Re: [RFC PATCH v3 4/4] mm,memory_hotplug: Add mhp_memmap_on_memory boot option

[Oscar Salvador <osalvador@suse.de>]

On Wed, Dec 02, 2020 at 10:42:18AM +0100, David Hildenbrand wrote:
> I have another memhp tunable in the works. I suggest doing it like
> page_shuffling and using, module parameters instead. Makes this
> a bit nicer IMHO.

Does that have any impact?

> diff --git a/mm/Makefile b/mm/Makefile
> index 069f216e109e..ba7714b5eaa1 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -58,9 +58,13 @@ obj-y                        := filemap.o mempool.o oom_kill.o fadvise.o \
>  page-alloc-y := page_alloc.o
>  page-alloc-$(CONFIG_SHUFFLE_PAGE_ALLOCATOR) += shuffle.o
>  
> +# Give "memory_hotplug" its own module-parameter namespace
> +memory-hotplug-$(CONFIG_MEMORY_HOTPLUG) := memory_hotplug.o
> +
>  obj-y += page-alloc.o
>  obj-y += init-mm.o
>  obj-y += memblock.o
> +obj-y += $(memory-hotplug-y)
>  
>  ifdef CONFIG_MMU
>         obj-$(CONFIG_ADVISE_SYSCALLS)   += madvise.o
> @@ -82,7 +86,6 @@ obj-$(CONFIG_SLAB) += slab.o
>  obj-$(CONFIG_SLUB) += slub.o
>  obj-$(CONFIG_KASAN)    += kasan/
>  obj-$(CONFIG_FAILSLAB) += failslab.o
> -obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
>  obj-$(CONFIG_MEMTEST)          += memtest.o
>  obj-$(CONFIG_MIGRATION) += migrate.o
>  obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
> 
> 
> The you can just use module_param/MODULE_PARM_DESC and set the parameter via
> 
> "memory_hotplug.memmap_on_memory"

I have to confess that I was not aware of this trick, but looks cleaner
overall.

Thanks

-- 
Oscar Salvador
SUSE L3