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> |
| 14 | #include <linux/rcupdate.h> |
Tejun Heo | eb6fd50 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 15 | #include <linux/rculist.h> |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 16 | #include <linux/cgroupstats.h> |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 17 | #include <linux/rwsem.h> |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 18 | #include <linux/idr.h> |
Tejun Heo | 48ddbe1 | 2012-04-01 12:09:56 -0700 | [diff] [blame] | 19 | #include <linux/workqueue.h> |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 20 | #include <linux/fs.h> |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 21 | #include <linux/percpu-refcount.h> |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 22 | #include <linux/seq_file.h> |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 23 | #include <linux/kernfs.h> |
Tejun Heo | f8f22e5 | 2014-04-23 11:13:16 -0400 | [diff] [blame^] | 24 | #include <linux/wait.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 25 | |
| 26 | #ifdef CONFIG_CGROUPS |
| 27 | |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 28 | struct cgroup_root; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 29 | struct cgroup_subsys; |
| 30 | struct inode; |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 31 | struct cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 32 | |
| 33 | extern int cgroup_init_early(void); |
| 34 | extern int cgroup_init(void); |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 35 | extern void cgroup_fork(struct task_struct *p); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 36 | extern void cgroup_post_fork(struct task_struct *p); |
Li Zefan | 1ec4183 | 2014-03-28 15:22:19 +0800 | [diff] [blame] | 37 | extern void cgroup_exit(struct task_struct *p); |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 38 | extern int cgroupstats_build(struct cgroupstats *stats, |
| 39 | struct dentry *dentry); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 40 | |
Al Viro | 8d8b97b | 2013-04-19 23:11:24 -0400 | [diff] [blame] | 41 | extern int proc_cgroup_show(struct seq_file *, void *); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 42 | |
Tejun Heo | 3ed80a6 | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 43 | /* define the enumeration of all cgroup subsystems */ |
Tejun Heo | 073219e | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 44 | #define SUBSYS(_x) _x ## _cgrp_id, |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 45 | enum cgroup_subsys_id { |
| 46 | #include <linux/cgroup_subsys.h> |
Daniel Wagner | a6f0029 | 2012-09-12 16:12:08 +0200 | [diff] [blame] | 47 | CGROUP_SUBSYS_COUNT, |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 48 | }; |
| 49 | #undef SUBSYS |
| 50 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 51 | /* Per-subsystem/per-cgroup state maintained by the system. */ |
| 52 | struct cgroup_subsys_state { |
Tejun Heo | 72c97e5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 53 | /* the cgroup that this css is attached to */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 54 | struct cgroup *cgroup; |
| 55 | |
Tejun Heo | 72c97e5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 56 | /* the cgroup subsystem that this css is attached to */ |
| 57 | struct cgroup_subsys *ss; |
| 58 | |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 59 | /* reference count - access via css_[try]get() and css_put() */ |
| 60 | struct percpu_ref refcnt; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 61 | |
Tejun Heo | 0ae78e0 | 2013-08-13 11:01:54 -0400 | [diff] [blame] | 62 | /* the parent css */ |
| 63 | struct cgroup_subsys_state *parent; |
| 64 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 65 | unsigned long flags; |
Tejun Heo | 48ddbe1 | 2012-04-01 12:09:56 -0700 | [diff] [blame] | 66 | |
Tejun Heo | 0c21ead | 2013-08-13 20:22:51 -0400 | [diff] [blame] | 67 | /* percpu_ref killing and RCU release */ |
| 68 | struct rcu_head rcu_head; |
Tejun Heo | 35ef10d | 2013-08-13 11:01:54 -0400 | [diff] [blame] | 69 | struct work_struct destroy_work; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 70 | }; |
| 71 | |
| 72 | /* bits in struct cgroup_subsys_state flags field */ |
| 73 | enum { |
Tejun Heo | 38b53ab | 2012-11-19 08:13:36 -0800 | [diff] [blame] | 74 | CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */ |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 75 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 76 | }; |
| 77 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 78 | /** |
| 79 | * css_get - obtain a reference on the specified css |
| 80 | * @css: target css |
| 81 | * |
| 82 | * The caller must already have a reference. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 83 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 84 | static inline void css_get(struct cgroup_subsys_state *css) |
| 85 | { |
| 86 | /* We don't need to reference count the root state */ |
Tejun Heo | 38b53ab | 2012-11-19 08:13:36 -0800 | [diff] [blame] | 87 | if (!(css->flags & CSS_ROOT)) |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 88 | percpu_ref_get(&css->refcnt); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 89 | } |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 90 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 91 | /** |
| 92 | * css_tryget - try to obtain a reference on the specified css |
| 93 | * @css: target css |
| 94 | * |
| 95 | * Obtain a reference on @css if it's alive. The caller naturally needs to |
| 96 | * ensure that @css is accessible but doesn't have to be holding a |
| 97 | * reference on it - IOW, RCU protected access is good enough for this |
| 98 | * function. Returns %true if a reference count was successfully obtained; |
| 99 | * %false otherwise. |
| 100 | */ |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 101 | static inline bool css_tryget(struct cgroup_subsys_state *css) |
| 102 | { |
Tejun Heo | 38b53ab | 2012-11-19 08:13:36 -0800 | [diff] [blame] | 103 | if (css->flags & CSS_ROOT) |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 104 | return true; |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 105 | return percpu_ref_tryget(&css->refcnt); |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 106 | } |
| 107 | |
Tejun Heo | 5de0107 | 2013-06-12 21:04:52 -0700 | [diff] [blame] | 108 | /** |
| 109 | * css_put - put a css reference |
| 110 | * @css: target css |
| 111 | * |
| 112 | * Put a reference obtained via css_get() and css_tryget(). |
| 113 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 114 | static inline void css_put(struct cgroup_subsys_state *css) |
| 115 | { |
Tejun Heo | 38b53ab | 2012-11-19 08:13:36 -0800 | [diff] [blame] | 116 | if (!(css->flags & CSS_ROOT)) |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 117 | percpu_ref_put(&css->refcnt); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 118 | } |
| 119 | |
Paul Menage | 3116f0e | 2008-04-29 01:00:04 -0700 | [diff] [blame] | 120 | /* bits in struct cgroup flags field */ |
