From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752135AbXCZLp2 (ORCPT ); Mon, 26 Mar 2007 07:45:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752140AbXCZLp2 (ORCPT ); Mon, 26 Mar 2007 07:45:28 -0400 Received: from mx1.redhat.com ([66.187.233.31]:36141 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135AbXCZLp0 (ORCPT ); Mon, 26 Mar 2007 07:45:26 -0400 From: David Howells In-Reply-To: References: <20070326024143.a226c9b2.akpm@linux-foundation.org> <1174904637.32691.86.camel@roc-desktop> <6017.1174908318@redhat.com> To: Pekka J Enberg Cc: Andrew Morton , bryan.wu@analog.com, linux-kernel@vger.kernel.org, Hugh Dickins , dhowells@redhat.com Subject: Re: [PATCH -mm] Revoke core code: fix nommu arch compiling error bug X-Mailer: MH-E 8.0; nmh 1.1; GNU Emacs 22.0.50 Date: Mon, 26 Mar 2007 12:44:19 +0100 Message-ID: <6791.1174909459@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Pekka J Enberg wrote: > But what's more important is, can we do revoke_mapping() for NOMMU? AFAICT > we can, we just need to scan all the global vmas, right? I don't know, what does it do? Remember, once a NOMMU process thinks it has the right to access a mapping, there's no way of stopping it doing so short of killing the process. With NOMMU as it stands, private mappings are private copies of the data, and have no impact on the page cache and get no updates from it. It's as if you took a private writable mapping, touched every page and then mprotect()'d it. This isn't necessarily ideal, but we're limited by the lack on an MMU. David