Commit | Line | Data |
---|---|---|
dc52ddc0 MH |
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 | ||
9984de1a | 17 | #include <linux/export.h> |
5a0e3ad6 | 18 | #include <linux/slab.h> |
dc52ddc0 MH |
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> | |
e5ced8eb | 24 | #include <linux/mutex.h> |
57dcd64c | 25 | #include <linux/cpu.h> |
dc52ddc0 | 26 | |
ef9fe980 TH |
27 | /* |
28 | * A cgroup is freezing if any FREEZING flags are set. FREEZING_SELF is | |
29 | * set if "FROZEN" is written to freezer.state cgroupfs file, and cleared | |
30 | * for "THAWED". FREEZING_PARENT is set if the parent freezer is FREEZING | |
31 | * for whatever reason. IOW, a cgroup has FREEZING_PARENT set if one of | |
32 | * its ancestors has FREEZING_SELF set. | |
33 | */ | |
d6a2fe13 | 34 | enum freezer_state_flags { |
5300a9b3 | 35 | CGROUP_FREEZER_ONLINE = (1 << 0), /* freezer is fully online */ |
a2252180 TH |
36 | CGROUP_FREEZING_SELF = (1 << 1), /* this freezer is freezing */ |
37 | CGROUP_FREEZING_PARENT = (1 << 2), /* the parent freezer is freezing */ | |
d6a2fe13 | 38 | CGROUP_FROZEN = (1 << 3), /* this and its descendants frozen */ |
a2252180 TH |
39 | |
40 | /* mask for all FREEZING flags */ | |
41 | CGROUP_FREEZING = CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT, | |
dc52ddc0 MH |
42 | }; |
43 | ||
44 | struct freezer { | |
bcd66c89 | 45 | struct cgroup_subsys_state css; |
d6a2fe13 | 46 | unsigned int state; |
dc52ddc0 MH |
47 | }; |
48 | ||
e5ced8eb TH |
49 | static DEFINE_MUTEX(freezer_mutex); |
50 | ||
a7c6d554 TH |
51 | static inline struct freezer *css_freezer(struct cgroup_subsys_state *css) |
52 | { | |
53 | return css ? container_of(css, struct freezer, css) : NULL; | |
54 | } | |
55 | ||
dc52ddc0 MH |
56 | static inline struct freezer *task_freezer(struct task_struct *task) |
57 | { | |
073219e9 | 58 | return css_freezer(task_css(task, freezer_cgrp_id)); |
dc52ddc0 MH |
59 | } |
60 | ||
ef9fe980 TH |
61 | static struct freezer *parent_freezer(struct freezer *freezer) |
62 | { | |
5c9d535b | 63 | return css_freezer(freezer->css.parent); |
ef9fe980 TH |
64 | } |
65 | ||
22b4e111 | 66 | bool cgroup_freezing(struct task_struct *task) |
dc52ddc0 | 67 | { |
22b4e111 | 68 | bool ret; |
cff5f49d | 69 | unsigned int state; |
dc52ddc0 | 70 | |
22b4e111 | 71 | rcu_read_lock(); |
cff5f49d TVP |
72 | /* Check if the cgroup is still FREEZING, but not FROZEN. The extra |
73 | * !FROZEN check is required, because the FREEZING bit is not cleared | |
74 | * when the state FROZEN is reached. | |
75 | */ | |
76 | state = task_freezer(task)->state; | |
77 | ret = (state & CGROUP_FREEZING) && !(state & CGROUP_FROZEN); | |
22b4e111 TH |
78 | rcu_read_unlock(); |
79 | ||
80 | return ret; | |
dc52ddc0 MH |
81 | } |
82 | ||
d6a2fe13 TH |
83 | static const char *freezer_state_strs(unsigned int state) |
84 | { | |
85 | if (state & CGROUP_FROZEN) | |
86 | return "FROZEN"; | |
87 | if (state & CGROUP_FREEZING) | |
88 | return "FREEZING"; | |
89 | return "THAWED"; | |
dc52ddc0 MH |
90 | }; |
91 | ||
eb95419b TH |
92 | static struct cgroup_subsys_state * |
93 | freezer_css_alloc(struct cgroup_subsys_state *parent_css) | |
dc52ddc0 MH |
