From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark McLoughlin <markmc@redhat.com>
Subject: Re: [PATCH] Segments can span multiple clusters
	withtap:qcow
Date: Thu, 03 May 2007 18:47:49 +0100
Message-ID: <1178214469.14747.2.camel@blaa>
References: <C25FDD27.E5EB%keir@xensource.com>
Mime-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <C25FDD27.E5EB%keir@xensource.com>
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Keir Fraser <keir@xensource.com>
Cc: Jake Wires <Jake.Wires@xensource.com>, xen-devel <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

On Thu, 2007-05-03 at 18:40 +0100, Keir Fraser wrote:
> On 3/5/07 02:06, "Jake Wires" <Jake.Wires@xensource.com> wrote:
> 
> > This patch is back to only allocating enough requests for one segment:
> > 
> > +        /* A segment (i.e. a page) can span multiple clusters */
> > +        s->max_aio_reqs = (getpagesize() / s->cluster_size) + 1;
> > 
> > In fact, this code allocates exactly two AIO requests for QCoW images
> > created by qcow-create, which have a default cluster size of 4K.
> 
> What shall we do -- revert the whole patch or fix this line?

	Goodness, words fail me. In all the confusion I created, that fix got
lost again. It should be:

+        s->max_aio_reqs = ((getpagesize() / s->cluster_size) + 1) * MAX_SEGMENTS_PER_REQ * MAX_REQUESTS;

Thanks,
Mark.