From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992659AbXCBR2X (ORCPT ); Fri, 2 Mar 2007 12:28:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992662AbXCBR2X (ORCPT ); Fri, 2 Mar 2007 12:28:23 -0500 Received: from calculon.skynet.ie ([193.1.99.88]:34268 "EHLO calculon.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992659AbXCBR2W (ORCPT ); Fri, 2 Mar 2007 12:28:22 -0500 Date: Fri, 2 Mar 2007 17:28:18 +0000 To: Christoph Lameter Cc: Andrew Morton , npiggin@suse.de, mingo@elte.hu, jschopp@austin.ibm.com, arjan@infradead.org, torvalds@linux-foundation.org, mbligh@mbligh.org, kamezawa.hiroyu@jp.fujitsu.com, linux-kernel@vger.kernel.org Subject: Re: The performance and behaviour of the anti-fragmentation related patches Message-ID: <20070302172818.GA15730@skynet.ie> References: <20070301101249.GA29351@skynet.ie> <20070301160915.6da876c5.akpm@linux-foundation.org> <20070302163206.GA1555@skynet.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i From: mel@skynet.ie (Mel Gorman) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On (02/03/07 09:19), Christoph Lameter didst pronounce: > On Fri, 2 Mar 2007, Mel Gorman wrote: > > > However, if that is objectionable, I'd at least like to see zone-based patches > > go into -mm on the expectation that the memory hot-remove patches will be > > able to use the infrastructure. It's not ideal for hugepages and it is not my > > first preference, but it's a step in the right direction. Is this reasonable? > > I still think that the list based approach is sufficient for memory > hotplug if one restricts the location of the unmovable MAX_ORDER chunks > to not overlap the memory area where we would like to be able to remove > memory. Yes, true. In the part where I bias placements of unmovable pages at lower PFNs, additional steps would need to be taken. Specifically, the lowest block MAX_ORDER_NR_PAGES used for movable pages would need to be reclaimed for unmovable allocations. > In very pressing memory situations where we have too much > unmovable memory we could dynamically disable memory hotplug. There > would be no need for this partitioning and additional zones. > It's simply more complex. I believe it's doable. The main plus going for the zone is that it is a clearly understood concept and it gives hard guarantees. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab