From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id C31196B0012 for ; Mon, 2 May 2011 18:19:31 -0400 (EDT) Received: (from localhost user: 'dkiper' uid#4000 fake: STDIN (dkiper@router-fw.net-space.pl)) by router-fw-old.local.net-space.pl id S1581921Ab1EBWS5 (ORCPT ); Tue, 3 May 2011 00:18:57 +0200 Date: Tue, 3 May 2011 00:18:57 +0200 From: Daniel Kiper Subject: Re: [PATCH 1/4] mm: Remove dependency on CONFIG_FLATMEM from online_page() Message-ID: <20110502221857.GJ4623@router-fw-old.local.net-space.pl> References: <20110502211915.GB4623@router-fw-old.local.net-space.pl> <1304371504.30823.45.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1304371504.30823.45.camel@nimitz> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Daniel Kiper , ian.campbell@citrix.com, akpm@linux-foundation.org, andi.kleen@intel.com, haicheng.li@linux.intel.com, fengguang.wu@intel.com, jeremy@goop.org, konrad.wilk@oracle.com, dan.magenheimer@oracle.com, v.tolstov@selfip.ru, pasik@iki.fi, wdauchy@gmail.com, rientjes@google.com, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, May 02, 2011 at 02:25:04PM -0700, Dave Hansen wrote: > On Mon, 2011-05-02 at 23:19 +0200, Daniel Kiper wrote: > > Memory hotplug code strictly depends on CONFIG_SPARSEMEM. > > It means that code depending on CONFIG_FLATMEM in online_page() > > is never compiled. Remove it because it is not needed anymore. > > It's subtle, but I don't think that's true. We had another hotplug mode > for x86_64 before folks were comfortable turning SPARSEMEM on for the > whole architecture. It was quite possible to have memory hotplug > without sparsemem in that case. I think Keith Mannthey did some of that > code if I remember right. > > But, I'm not sure how much of that stayed in distros versus made it > upstream. In any case, you might want to chase down the > X86_64_ACPI_NUMA bit to make sure it can't be used with FLATMEM ever. > > config MEMORY_HOTPLUG > bool "Allow for memory hot-add" > depends on SPARSEMEM || X86_64_ACPI_NUMA > depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG > depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390) IIRC some time ago it was possible to enable memory hotplug with CONFIG_FLATMEM. That is why I looked for any dependencies of memory hoplug code on CONFIG_FLATMEM in current Linux Kernel source. I could not find anything and that is why I published this patch. However, maybe I missed something. Daniel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org