From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f172.google.com (mail-pf0-f172.google.com [209.85.192.172]) by kanga.kvack.org (Postfix) with ESMTP id 8E19E6B0005 for ; Thu, 10 Mar 2016 02:44:33 -0500 (EST) Received: by mail-pf0-f172.google.com with SMTP id 129so62525280pfw.1 for ; Wed, 09 Mar 2016 23:44:33 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTP id gy5si4217894pac.83.2016.03.09.23.44.32 for ; Wed, 09 Mar 2016 23:44:32 -0800 (PST) From: "Li, Liang Z" Subject: RE: [RFC qemu 0/4] A PV solution for live migration optimization Date: Thu, 10 Mar 2016 07:44:19 +0000 Message-ID: References: <1457001868-15949-1-git-send-email-liang.z.li@intel.com> <20160308111343.GM15443@grmbl.mre> In-Reply-To: <20160308111343.GM15443@grmbl.mre> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Amit Shah Cc: "quintela@redhat.com" , "qemu-devel@nongnu.org" , "linux-kernel@vger.kernel.org" , "mst@redhat.com" , "akpm@linux-foundation.org" , "pbonzini@redhat.com" , "rth@twiddle.net" , "ehabkost@redhat.com" , "linux-mm@kvack.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "dgilbert@redhat.com" > > This patch set is the QEMU side implementation. > > > > The virtio-balloon is extended so that QEMU can get the free pages > > information from the guest through virtio. > > > > After getting the free pages information (a bitmap), QEMU can use it > > to filter out the guest's free pages in the ram bulk stage. This make > > the live migration process much more efficient. > > > > This RFC version doesn't take the post-copy and RDMA into > > consideration, maybe both of them can benefit from this PV solution by > > with some extra modifications. >=20 > I like the idea, just have to prove (review) and test it a lot to ensure = we don't > end up skipping pages that matter. >=20 > However, there are a couple of points: >=20 > In my opinion, the information that's exchanged between the guest and the > host should be exchanged over a virtio-serial channel rather than virtio- > balloon. First, there's nothing related to the balloon here. > It just happens to be memory info. Second, I would never enable balloon = in > a guest that I want to be performance-sensitive. So even if you add this= as > part of balloon, you'll find no one is using this solution. >=20 > Secondly, I suggest virtio-serial, because it's meant exactly to exchange= free- > flowing information between a host and a guest, and you don't need to > extend any part of the protocol for it (hence no changes necessary to the > spec). You can see how spice, vnc, etc., use virtio-serial to exchange d= ata. >=20 >=20 > Amit Hi Amit, Could provide more information on how to use virtio-serial to exchange dat= a? Thread , Wiki or code are all OK.=20 I have not find some useful information yet. Thanks Liang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org