From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45463) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UI0Fv-0008BB-6y for qemu-devel@nongnu.org; Tue, 19 Mar 2013 13:23:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UI0Fr-0000ZR-Tg for qemu-devel@nongnu.org; Tue, 19 Mar 2013 13:23:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51021) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UI0Fr-0000Yz-Mk for qemu-devel@nongnu.org; Tue, 19 Mar 2013 13:23:19 -0400 Date: Tue, 19 Mar 2013 19:23:33 +0200 From: "Michael S. Tsirkin" Message-ID: <20130319172333.GA15579@redhat.com> References: <5147780C.1080800@linux.vnet.ibm.com> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51489D05.2000400@redhat.com> 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: Paolo Bonzini Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, "Michael R. Hines" , owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com, gokul@us.ibm.com On Tue, Mar 19, 2013 at 06:14:45PM +0100, Paolo Bonzini wrote: > Il 19/03/2013 18:09, Michael R. Hines ha scritto: > > Allowing QEMU to swap due to a cgroup limit during migration is a viable > > overcommit option? > > > > I'm trying to keep an open mind, but that would kill the migration > > time..... Maybe not if you have a fast SSD, or are using swap in RAM or compressed swap or ... > Would it swap? Doesn't the kernel back all zero pages with a single > copy-on-write page? If that still accounts towards cgroup limits, it > would be a bug. > > Old kernels do not have a shared zero hugepage, and that includes some > distro kernels. Perhaps that's the problem. > > Paolo AFAIK for zero pages, yes. I'm not sure what the problem is either. -- MST