From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753784Ab2DYOml (ORCPT ); Wed, 25 Apr 2012 10:42:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47512 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753487Ab2DYOme (ORCPT ); Wed, 25 Apr 2012 10:42:34 -0400 Message-ID: <4F980D32.8020309@redhat.com> Date: Wed, 25 Apr 2012 10:41:54 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Richard Davies CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Minchan Kim , Wu Fengguang , Balbir Singh , Christoph Lameter , Lee Schermerhorn , Chris Webb Subject: Re: Over-eager swapping References: <20120423092730.GB20543@alpha.arachsys.com> In-Reply-To: <20120423092730.GB20543@alpha.arachsys.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/23/2012 05:27 AM, Richard Davies wrote: > The rrd graphs at http://imgur.com/a/Fklxr show a typical incident. > > We estimate memory used from /proc/meminfo as: > > = MemTotal - MemFree - Buffers + SwapTotal - SwapFree > > The first rrd shows memory used increasing as a VM starts, but not getting > near the 64GB of physical RAM. > > The second rrd shows the heavy swapping this VM start caused. > > The third rrd shows a multi-gigabyte jump in swap used = SwapTotal - SwapFree > > The fourth rrd shows the large load spike (from 1 to 15) caused by this swap > storm. These are exactly the kind of swap storms that led me make the VM tweaks that got merged into 3.4-rc :) See these commits: fe2c2a106663130a5ab45cb0e3414b52df2fff0c 7be62de99adcab4449d416977b4274985c5fe023 aff622495c9a0b56148192e53bdec539f5e147f2 1480de0340a8d5f094b74d7c4b902456c9a06903 496b919b3bdd957d4b1727df79bfa3751bced1c1