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 { |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 26 | CGROUP_FREEZER_ONLINE = (1 << 0), /* freezer is fully online */ |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 27 | CGROUP_FREEZING_SELF = (1 << 1), /* this freezer is freezing */ |
| 28 | CGROUP_FREEZING_PARENT = (1 << 2), /* the parent freezer is freezing */ |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 29 | CGROUP_FROZEN = (1 << 3), /* this and its descendants frozen */ |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 30 | |
| 31 | /* mask for all FREEZING flags */ |
| 32 | CGROUP_FREEZING = CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 33 | }; |
| 34 | |
| 35 | struct freezer { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 36 | struct cgroup_subsys_state css; |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 37 | unsigned int state; |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 38 | spinlock_t lock; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 39 | }; |
| 40 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 41 | static inline struct freezer *cgroup_freezer(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 42 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 43 | return container_of(cgroup_subsys_state(cgroup, freezer_subsys_id), |
| 44 | struct freezer, css); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 45 | } |
| 46 | |
| 47 | static inline struct freezer *task_freezer(struct task_struct *task) |
| 48 | { |
| 49 | return container_of(task_subsys_state(task, freezer_subsys_id), |
| 50 | struct freezer, css); |
| 51 | } |
| 52 | |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 53 | bool cgroup_freezing(struct task_struct *task) |
Tomasz Buchert | d5de4ddb | 2010-10-27 15:33:32 -0700 | [diff] [blame] | 54 | { |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 55 | bool ret; |
Tomasz Buchert | d5de4ddb | 2010-10-27 15:33:32 -0700 | [diff] [blame] | 56 | |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 57 | rcu_read_lock(); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 58 | ret = task_freezer(task)->state & CGROUP_FREEZING; |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 59 | rcu_read_unlock(); |
| 60 | |
| 61 | return ret; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 62 | } |
| 63 | |
| 64 | /* |
| 65 | * cgroups_write_string() limits the size of freezer state strings to |
| 66 | * CGROUP_LOCAL_BUFFER_SIZE |
| 67 | */ |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 68 | static const char *freezer_state_strs(unsigned int state) |
| 69 | { |
| 70 | if (state & CGROUP_FROZEN) |
| 71 | return "FROZEN"; |
| 72 | if (state & CGROUP_FREEZING) |
| 73 | return "FREEZING"; |
| 74 | return "THAWED"; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 75 | }; |
| 76 | |
| 77 | /* |
| 78 | * State diagram |
| 79 | * Transitions are caused by userspace writes to the freezer.state file. |
| 80 | * The values in parenthesis are state labels. The rest are edge labels. |
| 81 | * |
Matt Helsley | 81dcf33 | 2008-10-18 20:27:23 -0700 | [diff] [blame] | 82 | * (THAWED) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN) |
| 83 | * ^ ^ | | |
| 84 | * | \_______THAWED_______/ | |
| 85 | * \__________________________THAWED____________/ |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 86 | */ |
| 87 | |
| 88 | struct cgroup_subsys freezer_subsys; |
| 89 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 90 | static struct cgroup_subsys_state *freezer_create(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 91 | { |
| 92 | struct freezer *freezer; |
| 93 | |
| 94 | freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL); |
| 95 | if (!freezer) |
| 96 | return ERR_PTR(-ENOMEM); |
| 97 | |
| 98 | spin_lock_init(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 99 | return &freezer->css; |
| 100 | } |
| 101 | |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 102 | /** |
| 103 | * freezer_post_create - commit creation of a freezer cgroup |
| 104 | * @cgroup: cgroup being created |
| 105 | * |
| 106 | * We're committing to creation of @cgroup. Mark it online. |
| 107 | */ |
| 108 | static void freezer_post_create(struct cgroup *cgroup) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 109 | { |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 110 | struct freezer *freezer = cgroup_freezer(cgroup); |
| 111 | |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 112 | spin_lock_irq(&freezer->lock); |
| 113 | freezer->state |= CGROUP_FREEZER_ONLINE; |
| 114 | spin_unlock_irq(&freezer->lock); |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * freezer_pre_destroy - initiate destruction of @cgroup |
| 119 | * @cgroup: cgroup being destroyed |
| 120 | * |
| 121 | * @cgroup is going away. Mark it dead and decrement system_freezing_count |
| 122 | * if it was holding one. |
| 123 | */ |
| 124 | static void freezer_pre_destroy(struct cgroup *cgroup) |
| 125 | { |
| 126 | struct freezer *freezer = cgroup_freezer(cgroup); |
| 127 | |
| 128 | spin_lock_irq(&freezer->lock); |
| 129 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 130 | if (freezer->state & CGROUP_FREEZING) |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 131 | atomic_dec(&system_freezing_cnt); |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 132 | |
| 133 | freezer->state = 0; |
| 134 | |
