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Commit 593be07a authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
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[PATCH] file: kill unnecessary timer in fdtable_defer 



free_fdtable_rc() schedules timer to reschedule fddef->wq if
schedule_work() on it returns 0.  However, schedule_work() guarantees that
the target work is executed at least once after the scheduling regardless
of its return value.  0 return simply means that the work was already
pending and thus no further action was required.

Another problem is that it used contant '5' as @expires argument to
mod_timer().

Kill unnecessary fddef->timer.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e59e2ae2

fs/file.c

+2 −27
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ 
struct fdtable_defer {

	spinlock_t lock;

	struct work_struct wq;

	struct timer_list timer;

	struct fdtable *next;

};
@@ -75,22 +74,6 @@ static void __free_fdtable(struct fdtable *fdt) 
	kfree(fdt);

}



static void fdtable_timer(unsigned long data)

{

	struct fdtable_defer *fddef = (struct fdtable_defer *)data;



	spin_lock(&fddef->lock);

	/*

	 * If someone already emptied the queue return.

	 */

	if (!fddef->next)

		goto out;

	if (!schedule_work(&fddef->wq))

		mod_timer(&fddef->timer, 5);

out:

	spin_unlock(&fddef->lock);

}



static void free_fdtable_work(struct work_struct *work)

{

	struct fdtable_defer *f =
@@ -144,13 +127,8 @@ static void free_fdtable_rcu(struct rcu_head *rcu) 
		spin_lock(&fddef->lock);

		fdt->next = fddef->next;

		fddef->next = fdt;

		/*

		 * vmallocs are handled from the workqueue context.

		 * If the per-cpu workqueue is running, then we

		 * defer work scheduling through a timer.

		 */

		if (!schedule_work(&fddef->wq))

			mod_timer(&fddef->timer, 5);

		/* vmallocs are handled from the workqueue context */

		schedule_work(&fddef->wq);

		spin_unlock(&fddef->lock);

		put_cpu_var(fdtable_defer_list);

	}
@@ -354,9 +332,6 @@ static void __devinit fdtable_defer_list_init(int cpu) 
	struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);

	spin_lock_init(&fddef->lock);

	INIT_WORK(&fddef->wq, free_fdtable_work);

	init_timer(&fddef->timer);

	fddef->timer.data = (unsigned long)fddef;

	fddef->timer.function = fdtable_timer;

	fddef->next = NULL;

}