Re: [RFC PATCH 1/8] arm64/hugetlb: Extend batching of multiple CONT_PTE in a single PTE setup

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

On 08/04/26 8:21 am, Barry Song (Xiaomi) wrote:
> For sizes aligned to CONT_PTE_SIZE and smaller than PMD_SIZE,
> we can batch CONT_PTE settings instead of handling them individually.
> 
> Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
> ---
>  arch/arm64/mm/hugetlbpage.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index a42c05cf5640..bf31c11ebd3b 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -110,6 +110,12 @@ static inline int num_contig_ptes(unsigned long size, size_t *pgsize)
>  		contig_ptes = CONT_PTES;
>  		break;
>  	default:
> +		if (size < CONT_PMD_SIZE && size > 0 &&
> +				IS_ALIGNED(size, CONT_PTE_SIZE)) {

Nit: Having the lower bound check before upper bound is natural to
read, so this should be size > 0 && size < CONT_PMD_SIZE (i.e written
the other way around).

Also IS_ALIGNED needs to go below size.


> +			contig_ptes = size >> PAGE_SHIFT;
> +			*pgsize = PAGE_SIZE;
> +			break;
> +		}
>  		WARN_ON(!__hugetlb_valid_size(size));
>  	}
>  
> @@ -359,6 +365,10 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
>  	case CONT_PTE_SIZE:
>  		return pte_mkcont(entry);
>  	default:
> +		if (pagesize < CONT_PMD_SIZE && pagesize > 0 &&
> +				IS_ALIGNED(pagesize, CONT_PTE_SIZE))
> +			return pte_mkcont(entry);
> +
>  		break;
>  	}
>  	pr_warn("%s: unrecognized huge page size 0x%lx\n",