Re: [PATCH] documentation/mm: Update pmd_present() in arch_pgtable_helpers.rst

[David Hildenbrand]

On 23.11.22 06:13, Anshuman Khandual wrote:
> Although pmd_present() might seem to indicate a valid and mapped pmd entry,
> in reality it returns true when pmd_page() points to a valid page in memory
> , regardless whether the pmd entry is mapped or not. Andrea Arcangeli had
> earlier explained [1] the required semantics for pmd_present(). This just
> updates the documentation for pmd_present() as required.
>
> [1] https://lore.kernel.org/lkml/20181017020930.GN30832@xxxxxxxxxx/
>
> Cc: Jonathan Corbet <corbet@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-doc@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> This applies on v6.1-rc6
>
> The latest trigger was from an earlier discussion here.
>
> https://lore.kernel.org/all/53c0c955-7afe-905b-468a-cd7ac81238c5@xxxxxxx/
>
>   Documentation/mm/arch_pgtable_helpers.rst | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst
> index cbaee9e59241..fd2a19df884e 100644
> --- a/Documentation/mm/arch_pgtable_helpers.rst
> +++ b/Documentation/mm/arch_pgtable_helpers.rst
> @@ -94,7 +94,7 @@ PMD Page Table Helpers
>   +---------------------------+--------------------------------------------------+
>   | pmd_trans_huge            | Tests a Transparent Huge Page (THP) at PMD       |
>   +---------------------------+--------------------------------------------------+
> -| pmd_present               | Tests a valid mapped PMD                         |
> +| pmd_present               | Tests whether pmd_page() points to valid memory  |
>   +---------------------------+--------------------------------------------------+
>   | pmd_young                 | Tests a young PMD                                |
>   +---------------------------+--------------------------------------------------+

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Thanks,

David / dhildenb