[mirror_ubuntu-artful-kernel.git] / kernel / cgroup / cgroup-internal.h

#ifndef __CGROUP_INTERNAL_H
#define __CGROUP_INTERNAL_H

#include <linux/cgroup.h>
#include <linux/kernfs.h>
#include <linux/workqueue.h>
#include <linux/list.h>
#include <linux/refcount.h>

/*
 * A cgroup can be associated with multiple css_sets as different tasks may
 * belong to different cgroups on different hierarchies.  In the other
 * direction, a css_set is naturally associated with multiple cgroups.
 * This M:N relationship is represented by the following link structure
 * which exists for each association and allows traversing the associations
 * from both sides.
 */
struct cgrp_cset_link {
	/* the cgroup and css_set this link associates */
	struct cgroup		*cgrp;
	struct css_set		*cset;

	/* list of cgrp_cset_links anchored at cgrp->cset_links */
	struct list_head	cset_link;

	/* list of cgrp_cset_links anchored at css_set->cgrp_links */
	struct list_head	cgrp_link;
};

/* used to track tasks and csets during migration */
struct cgroup_taskset {
	/* the src and dst cset list running through cset->mg_node */
	struct list_head	src_csets;
	struct list_head	dst_csets;

	/* the subsys currently being processed */
	int			ssid;

	/*
	 * Fields for cgroup_taskset_*() iteration.
	 *
	 * Before migration is committed, the target migration tasks are on
	 * ->mg_tasks of the csets on ->src_csets.  After, on ->mg_tasks of
	 * the csets on ->dst_csets.  ->csets point to either ->src_csets
	 * or ->dst_csets depending on whether migration is committed.
	 *
	 * ->cur_csets and ->cur_task point to the current task position
	 * during iteration.
	 */
	struct list_head	*csets;
	struct css_set		*cur_cset;
	struct task_struct	*cur_task;
};

/* migration context also tracks preloading */
struct cgroup_mgctx {
	/*
	 * Preloaded source and destination csets.  Used to guarantee
	 * atomic success or failure on actual migration.
	 */
	struct list_head	preloaded_src_csets;
	struct list_head	preloaded_dst_csets;

	/* tasks and csets to migrate */
	struct cgroup_taskset	tset;

	/* subsystems affected by migration */
	u16			ss_mask;
};

#define CGROUP_TASKSET_INIT(tset)						\
{										\
	.src_csets		= LIST_HEAD_INIT(tset.src_csets),		\
	.dst_csets		= LIST_HEAD_INIT(tset.dst_csets),		\
	.csets			= &tset.src_csets,				\
}

#define CGROUP_MGCTX_INIT(name)							\
{										\
	LIST_HEAD_INIT(name.preloaded_src_csets),				\
	LIST_HEAD_INIT(name.preloaded_dst_csets),				\
	CGROUP_TASKSET_INIT(name.tset),						\
}

#define DEFINE_CGROUP_MGCTX(name)						\
	struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)

struct cgroup_sb_opts {
	u16 subsys_mask;
	unsigned int flags;
	char *release_agent;
	bool cpuset_clone_children;
	char *name;
	/* User explicitly requested empty subsystem */
	bool none;
};

extern struct mutex cgroup_mutex;
extern spinlock_t css_set_lock;
extern struct cgroup_subsys *cgroup_subsys[];
extern struct list_head cgroup_roots;
extern struct file_system_type cgroup_fs_type;

/* iterate across the hierarchies */
#define for_each_root(root)						\
	list_for_each_entry((root), &cgroup_roots, root_list)

/**
 * for_each_subsys - iterate all enabled cgroup subsystems
 * @ss: the iteration cursor
 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
 */
#define for_each_subsys(ss, ssid)					\
	for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT &&		\
	     (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)

static inline bool cgroup_is_dead(const struct cgroup *cgrp)
{
	return !(cgrp->self.flags & CSS_ONLINE);
}

static inline bool notify_on_release(const struct cgroup *cgrp)
{
	return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
}

void put_css_set_locked(struct css_set *cset);

static inline void put_css_set(struct css_set *cset)
{
	unsigned long flags;

