Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 1 | /* |
| 2 | * cgroup_freezer.c - control group freezer subsystem |
| 3 | * |
| 4 | * Copyright IBM Corporation, 2007 |
| 5 | * |
| 6 | * Author : Cedric Le Goater <clg@fr.ibm.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify it |
| 9 | * under the terms of version 2.1 of the GNU Lesser General Public License |
| 10 | * as published by the Free Software Foundation. |
| 11 | * |
| 12 | * This program is distributed in the hope that it would be useful, but |
| 13 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| 15 | */ |
| 16 | |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 17 | #include <linux/export.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 18 | #include <linux/slab.h> |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 19 | #include <linux/cgroup.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/uaccess.h> |
| 22 | #include <linux/freezer.h> |
| 23 | #include <linux/seq_file.h> |
| 24 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 25 | enum freezer_state_flags { |
| 26 | CGROUP_FREEZING = (1 << 1), /* this freezer is freezing */ |
| 27 | CGROUP_FROZEN = (1 << 3), /* this and its descendants frozen */ |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 28 | }; |
| 29 | |
| 30 | struct freezer { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 31 | struct cgroup_subsys_state css; |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 32 | unsigned int state; |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 33 | spinlock_t lock; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 34 | }; |
| 35 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 36 | static inline struct freezer *cgroup_freezer(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 37 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 38 | return container_of(cgroup_subsys_state(cgroup, freezer_subsys_id), |
| 39 | struct freezer, css); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 40 | } |
| 41 | |
| 42 | static inline struct freezer *task_freezer(struct task_struct *task) |
| 43 | { |
| 44 | return container_of(task_subsys_state(task, freezer_subsys_id), |
| 45 | struct freezer, css); |
| 46 | } |
| 47 | |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 48 | bool cgroup_freezing(struct task_struct *task) |
Tomasz Buchert | d5de4ddb | 2010-10-27 15:33:32 -0700 | [diff] [blame] | 49 | { |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 50 | bool ret; |
Tomasz Buchert | d5de4ddb | 2010-10-27 15:33:32 -0700 | [diff] [blame] | 51 | |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 52 | rcu_read_lock(); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 53 | ret = task_freezer(task)->state & CGROUP_FREEZING; |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 54 | rcu_read_unlock(); |
| 55 | |
| 56 | return ret; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 57 | } |
| 58 | |
| 59 | /* |
| 60 | * cgroups_write_string() limits the size of freezer state strings to |
| 61 | * CGROUP_LOCAL_BUFFER_SIZE |
| 62 | */ |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 63 | static const char *freezer_state_strs(unsigned int state) |
| 64 | { |
| 65 | if (state & CGROUP_FROZEN) |
| 66 | return "FROZEN"; |
| 67 | if (state & CGROUP_FREEZING) |
| 68 | return "FREEZING"; |
| 69 | return "THAWED"; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 70 | }; |
| 71 | |
| 72 | /* |
| 73 | * State diagram |
| 74 | * Transitions are caused by userspace writes to the freezer.state file. |
| 75 | * The values in parenthesis are state labels. The rest are edge labels. |
| 76 | * |
Matt Helsley | 81dcf33 | 2008-10-18 20:27:23 -0700 | [diff] [blame] | 77 | * (THAWED) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN) |
| 78 | * ^ ^ | | |
| 79 | * | \_______THAWED_______/ | |
| 80 | * \__________________________THAWED____________/ |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 81 | */ |
| 82 | |
| 83 | struct cgroup_subsys freezer_subsys; |
| 84 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 85 | static struct cgroup_subsys_state *freezer_create(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 86 | { |
| 87 | struct freezer *freezer; |
| 88 | |
| 89 | freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL); |
| 90 | if (!freezer) |
| 91 | return ERR_PTR(-ENOMEM); |
| 92 | |
| 93 | spin_lock_init(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 94 | return &freezer->css; |
| 95 | } |
| 96 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 97 | static void freezer_destroy(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 98 | { |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 99 | struct freezer *freezer = cgroup_freezer(cgroup); |
| 100 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 101 | if (freezer->state & CGROUP_FREEZING) |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 102 | atomic_dec(&system_freezing_cnt); |
| 103 | kfree(freezer); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 104 | } |
| 105 | |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 106 | /* |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 107 | * Tasks can be migrated into a different freezer anytime regardless of its |
| 108 | * current state. freezer_attach() is responsible for making new tasks |
| 109 | * conform to the current state. |
| 110 | * |
| 111 | * Freezer state changes and task migration are synchronized via |
| 112 | * @freezer->lock. freezer_attach() makes the new tasks conform to the |
| 113 | * current state and all following state changes can see the new tasks. |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 114 | */ |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 115 | static void freezer_attach(struct cgroup *new_cgrp, struct cgroup_taskset *tset) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 116 | { |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 117 | struct freezer *freezer = cgroup_freezer(new_cgrp); |
Tejun Heo | bb9d97b | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 118 | struct task_struct *task; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 119 | |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 120 | spin_lock_irq(&freezer->lock); |
| 121 | |
