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From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 2/5] xfs: use per-filesystem I/O completion workqueues
Date: Wed, 9 Nov 2011 10:11:18 +1100	[thread overview]
Message-ID: <20111108231118.GP5534@dastard> (raw)
In-Reply-To: <20111108085846.291838677@bombadil.infradead.org>

On Tue, Nov 08, 2011 at 03:56:16AM -0500, Christoph Hellwig wrote:
> The new concurrency managed workqueues are cheap enough that we can create
> per-filesystem instead of global workqueues.  This allows us to remove the
> trylock or defer scheme on the ilock, which has the potential of delaying
> size updates, and is not helpful once we start to log the inode size.

So why does the per-mount workqueues allow removal of the trylock?

IOWs, it might be worthwhile pointing to the commit (77d7a0c "xfs:
Non-blocking inode locking in IO completion") to indicate that the
functionality being removed was introduced to avoid IO completion
deadlocks between dependent filesystems (e.g. XFS on loop device on
XFS) and that moving to per-mount completion queues removes that
dependency....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2011-11-08 23:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-08  8:56 [PATCH 0/5] log all file size updates Christoph Hellwig
2011-11-08  8:56 ` [PATCH 1/5] fix: force shutdown handling in xfs_end_io Christoph Hellwig
2011-11-08  8:56 ` [PATCH 2/5] xfs: use per-filesystem I/O completion workqueues Christoph Hellwig
2011-11-08 23:11   ` Dave Chinner [this message]
2011-11-09  7:58     ` Christoph Hellwig
2011-11-10 17:42       ` Ben Myers
2011-11-14 10:34         ` Christoph Hellwig
2011-11-14 18:13           ` Tejun Heo
2011-11-08  8:56 ` [PATCH 3/5] xfs: do not require an ioend for new EOF calculation Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2011-11-15 20:14 [PATCH 0/5] for-3.2 queue Christoph Hellwig
2011-11-15 20:14 ` [PATCH 2/5] xfs: use per-filesystem I/O completion workqueues Christoph Hellwig
2011-11-16 19:01   ` Ben Myers
2011-11-17  7:40     ` Christoph Hellwig
2011-11-16 23:24   ` Dave Chinner
2011-11-17  7:25     ` Christoph Hellwig

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