	/*
	 * Ensure that the refcount doesn't hit zero while any readers
	 * can see it. Similar to atomic_dec_and_lock(), but for an
	 * rwlock
	 */
	if (refcount_dec_not_one(&cset->refcount))
		return;

	spin_lock_irqsave(&css_set_lock, flags);
	put_css_set_locked(cset);
	spin_unlock_irqrestore(&css_set_lock, flags);
}

/*
 * refcounted get/put for css_set objects
 */
static inline void get_css_set(struct css_set *cset)
{
	refcount_inc(&cset->refcount);
}

bool cgroup_ssid_enabled(int ssid);
bool cgroup_on_dfl(const struct cgroup *cgrp);

struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
struct cgroup *task_cgroup_from_root(struct task_struct *task,
				     struct cgroup_root *root);
struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
void cgroup_kn_unlock(struct kernfs_node *kn);
int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
			  struct cgroup_namespace *ns);

void cgroup_free_root(struct cgroup_root *root);
void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
			       struct cgroup_root *root, unsigned long magic,
			       struct cgroup_namespace *ns);

bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
			    struct cgroup_mgctx *mgctx);
int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
int cgroup_migrate(struct task_struct *leader, bool threadgroup,
		   struct cgroup_mgctx *mgctx);

int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
		       bool threadgroup);
ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
			     size_t nbytes, loff_t off, bool threadgroup);
ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
			   loff_t off);

void cgroup_lock_and_drain_offline(struct cgroup *cgrp);

int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
int cgroup_rmdir(struct kernfs_node *kn);
int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
		     struct kernfs_root *kf_root);

int cgroup_task_count(const struct cgroup *cgrp);

/*
 * namespace.c
 */
extern const struct proc_ns_operations cgroupns_operations;

/*
 * cgroup-v1.c
 */
extern struct cftype cgroup1_base_files[];
extern const struct file_operations proc_cgroupstats_operations;
extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;

bool cgroup1_ssid_disabled(int ssid);
void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
void cgroup1_release_agent(struct work_struct *work);
void cgroup1_check_for_release(struct cgroup *cgrp);
struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
			     void *data, unsigned long magic,
			     struct cgroup_namespace *ns);

