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Commit | Line | Data |
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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> |
02aaeb9b | 16 | #include <linux/syscalls.h> |
7dfb7103 | 17 | #include <linux/freezer.h> |
be404f02 | 18 | #include <linux/delay.h> |
a0a1a5fd | 19 | #include <linux/workqueue.h> |
1e73203c | 20 | #include <linux/kmod.h> |
bb3632c6 | 21 | #include <trace/events/power.h> |
1da177e4 LT |
22 | |
23 | /* | |
24 | * Timeout for stopping processes | |
25 | */ | |
957d1282 | 26 | unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; |
1da177e4 | 27 | |
839e3407 | 28 | static int try_to_freeze_tasks(bool user_only) |
1da177e4 | 29 | { |
1da177e4 | 30 | struct task_struct *g, *p; |
11b2ce2b RW |
31 | unsigned long end_time; |
32 | unsigned int todo; | |
a0a1a5fd | 33 | bool wq_busy = false; |
f7b382b9 | 34 | ktime_t start, end, elapsed; |
18ad0c62 | 35 | unsigned int elapsed_msecs; |
dbeeec5f | 36 | bool wakeup = false; |
18ad0c62 | 37 | int sleep_usecs = USEC_PER_MSEC; |
438e2ce6 | 38 | |
f7b382b9 | 39 | start = ktime_get_boottime(); |
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 | |
f7b382b9 AJ |
81 | end = ktime_get_boottime(); |
82 | elapsed = ktime_sub(end, start); | |
83 | elapsed_msecs = ktime_to_ms(elapsed); | |
438e2ce6 | 84 | |
6161b2ce | 85 | if (todo) { |
35536ae1 MH |
86 | pr_cont("\n"); |
87 | pr_err("Freezing of tasks %s after %d.%03d seconds " | |
a0a1a5fd | 88 | "(%d tasks refusing to freeze, wq_busy=%d):\n", |
dbeeec5f | 89 | wakeup ? "aborted" : "failed", |
18ad0c62 | 90 | elapsed_msecs / 1000, elapsed_msecs % 1000, |
a0a1a5fd TH |
91 | todo - wq_busy, wq_busy); |
92 | ||
7b776af6 RL |
93 | if (wq_busy) |
94 | show_workqueue_state(); | |
95 | ||
6c83b481 RW |
96 | if (!wakeup) { |
97 | read_lock(&tasklist_lock); | |
a28e785a | 98 | for_each_process_thread(g, p) { |
6c83b481 RW |
99 | if (p != current && !freezer_should_skip(p) |
100 | && freezing(p) && !frozen(p)) | |
101 | sched_show_task(p); | |
a28e785a | 102 | } |
6c83b481 RW |
103 | read_unlock(&tasklist_lock); |
104 | } | |
438e2ce6 | 105 | } else { |
35536ae1 | 106 | pr_cont("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, |
18ad0c62 | 107 | elapsed_msecs % 1000); |
6161b2ce PM |
108 | } |
109 | ||
e7cd8a72 | 110 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
111 | } |
112 | ||
113 | /** | |
2aede851 | 114 | * freeze_processes - Signal user space processes to enter the refrigerator. |
2b44c4db CC |
115 | * The current thread will not be frozen. The same process that calls |
116 | * freeze_processes must later call thaw_processes. | |
03afed8b TH |
117 | * |
118 | * On success, returns 0. On failure, -errno and system is fully thawed. | |
11b2ce2b RW |
119 | */ |
120 | int freeze_processes(void) | |
121 | { | |
e7cd8a72 | 122 | int error; |
11b2ce2b | 123 | |
247bc037 | 124 | error = __usermodehelper_disable(UMH_FREEZING); |
1e73203c RW |
125 | if (error) |
126 | return error; | |
127 | ||
2b44c4db CC |
128 | /* Make sure this task doesn't get frozen */ |
129 | current->flags |= PF_SUSPEND_TASK; | |
130 | ||
a3201227 TH |
131 | if (!pm_freezing) |
132 | atomic_inc(&system_freezing_cnt); | |
133 | ||
068765ba | 134 | pm_wakeup_clear(); |
35536ae1 | 135 | pr_info("Freezing user space processes ... "); |
a3201227 | 136 | pm_freezing = true; |
ebb12db5 | 137 | error = try_to_freeze_tasks(true); |
2aede851 | 138 | if (!error) { |
247bc037 | 139 | __usermodehelper_set_disable_depth(UMH_DISABLED); |
c32b3cbe | 140 | pr_cont("done."); |
2aede851 | 141 | } |
35536ae1 | 142 | pr_cont("\n"); |
2aede851 RW |
143 | BUG_ON(in_atomic()); |
