From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261520AbVFAX7j (ORCPT ); Wed, 1 Jun 2005 19:59:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261507AbVFAX6R (ORCPT ); Wed, 1 Jun 2005 19:58:17 -0400 Received: from smtp207.mail.sc5.yahoo.com ([216.136.129.97]:41862 "HELO smtp207.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261523AbVFAX4e (ORCPT ); Wed, 1 Jun 2005 19:56:34 -0400 Message-ID: <429E4B22.5080404@yahoo.com.au> Date: Thu, 02 Jun 2005 09:56:18 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.6) Gecko/20050324 Debian/1.7.6-1 X-Accept-Language: en MIME-Version: 1.0 To: Mike Kravetz CC: jschopp@austin.ibm.com, Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: Avoiding external fragmentation with a placement policy Version 12 References: <20050531112048.D2511E57A@skynet.csn.ul.ie> <429E20B6.2000907@austin.ibm.com> <429E4023.2010308@yahoo.com.au> <20050601234730.GF3998@w-mikek2.ibm.com> In-Reply-To: <20050601234730.GF3998@w-mikek2.ibm.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mike Kravetz wrote: > On Thu, Jun 02, 2005 at 09:09:23AM +1000, Nick Piggin wrote: > >>It adds a lot of complexity to the page allocator and while >>it might be very good, the only improvement we've been shown >>yet is allocating lots of MAX_ORDER allocations I think? (ie. >>not very useful) >> > > > Allocating lots of MAX_ORDER blocks can be very useful for things > like hot-pluggable memory. I know that this may not be of interest > to most. However, I've been combining Mel's defragmenting patch > with the memory hotplug patch set. As a result, I've been able to > go from 5GB down to 544MB of memory on my ppc64 system via offline > operations. Note that ppc64 only employs a single (DMA) zone. So, > page 'grouping' based on use is coming mainly from Mel's patch. > Back in the day, Linus would tell you to take a hike if you wanted to complicate the buddy allocator to better support memory hotplug ;) I don't know what's happened to him now though, he seems to have gone a little soft on you enterprise types. Seriously - thanks for the data point, I had an idea that you guys wanted this for mem hotplug. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com