Re: [RFC PATCH v3 1/4] mm,memory_hotplug: Add mhp_supports_memmap_on_memory

[David Hildenbrand]

On 09.12.20 10:36, Oscar Salvador wrote:
> On Wed, Dec 02, 2020 at 10:36:54AM +0100, David Hildenbrand wrote:
>> Instead of adding these arch callbacks, what about a config option
>>
>> ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
>>
>> that gets selected by the archs with CONFIG_SPARSEMEM_VMEMMAP ?
>>
>> The mhp_supports_memmap_on_memory() becomes even more trivial.
> 
> I think that would not be enough.
> E.g: s390x supports CONFIG_SPARSEMEM_VMEMMAP but it does not support
> altmap (and maybe other arches I did not check too).
> That is why I was careful in choosing the ones that a) supports
> CONFIG_SPARSEMEM_VMEMMAP and b) support altmap

Sorry if I was unclear, s390x will simply not set
ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE.

-- 
Thanks,

David / dhildenb