From 8fe627ec5b7c47b1654dff50536d9709863295a3 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Mon, 28 Apr 2008 02:13:28 -0700 Subject: [PATCH] hugetlbfs: add missing TLB flush to hugetlb_cow() A cow break on a hugetlbfs page with page_count > 1 will set a new pte with set_huge_pte_at(), w/o any tlb flush operation. The old pte will remain in the tlb and subsequent write access to the page will result in a page fault loop, for as long as it may take until the tlb is flushed from somewhere else. This patch introduces an architecture-specific huge_ptep_clear_flush() function, which is called before the the set_huge_pte_at() in hugetlb_cow(). ATTENTION: This is just a nop on all architectures for now, the s390 implementation will come with our large page patch later. Other architectures should define their own huge_ptep_clear_flush() if needed. Acked-by: Martin Schwidefsky Signed-off-by: Gerald Schaefer Cc: Paul Mundt Cc: "Luck, Tony" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-ia64/hugetlb.h | 5 +++++ include/asm-powerpc/hugetlb.h | 5 +++++ include/asm-sh/hugetlb.h | 5 +++++ include/asm-sparc64/hugetlb.h | 5 +++++ include/asm-x86/hugetlb.h | 5 +++++ mm/hugetlb.c | 1 + 6 files changed, 26 insertions(+) diff --git a/include/asm-ia64/hugetlb.h b/include/asm-ia64/hugetlb.h index f0ee14c6e1..5f54343749 100644 --- a/include/asm-ia64/hugetlb.h +++ b/include/asm-ia64/hugetlb.h @@ -34,4 +34,9 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, return ptep_get_and_clear(mm, addr, ptep); } +static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} + #endif /* _ASM_IA64_HUGETLB_H */ diff --git a/include/asm-powerpc/hugetlb.h b/include/asm-powerpc/hugetlb.h index f537993c5c..bead2ff784 100644 --- a/include/asm-powerpc/hugetlb.h +++ b/include/asm-powerpc/hugetlb.h @@ -34,4 +34,9 @@ static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm) { } +static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} + #endif /* _ASM_POWERPC_HUGETLB_H */ diff --git a/include/asm-sh/hugetlb.h b/include/asm-sh/hugetlb.h index 885218d2c8..d1ed476467 100644 --- a/include/asm-sh/hugetlb.h +++ b/include/asm-sh/hugetlb.h @@ -46,4 +46,9 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, return ptep_get_and_clear(mm, addr, ptep); } +static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} + #endif /* _ASM_SH_HUGETLB_H */ diff --git a/include/asm-sparc64/hugetlb.h b/include/asm-sparc64/hugetlb.h index 7e111cfd31..0b9e44c85c 100644 --- a/include/asm-sparc64/hugetlb.h +++ b/include/asm-sparc64/hugetlb.h @@ -39,4 +39,9 @@ static inline void hugetlb_free_pgd_range(struct mmu_gather **tlb, free_pgd_range(tlb, addr, end, floor, ceiling); } +static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} + #endif /* _ASM_SPARC64_HUGETLB_H */ diff --git a/include/asm-x86/hugetlb.h b/include/asm-x86/hugetlb.h index ec21cedd71..f57236dfc8 100644 --- a/include/asm-x86/hugetlb.h +++ b/include/asm-x86/hugetlb.h @@ -46,4 +46,9 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, return ptep_get_and_clear(mm, addr, ptep); } +static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} + #endif /* _ASM_X86_HUGETLB_H */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d36e1f11a5..262d0a93d2 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -892,6 +892,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, ptep = huge_pte_offset(mm, address & HPAGE_MASK); if (likely(pte_same(*ptep, pte))) { /* Break COW */ + huge_ptep_clear_flush(vma, address, ptep); set_huge_pte_at(mm, address, ptep, make_huge_pte(vma, new_page, 1)); /* Make the old page be freed below */ -- 2.39.5