[PATCH V2] mm/thp: Make ARCH_ENABLE_SPLIT_PMD_PTLOCK dependent on PGTABLE_LEVELS > 2

[Anshuman Khandual]

ARCH_ENABLE_SPLIT_PMD_PTLOCK is irrelevant unless there are more than two
page table levels including PMD (also per
Documentation/vm/split_page_table_lock.rst). Make this dependency explicit
on remaining platforms i.e x86 and s390 where ARCH_ENABLE_SPLIT_PMD_PTLOCK
is subscribed.

Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Acked-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx> # s390
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
Changes in V2:

- Updated the commit message per Gerald

Changes in V1:

https://lore.kernel.org/linux-mm/1620621345-29176-1-git-send-email-anshuman.khandual@xxxxxxx/

 arch/s390/Kconfig | 2 +-
 arch/x86/Kconfig  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b4c7c34069f8..fcc1ea339a9d 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -62,7 +62,7 @@ config S390
 	select ARCH_BINFMT_ELF_STATE
 	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
 	select ARCH_ENABLE_MEMORY_HOTREMOVE
-	select ARCH_ENABLE_SPLIT_PMD_PTLOCK
+	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
 	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select ARCH_HAS_DEBUG_WX
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0045e1b44190..ec9e9d3d7e3f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -63,7 +63,7 @@ config X86
 	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
 	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM)
 	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
-	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if X86_64 || X86_PAE
+	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
 	select ARCH_HAS_CACHE_LINE_SIZE
-- 
2.20.1