| 121 | enum { |
| 122 | /* Control Group is dead */ |
Tejun Heo | 54766d4 | 2013-06-12 21:04:53 -0700 | [diff] [blame] | 123 | CGRP_DEAD, |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 124 | /* |
| 125 | * Control Group has previously had a child cgroup or a task, |
| 126 | * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) |
| 127 | */ |
Paul Menage | 3116f0e | 2008-04-29 01:00:04 -0700 | [diff] [blame] | 128 | CGRP_RELEASABLE, |
| 129 | /* Control Group requires release notifications to userspace */ |
| 130 | CGRP_NOTIFY_ON_RELEASE, |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 131 | /* |
Tejun Heo | 2260e7f | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 132 | * Clone the parent's configuration when creating a new child |
| 133 | * cpuset cgroup. For historical reasons, this option can be |
| 134 | * specified at mount time and thus is implemented here. |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 135 | */ |
Tejun Heo | 2260e7f | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 136 | CGRP_CPUSET_CLONE_CHILDREN, |
Tejun Heo | 873fe09 | 2013-04-14 20:15:26 -0700 | [diff] [blame] | 137 | /* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */ |
| 138 | CGRP_SANE_BEHAVIOR, |
Paul Menage | 3116f0e | 2008-04-29 01:00:04 -0700 | [diff] [blame] | 139 | }; |
| 140 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 141 | struct cgroup { |
| 142 | unsigned long flags; /* "unsigned long" so bitops work */ |
| 143 | |
Li Zefan | b414dc0 | 2013-07-31 09:51:06 +0800 | [diff] [blame] | 144 | /* |
| 145 | * idr allocated in-hierarchy ID. |
| 146 | * |
| 147 | * The ID of the root cgroup is always 0, and a new cgroup |
| 148 | * will be assigned with a smallest available ID. |
Li Zefan | 0ab02ca | 2014-02-11 16:05:46 +0800 | [diff] [blame] | 149 | * |
| 150 | * Allocating/Removing ID must be protected by cgroup_mutex. |
Li Zefan | b414dc0 | 2013-07-31 09:51:06 +0800 | [diff] [blame] | 151 | */ |
| 152 | int id; |
Tejun Heo | 0a950f6 | 2012-11-19 09:02:12 -0800 | [diff] [blame] | 153 | |
Tejun Heo | f20104d | 2013-08-13 20:22:50 -0400 | [diff] [blame] | 154 | /* the number of attached css's */ |
| 155 | int nr_css; |
| 156 | |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 157 | atomic_t refcnt; |
| 158 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 159 | /* |
| 160 | * We link our 'sibling' struct into our parent's 'children'. |
| 161 | * Our children link their 'sibling' into our 'children'. |
| 162 | */ |
| 163 | struct list_head sibling; /* my parent's children */ |
| 164 | struct list_head children; /* my children */ |
| 165 | |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 166 | struct cgroup *parent; /* my parent */ |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 167 | struct kernfs_node *kn; /* cgroup kernfs entry */ |
Tejun Heo | f8f22e5 | 2014-04-23 11:13:16 -0400 | [diff] [blame^] | 168 | struct kernfs_node *control_kn; /* kn for "cgroup.subtree_control" */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 169 | |
Li Zefan | 65dff75 | 2013-03-01 15:01:56 +0800 | [diff] [blame] | 170 | /* |
Tejun Heo | 53fa526 | 2013-05-24 10:55:38 +0900 | [diff] [blame] | 171 | * Monotonically increasing unique serial number which defines a |
| 172 | * uniform order among all cgroups. It's guaranteed that all |
| 173 | * ->children lists are in the ascending order of ->serial_nr. |
| 174 | * It's used to allow interrupting and resuming iterations. |
| 175 | */ |
| 176 | u64 serial_nr; |
| 177 | |
Tejun Heo | f392e51 | 2014-04-23 11:13:14 -0400 | [diff] [blame] | 178 | /* the bitmask of subsystems enabled on the child cgroups */ |
| 179 | unsigned long child_subsys_mask; |
Tejun Heo | 9441962 | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 180 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 181 | /* Private pointers for each registered subsystem */ |
Tejun Heo | 73e80ed | 2013-08-13 11:01:55 -0400 | [diff] [blame] | 182 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 183 | |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 184 | struct cgroup_root *root; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 185 | |
| 186 | /* |
Tejun Heo | 69d0206 | 2013-06-12 21:04:50 -0700 | [diff] [blame] | 187 | * List of cgrp_cset_links pointing at css_sets with tasks in this |
| 188 | * cgroup. Protected by css_set_lock. |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 189 | */ |
Tejun Heo | 69d0206 | 2013-06-12 21:04:50 -0700 | [diff] [blame] | 190 | struct list_head cset_links; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 191 | |
| 192 | /* |
Tejun Heo | 2d8f243 | 2014-04-23 11:13:15 -0400 | [diff] [blame] | 193 | * On the default hierarchy, a css_set for a cgroup with some |
| 194 | * susbsys disabled will point to css's which are associated with |
| 195 | * the closest ancestor which has the subsys enabled. The |
| 196 | * following lists all css_sets which point to this cgroup's css |
| 197 | * for the given subsystem. |
| 198 | */ |
| 199 | struct list_head e_csets[CGROUP_SUBSYS_COUNT]; |
| 200 | |
| 201 | /* |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 202 | * Linked list running through all cgroups that can |
| 203 | * potentially be reaped by the release agent. Protected by |
| 204 | * release_list_lock |
| 205 | */ |
| 206 | struct list_head release_list; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 207 | |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 208 | /* |
| 209 | * list of pidlists, up to two for each namespace (one for procs, one |
| 210 | * for tasks); created on demand. |
| 211 | */ |
| 212 | struct list_head pidlists; |
| 213 | struct mutex pidlist_mutex; |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 214 | |
Tejun Heo | 67f4c36 | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 215 | /* dummy css with NULL ->ss, points back to this cgroup */ |
| 216 | struct cgroup_subsys_state dummy_css; |
| 217 | |
Tejun Heo | d3daf28 | 2013-06-13 19:39:16 -0700 | [diff] [blame] | 218 | /* For css percpu_ref killing and RCU-protected deletion */ |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 219 | struct rcu_head rcu_head; |
Tejun Heo | ea15f8c | 2013-06-13 19:27:42 -0700 | [diff] [blame] | 220 | struct work_struct destroy_work; |
Tejun Heo | f8f22e5 | 2014-04-23 11:13:16 -0400 | [diff] [blame^] | 221 | |
| 222 | /* used to wait for offlining of csses */ |
| 223 | wait_queue_head_t offline_waitq; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 224 | }; |
| 225 | |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 226 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
| 227 | |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 228 | /* cgroup_root->flags */ |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 229 | enum { |
Tejun Heo | 873fe09 | 2013-04-14 20:15:26 -0700 | [diff] [blame] | 230 | /* |
| 231 | * Unfortunately, cgroup core and various controllers are riddled |
| 232 | * with idiosyncrasies and pointless options. The following flag, |
| 233 | * when set, will force sane behavior - some options are forced on, |
| 234 | * others are disallowed, and some controllers will change their |
| 235 | * hierarchical or other behaviors. |
| 236 | * |
| 237 | * The set of behaviors affected by this flag are still being |
| 238 | * determined and developed and the mount option for this flag is |
| 239 | * prefixed with __DEVEL__. The prefix will be dropped once we |
| 240 | * reach the point where all behaviors are compatible with the |
| 241 | * planned unified hierarchy, which will automatically turn on this |
| 242 | * flag. |
| 243 | * |
| 244 | * The followings are the behaviors currently affected this flag. |
| 245 | * |
Tejun Heo | d3ba07c | 2014-02-13 06:58:38 -0500 | [diff] [blame] | 246 | * - Mount options "noprefix", "xattr", "clone_children", |
| 247 | * "release_agent" and "name" are disallowed. |
Tejun Heo | 873fe09 | 2013-04-14 20:15:26 -0700 | [diff] [blame] | 248 | * |
| 249 | * - When mounting an existing superblock, mount options should |
| 250 | * match. |
| 251 | * |
| 252 | * - Remount is disallowed. |
| 253 | * |
Linus Torvalds | 0b0585c | 2013-07-02 20:04:25 -0700 | [diff] [blame] | 254 | * - rename(2) is disallowed. |
| 255 | * |
Tejun Heo | f63674f | 2013-06-13 19:58:38 -0700 | [diff] [blame] | 256 | * - "tasks" is removed. Everything should be at process |
| 257 | * granularity. Use "cgroup.procs" instead. |
| 258 | * |
Tejun Heo | afb2bc1 | 2013-11-29 10:42:59 -0500 | [diff] [blame] | 259 | * - "cgroup.procs" is not sorted. pids will be unique unless they |
| 260 | * got recycled inbetween reads. |
| 261 | * |
Tejun Heo | f63674f | 2013-06-13 19:58:38 -0700 | [diff] [blame] | 262 | * - "release_agent" and "notify_on_release" are removed. |
| 263 | * Replacement notification mechanism will be implemented. |
| 264 | * |
Tejun Heo | d3ba07c | 2014-02-13 06:58:38 -0500 | [diff] [blame] | 265 | * - "cgroup.clone_children" is removed. |
Tejun Heo | 86bf4b6 | 2014-02-12 09:29:48 -0500 | [diff] [blame] | 266 | * |
Tejun Heo | a2dd424 | 2014-03-19 10:23:55 -0400 | [diff] [blame] | 267 | * - If mount is requested with sane_behavior but without any |
| 268 | * subsystem, the default unified hierarchy is mounted. |
| 269 | * |
Li Zefan | 5c5cc62 | 2013-06-09 17:16:29 +0800 | [diff] [blame] | 270 | * - cpuset: tasks will be kept in empty cpusets when hotplug happens |
| 271 | * and take masks of ancestors with non-empty cpus/mems, instead of |
| 272 | * being moved to an ancestor. |
| 273 | * |
Li Zefan | 88fa523 | 2013-06-09 17:16:46 +0800 | [diff] [blame] | 274 | * - cpuset: a task can be moved into an empty cpuset, and again it |
| 275 | * takes masks of ancestors. |
Tejun Heo | 6db8e85 | 2013-06-14 11:18:22 -0700 | [diff] [blame] | 276 | * |
Tejun Heo | f00baae | 2013-04-15 13:41:15 -0700 | [diff] [blame] | 277 | * - memcg: use_hierarchy is on by default and the cgroup file for |
| 278 | * the flag is not created. |
| 279 | * |
Tejun Heo | 9138125 | 2013-05-14 13:52:38 -0700 | [diff] [blame] | 280 | * - blkcg: blk-throttle becomes properly hierarchical. |
Tejun Heo | 873fe09 | 2013-04-14 20:15:26 -0700 | [diff] [blame] | 281 | */ |
| 282 | CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), |
| 283 | |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 284 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
| 285 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ |
Tejun Heo | 0ce6cba | 2013-06-27 19:37:26 -0700 | [diff] [blame] | 286 | |
| 287 | /* mount options live below bit 16 */ |
| 288 | CGRP_ROOT_OPTION_MASK = (1 << 16) - 1, |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 289 | }; |
| 290 | |
| 291 | /* |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 292 | * A cgroup_root represents the root of a cgroup hierarchy, and may be |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 293 | * associated with a kernfs_root to form an active hierarchy. This is |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 294 | * internal to cgroup core. Don't access directly from controllers. |
| 295 | */ |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 296 | struct cgroup_root { |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 297 | struct kernfs_root *kf_root; |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 298 | |
Tejun Heo | f392e51 | 2014-04-23 11:13:14 -0400 | [diff] [blame] | 299 | /* The bitmask of subsystems attached to this hierarchy */ |
| 300 | unsigned long subsys_mask; |
| 301 | |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 302 | /* Unique id for this hierarchy. */ |
| 303 | int hierarchy_id; |
| 304 | |
Tejun Heo | 776f02f | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 305 | /* The root cgroup. Root is destroyed on its release. */ |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 306 | struct cgroup cgrp; |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 307 | |
Tejun Heo | 3c9c825 | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 308 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
| 309 | atomic_t nr_cgrps; |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 310 | |
| 311 | /* A list running through the active hierarchies */ |
| 312 | struct list_head root_list; |
| 313 | |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 314 | /* Hierarchy-specific flags */ |
| 315 | unsigned long flags; |
| 316 | |
| 317 | /* IDs for cgroups in this hierarchy */ |
Li Zefan | 4e96ee8e | 2013-07-31 09:50:50 +0800 | [diff] [blame] | 318 | struct idr cgroup_idr; |
Tejun Heo | 25a7e68 | 2013-04-14 20:15:25 -0700 | [diff] [blame] | 319 | |
| 320 | /* The path to use for release notifications. */ |
| 321 | char release_agent_path[PATH_MAX]; |
| 322 | |
| 323 | /* The name for this hierarchy - may be empty */ |
| 324 | char name[MAX_CGROUP_ROOT_NAMELEN]; |
| 325 | }; |
| 326 | |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 327 | /* |
| 328 | * A css_set is a structure holding pointers to a set of |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 329 | * cgroup_subsys_state objects. This saves space in the task struct |
| 330 | * object and speeds up fork()/exit(), since a single inc/dec and a |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 331 | * list_add()/del() can bump the reference count on the entire cgroup |
| 332 | * set for a task. |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 333 | */ |
| 334 | |
| 335 | struct css_set { |
| 336 | |
| 337 | /* Reference count */ |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 338 | atomic_t refcount; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 339 | |
| 340 | /* |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 341 | * List running through all cgroup groups in the same hash |
| 342 | * slot. Protected by css_set_lock |
| 343 | */ |
| 344 | struct hlist_node hlist; |
| 345 | |
| 346 | /* |
Tejun Heo | c756112 | 2014-02-25 10:04:01 -0500 | [diff] [blame] | 347 | * Lists running through all tasks using this cgroup group. |
| 348 | * mg_tasks lists tasks which belong to this cset but are in the |
| 349 | * process of being migrated out or in. Protected by |
| 350 | * css_set_rwsem, but, during migration, once tasks are moved to |
| 351 | * mg_tasks, it can be read safely while holding cgroup_mutex. |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 352 | */ |
| 353 | struct list_head tasks; |
Tejun Heo | c756112 | 2014-02-25 10:04:01 -0500 | [diff] [blame] | 354 | struct list_head mg_tasks; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 355 | |
| 356 | /* |
Tejun Heo | 69d0206 | 2013-06-12 21:04:50 -0700 | [diff] [blame] | 357 | * List of cgrp_cset_links pointing at cgroups referenced from this |
| 358 | * css_set. Protected by css_set_lock. |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 359 | */ |
Tejun Heo | 69d0206 | 2013-06-12 21:04:50 -0700 | [diff] [blame] | 360 | struct list_head cgrp_links; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 361 | |
Tejun Heo | 6803c00 | 2014-04-23 11:13:16 -0400 | [diff] [blame] | 362 | /* the default cgroup associated with this css_set */ |
| 363 | struct cgroup *dfl_cgrp; |
| 364 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 365 | /* |
Tejun Heo | 3ed80a6 | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 366 | * Set of subsystem states, one for each subsystem. This array is |
| 367 | * immutable after creation apart from the init_css_set during |
| 368 | * subsystem registration (at boot time). |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 369 | */ |
| 370 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
Ben Blum | c378369 | 2009-09-23 15:56:29 -0700 | [diff] [blame] | 371 | |
Tejun Heo | b3dc094 | 2014-02-25 10:04:01 -0500 | [diff] [blame] | 372 | /* |
| 373 | * List of csets participating in the on-going migration either as |
| 374 | * source or destination. Protected by cgroup_mutex. |
| 375 | */ |
Tejun Heo | 1958d2d | 2014-02-25 10:04:03 -0500 | [diff] [blame] | 376 | struct list_head mg_preload_node; |
Tejun Heo | b3dc094 | 2014-02-25 10:04:01 -0500 | [diff] [blame] | 377 | struct list_head mg_node; |
| 378 | |
| 379 | /* |
| 380 | * If this cset is acting as the source of migration the following |
| 381 | * two fields are set. mg_src_cgrp is the source cgroup of the |
| 382 | * on-going migration and mg_dst_cset is the destination cset the |
| 383 | * target tasks on this cset should be migrated to. Protected by |
| 384 | * cgroup_mutex. |
| 385 | */ |
| 386 | struct cgroup *mg_src_cgrp; |
| 387 | struct css_set *mg_dst_cset; |
| 388 | |
Tejun Heo | 2d8f243 | 2014-04-23 11:13:15 -0400 | [diff] [blame] | 389 | /* |
| 390 | * On the default hierarhcy, ->subsys[ssid] may point to a css |
| 391 | * attached to an ancestor instead of the cgroup this css_set is |
| 392 | * associated with. The following node is anchored at |
| 393 | * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to |
| 394 | * iterate through all css's attached to a given cgroup. |
| 395 | */ |
| 396 | struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; |
| 397 | |
Ben Blum | c378369 | 2009-09-23 15:56:29 -0700 | [diff] [blame] | 398 | /* For RCU-protected deletion */ |
| 399 | struct rcu_head rcu_head; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 400 | }; |
| 401 | |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 402 | /* |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 403 | * struct cftype: handler definitions for cgroup control files |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 404 | * |
| 405 | * When reading/writing to a file: |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 406 | * - the cgroup to use is file->f_dentry->d_parent->d_fsdata |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 407 | * - the 'cftype' of the file is file->f_dentry->d_fsdata |
| 408 | */ |
| 409 | |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 410 | /* cftype->flags */ |
Tejun Heo | 02c402d | 2013-06-24 15:21:47 -0700 | [diff] [blame] | 411 | enum { |
Li Zefan | 6f4b7e6 | 2013-07-31 16:18:36 +0800 | [diff] [blame] | 412 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ |
| 413 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ |
Tejun Heo | 02c402d | 2013-06-24 15:21:47 -0700 | [diff] [blame] | 414 | CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */ |
Tejun Heo | 9fa4db3 | 2013-08-26 18:40:56 -0400 | [diff] [blame] | 415 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ |
Tejun Heo | 8cbbf2c | 2014-03-19 10:23:55 -0400 | [diff] [blame] | 416 | CFTYPE_ONLY_ON_DFL = (1 << 4), /* only on default hierarchy */ |
Tejun Heo | 02c402d | 2013-06-24 15:21:47 -0700 | [diff] [blame] | 417 | }; |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 418 | |
| 419 | #define MAX_CFTYPE_NAME 64 |
| 420 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 421 | struct cftype { |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 422 | /* |
| 423 | * By convention, the name should begin with the name of the |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 424 | * subsystem, followed by a period. Zero length string indicates |
| 425 | * end of cftype array. |
Paul Menage | d20a390 | 2009-04-02 16:57:22 -0700 | [diff] [blame] | 426 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 427 | char name[MAX_CFTYPE_NAME]; |
| 428 | int private; |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 429 | /* |
| 430 | * If not 0, file mode is set to this value, otherwise it will |
| 431 | * be figured out automatically |
| 432 | */ |
Al Viro | a5e7ed3 | 2011-07-26 01:55:55 -0400 | [diff] [blame] | 433 | umode_t mode; |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 434 | |
| 435 | /* |
Tejun Heo | 5f46990 | 2014-02-11 11:52:48 -0500 | [diff] [blame] | 436 | * The maximum length of string, excluding trailing nul, that can |
| 437 | * be passed to write_string. If < PAGE_SIZE-1, PAGE_SIZE-1 is |
| 438 | * assumed. |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 439 | */ |
| 440 | size_t max_write_len; |
| 441 | |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 442 | /* CFTYPE_* flags */ |
| 443 | unsigned int flags; |
| 444 | |
Tejun Heo | 2bb566c | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 445 | /* |
Tejun Heo | 0adb070 | 2014-02-12 09:29:48 -0500 | [diff] [blame] | 446 | * Fields used for internal bookkeeping. Initialized automatically |
| 447 | * during registration. |
Tejun Heo | 2bb566c | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 448 | */ |
Tejun Heo | 0adb070 | 2014-02-12 09:29:48 -0500 | [diff] [blame] | 449 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ |
| 450 | struct list_head node; /* anchored at ss->cfts */ |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 451 | struct kernfs_ops *kf_ops; |
| 452 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 453 | /* |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 454 | * read_u64() is a shortcut for the common case of returning a |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 455 | * single integer. Use it in place of read() |
