From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1Mitb3-0008Gx-U4
	for qemu-devel@nongnu.org; Wed, 02 Sep 2009 13:26:13 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1Mitaz-0008GT-GP
	for qemu-devel@nongnu.org; Wed, 02 Sep 2009 13:26:13 -0400
Received: from [199.232.76.173] (port=36563 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Mitaz-0008GQ-8q
	for qemu-devel@nongnu.org; Wed, 02 Sep 2009 13:26:09 -0400
Received: from verein.lst.de ([213.95.11.210]:37212)
	by monty-python.gnu.org with esmtps
	(TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA1:24) (Exim 4.60)
	(envelope-from <hch@lst.de>) id 1Mitay-0002ee-It
	for qemu-devel@nongnu.org; Wed, 02 Sep 2009 13:26:09 -0400
Date: Wed, 2 Sep 2009 19:26:06 +0200
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH 0/3] block: Handle multiple write requests at
	once
Message-ID: <20090902172606.GA28156@lst.de>
References: <1251813112-17408-1-git-send-email-kwolf@redhat.com>
	<20090901155228.GA21781@lst.de> <4A9E1E4F.4080901@redhat.com>
	<20090902154347.GA23891@lst.de> <4A9E9457.9090904@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4A9E9457.9090904@redhat.com>
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, qemu-devel@nongnu.org

On Wed, Sep 02, 2009 at 05:50:47PM +0200, Kevin Wolf wrote:
> It's a RHEL 5.3 installation, and the kernel doesn't seem to even
> provide this file. However, I think I read that this is an issue of
> relatively new kernels, so probably not?

Indeed.

> What could matter, though, is that the installer uses LVM for the
> standard layout which I'm using. Does this make a difference in that
> respect?

It should not matter.  Then again it should not issue these I/O patterns
at all, but it does.  Something is clearly wrong in those I/O patterns,
but given that the exist out there in the field it seems like we'll have
to deal with it.  I'll look over the patch a bit more carefully to see
if there is any obviously better way to handle it.