From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754182AbZEXNpJ (ORCPT ); Sun, 24 May 2009 09:45:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752305AbZEXNo6 (ORCPT ); Sun, 24 May 2009 09:44:58 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:36223 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750908AbZEXNo5 (ORCPT ); Sun, 24 May 2009 09:44:57 -0400 Date: Sun, 24 May 2009 22:44:30 +0900 (JST) From: KOSAKI Motohiro To: Christoph Lameter Subject: Re: [PATCH 4/4] zone_reclaim_mode is always 0 by default Cc: kosaki.motohiro@jp.fujitsu.com, Robin Holt , LKML , linux-mm , Andrew Morton , Rik van Riel In-Reply-To: References: <20090521090549.63B5.A69D9226@jp.fujitsu.com> Message-Id: <20090524223857.0852.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sorry I missed this mail > > > Even with 128 nodes and 256 cpus, I _NEVER_ see the > > > system swapping out before allocating off node so I can certainly not > > > reproduce the situation you are seeing. > > > > hmhm. but I don't think we can assume hpc workload. > > System swapping due to zone reclaim? zone reclaim only reclaims unmapped > pages so it will not swap. Maybe some bug crept in in the recent changes? > Or you overrode the defaults for zone reclaim? I guess he use zone_reclaim_mode=7 or similar. However, I have to explain recent zone reclaim change. current zone reclaim is 1. zone reclaim can make high order reclaim (by hanns) 2. determine file-backed page by get_scan_ratio it mean, high order allocation makes lumpy zone reclaim. and shrink_inactive_list() don't care may_swap. then, zone_reclaim_mode=1 can makes swap-out if your driver makes high order allocation request.