| 456 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 457 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 458 | /* |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 459 | * read_s64() is a signed version of read_u64() |
| 460 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 461 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); |
Tejun Heo | 2da8ca8 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 462 | |
| 463 | /* generic seq_file read interface */ |
| 464 | int (*seq_show)(struct seq_file *sf, void *v); |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 465 | |
Tejun Heo | 6612f05 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 466 | /* optional ops, implement all or none */ |
| 467 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); |
| 468 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); |
| 469 | void (*seq_stop)(struct seq_file *sf, void *v); |
| 470 | |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 471 | /* |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 472 | * write_u64() is a shortcut for the common case of accepting |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 473 | * a single integer (as parsed by simple_strtoull) from |
| 474 | * userspace. Use in place of write(); return 0 or error. |
| 475 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 476 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, |
| 477 | u64 val); |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 478 | /* |
| 479 | * write_s64() is a signed version of write_u64() |
| 480 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 481 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, |
| 482 | s64 val); |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 483 | |
Pavel Emelyanov | d447ea2 | 2008-04-29 01:00:08 -0700 | [diff] [blame] | 484 | /* |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 485 | * write_string() is passed a nul-terminated kernelspace |
| 486 | * buffer of maximum length determined by max_write_len. |
| 487 | * Returns 0 or -ve error code. |
| 488 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 489 | int (*write_string)(struct cgroup_subsys_state *css, struct cftype *cft, |
Tejun Heo | 4d3bb51 | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 490 | char *buffer); |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 491 | /* |
Pavel Emelyanov | d447ea2 | 2008-04-29 01:00:08 -0700 | [diff] [blame] | 492 | * trigger() callback can be used to get some kick from the |
| 493 | * userspace, when the actual string written is not important |
| 494 | * at all. The private field can be used to determine the |
| 495 | * kick type for multiplexing. |
| 496 | */ |
Tejun Heo | 182446d | 2013-08-08 20:11:24 -0400 | [diff] [blame] | 497 | int (*trigger)(struct cgroup_subsys_state *css, unsigned int event); |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 498 | |
| 499 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 500 | struct lock_class_key lockdep_key; |
| 501 | #endif |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 502 | }; |
| 503 | |
Tejun Heo | a2dd424 | 2014-03-19 10:23:55 -0400 | [diff] [blame] | 504 | extern struct cgroup_root cgrp_dfl_root; |
| 505 | |
| 506 | static inline bool cgroup_on_dfl(const struct cgroup *cgrp) |
| 507 | { |
| 508 | return cgrp->root == &cgrp_dfl_root; |
| 509 | } |
| 510 | |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 511 | /* |
Tejun Heo | 873fe09 | 2013-04-14 20:15:26 -0700 | [diff] [blame] | 512 | * See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This |
| 513 | * function can be called as long as @cgrp is accessible. |
| 514 | */ |
| 515 | static inline bool cgroup_sane_behavior(const struct cgroup *cgrp) |
| 516 | { |
| 517 | return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR; |
| 518 | } |
| 519 | |
Tejun Heo | 07bc356 | 2014-02-13 06:58:39 -0500 | [diff] [blame] | 520 | /* no synchronization, the result can only be used as a hint */ |
| 521 | static inline bool cgroup_has_tasks(struct cgroup *cgrp) |
| 522 | { |
| 523 | return !list_empty(&cgrp->cset_links); |
| 524 | } |
| 525 | |
Tejun Heo | b166492 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 526 | /* returns ino associated with a cgroup, 0 indicates unmounted root */ |
| 527 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
| 528 | { |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 529 | if (cgrp->kn) |
| 530 | return cgrp->kn->ino; |
Tejun Heo | b166492 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 531 | else |
| 532 | return 0; |
| 533 | } |
| 534 | |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 535 | static inline struct cftype *seq_cft(struct seq_file *seq) |
| 536 | { |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 537 | struct kernfs_open_file *of = seq->private; |
| 538 | |
| 539 | return of->kn->priv; |
Tejun Heo | 7da1127 | 2013-12-05 12:28:04 -0500 | [diff] [blame] | 540 | } |
| 541 | |
Tejun Heo | 59f5296 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 542 | struct cgroup_subsys_state *seq_css(struct seq_file *seq); |
| 543 | |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 544 | /* |
| 545 | * Name / path handling functions. All are thin wrappers around the kernfs |
| 546 | * counterparts and can be called under any context. |
| 547 | */ |
| 548 | |
| 549 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
| 550 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 551 | return kernfs_name(cgrp->kn, buf, buflen); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 552 | } |
| 553 | |
| 554 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, |
| 555 | size_t buflen) |
| 556 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 557 | return kernfs_path(cgrp->kn, buf, buflen); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 558 | } |
| 559 | |
| 560 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
| 561 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 562 | pr_cont_kernfs_name(cgrp->kn); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 563 | } |
| 564 | |
| 565 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
| 566 | { |
Tejun Heo | fdce6bf | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 567 | pr_cont_kernfs_path(cgrp->kn); |
Tejun Heo | e61734c | 2014-02-12 09:29:50 -0500 | [diff] [blame] | 568 | } |
| 569 | |
| 570 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); |
| 571 | |
Aristeu Rozanski | 03b1cde | 2012-08-23 16:53:30 -0400 | [diff] [blame] | 572 | int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); |
Tejun Heo | 2bb566c | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 573 | int cgroup_rm_cftypes(struct cftype *cfts); |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 574 | |
Li Zefan | 78574cf | 2013-04-08 19:00:38 -0700 | [diff] [blame] | 575 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 576 | |
Thadeu Lima de Souza Cascardo | 21acb9c | 2009-02-04 10:12:08 +0100 | [diff] [blame] | 577 | /* |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 578 | * Control Group taskset, used to pass around set of tasks to cgroup_subsys |
