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[PATCH] swsusp: Untangle freeze_processes

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Move the loop from freeze_processes() to a separate function and call it
independently for user space processes and kernel threads so that the order
of freezing tasks is clearly visible.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Rafael J. Wysocki 2006-12-06 20:34:40 -08:00 committed by Linus Torvalds
parent a9b6f562f1
commit 11b2ce2ba9
1 changed files with 54 additions and 30 deletions
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84
kernel/power/process.c
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@ -86,24 +86,23 @@ static inline int is_user_space(struct task_struct *p)
return p->mm && !(p->flags & PF_BORROWED_MM);
}
/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
static unsigned int try_to_freeze_tasks(int freeze_user_space)
{
int todo, nr_user, user_frozen;
unsigned long start_time;
struct task_struct *g, *p;
unsigned long end_time;
unsigned int todo;
printk("Stopping tasks... ");
start_time = jiffies;
user_frozen = 0;
end_time = jiffies + TIMEOUT;
do {
nr_user = todo = 0;
todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
if (frozen(p))
continue;
if (p->state == TASK_TRACED &&
(frozen(p->parent) ||
p->parent->state == TASK_STOPPED)) {
@ -111,51 +110,76 @@ int freeze_processes(void)
continue;
}
if (is_user_space(p)) {
if (!freeze_user_space)
continue;
/* Freeze the task unless there is a vfork
* completion pending
*/
if (!p->vfork_done)
freeze_process(p);
nr_user++;
} else {
/* Freeze only if the user space is frozen */
if (user_frozen)
freeze_process(p);
todo++;
if (freeze_user_space)
continue;
freeze_process(p);
}
todo++;
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
todo += nr_user;
if (!user_frozen && !nr_user) {
sys_sync();
start_time = jiffies;
}
user_frozen = !nr_user;
yield(); /* Yield is okay here */
if (todo && time_after(jiffies, start_time + TIMEOUT))
if (todo && time_after(jiffies, end_time))
break;
} while(todo);
} while (todo);
/* This does not unfreeze processes that are already frozen
* (we have slightly ugly calling convention in that respect,
* and caller must call thaw_processes() if something fails),
* but it cleans up leftover PF_FREEZE requests.
*/
if (todo) {
/* This does not unfreeze processes that are already frozen
* (we have slightly ugly calling convention in that respect,
* and caller must call thaw_processes() if something fails),
* but it cleans up leftover PF_FREEZE requests.
*/
printk("\n");
printk(KERN_ERR "Stopping tasks timed out "
"after %d seconds (%d tasks remaining):\n",
TIMEOUT / HZ, todo);
printk(KERN_ERR "Stopping %s timed out after %d seconds "
"(%d tasks refusing to freeze):\n",
freeze_user_space ? "user space processes" :
"kernel threads",
TIMEOUT / HZ, todo);
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (is_user_space(p) == !freeze_user_space)
continue;
if (freezeable(p) && !frozen(p))
printk(KERN_ERR " %s\n", p->comm);
cancel_freezing(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
return todo;
}
return todo;
}
/**
* freeze_processes - tell processes to enter the refrigerator
*
* Returns 0 on success, or the number of processes that didn't freeze,
* although they were told to.
*/
int freeze_processes(void)
{
unsigned int nr_unfrozen;
printk("Stopping tasks ... ");
nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
if (nr_unfrozen)
return nr_unfrozen;
sys_sync();
nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
if (nr_unfrozen)
return nr_unfrozen;
printk("done.\n");
BUG_ON(in_atomic());
return 0;