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To: Nishanth Aravamudan <nacc@linux.vnet.ibm.com> 
From: Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [2/2] powerpc/numa: ensure per-cpu NUMA mappings are correct on
 topology update
Message-Id: <20141021043627.99A4F14008C@ozlabs.org>
Date: Tue, 21 Oct 2014 15:36:27 +1100 (AEDT)
Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@samba.org>,
 Michael Wang <wangyun@linux.vnet.ibm.com>, Li Zhong <zhong@linux.vnet.ibm.com>,
 jstancek@redhat.com
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On Sat, 2014-18-10 at 00:50:40 UTC, Nishanth Aravamudan wrote:
> We received a report of warning in kernel/sched/core.c where the sched
> group was NULL on an LPAR after a topology update. This seems to occur
> because after the topology update has moved the CPUs, cpu_to_node is
> returning the old value still, which ends up breaking the consistency of
> the NUMA topology in the per-cpu maps. Ensure that we update the per-cpu
> fields when we re-map CPUs.

This looks like a bug fix, I assume you want it to go in for 3.18 ?

cheers