From a1dd450bcb1a05e8218b9aac0ee36f8755d8a140 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 11 Dec 2012 16:01:27 -0800 Subject: mm: thp: set the accessed flag for old pages on access fault On x86 memory accesses to pages without the ACCESSED flag set result in the ACCESSED flag being set automatically. With the ARM architecture a page access fault is raised instead (and it will continue to be raised until the ACCESSED flag is set for the appropriate PTE/PMD). For normal memory pages, handle_pte_fault will call pte_mkyoung (effectively setting the ACCESSED flag). For transparent huge pages, pmd_mkyoung will only be called for a write fault. This patch ensures that faults on transparent hugepages which do not result in a CoW update the access flags for the faulting pmd. Signed-off-by: Will Deacon Cc: Chris Metcalf Acked-by: Kirill A. Shutemov Cc: Andrea Arcangeli Acked-by: Johannes Weiner Cc: Ni zhan Chen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ea5fb93..5f902e2 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -784,6 +784,28 @@ out: return ret; } +void huge_pmd_set_accessed(struct mm_struct *mm, + struct vm_area_struct *vma, + unsigned long address, + pmd_t *pmd, pmd_t orig_pmd, + int dirty) +{ + pmd_t entry; + unsigned long haddr; + + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(*pmd, orig_pmd))) + goto unlock; + + entry = pmd_mkyoung(orig_pmd); + haddr = address & HPAGE_PMD_MASK; + if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) + update_mmu_cache_pmd(vma, address, pmd); + +unlock: + spin_unlock(&mm->page_table_lock); +} + static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, -- cgit v1.1