From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761426AbXGKJer (ORCPT ); Wed, 11 Jul 2007 05:34:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756900AbXGKJeh (ORCPT ); Wed, 11 Jul 2007 05:34:37 -0400 Received: from hellhawk.shadowen.org ([80.68.90.175]:2511 "EHLO hellhawk.shadowen.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756690AbXGKJeg (ORCPT ); Wed, 11 Jul 2007 05:34:36 -0400 Message-ID: <4694A427.7070708@shadowen.org> Date: Wed, 11 Jul 2007 10:34:31 +0100 From: Andy Whitcroft User-Agent: Icedove 1.5.0.9 (X11/20061220) MIME-Version: 1.0 To: Andy Whitcroft CC: Andrew Morton , linux-kernel@vger.kernel.org, Mel Gorman , Christoph Lameter , Peter Zijlstra Subject: Re: Re: -mm merge plans -- lumpy reclaim References: <20070710013152.ef2cd200.akpm@linux-foundation.org> <46937DA2.4040302@shadowen.org> In-Reply-To: <46937DA2.4040302@shadowen.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [Seems a PEBKAC occured on the subject line, resending lest it become a victim of "oh thats spam".] Andy Whitcroft wrote: > Andrew Morton wrote: > > [...] >> lumpy-reclaim-v4.patch >> have-kswapd-keep-a-minimum-order-free-other-than-order-0.patch >> only-check-absolute-watermarks-for-alloc_high-and-alloc_harder-allocations.patch >> >> Lumpy reclaim. In a similar situation to Mel's patches. Stuck due to >> general lack or interest and effort. > > The lumpy reclaim patches originally came out of work to support Mel's > anti-fragmentation work. As such I think they have become somewhat > attached to those patches. Whilst lumpy is most effective where > placement controls are in place as offered by Mel's work, we see benefit > from reduction in the "blunderbuss" effect when we reclaim at higher > orders. While placement control is pretty much required for the very > highest orders such as huge page size, lower order allocations are > benefited in terms of lower collateral damage. > > There are now a few areas other than huge page allocations which can > benefit. Stacks are still order 1. Jumbo frames want higher order > contiguous pages for there incoming hardware buffers. SLUB is showing > performance benefits from moving to a higher allocation order. All of > these should benefit from more aggressive targeted reclaim, indeed I > have been surprised just how often my test workloads trigger lumpy at > order 1 to get new stacks. > > Truly representative work loads are hard to generate for some of these. > Though we have heard some encouraging noises from those who can > reproduce these problems. > > [...] > > -apw