On Sat, May 04, 2013 at 12:19:03AM +0530, Aneesh Kumar K.V wrote: > David Gibson <dwg@xxxxxxxxxxx> writes: > > > 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). > > done > > + /* > + * We support THP only if PMD_SIZE is 16MB. > + */ > + if (mmu_psize_defs[MMU_PAGE_16M].shift != PMD_SHIFT) > + return 0; > + /* Much better. > >> + /* > >> + * 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. > > > That is 64K linux page size and 4K HPTE . We do support that. Good point, sorry. -- 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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