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 <hch@lst.de>
Tested-by: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hugh 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index ed51510..1894dea 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -139,8 +139,7 @@
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 @@
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 @@
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;
}