94 | { |
95 | struct freezer *freezer; | |
96 | ||
97 | freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL); | |
98 | if (!freezer) | |
99 | return ERR_PTR(-ENOMEM); | |
100 | ||
dc52ddc0 MH |
101 | return &freezer->css; |
102 | } | |
103 | ||
5300a9b3 | 104 | /** |
eb95419b TH |
105 | * freezer_css_online - commit creation of a freezer css |
106 | * @css: css being created | |
5300a9b3 | 107 | * |
eb95419b | 108 | * We're committing to creation of @css. Mark it online and inherit |
a6b8daba | 109 | * parent's freezing state while holding cpus read lock and freezer_mutex. |
5300a9b3 | 110 | */ |
eb95419b | 111 | static int freezer_css_online(struct cgroup_subsys_state *css) |
dc52ddc0 | 112 | { |
eb95419b | 113 | struct freezer *freezer = css_freezer(css); |
ef9fe980 TH |
114 | struct freezer *parent = parent_freezer(freezer); |
115 | ||
f0cc7492 | 116 | cpus_read_lock(); |
e5ced8eb | 117 | mutex_lock(&freezer_mutex); |
a3201227 | 118 | |
5300a9b3 | 119 | freezer->state |= CGROUP_FREEZER_ONLINE; |
ef9fe980 TH |
120 | |
121 | if (parent && (parent->state & CGROUP_FREEZING)) { | |
122 | freezer->state |= CGROUP_FREEZING_PARENT | CGROUP_FROZEN; | |
f0cc7492 | 123 | static_branch_inc_cpuslocked(&freezer_active); |
ef9fe980 TH |
124 | } |
125 | ||
e5ced8eb | 126 | mutex_unlock(&freezer_mutex); |
f0cc7492 | 127 | cpus_read_unlock(); |
b1929db4 | 128 | return 0; |
5300a9b3 TH |
129 | } |
130 | ||
131 | /** | |
eb95419b TH |
132 | * freezer_css_offline - initiate destruction of a freezer css |
133 | * @css: css being destroyed | |
5300a9b3 | 134 | * |
f71bfbe1 | 135 | * @css is going away. Mark it dead and decrement freezer_active if |
eb95419b | 136 | * it was holding one. |
5300a9b3 | 137 | */ |
eb95419b | 138 | static void freezer_css_offline(struct cgroup_subsys_state *css) |
5300a9b3 | 139 | { |
eb95419b | 140 | struct freezer *freezer = css_freezer(css); |
5300a9b3 | 141 | |
f0cc7492 | 142 | cpus_read_lock(); |
e5ced8eb | 143 | mutex_lock(&freezer_mutex); |
5300a9b3 | 144 | |
d6a2fe13 | 145 | if (freezer->state & CGROUP_FREEZING) |
f0cc7492 | 146 | static_branch_dec_cpuslocked(&freezer_active); |
5300a9b3 TH |
147 | |
148 | freezer->state = 0; | |
149 | ||
e5ced8eb | 150 | mutex_unlock(&freezer_mutex); |
f0cc7492 | 151 | cpus_read_unlock(); |
5300a9b3 TH |
152 | } |
153 | ||
eb95419b | 154 | static void freezer_css_free(struct cgroup_subsys_state *css) |
5300a9b3 | 155 | { |
eb95419b | 156 | kfree(css_freezer(css)); |
dc52ddc0 MH |
157 | } |
158 | ||
957a4eea | 159 | /* |
ead5c473 TH |
160 | * Tasks can be migrated into a different freezer anytime regardless of its |
161 | * current state. freezer_attach() is responsible for making new tasks | |
162 | * conform to the current state. | |
163 | * | |
164 | * Freezer state changes and task migration are synchronized via | |
165 | * @freezer->lock. freezer_attach() makes the new tasks conform to the | |
166 | * current state and all following state changes can see the new tasks. | |
957a4eea | 167 | */ |
1f7dd3e5 | 168 | static void freezer_attach(struct cgroup_taskset *tset) |
dc52ddc0 | 169 | { |
bb9d97b6 | 170 | struct task_struct *task; |
1f7dd3e5 | 171 | struct cgroup_subsys_state *new_css; |
957a4eea | 172 | |
e5ced8eb | 173 | mutex_lock(&freezer_mutex); |
8755ade6 | 174 | |
80a6a2cf | 175 | /* |
eb95419b | 176 | * Make the new tasks conform to the current state of @new_css. |
8755ade6 TH |
177 | * For simplicity, when migrating any task to a FROZEN cgroup, we |
178 | * revert it to FREEZING and let update_if_frozen() determine the | |
179 | * correct state later. | |
180 | * | |
eb95419b | 181 | * Tasks in @tset are on @new_css but may not conform to its |
8755ade6 TH |
182 | * current state before executing the following - !frozen tasks may |
183 | * be visible in a FROZEN cgroup and frozen tasks in a THAWED one. | |
80a6a2cf | 184 | */ |
1f7dd3e5 | 185 | cgroup_taskset_for_each(task, new_css, tset) { |
599c963a TH |
186 | struct freezer *freezer = css_freezer(new_css); |
187 | ||
d6a2fe13 | 188 | if (!(freezer->state & CGROUP_FREEZING)) { |
8755ade6 TH |
189 | __thaw_task(task); |
190 | } else { | |
191 | freeze_task(task); | |
f5d39b02 | 192 | |
599c963a TH |
193 | /* clear FROZEN and propagate upwards */ |
194 | while (freezer && (freezer->state & CGROUP_FROZEN)) { | |
195 | freezer->state &= ~CGROUP_FROZEN; | |
196 | freezer = parent_freezer(freezer); | |
197 | } | |
8755ade6 TH |
198 | } |
199 | } | |
dc52ddc0 | 200 | |
e5ced8eb | 201 | mutex_unlock(&freezer_mutex); |
f780bdb7 BB |
202 | } |
203 | ||
a60bed29 TH |
204 | /** |
205 | * freezer_fork - cgroup post fork callback | |
206 | * @task: a task which has just been forked | |
207 | * | |
208 | * @task has just been created and should conform to the current state of | |
209 | * the cgroup_freezer it belongs to. This function may race against | |
210 | * freezer_attach(). Losing to freezer_attach() means that we don't have | |
211 | * to do anything as freezer_attach() will put @task into the appropriate | |
212 | * state. | |
213 | */ | |
b53202e6 | 214 | static void freezer_fork(struct task_struct *task) |
dc52ddc0 MH |
215 | { |
216 | struct freezer *freezer; | |
217 | ||
3b1b3f6e | 218 | /* |
a60bed29 TH |
219 | * The root cgroup is non-freezable, so we can skip locking the |
220 | * freezer. This is safe regardless of race with task migration. | |
221 | * If we didn't race or won, skipping is obviously the right thing | |
222 | * to do. If we lost and root is the new cgroup, noop is still the | |
223 | * right thing to do. | |
3b1b3f6e | 224 | */ |
e5ced8eb TH |
225 | if (task_css_is_root(task, freezer_cgrp_id)) |
226 | return; | |
3b1b3f6e | 227 | |
e5ced8eb TH |
228 | mutex_lock(&freezer_mutex); |
229 | rcu_read_lock(); | |
230 | ||
231 | freezer = task_freezer(task); | |
232 | if (freezer->state & CGROUP_FREEZING) | |
839e3407 | 233 | freeze_task(task); |
e5ced8eb | 234 | |
5edee61e | 235 | rcu_read_unlock(); |
e5ced8eb | 236 | mutex_unlock(&freezer_mutex); |
dc52ddc0 MH |
237 | } |
238 | ||
ef9fe980 TH |
239 | /** |
240 | * update_if_frozen - update whether a cgroup finished freezing | |
182446d0 | 241 | * @css: css of interest |
ef9fe980 TH |
242 | * |
243 | * Once FREEZING is initiated, transition to FROZEN is lazily updated by | |
244 | * calling this function. If the current state is FREEZING but not FROZEN, | |
