From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1csvSr-0006gi-Oh for qemu-devel@nongnu.org; Tue, 28 Mar 2017 14:03:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1csvSo-0003Uf-Fb for qemu-devel@nongnu.org; Tue, 28 Mar 2017 14:03:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50808) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1csvSo-0003UX-Ag for qemu-devel@nongnu.org; Tue, 28 Mar 2017 14:03:26 -0400 Date: Tue, 28 Mar 2017 19:03:21 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20170328180321.GH5740@work-vm> References: <20170323205025.12113-1-quintela@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170323205025.12113-1-quintela@redhat.com> Subject: Re: [Qemu-devel] [RFC 0/2] Disable hotplug during migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela , lizhijian@cn.fujitsu.com, wency@cn.fujitsu.com Cc: qemu-devel@nongnu.org * Juan Quintela (quintela@redhat.com) wrote: > Hi > > This series disable hotplug/unplug during migration. Thank to Markus > for explaining where I had to put the checks. Why? Because during > migration we will fail if there are changes. For instance, in > postcopy, if we add a memory region, we would failing. Same for other > devices if they are not setup exactly the same on destination. > > Iidea would be to disable it, andthen enable for the thing that we know that work. > > This series are on top of my previous RAMState v2 serie. > > Commets, please? So I think this is probably a good idea, but we should ask Li Zhijian who added migration_bitmap_extend if the reason for adding it was because they needed the hot add to work. cc'd. IMHO we really need a 'configuration change mutex' that you can take to stop any changes in the VM hardware, and that would probably reduce a lot of the places that hold the BQL for just stopping changes. Dave > > Thanks, Juan. > > > Juan Quintela (2): > migration: Disable hotplug/unplug during migration > ram: remove migration_bitmap_extend() > > exec.c | 1 - > hw/core/qdev.c | 5 +++++ > include/exec/ram_addr.h | 2 -- > migration/ram.c | 34 ---------------------------------- > qdev-monitor.c | 7 ++++++- > 5 files changed, 11 insertions(+), 38 deletions(-) > > -- > 2.9.3 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK