From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752687AbbDAK54 (ORCPT ); Wed, 1 Apr 2015 06:57:56 -0400 Received: from e06smtp10.uk.ibm.com ([195.75.94.106]:44571 "EHLO e06smtp10.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750848AbbDAK5z (ORCPT ); Wed, 1 Apr 2015 06:57:55 -0400 Date: Wed, 1 Apr 2015 12:57:48 +0200 From: Cornelia Huck To: "Michael S. Tsirkin" Cc: Rusty Russell , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v2 1/6] virtio_balloon: transitional interface Message-ID: <20150401125748.2ec33b97.cornelia.huck@de.ibm.com> In-Reply-To: <20150401122413-mutt-send-email-mst@redhat.com> References: <1427831230-28044-1-git-send-email-mst@redhat.com> <1427831230-28044-2-git-send-email-mst@redhat.com> <87mw2sy0fo.fsf@rustcorp.com.au> <20150401094236-mutt-send-email-mst@redhat.com> <87h9t06w3h.fsf@rustcorp.com.au> <20150401113300-mutt-send-email-mst@redhat.com> <20150401122244.5a033ff5.cornelia.huck@de.ibm.com> <20150401122413-mutt-send-email-mst@redhat.com> Organization: IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz =?UTF-8?B?R2VzY2jDpGZ0c2bDvGhydW5nOg==?= Dirk Wittkopp Sitz der Gesellschaft: =?UTF-8?B?QsO2Ymxpbmdlbg==?= Registergericht: Amtsgericht Stuttgart, HRB 243294 X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15040110-0041-0000-0000-000003C97B46 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Apr 2015 12:28:30 +0200 "Michael S. Tsirkin" wrote: > On Wed, Apr 01, 2015 at 12:22:44PM +0200, Cornelia Huck wrote: > > On Wed, 1 Apr 2015 11:43:46 +0200 > > "Michael S. Tsirkin" wrote: > > > > > On Wed, Apr 01, 2015 at 07:53:14PM +1030, Rusty Russell wrote: > > > > "Michael S. Tsirkin" writes: > > > > > On Wed, Apr 01, 2015 at 02:17:23PM +1030, Rusty Russell wrote: > > > > >> I would leave the device *exactly* as is, ugly structure packing and > > > > >> all. > > > > > > > > > > But why? It's going to be used for years, might as well make it clean? > > > > > > > > Because the only spec which currently exists says to do that. > > > > > > OK but the only spec which currently exists also says it's a legacy only > > > device, so driver must not set VERSION_1. So surely, we can make minor > > > changes when VERSION_1 is set, like we did for other devices. > > > > But we don't plan to replace the other devices, so it makes sense to do > > some changes for 1.0. > > I'm not sure what the above says. Do you agree with > making minor changes in device behaviour? The other way around. > Also to be clear, I think this is 1.1 material. Btw, I'd really like to see your proposed spec updates. > > > > > > > Let me post the latest patches I'm working on, > > > see what you think then. > > > > > > > We do > > > > need a new virtio memballoon spec, but it'll look nothing like this > > > > anyway. > > > > > > > > Cheers, > > > > Rusty. > > > > > > I think it's going to have significantly different semantics, too, > > > so not much value in making that one work with current > > > drivers, right? > > > > > > > So why not just keep virtio-balloon as-is and just specify endianness > > etc. for 1.0? Keeps the old drivers going without hacks, > > and we can > > start with a fresh driver for the new virtio-balloon. > > Well it doesn't really, we need cpu_to_virtio in a bunch of > places anyway. Of course, but what about keeping changes minimal? > > So I kind of prefer making it clean, even just to avoid setting a bad > example for other devices. > > Let me post the new patch where it's all fixed in a cleaner way, and > everyone can discuss whether it's too much work. >