2 * drivers/power/process.c - Functions for starting/stopping processes on
5 * Originally from swsusp.
11 #include <linux/smp_lock.h>
12 #include <linux/interrupt.h>
13 #include <linux/suspend.h>
14 #include <linux/module.h>
17 * Timeout for stopping processes
19 #define TIMEOUT (6 * HZ)
22 static inline int freezeable(struct task_struct * p)
25 (p->flags & PF_NOFREEZE) ||
26 (p->state == TASK_ZOMBIE) ||
27 (p->state == TASK_DEAD) ||
28 (p->state == TASK_STOPPED))
33 /* Refrigerator is place where frozen processes are stored :-). */
34 void refrigerator(unsigned long flag)
36 /* Hmm, should we be allowed to suspend when there are realtime
39 save = current->state;
40 current->state = TASK_UNINTERRUPTIBLE;
41 pr_debug("%s entered refrigerator\n", current->comm);
43 current->flags &= ~PF_FREEZE;
45 spin_lock_irq(¤t->sighand->siglock);
46 recalc_sigpending(); /* We sent fake signal, clean it up */
47 spin_unlock_irq(¤t->sighand->siglock);
49 current->flags |= PF_FROZEN;
50 while (current->flags & PF_FROZEN)
52 pr_debug("%s left refrigerator\n", current->comm);
53 current->state = save;
56 /* 0 = success, else # of processes that we failed to stop */
57 int freeze_processes(void)
60 unsigned long start_time;
61 struct task_struct *g, *p;
63 printk( "Stopping tasks: " );
67 read_lock(&tasklist_lock);
68 do_each_thread(g, p) {
72 if ((p->flags & PF_FROZEN) ||
73 (p->state == TASK_STOPPED))
76 /* FIXME: smp problem here: we may not access other process' flags
78 p->flags |= PF_FREEZE;
79 spin_lock_irqsave(&p->sighand->siglock, flags);
81 spin_unlock_irqrestore(&p->sighand->siglock, flags);
83 } while_each_thread(g, p);
84 read_unlock(&tasklist_lock);
85 yield(); /* Yield is okay here */
86 if (time_after(jiffies, start_time + TIMEOUT)) {
88 printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
98 void thaw_processes(void)
100 struct task_struct *g, *p;
102 printk( "Restarting tasks..." );
103 read_lock(&tasklist_lock);
104 do_each_thread(g, p) {
107 if (p->flags & PF_FROZEN) {
108 p->flags &= ~PF_FROZEN;
111 printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
113 } while_each_thread(g, p);
115 read_unlock(&tasklist_lock);
120 EXPORT_SYMBOL(refrigerator);