From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59515) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhWG-0000bg-4y for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:35:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIhW7-0001hx-Mz for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:35:07 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:36537) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhK5-0001aE-WD for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:22:34 -0400 Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Mar 2013 09:22:23 -0600 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 694FF6E8020 for ; Thu, 21 Mar 2013 11:22:18 -0400 (EDT) Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r2LFMJLg188296 for ; Thu, 21 Mar 2013 11:22:20 -0400 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r2LFOht4011798 for ; Thu, 21 Mar 2013 09:24:43 -0600 Message-ID: <514B2598.5060503@linux.vnet.ibm.com> Date: Thu, 21 Mar 2013 11:22:00 -0400 From: "Michael R. Hines" MIME-Version: 1.0 References: <20130318212646.GB20406@redhat.com> <5147A209.80202@linux.vnet.ibm.com> <20130319081939.GC11259@redhat.com> <51487F68.2060305@linux.vnet.ibm.com> <20130319151606.GA13649@redhat.com> <51488521.4010909@linux.vnet.ibm.com> <20130319153658.GA14317@redhat.com> <51489BC3.3030504@linux.vnet.ibm.com> <51489D05.2000400@redhat.com> <5148A52E.6020208@linux.vnet.ibm.com> <20130321061159.GA28328@redhat.com> In-Reply-To: <20130321061159.GA28328@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH RDMA support v4: 03/10] more verbose documentation of the RDMA transport List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com, gokul@us.ibm.com, Paolo Bonzini Very nice catch. Yes, I didn't think about that. Thanks. On 03/21/2013 02:11 AM, Michael S. Tsirkin wrote: > > I really shouldn't break COW if you don't request LOCAL_WRITE. > I think it's a kernel bug, and apparently has been there in the code since the > first version: get_user_pages parameters swapped. > > I'll send a patch. If it's applied, you should also > change your code from > > + IBV_ACCESS_LOCAL_WRITE | > + IBV_ACCESS_REMOTE_WRITE | > + IBV_ACCESS_REMOTE_READ); > > to > > + IBV_ACCESS_REMOTE_READ); > > on send side. > Then, each time we detect a page has changed we must make sure to > unregister and re-register it. Or if you want to be very > smart, check that the PFN didn't change and reregister > if it did. > > This will make overcommit work. >