From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57538) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UPf4U-0001iN-J2 for qemu-devel@nongnu.org; Tue, 09 Apr 2013 16:23:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UPf4S-0008Cq-0H for qemu-devel@nongnu.org; Tue, 09 Apr 2013 16:23:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1887) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UPez5-0006Qs-OC for qemu-devel@nongnu.org; Tue, 09 Apr 2013 16:17:39 -0400 Date: Tue, 9 Apr 2013 22:12:18 +0300 From: "Michael S. Tsirkin" Message-ID: <20130409191218.GD8212@redhat.com> References: <20130324155153.GA8597@redhat.com> <515F3160.4020007@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCHv2] rdma: add a new IB_ACCESS_GIFT flag List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Roland Dreier Cc: qemu-devel@nongnu.org, "linux-rdma@vger.kernel.org" , Yishai Hadas , LKML , "Michael R. Hines" , Hal Rosenstock , Jason Gunthorpe , Sean Hefty , Christoph Lameter On Fri, Apr 05, 2013 at 01:43:49PM -0700, Roland Dreier wrote: > On Fri, Apr 5, 2013 at 1:17 PM, Michael R. Hines > wrote: > > I also removed the IBV_*_WRITE flags on the sender-side and activated > > cgroups with the "memory.memsw.limit_in_bytes" activated and the migration > > with RDMA also succeeded without any problems (both with *and* without GIFT > > also worked). > > Not sure I'm interpreting this correctly. Are you saying that things > worked without actually setting the GIFT flag? In which case why are > we adding this flag? > > - R. We are adding the flag to reduce memory when there's lots of COW pages. There's no guarantee there will be COW pages so I expect things to work both with and without breaking COW, just using much more memory when we break COW. -- MST