From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
We enable only if the we support 16MB page size.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/pgtable-ppc64.h | 3 +--
arch/powerpc/mm/pgtable_64.c | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h
b/arch/powerpc/include/asm/pgtable-ppc64.h
index 97fc839..d65534b 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -426,8 +426,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
return pmd_val(pmd) >> PTE_RPN_SHIFT;
}
-/* We will enable it in the last patch */
-#define has_transparent_hugepage() 0
+extern int has_transparent_hugepage(void);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
static inline int pmd_young(pmd_t pmd)
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 54216c1..b742d6f 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -754,6 +754,34 @@ void update_mmu_cache_pmd(struct vm_area_struct *vma,
unsigned long addr,
return;
}
+int has_transparent_hugepage(void)
+{
+ if (!mmu_has_feature(MMU_FTR_16M_PAGE))
+ return 0;
+ /*
+ * We support THP only if HPAGE_SHIFT is 16MB.
+ */
+ if (!HPAGE_SHIFT || (HPAGE_SHIFT != mmu_psize_defs[MMU_PAGE_16M].shift))
+ return 0;
+ /*
+ * We need to make sure that we support 16MB hugepage in a segement
+ * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE
+ * of 64K.
+ */
+ /*
+ * If we have 64K HPTE, we will be using that by default
+ */
+ if (mmu_psize_defs[MMU_PAGE_64K].shift &&
+ (mmu_psize_defs[MMU_PAGE_64K].penc[MMU_PAGE_16M] == -1))
+ return 0;
+ /*
+ * Ok we only have 4K HPTE
+ */
+ if (mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M] == -1)
+ return 0;
+
+ return 1;
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
pmd_t pmdp_get_and_clear(struct mm_struct *mm,
--
1.8.1.2
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