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8
9#undef DEBUG
10
11#include <linux/interrupt.h>
12#include <linux/oom.h>
13#include <linux/suspend.h>
14#include <linux/module.h>
15#include <linux/syscalls.h>
16#include <linux/freezer.h>
17#include <linux/delay.h>
18#include <linux/workqueue.h>
19#include <linux/kmod.h>
20
21
22
23
24unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC;
25
26static int try_to_freeze_tasks(bool user_only)
27{
28 struct task_struct *g, *p;
29 unsigned long end_time;
30 unsigned int todo;
31 bool wq_busy = false;
32 struct timeval start, end;
33 u64 elapsed_msecs64;
34 unsigned int elapsed_msecs;
35 bool wakeup = false;
36 int sleep_usecs = USEC_PER_MSEC;
37
38 do_gettimeofday(&start);
39
40 end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
41
42 if (!user_only)
43 freeze_workqueues_begin();
44
45 while (true) {
46 todo = 0;
47 read_lock(&tasklist_lock);
48 do_each_thread(g, p) {
49 if (p == current || !freeze_task(p))
50 continue;
51
52 if (!freezer_should_skip(p))
53 todo++;
54 } while_each_thread(g, p);
55 read_unlock(&tasklist_lock);
56
57 if (!user_only) {
58 wq_busy = freeze_workqueues_busy();
59 todo += wq_busy;
60 }
61
62 if (!todo || time_after(jiffies, end_time))
63 break;
64
65 if (pm_wakeup_pending()) {
66 wakeup = true;
67 break;
68 }
69
70
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72
73
74
75 usleep_range(sleep_usecs / 2, sleep_usecs);
76 if (sleep_usecs < 8 * USEC_PER_MSEC)
77 sleep_usecs *= 2;
78 }
79
80 do_gettimeofday(&end);
81 elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
82 do_div(elapsed_msecs64, NSEC_PER_MSEC);
83 elapsed_msecs = elapsed_msecs64;
84
85 if (todo) {
86 printk("\n");
87 printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds "
88 "(%d tasks refusing to freeze, wq_busy=%d):\n",
89 wakeup ? "aborted" : "failed",
90 elapsed_msecs / 1000, elapsed_msecs % 1000,
91 todo - wq_busy, wq_busy);
92
93 if (!wakeup) {
94 read_lock(&tasklist_lock);
95 do_each_thread(g, p) {
96 if (p != current && !freezer_should_skip(p)
97 && freezing(p) && !frozen(p))
98 sched_show_task(p);
99 } while_each_thread(g, p);
100 read_unlock(&tasklist_lock);
101 }
102 } else {
103 printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000,
104 elapsed_msecs % 1000);
105 }
106
107 return todo ? -EBUSY : 0;
108}
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115
116
117int freeze_processes(void)
118{
119 int error;
120
121 error = __usermodehelper_disable(UMH_FREEZING);
122 if (error)
123 return error;
124
125
126 current->flags |= PF_SUSPEND_TASK;
127
128 if (!pm_freezing)
129 atomic_inc(&system_freezing_cnt);
130
131 printk("Freezing user space processes ... ");
132 pm_freezing = true;
133 error = try_to_freeze_tasks(true);
134 if (!error) {
135 printk("done.");
136 __usermodehelper_set_disable_depth(UMH_DISABLED);
137 oom_killer_disable();
138 }
139 printk("\n");
140 BUG_ON(in_atomic());
141
142 if (error)
143 thaw_processes();
144 return error;
145}
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153
154
155int freeze_kernel_threads(void)
156{
157 int error;
158
159 printk("Freezing remaining freezable tasks ... ");
160 pm_nosig_freezing = true;
161 error = try_to_freeze_tasks(false);
162 if (!error)
163 printk("done.");
164
165 printk("\n");
166 BUG_ON(in_atomic());
167
168 if (error)
169 thaw_kernel_threads();
170 return error;
171}
172
173void thaw_processes(void)
174{
175 struct task_struct *g, *p;
176 struct task_struct *curr = current;
177
178 if (pm_freezing)
179 atomic_dec(&system_freezing_cnt);
180 pm_freezing = false;
181 pm_nosig_freezing = false;
182
183 oom_killer_enable();
184
185 printk("Restarting tasks ... ");
186
187 thaw_workqueues();
188
189 read_lock(&tasklist_lock);
190 do_each_thread(g, p) {
191
192 WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
193 __thaw_task(p);
194 } while_each_thread(g, p);
195 read_unlock(&tasklist_lock);
196
197 WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
198 curr->flags &= ~PF_SUSPEND_TASK;
199
200 usermodehelper_enable();
201
202 schedule();
203 printk("done.\n");
204}
205
206void thaw_kernel_threads(void)
207{
208 struct task_struct *g, *p;
209
210 pm_nosig_freezing = false;
211 printk("Restarting kernel threads ... ");
212
213 thaw_workqueues();
214
215 read_lock(&tasklist_lock);
216 do_each_thread(g, p) {
217 if (p->flags & (PF_KTHREAD | PF_WQ_WORKER))
218 __thaw_task(p);
219 } while_each_thread(g, p);
220 read_unlock(&tasklist_lock);
221
222 schedule();
223 printk("done.\n");
224}
225