From 7aa9a23c69eae5bfba4f1f92c58d89edc334c8ae Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 15 Jan 2016 16:53:21 -0800 Subject: [PATCH] powerpc, thp: remove infrastructure for handling splitting PMDs With new refcounting we don't need to mark PMDs splitting. Let's drop code to handle this. pmdp_splitting_flush() is not needed too: on splitting PMD we will do pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as needed for fast_gup. Signed-off-by: Kirill A. Shutemov Tested-by: Aneesh Kumar K.V Reviewed-by: Aneesh Kumar K.V Cc: Sasha Levin Cc: Jerome Marchand Cc: Vlastimil Babka Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Naoya Horiguchi Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/include/asm/book3s/64/hash-64k.h | 12 ----- arch/powerpc/include/asm/book3s/64/hash.h | 10 +--- arch/powerpc/include/asm/book3s/64/pgtable.h | 4 -- arch/powerpc/mm/hugepage-hash64.c | 3 -- arch/powerpc/mm/hugetlbpage.c | 4 -- arch/powerpc/mm/pgtable_64.c | 49 ------------------- 6 files changed, 2 insertions(+), 80 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h index 9e55e3b1fef0..849bbec80f7b 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h @@ -256,13 +256,6 @@ static inline int pmd_trans_huge(pmd_t pmd) (_PAGE_PTE | _PAGE_THP_HUGE)); } -static inline int pmd_trans_splitting(pmd_t pmd) -{ - if (pmd_trans_huge(pmd)) - return pmd_val(pmd) & _PAGE_SPLITTING; - return 0; -} - static inline int pmd_large(pmd_t pmd) { return !!(pmd_val(pmd) & _PAGE_PTE); @@ -273,11 +266,6 @@ static inline pmd_t pmd_mknotpresent(pmd_t pmd) return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT); } -static inline pmd_t pmd_mksplitting(pmd_t pmd) -{ - return __pmd(pmd_val(pmd) | _PAGE_SPLITTING); -} - #define __HAVE_ARCH_PMD_SAME static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) { diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index 2ff8b3df553d..06f17e778c27 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -40,11 +40,6 @@ #define _PAGE_SOFT_DIRTY 0x00000 #endif -/* - * THP pages can't be special. So use the _PAGE_SPECIAL - */ -#define _PAGE_SPLITTING _PAGE_SPECIAL - /* * We need to differentiate between explicit huge page and THP huge * page, since THP huge page also need to track real subpage details @@ -54,9 +49,8 @@ /* * set of bits not changed in pmd_modify. */ -#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | \ - _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_SPLITTING | \ - _PAGE_THP_HUGE | _PAGE_PTE | _PAGE_SOFT_DIRTY) +#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \ + _PAGE_ACCESSED | _PAGE_THP_HUGE) #ifdef CONFIG_PPC_64K_PAGES #include diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index b3a5badab69f..da11c4ac8a09 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -266,10 +266,6 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma, extern pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp); -#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH -extern void pmdp_splitting_flush(struct vm_area_struct *vma, - unsigned long address, pmd_t *pmdp); - extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); #define pmdp_collapse_flush pmdp_collapse_flush diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c index baf1301ded0c..49b152b0f926 100644 --- a/arch/powerpc/mm/hugepage-hash64.c +++ b/arch/powerpc/mm/hugepage-hash64.c @@ -39,9 +39,6 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, /* If PMD busy, retry the access */ if (unlikely(old_pmd & _PAGE_BUSY)) return 0; - /* If PMD is trans splitting retry the access */ - if (unlikely(old_pmd & _PAGE_SPLITTING)) - return 0; /* If PMD permissions don't match, take page fault */ if (unlikely(access & ~old_pmd)) return 1; diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 6bd3afa775d3..744e24bcb85c 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -958,10 +958,6 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, /* * A hugepage collapse is captured by pmd_none, because * it mark the pmd none and do a hpte invalidate. - * - * We don't worry about pmd_trans_splitting here, The - * caller if it needs to handle the splitting case - * should check for that. */ if (pmd_none(pmd)) return NULL; diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index ea6bc31debb0..3124a20d0fab 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -603,55 +603,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma, return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp); } -/* - * We mark the pmd splitting and invalidate all the hpte - * entries for this hugepage. - */ -void pmdp_splitting_flush(struct vm_area_struct *vma, - unsigned long address, pmd_t *pmdp) -{ - unsigned long old, tmp; - - VM_BUG_ON(address & ~HPAGE_PMD_MASK); - -#ifdef CONFIG_DEBUG_VM - WARN_ON(!pmd_trans_huge(*pmdp)); - assert_spin_locked(&vma->vm_mm->page_table_lock); -#endif - -#ifdef PTE_ATOMIC_UPDATES - - __asm__ __volatile__( - "1: ldarx %0,0,%3\n\ - andi. %1,%0,%6\n\ - bne- 1b \n\ - oris %1,%0,%4@h \n\ - stdcx. %1,0,%3 \n\ - bne- 1b" - : "=&r" (old), "=&r" (tmp), "=m" (*pmdp) - : "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY) - : "cc" ); -#else - old = pmd_val(*pmdp); - *pmdp = __pmd(old | _PAGE_SPLITTING); -#endif - /* - * If we didn't had the splitting flag set, go and flush the - * HPTE entries. - */ - trace_hugepage_splitting(address, old); - if (!(old & _PAGE_SPLITTING)) { - /* We need to flush the hpte */ - if (old & _PAGE_HASHPTE) - hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old); - } - /* - * This ensures that generic code that rely on IRQ disabling - * to prevent a parallel THP split work as expected. - */ - kick_all_cpus_sync(); -} - /* * We want to put the pgtable in pmd and use pgtable for tracking * the base page size hptes -- 2.20.1