diff options
| -rw-r--r-- | mm/khugepaged.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8e67d2e5ff39..f1f98305433e 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1328,14 +1328,6 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE)) return; - /* - * Symmetry with retract_page_tables(): Exclude MAP_PRIVATE mappings - * that got written to. Without this, we'd have to also lock the - * anon_vma if one exists. - */ - if (vma->anon_vma) - return; - hpage = find_lock_page(vma->vm_file->f_mapping, linear_page_index(vma, haddr)); if (!hpage) @@ -1407,6 +1399,10 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) } /* step 4: collapse pmd */ + /* we make no change to anon, but protect concurrent anon page lookup */ + if (vma->anon_vma) + anon_vma_lock_write(vma->anon_vma); + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm, haddr, haddr + HPAGE_PMD_SIZE); mmu_notifier_invalidate_range_start(&range); @@ -1416,6 +1412,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) mmu_notifier_invalidate_range_end(&range); pte_free(mm, pmd_pgtable(_pmd)); + if (vma->anon_vma) + anon_vma_unlock_write(vma->anon_vma); i_mmap_unlock_write(vma->vm_file->f_mapping); drop_hpage: |