From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 12 Feb 2008 17:01:17 -0800 (PST) From: Christoph Lameter Subject: Re: [ofa-general] Re: Demand paging for memory regions In-Reply-To: <20080212232329.GC31435@obsidianresearch.com> Message-ID: References: <20080209012446.GB7051@v2.random> <20080209015659.GC7051@v2.random> <20080209075556.63062452@bree.surriel.com> <47B2174E.5000708@opengridcomputing.com> <20080212232329.GC31435@obsidianresearch.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Jason Gunthorpe Cc: Roland Dreier , 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, Robin Holt , general@lists.openfabrics.org, Andrew Morton , kvm-devel@lists.sourceforge.net List-ID: On Tue, 12 Feb 2008, Jason Gunthorpe wrote: > Well, certainly today the memfree IB devices store the page tables in > host memory so they are already designed to hang onto packets during > the page lookup over PCIE, adding in faulting makes this time > larger. You really do not need a page table to use it. What needs to be maintained is knowledge on both side about what pages are currently shared across RDMA. If the VM decides to reclaim a page then the notification is used to remove the remote entry. If the remote side then tries to access the page again then the page fault on the remote side will stall until the local page has been brought back. RDMA can proceed after both sides again agree on that page now being sharable. -- 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