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

[David Hildenbrand]

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@xxxxxxxx
> >
> >
> > 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