[PATCH v3 7/8] powerpc/mm: Consolidate radix and hash address map details

[Aneesh Kumar K.V]

On 4/16/19 7:33 PM, Nicholas Piggin wrote:
> Aneesh Kumar K.V's on April 16, 2019 8:07 pm:
>> We now have
>>
>> 4K page size config
>>
>>   kernel_region_map_size = 16TB
>>   kernel vmalloc start   = 0xc000100000000000
>>   kernel IO start        = 0xc000200000000000
>>   kernel vmemmap start   = 0xc000300000000000
>>
>> with 64K page size config:
>>
>>   kernel_region_map_size = 512TB
>>   kernel vmalloc start   = 0xc008000000000000
>>   kernel IO start        = 0xc00a000000000000
>>   kernel vmemmap start   = 0xc00c000000000000
> 
> Hey Aneesh,
> 
> I like the series, I like consolidating the address spaces into 0xc,
> and making the layouts match or similar isn't a bad thing. I don't
> see any real reason to force limitations on one layout or another --
> you could make the argument that 4k radix should match 64k radix
> as much as matching 4k hash IMO.
> 
> I wouldn't like to tie them too strongly to the same base defines
> that force them to stay in sync.
> 
> Can we drop this patch? Or at least keep the users of the H_ and R_
> defines and set them to the same thing in map.h?
> 
> 

I did that based on the suggestion from Michael Ellerman. I guess he 
wanted the VMALLOC_START to match. I am not sure whether we should match 
the kernel_region_map_size too. I did mention that in the cover letter.

I agree with your suggestion above. I still can keep the VMALLOC_START 
at 16TB and keep the region_map_size as 512TB for radix 4k. I am not 
sure we want to do that.

I will wait for feedback from Michael to make the suggested changes.

-aneesh