[RFC PATCH 8/9] ARM64: mm: Introduce MAX_ZONE_ORDER for 64K and THP.
Catalin Marinas
catalin.marinas at arm.com
Thu May 2 06:00:00 EDT 2013
On Tue, Apr 30, 2013 at 05:30:47PM +0100, Steve Capper wrote:
> The buddy allocator has a default order of 11, which is too low to
> allocate enough memory for 512MB Transparent HugePages if our base
> page size is 64K. For any order less than 13, the combination of
> THP with 64K pages will cause a compile error.
>
> This patch introduces the MAX_ZONE_ORDER config option that allows
> one to explicitly override the order of the buddy allocator. If
> 64K pages and THP are enabled the minimum value is set to 13.
>
> Signed-off-by: Steve Capper <steve.capper at linaro.org>
> ---
> arch/arm64/Kconfig | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 16aa780..908fd95 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -196,6 +196,23 @@ config ARCH_WANT_HUGE_PMD_SHARE
>
> source "mm/Kconfig"
>
> +config FORCE_MAX_ZONEORDER
> + int "Maximum zone order"
> + range 11 64 if !(ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
> + range 13 64 if ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE
> + default "11" if !(ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
> + default "13" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
Can we just keep some sane defaults here without giving too much choice
to the user? Something like:
config FORCE_MAX_ZONEORDER
int
default "13" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
default "11"
We can extend it later if people need this but I'm aiming for a single
config on a multitude of boards.
--
Catalin
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