#endif /* __CGROUP_INTERNAL_H */
Commit	Line	Data
0a268dbd TH	1	#ifndef __CGROUP_INTERNAL_H
	2	#define __CGROUP_INTERNAL_H
	3
	4	#include <linux/cgroup.h>
	5	#include <linux/kernfs.h>
	6	#include <linux/workqueue.h>
	7	#include <linux/list.h>
4b9502e6	8	#include <linux/refcount.h>
0a268dbd TH	9
	10	/*
	11	* A cgroup can be associated with multiple css_sets as different tasks may
	12	* belong to different cgroups on different hierarchies. In the other
	13	* direction, a css_set is naturally associated with multiple cgroups.
	14	* This M:N relationship is represented by the following link structure
	15	* which exists for each association and allows traversing the associations
	16	* from both sides.
	17	*/
	18	struct cgrp_cset_link {
	19	/* the cgroup and css_set this link associates */
	20	struct cgroup *cgrp;
	21	struct css_set *cset;
	22
	23	/* list of cgrp_cset_links anchored at cgrp->cset_links */
	24	struct list_head cset_link;
	25
	26	/* list of cgrp_cset_links anchored at css_set->cgrp_links */
	27	struct list_head cgrp_link;
	28	};
	29
e595cd70 TH	30	/* used to track tasks and csets during migration */
	31	struct cgroup_taskset {
	32	/* the src and dst cset list running through cset->mg_node */
	33	struct list_head src_csets;
	34	struct list_head dst_csets;
	35
	36	/* the subsys currently being processed */
	37	int ssid;
	38
	39	/*
	40	* Fields for cgroup_taskset_*() iteration.
	41	*
	42	* Before migration is committed, the target migration tasks are on
	43	* ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of
	44	* the csets on ->dst_csets. ->csets point to either ->src_csets
	45	* or ->dst_csets depending on whether migration is committed.
	46	*
	47	* ->cur_csets and ->cur_task point to the current task position
	48	* during iteration.
	49	*/
	50	struct list_head *csets;
	51	struct css_set *cur_cset;
	52	struct task_struct *cur_task;
	53	};
	54
	55	/* migration context also tracks preloading */
	56	struct cgroup_mgctx {
	57	/*
	58	* Preloaded source and destination csets. Used to guarantee
	59	* atomic success or failure on actual migration.
	60	*/
	61	struct list_head preloaded_src_csets;
	62	struct list_head preloaded_dst_csets;
	63
	64	/* tasks and csets to migrate */
	65	struct cgroup_taskset tset;
bfc2cf6f TH	66
	67	/* subsystems affected by migration */
	68	u16 ss_mask;
e595cd70 TH	69	};
	70
	71	#define CGROUP_TASKSET_INIT(tset) \
	72	{ \
	73	.src_csets = LIST_HEAD_INIT(tset.src_csets), \
	74	.dst_csets = LIST_HEAD_INIT(tset.dst_csets), \
	75	.csets = &tset.src_csets, \
	76	}
	77
	78	#define CGROUP_MGCTX_INIT(name) \
	79	{ \
	80	LIST_HEAD_INIT(name.preloaded_src_csets), \
	81	LIST_HEAD_INIT(name.preloaded_dst_csets), \
	82	CGROUP_TASKSET_INIT(name.tset), \
	83	}
	84
	85	#define DEFINE_CGROUP_MGCTX(name) \
	86	struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
	87
1592c9b2 TH	88	struct cgroup_sb_opts {
	89	u16 subsys_mask;
	90	unsigned int flags;
	91	char *release_agent;
	92	bool cpuset_clone_children;
	93	char *name;
	94	/* User explicitly requested empty subsystem */
	95	bool none;
	96	};
	97
0a268dbd TH	98	extern struct mutex cgroup_mutex;
	99	extern spinlock_t css_set_lock;
	100	extern struct cgroup_subsys *cgroup_subsys[];
	101	extern struct list_head cgroup_roots;
	102	extern struct file_system_type cgroup_fs_type;
	103
	104	/* iterate across the hierarchies */
	105	#define for_each_root(root) \
	106	list_for_each_entry((root), &cgroup_roots, root_list)
	107
	108	/**
	109	* for_each_subsys - iterate all enabled cgroup subsystems
	110	* @ss: the iteration cursor
	111	* @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
	112	*/
	113	#define for_each_subsys(ss, ssid) \
	114	for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
	115	(((ss) = cgroup_subsys[ssid]) \|\| true); (ssid)++)
	116
	117	static inline bool cgroup_is_dead(const struct cgroup *cgrp)
	118	{
	119	return !(cgrp->self.flags & CSS_ONLINE);
	120	}
	121
