From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161097AbXBGJfw (ORCPT ); Wed, 7 Feb 2007 04:35:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161092AbXBGJfw (ORCPT ); Wed, 7 Feb 2007 04:35:52 -0500 Received: from smtp-out.google.com ([216.239.45.13]:21176 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161097AbXBGJfu (ORCPT ); Wed, 7 Feb 2007 04:35:50 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:date:from:x-x-sender:to:cc:subject:in-reply-to: message-id:references:mime-version:content-type; b=cLSBPJUXrGcOSPkcqA0AB7O4OcATl8hITi8WJe/LpdA9SQdAdwEMV6VVYAaPX8du7 hPhZVyPelS0oG8mco9eYQ== Date: Wed, 7 Feb 2007 01:35:31 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Christoph Lameter cc: Andrew Morton , Hugh Dickins , Paul Mundt , Paul Davies , linux-kernel@vger.kernel.org Subject: Re: [patch 1/3 take2] smaps: extract pte walker from smaps code In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Feb 2007, Christoph Lameter wrote: > Clearing reference bits? Ummm... That is a pretty inaccurate measure since > reclaim can remove pages and revert the reference bits. It can never work > reliably. > It's not intended to work precisely, it's intended to give a good estimate of task memory footprint. There are several different scenarios that can interfere with getting a precise measurement via this method; then again /proc/pid/smaps is so expensive already because of the iteration through VMA's that it's not something you'd do regularly. Any other suggestions on how to obtain this data is certainly welcome. > Would it be possible to sync up with the people doing the page table > interface? > (+pauld) Is there an update on Paul Davies' implementation that would allow us to iterate through a set of pte's in a vm_area_struct range? > Could we somehow consolidate smaps and numa_maps? > Sure, but that's beyond the scope of this patchset. My intention in extracting away a new pte_walker was to prevent having two identical implementations and it could easily be extracted even further to lib for the ioremap case that Paul mentioned. David