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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/power/process.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'kernel/power/process.c')
-rw-r--r--kernel/power/process.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
new file mode 100644
index 000000000000..78d92dc6a1ed
--- /dev/null
+++ b/kernel/power/process.c
@@ -0,0 +1,121 @@
1/*
2 * drivers/power/process.c - Functions for starting/stopping processes on
3 * suspend transitions.
4 *
5 * Originally from swsusp.
6 */
7
8
9#undef DEBUG
10
11#include <linux/smp_lock.h>
12#include <linux/interrupt.h>
13#include <linux/suspend.h>
14#include <linux/module.h>
15
16/*
17 * Timeout for stopping processes
18 */
19#define TIMEOUT (6 * HZ)
20
21
22static inline int freezeable(struct task_struct * p)
23{
24 if ((p == current) ||
25 (p->flags & PF_NOFREEZE) ||
26 (p->exit_state == EXIT_ZOMBIE) ||
27 (p->exit_state == EXIT_DEAD) ||
28 (p->state == TASK_STOPPED) ||
29 (p->state == TASK_TRACED))
30 return 0;
31 return 1;
32}
33
34/* Refrigerator is place where frozen processes are stored :-). */
35void refrigerator(unsigned long flag)
36{
37 /* Hmm, should we be allowed to suspend when there are realtime
38 processes around? */
39 long save;
40 save = current->state;
41 current->state = TASK_UNINTERRUPTIBLE;
42 pr_debug("%s entered refrigerator\n", current->comm);
43 printk("=");
44 current->flags &= ~PF_FREEZE;
45
46 spin_lock_irq(&current->sighand->siglock);
47 recalc_sigpending(); /* We sent fake signal, clean it up */
48 spin_unlock_irq(&current->sighand->siglock);
49
50 current->flags |= PF_FROZEN;
51 while (current->flags & PF_FROZEN)
52 schedule();
53 pr_debug("%s left refrigerator\n", current->comm);
54 current->state = save;
55}
56
57/* 0 = success, else # of processes that we failed to stop */
58int freeze_processes(void)
59{
60 int todo;
61 unsigned long start_time;
62 struct task_struct *g, *p;
63
64 printk( "Stopping tasks: " );
65 start_time = jiffies;
66 do {
67 todo = 0;
68 read_lock(&tasklist_lock);
69 do_each_thread(g, p) {
70 unsigned long flags;
71 if (!freezeable(p))
72 continue;
73 if ((p->flags & PF_FROZEN) ||
74 (p->state == TASK_TRACED) ||
75 (p->state == TASK_STOPPED))
76 continue;
77
78 /* FIXME: smp problem here: we may not access other process' flags
79 without locking */
80 p->flags |= PF_FREEZE;
81 spin_lock_irqsave(&p->sighand->siglock, flags);
82 signal_wake_up(p, 0);
83 spin_unlock_irqrestore(&p->sighand->siglock, flags);
84 todo++;
85 } while_each_thread(g, p);
86 read_unlock(&tasklist_lock);
87 yield(); /* Yield is okay here */
88 if (time_after(jiffies, start_time + TIMEOUT)) {
89 printk( "\n" );
90 printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
91 return todo;
92 }
93 } while(todo);
94
95 printk( "|\n" );
96 BUG_ON(in_atomic());
97 return 0;
98}
99
100void thaw_processes(void)
101{
102 struct task_struct *g, *p;
103
104 printk( "Restarting tasks..." );
105 read_lock(&tasklist_lock);
106 do_each_thread(g, p) {
107 if (!freezeable(p))
108 continue;
109 if (p->flags & PF_FROZEN) {
110 p->flags &= ~PF_FROZEN;
111 wake_up_process(p);
112 } else
113 printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
114 } while_each_thread(g, p);
115
116 read_unlock(&tasklist_lock);
117 schedule();
118 printk( " done\n" );
119}
120
121EXPORT_SYMBOL(refrigerator);