Re: [RFC PATCH v2 12/12] mm: make MAX_ORDER a kernel boot time parameter.

[Randy Dunlap]

Hi--

On 8/11/22 16:16, Zi Yan wrote:
> diff --git a/mm/Kconfig b/mm/Kconfig
> index e558f5679707..acccb919d72d 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -455,6 +455,19 @@ config SET_MAX_ORDER
>  	  increase this value. A value of 10 means that the largest free memory
>  	  block is 2^10 pages.
>  
> +config BOOT_TIME_MAX_ORDER
> +	bool "Set maximum order of buddy allocator at boot time"
> +	depends on SPARSEMEM_VMEMMAP && (ARCH_FORCE_MAX_ORDER != 0 || SET_MAX_ORDER != 0)
> +	help
> +	  It enables users to set the maximum order of buddy allocator at system
> +      boot time instead of a static MACRO set at compilation time. Systems with
> +      a lot of memory might want to allocate large pages whereas it is much
> +      less feasible and desirable for systems with less memory. This option
> +      allows different systems to control the largest page they want to
> +      allocate. By default, MAX_ORDER will be set to ARCH_FORCE_MAX_ORDER or
> +      SET_MAX_ORDER, whichever is non-zero, when the boot time parameter is not
> +      set. The maximum of MAX_ORDER is currently limited at 256.

Please make sure that all lines of help text are indented with one tab + 2 spaces,
as specified in Documentation/process/coding-style.rst.

Thanks.
-- 
~Randy