From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752279Ab0F2AEc (ORCPT ); Mon, 28 Jun 2010 20:04:32 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:37888 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989Ab0F2AEb (ORCPT ); Mon, 28 Jun 2010 20:04:31 -0400 Subject: Re: [PATCH] memory hotplug disable boot option From: Dave Hansen To: Greg KH Cc: Nathan Fontenot , KOSAKI Motohiro , Andi Kleen , linux-kernel@vger.kernel.org, "Eric W. Biederman" In-Reply-To: <20100628154455.GA13918@suse.de> References: <87d3vfeage.fsf@basil.nowhere.org> <4C24C279.3050206@austin.ibm.com> <20100628110658.387B.A69D9226@jp.fujitsu.com> <20100628150246.GA13192@suse.de> <4C28C1A8.8010904@austin.ibm.com> <20100628154455.GA13918@suse.de> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Mon, 28 Jun 2010 17:04:27 -0700 Message-ID: <1277769867.8354.531.camel@nimitz> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2010-06-28 at 08:44 -0700, Greg KH wrote: > > The directories being created are the standard directories, one for each of the memory > > sections present at boot. I think the most used files in each of these directories > > is the state and removable file used to do memory hotplug. > > And perhaps we shouldn't really be creating so many directories? Why > not work with the memory hotplug developers to change their interface to > not abuse sysfs in such a manner? Heh, it wasn't abuse until we got this much memory. But, I think this one is pretty much 100% my fault. Nathan, I think the right fix here is probably to untie sysfs from the sections a bit. We should be able to have sysfs dirs that represent more than one contiguous SECTION_SIZE area of memory. It will mean re-teaching some of the tools how things work. They'll have to know that you can split mem sections, and we'll have to come up with a way to do the splitting. Does ppc *really* remove 16MB sections of RAM these days? It's probably worth checking with the firmware folks to see what the limits are in practice. -- Dave