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  */
  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
  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;
  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
  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
  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
 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          */
 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  */
 149 static inline void get_css_set(struct css_set *cset)
 150 {
 151         refcount_inc(&cset->refcount);
 152 }
 153
 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
 165 void cgroup_free_root(struct cgroup_root *root);
 166 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
 167 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
 168 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
 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);
 172
 173 bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
 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);
 178 int cgroup_migrate(struct task_struct *leader, bool threadgroup,
 179                    struct cgroup_mgctx *mgctx);
 180
 181 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
 182                        bool threadgroup);
 183 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
 184         __acquires(&cgroup_threadgroup_rwsem);
 185 void cgroup_procs_write_finish(struct task_struct *task)
 186         __releases(&cgroup_threadgroup_rwsem);
 187
 188 void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
 189
 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
 195 int cgroup_task_count(const struct cgroup *cgrp);
 196
 197 /*
 198  * namespace.c
 199  */
 200 extern const struct proc_ns_operations cgroupns_operations;
 201
 202 /*
 203  * cgroup-v1.c
 204  */
 205 extern struct cftype cgroup1_base_files[];
 206 extern const struct file_operations proc_cgroupstats_operations;
 207 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
 208
 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);
 213 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
 214                              void *data, unsigned long magic,
 215                              struct cgroup_namespace *ns);
 216
 217 #endif /* __CGROUP_INTERNAL_H */