From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964917AbXCBBwh (ORCPT ); Thu, 1 Mar 2007 20:52:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965061AbXCBBwh (ORCPT ); Thu, 1 Mar 2007 20:52:37 -0500 Received: from ausmtp04.au.ibm.com ([202.81.18.152]:33870 "EHLO ausmtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964917AbXCBBwh (ORCPT ); Thu, 1 Mar 2007 20:52:37 -0500 Message-ID: <45E7835A.8000908@in.ibm.com> Date: Fri, 02 Mar 2007 07:22:26 +0530 From: Balbir Singh Reply-To: balbir@in.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.9 (X11/20070103) MIME-Version: 1.0 To: Linus Torvalds CC: Andrew Morton , 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 References: <20070301101249.GA29351@skynet.ie> <20070301160915.6da876c5.akpm@linux-foundation.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > On Thu, 1 Mar 2007, Andrew Morton wrote: >> So some urgent questions are: how are we going to do mem hotunplug and >> per-container RSS? > > Also: how are we going to do this in virtualized environments? Usually the > people who care abotu memory hotunplug are exactly the same people who > also care (or claim to care, or _will_ care) about virtualization. > > My personal opinion is that while I'm not a huge fan of virtualization, > these kinds of things really _can_ be handled more cleanly at that layer, > and not in the kernel at all. Afaik, it's what IBM already does, and has > been doing for a while. There's no shame in looking at what already works, > especially if it's simpler. Could you please clarify as to what "that layer" means - is it the firmware/hardware for virtualization? or does it refer to user space? With virtualization the linux kernel would end up acting as a hypervisor and resource management support like per-container RSS support needs to be built into the kernel. It would also be useful to have a resource controller like per-container RSS control (container refers to a task grouping) within the kernel or non-virtualized environments as well. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL