Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1 | #ifndef _LINUX_CGROUP_H |
| 2 | #define _LINUX_CGROUP_H |
| 3 | /* |
| 4 | * cgroup interface |
| 5 | * |
| 6 | * Copyright (C) 2003 BULL SA |
| 7 | * Copyright (C) 2004-2006 Silicon Graphics, Inc. |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/sched.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 12 | #include <linux/cpumask.h> |
| 13 | #include <linux/nodemask.h> |
Tejun Heo | eb6fd50 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 14 | #include <linux/rculist.h> |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 15 | #include <linux/cgroupstats.h> |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 16 | #include <linux/fs.h> |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 17 | #include <linux/seq_file.h> |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 18 | #include <linux/kernfs.h> |
Tejun Heo | 49d1dc4 | 2015-09-18 11:56:28 -0400 | [diff] [blame] | 19 | #include <linux/jump_label.h> |
Tejun Heo | b4a04ab | 2015-05-13 15:38:40 -0400 | [diff] [blame] | 20 | |
| 21 | #include <linux/cgroup-defs.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 22 | |
| 23 | #ifdef CONFIG_CGROUPS |
| 24 | |
Tejun Heo | 6abc8ca | 2015-08-04 15:20:55 -0400 | [diff] [blame] | 25 | /* |
| 26 | * All weight knobs on the default hierarhcy should use the following min, |
| 27 | * default and max values. The default value is the logarithmic center of |
| 28 | * MIN and MAX and allows 100x to be expressed in both directions. |
| 29 | */ |
| 30 | #define CGROUP_WEIGHT_MIN 1 |
| 31 | #define CGROUP_WEIGHT_DFL 100 |
| 32 | #define CGROUP_WEIGHT_MAX 10000 |
| 33 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 34 | /* a css_task_iter should be treated as an opaque object */ |
| 35 | struct css_task_iter { |
| 36 | struct cgroup_subsys *ss; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 37 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 38 | struct list_head *cset_pos; |
| 39 | struct list_head *cset_head; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 40 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 41 | struct list_head *task_pos; |
| 42 | struct list_head *tasks_head; |
| 43 | struct list_head *mg_tasks_head; |
Tejun Heo | ed27b9f | 2015-10-15 16:41:52 -0400 | [diff] [blame] | 44 | |
| 45 | struct css_set *cur_cset; |
| 46 | struct task_struct *cur_task; |
| 47 | struct list_head iters_node; /* css_set->task_iters */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 48 | }; |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 49 | |
| 50 | extern struct cgroup_root cgrp_dfl_root; |
| 51 | extern struct css_set init_css_set; |
| 52 | |
| 53 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
| 54 | #include <linux/cgroup_subsys.h> |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 55 | #undef SUBSYS |
| 56 | |
Tejun Heo | 49d1dc4 | 2015-09-18 11:56:28 -0400 | [diff] [blame] | 57 | #define SUBSYS(_x) \ |
| 58 | extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ |
| 59 | extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; |
| 60 | #include <linux/cgroup_subsys.h> |
| 61 | #undef SUBSYS |
| 62 | |
| 63 | /** |
| 64 | * cgroup_subsys_enabled - fast test on whether a subsys is enabled |
| 65 | * @ss: subsystem in question |
| 66 | */ |
| 67 | #define cgroup_subsys_enabled(ss) \ |
| 68 | static_branch_likely(&ss ## _enabled_key) |
| 69 | |
| 70 | /** |
| 71 | * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy |
| 72 | * @ss: subsystem in question |
| 73 | */ |
| 74 | #define cgroup_subsys_on_dfl(ss) \ |
| 75 | static_branch_likely(&ss ## _on_dfl_key) |
| 76 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 77 | bool css_has_online_children(struct cgroup_subsys_state *css); |
| 78 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); |
| 79 | struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, |
| 80 | struct cgroup_subsys *ss); |
| 81 | struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, |
| 82 | struct cgroup_subsys *ss); |
| 83 | |
Tejun Heo | 16af439 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 84 | struct cgroup *cgroup_get_from_path(const char *path); |
| 85 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 86 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
| 87 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
| 88 | |
| 89 | int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
| 90 | int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
| 91 | int cgroup_rm_cftypes(struct cftype *cfts); |
Tejun Heo | 34c0625 | 2015-11-05 00:12:24 -0500 | [diff] [blame] | 92 | void cgroup_file_notify(struct cgroup_file *cfile); |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 93 | |
| 94 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); |
| 95 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); |
| 96 | int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, |
| 97 | struct pid *pid, struct task_struct *tsk); |
| 98 | |
| 99 | void cgroup_fork(struct task_struct *p); |
Oleg Nesterov | b53202e | 2015-12-03 10:24:08 -0500 | [diff] [blame] | 100 | extern int cgroup_can_fork(struct task_struct *p); |
| 101 | extern void cgroup_cancel_fork(struct task_struct *p); |
| 102 | extern void cgroup_post_fork(struct task_struct *p); |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 103 | void cgroup_exit(struct task_struct *p); |
Tejun Heo | 2e91fa7 | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 104 | void cgroup_free(struct task_struct *p); |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 105 | |
| 106 | int cgroup_init_early(void); |
| 107 | int cgroup_init(void); |
| 108 | |
Tejun Heo | 5c9d535 | 2014-05-16 13:22:48 -0400 | [diff] [blame] | 109 | /* |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 110 | * Iteration helpers and macros. |
Tejun Heo | 5c9d535 | 2014-05-16 13:22:48 -0400 | [diff] [blame] | 111 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 112 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 113 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, |
| 114 | struct cgroup_subsys_state *parent); |
| 115 | struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, |
| 116 | struct cgroup_subsys_state *css); |
| 117 | struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); |
| 118 | struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, |
| 119 | struct cgroup_subsys_state *css); |
Tejun Heo | 72c97e5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 120 | |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 121 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, |
| 122 | struct cgroup_subsys_state **dst_cssp); |
| 123 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, |
| 124 | struct cgroup_subsys_state **dst_cssp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 125 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 126 | void css_task_iter_start(struct cgroup_subsys_state *css, |
| 127 | struct css_task_iter *it); |
| 128 | struct task_struct *css_task_iter_next(struct css_task_iter *it); |
| 129 | void css_task_iter_end(struct css_task_iter *it); |
Tejun Heo | 0ae78e0 | 2013-08-13 11:01:54 -0400 | [diff] [blame] | 130 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 131 | /** |
| 132 | * css_for_each_child - iterate through children of a css |
| 133 | * @pos: the css * to use as the loop cursor |
| 134 | * @parent: css whose children to walk |
| 135 | * |
| 136 | * Walk @parent's children. Must be called under rcu_read_lock(). |
| 137 | * |
| 138 | * If a subsystem synchronizes ->css_online() and the start of iteration, a |
| 139 | * css which finished ->css_online() is guaranteed to be visible in the |
| 140 | * future iterations and will stay visible until the last reference is put. |
| 141 | * A css which hasn't finished ->css_online() or already finished |
| 142 | * ->css_offline() may show up during traversal. It's each subsystem's |
| 143 | * responsibility to synchronize against on/offlining. |
| 144 | * |
| 145 | * It is allowed to temporarily drop RCU read lock during iteration. The |
