Re: [PATCH 04/16] libnvdimm: Move nd_numa_attribute_group to device_type

Aneesh Kumar K.V
2019-11-13T06:03:57Z

On 11/13/19 6:56 AM, Dan Williams wrote:
> On Tue, Nov 12, 2019 at 1:23 AM Aneesh Kumar K.V
> <aneesh.kumar@linux.ibm.com> wrote:
>>
>> Dan Williams <dan.j.williams@intel.com> writes:
>>
>>> A 'struct device_type' instance can carry default attributes for the
>>> device. Use this facility to remove the export of
>>> nd_numa_attribute_group and put the responsibility on the core rather
>>> than leaf implementations to define this attribute.
>>>
>>> Cc: Ira Weiny <ira.weiny@intel.com>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> Cc: "Oliver O'Halloran" <oohall@gmail.com>
>>> Cc: Vishal Verma <vishal.l.verma@intel.com>
>>> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>>
>>
>> can we also expose target_node in a similar way? This allows application
>> to better understand the node locality of the SCM device.
>
> It is already exported for device-dax instances. See
> DEVICE_ATTR_RO(target_node) in drivers/dax/bus.c. I did not see a use
> case for it to be exported for other nvdimm device types.
>

some applications do want to access the fsdax namspace as different
mount points based on numa affinity. If can differentiate the two
regions with different target_node and same numa_node, that will help
them better isolate these mounts.

-aneesh