From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45976) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UQK9W-0003so-2C for qemu-devel@nongnu.org; Thu, 11 Apr 2013 12:15:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UQK9U-0005bT-EZ for qemu-devel@nongnu.org; Thu, 11 Apr 2013 12:15:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46870) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UQK9U-0005b5-3n for qemu-devel@nongnu.org; Thu, 11 Apr 2013 12:15:08 -0400 Message-ID: <5166E0FD.6080808@redhat.com> Date: Thu, 11 Apr 2013 18:12:45 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1365632901-15470-1-git-send-email-mrhines@linux.vnet.ibm.com> <1365632901-15470-11-git-send-email-mrhines@linux.vnet.ibm.com> <20130411073843.GB19601@redhat.com> <51667FEE.903@redhat.com> <5166B9A9.9070904@linux.vnet.ibm.com> <5166C59A.4010904@redhat.com> <5166CF56.2060105@linux.vnet.ibm.com> <5166D1DA.3050804@redhat.com> <5166D826.207@linux.vnet.ibm.com> <5166DAA0.1010507@redhat.com> <5166DEAB.5070309@linux.vnet.ibm.com> In-Reply-To: <5166DEAB.5070309@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH RDMA support v1: 10/13] introduce new command migrate_check_for_zero List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael R. Hines" Cc: aliguori@us.ibm.com, "Michael S. Tsirkin" , qemu-devel@nongnu.org, owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com, gokul@us.ibm.com Il 11/04/2013 18:02, Michael R. Hines ha scritto: > Alright, so here's a slightly different management decision > which tries to accomplish all the requests, > tell me if you like it: > > 1. QEMU starts up > 2. *if and only if* chunk registration is disabled > and *if and only* RDMA is enabled > then, is_dup_page() is skipped > Otherwise, > everything is same as before, no change in code path > and no zero page capability needs to be exposed to management > > In this case there would be *no* capability for zero pages, > but we would still be able to detect the motivation of the > user indirectly through the chunk registration capability > by implying that since the capability was disabled then the > user is trying to optimize metrics for total migration time. > > On the other hand, if the chunk registration capability is > enabled, then there is no change in the code path we because > zero page checking is mandatory to take of chunk registration > in the first place. > > How does that sound? No zero page capability, but allow for > disabling only if chunk registration is disabled? It makes sense, but I prefer to keep the code simple for this first iteration. Let's move zero page detection off the table for now. Paolo