Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754346AbZJAPQv (ORCPT ); Thu, 1 Oct 2009 11:16:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754162AbZJAPQv (ORCPT ); Thu, 1 Oct 2009 11:16:51 -0400 Received: from gir.skynet.ie ([193.1.99.77]:43144 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750971AbZJAPQu (ORCPT ); Thu, 1 Oct 2009 11:16:50 -0400 Date: Thu, 1 Oct 2009 16:16:57 +0100 From: Mel Gorman To: Christoph Lameter Cc: Pekka Enberg , Nick Piggin , heiko.carstens@de.ibm.com, sachinp@in.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Tejun Heo , Benjamin Herrenschmidt Subject: Re: [PATCH 2/4] slqb: Record what node is local to a kmem_cache_cpu Message-ID: <20091001151657.GH21906@csn.ul.ie> References: <84144f020909221154x820b287r2996480225692fad@mail.gmail.com> <20090922185608.GH25965@csn.ul.ie> <20090930144117.GA17906@csn.ul.ie> <20090930220541.GA31530@csn.ul.ie> <20091001104046.GA21906@csn.ul.ie> <20091001150346.GD21906@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: 1436 Lines: 33 On Thu, Oct 01, 2009 at 11:03:16AM -0400, Christoph Lameter wrote: > On Thu, 1 Oct 2009, Mel Gorman wrote: > > > True, it might have been improved more if SLUB knew what local hugepage it > > resided within as the kernel portion of the address space is backed by huge > > TLB entries. Note that SLQB could have an advantage here early in boot as > > the page allocator will tend to give it back pages within a single huge TLB > > entry. It loses the advantage when the system has been running for a very long > > time but it might be enough to skew benchmark results on cold-booted systems. > > The page allocator serves pages aligned to huge page boundaries as far as > I can remember. You're right, it does, particularly early in boot. It loses the advantage when the system has been running a long time and memory is mostly full but the same will apply to SLQB. > You can actually use huge pages in slub if you set the max > order to 9. So a page obtained from the page allocator is always aligned > properly. > Fair point. -- 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/