Re: [PATCH 1/2] mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE

["Lorenzo Stoakes (Oracle)" <ljs@kernel.org>]

On Thu, Mar 19, 2026 at 09:19:40AM +0100, David Hildenbrand (Arm) wrote:
> All architectures that select CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE also
> select CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG. So we can just remove
> CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE.
>
> For CONFIG_MIGRATION, make it depend on CONFIG_MEMORY_HOTREMOVE instead,
> and make CONFIG_MEMORY_HOTREMOVE select CONFIG_MIGRATION (just like
> CONFIG_CMA and CONFIG_COMPACTION already do).

Makes sense!

>
> We'll clean up CONFIG_MIGRATION next.
>
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>

LGTM, so:

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

> ---
>  arch/arm64/Kconfig     | 1 -
>  arch/loongarch/Kconfig | 1 -
>  arch/powerpc/Kconfig   | 1 -
>  arch/riscv/Kconfig     | 1 -
>  arch/s390/Kconfig      | 1 -
>  arch/x86/Kconfig       | 1 -
>  mm/Kconfig             | 9 +++------
>  7 files changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 38dba5f7e4d2..bcd9f5bc66e2 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -16,7 +16,6 @@ config ARM64
>  	select ARCH_BINFMT_ELF_STATE
>  	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
>  	select ARCH_ENABLE_MEMORY_HOTPLUG
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE
>  	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>  	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
>  	select ARCH_HAS_CACHE_LINE_SIZE
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index d211c6572b0a..dbf65ad512f1 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -12,7 +12,6 @@ config LOONGARCH
>  	select ARCH_NEEDS_DEFER_KASAN
>  	select ARCH_DISABLE_KASAN_INLINE
>  	select ARCH_ENABLE_MEMORY_HOTPLUG
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE
>  	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
>  	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
>  	select ARCH_HAS_CPU_FINALIZE_INIT
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index ad7a2fe63a2a..9f3417b75b2b 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -126,7 +126,6 @@ config PPC
>  	select ARCH_DISABLE_KASAN_INLINE	if PPC_RADIX_MMU
>  	select ARCH_DMA_DEFAULT_COHERENT	if !NOT_COHERENT_CACHE
>  	select ARCH_ENABLE_MEMORY_HOTPLUG
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE
>  	select ARCH_HAS_COPY_MC			if PPC64
>  	select ARCH_HAS_CURRENT_STACK_POINTER
>  	select ARCH_HAS_DEBUG_VIRTUAL
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 90c531e6abf5..61a9d8d3ea64 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -21,7 +21,6 @@ config RISCV
>  	select ARCH_DMA_DEFAULT_COHERENT
>  	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
>  	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM_VMEMMAP
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
>  	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>  	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
>  	select ARCH_HAS_BINFMT_FLAT
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index edc927d9e85a..d01800962d84 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -85,7 +85,6 @@ config S390
>  	select ARCH_32BIT_USTAT_F_TINODE
>  	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
>  	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE
>  	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>  	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
>  	select ARCH_HAS_CC_CAN_LINK
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index e2df1b147184..c290fe363f27 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -69,7 +69,6 @@ config X86
>  	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
>  	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
>  	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
> -	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
>  	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
>  	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
>  	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
> diff --git a/mm/Kconfig b/mm/Kconfig
> index c012944938a7..b2e21d873d3f 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -465,9 +465,6 @@ config HAVE_BOOTMEM_INFO_NODE
>  config ARCH_ENABLE_MEMORY_HOTPLUG
>  	bool
>
> -config ARCH_ENABLE_MEMORY_HOTREMOVE
> -	bool
> -
>  # eventually, we can have this option just 'select SPARSEMEM'
>  menuconfig MEMORY_HOTPLUG
>  	bool "Memory hotplug"
> @@ -540,8 +537,8 @@ endchoice
>  config MEMORY_HOTREMOVE
>  	bool "Allow for memory hot remove"
>  	select HAVE_BOOTMEM_INFO_NODE if (X86_64 || PPC64)
> -	depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
> -	depends on MIGRATION
> +	depends on MEMORY_HOTPLUG
> +	select MIGRATION
>
>  config MHP_MEMMAP_ON_MEMORY
>  	def_bool y
> @@ -636,7 +633,7 @@ config PAGE_REPORTING
>  config MIGRATION
>  	bool "Page migration"
>  	default y
> -	depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
> +	depends on (NUMA || MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
>  	help
>  	  Allows the migration of the physical location of pages of processes
>  	  while the virtual addresses are not changed. This is useful in
>
> --
> 2.43.0
>