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Release 4.15 kernel/cgroup/cgroup-internal.h

Directory: kernel/cgroup
/* SPDX-License-Identifier: GPL-2.0 */
#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 number of tasks in the set */
	
int			nr_tasks;

	/* 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); }

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

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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); }

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

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bool cgroup_ssid_enabled(int ssid); bool cgroup_on_dfl(const struct cgroup *cgrp); bool cgroup_is_thread_root(struct cgroup *cgrp); bool cgroup_is_threaded(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); int cgroup_migrate_vet_dst(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); struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) __acquires(&cgroup_threadgroup_rwsem ); void cgroup_procs_write_finish(struct task_struct *task) __releases(&cgroup_threadgroup_rwsem ); 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); /* * stat.c */ void cgroup_stat_flush(struct cgroup *cgrp); int cgroup_stat_init(struct cgroup *cgrp); void cgroup_stat_exit(struct cgroup *cgrp); void cgroup_stat_show_cputime(struct seq_file *seq); void cgroup_stat_boot(void); /* * 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 */

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Directory: kernel/cgroup
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