245 | * this function checks whether all tasks of this cgroup and the descendant | |
246 | * cgroups finished freezing and, if so, sets FROZEN. | |
247 | * | |
248 | * The caller is responsible for grabbing RCU read lock and calling | |
249 | * update_if_frozen() on all descendants prior to invoking this function. | |
b4d18311 TH |
250 | * |
251 | * Task states and freezer state might disagree while tasks are being | |
182446d0 | 252 | * migrated into or out of @css, so we can't verify task states against |
ead5c473 | 253 | * @freezer state here. See freezer_attach() for details. |
dc52ddc0 | 254 | */ |
182446d0 | 255 | static void update_if_frozen(struct cgroup_subsys_state *css) |
dc52ddc0 | 256 | { |
182446d0 | 257 | struct freezer *freezer = css_freezer(css); |
492eb21b | 258 | struct cgroup_subsys_state *pos; |
72ec7029 | 259 | struct css_task_iter it; |
dc52ddc0 | 260 | struct task_struct *task; |
b4d18311 | 261 | |
e5ced8eb | 262 | lockdep_assert_held(&freezer_mutex); |
ef9fe980 | 263 | |
d6a2fe13 TH |
264 | if (!(freezer->state & CGROUP_FREEZING) || |
265 | (freezer->state & CGROUP_FROZEN)) | |
e5ced8eb | 266 | return; |
ef9fe980 TH |
267 | |
268 | /* are all (live) children frozen? */ | |
e5ced8eb | 269 | rcu_read_lock(); |
492eb21b TH |
270 | css_for_each_child(pos, css) { |
271 | struct freezer *child = css_freezer(pos); | |
dc52ddc0 | 272 | |
ef9fe980 | 273 | if ((child->state & CGROUP_FREEZER_ONLINE) && |
36e9d2eb TH |
274 | !(child->state & CGROUP_FROZEN)) { |
275 | rcu_read_unlock(); | |
e5ced8eb | 276 | return; |
36e9d2eb | 277 | } |
ef9fe980 | 278 | } |
e5ced8eb | 279 | rcu_read_unlock(); |
ef9fe980 TH |
280 | |
281 | /* are all tasks frozen? */ | |
bc2fb7ed | 282 | css_task_iter_start(css, 0, &it); |
b4d18311 | 283 | |
72ec7029 | 284 | while ((task = css_task_iter_next(&it))) { |
f5d39b02 PZ |
285 | if (freezing(task) && !frozen(task)) |
286 | goto out_iter_end; | |
dc52ddc0 MH |
287 | } |
288 | ||
d6a2fe13 | 289 | freezer->state |= CGROUP_FROZEN; |
ef9fe980 | 290 | out_iter_end: |
72ec7029 | 291 | css_task_iter_end(&it); |
dc52ddc0 MH |
292 | } |
293 | ||
2da8ca82 | 294 | static int freezer_read(struct seq_file *m, void *v) |
dc52ddc0 | 295 | { |
2da8ca82 | 296 | struct cgroup_subsys_state *css = seq_css(m), *pos; |
dc52ddc0 | 297 | |
e5ced8eb | 298 | mutex_lock(&freezer_mutex); |
ef9fe980 | 299 | rcu_read_lock(); |
dc52ddc0 | 300 | |
ef9fe980 | 301 | /* update states bottom-up */ |
e5ced8eb | 302 | css_for_each_descendant_post(pos, css) { |
ec903c0c | 303 | if (!css_tryget_online(pos)) |
e5ced8eb TH |
304 | continue; |
305 | rcu_read_unlock(); | |
306 | ||
492eb21b | 307 | update_if_frozen(pos); |
ef9fe980 | 308 | |
e5ced8eb TH |
309 | rcu_read_lock(); |
310 | css_put(pos); | |
311 | } | |
312 | ||
ef9fe980 | 313 | rcu_read_unlock(); |
e5ced8eb | 314 | mutex_unlock(&freezer_mutex); |
ef9fe980 | 315 | |
182446d0 | 316 | seq_puts(m, freezer_state_strs(css_freezer(css)->state)); |
dc52ddc0 MH |
317 | seq_putc(m, '\n'); |
318 | return 0; | |
319 | } | |
320 | ||
bcd66c89 | 321 | static void freeze_cgroup(struct freezer *freezer) |
dc52ddc0 | 322 | { |
72ec7029 | 323 | struct css_task_iter it; |
dc52ddc0 | 324 | struct task_struct *task; |
