Commit 46a06401 authored by Shaohua Li's avatar Shaohua Li Committed by NeilBrown
Browse files

raid5: raid5d handle stripe in batch way 



Let raid5d handle stripe in batch way to reduce conf->device_lock locking.

Signed-off-by: default avatarShaohua Li <shli@fusionio.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 8811b596

drivers/md/raid5.c

+32 −13
Original line number Diff line number Diff line
@@ -4574,6 +4574,30 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio) 
	return handled;

}



#define MAX_STRIPE_BATCH 8

static int handle_active_stripes(struct r5conf *conf)

{

	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;

	int i, batch_size = 0;



	while (batch_size < MAX_STRIPE_BATCH &&

			(sh = __get_priority_stripe(conf)) != NULL)

		batch[batch_size++] = sh;



	if (batch_size == 0)

		return batch_size;

	spin_unlock_irq(&conf->device_lock);



	for (i = 0; i < batch_size; i++)

		handle_stripe(batch[i]);



	cond_resched();



	spin_lock_irq(&conf->device_lock);

	for (i = 0; i < batch_size; i++)

		__release_stripe(conf, batch[i]);

	return batch_size;

}



/*

 * This is our raid5 kernel thread.
@@ -4584,7 +4608,6 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio) 
 */

static void raid5d(struct mddev *mddev)

{

	struct stripe_head *sh;

	struct r5conf *conf = mddev->private;

	int handled;

	struct blk_plug plug;
@@ -4598,6 +4621,7 @@ static void raid5d(struct mddev *mddev) 
	spin_lock_irq(&conf->device_lock);

	while (1) {

		struct bio *bio;

		int batch_size;



		if (

		    !list_empty(&conf->bitmap_list)) {
@@ -4621,22 +4645,17 @@ static void raid5d(struct mddev *mddev) 
			handled++;

		}



		sh = __get_priority_stripe(conf);



		if (!sh)

		batch_size = handle_active_stripes(conf);

		if (!batch_size)

			break;

		spin_unlock_irq(&conf->device_lock);

		handled += batch_size;



		handled++;

		handle_stripe(sh);

		release_stripe(sh);

		cond_resched();



		if (mddev->flags & ~(1<<MD_CHANGE_PENDING))

		if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {

			spin_unlock_irq(&conf->device_lock);

			md_check_recovery(mddev);



			spin_lock_irq(&conf->device_lock);

		}

	}

	pr_debug("%d stripes handled\n", handled);



	spin_unlock_irq(&conf->device_lock);