144 | ||
c32b3cbe MH |
145 | /* |
146 | * Now that the whole userspace is frozen we need to disbale | |
147 | * the OOM killer to disallow any further interference with | |
7d2e7a22 MH |
148 | * killable tasks. There is no guarantee oom victims will |
149 | * ever reach a point they go away we have to wait with a timeout. | |
c32b3cbe | 150 | */ |
7d2e7a22 | 151 | if (!error && !oom_killer_disable(msecs_to_jiffies(freeze_timeout_msecs))) |
c32b3cbe MH |
152 | error = -EBUSY; |
153 | ||
03afed8b TH |
154 | if (error) |
155 | thaw_processes(); | |
2aede851 RW |
156 | return error; |
157 | } | |
158 | ||
159 | /** | |
160 | * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator. | |
03afed8b | 161 | * |
379e0be8 SB |
162 | * On success, returns 0. On failure, -errno and only the kernel threads are |
163 | * thawed, so as to give a chance to the caller to do additional cleanups | |
164 | * (if any) before thawing the userspace tasks. So, it is the responsibility | |
165 | * of the caller to thaw the userspace tasks, when the time is right. | |
2aede851 RW |
166 | */ |
167 | int freeze_kernel_threads(void) | |
168 | { | |
169 | int error; | |
11b2ce2b | 170 | |
35536ae1 MH |
171 | pr_info("Freezing remaining freezable tasks ... "); |
172 | ||
a3201227 | 173 | pm_nosig_freezing = true; |
ebb12db5 | 174 | error = try_to_freeze_tasks(false); |
2aede851 | 175 | if (!error) |
35536ae1 | 176 | pr_cont("done."); |
7f33d49a | 177 | |
35536ae1 | 178 | pr_cont("\n"); |
2aede851 | 179 | BUG_ON(in_atomic()); |
7f33d49a | 180 | |
03afed8b | 181 | if (error) |
379e0be8 | 182 | thaw_kernel_threads(); |
b842ee57 | 183 | return error; |
1da177e4 LT |
184 | } |
185 | ||
6cd8dedc | 186 | void thaw_processes(void) |
1da177e4 LT |
187 | { |
188 | struct task_struct *g, *p; | |
2b44c4db | 189 | struct task_struct *curr = current; |
1da177e4 | 190 | |
bb3632c6 | 191 | trace_suspend_resume(TPS("thaw_processes"), 0, true); |
a3201227 TH |
192 | if (pm_freezing) |
193 | atomic_dec(&system_freezing_cnt); | |
194 | pm_freezing = false; | |
195 | pm_nosig_freezing = false; | |
196 | ||
6cd8dedc TH |
197 | oom_killer_enable(); |
198 | ||
35536ae1 | 199 | pr_info("Restarting tasks ... "); |
6cd8dedc | 200 | |
4320f6b1 | 201 | __usermodehelper_set_disable_depth(UMH_FREEZING); |
6cd8dedc TH |
202 | thaw_workqueues(); |
203 | ||
1da177e4 | 204 | read_lock(&tasklist_lock); |
a28e785a | 205 | for_each_process_thread(g, p) { |
2b44c4db CC |
206 | /* No other threads should have PF_SUSPEND_TASK set */ |
207 | WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK)); | |
a5be2d0d | 208 | __thaw_task(p); |
a28e785a | 209 | } |
1da177e4 | 210 | read_unlock(&tasklist_lock); |
7f33d49a | 211 | |
2b44c4db CC |
212 | WARN_ON(!(curr->flags & PF_SUSPEND_TASK)); |
213 | curr->flags &= ~PF_SUSPEND_TASK; | |
214 | ||
1e73203c RW |
215 | usermodehelper_enable(); |
216 | ||
1da177e4 | 217 | schedule(); |
35536ae1 | 218 | pr_cont("done.\n"); |
bb3632c6 | 219 | trace_suspend_resume(TPS("thaw_processes"), 0, false); |
1da177e4 LT |
220 | } |
221 | ||
181e9bde RW |
222 | void thaw_kernel_threads(void) |
223 | { | |
224 | struct task_struct *g, *p; | |
225 | ||
226 | pm_nosig_freezing = false; | |
35536ae1 | 227 | pr_info("Restarting kernel threads ... "); |
181e9bde RW |
228 | |
229 | thaw_workqueues(); | |
230 | ||
231 | read_lock(&tasklist_lock); | |
a28e785a | 232 | for_each_process_thread(g, p) { |
181e9bde RW |
233 | if (p->flags & (PF_KTHREAD | PF_WQ_WORKER)) |
234 | __thaw_task(p); | |
a28e785a | 235 | } |
181e9bde RW |
236 | read_unlock(&tasklist_lock); |
237 | ||
238 | schedule(); | |
35536ae1 | 239 | pr_cont("done.\n"); |
181e9bde | 240 | } |