dc52ddc0 | 325 | |
bc2fb7ed | 326 | css_task_iter_start(&freezer->css, 0, &it); |
72ec7029 | 327 | while ((task = css_task_iter_next(&it))) |
51f246ed | 328 | freeze_task(task); |
72ec7029 | 329 | css_task_iter_end(&it); |
dc52ddc0 MH |
330 | } |
331 | ||
bcd66c89 | 332 | static void unfreeze_cgroup(struct freezer *freezer) |
dc52ddc0 | 333 | { |
72ec7029 | 334 | struct css_task_iter it; |
dc52ddc0 MH |
335 | struct task_struct *task; |
336 | ||
bc2fb7ed | 337 | css_task_iter_start(&freezer->css, 0, &it); |
72ec7029 | 338 | while ((task = css_task_iter_next(&it))) |
a5be2d0d | 339 | __thaw_task(task); |
72ec7029 | 340 | css_task_iter_end(&it); |
dc52ddc0 MH |
341 | } |
342 | ||
04a4ec32 TH |
343 | /** |
344 | * freezer_apply_state - apply state change to a single cgroup_freezer | |
345 | * @freezer: freezer to apply state change to | |
346 | * @freeze: whether to freeze or unfreeze | |
a2252180 TH |
347 | * @state: CGROUP_FREEZING_* flag to set or clear |
348 | * | |
349 | * Set or clear @state on @cgroup according to @freeze, and perform | |
350 | * freezing or thawing as necessary. | |
04a4ec32 | 351 | */ |
a2252180 TH |
352 | static void freezer_apply_state(struct freezer *freezer, bool freeze, |
353 | unsigned int state) | |
dc52ddc0 | 354 | { |
ead5c473 | 355 | /* also synchronizes against task migration, see freezer_attach() */ |
e5ced8eb | 356 | lockdep_assert_held(&freezer_mutex); |
51308ee5 | 357 | |
5300a9b3 TH |
358 | if (!(freezer->state & CGROUP_FREEZER_ONLINE)) |
359 | return; | |
360 | ||
04a4ec32 | 361 | if (freeze) { |
d6a2fe13 | 362 | if (!(freezer->state & CGROUP_FREEZING)) |
57dcd64c | 363 | static_branch_inc_cpuslocked(&freezer_active); |
a2252180 | 364 | freezer->state |= state; |
bcd66c89 | 365 | freeze_cgroup(freezer); |
04a4ec32 | 366 | } else { |
a2252180 TH |
367 | bool was_freezing = freezer->state & CGROUP_FREEZING; |
368 | ||
369 | freezer->state &= ~state; | |
370 | ||
371 | if (!(freezer->state & CGROUP_FREEZING)) { | |
a2252180 | 372 | freezer->state &= ~CGROUP_FROZEN; |
f5d39b02 | 373 | if (was_freezing) |
57dcd64c | 374 | static_branch_dec_cpuslocked(&freezer_active); |
a2252180 TH |
375 | unfreeze_cgroup(freezer); |
376 | } | |
dc52ddc0 | 377 | } |
04a4ec32 | 378 | } |
22b4e111 | 379 | |
04a4ec32 TH |
380 | /** |
381 | * freezer_change_state - change the freezing state of a cgroup_freezer | |
382 | * @freezer: freezer of interest | |
383 | * @freeze: whether to freeze or thaw | |
384 | * | |
ef9fe980 TH |
385 | * Freeze or thaw @freezer according to @freeze. The operations are |
386 | * recursive - all descendants of @freezer will be affected. | |
04a4ec32 TH |
387 | */ |
388 | static void freezer_change_state(struct freezer *freezer, bool freeze) | |
389 | { | |
492eb21b | 390 | struct cgroup_subsys_state *pos; |
ef9fe980 | 391 | |
57dcd64c | 392 | cpus_read_lock(); |
ef9fe980 TH |
393 | /* |
394 | * Update all its descendants in pre-order traversal. Each | |
395 | * descendant will try to inherit its parent's FREEZING state as | |
396 | * CGROUP_FREEZING_PARENT. | |
397 | */ | |
e5ced8eb | 398 | mutex_lock(&freezer_mutex); |
ef9fe980 | 399 | rcu_read_lock(); |
492eb21b TH |
