From 7da4d641c58d201c3cc1835c05ca1a7fa26f0856 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 19 Nov 2012 03:14:23 +0100 Subject: mm: Count the number of pages affected in change_protection() This will be used for three kinds of purposes: - to optimize mprotect() - to speed up working set scanning for working set areas that have not been touched - to more accurately scan per real working set No change in functionality from this patch. Suggested-by: Ingo Molnar Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Mel Gorman Cc: Hugh Dickins Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- mm/mprotect.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 44 insertions(+), 14 deletions(-) (limited to 'mm/mprotect.c') diff --git a/mm/mprotect.c b/mm/mprotect.c index a40992610ab6..1e265be25f85 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -35,12 +35,13 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) } #endif -static void change_pte_range(struct mm_struct *mm, pmd_t *pmd, +static unsigned long change_pte_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable) { pte_t *pte, oldpte; spinlock_t *ptl; + unsigned long pages = 0; pte = pte_offset_map_lock(mm, pmd, addr, &ptl); arch_enter_lazy_mmu_mode(); @@ -60,6 +61,7 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd, ptent = pte_mkwrite(ptent); ptep_modify_prot_commit(mm, addr, pte, ptent); + pages++; } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { swp_entry_t entry = pte_to_swp_entry(oldpte); @@ -72,18 +74,22 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd, set_pte_at(mm, addr, pte, swp_entry_to_pte(entry)); } + pages++; } } while (pte++, addr += PAGE_SIZE, addr != end); arch_leave_lazy_mmu_mode(); pte_unmap_unlock(pte - 1, ptl); + + return pages; } -static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud, +static inline unsigned long change_pmd_range(struct vm_area_struct *vma, pud_t *pud, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable) { pmd_t *pmd; unsigned long next; + unsigned long pages = 0; pmd = pmd_offset(pud, addr); do { @@ -91,35 +97,42 @@ static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud, if (pmd_trans_huge(*pmd)) { if (next - addr != HPAGE_PMD_SIZE) split_huge_page_pmd(vma->vm_mm, pmd); - else if (change_huge_pmd(vma, pmd, addr, newprot)) + else if (change_huge_pmd(vma, pmd, addr, newprot)) { + pages += HPAGE_PMD_NR; continue; + } /* fall through */ } if (pmd_none_or_clear_bad(pmd)) continue; - change_pte_range(vma->vm_mm, pmd, addr, next, newprot, + pages += change_pte_range(vma->vm_mm, pmd, addr, next, newprot, dirty_accountable); } while (pmd++, addr = next, addr != end); + + return pages; } -static inline void change_pud_range(struct vm_area_struct *vma, pgd_t *pgd, +static inline unsigned long change_pud_range(struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable) { pud_t *pud; unsigned long next; + unsigned long pages = 0; pud = pud_offset(pgd, addr); do { next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - change_pmd_range(vma, pud, addr, next, newprot, + pages += change_pmd_range(vma, pud, addr, next, newprot, dirty_accountable); } while (pud++, addr = next, addr != end); + + return pages; } -static void change_protection(struct vm_area_struct *vma, +static unsigned long change_protection_range(struct vm_area_struct *vma, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable) { @@ -127,6 +140,7 @@ static void change_protection(struct vm_area_struct *vma, pgd_t *pgd; unsigned long next; unsigned long start = addr; + unsigned long pages = 0; BUG_ON(addr >= end); pgd = pgd_offset(mm, addr); @@ -135,10 +149,30 @@ static void change_protection(struct vm_area_struct *vma, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - change_pud_range(vma, pgd, addr, next, newprot, + pages += change_pud_range(vma, pgd, addr, next, newprot, dirty_accountable); } while (pgd++, addr = next, addr != end); + flush_tlb_range(vma, start, end); + + return pages; +} + +unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, + unsigned long end, pgprot_t newprot, + int dirty_accountable) +{ + struct mm_struct *mm = vma->vm_mm; + unsigned long pages; + + mmu_notifier_invalidate_range_start(mm, start, end); + if (is_vm_hugetlb_page(vma)) + pages = hugetlb_change_protection(vma, start, end, newprot); + else + pages = change_protection_range(vma, start, end, newprot, dirty_accountable); + mmu_notifier_invalidate_range_end(mm, start, end); + + return pages; } int @@ -213,12 +247,8 @@ success: dirty_accountable = 1; } - mmu_notifier_invalidate_range_start(mm, start, end); - if (is_vm_hugetlb_page(vma)) - hugetlb_change_protection(vma, start, end, vma->vm_page_prot); - else - change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable); - mmu_notifier_invalidate_range_end(mm, start, end); + change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable); + vm_stat_account(mm, oldflags, vma->vm_file, -nrpages); vm_stat_account(mm, newflags, vma->vm_file, nrpages); perf_event_mmap(vma); -- cgit v1.2.3