From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com [32.97.182.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e1.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 32035B6F7D for ; Wed, 5 Oct 2011 01:37:44 +1100 (EST) Received: from /spool/local by us.ibm.com with XMail ESMTP for from ; Tue, 4 Oct 2011 10:36:11 -0400 Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p94EQfjx198780 for ; Tue, 4 Oct 2011 10:35:26 -0400 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p94EJ4Ud002545 for ; Tue, 4 Oct 2011 08:19:04 -0600 Message-ID: <4E8B15D4.9080104@austin.ibm.com> Date: Tue, 04 Oct 2011 09:19:00 -0500 From: Nathan Fontenot MIME-Version: 1.0 To: Andrew Morton 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 Cc: Greg KH , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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