From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:40427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S62lD-0001ql-13 for qemu-devel@nongnu.org; Fri, 09 Mar 2012 11:33:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S62l8-0001Vt-9o for qemu-devel@nongnu.org; Fri, 09 Mar 2012 11:33:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4777) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S62l8-0001Vn-1j for qemu-devel@nongnu.org; Fri, 09 Mar 2012 11:33:38 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q29GXaKW019532 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 9 Mar 2012 11:33:36 -0500 Message-ID: <4F5A31B2.3050701@redhat.com> Date: Fri, 09 Mar 2012 17:37:06 +0100 From: Kevin Wolf MIME-Version: 1.0 References: <1331226917-6658-1-git-send-email-pbonzini@redhat.com> <1331226917-6658-7-git-send-email-pbonzini@redhat.com> In-Reply-To: <1331226917-6658-7-git-send-email-pbonzini@redhat.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org Am 08.03.2012 18:15, schrieb Paolo Bonzini: > Remove the bdrv_co_write_zeroes callback. Instead use the discard > information from bdrv_get_info to choose between bdrv_co_discard > and a normal write. > > Signed-off-by: Paolo Bonzini I'm not sure if this a good idea. The goal of discard is to remove data from the image (or not add it if it isn't there yet) and ideally deallocate the used clusters. The goal of write_zeroes is to mark space as zero and explicitly allocate it for this purpose. >>From a guest point of view these are pretty similar, but from a host perspective I'd say there's a difference. Kevin