From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 10/27] xfs: improve sync behaviour in the fact of aggressive dirtying
Date: Thu, 30 Jun 2011 12:52:11 +1000 [thread overview]
Message-ID: <20110630025211.GD561@dastard> (raw)
In-Reply-To: <20110629140338.467151398@bombadil.infradead.org>
On Wed, Jun 29, 2011 at 10:01:19AM -0400, Christoph Hellwig wrote:
> The following script from Wu Fengguang shows very bad behaviour in XFS
> when aggressively dirtying data during a sync on XFS, with sync times
> up to almost 10 times as long as ext4.
>
> A large part of the issue is that XFS writes data out itself two times
> in the ->sync_fs method, overriding the lifelock protection in the core
> writeback code, and another issue is the lock-less xfs_ioend_wait call,
> which doesn't prevent new ioend from beeing queue up while waiting for
> the count to reach zero.
>
> This patch removes the XFS-internal sync calls and relies on the VFS
> to do it's work just like all other filesystems do. Note that the
> i_iocount wait which is rather suboptimal is simply removed here.
> We already do it in ->write_inode, which keeps the current supoptimal
> behaviour. We'll eventually need to remove that as well, but that's
> material for a separate commit.
>
> ------------------------------ snip ------------------------------
> #!/bin/sh
>
> umount /dev/sda7
> mkfs.xfs -f /dev/sda7
> # mkfs.ext4 /dev/sda7
> # mkfs.btrfs /dev/sda7
> mount /dev/sda7 /fs
>
> echo $((50<<20)) > /proc/sys/vm/dirty_bytes
>
> pid=
> for i in `seq 10`
> do
> dd if=/dev/zero of=/fs/zero-$i bs=1M count=1000 &
> pid="$pid $!"
> done
>
> sleep 1
>
> tic=$(date +'%s')
> sync
> tac=$(date +'%s')
>
> echo
> echo sync time: $((tac-tic))
> egrep '(Dirty|Writeback|NFS_Unstable)' /proc/meminfo
>
> pidof dd > /dev/null && { kill -9 $pid; echo sync NOT livelocked; }
> ------------------------------ snip ------------------------------
>
> Reported-by: Wu Fengguang <fengguang.wu@intel.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2011-06-30 2:52 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-29 14:01 [PATCH 00/27] patch queue for Linux 3.1 Christoph Hellwig
2011-06-29 14:01 ` [PATCH 01/27] xfs: PF_FSTRANS should never be set in ->writepage Christoph Hellwig
2011-06-30 1:34 ` Dave Chinner
2011-06-29 14:01 ` [PATCH 02/27] xfs: remove the unused ilock_nowait codepath in writepage Christoph Hellwig
2011-06-30 0:15 ` Dave Chinner
2011-06-30 1:26 ` Dave Chinner
2011-06-30 6:55 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 03/27] xfs: use write_cache_pages for writeback clustering Christoph Hellwig
2011-06-30 2:00 ` Dave Chinner
2011-06-30 2:48 ` Dave Chinner
2011-06-30 6:57 ` Christoph Hellwig
2011-07-01 2:22 ` Dave Chinner
2011-07-01 4:18 ` Dave Chinner
2011-07-01 8:59 ` Christoph Hellwig
2011-07-01 9:20 ` Dave Chinner
2011-07-01 9:33 ` Christoph Hellwig
2011-07-01 14:59 ` Mel Gorman
2011-07-01 15:15 ` Christoph Hellwig
2011-07-02 2:42 ` Dave Chinner
2011-07-05 14:10 ` Mel Gorman
2011-07-05 15:55 ` Dave Chinner
2011-07-11 10:26 ` Christoph Hellwig
2011-07-01 15:41 ` Wu Fengguang
2011-07-04 3:25 ` Dave Chinner
2011-07-05 14:34 ` Mel Gorman
2011-07-06 1:23 ` Dave Chinner
2011-07-11 11:10 ` Christoph Hellwig
