From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org, Chris Mason <chris.mason@oracle.com>
Subject: Re: [PATCH] block: fix DISCARD_BARRIER requests
Date: Thu, 17 Jun 2010 10:10:18 +0200 [thread overview]
Message-ID: <4C19D86A.5030709@kernel.dk> (raw)
In-Reply-To: <20100617075432.GA22407@lst.de>
On 2010-06-17 09:54, Christoph Hellwig wrote:
> Filesystems assume that DISCARD_BARRIER are full barriers, so that they
> don't have to track in-progress discard operation when submitting new I/O.
> But currently we only treat them as elevator barriers, which don't
> actually do the nessecary queue drains.
>
> Also remove the unlikely around both the DISCARD and BARRIER requests -
> the happen far too often for a static mispredict.
Thanks, applied. There was a recent problem report on btrfs using
discard, could possibly explain it if Chris assumed it was a full
barrier.
--
Jens Axboe
next prev parent reply other threads:[~2010-06-17 8:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-17 7:54 [PATCH] block: fix DISCARD_BARRIER requests Christoph Hellwig
2010-06-17 8:10 ` Jens Axboe [this message]
2010-06-17 11:49 ` Matthew Wilcox
2010-06-17 12:06 ` Jens Axboe
2010-06-17 16:54 ` Christoph Hellwig
2010-06-17 19:22 ` Chris Mason
2010-06-18 13:29 ` Kyungmin Park
2010-06-19 2:22 ` Kyungmin Park
2010-06-18 15:29 ` Jamie Lokier
2010-06-18 20:30 ` Chris Mason
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