The patch titled
Subject: mm/mglru: add CONFIG_ARCH_HAS_HW_PTE_YOUNG
has been added to the -mm mm-unstable branch. Its filename is
mm-mglru-add-config_arch_has_hw_pte_young.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-add-config_arch_has_hw_pte_young.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kinsey Ho <kinseyho@xxxxxxxxxx>
Subject: mm/mglru: add CONFIG_ARCH_HAS_HW_PTE_YOUNG
Date: Wed, 27 Dec 2023 14:12:01 +0000
Patch series "mm/mglru: Kconfig cleanup", v4.
This series is the result of the following discussion:
https://lore.kernel.org/47066176-bd93-55dd-c2fa-002299d9e034@xxxxxxxxxxxxx/
It mainly avoids building the code that walks page tables on CPUs that
use it, i.e., those don't support hardware accessed bit. Specifically,
it introduces a new Kconfig to guard some of functions added by
commit bd74fdaea146 ("mm: multi-gen LRU: support page table walks")
on CPUs like POWER9, on which the series was tested.
This patch (of 5):
Some architectures are able to set the accessed bit in PTEs when PTEs
are used as part of linear address translations.
Add CONFIG_ARCH_HAS_HW_PTE_YOUNG for such architectures to be able to
override arch_has_hw_pte_young().
Link: https://lkml.kernel.org/r/20231227141205.2200125-1-kinseyho@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20231227141205.2200125-2-kinseyho@xxxxxxxxxx
Signed-off-by: Kinsey Ho <kinseyho@xxxxxxxxxx>
Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Tested-by: Donet Tom <donettom@xxxxxxxxxxxxxxxxxx>
Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/Kconfig | 8 ++++++++
arch/arm64/Kconfig | 1 +
arch/x86/Kconfig | 1 +
arch/x86/include/asm/pgtable.h | 6 ------
include/linux/pgtable.h | 2 +-
5 files changed, 11 insertions(+), 7 deletions(-)
--- a/arch/arm64/Kconfig~mm-mglru-add-config_arch_has_hw_pte_young
+++ a/arch/arm64/Kconfig
@@ -36,6 +36,7 @@ config ARM64
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_DEVMAP
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_HW_PTE_YOUNG
select ARCH_HAS_SETUP_DMA_OPS
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
--- a/arch/Kconfig~mm-mglru-add-config_arch_has_hw_pte_young
+++ a/arch/Kconfig
@@ -1470,6 +1470,14 @@ config DYNAMIC_SIGFRAME
config HAVE_ARCH_NODE_DEV_GROUP
bool
+config ARCH_HAS_HW_PTE_YOUNG
+ bool
+ help
+ Architectures that select this option are capable of setting the
+ accessed bit in PTE entries when using them as part of linear address
+ translations. Architectures that require runtime check should select
+ this option and override arch_has_hw_pte_young().
+
config ARCH_HAS_NONLEAF_PMD_YOUNG
bool
help
--- a/arch/x86/include/asm/pgtable.h~mm-mglru-add-config_arch_has_hw_pte_young
+++ a/arch/x86/include/asm/pgtable.h
@@ -1679,12 +1679,6 @@ static inline bool arch_has_pfn_modify_c
return boot_cpu_has_bug(X86_BUG_L1TF);
}
-#define arch_has_hw_pte_young arch_has_hw_pte_young
-static inline bool arch_has_hw_pte_young(void)
-{
- return true;
-}
-
#define arch_check_zapped_pte arch_check_zapped_pte
void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte);
--- a/arch/x86/Kconfig~mm-mglru-add-config_arch_has_hw_pte_young
+++ a/arch/x86/Kconfig
@@ -88,6 +88,7 @@ config X86
select ARCH_HAS_PMEM_API if X86_64
select ARCH_HAS_PTE_DEVMAP if X86_64
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_HW_PTE_YOUNG
select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
select ARCH_HAS_COPY_MC if X86_64
--- a/include/linux/pgtable.h~mm-mglru-add-config_arch_has_hw_pte_young
+++ a/include/linux/pgtable.h
@@ -375,7 +375,7 @@ static inline bool arch_has_hw_nonleaf_p
*/
static inline bool arch_has_hw_pte_young(void)
{
- return false;
+ return IS_ENABLED(CONFIG_ARCH_HAS_HW_PTE_YOUNG);
}
#endif
_
Patches currently in -mm which might be from kinseyho@xxxxxxxxxx are
mm-mglru-add-config_arch_has_hw_pte_young.patch
mm-mglru-add-config_lru_gen_walks_mmu.patch
mm-mglru-remove-config_memcg.patch
mm-mglru-add-dummy-pmd_dirty.patch
mm-mglru-remove-config_transparent_hugepage.patch