| 579 | * methods. |
| 580 | */ |
| 581 | struct cgroup_taskset; |
| 582 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); |
| 583 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 584 | |
| 585 | /** |
| 586 | * cgroup_taskset_for_each - iterate cgroup_taskset |
| 587 | * @task: the loop cursor |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 588 | * @tset: taskset to iterate |
| 589 | */ |
Tejun Heo | 924f0d9 | 2014-02-13 06:58:41 -0500 | [diff] [blame] | 590 | #define cgroup_taskset_for_each(task, tset) \ |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 591 | for ((task) = cgroup_taskset_first((tset)); (task); \ |
Tejun Heo | 924f0d9 | 2014-02-13 06:58:41 -0500 | [diff] [blame] | 592 | (task) = cgroup_taskset_next((tset))) |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 593 | |
| 594 | /* |
Thadeu Lima de Souza Cascardo | 21acb9c | 2009-02-04 10:12:08 +0100 | [diff] [blame] | 595 | * Control Group subsystem type. |
| 596 | * See Documentation/cgroups/cgroups.txt for details |
| 597 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 598 | |
| 599 | struct cgroup_subsys { |
Tejun Heo | eb95419 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 600 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); |
| 601 | int (*css_online)(struct cgroup_subsys_state *css); |
| 602 | void (*css_offline)(struct cgroup_subsys_state *css); |
| 603 | void (*css_free)(struct cgroup_subsys_state *css); |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 604 | |
Tejun Heo | eb95419 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 605 | int (*can_attach)(struct cgroup_subsys_state *css, |
| 606 | struct cgroup_taskset *tset); |
| 607 | void (*cancel_attach)(struct cgroup_subsys_state *css, |
| 608 | struct cgroup_taskset *tset); |
| 609 | void (*attach)(struct cgroup_subsys_state *css, |
| 610 | struct cgroup_taskset *tset); |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 611 | void (*fork)(struct task_struct *task); |
Tejun Heo | eb95419 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 612 | void (*exit)(struct cgroup_subsys_state *css, |
| 613 | struct cgroup_subsys_state *old_css, |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 614 | struct task_struct *task); |
Tejun Heo | eb95419 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 615 | void (*bind)(struct cgroup_subsys_state *root_css); |
Hugh Dickins | e599137 | 2009-01-06 14:39:22 -0800 | [diff] [blame] | 616 | |
Paul Menage | 8bab8dd | 2008-04-04 14:29:57 -0700 | [diff] [blame] | 617 | int disabled; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 618 | int early_init; |
Tejun Heo | 48ddbe1 | 2012-04-01 12:09:56 -0700 | [diff] [blame] | 619 | |
| 620 | /* |
Tejun Heo | 8c7f6ed | 2012-09-13 12:20:58 -0700 | [diff] [blame] | 621 | * If %false, this subsystem is properly hierarchical - |
| 622 | * configuration, resource accounting and restriction on a parent |
| 623 | * cgroup cover those of its children. If %true, hierarchy support |
| 624 | * is broken in some ways - some subsystems ignore hierarchy |
| 625 | * completely while others are only implemented half-way. |
| 626 | * |
| 627 | * It's now disallowed to create nested cgroups if the subsystem is |
| 628 | * broken and cgroup core will emit a warning message on such |
| 629 | * cases. Eventually, all subsystems will be made properly |
| 630 | * hierarchical and this will go away. |
| 631 | */ |
| 632 | bool broken_hierarchy; |
| 633 | bool warned_broken_hierarchy; |
| 634 | |
Tejun Heo | 073219e | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 635 | /* the following two fields are initialized automtically during boot */ |
Tejun Heo | aec2502 | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 636 | int id; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 637 | #define MAX_CGROUP_TYPE_NAMELEN 32 |
| 638 | const char *name; |
| 639 | |
Tejun Heo | b85d204 | 2013-12-06 15:11:57 -0500 | [diff] [blame] | 640 | /* link to parent, protected by cgroup_lock() */ |
Tejun Heo | 3dd06ff | 2014-03-19 10:23:54 -0400 | [diff] [blame] | 641 | struct cgroup_root *root; |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 642 | |
Tejun Heo | 0adb070 | 2014-02-12 09:29:48 -0500 | [diff] [blame] | 643 | /* |
| 644 | * List of cftypes. Each entry is the first entry of an array |
| 645 | * terminated by zero length name. |
| 646 | */ |
| 647 | struct list_head cfts; |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 648 | |
Tejun Heo | de00ffa | 2014-02-11 11:52:48 -0500 | [diff] [blame] | 649 | /* base cftypes, automatically registered with subsys itself */ |
Tejun Heo | 8e3f654 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 650 | struct cftype *base_cftypes; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 651 | }; |
| 652 | |
Tejun Heo | 073219e | 2014-02-08 10:36:58 -0500 | [diff] [blame] | 653 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 654 | #include <linux/cgroup_subsys.h> |
| 655 | #undef SUBSYS |
| 656 | |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 657 | /** |
Tejun Heo | 6387698 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 658 | * css_parent - find the parent css |
| 659 | * @css: the target cgroup_subsys_state |
| 660 | * |
| 661 | * Return the parent css of @css. This function is guaranteed to return |
| 662 | * non-NULL parent as long as @css isn't the root. |
| 663 | */ |
| 664 | static inline |
| 665 | struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) |
| 666 | { |
Tejun Heo | 0ae78e0 | 2013-08-13 11:01:54 -0400 | [diff] [blame] | 667 | return css->parent; |
Tejun Heo | 6387698 | 2013-08-08 20:11:23 -0400 | [diff] [blame] | 668 | } |
| 669 | |
| 670 | /** |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 671 | * task_css_set_check - obtain a task's css_set with extra access conditions |
| 672 | * @task: the task to obtain css_set for |
| 673 | * @__c: extra condition expression to be passed to rcu_dereference_check() |
| 674 | * |
| 675 | * A task's css_set is RCU protected, initialized and exited while holding |
| 676 | * task_lock(), and can only be modified while holding both cgroup_mutex |
| 677 | * and task_lock() while the task is alive. This macro verifies that the |
| 678 | * caller is inside proper critical section and returns @task's css_set. |
| 679 | * |
| 680 | * The caller can also specify additional allowed conditions via @__c, such |
| 681 | * as locks used during the cgroup_subsys::attach() methods. |
Peter Zijlstra | dc61b1d | 2010-06-08 11:40:42 +0200 | [diff] [blame] | 682 | */ |
Tejun Heo | 2219449 | 2013-04-07 09:29:51 -0700 | [diff] [blame] | 683 | #ifdef CONFIG_PROVE_RCU |
| 684 | extern struct mutex cgroup_mutex; |
Tejun Heo | 0e1d768 | 2014-02-25 10:04:03 -0500 | [diff] [blame] | 685 | extern struct rw_semaphore css_set_rwsem; |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 686 | #define task_css_set_check(task, __c) \ |
| 687 | rcu_dereference_check((task)->cgroups, \ |
Tejun Heo | 0e1d768 | 2014-02-25 10:04:03 -0500 | [diff] [blame] | 688 | lockdep_is_held(&cgroup_mutex) || \ |
