Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * drivers/power/process.c - Functions for starting/stopping processes on | |
3 | * suspend transitions. | |
4 | * | |
5 | * Originally from swsusp. | |
6 | */ | |
7 | ||
8 | ||
9 | #undef DEBUG | |
10 | ||
1da177e4 | 11 | #include <linux/interrupt.h> |
1a8670a2 | 12 | #include <linux/oom.h> |
1da177e4 LT |
13 | #include <linux/suspend.h> |
14 | #include <linux/module.h> | |
02aaeb9b | 15 | #include <linux/syscalls.h> |
7dfb7103 | 16 | #include <linux/freezer.h> |
be404f02 | 17 | #include <linux/delay.h> |
a0a1a5fd | 18 | #include <linux/workqueue.h> |
1e73203c | 19 | #include <linux/kmod.h> |
bb3632c6 | 20 | #include <trace/events/power.h> |
1da177e4 LT |
21 | |
22 | /* | |
23 | * Timeout for stopping processes | |
24 | */ | |
957d1282 | 25 | unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; |
1da177e4 | 26 | |
839e3407 | 27 | static int try_to_freeze_tasks(bool user_only) |
1da177e4 | 28 | { |
1da177e4 | 29 | struct task_struct *g, *p; |
11b2ce2b RW |
30 | unsigned long end_time; |
31 | unsigned int todo; | |
a0a1a5fd | 32 | bool wq_busy = false; |
438e2ce6 | 33 | struct timeval start, end; |
18ad0c62 CC |
34 | u64 elapsed_msecs64; |
35 | unsigned int elapsed_msecs; | |
dbeeec5f | 36 | bool wakeup = false; |
18ad0c62 | 37 | int sleep_usecs = USEC_PER_MSEC; |
438e2ce6 RW |
38 | |
39 | do_gettimeofday(&start); | |
3e1d1d28 | 40 | |
957d1282 | 41 | end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs); |
a0a1a5fd | 42 | |
839e3407 | 43 | if (!user_only) |
a0a1a5fd TH |
44 | freeze_workqueues_begin(); |
45 | ||
be404f02 | 46 | while (true) { |
11b2ce2b | 47 | todo = 0; |
1da177e4 | 48 | read_lock(&tasklist_lock); |
a28e785a | 49 | for_each_process_thread(g, p) { |
839e3407 | 50 | if (p == current || !freeze_task(p)) |
d5d8c597 RW |
51 | continue; |
52 | ||
5d8f72b5 | 53 | if (!freezer_should_skip(p)) |
ba96a0c8 | 54 | todo++; |
a28e785a | 55 | } |
1da177e4 | 56 | read_unlock(&tasklist_lock); |
a0a1a5fd | 57 | |
839e3407 | 58 | if (!user_only) { |
a0a1a5fd TH |
59 | wq_busy = freeze_workqueues_busy(); |
60 | todo += wq_busy; | |
61 | } | |
62 | ||
be404f02 | 63 | if (!todo || time_after(jiffies, end_time)) |
6161b2ce | 64 | break; |
be404f02 | 65 | |
a2867e08 | 66 | if (pm_wakeup_pending()) { |
dbeeec5f RW |
67 | wakeup = true; |
68 | break; | |
69 | } | |
70 | ||
be404f02 TH |
71 | /* |
72 | * We need to retry, but first give the freezing tasks some | |
18ad0c62 CC |
73 | * time to enter the refrigerator. Start with an initial |
74 | * 1 ms sleep followed by exponential backoff until 8 ms. | |
be404f02 | 75 | */ |
18ad0c62 CC |
76 | usleep_range(sleep_usecs / 2, sleep_usecs); |
77 | if (sleep_usecs < 8 * USEC_PER_MSEC) | |
78 | sleep_usecs *= 2; | |
be404f02 | 79 | } |
3e1d1d28 | 80 | |
438e2ce6 | 81 | do_gettimeofday(&end); |
18ad0c62 CC |
82 | elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); |
83 | do_div(elapsed_msecs64, NSEC_PER_MSEC); | |
84 | elapsed_msecs = elapsed_msecs64; | |
438e2ce6 | 85 | |
6161b2ce | 86 | if (todo) { |
14b5b7cf | 87 | printk("\n"); |
18ad0c62 | 88 | printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds " |
a0a1a5fd | 89 | "(%d tasks refusing to freeze, wq_busy=%d):\n", |
dbeeec5f | 90 | wakeup ? "aborted" : "failed", |
18ad0c62 | 91 | elapsed_msecs / 1000, elapsed_msecs % 1000, |
a0a1a5fd TH |
92 | todo - wq_busy, wq_busy); |
93 | ||
6c83b481 RW |
94 | if (!wakeup) { |
95 | read_lock(&tasklist_lock); | |
a28e785a | 96 | for_each_process_thread(g, p) { |
6c83b481 RW |
97 | if (p != current && !freezer_should_skip(p) |
98 | && freezing(p) && !frozen(p)) | |
99 | sched_show_task(p); | |
a28e785a | 100 | } |
6c83b481 RW |
101 | read_unlock(&tasklist_lock); |
102 | } | |
438e2ce6 | 103 | } else { |
18ad0c62 CC |
104 | printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, |
105 | elapsed_msecs % 1000); | |
6161b2ce PM |
106 | } |
107 | ||
e7cd8a72 | 108 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
109 | } |
110 | ||
71be2114 RW |
111 | static bool __check_frozen_processes(void) |
112 | { | |
113 | struct task_struct *g, *p; | |
114 | ||
115 | for_each_process_thread(g, p) | |
116 | if (p != current && !freezer_should_skip(p) && !frozen(p)) | |
117 | return false; | |
118 | ||
119 | return true; | |
120 | } | |
121 | ||
5695be14 MH |
122 | /* |
123 | * Returns true if all freezable tasks (except for current) are frozen already | |
124 | */ | |
125 | static bool check_frozen_processes(void) | |
126 | { | |
71be2114 | 127 | bool ret; |
5695be14 MH |
128 | |
129 | read_lock(&tasklist_lock); | |
71be2114 | 130 | ret = __check_frozen_processes(); |
5695be14 | 131 | read_unlock(&tasklist_lock); |
5695be14 MH |
132 | return ret; |
133 | } | |
134 | ||
11b2ce2b | 135 | /** |
2aede851 | 136 | * freeze_processes - Signal user space processes to enter the refrigerator. |
2b44c4db CC |
137 | * The current thread will not be frozen. The same process that calls |
138 | * freeze_processes must later call thaw_processes. | |
03afed8b TH |
139 | * |
140 | * On success, returns 0. On failure, -errno and system is fully thawed. | |
11b2ce2b RW |
141 | */ |
142 | int freeze_processes(void) | |
143 | { | |
e7cd8a72 | 144 | int error; |
5695be14 | 145 | int oom_kills_saved; |
11b2ce2b | 146 | |
247bc037 | 147 | error = __usermodehelper_disable(UMH_FREEZING); |
1e73203c RW |
148 | if (error) |
149 | return error; | |
150 | ||
2b44c4db CC |
151 | /* Make sure this task doesn't get frozen */ |
152 | current->flags |= PF_SUSPEND_TASK; | |
153 | ||
a3201227 TH |
154 | if (!pm_freezing) |
155 | atomic_inc(&system_freezing_cnt); | |
156 | ||
068765ba | 157 | pm_wakeup_clear(); |
b842ee57 | 158 | printk("Freezing user space processes ... "); |
a3201227 | 159 | pm_freezing = true; |
5695be14 | 160 | oom_kills_saved = oom_kills_count(); |
ebb12db5 | 161 | error = try_to_freeze_tasks(true); |
2aede851 | 162 | if (!error) { |
247bc037 | 163 | __usermodehelper_set_disable_depth(UMH_DISABLED); |
2aede851 | 164 | oom_killer_disable(); |
5695be14 MH |
165 | |
166 | /* | |
167 | * There might have been an OOM kill while we were | |
168 | * freezing tasks and the killed task might be still | |
169 | * on the way out so we have to double check for race. | |
170 | */ | |
171 | if (oom_kills_count() != oom_kills_saved && | |
71be2114 | 172 | !check_frozen_processes()) { |
5695be14 MH |
173 | __usermodehelper_set_disable_depth(UMH_ENABLED); |
174 | printk("OOM in progress."); | |
175 | error = -EBUSY; | |
