Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265614AbTIDWLS (ORCPT ); Thu, 4 Sep 2003 18:11:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265615AbTIDWK4 (ORCPT ); Thu, 4 Sep 2003 18:10:56 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:8333 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S265614AbTIDWKj (ORCPT ); Thu, 4 Sep 2003 18:10:39 -0400 Date: Thu, 4 Sep 2003 23:10:11 +0100 From: Jamie Lokier To: Linus Torvalds Cc: Hugh Dickins , Rusty Russell , Andrew Morton , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Alternate futex non-page-pinning and COW fix Message-ID: <20030904221011.GJ31590@mail.jlokier.co.uk> References: <20030904200426.GB31590@mail.jlokier.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1124 Lines: 31 Linus Torvalds wrote: > > * A futex on a MAP_PRIVATE must be mm-local: the canonical > > * example being MAP_PRIVATE of /dev/zero. > > Actually, /dev/zero is a special case in itself. It is an anonymous > mapping, and is equivalent to MAP_ANON for private mappings. For > MAP_SHARED it is something _totally_ different. Well yes, but conceptually it's behaviour is that of a private mapping of a file-like object. But fine, let's not get sidetracked by /dev/zero. I'll restate it: * A futex on a MAP_PRIVATE must be mm-local. The canonical example being the data section of your executable. > > Unfortunately I think the above 5 conditions do not have a consistent > > solution. Please prove me wrong :) > > I don't think there is any inconsistency. I can't think of a behaviour which satisfies all 5 conditions, so you'll have to help me out. :/ -- 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/