| 146 | * caller is responsible for ensuring that @pos remains accessible until |
| 147 | * the start of the next iteration by, for example, bumping the css refcnt. |
| 148 | */ |
| 149 | #define css_for_each_child(pos, parent) \ |
| 150 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ |
| 151 | (pos) = css_next_child((pos), (parent))) |
Tejun Heo | d5c419b | 2014-05-16 13:22:48 -0400 | [diff] [blame] | 152 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 153 | /** |
| 154 | * css_for_each_descendant_pre - pre-order walk of a css's descendants |
| 155 | * @pos: the css * to use as the loop cursor |
| 156 | * @root: css whose descendants to walk |
| 157 | * |
| 158 | * Walk @root's descendants. @root is included in the iteration and the |
| 159 | * first node to be visited. Must be called under rcu_read_lock(). |
| 160 | * |
| 161 | * If a subsystem synchronizes ->css_online() and the start of iteration, a |
| 162 | * css which finished ->css_online() is guaranteed to be visible in the |
| 163 | * future iterations and will stay visible until the last reference is put. |
| 164 | * A css which hasn't finished ->css_online() or already finished |
| 165 | * ->css_offline() may show up during traversal. It's each subsystem's |
| 166 | * responsibility to synchronize against on/offlining. |
| 167 | * |
| 168 | * For example, the following guarantees that a descendant can't escape |
| 169 | * state updates of its ancestors. |
| 170 | * |
| 171 | * my_online(@css) |
| 172 | * { |
| 173 | * Lock @css's parent and @css; |
| 174 | * Inherit state from the parent; |
| 175 | * Unlock both. |
| 176 | * } |
| 177 | * |
| 178 | * my_update_state(@css) |
| 179 | * { |
| 180 | * css_for_each_descendant_pre(@pos, @css) { |
| 181 | * Lock @pos; |
| 182 | * if (@pos == @css) |
| 183 | * Update @css's state; |
| 184 | * else |
| 185 | * Verify @pos is alive and inherit state from its parent; |
| 186 | * Unlock @pos; |
| 187 | * } |
| 188 | * } |
| 189 | * |
| 190 | * As long as the inheriting step, including checking the parent state, is |
| 191 | * enclosed inside @pos locking, double-locking the parent isn't necessary |
| 192 | * while inheriting. The state update to the parent is guaranteed to be |
| 193 | * visible by walking order and, as long as inheriting operations to the |
| 194 | * same @pos are atomic to each other, multiple updates racing each other |
| 195 | * still result in the correct state. It's guaranateed that at least one |
| 196 | * inheritance happens for any css after the latest update to its parent. |
| 197 | * |
| 198 | * If checking parent's state requires locking the parent, each inheriting |
| 199 | * iteration should lock and unlock both @pos->parent and @pos. |
| 200 | * |
| 201 | * Alternatively, a subsystem may choose to use a single global lock to |
| 202 | * synchronize ->css_online() and ->css_offline() against tree-walking |
| 203 | * operations. |
| 204 | * |
| 205 | * It is allowed to temporarily drop RCU read lock during iteration. The |
| 206 | * caller is responsible for ensuring that @pos remains accessible until |
| 207 | * the start of the next iteration by, for example, bumping the css refcnt. |
| 208 | */ |
| 209 | #define css_for_each_descendant_pre(pos, css) \ |
| 210 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ |
| 211 | (pos) = css_next_descendant_pre((pos), (css))) |
Tejun Heo | 15a4c83 | 2014-05-04 15:09:14 -0400 | [diff] [blame] | 212 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 213 | /** |
| 214 | * css_for_each_descendant_post - post-order walk of a css's descendants |
| 215 | * @pos: the css * to use as the loop cursor |
| 216 | * @css: css whose descendants to walk |
| 217 | * |
| 218 | * Similar to css_for_each_descendant_pre() but performs post-order |
| 219 | * traversal instead. @root is included in the iteration and the last |
| 220 | * node to be visited. |
| 221 | * |
| 222 | * If a subsystem synchronizes ->css_online() and the start of iteration, a |
