Subject: Re: [PATCH v4 8/9] mm/mremap: Allow arch runtime override

From: Michael Ellerman <[email-masked]>
Date: Tue, 20 Apr 2021 13:52:09 +1000

"Aneesh Kumar K.V" <[email-masked]> writes:
> Architectures like ppc64 support faster mremap only with radix
> translation. Hence allow a runtime check w.r.t support for fast mremap.
>
> Signed-off-by: Aneesh Kumar K.V <[email-masked]>
> ---
>  arch/powerpc/include/asm/tlb.h |  6 ++++++
>  mm/mremap.c                    | 15 ++++++++++++++-
>  2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
> index 160422a439aa..058918a7cd3c 100644
> --- a/arch/powerpc/include/asm/tlb.h
> +++ b/arch/powerpc/include/asm/tlb.h
> @@ -83,5 +83,11 @@ static inline int mm_is_thread_local(struct mm_struct *mm)
>  }
>  #endif
>  
> +#define arch_supports_page_tables_move arch_supports_page_tables_move
> +static inline bool arch_supports_page_tables_move(void)
> +{
> +	return radix_enabled();
> +}

Not sure it's worth a respin on its own, but page table*s* move is
slightly strange phrasing.

arch_supports_move_page_tables() or arch_supports_page_table_move()
would be more typical.

cheers