From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422823AbXCBED0 (ORCPT ); Thu, 1 Mar 2007 23:03:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422834AbXCBED0 (ORCPT ); Thu, 1 Mar 2007 23:03:26 -0500 Received: from smtp.osdl.org ([65.172.181.24]:40496 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422823AbXCBEDZ (ORCPT ); Thu, 1 Mar 2007 23:03:25 -0500 Date: Thu, 1 Mar 2007 19:59:43 -0800 From: Andrew Morton To: Linus Torvalds Cc: Balbir Singh , Mel Gorman , npiggin@suse.de, clameter@engr.sgi.com, mingo@elte.hu, jschopp@austin.ibm.com, arjan@infradead.org, mbligh@mbligh.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: The performance and behaviour of the anti-fragmentation related patches Message-Id: <20070301195943.8ceb221a.akpm@linux-foundation.org> In-Reply-To: References: <20070301101249.GA29351@skynet.ie> <20070301160915.6da876c5.akpm@linux-foundation.org> <45E7835A.8000908@in.ibm.com> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 1 Mar 2007 19:44:27 -0800 (PST) Linus Torvalds wrote: > In other words, I really don't see a huge upside. I see *lots* of > downsides, but upsides? Not so much. Almost everybody who wants unplug > wants virtualization, and right now none of the "big virtualization" > people would want to have kernel-level anti-fragmentation anyway sicne > they'd need to do it on their own. Agree with all that, but you're missing the other application: power saving. FBDIMMs take eight watts a pop. If we can turn them off when the system is unloaded we save either four or all eight watts (assuming we can get Intel to part with the information which is needed to do this. I fear an ACPI method will ensue). There's a whole lot of complexity and work in all of this, but 24*8 watts is a lot of watts, and it's worth striving for.