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Commit c78afc62 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcache/md: Use raid stripe size 



Now that we've got code for raid5/6 stripe awareness, bcache just needs
to know about the stripes and when writing partial stripes is expensive
- we probably don't want to enable this optimization for raid1 or 10,
even though they have stripes. So add a flag to queue_limits.

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
parent 5f5837d2

block/blk-settings.c

+4 −0
Original line number Diff line number Diff line
@@ -592,6 +592,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, 
		ret = -1;

	}



	t->raid_partial_stripes_expensive =

		max(t->raid_partial_stripes_expensive,

		    b->raid_partial_stripes_expensive);



	/* Find lowest common alignment_offset */

	t->alignment_offset = lcm(t->alignment_offset, alignment)

		& (max(t->physical_block_size, t->io_min) - 1);

drivers/md/bcache/super.c

+6 −0
Original line number Diff line number Diff line
@@ -1134,6 +1134,12 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size) 
		hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);

	}



	dc->disk.stripe_size = q->limits.io_opt >> 9;



	if (dc->disk.stripe_size)

		dc->partial_stripes_expensive =

			q->limits.raid_partial_stripes_expensive;



	ret = bcache_device_init(&dc->disk, block_size,

			 dc->bdev->bd_part->nr_sects - dc->sb.data_offset);

	if (ret)

drivers/md/raid5.c

+1 −0
Original line number Diff line number Diff line
@@ -6101,6 +6101,7 @@ static int run(struct mddev *mddev) 
		blk_queue_io_min(mddev->queue, chunk_size);

		blk_queue_io_opt(mddev->queue, chunk_size *

				 (conf->raid_disks - conf->max_degraded));

		mddev->queue->limits.raid_partial_stripes_expensive = 1;

		/*

		 * We can only discard a whole stripe. It doesn't make sense to

		 * discard data disk but write parity disk

include/linux/blkdev.h

+1 −0
Original line number Diff line number Diff line
@@ -291,6 +291,7 @@ struct queue_limits { 
	unsigned char		discard_misaligned;

	unsigned char		cluster;

	unsigned char		discard_zeroes_data;

	unsigned char		raid_partial_stripes_expensive;

};



struct request_queue {