| 223 | * css which finished ->css_online() is guaranteed to be visible in the |
| 224 | * future iterations and will stay visible until the last reference is put. |
| 225 | * A css which hasn't finished ->css_online() or already finished |
| 226 | * ->css_offline() may show up during traversal. It's each subsystem's |
| 227 | * responsibility to synchronize against on/offlining. |
| 228 | * |
| 229 | * Note that the walk visibility guarantee example described in pre-order |
| 230 | * walk doesn't apply the same to post-order walks. |
| 231 | */ |
| 232 | #define css_for_each_descendant_post(pos, css) \ |
| 233 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ |
| 234 | (pos) = css_next_descendant_post((pos), (css))) |
Tejun Heo | 48ddbe1 | 2012-04-01 12:09:56 -0700 | [diff] [blame] | 235 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 236 | /** |
| 237 | * cgroup_taskset_for_each - iterate cgroup_taskset |
| 238 | * @task: the loop cursor |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 239 | * @dst_css: the destination css |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 240 | * @tset: taskset to iterate |
Tejun Heo | 4530edd | 2015-09-11 15:00:19 -0400 | [diff] [blame] | 241 | * |
| 242 | * @tset may contain multiple tasks and they may belong to multiple |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 243 | * processes. |
| 244 | * |
| 245 | * On the v2 hierarchy, there may be tasks from multiple processes and they |
| 246 | * may not share the source or destination csses. |
| 247 | * |
| 248 | * On traditional hierarchies, when there are multiple tasks in @tset, if a |
| 249 | * task of a process is in @tset, all tasks of the process are in @tset. |
| 250 | * Also, all are guaranteed to share the same source and destination csses. |
Tejun Heo | 4530edd | 2015-09-11 15:00:19 -0400 | [diff] [blame] | 251 | * |
| 252 | * Iteration is not in any specific order. |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 253 | */ |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 254 | #define cgroup_taskset_for_each(task, dst_css, tset) \ |
| 255 | for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ |
| 256 | (task); \ |
| 257 | (task) = cgroup_taskset_next((tset), &(dst_css))) |
Tejun Heo | 0cb51d7 | 2014-05-16 13:22:49 -0400 | [diff] [blame] | 258 | |
Tejun Heo | 4530edd | 2015-09-11 15:00:19 -0400 | [diff] [blame] | 259 | /** |
| 260 | * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset |
| 261 | * @leader: the loop cursor |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 262 | * @dst_css: the destination css |
Tejun Heo | 4530edd | 2015-09-11 15:00:19 -0400 | [diff] [blame] | 263 | * @tset: takset to iterate |
| 264 | * |
| 265 | * Iterate threadgroup leaders of @tset. For single-task migrations, @tset |
| 266 | * may not contain any. |
| 267 | */ |
Tejun Heo | 1f7dd3e5 | 2015-12-03 10:18:21 -0500 | [diff] [blame] | 268 | #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ |
| 269 | for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ |
| 270 | (leader); \ |
| 271 | (leader) = cgroup_taskset_next((tset), &(dst_css))) \ |
Tejun Heo | 4530edd | 2015-09-11 15:00:19 -0400 | [diff] [blame] | 272 | if ((leader) != (leader)->group_leader) \ |
| 273 | ; \ |
| 274 | else |
| 275 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 276 | /* |
| 277 | * Inline functions. |
| 278 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 279 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 280 | /** |
| 281 | * css_get - obtain a reference on the specified css |
| 282 | * @css: target css |
| 283 | * |
| 284 | * The caller must already have a reference. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 285 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 286 | static inline void css_get(struct cgroup_subsys_state *css) |
| 287 | { |
Tejun Heo | 3b514d2 | 2014-05-16 13:22:47 -0400 | [diff] [blame] | 288 | if (!(css->flags & CSS_NO_REF)) |