2011-07-06 4:53 ` Wu Fengguang
2011-07-06 6:47 ` Minchan Kim
2011-07-06 7:17 ` Dave Chinner
2011-07-06 15:12 ` Johannes Weiner
2011-07-08 9:54 ` Dave Chinner
2011-07-11 17:20 ` Johannes Weiner
2011-07-11 17:24 ` Christoph Hellwig
2011-07-11 19:09 ` Rik van Riel
2011-07-01 8:51 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 04/27] xfs: cleanup xfs_add_to_ioend Christoph Hellwig
2011-06-29 22:13 ` Alex Elder
2011-06-30 2:00 ` Dave Chinner
2011-06-29 14:01 ` [PATCH 05/27] xfs: work around bogus gcc warning in xfs_allocbt_init_cursor Christoph Hellwig
2011-06-29 22:13 ` Alex Elder
2011-06-29 14:01 ` [PATCH 06/27] xfs: split xfs_setattr Christoph Hellwig
2011-06-29 22:13 ` Alex Elder
2011-06-30 7:03 ` Christoph Hellwig
2011-06-30 12:28 ` Alex Elder
2011-06-30 2:11 ` Dave Chinner
2011-06-29 14:01 ` [PATCH 08/27] xfs: kill xfs_itruncate_start Christoph Hellwig
2011-06-29 22:13 ` Alex Elder
2011-06-29 14:01 ` [PATCH 09/27] xfs: split xfs_itruncate_finish Christoph Hellwig
2011-06-30 2:44 ` Dave Chinner
2011-06-30 7:18 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 10/27] xfs: improve sync behaviour in the fact of aggressive dirtying Christoph Hellwig
2011-06-30 2:52 ` Dave Chinner [this message]
2011-06-29 14:01 ` [PATCH 11/27] xfs: fix filesystsem freeze race in xfs_trans_alloc Christoph Hellwig
2011-06-30 2:59 ` Dave Chinner
2011-06-29 14:01 ` [PATCH 12/27] xfs: remove i_transp Christoph Hellwig
2011-06-30 3:00 ` Dave Chinner
2011-06-29 14:01 ` [PATCH 13/27] xfs: factor out xfs_dir2_leaf_find_entry Christoph Hellwig
2011-06-30 6:11 ` Dave Chinner
2011-06-30 7:34 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 14/27] xfs: cleanup shortform directory inode number handling Christoph Hellwig
2011-06-30 6:35 ` Dave Chinner
2011-06-30 7:39 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 15/27] xfs: kill struct xfs_dir2_sf Christoph Hellwig
2011-06-30 7:04 ` Dave Chinner
2011-06-30 7:09 ` Christoph Hellwig
2011-06-29 14:01 ` [PATCH 16/27] xfs: cleanup the defintion of struct xfs_dir2_sf_entry Christoph Hellwig
2011-06-29 14:01 ` [PATCH 17/27] xfs: avoid usage of struct xfs_dir2_block Christoph Hellwig
2011-06-29 14:01 ` [PATCH 18/27] xfs: kill " Christoph Hellwig
2011-06-29 14:01 ` [PATCH 19/27] xfs: avoid usage of struct xfs_dir2_data Christoph Hellwig
2011-06-29 14:01 ` [PATCH 20/27] xfs: kill " Christoph Hellwig
2011-06-29 14:01 ` [PATCH 21/27] xfs: cleanup the defintion of struct xfs_dir2_data_entry Christoph Hellwig
2011-06-29 14:01 ` [PATCH 22/27] xfs: cleanup struct xfs_dir2_leaf Christoph Hellwig
2011-06-29 14:01 ` [PATCH 23/27] xfs: remove the unused xfs_bufhash structure Christoph Hellwig
2011-06-29 14:01 ` [PATCH 24/27] xfs: clean up buffer locking helpers Christoph Hellwig
2011-06-29 14:01 ` [PATCH 25/27] xfs: return the buffer locked from xfs_buf_get_uncached Christoph Hellwig
2011-06-29 14:01 ` [PATCH 26/27] xfs: cleanup I/O-related buffer flags Christoph Hellwig
2011-06-29 14:01 ` [PATCH 27/27] xfs: avoid a few disk cache flushes Christoph Hellwig
2011-06-30 6:36 ` [PATCH 00/27] patch queue for Linux 3.1 Dave Chinner
2011-06-30 6:50 ` Christoph Hellwig
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