On Mon, Apr 29, 2013 at 01:21:49AM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> We enable only if the we support 16MB page size.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> ---
> 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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