# Re: \[RFC v2 4/4\] powerpc/papr\_scm: Add cpu hotplug support for nvdimm pmu device

- From: Aneesh Kumar K.V \<hidden\>
- Date: 2021-05-26 08:46:04 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/05/1392309
- Thread: https://ratatoskr.run/linuxppc-dev/2021/05/1391326/t.md

```text
On 5/26/21 12:56 PM, kajoljain wrote:
>
>
> On 5/25/21 7:46 PM, Peter Zijlstra wrote:
>> On Tue, May 25, 2021 at 06:52:16PM +0530, Kajol Jain wrote:
>>> Patch here adds cpu hotplug functions to nvdimm pmu.
>>
>> I'm thinking "Patch here" qualifies for "This patch", see
>> Documentation/process/submitting-patches.rst .
>>
> Hi Peter,
>     I will reword this commit message.
>
>>> It adds cpumask to designate a cpu to make HCALL to
>>> collect the counter data for the nvdimm device and
>>> update ABI documentation accordingly.
>>>
>>> Result in power9 lpar system:
>>> command:# cat /sys/devices/nmem0/cpumask
>>> 0
>>
>> Is this specific to the papr thing, or should this be in generic nvdimm
>> code?
>
> This code is not specific to papr device and we can move it to
> generic nvdimm interface. But do we need to add some checks on whether
> any arch/platform specific driver want that support or we can assume
> that this will be something needed by all platforms?
>

It says the cpu that should be used to make the hcall. That makes it PAPR specific.

-aneesh

```