71be2114 RW |
176 | } else { |
177 | printk("done."); | |
5695be14 | 178 | } |
2aede851 RW |
179 | } |
180 | printk("\n"); | |
181 | BUG_ON(in_atomic()); | |
182 | ||
03afed8b TH |
183 | if (error) |
184 | thaw_processes(); | |
2aede851 RW |
185 | return error; |
186 | } | |
187 | ||
188 | /** | |
189 | * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator. | |
03afed8b | 190 | * |
379e0be8 SB |
191 | * On success, returns 0. On failure, -errno and only the kernel threads are |
192 | * thawed, so as to give a chance to the caller to do additional cleanups | |
193 | * (if any) before thawing the userspace tasks. So, it is the responsibility | |
194 | * of the caller to thaw the userspace tasks, when the time is right. | |
2aede851 RW |
195 | */ |
196 | int freeze_kernel_threads(void) | |
197 | { | |
198 | int error; | |
11b2ce2b | 199 | |
b842ee57 | 200 | printk("Freezing remaining freezable tasks ... "); |
a3201227 | 201 | pm_nosig_freezing = true; |
ebb12db5 | 202 | error = try_to_freeze_tasks(false); |
2aede851 RW |
203 | if (!error) |
204 | printk("done."); | |
7f33d49a | 205 | |
b842ee57 | 206 | printk("\n"); |
2aede851 | 207 | BUG_ON(in_atomic()); |
7f33d49a | 208 | |
03afed8b | 209 | if (error) |
379e0be8 | 210 | thaw_kernel_threads(); |
b842ee57 | 211 | return error; |
1da177e4 LT |
212 | } |
213 | ||
6cd8dedc | 214 | void thaw_processes(void) |
1da177e4 LT |
215 | { |
216 | struct task_struct *g, *p; | |
2b44c4db | 217 | struct task_struct *curr = current; |
1da177e4 | 218 | |
bb3632c6 | 219 | trace_suspend_resume(TPS("thaw_processes"), 0, true); |
a3201227 TH |
220 | if (pm_freezing) |
221 | atomic_dec(&system_freezing_cnt); | |
222 | pm_freezing = false; | |
223 | pm_nosig_freezing = false; | |
224 | ||
6cd8dedc TH |
225 | oom_killer_enable(); |
226 | ||
227 | printk("Restarting tasks ... "); | |
228 | ||
4320f6b1 | 229 | __usermodehelper_set_disable_depth(UMH_FREEZING); |
6cd8dedc TH |
230 | thaw_workqueues(); |
231 | ||
1da177e4 | 232 | read_lock(&tasklist_lock); |
a28e785a | 233 | for_each_process_thread(g, p) { |
2b44c4db CC |
234 | /* No other threads should have PF_SUSPEND_TASK set */ |
235 | WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK)); | |
a5be2d0d | 236 | __thaw_task(p); |
a28e785a | 237 | } |
1da177e4 | 238 | read_unlock(&tasklist_lock); |
7f33d49a | 239 | |
2b44c4db CC |
240 | WARN_ON(!(curr->flags & PF_SUSPEND_TASK)); |
241 | curr->flags &= ~PF_SUSPEND_TASK; | |
242 | ||
1e73203c RW |
243 | usermodehelper_enable(); |
244 | ||
1da177e4 | 245 | schedule(); |
14b5b7cf | 246 | printk("done.\n"); |
bb3632c6 | 247 | trace_suspend_resume(TPS("thaw_processes"), 0, false); |
1da177e4 LT |
248 | } |
249 | ||
181e9bde RW |
250 | void thaw_kernel_threads(void) |
251 | { | |
252 | struct task_struct *g, *p; | |
253 | ||
254 | pm_nosig_freezing = false; | |
255 | printk("Restarting kernel threads ... "); | |
256 | ||
257 | thaw_workqueues(); | |
258 | ||
259 | read_lock(&tasklist_lock); | |
a28e785a | 260 | for_each_process_thread(g, p) { |
181e9bde RW |
261 | if (p->flags & (PF_KTHREAD | PF_WQ_WORKER)) |
262 | __thaw_task(p); | |
a28e785a | 263 | } |
181e9bde RW |
264 | read_unlock(&tasklist_lock); |
265 | ||
266 | schedule(); | |
267 | printk("done.\n"); | |
268 | } |