From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761842AbYDCIco (ORCPT ); Thu, 3 Apr 2008 04:32:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757142AbYDCIce (ORCPT ); Thu, 3 Apr 2008 04:32:34 -0400 Received: from cantor2.suse.de ([195.135.220.15]:60208 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755275AbYDCIcc (ORCPT ); Thu, 3 Apr 2008 04:32:32 -0400 Date: Thu, 3 Apr 2008 10:32:31 +0200 From: Nick Piggin To: Pekka Enberg Cc: Linux Memory Management List , Linux Kernel Mailing List , Christoph Lameter Subject: Re: [rfc] SLQB: YASA Message-ID: <20080403083231.GB20132@wotan.suse.de> References: <20080403072550.GC25932@wotan.suse.de> <84144f020804030045p44456894lfc006dcdeab6f67c@mail.gmail.com> <20080403075725.GA7514@wotan.suse.de> <20080403081338.GA18337@wotan.suse.de> <84144f020804030124m4cc0bc1en2e11218f1f8bdc55@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <84144f020804030124m4cc0bc1en2e11218f1f8bdc55@mail.gmail.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 03, 2008 at 11:24:00AM +0300, Pekka Enberg wrote: > Hi Nick, > > On Thu, Apr 03, 2008 at 09:57:25AM +0200, Nick Piggin wrote: > > > It's a completely different design of the core allocator algorithms > > > really. > > > > > > It probably looks quite similar because I started with slub.c, but > > > really is just the peripheral supporting code and structure. I'm never > > > intending to try to go through the pain of incrementally changing SLUB > > > into SLQB. If SLQB is found to be a good idea, then it could maybe get > > > merged. > > On Thu, Apr 3, 2008 at 11:13 AM, Nick Piggin wrote: > > And also I guess I don't think Christoph would be very happy about > > it :) He loves higher order allocations :) > > > > The high level choices are pretty clear and I simply think there might > > be a better way to do it. I'm not saying it *is* better because I simply > > don't know, and there are areas where the tradeoffs I've made means that > > in some situations SLQB cannot match SLUB. > > So do you disagree with Christoph's statement that we should fix page > allocator performance instead of adding queues to SLUB? It's not just adding queues to SLUB, by any means (SLUB effectively already has queues anyway, with it's MIN_PARTIAL thing). I think some page allocator performance can be improved (see my patch to remove the atomic refcounting for example). But in other cases the page allocator just has to do a lot more work and fixing it would just involve removing some of those things. > I also don't > think higher order allocations are the answer for regular boxes but I > can see why they're useful for HPC people with huge machines. I don't disagree with what you say. SLQB doesn't prevent them from being used.