From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397AbXCXGWT (ORCPT ); Sat, 24 Mar 2007 02:22:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751904AbXCXGWS (ORCPT ); Sat, 24 Mar 2007 02:22:18 -0400 Received: from smtp.osdl.org ([65.172.181.24]:56768 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753465AbXCXGWS (ORCPT ); Sat, 24 Mar 2007 02:22:18 -0400 Date: Fri, 23 Mar 2007 22:21:33 -0800 From: Andrew Morton To: Christoph Lameter Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [QUICKLIST 1/5] Quicklists for page table pages V4 Message-Id: <20070323222133.f17090cf.akpm@linux-foundation.org> In-Reply-To: References: <20070323062843.19502.19827.sendpatchset@schroedinger.engr.sgi.com> <20070322223927.bb4caf43.akpm@linux-foundation.org> <20070322234848.100abb3d.akpm@linux-foundation.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-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 On Fri, 23 Mar 2007 10:54:12 -0700 (PDT) Christoph Lameter wrote: > Here are the results of aim9 tests on x86_64. There are some minor performance > improvements and some fluctuations. There are a lot of numbers there - what do they tell us? > 2.6.21-rc4 bare > 2.6.21-rc4 x86_64 quicklist So what has changed here? From a quick look it appears that x86_64 is using get_zeroed_page() for ptes, puds and pmds and is using a custom quicklist for pgds. After your patches, x86_64 is using a common quicklist allocator for puds, pmds and pgds and continues to use get_zeroed_page() for ptes. Or something totally different, dunno. I tire. My question is pretty simple: how do we justify the retention of this custom allocator? Because simply removing it is the preferable way of fixing the SLUB problem.