LXR linux/kernel/cgroup/cgroup-internal.h

   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>
   8#include <linux/refcount.h>
   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 */
  18struct 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
  30/* used to track tasks and csets during migration */
  31struct 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 */
  56struct 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;
  66
  67        /* subsystems affected by migration */
  68        u16                     ss_mask;
  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
  88struct 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
  98extern struct mutex cgroup_mutex;
  99extern spinlock_t css_set_lock;
 100extern struct cgroup_subsys *cgroup_subsys[];
 101extern struct list_head cgroup_roots;
 102extern 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
 117static inline bool cgroup_is_dead(const struct cgroup *cgrp)
 118{
 119        return !(cgrp->self.flags & CSS_ONLINE);
 120}
 121
 122static inline bool notify_on_release(const struct cgroup *cgrp)
 123{
 124        return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
 125}
 126
 127void put_css_set_locked(struct css_set *cset);
 128
 129static 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         */
 138        if (refcount_dec_not_one(&cset->refcount))
 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 */
 149static inline void get_css_set(struct css_set *cset)
 150{
 151        refcount_inc(&cset->refcount);
 152}
 153
 154bool cgroup_ssid_enabled(int ssid);
 155bool cgroup_on_dfl(const struct cgroup *cgrp);
 156
 157struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
 158struct cgroup *task_cgroup_from_root(struct task_struct *task,
 159                                     struct cgroup_root *root);
 160struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
 161void cgroup_kn_unlock(struct kernfs_node *kn);
 162int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
 163                          struct cgroup_namespace *ns);
 164
 165void cgroup_free_root(struct cgroup_root *root);
 166void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
 167int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
 168int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
 169struct 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);
 172
 173bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
 174void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
 175void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
 176                            struct cgroup_mgctx *mgctx);
 177int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
 178int cgroup_migrate(struct task_struct *leader, bool threadgroup,
 179                   struct cgroup_mgctx *mgctx);
 180
 181int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
 182                       bool threadgroup);
 183ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
 184                             size_t nbytes, loff_t off, bool threadgroup);
 185ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
 186                           loff_t off);
 187
 188void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
 189
 190int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
 191int cgroup_rmdir(struct kernfs_node *kn);
 192int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
 193                     struct kernfs_root *kf_root);
 194
 195/*
 196 * namespace.c
 197 */
 198extern const struct proc_ns_operations cgroupns_operations;
 199
 200/*
 201 * cgroup-v1.c
 202 */
 203extern struct cftype cgroup1_base_files[];
 204extern const struct file_operations proc_cgroupstats_operations;
 205extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
 206
 207bool cgroup1_ssid_disabled(int ssid);
 208void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
 209void cgroup1_release_agent(struct work_struct *work);
 210void cgroup1_check_for_release(struct cgroup *cgrp);
 211struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
 212                             void *data, unsigned long magic,
 213                             struct cgroup_namespace *ns);
 214
 215#endif /* __CGROUP_INTERNAL_H */
 216