Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758963AbZCTQ12 (ORCPT ); Fri, 20 Mar 2009 12:27:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756189AbZCTQ1U (ORCPT ); Fri, 20 Mar 2009 12:27:20 -0400 Received: from gir.skynet.ie ([193.1.99.77]:43156 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753190AbZCTQ1T (ORCPT ); Fri, 20 Mar 2009 12:27:19 -0400 Date: Fri, 20 Mar 2009 16:27:16 +0000 From: Mel Gorman To: Christoph Lameter Cc: Linux Memory Management List , KOSAKI Motohiro , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra , Andrew Morton Subject: Re: [PATCH 00/25] Cleanup and optimise the page allocator V5 Message-ID: <20090320162716.GP24586@csn.ul.ie> References: <1237543392-11797-1-git-send-email-mel@csn.ul.ie> <20090320153723.GO24586@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1386 Lines: 37 On Fri, Mar 20, 2009 at 12:07:22PM -0400, Christoph Lameter wrote: > On Fri, 20 Mar 2009, Mel Gorman wrote: > > > good idea one way or the other. Course, this meant a search of the PCP > > lists or increasing the size of the PCP structure - swings and > > roundabouts :/ > > The PCP list structure irks me a bit. Manipulating doubly linked lists > means touching at least 3 cachelines. Yeah, and bloats the structure quite a bit. It's what hits the one-list-per-migratetype the hardest. > Is it possible to go to a simple > linked list (one cacheline to be touched)? I considered it but it breaks the hot/cold allocation/freeing logic and the search code became weird enough looking fast enough that I dropped it. > Or an array of pointers to > pages instead (one cacheline may contian multiple pointers to pcp pages > which means multiple pages could be handled with a single cacheline)? > An array of pointers is promising but it would bloat the structure quiet a bit too. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/