From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45785) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqIly-0002YD-SN for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:15:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aqIlt-00089f-UD for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:15:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44988) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqIlt-00089V-PI for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:15:45 -0400 Date: Wed, 13 Apr 2016 12:15:38 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20160413111538.GA6367@work-vm> References: <1459138565-6244-1-git-send-email-jitendra.kolhe@hpe.com> <20160329151921-mutt-send-email-mst@redhat.com> <56FE56AC.8050903@hpe.com> <20160410184239-mutt-send-email-mst@redhat.com> <570E257F.3060205@hpe.com> <20160413111032.GA22137@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160413111032.GA22137@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2] migration: skip sending ram pages released by virtio-balloon driver. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Jitendra Kolhe , qemu-devel@nongnu.org, pbonzini@redhat.com, crosthwaite.peter@gmail.com, rth@twiddle.net, eblake@redhat.com, lcapitulino@redhat.com, stefanha@redhat.com, armbru@redhat.com, quintela@redhat.com, den@openvz.org, JBottomley@Odin.com, borntraeger@de.ibm.com, amit.shah@redhat.com, ehabkost@redhat.com, mohan_parthasarathy@hpe.com, simhan@hpe.com * Michael S. Tsirkin (mst@redhat.com) wrote: > On Wed, Apr 13, 2016 at 04:24:55PM +0530, Jitendra Kolhe wrote: > > Can we extend support for post-copy in a different patch set? > > If the optimization does not *help* on some paths, > that's fine. The issue is with adding extra code > special-casing protocols: > > + if (migrate_postcopy_ram()) { > + balloon_bitmap_disable_state = BALLOON_BITMAP_DISABLE_PERMANENT; > + } > > Generally when one sees that patchset breaks XYZ... > the easy solution is "check for XYZ > and disable the optimization". But do this enough times > and the codebase becomes impossible to reason about. > why did migration become slower? oh it enabled > optimization A and that conflicts with optimization B ... Hang on; this is getting all very complicated; I wouldn't start tieing this thing up with postcopy yet. Lets try and keep this simple for starters. Dave > > > > and use > > current patch set to support other remaining protocols? > > Even disregarding postcopy, I think there were > comments that need to be addressed. > > -- > MST -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK