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

From: Will Deacon
Date: Sat Jan 19 2019 - 18:58:15 EST


On Thu, Jan 17, 2019 at 06:39:53PM +0000, Alexandre Ghiti wrote:
> From: Alexandre Ghiti <alex@xxxxxxxx>
>
> On systems without CMA or (MEMORY_ISOLATION && COMPACTION) activated but
> that support gigantic pages, boottime reserved gigantic pages can not be
> freed at all. This patchs simply enables the possibility to hand back
> those pages to memory allocator.
>
> This commit then renames gigantic_page_supported and
> ARCH_HAS_GIGANTIC_PAGE to make them more accurate. Indeed, those values
> being false does not mean that the system cannot use gigantic pages: it
> just means that runtime allocation of gigantic pages is not supported,
> one can still allocate boottime gigantic pages if the architecture supports
> it.
>
> Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
> ---
>
> - Compiled on all architectures
> - Tested on riscv architecture
>
> arch/arm64/Kconfig | 2 +-
> arch/arm64/include/asm/hugetlb.h | 7 +++--

The arm64 bits look straightforward enough to me...

Acked-by: Will Deacon <will.deacon@xxxxxxx>

Will