Re: [PATCH v2 0/3] mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes

[Andrew Morton]

On Wed, 11 Jun 2025 14:06:51 +0200 David Hildenbrand <david@xxxxxxxxxx> wrote:

> While working on improving vm_normal_page() and friends, I stumbled
> over this issues: refcounted "normal" pages must not be marked
> using pmd_special() / pud_special().

Why is this?

>
> ...
>
> I spent too much time trying to get the ndctl tests mentioned by Dan
> running (.config tweaks, memmap= setup, ... ), without getting them to
> pass even without these patches. Some SKIP, some FAIL, some sometimes
> suddenly SKIP on first invocation, ... instructions unclear or the tests
> are shaky. This is how far I got:

I won't include this in the [0/N] - it doesn't seem helpful for future
readers of the patchset.

I'll give the patchset a run in mm-new, but it feels like some more
baking is needed?

The [1/N] has cc:stable but there's nothing in there to explain this
decision.  How does the issues affect userspace?