From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757259Ab1JDOT2 (ORCPT ); Tue, 4 Oct 2011 10:19:28 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:38348 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756652Ab1JDOT1 (ORCPT ); Tue, 4 Oct 2011 10:19:27 -0400 Message-ID: <4E8B15D4.9080104@austin.ibm.com> Date: Tue, 04 Oct 2011 09:19:00 -0500 From: Nathan Fontenot User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.23) Gecko/20110921 Thunderbird/3.1.15 MIME-Version: 1.0 To: Andrew Morton CC: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Greg KH Subject: Re: [PATCH] memory hotplug: Correct page reservation checking References: <4E8098B9.1080702@austin.ibm.com> <20111003175022.50cbef7f.akpm00@gmail.com> In-Reply-To: <20111003175022.50cbef7f.akpm00@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 11100414-8974-0000-0000-0000009F429E Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/03/2011 07:50 PM, Andrew Morton wrote: > On Mon, 26 Sep 2011 10:22:33 -0500 > Nathan Fontenot wrote: > >> The check to ensure that pages of recently added memory sections are correctly >> marked as reserved before trying to online the memory is broken. The request >> to online the memory fails with the following: >> >> kernel: section number XXX page number 256 not reserved, was it already online? >> >> This updates the page reservation checking to check the pages of each memory >> section of the memory block being onlined individually. > > Why was this only noticed now? Is there something unusual about the > way in which you're using it, or has nobody ever used this code, or...? > As far as I know it is only the powerpc/pseries code that uses the feature that allows memory blocks in sysfs to span multiple memory sections. We do this because on pseries memory add/remove is done on a per LMB basis and we can have machine where an LMB spans multiple memory sections. This was just noticed due to a lack of testing between the 2.6.38/39 kernels where this feature originally went in and the current mainline kernel. -Nathan