| 135 | spin_unlock_irq(&freezer->lock); |
| 136 | } |
| 137 | |
| 138 | static void freezer_destroy(struct cgroup *cgroup) |
| 139 | { |
| 140 | kfree(cgroup_freezer(cgroup)); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 141 | } |
| 142 | |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 143 | /* |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 144 | * Tasks can be migrated into a different freezer anytime regardless of its |
| 145 | * current state. freezer_attach() is responsible for making new tasks |
| 146 | * conform to the current state. |
| 147 | * |
| 148 | * Freezer state changes and task migration are synchronized via |
| 149 | * @freezer->lock. freezer_attach() makes the new tasks conform to the |
| 150 | * current state and all following state changes can see the new tasks. |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 151 | */ |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 152 | static void freezer_attach(struct cgroup *new_cgrp, struct cgroup_taskset *tset) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 153 | { |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 154 | struct freezer *freezer = cgroup_freezer(new_cgrp); |
Tejun Heo | bb9d97b | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 155 | struct task_struct *task; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 156 | |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 157 | spin_lock_irq(&freezer->lock); |
| 158 | |
Li Zefan | 80a6a2c | 2008-10-29 14:00:52 -0700 | [diff] [blame] | 159 | /* |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 160 | * Make the new tasks conform to the current state of @new_cgrp. |
| 161 | * For simplicity, when migrating any task to a FROZEN cgroup, we |
| 162 | * revert it to FREEZING and let update_if_frozen() determine the |
| 163 | * correct state later. |
| 164 | * |
| 165 | * Tasks in @tset are on @new_cgrp but may not conform to its |
| 166 | * current state before executing the following - !frozen tasks may |
| 167 | * 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] | 168 | */ |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 169 | cgroup_taskset_for_each(task, new_cgrp, tset) { |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 170 | if (!(freezer->state & CGROUP_FREEZING)) { |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 171 | __thaw_task(task); |
| 172 | } else { |
| 173 | freeze_task(task); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 174 | freezer->state &= ~CGROUP_FROZEN; |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 175 | } |
| 176 | } |
Matt Helsley | 957a4ee | 2008-10-18 20:27:22 -0700 | [diff] [blame] | 177 | |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 178 | spin_unlock_irq(&freezer->lock); |
Ben Blum | f780bdb | 2011-05-26 16:25:19 -0700 | [diff] [blame] | 179 | } |
| 180 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 181 | static void freezer_fork(struct task_struct *task) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 182 | { |
| 183 | struct freezer *freezer; |
| 184 | |
Paul E. McKenney | 8b46f88 | 2010-04-21 13:02:08 -0700 | [diff] [blame] | 185 | rcu_read_lock(); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 186 | freezer = task_freezer(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 187 | |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 188 | /* |
| 189 | * The root cgroup is non-freezable, so we can skip the |
| 190 | * following check. |
| 191 | */ |
| 192 | if (!freezer->css.cgroup->parent) |
Tejun Heo | 5edee61 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 193 | goto out; |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 194 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 195 | spin_lock_irq(&freezer->lock); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 196 | if (freezer->state & CGROUP_FREEZING) |
Tejun Heo | 839e340 | 2011-11-21 12:32:26 -0800 | [diff] [blame] | 197 | freeze_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 198 | spin_unlock_irq(&freezer->lock); |
Tejun Heo | 5edee61 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 199 | out: |
| 200 | rcu_read_unlock(); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 201 | } |
| 202 | |
| 203 | /* |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 204 | * We change from FREEZING to FROZEN lazily if the cgroup was only |
| 205 | * partially frozen when we exitted write. Caller must hold freezer->lock. |
| 206 | * |
| 207 | * Task states and freezer state might disagree while tasks are being |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 208 | * migrated into or out of @cgroup, so we can't verify task states against |
| 209 | * @freezer state here. See freezer_attach() for details. |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 210 | */ |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 211 | static void update_if_frozen(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 212 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 213 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 214 | struct cgroup_iter it; |
| 215 | struct task_struct *task; |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 216 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 217 | if (!(freezer->state & CGROUP_FREEZING) || |
| 218 | (freezer->state & CGROUP_FROZEN)) |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 219 | return; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 220 | |
