From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756075AbZBEKlw (ORCPT ); Thu, 5 Feb 2009 05:41:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752415AbZBEKll (ORCPT ); Thu, 5 Feb 2009 05:41:41 -0500 Received: from gir.skynet.ie ([193.1.99.77]:41678 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751377AbZBEKlk (ORCPT ); Thu, 5 Feb 2009 05:41:40 -0500 Date: Thu, 5 Feb 2009 10:41:38 +0000 From: Mel Gorman To: David Miller Cc: kamezawa.hiroyu@jp.fujitsu.com, heiko.carstens@de.ibm.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org Subject: Re: HOLES_IN_ZONE... Message-ID: <20090205104138.GF26878@csn.ul.ie> References: <20090204.222651.26527737.davem@davemloft.net> <20090205101023.GD26878@csn.ul.ie> <20090205.021429.170975463.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090205.021429.170975463.davem@davemloft.net> 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 On Thu, Feb 05, 2009 at 02:14:29AM -0800, David Miller wrote: > From: Mel Gorman > Date: Thu, 5 Feb 2009 10:10:23 +0000 > > > On Wed, Feb 04, 2009 at 10:26:51PM -0800, David Miller wrote: > > > As a suggestion, it would have been a lot more pleasant if the code > > > validated this requirement (in the !HOLES_IN_ZONE case) at boot time > > > instead of after 2 hours of stress testing :-( > > > > > > > Nice maybe, but we'd take a hit on pfn_valid_within() which goes from > > being compiled-away on architectures that don't need it to being > > a read of a shared cacheline and a branch. > > I said at boot time Mel, not in the fast paths. pfn_valid_within() is not used in any critical paths, but it's used in the page free path so it would be a hit there. > Meaning, we'd > check it after all the available ranges get registered and > tossed into the free page lists. > It's not a free-list problem, it's walkers of PFN ranges. Anyway, it's not important to the current problem. > Anyways, it appears we have a fix already, read the rest of > the thread. > Yes. Thanks Kamezawa Hiroyu for the fix. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab