Re: [PATCH v2] hugetlb: allow to free gigantic pages regardless of the configuration

[Dave Hansen]

> -#if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
> +#ifdef CONFIG_COMPACTION_CORE
>  static __init int gigantic_pages_init(void)
>  {
>  	/* With compaction or CMA we can allocate gigantic pages at runtime */
> diff --git a/fs/Kconfig b/fs/Kconfig
> index ac474a61be37..8fecd3ea5563 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -207,8 +207,9 @@ config HUGETLB_PAGE
>  config MEMFD_CREATE
>  	def_bool TMPFS || HUGETLBFS
>  
> -config ARCH_HAS_GIGANTIC_PAGE
> +config COMPACTION_CORE
>  	bool
> +	default y if (MEMORY_ISOLATION && MIGRATION) || CMA

This takes a hard dependency (#if) and turns it into a Kconfig *default*
that can be overridden.  That seems like trouble.

Shouldn't it be:

config COMPACTION_CORE
	def_bool y
	depends on (MEMORY_ISOLATION && MIGRATION) || CMA

?