From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f180.google.com (mail-qc0-f180.google.com [209.85.216.180]) by kanga.kvack.org (Postfix) with ESMTP id 0D8236B0036 for ; Wed, 21 May 2014 10:16:33 -0400 (EDT) Received: by mail-qc0-f180.google.com with SMTP id i17so3276709qcy.39 for ; Wed, 21 May 2014 07:16:32 -0700 (PDT) Received: from qmta14.emeryville.ca.mail.comcast.net (qmta14.emeryville.ca.mail.comcast.net. [2001:558:fe2d:44:76:96:27:212]) by mx.google.com with ESMTP id g62si1397361qgf.39.2014.05.21.07.16.30 for ; Wed, 21 May 2014 07:16:30 -0700 (PDT) Date: Wed, 21 May 2014 09:16:27 -0500 (CDT) From: Christoph Lameter Subject: Re: Node 0 not necessary for powerpc? In-Reply-To: <20140519182400.GM8941@linux.vnet.ibm.com> Message-ID: References: <20140311195632.GA946@linux.vnet.ibm.com> <20140313164949.GC22247@linux.vnet.ibm.com> <20140519182400.GM8941@linux.vnet.ibm.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Nishanth Aravamudan Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, anton@samba.org, David Rientjes , benh@kernel.crashing.org, Tejun Heo , tony.luck@intel.com On Mon, 19 May 2014, Nishanth Aravamudan wrote: > I'm seeing a panic at boot with this change on an LPAR which actually > has no Node 0. Here's what I think is happening: > > start_kernel > ... > -> setup_per_cpu_areas > -> pcpu_embed_first_chunk > -> pcpu_fc_alloc > -> ___alloc_bootmem_node(NODE_DATA(cpu_to_node(cpu), ... > -> smp_prepare_boot_cpu > -> set_numa_node(boot_cpuid) > > So we panic on the NODE_DATA call. It seems that ia64, at least, uses > pcpu_alloc_first_chunk rather than embed. x86 has some code to handle > early calls of cpu_to_node (early_cpu_to_node) and sets the mapping for > all CPUs in setup_per_cpu_areas(). Maybe we can switch ia64 too embed? Tejun: Why are there these dependencies? > Thoughts? Does that mean we need something similar to x86 for powerpc? Tejun is the expert in this area. CCing him. -- 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/ . Don't email: email@kvack.org