| 221 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 222 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 223 | while ((task = cgroup_iter_next(cgroup, &it))) { |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 224 | if (freezing(task)) { |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 225 | /* |
| 226 | * freezer_should_skip() indicates that the task |
| 227 | * should be skipped when determining freezing |
| 228 | * completion. Consider it frozen in addition to |
| 229 | * the usual frozen condition. |
| 230 | */ |
Oleg Nesterov | 5d8f72b | 2012-10-26 19:46:06 +0200 | [diff] [blame] | 231 | if (!frozen(task) && !freezer_should_skip(task)) |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 232 | goto notyet; |
Tejun Heo | 3c426d5 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 233 | } |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 234 | } |
| 235 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 236 | freezer->state |= CGROUP_FROZEN; |
Tejun Heo | b4d1831 | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 237 | notyet: |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 238 | cgroup_iter_end(cgroup, &it); |
| 239 | } |
| 240 | |
| 241 | static int freezer_read(struct cgroup *cgroup, struct cftype *cft, |
| 242 | struct seq_file *m) |
| 243 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 244 | struct freezer *freezer = cgroup_freezer(cgroup); |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 245 | unsigned int state; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 246 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 247 | spin_lock_irq(&freezer->lock); |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 248 | update_if_frozen(freezer); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 249 | state = freezer->state; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 250 | spin_unlock_irq(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 251 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 252 | seq_puts(m, freezer_state_strs(state)); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 253 | seq_putc(m, '\n'); |
| 254 | return 0; |
| 255 | } |
| 256 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 257 | static void freeze_cgroup(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 258 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 259 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 260 | struct cgroup_iter it; |
| 261 | struct task_struct *task; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 262 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 263 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | 51f246e | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 264 | while ((task = cgroup_iter_next(cgroup, &it))) |
| 265 | freeze_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 266 | cgroup_iter_end(cgroup, &it); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 267 | } |
| 268 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 269 | static void unfreeze_cgroup(struct freezer *freezer) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 270 | { |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 271 | struct cgroup *cgroup = freezer->css.cgroup; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 272 | struct cgroup_iter it; |
| 273 | struct task_struct *task; |
| 274 | |
| 275 | cgroup_iter_start(cgroup, &it); |
Tejun Heo | a5be2d0 | 2011-11-21 12:32:23 -0800 | [diff] [blame] | 276 | while ((task = cgroup_iter_next(cgroup, &it))) |
| 277 | __thaw_task(task); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 278 | cgroup_iter_end(cgroup, &it); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 279 | } |
| 280 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 281 | /** |
| 282 | * freezer_apply_state - apply state change to a single cgroup_freezer |
| 283 | * @freezer: freezer to apply state change to |
| 284 | * @freeze: whether to freeze or unfreeze |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 285 | * @state: CGROUP_FREEZING_* flag to set or clear |
| 286 | * |
| 287 | * Set or clear @state on @cgroup according to @freeze, and perform |
| 288 | * freezing or thawing as necessary. |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 289 | */ |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 290 | static void freezer_apply_state(struct freezer *freezer, bool freeze, |
| 291 | unsigned int state) |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 292 | { |
Tejun Heo | ead5c47 | 2012-10-16 15:03:15 -0700 | [diff] [blame] | 293 | /* also synchronizes against task migration, see freezer_attach() */ |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 294 | lockdep_assert_held(&freezer->lock); |
Li Zefan | 51308ee | 2008-10-29 14:00:54 -0700 | [diff] [blame] | 295 | |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 296 | if (!(freezer->state & CGROUP_FREEZER_ONLINE)) |
| 297 | return; |
| 298 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 299 | if (freeze) { |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 300 | if (!(freezer->state & CGROUP_FREEZING)) |
Tejun Heo | a320122 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 301 | atomic_inc(&system_freezing_cnt); |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 302 | freezer->state |= state; |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 303 | freeze_cgroup(freezer); |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 304 | } else { |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 305 | bool was_freezing = freezer->state & CGROUP_FREEZING; |
| 306 | |
| 307 | freezer->state &= ~state; |
| 308 | |
| 309 | if (!(freezer->state & CGROUP_FREEZING)) { |
| 310 | if (was_freezing) |
| 311 | atomic_dec(&system_freezing_cnt); |
| 312 | freezer->state &= ~CGROUP_FROZEN; |
| 313 | unfreeze_cgroup(freezer); |
| 314 | } |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 315 | } |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 316 | } |
Tejun Heo | 22b4e11 | 2011-11-21 12:32:25 -0800 | [diff] [blame] | 317 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 318 | /** |
| 319 | * freezer_change_state - change the freezing state of a cgroup_freezer |
| 320 | * @freezer: freezer of interest |
| 321 | * @freeze: whether to freeze or thaw |
| 322 | * |
| 323 | * Freeze or thaw @cgroup according to @freeze. |
| 324 | */ |
| 325 | static void freezer_change_state(struct freezer *freezer, bool freeze) |
| 326 | { |
| 327 | /* update @freezer */ |
| 328 | spin_lock_irq(&freezer->lock); |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 329 | freezer_apply_state(freezer, freeze, CGROUP_FREEZING_SELF); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 330 | spin_unlock_irq(&freezer->lock); |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 331 | } |
| 332 | |
Tejun Heo | bcd66c8 | 2012-11-09 09:12:29 -0800 | [diff] [blame] | 333 | static int freezer_write(struct cgroup *cgroup, struct cftype *cft, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 334 | const char *buffer) |
| 335 | { |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 336 | bool freeze; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 337 | |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 338 | if (strcmp(buffer, freezer_state_strs(0)) == 0) |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 339 | freeze = false; |
Tejun Heo | d6a2fe1 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 340 | else if (strcmp(buffer, freezer_state_strs(CGROUP_FROZEN)) == 0) |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 341 | freeze = true; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 342 | else |
Li Zefan | 3b1b3f6 | 2008-11-12 13:26:50 -0800 | [diff] [blame] | 343 | return -EINVAL; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 344 | |
Tejun Heo | 04a4ec3 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 345 | freezer_change_state(cgroup_freezer(cgroup), freeze); |
Tejun Heo | 51f246e | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 346 | return 0; |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 347 | } |
| 348 | |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 349 | static u64 freezer_self_freezing_read(struct cgroup *cgroup, struct cftype *cft) |
| 350 | { |
| 351 | struct freezer *freezer = cgroup_freezer(cgroup); |
| 352 | |
| 353 | return (bool)(freezer->state & CGROUP_FREEZING_SELF); |
| 354 | } |
| 355 | |
| 356 | static u64 freezer_parent_freezing_read(struct cgroup *cgroup, struct cftype *cft) |
| 357 | { |
| 358 | struct freezer *freezer = cgroup_freezer(cgroup); |
| 359 | |
| 360 | return (bool)(freezer->state & CGROUP_FREEZING_PARENT); |
| 361 | } |
| 362 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 363 | static struct cftype files[] = { |
| 364 | { |
| 365 | .name = "state", |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 366 | .flags = CFTYPE_NOT_ON_ROOT, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 367 | .read_seq_string = freezer_read, |
| 368 | .write_string = freezer_write, |
| 369 | }, |
Tejun Heo | a225218 | 2012-11-09 09:12:30 -0800 | [diff] [blame] | 370 | { |
| 371 | .name = "self_freezing", |
| 372 | .flags = CFTYPE_NOT_ON_ROOT, |
| 373 | .read_u64 = freezer_self_freezing_read, |
| 374 | }, |
| 375 | { |
| 376 | .name = "parent_freezing", |
| 377 | .flags = CFTYPE_NOT_ON_ROOT, |
| 378 | .read_u64 = freezer_parent_freezing_read, |
| 379 | }, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 380 | { } /* terminate */ |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 381 | }; |
| 382 | |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 383 | struct cgroup_subsys freezer_subsys = { |
| 384 | .name = "freezer", |
| 385 | .create = freezer_create, |
Tejun Heo | 5300a9b | 2012-11-09 09:12:30 -0800 | [diff] [blame^] | 386 | .post_create = freezer_post_create, |
| 387 | .pre_destroy = freezer_pre_destroy, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 388 | .destroy = freezer_destroy, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 389 | .subsys_id = freezer_subsys_id, |
Tejun Heo | 8755ade | 2012-10-16 15:03:14 -0700 | [diff] [blame] | 390 | .attach = freezer_attach, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 391 | .fork = freezer_fork, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 392 | .base_cftypes = files, |
Tejun Heo | 8c7f6ed | 2012-09-13 12:20:58 -0700 | [diff] [blame] | 393 | |
| 394 | /* |
| 395 | * freezer subsys doesn't handle hierarchy at all. Frozen state |
| 396 | * should be inherited through the hierarchy - if a parent is |
| 397 | * frozen, all its children should be frozen. Fix it and remove |
| 398 | * the following. |
| 399 | */ |
| 400 | .broken_hierarchy = true, |
Matt Helsley | dc52ddc | 2008-10-18 20:27:21 -0700 | [diff] [blame] | 401 | }; |