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

On Thu, Jan 17, 2019 at 06:39:53PM +0000, Alexandre Ghiti wrote:

From: Alexandre Ghiti <alex@ghiti.fr>

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@ghiti.fr>
---

- 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 <redacted>

Will