Li Zefan | 80a6a2c | 2008-10-29 14:00:52 -0700 | [diff] [blame] | 122 | /* |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 123 | * Make the new tasks conform to the current state of @new_cgrp. |
| 124 | * For simplicity, when migrating any task to a FROZEN cgroup, we |
| 125 | * revert it to FREEZING and let update_if_frozen() determine the |
| 126 | * correct state later. |
| 127 | * |
| 128 | * Tasks in @tset are on @new_cgrp but may not conform to its |
| 129 | * current state before executing the following - !frozen tasks may |
| 130 | * be visible in a FROZEN cgroup and frozen tasks in a THAWED one. |
Li Zefan | 80a6a2c | 2008-10-29 14:00:52 -0700 | [diff] [blame] | 131 | */ |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 132 | cgroup_taskset_for_each(task, new_cgrp, tset) { |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 133 | if (!(freezer->state & CGROUP_FREEZING)) { |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 134 | __thaw_task(task); |
| 135 | } else { |
| 136 | freeze_task(task); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 137 | freezer->state &= ~CGROUP_FROZEN; |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 138 | } |
| 139 | } |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 140 | |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 141 | spin_unlock_irq(&freezer->lock); |
Ben Blum | f780bdb | 2011-05-26 16:25:19 -0700 | [diff] [blame] | 142 | } |
| 143 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 144 | static void freezer_fork(struct task_struct *task) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 145 | { |
| 146 | struct freezer *freezer; |
| 147 | |
Paul E. McKenney | 8b46f88 | 2010-04-21 13:02:08 -0700 | [diff] [blame] | 148 | rcu_read_lock(); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 149 | freezer = task_freezer(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 150 | |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 151 | /* |
| 152 | * The root cgroup is non-freezable, so we can skip the |
| 153 | * following check. |
| 154 | */ |
| 155 | if (!freezer->css.cgroup->parent) |
Tejun Heo | 5edee61 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 156 | goto out; |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 157 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 158 | spin_lock_irq(&freezer->lock); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 159 | if (freezer->state & CGROUP_FREEZING) |
Tejun Heo | 839e340 | 2011-11-21 12:32:26 -0800 | [diff] [blame] | 160 | freeze_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 161 | spin_unlock_irq(&freezer->lock); |
Tejun Heo | 5edee61 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 162 | out: |
| 163 | rcu_read_unlock(); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 164 | } |
| 165 | |
| 166 | /* |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 167 | * We change from FREEZING to FROZEN lazily if the cgroup was only |
| 168 | * partially frozen when we exitted write. Caller must hold freezer->lock. |
| 169 | * |
| 170 | * Task states and freezer state might disagree while tasks are being |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 171 | * migrated into or out of @cgroup, so we can't verify task states against |
| 172 | * @freezer state here. See freezer_attach() for details. |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 173 | */ |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 174 | static void update_if_frozen(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 175 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 176 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 177 | struct cgroup_iter it; |
| 178 | struct task_struct *task; |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 179 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 180 | if (!(freezer->state & CGROUP_FREEZING) || |
| 181 | (freezer->state & CGROUP_FROZEN)) |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 182 | return; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 183 | |
| 184 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 185 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 186 | while ((task = cgroup_iter_next(cgroup, &it))) { |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 187 | if (freezing(task)) { |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 188 | /* |
| 189 | * freezer_should_skip() indicates that the task |
| 190 | * should be skipped when determining freezing |
| 191 | * completion. Consider it frozen in addition to |
| 192 | * the usual frozen condition. |
| 193 | */ |
Oleg Nesterov | 5d8f72b | 2012-10-26 19:46:06 +0200 | [diff] [blame] | 194 | if (!frozen(task) && !freezer_should_skip(task)) |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 195 | goto notyet; |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 196 | } |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 197 | } |
| 198 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 199 | freezer->state |= CGROUP_FROZEN; |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 200 | notyet: |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 201 | cgroup_iter_end(cgroup, &it); |
| 202 | } |
| 203 | |
| 204 | static int freezer_read(struct cgroup *cgroup, struct cftype *cft, |
| 205 | struct seq_file *m) |
| 206 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 207 | struct freezer *freezer = cgroup_freezer(cgroup); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 208 | unsigned int state; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 209 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 210 | spin_lock_irq(&freezer->lock); |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 211 | update_if_frozen(freezer); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 212 | state = freezer->state; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 213 | spin_unlock_irq(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 214 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 215 | seq_puts(m, freezer_state_strs(state)); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 216 | seq_putc(m, '\n'); |
| 217 | return 0; |
| 218 | } |
| 219 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 220 | static void freeze_cgroup(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 221 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 222 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 223 | struct cgroup_iter it; |
