[PATCH] powerpc/pseries: Perform full re-add of CPU for topology update post-migration

[Michael Ellerman]

Michael Bringmann <mwb at linux.vnet.ibm.com> writes:

> On 10/29/18 1:43 PM, Nathan Fontenot wrote:
>> On pseries systems, performing a partition migration can result in
>> altering the nodes a CPU is assigned to on the destination system. For
>> exampl, pre-migration on the source system CPUs are in node 1 and 3,
>> post-migration on the destination system CPUs are in nodes 2 and 3.
>> 
>> Handling the node change for a CPU can cause corruption in the slab
>> cache if we hit a timing where a CPUs node is changed while cache_reap()
>> is invoked. The corruption occurs because the slab cache code appears
>> to rely on the CPU and slab cache pages being on the same node.
>> 
>> The current dynamic updating of a CPUs node done in arch/powerpc/mm/numa.c
>> does not prevent us from hitting this scenario.
>> 
>> Changing the device tree property update notification handler that
>> recognizes an affinity change for a CPU to do a full DLPAR remove and
>> add of the CPU instead of dynamically changing its node resolves this
>> issue.
>> 
>> Signed-off-by: Nathan Fontenot <nfont at linux.vnet.ibm.com
> Signed-off-by: Michael W. Bringmann <mwb at linux.vnet.ibm.com>

Are you sure that's what you meant? ie. you wrote some of the patch?

What I'd like is to get a Tested-by from you.

cheers