1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __CGROUP_INTERNAL_H
3 #define __CGROUP_INTERNAL_H
5 #include <linux/cgroup.h>
6 #include <linux/kernfs.h>
7 #include <linux/workqueue.h>
8 #include <linux/list.h>
9 #include <linux/refcount.h>
11 #define TRACE_CGROUP_PATH_LEN 1024
12 extern spinlock_t trace_cgroup_path_lock;
13 extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
16 * cgroup_path() takes a spin lock. It is good practice not to take
17 * spin locks within trace point handlers, as they are mostly hidden
18 * from normal view. As cgroup_path() can take the kernfs_rename_lock
19 * spin lock, it is best to not call that function from the trace event
22 * Note: trace_cgroup_##type##_enabled() is a static branch that will only
23 * be set when the trace event is enabled.
25 #define TRACE_CGROUP_PATH(type, cgrp, ...) \
27 if (trace_cgroup_##type##_enabled()) { \
28 spin_lock(&trace_cgroup_path_lock); \
29 cgroup_path(cgrp, trace_cgroup_path, \
30 TRACE_CGROUP_PATH_LEN); \
31 trace_cgroup_##type(cgrp, trace_cgroup_path, \
33 spin_unlock(&trace_cgroup_path_lock); \
37 struct cgroup_pidlist;
39 struct cgroup_file_ctx {
40 struct cgroup_namespace *ns;
48 struct css_task_iter iter;
52 struct cgroup_pidlist *pidlist;
57 * A cgroup can be associated with multiple css_sets as different tasks may
58 * belong to different cgroups on different hierarchies. In the other
59 * direction, a css_set is naturally associated with multiple cgroups.
60 * This M:N relationship is represented by the following link structure
61 * which exists for each association and allows traversing the associations
64 struct cgrp_cset_link {
65 /* the cgroup and css_set this link associates */
69 /* list of cgrp_cset_links anchored at cgrp->cset_links */
70 struct list_head cset_link;
72 /* list of cgrp_cset_links anchored at css_set->cgrp_links */
73 struct list_head cgrp_link;
76 /* used to track tasks and csets during migration */
77 struct cgroup_taskset {
78 /* the src and dst cset list running through cset->mg_node */
79 struct list_head src_csets;
80 struct list_head dst_csets;
82 /* the number of tasks in the set */
85 /* the subsys currently being processed */
89 * Fields for cgroup_taskset_*() iteration.
91 * Before migration is committed, the target migration tasks are on
92 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of
93 * the csets on ->dst_csets. ->csets point to either ->src_csets
94 * or ->dst_csets depending on whether migration is committed.
96 * ->cur_csets and ->cur_task point to the current task position
99 struct list_head *csets;
100 struct css_set *cur_cset;
101 struct task_struct *cur_task;
104 /* migration context also tracks preloading */
105 struct cgroup_mgctx {
107 * Preloaded source and destination csets. Used to guarantee
108 * atomic success or failure on actual migration.
110 struct list_head preloaded_src_csets;
111 struct list_head preloaded_dst_csets;
113 /* tasks and csets to migrate */
114 struct cgroup_taskset tset;
116 /* subsystems affected by migration */
120 #define CGROUP_TASKSET_INIT(tset) \
122 .src_csets = LIST_HEAD_INIT(tset.src_csets), \
123 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \
124 .csets = &tset.src_csets, \
127 #define CGROUP_MGCTX_INIT(name) \
129 LIST_HEAD_INIT(name.preloaded_src_csets), \
130 LIST_HEAD_INIT(name.preloaded_dst_csets), \
131 CGROUP_TASKSET_INIT(name.tset), \
134 #define DEFINE_CGROUP_MGCTX(name) \
135 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
137 struct cgroup_sb_opts {
141 bool cpuset_clone_children;
143 /* User explicitly requested empty subsystem */
147 extern struct mutex cgroup_mutex;
148 extern spinlock_t css_set_lock;
149 extern struct cgroup_subsys *cgroup_subsys[];
150 extern struct list_head cgroup_roots;
151 extern struct file_system_type cgroup_fs_type;
153 /* iterate across the hierarchies */
154 #define for_each_root(root) \
155 list_for_each_entry((root), &cgroup_roots, root_list)
158 * for_each_subsys - iterate all enabled cgroup subsystems
159 * @ss: the iteration cursor
160 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
162 #define for_each_subsys(ss, ssid) \
163 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
164 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
166 static inline bool cgroup_is_dead(const struct cgroup *cgrp)
168 return !(cgrp->self.flags & CSS_ONLINE);
171 static inline bool notify_on_release(const struct cgroup *cgrp)
173 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
176 void put_css_set_locked(struct css_set *cset);
178 static inline void put_css_set(struct css_set *cset)
183 * Ensure that the refcount doesn't hit zero while any readers
184 * can see it. Similar to atomic_dec_and_lock(), but for an
187 if (refcount_dec_not_one(&cset->refcount))
190 spin_lock_irqsave(&css_set_lock, flags);
191 put_css_set_locked(cset);
192 spin_unlock_irqrestore(&css_set_lock, flags);
196 * refcounted get/put for css_set objects
198 static inline void get_css_set(struct css_set *cset)
200 refcount_inc(&cset->refcount);
203 bool cgroup_ssid_enabled(int ssid);
204 bool cgroup_on_dfl(const struct cgroup *cgrp);
205 bool cgroup_is_thread_root(struct cgroup *cgrp);
206 bool cgroup_is_threaded(struct cgroup *cgrp);
208 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
209 struct cgroup *task_cgroup_from_root(struct task_struct *task,
210 struct cgroup_root *root);
211 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
212 void cgroup_kn_unlock(struct kernfs_node *kn);
213 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
214 struct cgroup_namespace *ns);
216 void cgroup_free_root(struct cgroup_root *root);
217 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
218 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
219 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
220 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
221 struct cgroup_root *root, unsigned long magic,
222 struct cgroup_namespace *ns);
224 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
225 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
226 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
227 struct cgroup_mgctx *mgctx);
228 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
229 int cgroup_migrate(struct task_struct *leader, bool threadgroup,
230 struct cgroup_mgctx *mgctx);
232 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
234 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
235 __acquires(&cgroup_threadgroup_rwsem);
236 void cgroup_procs_write_finish(struct task_struct *task)
237 __releases(&cgroup_threadgroup_rwsem);
239 void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
241 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
242 int cgroup_rmdir(struct kernfs_node *kn);
243 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
244 struct kernfs_root *kf_root);
246 int cgroup_task_count(const struct cgroup *cgrp);
251 int cgroup_rstat_init(struct cgroup *cgrp);
252 void cgroup_rstat_exit(struct cgroup *cgrp);
253 void cgroup_rstat_boot(void);
254 void cgroup_base_stat_cputime_show(struct seq_file *seq);
259 extern const struct proc_ns_operations cgroupns_operations;
264 extern struct cftype cgroup1_base_files[];
265 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
267 int proc_cgroupstats_show(struct seq_file *m, void *v);
268 bool cgroup1_ssid_disabled(int ssid);
269 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
270 void cgroup1_release_agent(struct work_struct *work);
271 void cgroup1_check_for_release(struct cgroup *cgrp);
272 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
273 void *data, unsigned long magic,
274 struct cgroup_namespace *ns);
276 #endif /* __CGROUP_INTERNAL_H */