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Commit 02aaeb9b authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
Browse files

[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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarPavel Machek <pavel@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6e1819d6

kernel/power/disk.c

+0 −1
Original line number Diff line number Diff line
@@ -72,7 +72,6 @@ static int prepare_processes(void) 
	int error;



	pm_prepare_console();

	sys_sync();

	disable_nonboot_cpus();



	if (freeze_processes()) {

kernel/power/process.c

+46 −15
Original line number Diff line number Diff line
@@ -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);

		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)) {

			printk( "\n" );

			printk(KERN_ERR " stopping tasks timed out (%d tasks remaining)\n", todo );

		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;

	}

kernel/power/user.c

+0 −1
Original line number Diff line number Diff line
@@ -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();