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-rw-r--r--mm/swapfile.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 36af6eeaa67e..6cf2e60983b7 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -866,6 +866,21 @@ unsigned int count_swap_pages(int type, int free)
866} 866}
867#endif /* CONFIG_HIBERNATION */ 867#endif /* CONFIG_HIBERNATION */
868 868
869static inline int maybe_same_pte(pte_t pte, pte_t swp_pte)
870{
871#ifdef CONFIG_MEM_SOFT_DIRTY
872 /*
873 * When pte keeps soft dirty bit the pte generated
874 * from swap entry does not has it, still it's same
875 * pte from logical point of view.
876 */
877 pte_t swp_pte_dirty = pte_swp_mksoft_dirty(swp_pte);
878 return pte_same(pte, swp_pte) || pte_same(pte, swp_pte_dirty);
879#else
880 return pte_same(pte, swp_pte);
881#endif
882}
883
869/* 884/*
870 * No need to decide whether this PTE shares the swap entry with others, 885 * No need to decide whether this PTE shares the swap entry with others,
871 * just let do_wp_page work it out if a write is requested later - to 886 * just let do_wp_page work it out if a write is requested later - to
@@ -892,7 +907,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
892 } 907 }
893 908
894 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 909 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
895 if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { 910 if (unlikely(!maybe_same_pte(*pte, swp_entry_to_pte(entry)))) {
896 mem_cgroup_cancel_charge_swapin(memcg); 911 mem_cgroup_cancel_charge_swapin(memcg);
897 ret = 0; 912 ret = 0;
898 goto out; 913 goto out;
@@ -947,7 +962,7 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
947 * swapoff spends a _lot_ of time in this loop! 962 * swapoff spends a _lot_ of time in this loop!
948 * Test inline before going to call unuse_pte. 963 * Test inline before going to call unuse_pte.
949 */ 964 */
950 if (unlikely(pte_same(*pte, swp_pte))) { 965 if (unlikely(maybe_same_pte(*pte, swp_pte))) {
951 pte_unmap(pte); 966 pte_unmap(pte);
952 ret = unuse_pte(vma, pmd, addr, entry, page); 967 ret = unuse_pte(vma, pmd, addr, entry, page);
953 if (ret) 968 if (ret)