| 289 | percpu_ref_get(&css->refcnt); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 290 | } |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 291 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 292 | /** |
Johannes Weiner | e8ea14c | 2014-12-10 15:42:42 -0800 | [diff] [blame] | 293 | * css_get_many - obtain references on the specified css |
| 294 | * @css: target css |
| 295 | * @n: number of references to get |
| 296 | * |
| 297 | * The caller must already have a reference. |
| 298 | */ |
| 299 | static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) |
| 300 | { |
| 301 | if (!(css->flags & CSS_NO_REF)) |
| 302 | percpu_ref_get_many(&css->refcnt, n); |
| 303 | } |
| 304 | |
| 305 | /** |
Tejun Heo | 6f4524d | 2014-05-16 13:22:52 -0400 | [diff] [blame] | 306 | * css_tryget - try to obtain a reference on the specified css |
| 307 | * @css: target css |
| 308 | * |
| 309 | * Obtain a reference on @css unless it already has reached zero and is |
| 310 | * being released. This function doesn't care whether @css is on or |
| 311 | * offline. The caller naturally needs to ensure that @css is accessible |
| 312 | * but doesn't have to be holding a reference on it - IOW, RCU protected |
| 313 | * access is good enough for this function. Returns %true if a reference |
| 314 | * count was successfully obtained; %false otherwise. |
| 315 | */ |
| 316 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
| 317 | { |
| 318 | if (!(css->flags & CSS_NO_REF)) |
| 319 | return percpu_ref_tryget(&css->refcnt); |
| 320 | return true; |
| 321 | } |
| 322 | |
| 323 | /** |
Tejun Heo | ec903c0 | 2014-05-13 12:11:01 -0400 | [diff] [blame] | 324 | * css_tryget_online - try to obtain a reference on the specified css if online |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 325 | * @css: target css |
| 326 | * |
Tejun Heo | ec903c0 | 2014-05-13 12:11:01 -0400 | [diff] [blame] | 327 | * Obtain a reference on @css if it's online. The caller naturally needs |
| 328 | * to ensure that @css is accessible but doesn't have to be holding a |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 329 | * reference on it - IOW, RCU protected access is good enough for this |
| 330 | * function. Returns %true if a reference count was successfully obtained; |
| 331 | * %false otherwise. |
| 332 | */ |
Tejun Heo | ec903c0 | 2014-05-13 12:11:01 -0400 | [diff] [blame] | 333 | static inline bool css_tryget_online(struct cgroup_subsys_state *css) |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 334 | { |
Tejun Heo | 3b514d2 | 2014-05-16 13:22:47 -0400 | [diff] [blame] | 335 | if (!(css->flags & CSS_NO_REF)) |
| 336 | return percpu_ref_tryget_live(&css->refcnt); |
| 337 | return true; |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 338 | } |
| 339 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 340 | /** |
| 341 | * css_put - put a css reference |
| 342 | * @css: target css |
| 343 | * |
Tejun Heo | ec903c0 | 2014-05-13 12:11:01 -0400 | [diff] [blame] | 344 | * Put a reference obtained via css_get() and css_tryget_online(). |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 345 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 346 | static inline void css_put(struct cgroup_subsys_state *css) |
| 347 | { |
Tejun Heo | 3b514d2 | 2014-05-16 13:22:47 -0400 | [diff] [blame] | 348 | if (!(css->flags & CSS_NO_REF)) |
| 349 | percpu_ref_put(&css->refcnt); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 350 | } |
| 351 | |
Johannes Weiner | e8ea14c | 2014-12-10 15:42:42 -0800 | [diff] [blame] | 352 | /** |
| 353 | * css_put_many - put css references |
| 354 | * @css: target css |
| 355 | * @n: number of references to put |
| 356 | * |
| 357 | * Put references obtained via css_get() and css_tryget_online(). |
| 358 | */ |
| 359 | static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) |
| 360 | { |
| 361 | if (!(css->flags & CSS_NO_REF)) |
| 362 | percpu_ref_put_many(&css->refcnt, n); |
| 363 | } |
| 364 | |
Tejun Heo | 16af439 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 365 | static inline void cgroup_put(struct cgroup *cgrp) |
| 366 | { |
