Re: [PATCH -V7 08/10] powerpc/THP: Enable THP on PPC64
From: David Gibson <hidden>
Date: 2013-05-03 05:30:39
Also in:
linux-mm
On Mon, Apr 29, 2013 at 01:21:49AM +0530, Aneesh Kumar K.V wrote:
quoted hunk ↗ jump to hunk
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-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;
Again, THP should not be dependent on the value of HPAGE_SHIFT. Just checking that mmu_psize_defsz[MMU_PAGE_16M].shift == 24 should be sufficient (i.e. that 16M hugepages are supported).
+ /* + * 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;
Except you don't actually support THP on 4K base page size yet.
+ + return 1; +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ pmd_t pmdp_get_and_clear(struct mm_struct *mm,
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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