Re: [PATCH v4 2/6] arm64/vmalloc: Allow arch_vmap_pte_range_map_size to batch multiple CONT_PTE

[Dev Jain <dev.jain@arm.com>]

On 18/06/26 2:17 pm, Wen Jiang wrote:
> From: "Barry Song (Xiaomi)" <baohua@kernel.org>
> 
> Allow arch_vmap_pte_range_map_size to batch across multiple CONT_PTE
> blocks, reducing both PTE setup and TLB flush iterations.
> 
> Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
> Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
> ---
>  arch/arm64/include/asm/vmalloc.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
> index 4ec1acd3c1b34..787fd17b48e2c 100644
> --- a/arch/arm64/include/asm/vmalloc.h
> +++ b/arch/arm64/include/asm/vmalloc.h
> @@ -23,6 +23,8 @@ static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr,
>  						unsigned long end, u64 pfn,
>  						unsigned int max_page_shift)
>  {
> +	unsigned long size;
> +
>  	/*
>  	 * If the block is at least CONT_PTE_SIZE in size, and is naturally
>  	 * aligned in both virtual and physical space, then we can pte-map the
> @@ -40,7 +42,9 @@ static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr,
>  	if (!IS_ALIGNED(PFN_PHYS(pfn), CONT_PTE_SIZE))
>  		return PAGE_SIZE;
>  
> -	return CONT_PTE_SIZE;
> +	size = min3(end - addr, 1UL << max_page_shift, PMD_SIZE >> 1);
> +	size = 1UL << __fls(size);

Nit: I'd rather use rounddown_pow_of_two() : __fls is confusing : )

Reviewed-by: Dev Jain <dev.jain@arm.com>


> +	return size;
>  }
>  
>  #define arch_vmap_pte_range_unmap_size arch_vmap_pte_range_unmap_size