| 367 | css_put(&cgrp->self); |
| 368 | } |
| 369 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 370 | /** |
| 371 | * task_css_set_check - obtain a task's css_set with extra access conditions |
| 372 | * @task: the task to obtain css_set for |
| 373 | * @__c: extra condition expression to be passed to rcu_dereference_check() |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 374 | * |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 375 | * A task's css_set is RCU protected, initialized and exited while holding |
| 376 | * task_lock(), and can only be modified while holding both cgroup_mutex |
| 377 | * and task_lock() while the task is alive. This macro verifies that the |
| 378 | * caller is inside proper critical section and returns @task's css_set. |
| 379 | * |
| 380 | * The caller can also specify additional allowed conditions via @__c, such |
| 381 | * as locks used during the cgroup_subsys::attach() methods. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 382 | */ |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 383 | #ifdef CONFIG_PROVE_RCU |
| 384 | extern struct mutex cgroup_mutex; |
Tejun Heo | f0d9a5f | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 385 | extern spinlock_t css_set_lock; |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 386 | #define task_css_set_check(task, __c) \ |
| 387 | rcu_dereference_check((task)->cgroups, \ |
| 388 | lockdep_is_held(&cgroup_mutex) || \ |
Tejun Heo | f0d9a5f | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 389 | lockdep_is_held(&css_set_lock) || \ |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 390 | ((task)->flags & PF_EXITING) || (__c)) |
| 391 | #else |
| 392 | #define task_css_set_check(task, __c) \ |
| 393 | rcu_dereference((task)->cgroups) |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 394 | #endif |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 395 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 396 | /** |
| 397 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
| 398 | * @task: the target task |
| 399 | * @subsys_id: the target subsystem ID |
| 400 | * @__c: extra condition expression to be passed to rcu_dereference_check() |
| 401 | * |
| 402 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The |
| 403 | * synchronization rules are the same as task_css_set_check(). |
| 404 | */ |
| 405 | #define task_css_check(task, subsys_id, __c) \ |
| 406 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
| 407 | |
| 408 | /** |
| 409 | * task_css_set - obtain a task's css_set |
| 410 | * @task: the task to obtain css_set for |
| 411 | * |
| 412 | * See task_css_set_check(). |
| 413 | */ |
| 414 | static inline struct css_set *task_css_set(struct task_struct *task) |
| 415 | { |
| 416 | return task_css_set_check(task, false); |
| 417 | } |
| 418 | |
| 419 | /** |
| 420 | * task_css - obtain css for (task, subsys) |
| 421 | * @task: the target task |
| 422 | * @subsys_id: the target subsystem ID |
| 423 | * |
| 424 | * See task_css_check(). |
| 425 | */ |
| 426 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
| 427 | int subsys_id) |
| 428 | { |
| 429 | return task_css_check(task, subsys_id, false); |
| 430 | } |
| 431 | |
| 432 | /** |
Linus Torvalds | bbe179f | 2015-06-26 19:50:04 -0700 | [diff] [blame] | 433 | * task_get_css - find and get the css for (task, subsys) |
| 434 | * @task: the target task |
| 435 | * @subsys_id: the target subsystem ID |
| 436 | * |
| 437 | * Find the css for the (@task, @subsys_id) combination, increment a |
| 438 | * reference on and return it. This function is guaranteed to return a |
| 439 | * valid css. |
| 440 | */ |
| 441 | static inline struct cgroup_subsys_state * |
| 442 | task_get_css(struct task_struct *task, int subsys_id) |
| 443 | { |
| 444 | struct cgroup_subsys_state *css; |
| 445 | |
| 446 | rcu_read_lock(); |
| 447 | while (true) { |
| 448 | css = task_css(task, subsys_id); |
| 449 | if (likely(css_tryget_online(css))) |
| 450 | break; |
| 451 | cpu_relax(); |
| 452 | } |
