From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>, Tejun Heo <tj@kernel.org>,
Jens Axboe <jaxboe@fusionio.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Nigel Cunningham <nigel@tuxonice.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 3/4] swap: do not send discards as barriers
Date: Mon, 6 Sep 2010 01:17:02 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.00.1009060112470.13600@sister.anvils> (raw)
In-Reply-To: <alpine.LSU.2.00.1009060104410.13600@sister.anvils>
From: Christoph Hellwig <hch@infradead.org>
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@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
---
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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next prev parent reply other threads:[~2010-09-06 8:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 8:10 [PATCH 1/4] swap: revert special hibernation allocation Hugh Dickins
2010-09-06 8:12 ` [PATCH 2/4] swap: prevent reuse during hibernation Hugh Dickins
2010-09-06 8:15 ` KAMEZAWA Hiroyuki
2010-09-06 18:34 ` Rafael J. Wysocki
2010-09-07 1:03 ` KOSAKI Motohiro
2010-09-07 20:20 ` Andrew Morton
2010-09-07 21:38 ` Hugh Dickins
2010-09-09 5:44 ` Nigel Cunningham
2010-09-06 8:13 ` [PATCH 1/4] swap: revert special hibernation allocation KAMEZAWA Hiroyuki
2010-09-06 8:17 ` Hugh Dickins [this message]
2010-09-06 8:21 ` [PATCH 4/4] swap: discard while swapping only if SWAP_FLAG_DISCARD Hugh Dickins
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