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CommitLineData
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
LT
11#include <linux/interrupt.h>
12#include <linux/suspend.h>
13#include <linux/module.h>
02aaeb9b 14#include <linux/syscalls.h>
7dfb7103 15#include <linux/freezer.h>
1da177e4
LT
16
17/*
18 * Timeout for stopping processes
19 */
02aaeb9b 20#define TIMEOUT (20 * HZ)
1da177e4 21
1da177e4
LT
22static inline int freezeable(struct task_struct * p)
23{
1065d130 24 if ((p == current) ||
1da177e4 25 (p->flags & PF_NOFREEZE) ||
1065d130 26 (p->exit_state != 0))
1da177e4
LT
27 return 0;
28 return 1;
29}
30
ebb12db5 31static int try_to_freeze_tasks(bool sig_only)
1da177e4 32{
1da177e4 33 struct task_struct *g, *p;
11b2ce2b
RW
34 unsigned long end_time;
35 unsigned int todo;
438e2ce6 36 struct timeval start, end;
f0af566d 37 u64 elapsed_csecs64;
438e2ce6
RW
38 unsigned int elapsed_csecs;
39
40 do_gettimeofday(&start);
3e1d1d28 41
11b2ce2b 42 end_time = jiffies + TIMEOUT;
1da177e4 43 do {
11b2ce2b 44 todo = 0;
1da177e4
LT
45 read_lock(&tasklist_lock);
46 do_each_thread(g, p) {
0c1eecfb 47 if (frozen(p) || !freezeable(p))
1da177e4 48 continue;
11b2ce2b 49
ebb12db5 50 if (!freeze_task(p, sig_only))
d5d8c597
RW
51 continue;
52
13b1c3d4
RM
53 /*
54 * Now that we've done set_freeze_flag, don't
55 * perturb a task in TASK_STOPPED or TASK_TRACED.
56 * It is "frozen enough". If the task does wake
57 * up, it will immediately call try_to_freeze.
58 */
59 if (!task_is_stopped_or_traced(p) &&
60 !freezer_should_skip(p))
ba96a0c8 61 todo++;
1da177e4
LT
62 } while_each_thread(g, p);
63 read_unlock(&tasklist_lock);
64 yield(); /* Yield is okay here */
c2cf7d87 65 if (time_after(jiffies, end_time))
6161b2ce 66 break;
11b2ce2b 67 } while (todo);
3e1d1d28 68
438e2ce6
RW
69 do_gettimeofday(&end);
70 elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
71 do_div(elapsed_csecs64, NSEC_PER_SEC / 100);
72 elapsed_csecs = elapsed_csecs64;
73
6161b2ce 74 if (todo) {
11b2ce2b
RW
75 /* This does not unfreeze processes that are already frozen
76 * (we have slightly ugly calling convention in that respect,
77 * and caller must call thaw_processes() if something fails),
78 * but it cleans up leftover PF_FREEZE requests.
79 */
14b5b7cf 80 printk("\n");
438e2ce6 81 printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
11b2ce2b 82 "(%d tasks refusing to freeze):\n",
438e2ce6 83 elapsed_csecs / 100, elapsed_csecs % 100, todo);
328616e3 84 show_state();
6161b2ce 85 read_lock(&tasklist_lock);
02aaeb9b 86 do_each_thread(g, p) {
33e1c288 87 task_lock(p);
0c1eecfb 88 if (freezing(p) && !freezer_should_skip(p))
14b5b7cf 89 printk(KERN_ERR " %s\n", p->comm);
a7ef7878 90 cancel_freezing(p);
33e1c288 91 task_unlock(p);
02aaeb9b 92 } while_each_thread(g, p);
6161b2ce 93 read_unlock(&tasklist_lock);
438e2ce6
RW
94 } else {
95 printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
96 elapsed_csecs % 100);
6161b2ce
PM
97 }
98
e7cd8a72 99 return todo ? -EBUSY : 0;
11b2ce2b
RW
100}
101
102/**
103 * freeze_processes - tell processes to enter the refrigerator
11b2ce2b
RW
104 */
105int freeze_processes(void)
106{
e7cd8a72 107 int error;
11b2ce2b 108
b842ee57 109 printk("Freezing user space processes ... ");
ebb12db5 110 error = try_to_freeze_tasks(true);
e7cd8a72 111 if (error)
b842ee57
RW
112 goto Exit;
113 printk("done.\n");
11b2ce2b 114
b842ee57 115 printk("Freezing remaining freezable tasks ... ");
ebb12db5 116 error = try_to_freeze_tasks(false);
e7cd8a72 117 if (error)
b842ee57
RW
118 goto Exit;
119 printk("done.");
7f33d49a
RW
120
121 oom_killer_disable();
b842ee57 122 Exit:
1da177e4 123 BUG_ON(in_atomic());
b842ee57 124 printk("\n");
7f33d49a 125
b842ee57 126 return error;
1da177e4
LT
127}
128
ebb12db5 129static void thaw_tasks(bool nosig_only)
1da177e4
LT
130{
131 struct task_struct *g, *p;
132
1da177e4 133 read_lock(&tasklist_lock);
a9b6f562
RW
134 do_each_thread(g, p) {
135 if (!freezeable(p))
136 continue;
ff39593a 137
ebb12db5 138 if (nosig_only && should_send_signal(p))
a9b6f562 139 continue;
1da177e4 140
5a06915c
MH
141 if (cgroup_frozen(p))
142 continue;
143
ba96a0c8 144 thaw_process(p);
a9b6f562 145 } while_each_thread(g, p);
1da177e4 146 read_unlock(&tasklist_lock);
a9b6f562
RW
147}
148
149void thaw_processes(void)
150{
7f33d49a
RW
151 oom_killer_enable();
152
a9b6f562 153 printk("Restarting tasks ... ");
ebb12db5
RW
154 thaw_tasks(true);
155 thaw_tasks(false);
1da177e4 156 schedule();
14b5b7cf 157 printk("done.\n");
1da177e4
LT
158}
159