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