| 689 | lockdep_is_held(&css_set_rwsem) || \ |
| 690 | ((task)->flags & PF_EXITING) || (__c)) |
Tejun Heo | 2219449 | 2013-04-07 09:29:51 -0700 | [diff] [blame] | 691 | #else |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 692 | #define task_css_set_check(task, __c) \ |
| 693 | rcu_dereference((task)->cgroups) |
Tejun Heo | 2219449 | 2013-04-07 09:29:51 -0700 | [diff] [blame] | 694 | #endif |
Peter Zijlstra | dc61b1d | 2010-06-08 11:40:42 +0200 | [diff] [blame] | 695 | |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 696 | /** |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 697 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 698 | * @task: the target task |
| 699 | * @subsys_id: the target subsystem ID |
| 700 | * @__c: extra condition expression to be passed to rcu_dereference_check() |
| 701 | * |
| 702 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The |
| 703 | * synchronization rules are the same as task_css_set_check(). |
| 704 | */ |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 705 | #define task_css_check(task, subsys_id, __c) \ |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 706 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
| 707 | |
| 708 | /** |
| 709 | * task_css_set - obtain a task's css_set |
| 710 | * @task: the task to obtain css_set for |
| 711 | * |
| 712 | * See task_css_set_check(). |
| 713 | */ |
| 714 | static inline struct css_set *task_css_set(struct task_struct *task) |
| 715 | { |
| 716 | return task_css_set_check(task, false); |
| 717 | } |
| 718 | |
| 719 | /** |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 720 | * task_css - obtain css for (task, subsys) |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 721 | * @task: the target task |
| 722 | * @subsys_id: the target subsystem ID |
| 723 | * |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 724 | * See task_css_check(). |
Tejun Heo | 14611e5 | 2013-06-25 11:48:32 -0700 | [diff] [blame] | 725 | */ |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 726 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
| 727 | int subsys_id) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 728 | { |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 729 | return task_css_check(task, subsys_id, false); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 730 | } |
| 731 | |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 732 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
| 733 | int subsys_id) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 734 | { |
Tejun Heo | 8af01f5 | 2013-08-08 20:11:22 -0400 | [diff] [blame] | 735 | return task_css(task, subsys_id)->cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 736 | } |
| 737 | |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 738 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, |
| 739 | struct cgroup_subsys_state *parent); |
Tejun Heo | 53fa526 | 2013-05-24 10:55:38 +0900 | [diff] [blame] | 740 | |
Li Zefan | 1cb650b | 2013-08-19 10:05:24 +0800 | [diff] [blame] | 741 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); |
| 742 | |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 743 | /** |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 744 | * css_for_each_child - iterate through children of a css |
| 745 | * @pos: the css * to use as the loop cursor |
| 746 | * @parent: css whose children to walk |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 747 | * |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 748 | * Walk @parent's children. Must be called under rcu_read_lock(). A child |
| 749 | * css which hasn't finished ->css_online() or already has finished |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 750 | * ->css_offline() may show up during traversal and it's each subsystem's |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 751 | * responsibility to verify that each @pos is alive. |
| 752 | * |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 753 | * If a subsystem synchronizes against the parent in its ->css_online() and |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 754 | * before starting iterating, a css which finished ->css_online() is |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 755 | * guaranteed to be visible in the future iterations. |
Tejun Heo | 75501a6 | 2013-05-24 10:55:38 +0900 | [diff] [blame] | 756 | * |
| 757 | * It is allowed to temporarily drop RCU read lock during iteration. The |
| 758 | * caller is responsible for ensuring that @pos remains accessible until |
| 759 | * the start of the next iteration by, for example, bumping the css refcnt. |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 760 | */ |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 761 | #define css_for_each_child(pos, parent) \ |
| 762 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ |
| 763 | (pos) = css_next_child((pos), (parent))) |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 764 | |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 765 | struct cgroup_subsys_state * |
| 766 | css_next_descendant_pre(struct cgroup_subsys_state *pos, |
| 767 | struct cgroup_subsys_state *css); |
| 768 | |
| 769 | struct cgroup_subsys_state * |
| 770 | css_rightmost_descendant(struct cgroup_subsys_state *pos); |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 771 | |
| 772 | /** |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 773 | * css_for_each_descendant_pre - pre-order walk of a css's descendants |
| 774 | * @pos: the css * to use as the loop cursor |
| 775 | * @root: css whose descendants to walk |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 776 | * |
Tejun Heo | bd8815a | 2013-08-08 20:11:27 -0400 | [diff] [blame] | 777 | * Walk @root's descendants. @root is included in the iteration and the |
| 778 | * first node to be visited. Must be called under rcu_read_lock(). A |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 779 | * descendant css which hasn't finished ->css_online() or already has |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 780 | * finished ->css_offline() may show up during traversal and it's each |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 781 | * subsystem's responsibility to verify that each @pos is alive. |
| 782 | * |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 783 | * If a subsystem synchronizes against the parent in its ->css_online() and |
| 784 | * before starting iterating, and synchronizes against @pos on each |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 785 | * iteration, any descendant css which finished ->css_online() is |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 786 | * guaranteed to be visible in the future iterations. |
| 787 | * |
| 788 | * In other words, the following guarantees that a descendant can't escape |
| 789 | * state updates of its ancestors. |
| 790 | * |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 791 | * my_online(@css) |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 792 | * { |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 793 | * Lock @css's parent and @css; |
