Re: RESEND Re: [Patch 2/2]: powerpc/hotplug/mm: Fix hot-add memory node assoc

[Balbir Singh]

On Wed, Jun 14, 2017 at 3:25 PM, Balbir Singh <bsingharora@xxxxxxxxx> wrote:
>
>
> On Wed, Jun 14, 2017 at 8:21 AM, Michael Bringmann <mwb@xxxxxxxxxxxxxxxxxx>
> wrote:
>>
>> On a related note, we are discussing the addition of 2 new device-tree
>> properties
>> with Pete Heyrman and his fellows that should simplify the determination
>> of the
>> set of required nodes.
>>
>> * One property would provide the total/max number of nodes needed by the
>> kernel
>>   on the current hardware.
>
>

Yes, that would be nice to have

>
>>
>> * A second property would provide the total/max number of nodes that the
>> kernel
>>   could use on any system to which it could be migrated.
>>
>

Not sure about this one, are you suggesting more memory can be added
depending on the migration target?

>
>
>>
>> These properties aren't available, yet, and it takes time to define new
>> properties
>> in the PAPR and have them implemented in pHyp and the kernel.  As an
>> intermediary
>> step, the systems which are doing a lot of dynamic hot-add/hot-remove
>> configuration
>> could provide equivalent information to the PowerPC kernel with a command
>> line
>> parameter.  The 'numa.c' code would then read this value and fill in the
>> necessary
>> entries in the 'node_possible_map'.
>>
>> Would you foresee any problems with using such a feature?
>
>

Sorry my mailer goofed up, resending

Balbir Singh