From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261671AbVGGBVU (ORCPT ); Wed, 6 Jul 2005 21:21:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262370AbVGGBTI (ORCPT ); Wed, 6 Jul 2005 21:19:08 -0400 Received: from smtp.osdl.org ([65.172.181.4]:27820 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S262343AbVGGBRE (ORCPT ); Wed, 6 Jul 2005 21:17:04 -0400 Date: Wed, 6 Jul 2005 18:16:23 -0700 From: Andrew Morton To: P@draigBrady.com Cc: linux-kernel@vger.kernel.org Subject: Re: How do you accurately determine a process' RAM usage? Message-Id: <20050706181623.3729d208.akpm@osdl.org> In-Reply-To: <42CC2923.2030709@draigBrady.com> References: <42CC2923.2030709@draigBrady.com> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org P@draigBrady.com wrote: > > I wrote a tool to report how much RAM a > particular program (apache for e.g.) was using: > http://www.pixelbeat.org/scripts/ps_mem.py > > I was then pointed at the following: > http://wiki.apache.org/spamassassin/TopSharedMemoryBug > which describes how copy-on-write pages are > not counted as shared since 2.6. > > So how can one determine how much RAM a process is using? > Seems like a fundamental requirement to me. > Could we add a "SharedTotal" column to /proc/$$/statm for e.g. ? Calculating this stuff accurately is very expensive. You'll get a better answer using proc-pid-smaps.patch from -mm, but even that won't tell you things about sharing levels of the pages.