From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753169AbXDMJqR (ORCPT ); Fri, 13 Apr 2007 05:46:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753174AbXDMJqR (ORCPT ); Fri, 13 Apr 2007 05:46:17 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:37436 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753169AbXDMJqR (ORCPT ); Fri, 13 Apr 2007 05:46:17 -0400 Date: Fri, 13 Apr 2007 10:46:10 +0100 From: Christoph Hellwig To: Nick Piggin Cc: Christoph Hellwig , William Lee Irwin III , Andrew Morton , Matt Mackall , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/13] maps: pagemap, kpagemap, and related cleanups Message-ID: <20070413094610.GA8875@infradead.org> Mail-Followup-To: Christoph Hellwig , Nick Piggin , William Lee Irwin III , Andrew Morton , Matt Mackall , linux-kernel@vger.kernel.org References: <20070412185723.5a5f0443.akpm@linux-foundation.org> <461EE890.2040601@yahoo.com.au> <20070412193255.62a0b8ed.akpm@linux-foundation.org> <461EEFEC.2010205@yahoo.com.au> <20070413065357.GP2986@holomorphy.com> <461F2BCB.2020200@yahoo.com.au> <20070413075142.GA23822@infradead.org> <461F3961.6030300@yahoo.com.au> <20070413081338.GA27675@infradead.org> <461F3E8A.9010902@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <461F3E8A.9010902@yahoo.com.au> User-Agent: Mutt/1.4.2.2i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 13, 2007 at 06:25:46PM +1000, Nick Piggin wrote: > But at least make it into its own module with a debugfs interface or > something. I mean, exposing a PG_name-to-nr and page count pfn and flags > as a supposedly formal proc interface doesn't sound nice to me. Page > flags does not tell you what is going on in the VM, it gives you a tiny > window into "something". Between reading a /proc/pid/ pfn and finding > the pfn's page flags, it could be used for something completely different > anyway. I agree that exposing numerical values of page flags is not a very good idea at all. If we really want to expose this information it should at least be in string form, although that is quite a bit of a maintaince horror aswell.