[RFC PATCH -V2 21/21] powerpc/THP: Enable THP on PPC64
From: Aneesh Kumar K.V <hidden>
Date: 2013-02-21 16:48:07
Also in:
linux-mm
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: "Aneesh Kumar K.V" <redacted> We enable only if the we support 16MB page size. Signed-off-by: Aneesh Kumar K.V <redacted> --- arch/powerpc/include/asm/pgtable.h | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 5b8e93b..ae9114b 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h@@ -107,8 +107,37 @@ static inline int pmd_trans_huge(pmd_t pmd) return ((pmd_val(pmd) & PMD_ISHUGE) == PMD_ISHUGE); } -/* We will enable it in the last patch */ -#define has_transparent_hugepage() 0 +static inline 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 huge page in a segement + * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE + * of 64K. + */ + /* FIXME!! is the nonzero check always correct ? Can there be an machine + * where penc is 0 ? + */ + /* + * 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]) + return 0; + /* + * Ok we only have 4K HPTE + */ + if (!mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M]) + return 0; + + return 1; +} static inline pmd_t pmd_mkold(pmd_t pmd) {
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1.7.10