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
];
14 extern bool cgroup_debug
;
15 extern void __init
enable_debug_cgroup(void);
18 * cgroup_path() takes a spin lock. It is good practice not to take
19 * spin locks within trace point handlers, as they are mostly hidden
20 * from normal view. As cgroup_path() can take the kernfs_rename_lock
21 * spin lock, it is best to not call that function from the trace event
24 * Note: trace_cgroup_##type##_enabled() is a static branch that will only
25 * be set when the trace event is enabled.
27 #define TRACE_CGROUP_PATH(type, cgrp, ...) \
29 if (trace_cgroup_##type##_enabled()) { \
30 spin_lock(&trace_cgroup_path_lock); \
31 cgroup_path(cgrp, trace_cgroup_path, \
32 TRACE_CGROUP_PATH_LEN); \
33 trace_cgroup_##type(cgrp, trace_cgroup_path, \
35 spin_unlock(&trace_cgroup_path_lock); \
40 * A cgroup can be associated with multiple css_sets as different tasks may
41 * belong to different cgroups on different hierarchies. In the other
42 * direction, a css_set is naturally associated with multiple cgroups.
43 * This M:N relationship is represented by the following link structure
44 * which exists for each association and allows traversing the associations
47 struct cgrp_cset_link
{
48 /* the cgroup and css_set this link associates */
52 /* list of cgrp_cset_links anchored at cgrp->cset_links */
53 struct list_head cset_link
;
55 /* list of cgrp_cset_links anchored at css_set->cgrp_links */
56 struct list_head cgrp_link
;
59 /* used to track tasks and csets during migration */
60 struct cgroup_taskset
{
61 /* the src and dst cset list running through cset->mg_node */
62 struct list_head src_csets
;
63 struct list_head dst_csets
;
65 /* the number of tasks in the set */
68 /* the subsys currently being processed */
72 * Fields for cgroup_taskset_*() iteration.
74 * Before migration is committed, the target migration tasks are on
75 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of
76 * the csets on ->dst_csets. ->csets point to either ->src_csets
77 * or ->dst_csets depending on whether migration is committed.
79 * ->cur_csets and ->cur_task point to the current task position
82 struct list_head
*csets
;
83 struct css_set
*cur_cset
;
84 struct task_struct
*cur_task
;
87 /* migration context also tracks preloading */
90 * Preloaded source and destination csets. Used to guarantee
91 * atomic success or failure on actual migration.
93 struct list_head preloaded_src_csets
;
94 struct list_head preloaded_dst_csets
;
96 /* tasks and csets to migrate */
97 struct cgroup_taskset tset
;
99 /* subsystems affected by migration */
103 #define CGROUP_TASKSET_INIT(tset) \
105 .src_csets = LIST_HEAD_INIT(tset.src_csets), \
106 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \
107 .csets = &tset.src_csets, \
110 #define CGROUP_MGCTX_INIT(name) \
112 LIST_HEAD_INIT(name.preloaded_src_csets), \
113 LIST_HEAD_INIT(name.preloaded_dst_csets), \
114 CGROUP_TASKSET_INIT(name.tset), \
117 #define DEFINE_CGROUP_MGCTX(name) \
118 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
120 struct cgroup_sb_opts
{
124 bool cpuset_clone_children
;
126 /* User explicitly requested empty subsystem */
130 extern struct mutex cgroup_mutex
;
131 extern spinlock_t css_set_lock
;
132 extern struct cgroup_subsys
*cgroup_subsys
[];
133 extern struct list_head cgroup_roots
;
134 extern struct file_system_type cgroup_fs_type
;
136 /* iterate across the hierarchies */
137 #define for_each_root(root) \
138 list_for_each_entry((root), &cgroup_roots, root_list)
141 * for_each_subsys - iterate all enabled cgroup subsystems
142 * @ss: the iteration cursor
143 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
145 #define for_each_subsys(ss, ssid) \
146 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
147 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
