/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
{
	int todo;
	unsigned long start_time;
	struct task_struct *g, *p;
	unsigned long flags;

	printk( "Stopping tasks: " );
	start_time = jiffies;
	do {
		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);
			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 failed (%d tasks remaining)\n", todo );
			break;
		}
	} 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) {
		read_lock(&tasklist_lock);
		do_each_thread(g, p)
			if (freezing(p)) {
				pr_debug("  clean up: %s\n", p->comm);
				p->flags &= ~PF_FREEZE;
				spin_lock_irqsave(&p->sighand->siglock, flags);
				recalc_sigpending_tsk(p);
				spin_unlock_irqrestore(&p->sighand->siglock, flags);
			}
		while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		return todo;
	}

	printk( "|\n" );
	BUG_ON(in_atomic());
	return 0;
}
Ejemplo n.º 2
0
/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
{
	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 {
		nr_user = todo = 0;
		read_lock(&tasklist_lock);
		do_each_thread(g, p) {
			if (!freezeable(p))
				continue;
			if (frozen(p))
				continue;
			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))
			break;
	} 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) {
		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) {
			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;
				spin_lock_irqsave(&p->sighand->siglock, flags);
				recalc_sigpending_tsk(p);
				spin_unlock_irqrestore(&p->sighand->siglock, flags);
			}
		} while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		return todo;
	}

	printk( "|\n" );
	BUG_ON(in_atomic());
	return 0;
}