	122	static inline bool notify_on_release(const struct cgroup *cgrp)
	123	{
	124	return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
	125	}
	126
dcfe149b TH	127	void put_css_set_locked(struct css_set *cset);
	128
	129	static inline void put_css_set(struct css_set *cset)
	130	{
	131	unsigned long flags;
	132
	133	/*
	134	* Ensure that the refcount doesn't hit zero while any readers
	135	* can see it. Similar to atomic_dec_and_lock(), but for an
	136	* rwlock
	137	*/
4b9502e6	138	if (refcount_dec_not_one(&cset->refcount))
dcfe149b TH	139	return;
	140
	141	spin_lock_irqsave(&css_set_lock, flags);
	142	put_css_set_locked(cset);
	143	spin_unlock_irqrestore(&css_set_lock, flags);
	144	}
	145
	146	/*
	147	* refcounted get/put for css_set objects
	148	*/
	149	static inline void get_css_set(struct css_set *cset)
	150	{
4b9502e6	151	refcount_inc(&cset->refcount);
dcfe149b TH	152	}
dcfe149b TH	153
0a268dbd TH	154	bool cgroup_ssid_enabled(int ssid);
	155	bool cgroup_on_dfl(const struct cgroup *cgrp);
	156
	157	struct cgroup_root cgroup_root_from_kf(struct kernfs_root kf_root);
	158	struct cgroup task_cgroup_from_root(struct task_struct task,
	159	struct cgroup_root *root);
	160	struct cgroup cgroup_kn_lock_live(struct kernfs_node kn, bool drain_offline);
	161	void cgroup_kn_unlock(struct kernfs_node *kn);
	162	int cgroup_path_ns_locked(struct cgroup cgrp, char buf, size_t buflen,
	163	struct cgroup_namespace *ns);
	164
1592c9b2 TH	165	void cgroup_free_root(struct cgroup_root *root);
1592c9b2 TH	166	void init_cgroup_root(struct cgroup_root root, struct cgroup_sb_opts opts);
9732adc5	167	int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
0a268dbd	168	int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
1592c9b2 TH	169	struct dentry cgroup_do_mount(struct file_system_type fs_type, int flags,
	170	struct cgroup_root *root, unsigned long magic,
	171	struct cgroup_namespace *ns);
0a268dbd TH	172
0a268dbd TH	173	bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
e595cd70 TH	174	void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
	175	void cgroup_migrate_add_src(struct css_set src_cset, struct cgroup dst_cgrp,
	176	struct cgroup_mgctx *mgctx);
	177	int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
0a268dbd	178	int cgroup_migrate(struct task_struct *leader, bool threadgroup,
bfc2cf6f	179	struct cgroup_mgctx *mgctx);
0a268dbd TH	180
	181	int cgroup_attach_task(struct cgroup dst_cgrp, struct task_struct leader,
	182	bool threadgroup);
	183	ssize_t __cgroup_procs_write(struct kernfs_open_file of, char buf,
	184	size_t nbytes, loff_t off, bool threadgroup);
	185	ssize_t cgroup_procs_write(struct kernfs_open_file of, char buf, size_t nbytes,
	186	loff_t off);
	187
	188	void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
	189
1592c9b2 TH	190	int cgroup_mkdir(struct kernfs_node parent_kn, const char name, umode_t mode);
	191	int cgroup_rmdir(struct kernfs_node *kn);
	192	int cgroup_show_path(struct seq_file sf, struct kernfs_node kf_node,
	193	struct kernfs_root *kf_root);
	194
a28f8f5e WL	195	int cgroup_task_count(const struct cgroup *cgrp);
a28f8f5e WL	196
dcfe149b TH	197	/*
	198	* namespace.c
	199	*/
	200	extern const struct proc_ns_operations cgroupns_operations;
	201
0a268dbd TH	202	/*
	203	* cgroup-v1.c
	204	*/
d62beb7f	205	extern struct cftype cgroup1_base_files[];
0a268dbd	206	extern const struct file_operations proc_cgroupstats_operations;
1592c9b2	207	extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
0a268dbd	208
d62beb7f TH	209	bool cgroup1_ssid_disabled(int ssid);
	210	void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
	211	void cgroup1_release_agent(struct work_struct *work);
	212	void cgroup1_check_for_release(struct cgroup *cgrp);
1592c9b2 TH	213	struct dentry cgroup1_mount(struct file_system_type fs_type, int flags,
	214	void *data, unsigned long magic,
	215	struct cgroup_namespace *ns);
0a268dbd TH	216
0a268dbd TH	217	#endif /* __CGROUP_INTERNAL_H */