| 794 | * Inherit state from the parent; |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 795 | * Unlock both. |
| 796 | * } |
| 797 | * |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 798 | * my_update_state(@css) |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 799 | * { |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 800 | * css_for_each_descendant_pre(@pos, @css) { |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 801 | * Lock @pos; |
Tejun Heo | bd8815a | 2013-08-08 20:11:27 -0400 | [diff] [blame] | 802 | * if (@pos == @css) |
| 803 | * Update @css's state; |
| 804 | * else |
| 805 | * Verify @pos is alive and inherit state from its parent; |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 806 | * Unlock @pos; |
| 807 | * } |
| 808 | * } |
| 809 | * |
| 810 | * As long as the inheriting step, including checking the parent state, is |
| 811 | * enclosed inside @pos locking, double-locking the parent isn't necessary |
| 812 | * while inheriting. The state update to the parent is guaranteed to be |
| 813 | * visible by walking order and, as long as inheriting operations to the |
| 814 | * same @pos are atomic to each other, multiple updates racing each other |
| 815 | * still result in the correct state. It's guaranateed that at least one |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 816 | * inheritance happens for any css after the latest update to its parent. |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 817 | * |
| 818 | * If checking parent's state requires locking the parent, each inheriting |
| 819 | * iteration should lock and unlock both @pos->parent and @pos. |
| 820 | * |
| 821 | * Alternatively, a subsystem may choose to use a single global lock to |
Tejun Heo | 92fb974 | 2012-11-19 08:13:38 -0800 | [diff] [blame] | 822 | * synchronize ->css_online() and ->css_offline() against tree-walking |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 823 | * operations. |
Tejun Heo | 75501a6 | 2013-05-24 10:55:38 +0900 | [diff] [blame] | 824 | * |
| 825 | * It is allowed to temporarily drop RCU read lock during iteration. The |
| 826 | * caller is responsible for ensuring that @pos remains accessible until |
| 827 | * the start of the next iteration by, for example, bumping the css refcnt. |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 828 | */ |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 829 | #define css_for_each_descendant_pre(pos, css) \ |
| 830 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ |
| 831 | (pos) = css_next_descendant_pre((pos), (css))) |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 832 | |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 833 | struct cgroup_subsys_state * |
| 834 | css_next_descendant_post(struct cgroup_subsys_state *pos, |
| 835 | struct cgroup_subsys_state *css); |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 836 | |
| 837 | /** |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 838 | * css_for_each_descendant_post - post-order walk of a css's descendants |
| 839 | * @pos: the css * to use as the loop cursor |
| 840 | * @css: css whose descendants to walk |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 841 | * |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 842 | * Similar to css_for_each_descendant_pre() but performs post-order |
Tejun Heo | bd8815a | 2013-08-08 20:11:27 -0400 | [diff] [blame] | 843 | * traversal instead. @root is included in the iteration and the last |
| 844 | * node to be visited. Note that the walk visibility guarantee described |
| 845 | * in pre-order walk doesn't apply the same to post-order walks. |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 846 | */ |
Tejun Heo | 492eb21 | 2013-08-08 20:11:25 -0400 | [diff] [blame] | 847 | #define css_for_each_descendant_post(pos, css) \ |
| 848 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ |
| 849 | (pos) = css_next_descendant_post((pos), (css))) |
Tejun Heo | 574bd9f | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 850 | |
Tejun Heo | 72ec702 | 2013-08-08 20:11:26 -0400 | [diff] [blame] | 851 | /* A css_task_iter should be treated as an opaque object */ |
| 852 | struct css_task_iter { |
Tejun Heo | 3ebb2b6 | 2014-04-23 11:13:15 -0400 | [diff] [blame] | 853 | struct cgroup_subsys *ss; |
| 854 | |
Tejun Heo | 0f0a2b4 | 2014-04-23 11:13:15 -0400 | [diff] [blame] | 855 | struct list_head *cset_pos; |
| 856 | struct list_head *cset_head; |
| 857 | |
| 858 | struct list_head *task_pos; |
| 859 | struct list_head *tasks_head; |
| 860 | struct list_head *mg_tasks_head; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 861 | }; |
| 862 | |
Tejun Heo | 72ec702 | 2013-08-08 20:11:26 -0400 | [diff] [blame] | 863 | void css_task_iter_start(struct cgroup_subsys_state *css, |
| 864 | struct css_task_iter *it); |
| 865 | struct task_struct *css_task_iter_next(struct css_task_iter *it); |
| 866 | void css_task_iter_end(struct css_task_iter *it); |
Tejun Heo | e535837 | 2013-08-08 20:11:26 -0400 | [diff] [blame] | 867 | |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 868 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
Tejun Heo | 8cc9934 | 2013-04-07 09:29:50 -0700 | [diff] [blame] | 869 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 870 | |
Tejun Heo | 5a17f54 | 2014-02-11 11:52:47 -0500 | [diff] [blame] | 871 | struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry, |
| 872 | struct cgroup_subsys *ss); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 873 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 874 | #else /* !CONFIG_CGROUPS */ |
| 875 | |
| 876 | static inline int cgroup_init_early(void) { return 0; } |
| 877 | static inline int cgroup_init(void) { return 0; } |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 878 | static inline void cgroup_fork(struct task_struct *p) {} |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 879 | static inline void cgroup_post_fork(struct task_struct *p) {} |
Li Zefan | 1ec4183 | 2014-03-28 15:22:19 +0800 | [diff] [blame] | 880 | static inline void cgroup_exit(struct task_struct *p) {} |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 881 | |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 882 | static inline int cgroupstats_build(struct cgroupstats *stats, |
| 883 | struct dentry *dentry) |
| 884 | { |
| 885 | return -EINVAL; |
| 886 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 887 | |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 888 | /* No cgroups - nothing to do */ |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 889 | static inline int cgroup_attach_task_all(struct task_struct *from, |
| 890 | struct task_struct *t) |
| 891 | { |
| 892 | return 0; |
| 893 | } |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 894 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 895 | #endif /* !CONFIG_CGROUPS */ |
| 896 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 897 | #endif /* _LINUX_CGROUP_H */ |