From: Michael Bringmann <mwb@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nathan Fontenot <nfont@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Cc: ldufour@linux.vnet.ibm.com
Subject: Re: [PATCH] powerpc/pseries: Perform full re-add of CPU for topology update post-migration
Date: Tue, 29 Jan 2019 10:12:36 -0600 [thread overview]
Message-ID: <719fbfbf-795b-05c8-c181-96dd9c63b448@linux.vnet.ibm.com> (raw)
In-Reply-To: <877eenst1l.fsf@concordia.ellerman.id.au>
On 1/29/19 3:37 AM, Michael Ellerman wrote:
> Michael Bringmann <mwb@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@linux.vnet.ibm.com
>> Signed-off-by: Michael W. Bringmann <mwb@linux.vnet.ibm.com>
Tested-by: Michael W. Bringmann <mwb@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
>
>
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
mwb@linux.vnet.ibm.com
next prev parent reply other threads:[~2019-01-29 16:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-29 18:43 [PATCH] powerpc/pseries: Perform full re-add of CPU for topology update post-migration Nathan Fontenot
2019-01-28 15:41 ` Michael Bringmann
2019-01-29 9:37 ` Michael Ellerman
2019-01-29 16:12 ` Michael Bringmann [this message]
2019-01-30 12:28 ` Michael Ellerman
2019-02-08 13:02 ` Michael Ellerman
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