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[PATCH] swsusp: freeze user space processes first 

Allow swsusp to freeze processes successfully under heavy load by freezing
userspace processes before kernel threads.

[Thanks to Nigel Cunningham <nigel@suspend2.net> for suggesting the
way to go.]

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Rafael J. Wysocki 2006-03-23 03:00:04 -08:00 committed by Linus Torvalds
parent 6e1819d615
commit 02aaeb9b95
3 changed files with 47 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
kernel/power/disk.c
View File

@ -72,7 +72,6 @@ static int prepare_processes(void)
int error;
pm_prepare_console();
sys_sync();
disable_nonboot_cpus();
if (freeze_processes()) {

61
kernel/power/process.c
View File

@ -12,11 +12,12 @@
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/module.h>
#include <linux/syscalls.h>
/*
* Timeout for stopping processes
*/
#define TIMEOUT (6 * HZ)
#define TIMEOUT (20 * HZ)
static inline int freezeable(struct task_struct * p)
@ -54,38 +55,62 @@ void refrigerator(void)
current->state = save;
}
static inline void freeze_process(struct task_struct *p)
{
unsigned long flags;
if (!freezing(p)) {
freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
signal_wake_up(p, 0);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
{
int todo;
int todo, nr_user, user_frozen;
unsigned long start_time;
struct task_struct *g, *p;
unsigned long flags;
printk( "Stopping tasks: " );
start_time = jiffies;
user_frozen = 0;
do {
todo = 0;
nr_user = todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
if (frozen(p))
continue;
freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
signal_wake_up(p, 0);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
if (p->mm && !(p->flags & PF_BORROWED_MM)) {
/* The task is a user-space one.
* Freeze it unless there's 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++;
}
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
yield(); /* Yield is okay here */
if (todo && time_after(jiffies, start_time + TIMEOUT)) {
printk( "\n" );
printk(KERN_ERR " stopping tasks timed out (%d tasks remaining)\n", todo );
break;
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))
break;
} while(todo);
/* This does not unfreeze processes that are already frozen
@ -94,8 +119,14 @@ int freeze_processes(void)
* but it cleans up leftover PF_FREEZE requests.
*/
if (todo) {
printk( "\n" );
printk(KERN_ERR " stopping tasks timed out "
"after %d seconds (%d tasks remaining):\n",
TIMEOUT / HZ, todo);
read_lock(&tasklist_lock);
do_each_thread(g, p)
do_each_thread(g, p) {
if (freezeable(p) && !frozen(p))
printk(KERN_ERR " %s\n", p->comm);
if (freezing(p)) {
pr_debug(" clean up: %s\n", p->comm);
p->flags &= ~PF_FREEZE;
@ -103,7 +134,7 @@ int freeze_processes(void)
recalc_sigpending_tsk(p);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
while_each_thread(g, p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
return todo;
}

1
kernel/power/user.c
View File

@ -138,7 +138,6 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
case SNAPSHOT_FREEZE:
if (data->frozen)
break;
sys_sync();
down(&pm_sem);
pm_prepare_console();
disable_nonboot_cpus();