Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265612AbTGDBUF (ORCPT ); Thu, 3 Jul 2003 21:20:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265613AbTGDBUF (ORCPT ); Thu, 3 Jul 2003 21:20:05 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:40330 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S265612AbTGDBUC (ORCPT ); Thu, 3 Jul 2003 21:20:02 -0400 Date: Fri, 4 Jul 2003 02:33:45 +0100 From: Jamie Lokier To: Andrea Arcangeli Cc: William Lee Irwin III , "Martin J. Bligh" , Mel Gorman , Linux Memory Management List , Linux Kernel Mailing List Subject: Re: What to expect with the 2.6 VM Message-ID: <20030704013345.GA18928@mail.jlokier.co.uk> References: <20030702233014.GW23578@dualathlon.random> <20030702235540.GK26348@holomorphy.com> <20030703113144.GY23578@dualathlon.random> <20030703114626.GP26348@holomorphy.com> <20030703125839.GZ23578@dualathlon.random> <20030703184825.GA17090@mail.jlokier.co.uk> <20030703185431.GQ26348@holomorphy.com> <20030703193328.GN23578@dualathlon.random> <20030703222113.GS26348@holomorphy.com> <20030704004641.GR23578@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030704004641.GR23578@dualathlon.random> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 895 Lines: 20 Andrea Arcangeli wrote: > so you agree it'd better be a separate syscall Per-page protections might be workable just through mremap(). As you say, it's just a matter of appropriate bits in the swap entry. To userspace it is a transparent performance improvement. Unfortunately without an appropriate bit in the pte too, that restricts per-page protections to work only with shared mappings, or anon mappings which have not been forked, due to the lack of COW. It would still be a good optimisation, although it would be a shame if, say, a GC implementation of malloc et al. (eg. Boehm's allocator) would not be transparent over fork(). -- Jamie - 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/