Re: [RFC PATCH v3 0/2] arm64/hugetlb: enable gigantic page

[Will Deacon]

On Mon, Aug 22, 2016 at 09:20:02PM +0800, Xie Yisheng wrote:
> Arm64 supports different size of gigantic page which can be seen from:
> commit 084bd29810a5 ("ARM64: mm: HugeTLB support.")
> commit 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")
> 
> So I tried to use this function by adding hugepagesz=1G in kernel
> parameters, with CONFIG_CMA=y. However, when I
> echo xx > \
>   /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
> it failed with the following info:
> -bash: echo: write error: Invalid argument
> 
> This is a v3 patchset which make gigantic page can be
> allocated and freed at runtime for arch arm64,
> with CONFIG_CMA=y or other related configs is enabled.
> 
> You can see the former discussions at:
> https://lkml.org/lkml/2016/8/18/310
> https://lkml.org/lkml/2016/8/21/410
>  
> Xie Yisheng (2):
>   mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE
>   arm64 Kconfig: Select gigantic page
> 
>  arch/arm64/Kconfig | 1 +
>  arch/s390/Kconfig  | 1 +
>  arch/x86/Kconfig   | 1 +
>  fs/Kconfig         | 3 ++++
>  mm/hugetlb.c       | 2 +-
>  5 files changed, 7 insertions(+), 1 deletion(-)

I assume you plan to merge this via -mm/akpm, given that Catalin has
acked the arm64 part?

Will