Re: [PATCH v5 04/11] mm: thp: introduce CONFIG_ARCH_ENABLE_THP_MIGRATION

[Anshuman Khandual]

On 04/21/2017 02:17 AM, Zi Yan wrote:
> From: Naoya Horiguchi 
> 
> Introduces CONFIG_ARCH_ENABLE_THP_MIGRATION to limit thp migration
> functionality to x86_64, which should be safer at the first step.
> 
> Signed-off-by: Naoya Horiguchi 

Aneesh's latest HugeTLB migration enablement on powerpc should
make this work on powerpc platform as well. Will test it out
in some time but for now enabling only on x86 where you have
tested the series makes sense.

Reviewed-by: Anshuman Khandual 

[PATCH v5 04/11] mm: thp: introduce CONFIG_ARCH_ENABLE_THP_MIGRATION

[Zi Yan]

From: Naoya Horiguchi 

Introduces CONFIG_ARCH_ENABLE_THP_MIGRATION to limit thp migration
functionality to x86_64, which should be safer at the first step.

Signed-off-by: Naoya Horiguchi 
---
v1 -> v2:
- fixed config name in subject and patch description
---
 arch/x86/Kconfig|  4 
 include/linux/huge_mm.h | 10 ++
 mm/Kconfig  |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 69188841717a..97d094c67110 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2276,6 +2276,10 @@ config ARCH_ENABLE_HUGEPAGE_MIGRATION
def_bool y
depends on X86_64 && HUGETLB_PAGE && MIGRATION
 
+config ARCH_ENABLE_THP_MIGRATION
+   def_bool y
+   depends on X86_64 && TRANSPARENT_HUGEPAGE
+
 menu "Power management and ACPI options"
 
 config ARCH_HIBERNATION_HEADER
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a3762d49ba39..1b81cb57ff0f 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -212,6 +212,11 @@ void mm_put_huge_zero_page(struct mm_struct *mm);
 
 #define mk_huge_pmd(page, prot) pmd_mkhuge(mk_pmd(page, prot))
 
+static inline bool thp_migration_supported(void)
+{
+   return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION);
+}
+
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
 #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
@@ -306,6 +311,11 @@ static inline struct page *follow_devmap_pud(struct 
vm_area_struct *vma,
 {
return NULL;
 }
+
+static inline bool thp_migration_supported(void)
+{
+   return false;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #endif /* _LINUX_HUGE_MM_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index 9b8fccb969dc..317a2f973720 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -289,6 +289,9 @@ config MIGRATION
 config ARCH_ENABLE_HUGEPAGE_MIGRATION
bool
 
+config ARCH_ENABLE_THP_MIGRATION
+   bool
+
 config PHYS_ADDR_T_64BIT
def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
 
-- 
2.11.0