Re: [PATCH 03/14] mm/Kconfig: make CONFIG_MEMORY_HOTPLUG depend on CONFIG_SPARSEMEM_VMEMMAP

Mike Rapoport
2026-03-18T07:55:19Z

On Tue, Mar 17, 2026 at 05:56:41PM +0100, David Hildenbrand (Arm) wrote:
> Ever since commit f8f03eb5f0f9 ("mm: stop making SPARSEMEM_VMEMMAP
> user-selectable"), an architecture that supports CONFIG_SPARSEMEM_VMEMMAP
> (by selecting SPARSEMEM_VMEMMAP_ENABLE) can no longer enable
> CONFIG_SPARSEMEM without CONFIG_SPARSEMEM_VMEMMAP.
>
> Right now, CONFIG_MEMORY_HOTPLUG is guarded by CONFIG_SPARSEMEM.
>
> However, CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG is only enabled by
> * arm64: which selects SPARSEMEM_VMEMMAP_ENABLE
> * loongarch: which selects SPARSEMEM_VMEMMAP_ENABLE
> * powerpc (64bit): which selects SPARSEMEM_VMEMMAP_ENABLE
> * riscv (64bit): which selects SPARSEMEM_VMEMMAP_ENABLE
> * s390 with SPARSEMEM: which selects SPARSEMEM_VMEMMAP_ENABLE
> * x86 (64bit): which selects SPARSEMEM_VMEMMAP_ENABLE
>
> So, we can make CONFIG_MEMORY_HOTPLUG depend on CONFIG_SPARSEMEM_VMEMMAP
> without affecting any setups.
>
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
> mm/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index ebd8ea353687..c012944938a7 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -472,7 +472,7 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
> menuconfig MEMORY_HOTPLUG
> bool "Memory hotplug"
> select MEMORY_ISOLATION
> - depends on SPARSEMEM
> + depends on SPARSEMEM_VMEMMAP
> depends on ARCH_ENABLE_MEMORY_HOTPLUG
> depends on 64BIT
> select NUMA_KEEP_MEMINFO if NUMA
> --
> 2.43.0
>

--
Sincerely yours,
Mike.