Re: [PATCH v8 4/4] hugetlb: allow to free gigantic pages regardless of the configuration

[Aneesh Kumar K.V]

On 3/27/19 12:06 PM, Alexandre Ghiti wrote:
> On systems without CONTIG_ALLOC activated but that support gigantic pages,
> boottime reserved gigantic pages can not be freed at all. This patch
> simply enables the possibility to hand back those pages to memory
> allocator.
>
> Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
> Acked-by: David S. Miller <davem@xxxxxxxxxxxxx> [sparc]
>
> diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h
> index ec2a55a553c7..7013284f0f1b 100644
> --- a/arch/powerpc/include/asm/book3s/64/hugetlb.h
> +++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h
> @@ -36,8 +36,8 @@ static inline int hstate_get_psize(struct hstate *hstate)
>   	}
>   }
>   
> -#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
> -static inline bool gigantic_page_supported(void)
> +#define __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED
> +static inline bool gigantic_page_runtime_supported(void)
>   {
>   	/*
>   	 * We used gigantic page reservation with hypervisor assist in some case.
> @@ -49,7 +49,6 @@ static inline bool gigantic_page_supported(void)
>   
>   	return true;
>   }
> -#endif
>   
>   /* hugepd entry valid bit */
>   #define HUGEPD_VAL_BITS		(0x8000000000000000UL)

Is that correct when CONTIG_ALLOC is not enabled? I guess we want

gigantic_page_runtime_supported to return false when CONTIG_ALLOC is not 
enabled on all architectures and on POWER when it is enabled we want it 
to be conditional as it is now.

-aneesh