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>
21 * Timeout for stopping processes
23 #define TIMEOUT (20 * HZ)
25 static inline int freezeable(struct task_struct
* p
)
28 (p
->flags
& PF_NOFREEZE
) ||
34 static int try_to_freeze_tasks(bool sig_only
)
36 struct task_struct
*g
, *p
;
37 unsigned long end_time
;
40 struct timeval start
, end
;
42 unsigned int elapsed_csecs
;
45 do_gettimeofday(&start
);
47 end_time
= jiffies
+ TIMEOUT
;
50 freeze_workqueues_begin();
54 read_lock(&tasklist_lock
);
55 do_each_thread(g
, p
) {
56 if (frozen(p
) || !freezeable(p
))
59 if (!freeze_task(p
, sig_only
))
63 * Now that we've done set_freeze_flag, don't
64 * perturb a task in TASK_STOPPED or TASK_TRACED.
65 * It is "frozen enough". If the task does wake
66 * up, it will immediately call try_to_freeze.
68 if (!task_is_stopped_or_traced(p
) &&
69 !freezer_should_skip(p
))
71 } while_each_thread(g
, p
);
72 read_unlock(&tasklist_lock
);
75 wq_busy
= freeze_workqueues_busy();
79 if (!todo
|| time_after(jiffies
, end_time
))
82 if (!pm_check_wakeup_events()) {
88 * We need to retry, but first give the freezing tasks some
89 * time to enter the regrigerator.
94 do_gettimeofday(&end
);
95 elapsed_csecs64
= timeval_to_ns(&end
) - timeval_to_ns(&start
);
96 do_div(elapsed_csecs64
, NSEC_PER_SEC
/ 100);
97 elapsed_csecs
= elapsed_csecs64
;
100 /* This does not unfreeze processes that are already frozen
101 * (we have slightly ugly calling convention in that respect,
102 * and caller must call thaw_processes() if something fails),
103 * but it cleans up leftover PF_FREEZE requests.
106 printk(KERN_ERR
"Freezing of tasks %s after %d.%02d seconds "
107 "(%d tasks refusing to freeze, wq_busy=%d):\n",
108 wakeup
? "aborted" : "failed",
109 elapsed_csecs
/ 100, elapsed_csecs
% 100,
110 todo
- wq_busy
, wq_busy
);
114 read_lock(&tasklist_lock
);
115 do_each_thread(g
, p
) {
117 if (!wakeup
&& freezing(p
) && !freezer_should_skip(p
))
121 } while_each_thread(g
, p
);
122 read_unlock(&tasklist_lock
);
124 printk("(elapsed %d.%02d seconds) ", elapsed_csecs
/ 100,
125 elapsed_csecs
% 100);
128 return todo
? -EBUSY
: 0;
132 * freeze_processes - tell processes to enter the refrigerator
134 int freeze_processes(void)
138 printk("Freezing user space processes ... ");
139 error
= try_to_freeze_tasks(true);
144 printk("Freezing remaining freezable tasks ... ");
145 error
= try_to_freeze_tasks(false);
150 oom_killer_disable();
158 static void thaw_tasks(bool nosig_only
)
160 struct task_struct
*g
, *p
;
162 read_lock(&tasklist_lock
);
163 do_each_thread(g
, p
) {
167 if (nosig_only
&& should_send_signal(p
))
170 if (cgroup_freezing_or_frozen(p
))
174 } while_each_thread(g
, p
);
175 read_unlock(&tasklist_lock
);
178 void thaw_processes(void)
182 printk("Restarting tasks ... ");