Re: [PATCH 2/3] mm: Add generic helper to hint a large folio

[David Hildenbrand <david@redhat.com>]

On 09.05.25 07:25, Dev Jain wrote:
> 
> 
> On 08/05/25 4:25 pm, David Hildenbrand wrote:
>>
>>>> (2) Do we really need "must be part of the same folio", or could be just
>>>> batch over present
>>>> ptes that map consecutive PFNs? In that case, a helper that avoids
>>>> folio_pte_batch() completely
>>>> might be better.
>>>>
>>> I am not sure I get you here. folio_pte_batch() seems to be the simplest
>>> thing we can do as being done around in the code elsewhere, I am not
>>> aware of any alternate.
>>
>> If we don't need the folio, then we can have a batching function that
>> doesn't require the folio.
>>
>> Likely, we could even factor that (non-folio batching) out from
>> folio_pte_batch().
>> The recent fix [1] might make that easier. See below.
>>
>>
>> So my question is: is something relying on all of these PTEs to point at
>> the same folio?
> 
> Hmm...get_and_clear_full_ptes, as you say in another mail, will require
> that...
> 
>>
>> [1] https://lkml.kernel.org/r/20250502215019.822-2-arkamar@atlas.cz
>>
>>
>> Something like this: (would need kerneldoc, probably remove "addr"
>> parameter from folio_pte_batch(),
>> and look into other related cleanups as discussed with Andrew)
> 
> I like this refactoring! Can you tell the commit hash on which you make
> the patch, I cannot apply it.

Oh, it was just on top of my private version of [1]. It should now be in 
mm-new (or mm-unstable, did not check).

But as raised in my other mail, get_and_clear_full_ptes() might be 
problematic across folios.


-- 
Cheers,

David / dhildenb