149 static inline bool cgroup_is_dead(const struct cgroup
*cgrp
)
151 return !(cgrp
->self
.flags
& CSS_ONLINE
);
154 static inline bool notify_on_release(const struct cgroup
*cgrp
)
156 return test_bit(CGRP_NOTIFY_ON_RELEASE
, &cgrp
->flags
);
159 void put_css_set_locked(struct css_set
*cset
);
161 static inline void put_css_set(struct css_set
*cset
)
166 * Ensure that the refcount doesn't hit zero while any readers
167 * can see it. Similar to atomic_dec_and_lock(), but for an
170 if (refcount_dec_not_one(&cset
->refcount
))
173 spin_lock_irqsave(&css_set_lock
, flags
);
174 put_css_set_locked(cset
);
175 spin_unlock_irqrestore(&css_set_lock
, flags
);
179 * refcounted get/put for css_set objects
181 static inline void get_css_set(struct css_set
*cset
)
183 refcount_inc(&cset
->refcount
);
186 bool cgroup_ssid_enabled(int ssid
);
187 bool cgroup_on_dfl(const struct cgroup
*cgrp
);
188 bool cgroup_is_thread_root(struct cgroup
*cgrp
);
189 bool cgroup_is_threaded(struct cgroup
*cgrp
);
191 struct cgroup_root
*cgroup_root_from_kf(struct kernfs_root
*kf_root
);
192 struct cgroup
*task_cgroup_from_root(struct task_struct
*task
,
193 struct cgroup_root
*root
);
194 struct cgroup
*cgroup_kn_lock_live(struct kernfs_node
*kn
, bool drain_offline
);
195 void cgroup_kn_unlock(struct kernfs_node
*kn
);
196 int cgroup_path_ns_locked(struct cgroup
*cgrp
, char *buf
, size_t buflen
,
197 struct cgroup_namespace
*ns
);
199 void cgroup_free_root(struct cgroup_root
*root
);
200 void init_cgroup_root(struct cgroup_root
*root
, struct cgroup_sb_opts
*opts
);
201 int cgroup_setup_root(struct cgroup_root
*root
, u16 ss_mask
, int ref_flags
);
202 int rebind_subsystems(struct cgroup_root
*dst_root
, u16 ss_mask
);
203 struct dentry
*cgroup_do_mount(struct file_system_type
*fs_type
, int flags
,
204 struct cgroup_root
*root
, unsigned long magic
,
205 struct cgroup_namespace
*ns
);
207 int cgroup_migrate_vet_dst(struct cgroup
*dst_cgrp
);
208 void cgroup_migrate_finish(struct cgroup_mgctx
*mgctx
);
209 void cgroup_migrate_add_src(struct css_set
*src_cset
, struct cgroup
*dst_cgrp
,
210 struct cgroup_mgctx
*mgctx
);
211 int cgroup_migrate_prepare_dst(struct cgroup_mgctx
*mgctx
);
212 int cgroup_migrate(struct task_struct
*leader
, bool threadgroup
,
213 struct cgroup_mgctx
*mgctx
);
215 int cgroup_attach_task(struct cgroup
*dst_cgrp
, struct task_struct
*leader
,
217 struct task_struct
*cgroup_procs_write_start(char *buf
, bool threadgroup
)
218 __acquires(&cgroup_threadgroup_rwsem
);
219 void cgroup_procs_write_finish(struct task_struct
*task
)
220 __releases(&cgroup_threadgroup_rwsem
);
222 void cgroup_lock_and_drain_offline(struct cgroup
*cgrp
);
224 int cgroup_mkdir(struct kernfs_node
*parent_kn
, const char *name
, umode_t mode
);
225 int cgroup_rmdir(struct kernfs_node
*kn
);
226 int cgroup_show_path(struct seq_file
*sf
, struct kernfs_node
*kf_node
,
227 struct kernfs_root
*kf_root
);
229 int cgroup_task_count(const struct cgroup
*cgrp
);
234 int cgroup_rstat_init(struct cgroup
*cgrp
);
235 void cgroup_rstat_exit(struct cgroup
*cgrp
);
236 void cgroup_rstat_boot(void);
237 void cgroup_base_stat_cputime_show(struct seq_file
*seq
);
242 extern const struct proc_ns_operations cgroupns_operations
;
247 extern struct cftype cgroup1_base_files
[];
248 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops
;
250 int proc_cgroupstats_show(struct seq_file
*m
, void *v
);
251 bool cgroup1_ssid_disabled(int ssid
);
252 void cgroup1_pidlist_destroy_all(struct cgroup
*cgrp
);
253 void cgroup1_release_agent(struct work_struct
*work
);
254 void cgroup1_check_for_release(struct cgroup
*cgrp
);
255 struct dentry
*cgroup1_mount(struct file_system_type
*fs_type
, int flags
,
256 void *data
, unsigned long magic
,
257 struct cgroup_namespace
*ns
);
259 #endif /* __CGROUP_INTERNAL_H */