From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=54472 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P5hbY-0001Jq-Rh for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:21:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P5hbX-0007Yt-2c for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:21:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9275) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P5hbW-0007YB-SP for qemu-devel@nongnu.org; Tue, 12 Oct 2010 12:21:31 -0400 Message-ID: <4CB48AFF.6020206@redhat.com> Date: Tue, 12 Oct 2010 18:21:19 +0200 From: Avi Kivity MIME-Version: 1.0 References: <1286552914-27014-1-git-send-email-stefanha@linux.vnet.ibm.com> <1286552914-27014-7-git-send-email-stefanha@linux.vnet.ibm.com> <4CB479D2.7030901@redhat.com> <4CB47D38.3060602@linux.vnet.ibm.com> <4CB48144.9030607@redhat.com> <20101012155953.GA13872@stefan-thinkpad.transitives.com> <4CB489D1.3050204@linux.vnet.ibm.com> In-Reply-To: <4CB489D1.3050204@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH v2 6/7] qed: Read/write support List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Kevin Wolf , Christoph Hellwig , Stefan Hajnoczi , qemu-devel@nongnu.org On 10/12/2010 06:16 PM, Anthony Liguori wrote: > > It's fairly simple to add a sync to this path. It's probably worth > checking the prefill/postfill for zeros and avoiding the write/sync if > that's the case. That should optimize the common cases of allocating > new space within a file. > > My intuition is that we can avoid the sync entirely but we'll need to > think about it further. > I don't think so. This isn't a guest initiated write so we can't shift responsibility to the guest. -- error compiling committee.c: too many arguments to function