Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762104AbYBMEry (ORCPT ); Tue, 12 Feb 2008 23:47:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754786AbYBMErq (ORCPT ); Tue, 12 Feb 2008 23:47:46 -0500 Received: from mailbox2.myri.com ([64.172.73.26]:1847 "EHLO myri.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754305AbYBMErp (ORCPT ); Tue, 12 Feb 2008 23:47:45 -0500 Message-ID: <47B2765A.2070901@myri.com> Date: Tue, 12 Feb 2008 23:47:22 -0500 From: Patrick Geoffray Organization: Myricom, Inc User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Jason Gunthorpe CC: Christoph Lameter , Roland Dreier , linux-kernel@vger.kernel.org, linux-mm@kvack.org, general@lists.openfabrics.org Subject: Re: [ofa-general] Re: Demand paging for memory regions References: <20080209075556.63062452@bree.surriel.com> <47B2174E.5000708@opengridcomputing.com> <20080213032533.GC32047@obsidianresearch.com> <47B26A6A.4000209@myri.com> <20080213042600.GA32449@obsidianresearch.com> In-Reply-To: <20080213042600.GA32449@obsidianresearch.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1432 Lines: 34 Jason Gunthorpe wrote: > [mangled CC list trimmed] Thanks, noticed that afterwards. > This wasn't ment as a slight against Quadrics, only to point out that > the specific wire protcols used by IB and iwarp are what cause this > limitation, it would be easy to imagine that Quadrics has some > additional twist that can make this easier.. The wire protocols are similar, nothing fancy. The specificity of Quadrics (and many others) is that they can change the behavior of the NIC in firmware, so they adapt to what the OS offers. They had the VM notifier support in Tru64 back in the days, they just ported the functionality to Linux. > I ment that HPC users are unlikely to want to swap active RDMA pages > if this causes a performance cost on normal operations. None of my Swapping to disk is not a normal operations in HPC, it's going to be slow anyway. The main problem for HPC users is not swapping, it's that they do not know when a registered page is released to the OS through free(), sbrk() or munmap(). Like swapping, they don't expect that it will happen often, but they have to handle it gracefully. Patrick -- Patrick Geoffray Myricom, Inc. http://www.myri.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/