From 7da4d641c58d201c3cc1835c05ca1a7fa26f0856 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 19 Nov 2012 03:14:23 +0100 Subject: [PATCH] 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 --- include/linux/hugetlb.h | 8 ++++-- include/linux/mm.h | 3 +++ mm/hugetlb.c | 10 +++++-- mm/mprotect.c | 58 +++++++++++++++++++++++++++++++---------- 4 files changed, 61 insertions(+), 18 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 225164842ab6..06e691baab86 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -87,7 +87,7 @@ struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address, pud_t *pud, int write); int pmd_huge(pmd_t pmd); int pud_huge(pud_t pmd); -void hugetlb_change_protection(struct vm_area_struct *vma, +unsigned long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot); #else /* !CONFIG_HUGETLB_PAGE */ @@ -132,7 +132,11 @@ static inline void copy_huge_page(struct page *dst, struct page *src) { } -#define hugetlb_change_protection(vma, address, end, newprot) +static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma, + unsigned long address, unsigned long end, pgprot_t newprot) +{ + return 0; +} static inline void __unmap_hugepage_range_final(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, diff --git a/include/linux/mm.h b/include/linux/mm.h index bcaab4e6fe91..1856c62d82cd 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1078,6 +1078,9 @@ extern unsigned long move_page_tables(struct vm_area_struct *vma, extern unsigned long do_mremap(unsigned long addr, unsigned long old_len, unsigned long new_len, unsigned long flags, unsigned long new_addr); +extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, + unsigned long end, pgprot_t newprot, + int dirty_accountable); extern int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 59a0059b39e2..712895eda0d0 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3014,7 +3014,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, return i ? i : -EFAULT; } -void hugetlb_change_protection(struct vm_area_struct *vma, +unsigned long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) { struct mm_struct *mm = vma->vm_mm; @@ -3022,6 +3022,7 @@ void hugetlb_change_protection(struct vm_area_struct *vma, pte_t *ptep; pte_t pte; struct hstate *h = hstate_vma(vma); + unsigned long pages = 0; BUG_ON(address >= end); flush_cache_range(vma, address, end); @@ -3032,12 +3033,15 @@ void hugetlb_change_protection(struct vm_area_struct *vma, ptep = huge_pte_offset(mm, address); if (!ptep) continue; - if (huge_pmd_unshare(mm, &address, ptep)) + if (huge_pmd_unshare(mm, &address, ptep)) { + pages++; continue; + } if (!huge_pte_none(huge_ptep_get(ptep))) { pte = huge_ptep_get_and_clear(mm, address, ptep); pte = pte_mkhuge(pte_modify(pte, newprot)); set_huge_pte_at(mm, address, ptep, pte); + pages++; } } spin_unlock(&mm->page_table_lock); @@ -3049,6 +3053,8 @@ void hugetlb_change_protection(struct vm_area_struct *vma, */ flush_tlb_range(vma, start, end); mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + + return pages << h->order; } int hugetlb_reserve_pages(struct inode *inode, 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 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, 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);