Re: [PATCH 03/13] mm: Add generic p?d_large() macros

[Mark Rutland]

On Fri, Feb 15, 2019 at 05:02:24PM +0000, Steven Price wrote:
> From: James Morse <james.morse@xxxxxxx>
>
> Exposing the pud/pgd levels of the page tables to walk_page_range() means
> we may come across the exotic large mappings that come with large areas
> of contiguous memory (such as the kernel's linear map).
>
> For architectures that don't provide p?d_large() macros, provided a
> does nothing default.
>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
> Signed-off-by: Steven Price <steven.price@xxxxxxx>
> ---
>  include/asm-generic/pgtable.h | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index 05e61e6c843f..7630d663cd51 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -1186,4 +1186,14 @@ static inline bool arch_has_pfn_modify_check(void)
>  #define mm_pmd_folded(mm)__is_defined(__PAGETABLE_PMD_FOLDED)
>  #endif
>
> +#ifndef pgd_large
> +#define pgd_large(x)0
> +#endif
> +#ifndef pud_large
> +#define pud_large(x)0
> +#endif
> +#ifndef pmd_large
> +#define pmd_large(x)0
> +#endif

It might be worth a comment defining the semantics of these, e.g. how
they differ from p?d_huge() and p?d_trans_huge().

Thanks,
Mark.

> +
>  #endif /* _ASM_GENERIC_PGTABLE_H */
> --
> 2.20.1
>
>
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