Re: [PATCH v3 2/8] mm/mprotect: Remove NUMA_HUGE_PTE_UPDATES

David Hildenbrand
2024-08-06T13:02:06Z

> Right.
>
> I don't have a reason to change numa_pte_updates semantics yet so far, but
> here there's the problem where numa_huge_pte_updates can be ambiguous when
> there is even PUD involved.
>
> In general, I don't know how I should treat this counter in PUD path even
> if NUMA isn't involved in dax yet; it can be soon involved if we move on
> with using this same path for hugetlb, or when 1G thp can be possible (with
> Yu Zhao's TAO?).

We shouldn't bother about it in the PUD path at all I think. Especially
as long as NUMA hinting doesn't apply to any of what we would handle on
the PUD path :)

>
> One other thing I can do is I drop this patch, ignore NUMA_HUGE_PTE_UPDATES
> in PUD dax processing for now. It'll work for this series, but it'll still
> be a problem later. I figured maybe we should simply drop it from now.

It probably shouldn't block your other fixes and we should likely
discuss that separately.

I agree that we should look into dropping that PMD counter completely.

--
Cheers,

David / dhildenb