Re: [PATCH v5 02/18] mm: Define __pte_leaf_size() to also take a PMD entry

Peter Xu
2024-06-11T15:20:15Z

On Tue, Jun 11, 2024 at 05:08:45PM +0200, Oscar Salvador wrote:
> The problem is that we do not have spare bits for 8xx to mark these ptes
> as cont-ptes or mark them pte as 8MB, so I do not see a clear path on how
> we could remove huge_ptep_get for 8xx.

Right, I remember I thought about this too when I initially looked at one
previous version of the series, I didn't come up yet with a good solution,
but I guess we probably need to get rid of hugepd first anyway. We may
somehow still need to identify this is a 8M large leaf, and I guess this is
again the only special case where contpte can go over >1 pmds.

>
> I am really curious though how we handle that for THP? Or THP on 8xx
> does not support that size?

I'll leave this to Christophe, but IIUC thp is only PMD_ORDER sized, so
shouldn't apply to the 8MB pages.

Thanks,

--
Peter Xu