[PATCH v7 16/20] huge_memory: Add vmf_insert_folio_pmd()
David Hildenbrand
david at redhat.com
Tue Feb 11 05:45:09 AEDT 2025
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 at 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
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