]>
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> | |
b17b0153 | 15 | #include <linux/sched/debug.h> |
29930025 | 16 | #include <linux/sched/task.h> |
02aaeb9b | 17 | #include <linux/syscalls.h> |
7dfb7103 | 18 | #include <linux/freezer.h> |
be404f02 | 19 | #include <linux/delay.h> |
a0a1a5fd | 20 | #include <linux/workqueue.h> |
1e73203c | 21 | #include <linux/kmod.h> |
bb3632c6 | 22 | #include <trace/events/power.h> |
1da177e4 LT |
23 | |
24 | /* | |
25 | * Timeout for stopping processes | |
26 | */ | |
957d1282 | 27 | unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; |
1da177e4 | 28 | |
839e3407 | 29 | static int try_to_freeze_tasks(bool user_only) |
1da177e4 | 30 | { |
1da177e4 | 31 | struct task_struct *g, *p; |
11b2ce2b RW |
32 | unsigned long end_time; |
33 | unsigned int todo; | |
a0a1a5fd | 34 | bool wq_busy = false; |
f7b382b9 | 35 | ktime_t start, end, elapsed; |
18ad0c62 | 36 | unsigned int elapsed_msecs; |
dbeeec5f | 37 | bool wakeup = false; |
18ad0c62 | 38 | int sleep_usecs = USEC_PER_MSEC; |
438e2ce6 | 39 | |
f7b382b9 | 40 | start = ktime_get_boottime(); |
3e1d1d28 | 41 | |
957d1282 | 42 | end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs); |
a0a1a5fd | 43 | |
839e3407 | 44 | if (!user_only) |
a0a1a5fd TH |
45 | freeze_workqueues_begin(); |
46 | ||
be404f02 | 47 | while (true) { |
11b2ce2b | 48 | todo = 0; |
1da177e4 | 49 | read_lock(&tasklist_lock); |
a28e785a | 50 | for_each_process_thread(g, p) { |
839e3407 | 51 | if (p == current || !freeze_task(p)) |
d5d8c597 RW |
52 | continue; |
53 | ||
5d8f72b5 | 54 | if (!freezer_should_skip(p)) |
ba96a0c8 | 55 | todo++; |
a28e785a | 56 | } |
1da177e4 | 57 | read_unlock(&tasklist_lock); |
a0a1a5fd | 58 | |
839e3407 | 59 | if (!user_only) { |
a0a1a5fd TH |
60 | wq_busy = freeze_workqueues_busy(); |
61 | todo += wq_busy; | |
62 | } | |
63 | ||
be404f02 | 64 | if (!todo || time_after(jiffies, end_time)) |
6161b2ce | 65 | break; |
be404f02 | 66 | |
a2867e08 | 67 | if (pm_wakeup_pending()) { |
dbeeec5f RW |
68 | wakeup = true; |
69 | break; | |
70 | } | |
71 | ||
be404f02 TH |
72 | /* |
73 | * We need to retry, but first give the freezing tasks some | |
18ad0c62 CC |
74 | * time to enter the refrigerator. Start with an initial |
75 | * 1 ms sleep followed by exponential backoff until 8 ms. | |
be404f02 | 76 | */ |
18ad0c62 CC |
77 | usleep_range(sleep_usecs / 2, sleep_usecs); |
78 | if (sleep_usecs < 8 * USEC_PER_MSEC) | |
79 | sleep_usecs *= 2; | |
be404f02 | 80 | } |
3e1d1d28 | 81 | |
f7b382b9 AJ |
82 | end = ktime_get_boottime(); |
83 | elapsed = ktime_sub(end, start); | |
84 | elapsed_msecs = ktime_to_ms(elapsed); | |
438e2ce6 | 85 | |
6161b2ce | 86 | if (todo) { |
35536ae1 MH |
87 | pr_cont("\n"); |
88 | pr_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 | ||
7b776af6 RL |
94 | if (wq_busy) |
95 | show_workqueue_state(); | |
96 | ||
6c83b481 RW |
97 | if (!wakeup) { |
98 | read_lock(&tasklist_lock); | |
a28e785a | 99 | for_each_process_thread(g, p) { |
6c83b481 RW |
100 | if (p != current && !freezer_should_skip(p) |
101 | && freezing(p) && !frozen(p)) | |
102 | sched_show_task(p); | |
a28e785a | 103 | } |
6c83b481 RW |
104 | read_unlock(&tasklist_lock); |
105 | } | |
438e2ce6 | 106 | } else { |
35536ae1 | 107 | pr_cont("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, |
18ad0c62 | 108 | elapsed_msecs % 1000); |
6161b2ce PM |
109 | } |
110 | ||
e7cd8a72 | 111 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
112 | } |
113 | ||
114 | /** | |
2aede851 | 115 | * freeze_processes - Signal user space processes to enter the refrigerator. |
2b44c4db CC |
116 | * The current thread will not be frozen. The same process that calls |
117 | * freeze_processes must later call thaw_processes. | |
03afed8b TH |
118 | * |
119 | * On success, returns 0. On failure, -errno and system is fully thawed. | |
11b2ce2b RW |
120 | */ |
121 | int freeze_processes(void) | |
122 | { | |
e7cd8a72 | 123 | int error; |
11b2ce2b | 124 | |
247bc037 | 125 | error = __usermodehelper_disable(UMH_FREEZING); |
1e73203c RW |
126 | if (error) |
127 | return error; | |
128 | ||
2b44c4db CC |
129 | /* Make sure this task doesn't get frozen */ |
130 | current->flags |= PF_SUSPEND_TASK; | |
131 | ||
a3201227 TH |
132 | if (!pm_freezing) |
133 | atomic_inc(&system_freezing_cnt); | |
134 | ||
f3b7eaae | 135 | pm_wakeup_clear(); |
35536ae1 | 136 | pr_info("Freezing user space processes ... "); |
a3201227 | 137 | pm_freezing = true; |
ebb12db5 | 138 | error = try_to_freeze_tasks(true); |
2aede851 | 139 | if (!error) { |
247bc037 | 140 | __usermodehelper_set_disable_depth(UMH_DISABLED); |
c32b3cbe | 141 | pr_cont("done."); |
2aede851 | 142 | } |
35536ae1 | 143 | pr_cont("\n"); |
2aede851 RW |
144 | BUG_ON(in_atomic()); |
145 | ||
c32b3cbe MH |
146 | /* |
147 | * Now that the whole userspace is frozen we need to disbale | |
148 | * the OOM killer to disallow any further interference with | |
7d2e7a22 MH |
149 | * killable tasks. There is no guarantee oom victims will |
150 | * ever reach a point they go away we have to wait with a timeout. | |
c32b3cbe | 151 | */ |
7d2e7a22 | 152 | if (!error && !oom_killer_disable(msecs_to_jiffies(freeze_timeout_msecs))) |
c32b3cbe MH |
153 | error = -EBUSY; |
154 | ||
03afed8b TH |
155 | if (error) |
156 | thaw_processes(); | |
2aede851 RW |
157 | return error; |
158 | } | |
159 | ||
160 | /** | |
161 | * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator. | |
03afed8b | 162 | * |
379e0be8 SB |
163 | * On success, returns 0. On failure, -errno and only the kernel threads are |
164 | * thawed, so as to give a chance to the caller to do additional cleanups | |
165 | * (if any) before thawing the userspace tasks. So, it is the responsibility | |
166 | * of the caller to thaw the userspace tasks, when the time is right. | |
2aede851 RW |
167 | */ |
168 | int freeze_kernel_threads(void) | |
169 | { | |
170 | int error; | |
11b2ce2b | 171 | |
35536ae1 MH |
172 | pr_info("Freezing remaining freezable tasks ... "); |
173 | ||
a3201227 | 174 | pm_nosig_freezing = true; |
ebb12db5 | 175 | error = try_to_freeze_tasks(false); |
2aede851 | 176 | if (!error) |
35536ae1 | 177 | pr_cont("done."); |
7f33d49a | 178 | |
35536ae1 | 179 | pr_cont("\n"); |
2aede851 | 180 | BUG_ON(in_atomic()); |
7f33d49a | 181 | |
03afed8b | 182 | if (error) |
379e0be8 | 183 | thaw_kernel_threads(); |
b842ee57 | 184 | return error; |
1da177e4 LT |
185 | } |
186 | ||
6cd8dedc | 187 | void thaw_processes(void) |
1da177e4 LT |
188 | { |
189 | struct task_struct *g, *p; | |
2b44c4db | 190 | struct task_struct *curr = current; |
1da177e4 | 191 | |
bb3632c6 | 192 | trace_suspend_resume(TPS("thaw_processes"), 0, true); |
a3201227 TH |
193 | if (pm_freezing) |
194 | atomic_dec(&system_freezing_cnt); | |
195 | pm_freezing = false; | |
196 | pm_nosig_freezing = false; | |
197 | ||
6cd8dedc TH |
198 | oom_killer_enable(); |
199 | ||
35536ae1 | 200 | pr_info("Restarting tasks ... "); |
6cd8dedc | 201 | |
4320f6b1 | 202 | __usermodehelper_set_disable_depth(UMH_FREEZING); |
6cd8dedc TH |
203 | thaw_workqueues(); |
204 | ||
1da177e4 | 205 | read_lock(&tasklist_lock); |
a28e785a | 206 | for_each_process_thread(g, p) { |
2b44c4db CC |
207 | /* No other threads should have PF_SUSPEND_TASK set */ |
208 | WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK)); | |
a5be2d0d | 209 | __thaw_task(p); |
a28e785a | 210 | } |
1da177e4 | 211 | read_unlock(&tasklist_lock); |
7f33d49a | 212 | |
2b44c4db CC |
213 | WARN_ON(!(curr->flags & PF_SUSPEND_TASK)); |
214 | curr->flags &= ~PF_SUSPEND_TASK; | |
215 | ||
1e73203c RW |
216 | usermodehelper_enable(); |
217 | ||
1da177e4 | 218 | schedule(); |
35536ae1 | 219 | pr_cont("done.\n"); |
bb3632c6 | 220 | trace_suspend_resume(TPS("thaw_processes"), 0, false); |
1da177e4 LT |
221 | } |
222 | ||
181e9bde RW |
223 | void thaw_kernel_threads(void) |
224 | { | |
225 | struct task_struct *g, *p; | |
226 | ||
227 | pm_nosig_freezing = false; | |
35536ae1 | 228 | pr_info("Restarting kernel threads ... "); |
181e9bde RW |
229 | |
230 | thaw_workqueues(); | |
231 | ||
232 | read_lock(&tasklist_lock); | |
a28e785a | 233 | for_each_process_thread(g, p) { |
181e9bde RW |
234 | if (p->flags & (PF_KTHREAD | PF_WQ_WORKER)) |
235 | __thaw_task(p); | |
a28e785a | 236 | } |
181e9bde RW |
237 | read_unlock(&tasklist_lock); |
238 | ||
239 | schedule(); | |
35536ae1 | 240 | pr_cont("done.\n"); |
181e9bde | 241 | } |