Re: [PATCH v7 16/20] huge_memory: Add vmf_insert_folio_pmd()

[David Hildenbrand <david@redhat.com>]

On 04.02.25 23:48, Alistair Popple wrote:
> Currently DAX folio/page reference counts are managed differently to normal
> pages. To allow these to be managed the same as normal pages introduce
> vmf_insert_folio_pmd. This will map the entire PMD-sized folio and take
> references as it would for a normally mapped page.
> 
> This is distinct from the current mechanism, vmf_insert_pfn_pmd, which
> simply inserts a special devmap PMD entry into the page table without
> holding a reference to the page for the mapping.
> 
> It is not currently useful to implement a more generic vmf_insert_folio()
> which selects the correct behaviour based on folio_order(). This is because
> PTE faults require only a subpage of the folio to be PTE mapped rather than
> the entire folio. It would be possible to add this context somewhere but
> callers already need to handle PTE faults and PMD faults separately so a
> more generic function is not useful.
> 
> Signed-off-by: Alistair Popple <apopple@nvidia.com>

Nit: patch subject ;)

> 
> ---
> 
> Changes for v7:
> 
>   - Fix bad pgtable handling for PPC64 (Thanks Dan and Dave)

Is it? ;) insert_pfn_pmd() still doesn't consume a "pgtable_t *"

But maybe I am missing something ...

-- 
Cheers,

David / dhildenb