| 224 | struct task_struct *task; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 225 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 226 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | 51f246e | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 227 | while ((task = cgroup_iter_next(cgroup, &it))) |
| 228 | freeze_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 229 | cgroup_iter_end(cgroup, &it); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 230 | } |
| 231 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 232 | static void unfreeze_cgroup(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 233 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 234 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 235 | struct cgroup_iter it; |
| 236 | struct task_struct *task; |
| 237 | |
| 238 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | a5be2d0 | 2011-11-21 12:32:23 -0800 | [diff] [blame] | 239 | while ((task = cgroup_iter_next(cgroup, &it))) |
| 240 | __thaw_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 241 | cgroup_iter_end(cgroup, &it); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 242 | } |
| 243 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 244 | /** |
| 245 | * freezer_apply_state - apply state change to a single cgroup_freezer |
| 246 | * @freezer: freezer to apply state change to |
| 247 | * @freeze: whether to freeze or unfreeze |
| 248 | */ |
| 249 | static void freezer_apply_state(struct freezer *freezer, bool freeze) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 250 | { |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 251 | /* also synchronizes against task migration, see freezer_attach() */ |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 252 | lockdep_assert_held(&freezer->lock); |
Li Zefan | 51308ee | 2008-10-29 14:00:54 -0700 | [diff] [blame] | 253 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 254 | if (freeze) { |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 255 | if (!(freezer->state & CGROUP_FREEZING)) |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 256 | atomic_inc(&system_freezing_cnt); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 257 | freezer->state |= CGROUP_FREEZING; |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 258 | freeze_cgroup(freezer); |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 259 | } else { |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 260 | if (freezer->state & CGROUP_FREEZING) |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 261 | atomic_dec(&system_freezing_cnt); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 262 | freezer->state &= ~(CGROUP_FREEZING | CGROUP_FROZEN); |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 263 | unfreeze_cgroup(freezer); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 264 | } |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 265 | } |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 266 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 267 | /** |
| 268 | * freezer_change_state - change the freezing state of a cgroup_freezer |
| 269 | * @freezer: freezer of interest |
| 270 | * @freeze: whether to freeze or thaw |
| 271 | * |
| 272 | * Freeze or thaw @cgroup according to @freeze. |
| 273 | */ |
| 274 | static void freezer_change_state(struct freezer *freezer, bool freeze) |
| 275 | { |
| 276 | /* update @freezer */ |
| 277 | spin_lock_irq(&freezer->lock); |
| 278 | freezer_apply_state(freezer, freeze); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 279 | spin_unlock_irq(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 280 | } |
| 281 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 282 | static int freezer_write(struct cgroup *cgroup, struct cftype *cft, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 283 | const char *buffer) |
| 284 | { |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 285 | bool freeze; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 286 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 287 | if (strcmp(buffer, freezer_state_strs(0)) == 0) |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 288 | freeze = false; |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 289 | else if (strcmp(buffer, freezer_state_strs(CGROUP_FROZEN)) == 0) |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 290 | freeze = true; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 291 | else |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 292 | return -EINVAL; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 293 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 294 | freezer_change_state(cgroup_freezer(cgroup), freeze); |
Tejun Heo | 51f246e | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 295 | return 0; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 296 | } |
| 297 | |
| 298 | static struct cftype files[] = { |
| 299 | { |
| 300 | .name = "state", |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 301 | .flags = CFTYPE_NOT_ON_ROOT, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 302 | .read_seq_string = freezer_read, |
| 303 | .write_string = freezer_write, |
| 304 | }, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 305 | { } /* terminate */ |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 306 | }; |
| 307 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 308 | struct cgroup_subsys freezer_subsys = { |
| 309 | .name = "freezer", |
| 310 | .create = freezer_create, |
| 311 | .destroy = freezer_destroy, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 312 | .subsys_id = freezer_subsys_id, |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 313 | .attach = freezer_attach, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 314 | .fork = freezer_fork, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 315 | .base_cftypes = files, |
Tejun Heo | 8c7f6ed | 2012-09-13 12:20:58 -0700 | [diff] [blame] | 316 | |
| 317 | /* |
| 318 | * freezer subsys doesn't handle hierarchy at all. Frozen state |
| 319 | * should be inherited through the hierarchy - if a parent is |
| 320 | * frozen, all its children should be frozen. Fix it and remove |
| 321 | * the following. |
| 322 | */ |
| 323 | .broken_hierarchy = true, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 324 | }; |