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Commit 8f2ae0fa authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

swap: do not send discards as barriers 



The swap code already uses synchronous discards, no need to add I/O
barriers.

This fixes the worst of the terrible slowdown in swap allocation for
hibernation, reported on 2.6.35 by Nigel Cunningham; but does not entirely
eliminate that regression.

[tj@kernel.org: superflous newlines removed]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarNigel Cunningham <nigel@tuxonice.net>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b73d7fce

mm/swapfile.c

+3 −6
Original line number Diff line number Diff line
@@ -139,8 +139,7 @@ static int discard_swap(struct swap_info_struct *si) 
	nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9);

	if (nr_blocks) {

		err = blkdev_issue_discard(si->bdev, start_block,

				nr_blocks, GFP_KERNEL,

				BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);

				nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);

		if (err)

			return err;

		cond_resched();
@@ -151,8 +150,7 @@ static int discard_swap(struct swap_info_struct *si) 
		nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9);



		err = blkdev_issue_discard(si->bdev, start_block,

				nr_blocks, GFP_KERNEL,

				BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);

				nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);

		if (err)

			break;
@@ -191,8 +189,7 @@ static void discard_swap_cluster(struct swap_info_struct *si, 
			start_block <<= PAGE_SHIFT - 9;

			nr_blocks <<= PAGE_SHIFT - 9;

			if (blkdev_issue_discard(si->bdev, start_block,

				    nr_blocks, GFP_NOIO, BLKDEV_IFL_WAIT |

							BLKDEV_IFL_BARRIER))

				    nr_blocks, GFP_NOIO, BLKDEV_IFL_WAIT))

				break;

		}