[PATCH 2/2] powerpc/mm: Increase MAX_PHYSMEM_BITS to 128TB with SPARSEMEM_VMEMMAP config

[Aneesh Kumar K.V]

On 06/21/2018 05:02 PM, Balbir Singh wrote:
> On Thu, Jun 21, 2018 at 6:31 PM, Aneesh Kumar K.V
> <aneesh.kumar at linux.ibm.com> wrote:
>>
>> We do this only with VMEMMAP config so that our page_to_[nid/section] etc are not
>> impacted.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> 
> Why 128TB, given that it's sparse_vmemmap_extreme by default, why not
> 1PB directly (50 bits)?
> 

That will impact config with VMEMMAP_EXTREME disabled with no real 
immediate benefit. We could possibly make MAX_PHYSMEM_BITS a Kconfig 
variable. s390 do that. Not sure we want to do that.

-aneesh