From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759374Ab3BWVeK (ORCPT ); Sat, 23 Feb 2013 16:34:10 -0500 Received: from mail-ie0-f172.google.com ([209.85.223.172]:54769 "EHLO mail-ie0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932091Ab3BWVdz convert rfc822-to-8bit (ORCPT ); Sat, 23 Feb 2013 16:33:55 -0500 Date: Sat, 23 Feb 2013 13:26:36 -0600 From: Rob Landley Subject: Re: [Bug fix PATCH 2/2] acpi, movablemem_map: Make whatever nodes the kernel resides in un-hotpluggable. To: Tang Chen Cc: akpm@linux-foundation.org, jiang.liu@huawei.com, wujianguo@huawei.com, hpa@zytor.com, wency@cn.fujitsu.com, laijs@cn.fujitsu.com, linfeng@cn.fujitsu.com, yinghai@kernel.org, isimatu.yasuaki@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com, minchan.kim@gmail.com, mgorman@suse.de, rientjes@google.com, guz.fnst@cn.fujitsu.com, rusty@rustcorp.com.au, lliubbo@gmail.com, jaegeuk.hanse@gmail.com, tony.luck@intel.com, glommer@parallels.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <1361358056-1793-1-git-send-email-tangchen@cn.fujitsu.com> <1361358056-1793-3-git-send-email-tangchen@cn.fujitsu.com> In-Reply-To: <1361358056-1793-3-git-send-email-tangchen@cn.fujitsu.com> (from tangchen@cn.fujitsu.com on Wed Feb 20 05:00:56 2013) X-Mailer: Balsa 2.4.11 Message-Id: <1361647596.11282.7@driftwood> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; DelSp=Yes; Format=Flowed Content-Disposition: inline Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/20/2013 05:00:56 AM, Tang Chen wrote: > There could be several memory ranges in the node in which the kernel > resides. > When using movablemem_map=acpi, we may skip one range that have > memory reserved > by memblock. But if it is too small, then the kernel will fail to > boot. So, make > the whole node which the kernel resides in un-hotpluggable. Then the > kernel has > enough memory to use. > > Reported-by: H Peter Anvin > Signed-off-by: Tang Chen Docs part Acked-by: Rob Landley (with minor non-blocking snark). > @@ -1673,6 +1675,10 @@ bytes respectively. Such letter suffixes can > also be entirely omitted. > satisfied. So the administrator should be > careful that > the amount of movablemem_map areas are not too > large. > Otherwise kernel won't have enough memory to > start. > + NOTE: We don't stop users specifying the node > the > + kernel resides in as hotpluggable so that > this > + option can be used as a workaround of > firmware > + bugs. I usually see workaround "for", not "of". And your whitespace is inconsistent on that last line. And I'm now kind of curious what such a workaround would accomplish, but I'm suspect it's obvious to people who wind up needing it. > MTD_Partition= [MTD] > Format: ,,, > diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c > index b8028b2..79836d0 100644 > --- a/arch/x86/mm/srat.c > +++ b/arch/x86/mm/srat.c > @@ -166,6 +166,9 @@ handle_movablemem(int node, u64 start, u64 end, > u32 hotpluggable) > * for other purposes, such as for kernel image. We cannot > prevent > * kernel from using these memory, so we need to exclude these > memory > * even if it is hotpluggable. > + * Furthermore, to ensure the kernel has enough memory to boot, > we make > + * all the memory on the node which the kernel resides in > + * un-hotpluggable. > */ Can you hot-unplug half a node? (Do you have a choice with the granularity here?) Rob