Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030297AbVKCPKX (ORCPT ); Thu, 3 Nov 2005 10:10:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030300AbVKCPKX (ORCPT ); Thu, 3 Nov 2005 10:10:23 -0500 Received: from taurus.voltaire.com ([193.47.165.240]:48199 "EHLO taurus.voltaire.com") by vger.kernel.org with ESMTP id S1030266AbVKCPKV (ORCPT ); Thu, 3 Nov 2005 10:10:21 -0500 Date: Thu, 3 Nov 2005 17:09:39 +0200 From: Gleb Natapov To: Hugh Dickins Cc: "Michael S. Tsirkin" , Benjamin Herrenschmidt , Petr Vandrovec , Nick Piggin , Badari Pulavarty , Linux Kernel Mailing List Subject: Re: Nick's core remove PageReserved broke vmware... Message-ID: <20051103150939.GF22185@minantech.com> References: <20051103143713.GB31134@mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-OriginalArrivalTime: 03 Nov 2005 15:10:19.0940 (UTC) FILETIME=[B48F6E40:01C5E088] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1098 Lines: 22 On Thu, Nov 03, 2005 at 02:59:44PM +0000, Hugh Dickins wrote: > > By the way, as a separate issue, we still have a problem with DMA to pages > > which are *needed* by the child process. What do you think about VM_COPY > > (to do the old unix thing of actually copying the page instead of > > setting the COW flag) and a matching madvise call to set/clear it? > > I don't much want to add another path into copy_pte_range, actually > copying pages. If the process really wants DMA into such areas, > then it should contain the code for the child to COW them itself? > I think MPI is the main consumer of Infiniband currently. Unfortunately it's only a library and can't control what users do before or after fork in their applications. It is good to have possibility to copy partially registered pages, there shouldn't be many after all. -- Gleb. - 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/