necessary. * Because these will call css_get/put, "css" should be alive css. * *  cgroup_exclude_rmdir(); *  ...do some jobs which may access arbitrary empty cgroup *  cgroup_release_and_wakeup_rmdir(); * *  When someone removes a cgroup while cgroup_exclude_rmdir() holds it, *  it sleeps and cgroup_release_and_wakeup_rmdir() will wake him up. */ void cgroup_exclude_rmdir(struct cgroup_subsys_state *css);void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css); /* * Control Group subsystem type. * See Documentation/cgroups/cgroups.txt for details */ struct cgroup_subsys {	struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,						  struct cgroup *cgrp);	int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);	void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);	int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,			  struct task_struct *tsk);	int (*can_attach_task)(struct cgroup *cgrp, struct task_struct *tsk);	void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,			      struct task_struct *tsk);	void (*pre_attach)(struct cgroup *cgrp);	void (*attach_task)(struct cgroup *cgrp, struct task_struct *tsk);	void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,		       struct cgroup *old_cgrp, struct task_struct *tsk);	void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);	void (*exit)(struct cgroup_subsys *ss, struct cgroup *cgrp,			struct cgroup *old_cgrp, struct task_struct *task);	int (*populate)(struct cgroup_subsys *ss,			struct cgroup *cgrp);	void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp);	void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); 	int subsys_id;	int active;	int disabled;	int early_init;	/*	 * True if this subsys uses ID. ID is not available before cgroup_init()	 * (not available in early_init time.)	 */	bool use_id;#define MAX_CGROUP_TYPE_NAMELEN 32	const char *name; 	/*	 * Protects sibling/children links of cgroups in this	 * hierarchy, plus protects which hierarchy (or none) the

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