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From: Eric Sandeen <sandeen@sandeen.net>
To: Christoph Hellwig <hch@infradead.org>, Brian Foster <bfoster@redhat.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH] xfs: defer online discard submission to a workqueue
Date: Mon, 5 Nov 2018 16:20:24 -0600	[thread overview]
Message-ID: <41f009c2-8f17-ca67-6981-72160bdc94c7@sandeen.net> (raw)
In-Reply-To: <20181105215139.GA3160@infradead.org>

On 11/5/18 3:51 PM, Christoph Hellwig wrote:
> On Mon, Nov 05, 2018 at 01:10:21PM -0500, Brian Foster wrote:
>> When online discard is enabled, discards of busy extents are
>> submitted asynchronously as a bio chain. bio completion and
>> resulting busy extent cleanup is deferred to a workqueue. Async
>> discard submission is intended to avoid blocking log forces on a
>> full discard sequence which can take a noticeable amount of time in
>> some cases.
>>
>> We've had reports of this still producing log force stalls with XFS
>> on VDO,
> 
> Please fix this in VDO instead.  We should not work around out of
> tree code making stupid decisions.

Is there some downside to Brian's proposal, in principle?
It seems like it would be an improvement for device that might cause
a discard bottleneck like this.

Thanks,
-Eric

  reply	other threads:[~2018-11-06  7:42 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-05 18:10 [PATCH] xfs: defer online discard submission to a workqueue Brian Foster
2018-11-05 21:51 ` Christoph Hellwig
2018-11-05 22:20   ` Eric Sandeen [this message]
2018-11-09 15:04     ` Christoph Hellwig
2018-11-06 14:23   ` Brian Foster
2018-11-06 21:18     ` Dave Chinner
2018-11-07 13:42       ` Brian Foster
2018-11-08  0:38         ` Dave Chinner
2018-11-08 13:50           ` Brian Foster
2018-11-09  0:20             ` Dave Chinner
2018-11-09 15:23               ` Brian Foster
2018-11-09 15:06     ` Christoph Hellwig
2018-11-09 15:46       ` Brian Foster

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