Re: [RFC v2 0/3] Decoupling large folios dependency on THP

[David Hildenbrand (Arm)]

On 2/27/26 21:16, Zi Yan wrote:
> On 27 Feb 2026, at 15:10, David Hildenbrand (Arm) wrote:
> 
>> On 2/27/26 16:19, Matthew Wilcox wrote:
>>>
>>> In the Ottawa interpretation, that's true, but I'd prefer not to revisit
>>> this code when transitioning to the New York interpretation.  This is
>>> the NOMMU code after all, and the less time we spend on it, the better.
>>>
>>>
>>> Depending on your point of view, either everything is mapped on nommu,
>>> or nothing is mapped ;-)  In any case, the folio is freshly-allocated
>>> and locked, so there's no chance anybody has mapped it yet.
>>>
>>>
>>> Well, it is, but it's also exactly what we need to do -- frees folios
>>> which are now entirely beyond i_size.  And it's code that's also used on
>>> MMU systems, and the more code that's shared, the better.
>>>
>>>
>>> Right, we could do that.  But that's more code and special code in the
>>> nommu codebase.
>>
>> I guess I'd have to see the frankenstein folio_split() to judge if it is
>> really better :)
>>
>> If it's really just about skipping the unmap+remap the end result would
>> indeed be nice.
> 
> Without unmap+remap, that is just __folio_freeze_and_split_unmapped()? ;)

I'm rather wondering what else we find when we try actually using it :)

-- 
Cheers,

David