Re: [RFC v2 4/4] powerpc/papr_scm: Add cpu hotplug support for nvdimm pmu device

From: Aneesh Kumar K.V
Date: Wed May 26 2021 - 04:46:06 EST


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