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 number of tasks in the set */
  37         int                     nr_tasks;
  38
  39         /* the subsys currently being processed */
  40         int                     ssid;
  41
  42         /*
  43          * Fields for cgroup_taskset_*() iteration.
  44          *
  45          * Before migration is committed, the target migration tasks are on
  46          * ->mg_tasks of the csets on ->src_csets.  After, on ->mg_tasks of
  47          * the csets on ->dst_csets.  ->csets point to either ->src_csets
  48          * or ->dst_csets depending on whether migration is committed.
  49          *
  50          * ->cur_csets and ->cur_task point to the current task position
  51          * during iteration.
  52          */
  53         struct list_head        *csets;
  54         struct css_set          *cur_cset;
  55         struct task_struct      *cur_task;
  56 };
  57
  58 /* migration context also tracks preloading */
  59 struct cgroup_mgctx {
  60         /*
  61          * Preloaded source and destination csets.  Used to guarantee
  62          * atomic success or failure on actual migration.
  63          */
  64         struct list_head        preloaded_src_csets;
  65         struct list_head        preloaded_dst_csets;
  66
  67         /* tasks and csets to migrate */
  68         struct cgroup_taskset   tset;
  69
  70         /* subsystems affected by migration */
  71         u16                     ss_mask;
  72 };
  73
  74 #define CGROUP_TASKSET_INIT(tset)                                               \
  75 {                                                                               \
  76         .src_csets              = LIST_HEAD_INIT(tset.src_csets),               \
  77         .dst_csets              = LIST_HEAD_INIT(tset.dst_csets),               \
  78         .csets                  = &tset.src_csets,                              \
  79 }
  80
  81 #define CGROUP_MGCTX_INIT(name)                                                 \
  82 {                                                                               \
  83         LIST_HEAD_INIT(name.preloaded_src_csets),                               \
  84         LIST_HEAD_INIT(name.preloaded_dst_csets),                               \
  85         CGROUP_TASKSET_INIT(name.tset),                                         \
  86 }
  87
  88 #define DEFINE_CGROUP_MGCTX(name)                                               \
  89         struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
  90
  91 struct cgroup_sb_opts {
  92         u16 subsys_mask;
  93         unsigned int flags;
  94         char *release_agent;
  95         bool cpuset_clone_children;
  96         char *name;
  97         /* User explicitly requested empty subsystem */
  98         bool none;
  99 };
 100
 101 extern struct mutex cgroup_mutex;
 102 extern spinlock_t css_set_lock;
 103 extern struct cgroup_subsys *cgroup_subsys[];
 104 extern struct list_head cgroup_roots;
 105 extern struct file_system_type cgroup_fs_type;
 106
 107 /* iterate across the hierarchies */
 108 #define for_each_root(root)                                             \
 109         list_for_each_entry((root), &cgroup_roots, root_list)
 110
 111 /**
 112  * for_each_subsys - iterate all enabled cgroup subsystems
 113  * @ss: the iteration cursor
 114  * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
 115  */
 116 #define for_each_subsys(ss, ssid)                                       \
 117         for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT &&                \
 118              (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
 119
 120 static inline bool cgroup_is_dead(const struct cgroup *cgrp)
 121 {
 122         return !(cgrp->self.flags & CSS_ONLINE);
 123 }
 124
 125 static inline bool notify_on_release(const struct cgroup *cgrp)
 126 {
 127         return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
 128 }
 129
 130 void put_css_set_locked(struct css_set *cset);
 131
 132 static inline void put_css_set(struct css_set *cset)
 133 {
 134         unsigned long flags;
 135
 136         /*
 137          * Ensure that the refcount doesn't hit zero while any readers
 138          * can see it. Similar to atomic_dec_and_lock(), but for an
 139          * rwlock
 140          */
 141         if (refcount_dec_not_one(&cset->refcount))
 142                 return;
 143
 144         spin_lock_irqsave(&css_set_lock, flags);
 145         put_css_set_locked(cset);
 146         spin_unlock_irqrestore(&css_set_lock, flags);
 147 }
 148
 149 /*
 150  * refcounted get/put for css_set objects
 151  */
 152 static inline void get_css_set(struct css_set *cset)
 153 {
 154         refcount_inc(&cset->refcount);
 155 }
 156
 157 bool cgroup_ssid_enabled(int ssid);
 158 bool cgroup_on_dfl(const struct cgroup *cgrp);
 159
 160 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
 161 struct cgroup *task_cgroup_from_root(struct task_struct *task,
 162                                      struct cgroup_root *root);
 163 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
 164 void cgroup_kn_unlock(struct kernfs_node *kn);
 165 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
 166                           struct cgroup_namespace *ns);
 167
 168 void cgroup_free_root(struct cgroup_root *root);
 169 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
 170 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
 171 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
 172 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
 173                                struct cgroup_root *root, unsigned long magic,
 174                                struct cgroup_namespace *ns);
 175
 176 bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
 177 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
 178 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
 179                             struct cgroup_mgctx *mgctx);
 180 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
 181 int cgroup_migrate(struct task_struct *leader, bool threadgroup,
 182                    struct cgroup_mgctx *mgctx);
 183
 184 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
 185                        bool threadgroup);
 186 ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
 187                              size_t nbytes, loff_t off, bool threadgroup);
 188 ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
 189                            loff_t off);
 190
 191 void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
 192
 193 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
 194 int cgroup_rmdir(struct kernfs_node *kn);
 195 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
 196                      struct kernfs_root *kf_root);
 197
 198 int cgroup_task_count(const struct cgroup *cgrp);
 199
 200 /*
 201  * namespace.c
 202  */
 203 extern const struct proc_ns_operations cgroupns_operations;
 204
 205 /*
 206  * cgroup-v1.c
 207  */
 208 extern struct cftype cgroup1_base_files[];
 209 extern const struct file_operations proc_cgroupstats_operations;
 210 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
 211
 212 bool cgroup1_ssid_disabled(int ssid);
 213 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
 214 void cgroup1_release_agent(struct work_struct *work);
 215 void cgroup1_check_for_release(struct cgroup *cgrp);
 216 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
 217                              void *data, unsigned long magic,
 218                              struct cgroup_namespace *ns);
 219
 220 #endif /* __CGROUP_INTERNAL_H */