From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754417Ab1GFJbx (ORCPT ); Wed, 6 Jul 2011 05:31:53 -0400 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:49960 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753954Ab1GFJbw (ORCPT ); Wed, 6 Jul 2011 05:31:52 -0400 Date: Wed, 6 Jul 2011 15:01:46 +0530 From: Ankita Garg To: Andrew Morton Cc: linux-mm@kvack.org, svaidy@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Matt Mackall Subject: Re: [PATCH 0/5] mm,debug: VM framework to capture memory reference pattern Message-ID: <20110706093146.GB19518@in.ibm.com> Reply-To: Ankita Garg References: <1309854159-8277-1-git-send-email-ankita@in.ibm.com> <20110706020103.53ed8706.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110706020103.53ed8706.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, Jul 06, 2011 at 02:01:03AM -0700, Andrew Morton wrote: > On Tue, 5 Jul 2011 13:52:34 +0530 Ankita Garg wrote: > > > > > This patch series is an instrumentation/debug infrastructure that captures > > the memory reference pattern of applications (workloads). > > Can't the interfaces described in Documentation/vm/pagemap.txt be used > for this? The pagemap interface does not closely track the hardware reference bit of the pages. The 'REFERENCED' flag maintained in /proc/kpageflags only indicates if the page has been referenced since last LRU list enqueue/requeue. So estimating the rate at which a particular page of memory is referenced cannot be obtained. Further, it does not provide information on the amount of kernel memory referenced on behalf of the process. -- Regards, Ankita Garg (ankita@in.ibm.com) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India