From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([140.186.70.92]:55356)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <kwolf@redhat.com>) id 1QMbiG-0007Ae-6P
	for qemu-devel@nongnu.org; Wed, 18 May 2011 04:02:36 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <kwolf@redhat.com>) id 1QMbiF-0001N1-4t
	for qemu-devel@nongnu.org; Wed, 18 May 2011 04:02:36 -0400
Received: from mx1.redhat.com ([209.132.183.28]:16242)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <kwolf@redhat.com>) id 1QMbiE-0001Mv-Tn
	for qemu-devel@nongnu.org; Wed, 18 May 2011 04:02:35 -0400
Message-ID: <4DD37DBC.8090500@redhat.com>
Date: Wed, 18 May 2011 10:05:16 +0200
From: Kevin Wolf <kwolf@redhat.com>
MIME-Version: 1.0
References: <BANLkTinHhx5jTgcH-cytci=fNdk2V7zssg@mail.gmail.com>	<BANLkTim6osGVGU8oqpx0ZcOVU17c7LS5AA@mail.gmail.com>	<BANLkTikodwB2aNsPL42DCk=dq43pg+kKQw@mail.gmail.com>
	<BANLkTinbceD4PVaHabCzYxyT7EtFnTNKtg@mail.gmail.com>
In-Reply-To: <BANLkTinbceD4PVaHabCzYxyT7EtFnTNKtg@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] [qemu-img] CPU consuming optimization
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: stanislav.ievlev@gmail.com, Dmitry Konishchev <konishchev@gmail.com>, qemu-devel@nongnu.org

Am 18.05.2011 09:57, schrieb Stefan Hajnoczi:
> On Wed, May 18, 2011 at 7:55 AM, Dmitry Konishchev <konishchev@gmail.com> wrote:
>> So, if you are agreed with the said above, you can accept this patch
>> and then I'll write an enchancement for it with bdrv_is_allocated()
>> because it is going to include this patch.
> 
> Yes, optimizing is_not_zero() is good.  The only additional thing I
> suggest is adding a comment before the function to document the length
> constraint.
> 
> Kevin Wolf is CCed, he's the QEMU block layer maintainer and may have
> additional thoughts before accepting this patch.

For this one not really. Except for the coding style it looks good to me.

A future bdrv_is_allocated() patch must make sure that the conversion
falls back to a simple is_not_zero() when a backing file is used.

Kevin