Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030244AbVKCPAw (ORCPT ); Thu, 3 Nov 2005 10:00:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030246AbVKCPAw (ORCPT ); Thu, 3 Nov 2005 10:00:52 -0500 Received: from gold.veritas.com ([143.127.12.110]:5729 "EHLO gold.veritas.com") by vger.kernel.org with ESMTP id S1030244AbVKCPAv (ORCPT ); Thu, 3 Nov 2005 10:00:51 -0500 Date: Thu, 3 Nov 2005 14:59:44 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: "Michael S. Tsirkin" cc: Gleb Natapov , Benjamin Herrenschmidt , Petr Vandrovec , Nick Piggin , Badari Pulavarty , Linux Kernel Mailing List Subject: Re: Nick's core remove PageReserved broke vmware... In-Reply-To: <20051103143713.GB31134@mellanox.co.il> Message-ID: References: <20051103143713.GB31134@mellanox.co.il> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 03 Nov 2005 15:00:51.0259 (UTC) FILETIME=[619998B0:01C5E087] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1321 Lines: 27 On Thu, 3 Nov 2005, Michael S. Tsirkin wrote: > All existing drivers that set VM_DONTCOPY also set VM_IO. > So lets just disable playing with these flags from madvise if VM_IO is set. > There's no reason I can see that the driver should have a say > on what the process does with its own (non-IO) memory. > Sounds good? You're then saying that a process cannot set VM_DONTCOPY on a VM_IO area to prevent the first child getting the area, but clear it after so the next child does get a copy of the area. I think it'd be wrong (surprising) to limit the functionality in that way. > 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? Hugh - 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/