From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966775AbXEHUi4 (ORCPT ); Tue, 8 May 2007 16:38:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934099AbXEHUiz (ORCPT ); Tue, 8 May 2007 16:38:55 -0400 Received: from atlrel8.hp.com ([156.153.255.206]:47413 "EHLO atlrel8.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933865AbXEHUiy (ORCPT ); Tue, 8 May 2007 16:38:54 -0400 Subject: Re: [PATCH] change zonelist order v5 [1/3] implements zonelist order selection From: Lee Schermerhorn To: Christoph Lameter Cc: KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, ak@suse.de, jbarnes@virtuousgeek.org In-Reply-To: References: <20070508201401.8f78ec37.kamezawa.hiroyu@jp.fujitsu.com> <20070508201642.c63b3f65.kamezawa.hiroyu@jp.fujitsu.com> <1178643985.5203.27.camel@localhost> <1178645622.5203.53.camel@localhost> Content-Type: text/plain Organization: HP/OSLO Date: Tue, 08 May 2007 16:37:06 -0400 Message-Id: <1178656627.5203.84.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2007-05-08 at 11:05 -0700, Christoph Lameter wrote: > On Tue, 8 May 2007, Lee Schermerhorn wrote: > > > > So far testing is IA64 only? > > Yes, so far. I will test on an Opteron platform this pm. > > Assume that no news is good news. > > A better assumption: no news -> no testing. Before you asked, yes. I meant after the last message, if you didn't hear from me, everything worked fine. And it does, sort of... > You probably need a > configuration with a couple of nodes. Maybesomething less symmetric than > Kame? I.e. have 4GB nodes and then DMA32 takes out a sizeable chunk of it? > I tested on a 2 socket, 4GB Opteron blade. All memory is either DMA32 or DMA. I added some ad hoc instrumentation to the build_zonelist_* functions to see what's happening. I have verified that the patches appear to build the zonelists correctly: default -> node order, because "low_kmem" [DMA+DMA32] > total_mem/2. Zone lists: DMA: DMA-0 DMA32: DMA32-0, DMA-0, DMA32-1 Normal: same as DMA32 [no normal memory] Movable: same as DMA32 & Normal explicit zone order also builds as expected: DMA: DMA-0 DMA32: DMA32-1, DMA32-0, DMA-0 and same for normal and movable However, a curious thing happens: in either order, allocations seem to overflow to the remote DMA32 before dipping into the DMA!!!? I'm using memtoy to create a large [3+GB] anon segment and locking it down. I need to check a non-patched kernel to see if it behaves the same way, and examine the code to see why... For one thing, the kernel seems to do a bit better at reclaiming memory before overflowing. Eventually, it will dip into DMA and finally get killed--OOM. I'll be off-line most of the rest of the week, so I probably won't get to investigate much further nor test on a larger socket count/memory system until next week. Lee