| 453 | rcu_read_unlock(); |
| 454 | return css; |
| 455 | } |
| 456 | |
| 457 | /** |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 458 | * task_css_is_root - test whether a task belongs to the root css |
| 459 | * @task: the target task |
| 460 | * @subsys_id: the target subsystem ID |
| 461 | * |
| 462 | * Test whether @task belongs to the root css on the specified subsystem. |
| 463 | * May be invoked in any context. |
| 464 | */ |
| 465 | static inline bool task_css_is_root(struct task_struct *task, int subsys_id) |
| 466 | { |
| 467 | return task_css_check(task, subsys_id, true) == |
| 468 | init_css_set.subsys[subsys_id]; |
| 469 | } |
| 470 | |
| 471 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
| 472 | int subsys_id) |
| 473 | { |
| 474 | return task_css(task, subsys_id)->cgroup; |
| 475 | } |
Tejun Heo | a2dd424 | 2014-03-19 10:23:55 -0400 | [diff] [blame] | 476 | |
Tejun Heo | b11cfb5 | 2015-11-20 15:55:52 -0500 | [diff] [blame] | 477 | /** |
| 478 | * cgroup_is_descendant - test ancestry |
| 479 | * @cgrp: the cgroup to be tested |
| 480 | * @ancestor: possible ancestor of @cgrp |
| 481 | * |
| 482 | * Test whether @cgrp is a descendant of @ancestor. It also returns %true |
| 483 | * if @cgrp == @ancestor. This function is safe to call as long as @cgrp |
| 484 | * and @ancestor are accessible. |
| 485 | */ |
| 486 | static inline bool cgroup_is_descendant(struct cgroup *cgrp, |
| 487 | struct cgroup *ancestor) |
| 488 | { |
| 489 | if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) |
| 490 | return false; |
| 491 | return cgrp->ancestor_ids[ancestor->level] == ancestor->id; |
| 492 | } |
| 493 | |
Tejun Heo | 07bc356 | 2014-02-13 06:58:39 -0500 | [diff] [blame] | 494 | /* no synchronization, the result can only be used as a hint */ |
Tejun Heo | 27bd4db | 2015-10-15 16:41:50 -0400 | [diff] [blame] | 495 | static inline bool cgroup_is_populated(struct cgroup *cgrp) |
Tejun Heo | 07bc356 | 2014-02-13 06:58:39 -0500 | [diff] [blame] | 496 | { |
Tejun Heo | 27bd4db | 2015-10-15 16:41:50 -0400 | [diff] [blame] | 497 | return cgrp->populated_cnt; |
Tejun Heo | 07bc356 | 2014-02-13 06:58:39 -0500 | [diff] [blame] | 498 | } |
| 499 | |
Zefan Li | f29374b | 2014-09-19 16:29:31 +0800 | [diff] [blame] | 500 | /* returns ino associated with a cgroup */ |
Tejun Heo | b166492 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 501 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
| 502 | { |
Zefan Li | f29374b | 2014-09-19 16:29:31 +0800 | [diff] [blame] | 503 | return cgrp->kn->ino; |
Tejun Heo | b166492 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 504 | } |
| 505 | |
Tejun Heo | b416864 | 2014-05-13 12:16:21 -0400 | [diff] [blame] | 506 | /* cft/css accessors for cftype->write() operation */ |
| 507 | static inline struct cftype *of_cft(struct kernfs_open_file *of) |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 508 | { |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 509 | return of->kn->priv; |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 510 | } |
| 511 | |
Tejun Heo | b416864 | 2014-05-13 12:16:21 -0400 | [diff] [blame] | 512 | struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); |
| 513 | |
| 514 | /* cft/css accessors for cftype->seq_*() operations */ |
| 515 | static inline struct cftype *seq_cft(struct seq_file *seq) |
| 516 | { |
| 517 | return of_cft(seq->private); |
| 518 | } |
| 519 | |
| 520 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
| 521 | { |
| 522 | return of_css(seq->private); |
| 523 | } |
Tejun Heo | 59f5296 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 524 | |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 525 | /* |
| 526 | * Name / path handling functions. All are thin wrappers around the kernfs |
| 527 | * counterparts and can be called under any context. |
| 528 | */ |
| 529 | |
| 530 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
| 531 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 532 | return kernfs_name(cgrp->kn, buf, buflen); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 533 | } |
