From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
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: superflous newlines removed.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jens Axboe <jaxboe@xxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---
mm/swapfile.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- swap2/mm/swapfile.c 2010-09-05 22:45:54.000000000 -0700
+++ swap3/mm/swapfile.c 2010-09-05 22:47:21.000000000 -0700
@@ -139,8 +139,7 @@ static int discard_swap(struct swap_info
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
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
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;
}
--
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