From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dZeJm-00074D-3F for qemu-devel@nongnu.org; Mon, 24 Jul 2017 10:26:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dZeJi-00018f-Pe for qemu-devel@nongnu.org; Mon, 24 Jul 2017 10:26:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36538) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dZeJi-00017z-In for qemu-devel@nongnu.org; Mon, 24 Jul 2017 10:26:38 -0400 References: <20170719100802.14094-1-berrange@redhat.com> <20170719100802.14094-2-berrange@redhat.com> <20170724141108.GA11443@redhat.com> From: Paolo Bonzini Message-ID: Date: Mon, 24 Jul 2017 16:26:24 +0200 MIME-Version: 1.0 In-Reply-To: <20170724141108.GA11443@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v5 1/2 (for 2.10)] docs: document support lifetime for features List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Thomas Huth , qemu-devel@nongnu.org, Peter Maydell , Stefan Hajnoczi , Markus Armbruster , Eduardo Habkost On 24/07/2017 16:11, Daniel P. Berrange wrote: >>> + >>> +The supported lifetime for versioned machine types is 12 releases, >>> +which is equivalent to 4 years worth of previous QEMU releases. >> I think there's still no consensus on this. >=20 > Indeed, which is exactly why I sent this patch - we need to come up > with a sensible policy here, so we can stop repeating the same debate > over & over & over each time some proposes a patch to kill off some > random old machine type. >=20 > The 12 release / 4 year figure was a fairly arbitrary starting > point to which I'd be hoping to see critical reviewer feedback > on (with possible counterproposals) so we can try to get something > documented, to put an end to the repeated debates in this area > each time someone proposes a patch. I agree. At the moment, the status is "machine types never die". We can change it, but I think that we should also make a decision on whether removing machine types implies removing properties that only exist for backwards-compatibility reasons. 4 year seems like a long time, but it can actually be pretty taxing for RHEL. I'm pretty sure that around RHEL 8.4 (some time between 2020-2022) we'll need a 1.5-ish machine type (2016). Paolo >> The first two paragraphs >> should be added to the documentation for -machine in qemu-options.hx, >> since "-machine [type=3D]foo" is currently not documented at all. > I'll happily send a patch for the docs for qemu-options.hx.