From 8f2ae0faa3a119158c4dcfe89926d6fad5f5332c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 9 Sep 2010 16:38:10 -0700 Subject: [PATCH] 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: Christoph Hellwig Tested-by: Nigel Cunningham Signed-off-by: Tejun Heo Signed-off-by: Hugh Dickins Cc: Jens Axboe Cc: James Bottomley Cc: "Martin K. Petersen" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swapfile.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index ed5151079f59..1894dead0b58 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -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; } -- 2.30.2