Re: [PATCH] arm64: hugetlb: Register hugepages during arch init

[Steve Capper <Steve.Capper@arm.com>]

On Tue, Oct 23, 2018 at 06:36:57AM +0530, Allen Pais wrote:
> Add hstate for each supported hugepage size using arch initcall.
> 
> * no hugepage parameters
> 
>   Without hugepage parameters, only a default hugepage size is
>   available for dynamic allocation.  It's different, for example, from
>   x86_64 and sparc64 where all supported hugepage sizes are available.
> 
> * only default_hugepagesz= is specified and set not to HPAGE_SIZE
> 
>   In spite of the fact that default_hugepagesz= is set to a valid
>   hugepage size, it's treated as unsupported and reverted to
>   HPAGE_SIZE.  Such behaviour is also different from x86_64 and
>   sparc64.
> 
> Reviewed-by: Tom Saeger <tom.saeger@oracle.com>
> Signed-off-by: Dmitry Klochkov <dmitry.klochkov@oracle.com>
> Signed-off-by: Allen Pais <allen.pais@oracle.com>
> ---
>  arch/arm64/mm/hugetlbpage.c | 33 ++++++++++++++++++++++-----------
>  1 file changed, 22 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index f58ea50..28cbc22 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -429,6 +429,27 @@ void huge_ptep_clear_flush(struct vm_area_struct *vma,
>  	clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
>  }
>  
> +static void __init add_huge_page_size(unsigned long size)
> +{
> +	if (size_to_hstate(size))
> +		return;
> +
> +	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
> +}
> +
> +static int __init hugetlbpage_init(void)
> +{
> +#ifdef CONFIG_ARM64_4K_PAGES
> +	add_huge_page_size(PUD_SIZE);
> +#endif
> +	add_huge_page_size(PMD_SIZE * CONT_PMDS);
> +	add_huge_page_size(PMD_SIZE);
> +	add_huge_page_size(PAGE_SIZE * CONT_PTES);
> +
> +	return 0;
> +}
> +arch_initcall(hugetlbpage_init);
> +
>  static __init int setup_hugepagesz(char *opt)
>  {
>  	unsigned long ps = memparse(opt, &opt);
> @@ -440,7 +461,7 @@ static __init int setup_hugepagesz(char *opt)
>  	case PMD_SIZE * CONT_PMDS:
>  	case PMD_SIZE:
>  	case PAGE_SIZE * CONT_PTES:
> -		hugetlb_add_hstate(ilog2(ps) - PAGE_SHIFT);
> +		add_huge_page_size(ps);
>  		return 1;
>  	}
>  
> @@ -449,13 +470,3 @@ static __init int setup_hugepagesz(char *opt)
>  	return 0;
>  }
>  __setup("hugepagesz=", setup_hugepagesz);
> -
> -#ifdef CONFIG_ARM64_64K_PAGES
> -static __init int add_default_hugepagesz(void)
> -{
> -	if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
> -		hugetlb_add_hstate(CONT_PTE_SHIFT);
> -	return 0;
> -}
> -arch_initcall(add_default_hugepagesz);
> -#endif
> -- 
> 1.8.3.1
> 


Apologies for missing this, I like the idea of having all the hugetlb
sizes accessible right away.

FWIW:
Acked-by: Steve Capper <steve.capper@arm.com>

Cheers,
-- 
Steve