| 534 | |
| 535 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, |
| 536 | size_t buflen) |
| 537 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 538 | return kernfs_path(cgrp->kn, buf, buflen); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 539 | } |
| 540 | |
| 541 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
| 542 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 543 | pr_cont_kernfs_name(cgrp->kn); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 544 | } |
| 545 | |
| 546 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
| 547 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 548 | pr_cont_kernfs_path(cgrp->kn); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 549 | } |
| 550 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 551 | #else /* !CONFIG_CGROUPS */ |
| 552 | |
Tejun Heo | f3ba538 | 2015-01-06 12:02:46 -0500 | [diff] [blame] | 553 | struct cgroup_subsys_state; |
| 554 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 555 | static inline void css_put(struct cgroup_subsys_state *css) {} |
| 556 | static inline int cgroup_attach_task_all(struct task_struct *from, |
| 557 | struct task_struct *t) { return 0; } |
| 558 | static inline int cgroupstats_build(struct cgroupstats *stats, |
| 559 | struct dentry *dentry) { return -EINVAL; } |
| 560 | |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 561 | static inline void cgroup_fork(struct task_struct *p) {} |
Oleg Nesterov | b53202e | 2015-12-03 10:24:08 -0500 | [diff] [blame] | 562 | static inline int cgroup_can_fork(struct task_struct *p) { return 0; } |
| 563 | static inline void cgroup_cancel_fork(struct task_struct *p) {} |
| 564 | static inline void cgroup_post_fork(struct task_struct *p) {} |
Li Zefan | 1ec4183 | 2014-03-28 15:22:19 +0800 | [diff] [blame] | 565 | static inline void cgroup_exit(struct task_struct *p) {} |
Tejun Heo | 2e91fa7 | 2015-10-15 16:41:53 -0400 | [diff] [blame] | 566 | static inline void cgroup_free(struct task_struct *p) {} |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 567 | |
Tejun Heo | c326aa2 | 2015-05-13 16:24:16 -0400 | [diff] [blame] | 568 | static inline int cgroup_init_early(void) { return 0; } |
| 569 | static inline int cgroup_init(void) { return 0; } |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 570 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 571 | #endif /* !CONFIG_CGROUPS */ |
| 572 | |
Tejun Heo | bd1060a | 2015-12-07 17:38:53 -0500 | [diff] [blame] | 573 | /* |
| 574 | * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data |
| 575 | * definition in cgroup-defs.h. |
| 576 | */ |
| 577 | #ifdef CONFIG_SOCK_CGROUP_DATA |
| 578 | |
| 579 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) |
| 580 | extern spinlock_t cgroup_sk_update_lock; |
| 581 | #endif |
| 582 | |
| 583 | void cgroup_sk_alloc_disable(void); |
| 584 | void cgroup_sk_alloc(struct sock_cgroup_data *skcd); |
| 585 | void cgroup_sk_free(struct sock_cgroup_data *skcd); |
| 586 | |
| 587 | static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) |
| 588 | { |
| 589 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) |
| 590 | unsigned long v; |
| 591 | |
| 592 | /* |
| 593 | * @skcd->val is 64bit but the following is safe on 32bit too as we |
| 594 | * just need the lower ulong to be written and read atomically. |
| 595 | */ |
| 596 | v = READ_ONCE(skcd->val); |
| 597 | |
| 598 | if (v & 1) |
| 599 | return &cgrp_dfl_root.cgrp; |
| 600 | |
| 601 | return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp; |
| 602 | #else |
| 603 | return (struct cgroup *)(unsigned long)skcd->val; |
| 604 | #endif |
| 605 | } |
| 606 | |
| 607 | #else /* CONFIG_CGROUP_DATA */ |
| 608 | |
| 609 | static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} |
| 610 | static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} |
| 611 | |
| 612 | #endif /* CONFIG_CGROUP_DATA */ |
| 613 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 614 | #endif /* _LINUX_CGROUP_H */ |