2 * drivers/power/process.c - Functions for starting/stopping processes on
5 * Originally from swsusp.
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>
22 * Timeout for stopping processes
24 unsigned int __read_mostly freeze_timeout_msecs
= 20 * MSEC_PER_SEC
;
26 static int try_to_freeze_tasks(bool user_only
)
28 struct task_struct
*g
, *p
;
29 unsigned long end_time
;
32 struct timeval start
, end
;
34 unsigned int elapsed_msecs
;
36 int sleep_usecs
= USEC_PER_MSEC
;
38 do_gettimeofday(&start
);
40 end_time
= jiffies
+ msecs_to_jiffies(freeze_timeout_msecs
);
43 freeze_workqueues_begin();
47 read_lock(&tasklist_lock
);
48 do_each_thread(g
, p
) {
49 if (p
== current
|| !freeze_task(p
))
52 if (!freezer_should_skip(p
))
54 } while_each_thread(g
, p
);
55 read_unlock(&tasklist_lock
);
58 wq_busy
= freeze_workqueues_busy();
62 if (!todo
|| time_after(jiffies
, end_time
))
65 if (pm_wakeup_pending()) {
71 * We need to retry, but first give the freezing tasks some
72 * time to enter the refrigerator. Start with an initial
73 * 1 ms sleep followed by exponential backoff until 8 ms.
75 usleep_range(sleep_usecs
/ 2, sleep_usecs
);
76 if (sleep_usecs
< 8 * USEC_PER_MSEC
)
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
;
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
);
94 read_lock(&tasklist_lock
);
95 do_each_thread(g
, p
) {
96 if (p
!= current
&& !freezer_should_skip(p
)
97 && freezing(p
) && !frozen(p
))
99 } while_each_thread(g
, p
);
100 read_unlock(&tasklist_lock
);
103 printk("(elapsed %d.%03d seconds) ", elapsed_msecs
/ 1000,
104 elapsed_msecs
% 1000);
107 return todo
? -EBUSY
: 0;
111 * freeze_processes - Signal user space processes to enter the refrigerator.
113 * On success, returns 0. On failure, -errno and system is fully thawed.
115 int freeze_processes(void)
119 error
= __usermodehelper_disable(UMH_FREEZING
);
124 atomic_inc(&system_freezing_cnt
);
126 printk("Freezing user space processes ... ");
128 error
= try_to_freeze_tasks(true);
131 __usermodehelper_set_disable_depth(UMH_DISABLED
);
132 oom_killer_disable();
141 EXPORT_SYMBOL_GPL(freeze_processes
);
144 * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
146 * On success, returns 0. On failure, -errno and only the kernel threads are
147 * thawed, so as to give a chance to the caller to do additional cleanups
148 * (if any) before thawing the userspace tasks. So, it is the responsibility
149 * of the caller to thaw the userspace tasks, when the time is right.
151 int freeze_kernel_threads(void)
155 printk("Freezing remaining freezable tasks ... ");
156 pm_nosig_freezing
= true;
157 error
= try_to_freeze_tasks(false);
165 thaw_kernel_threads();
168 EXPORT_SYMBOL_GPL(freeze_kernel_threads
);
170 void thaw_processes(void)
172 struct task_struct
*g
, *p
;
175 atomic_dec(&system_freezing_cnt
);
177 pm_nosig_freezing
= false;
181 printk("Restarting tasks ... ");
183 __usermodehelper_set_disable_depth(UMH_FREEZING
);
186 read_lock(&tasklist_lock
);
187 do_each_thread(g
, p
) {
188 BUG_ON(!virt_addr_valid(next_task(g
)));
190 } while_each_thread(g
, p
);
191 read_unlock(&tasklist_lock
);
193 usermodehelper_enable();
198 EXPORT_SYMBOL_GPL(thaw_processes
);
200 void thaw_kernel_threads(void)
202 struct task_struct
*g
, *p
;
204 pm_nosig_freezing
= false;
205 printk("Restarting kernel threads ... ");
209 read_lock(&tasklist_lock
);
210 do_each_thread(g
, p
) {
211 if (p
->flags
& (PF_KTHREAD
| PF_WQ_WORKER
))
213 } while_each_thread(g
, p
);
214 read_unlock(&tasklist_lock
);
219 EXPORT_SYMBOL_GPL(thaw_kernel_threads
);