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_csecs
;
37 do_gettimeofday(&start
);
39 end_time
= jiffies
+ msecs_to_jiffies(freeze_timeout_msecs
);
42 freeze_workqueues_begin();
46 read_lock(&tasklist_lock
);
47 do_each_thread(g
, p
) {
48 if (p
== current
|| !freeze_task(p
))
51 if (!freezer_should_skip(p
))
53 } while_each_thread(g
, p
);
54 read_unlock(&tasklist_lock
);
57 wq_busy
= freeze_workqueues_busy();
61 if (!todo
|| time_after(jiffies
, end_time
))
64 if (pm_wakeup_pending()) {
70 * We need to retry, but first give the freezing tasks some
71 * time to enter the refrigerator.
76 do_gettimeofday(&end
);
77 elapsed_csecs64
= timeval_to_ns(&end
) - timeval_to_ns(&start
);
78 do_div(elapsed_csecs64
, NSEC_PER_SEC
/ 100);
79 elapsed_csecs
= elapsed_csecs64
;
83 printk(KERN_ERR
"Freezing of tasks %s after %d.%02d seconds "
84 "(%d tasks refusing to freeze, wq_busy=%d):\n",
85 wakeup
? "aborted" : "failed",
86 elapsed_csecs
/ 100, elapsed_csecs
% 100,
87 todo
- wq_busy
, wq_busy
);
90 read_lock(&tasklist_lock
);
91 do_each_thread(g
, p
) {
92 if (p
!= current
&& !freezer_should_skip(p
)
93 && freezing(p
) && !frozen(p
))
95 } while_each_thread(g
, p
);
96 read_unlock(&tasklist_lock
);
99 printk("(elapsed %d.%02d seconds) ", elapsed_csecs
/ 100,
100 elapsed_csecs
% 100);
103 return todo
? -EBUSY
: 0;
107 * freeze_processes - Signal user space processes to enter the refrigerator.
109 * On success, returns 0. On failure, -errno and system is fully thawed.
111 int freeze_processes(void)
115 error
= __usermodehelper_disable(UMH_FREEZING
);
120 atomic_inc(&system_freezing_cnt
);
122 printk("Freezing user space processes ... ");
124 error
= try_to_freeze_tasks(true);
127 __usermodehelper_set_disable_depth(UMH_DISABLED
);
128 oom_killer_disable();
139 * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
141 * On success, returns 0. On failure, -errno and only the kernel threads are
142 * thawed, so as to give a chance to the caller to do additional cleanups
143 * (if any) before thawing the userspace tasks. So, it is the responsibility
144 * of the caller to thaw the userspace tasks, when the time is right.
146 int freeze_kernel_threads(void)
150 printk("Freezing remaining freezable tasks ... ");
151 pm_nosig_freezing
= true;
152 error
= try_to_freeze_tasks(false);
160 thaw_kernel_threads();
164 void thaw_processes(void)
166 struct task_struct
*g
, *p
;
169 atomic_dec(&system_freezing_cnt
);
171 pm_nosig_freezing
= false;
175 printk("Restarting tasks ... ");
179 read_lock(&tasklist_lock
);
180 do_each_thread(g
, p
) {
182 } while_each_thread(g
, p
);
183 read_unlock(&tasklist_lock
);
185 usermodehelper_enable();
191 void thaw_kernel_threads(void)
193 struct task_struct
*g
, *p
;
195 pm_nosig_freezing
= false;
196 printk("Restarting kernel threads ... ");
200 read_lock(&tasklist_lock
);
201 do_each_thread(g
, p
) {
202 if (p
->flags
& (PF_KTHREAD
| PF_WQ_WORKER
))
204 } while_each_thread(g
, p
);
205 read_unlock(&tasklist_lock
);