[PATCH] x86/mm: Enable 5-level paging support by default

From: Kirill A. Shutemov
Date: Fri Sep 13 2019 - 05:55:14 EST


Support of boot-time switching between 4- and 5-level paging mode is
upstream since 4.17.

We run internal testing with 5-level paging support enabled for a while
and it doesn't not cause any functional or performance regression on
4-level paging hardware.

The only 5-level paging related regressions I saw were in early boot
code that runs independently from CONFIG_X86_5LEVEL.

The next major release of distributions expected to have
CONFIG_X86_5LEVEL=y.

Enable the option by default. It may help to catch obscure bugs early.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/Kconfig | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 222855cc0158..2f7cb91d850e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1483,6 +1483,7 @@ config X86_PAE

config X86_5LEVEL
bool "Enable 5-level page tables support"
+ default y
select DYNAMIC_MEMORY_LAYOUT
select SPARSEMEM_VMEMMAP
depends on X86_64
--
2.21.0