From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <47B46AFB.9070009@opengridcomputing.com> Date: Thu, 14 Feb 2008 10:23:23 -0600 From: Steve Wise MIME-Version: 1.0 Subject: Re: [ofa-general] Re: Demand paging for memory regions References: <8A71B368A89016469F72CD08050AD334026D5C23@maui.asicdesigners.com> <47B45994.7010805@opengridcomputing.com> <20080214155333.GA1029@sgi.com> In-Reply-To: <20080214155333.GA1029@sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Robin Holt Cc: Felix Marti , Roland Dreier , Christoph Lameter , Rik van Riel , steiner@sgi.com, Andrea Arcangeli , a.p.zijlstra@chello.nl, izike@qumranet.com, linux-kernel@vger.kernel.org, avi@qumranet.com, linux-mm@kvack.org, daniel.blueman@quadrics.com, general@lists.openfabrics.org, Andrew Morton , kvm-devel@lists.sourceforge.net List-ID: Robin Holt wrote: > On Thu, Feb 14, 2008 at 09:09:08AM -0600, Steve Wise wrote: >> Note that for T3, this involves suspending _all_ rdma connections that are >> in the same PD as the MR being remapped. This is because the driver >> doesn't know who the application advertised the rkey/stag to. So without > > Is there a reason the driver can not track these. > Because advertising of a MR (ie telling the peer about your rkey/stag, offset and length) is application-specific and can be done out of band, or in band as simple SEND/RECV payload. Either way, the driver has no way of tracking this because the protocol used is application-specific. >> Point being, it will stop probably all connections that an application is >> using (assuming the application uses a single PD). > > It seems like the need to not stop all would be a compelling enough reason > to modify the driver to track which processes have received the rkey/stag. > Yes, _if_ the driver could track this. And _if_ the rdma API and paradigm was such that the kernel/driver could keep track, then remote revokations of MR tags could be supported. Stevo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org