400 | css_for_each_descendant_pre(pos, &freezer->css) { |
401 | struct freezer *pos_f = css_freezer(pos); | |
ef9fe980 TH |
402 | struct freezer *parent = parent_freezer(pos_f); |
403 | ||
ec903c0c | 404 | if (!css_tryget_online(pos)) |
e5ced8eb TH |
405 | continue; |
406 | rcu_read_unlock(); | |
bd8815a6 | 407 | |
e5ced8eb | 408 | if (pos_f == freezer) |
bd8815a6 TH |
409 | freezer_apply_state(pos_f, freeze, |
410 | CGROUP_FREEZING_SELF); | |
e5ced8eb | 411 | else |
bd8815a6 TH |
412 | freezer_apply_state(pos_f, |
413 | parent->state & CGROUP_FREEZING, | |
414 | CGROUP_FREEZING_PARENT); | |
bd8815a6 | 415 | |
e5ced8eb TH |
416 | rcu_read_lock(); |
417 | css_put(pos); | |
ef9fe980 TH |
418 | } |
419 | rcu_read_unlock(); | |
e5ced8eb | 420 | mutex_unlock(&freezer_mutex); |
57dcd64c | 421 | cpus_read_unlock(); |
dc52ddc0 MH |
422 | } |
423 | ||
451af504 TH |
424 | static ssize_t freezer_write(struct kernfs_open_file *of, |
425 | char *buf, size_t nbytes, loff_t off) | |
dc52ddc0 | 426 | { |
04a4ec32 | 427 | bool freeze; |
dc52ddc0 | 428 | |
451af504 TH |
429 | buf = strstrip(buf); |
430 | ||
431 | if (strcmp(buf, freezer_state_strs(0)) == 0) | |
04a4ec32 | 432 | freeze = false; |
451af504 | 433 | else if (strcmp(buf, freezer_state_strs(CGROUP_FROZEN)) == 0) |
04a4ec32 | 434 | freeze = true; |
dc52ddc0 | 435 | else |
3b1b3f6e | 436 | return -EINVAL; |
dc52ddc0 | 437 | |
451af504 TH |
438 | freezer_change_state(css_freezer(of_css(of)), freeze); |
439 | return nbytes; | |
dc52ddc0 MH |
440 | } |
441 | ||
182446d0 TH |
442 | static u64 freezer_self_freezing_read(struct cgroup_subsys_state *css, |
443 | struct cftype *cft) | |
a2252180 | 444 | { |
182446d0 | 445 | struct freezer *freezer = css_freezer(css); |
a2252180 TH |
446 | |
447 | return (bool)(freezer->state & CGROUP_FREEZING_SELF); | |
448 | } | |
449 | ||
182446d0 TH |
450 | static u64 freezer_parent_freezing_read(struct cgroup_subsys_state *css, |
451 | struct cftype *cft) | |
a2252180 | 452 | { |
182446d0 | 453 | struct freezer *freezer = css_freezer(css); |
a2252180 TH |
454 | |
455 | return (bool)(freezer->state & CGROUP_FREEZING_PARENT); | |
456 | } | |
457 | ||
dc52ddc0 MH |
458 | static struct cftype files[] = { |
459 | { | |
460 | .name = "state", | |
4baf6e33 | 461 | .flags = CFTYPE_NOT_ON_ROOT, |
2da8ca82 | 462 | .seq_show = freezer_read, |
451af504 | 463 | .write = freezer_write, |
dc52ddc0 | 464 | }, |
a2252180 TH |
465 | { |
466 | .name = "self_freezing", | |
467 | .flags = CFTYPE_NOT_ON_ROOT, | |
468 | .read_u64 = freezer_self_freezing_read, | |
469 | }, | |
470 | { | |
471 | .name = "parent_freezing", | |
472 | .flags = CFTYPE_NOT_ON_ROOT, | |
473 | .read_u64 = freezer_parent_freezing_read, | |
474 | }, | |
4baf6e33 | 475 | { } /* terminate */ |
dc52ddc0 MH |
476 | }; |
477 | ||
073219e9 | 478 | struct cgroup_subsys freezer_cgrp_subsys = { |
92fb9748 TH |
479 | .css_alloc = freezer_css_alloc, |
480 | .css_online = freezer_css_online, | |
481 | .css_offline = freezer_css_offline, | |
482 | .css_free = freezer_css_free, | |
8755ade6 | 483 | .attach = freezer_attach, |
dc52ddc0 | 484 | .fork = freezer_fork, |
5577964e | 485 | .legacy_cftypes = files, |
dc52ddc0 | 486 | }; |