diff --git a/mm/khugepaged.c b/mm/khugepaged.c index e328a5ea9a56..719f49d1fba2 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1414,6 +1414,7 @@ out: static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) { struct vm_area_struct *vma; + struct mm_struct *mm; unsigned long addr; pmd_t *pmd, _pmd; @@ -1442,7 +1443,8 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) continue; if (vma->vm_end < addr + HPAGE_PMD_SIZE) continue; - pmd = mm_find_pmd(vma->vm_mm, addr); + mm = vma->vm_mm; + pmd = mm_find_pmd(mm, addr); if (!pmd) continue; /* @@ -1452,17 +1454,19 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) * mmap_sem while holding page lock. Fault path does it in * reverse order. Trylock is a way to avoid deadlock. */ - if (down_write_trylock(&vma->vm_mm->mmap_sem)) { - spinlock_t *ptl = pmd_lock(vma->vm_mm, pmd); - /* assume page table is clear */ - _pmd = pmdp_collapse_flush(vma, addr, pmd); - spin_unlock(ptl); - up_write(&vma->vm_mm->mmap_sem); - mm_dec_nr_ptes(vma->vm_mm); - pte_free(vma->vm_mm, pmd_pgtable(_pmd)); + if (down_write_trylock(&mm->mmap_sem)) { + if (!khugepaged_test_exit(mm)) { + spinlock_t *ptl = pmd_lock(mm, pmd); + /* assume page table is clear */ + _pmd = pmdp_collapse_flush(vma, addr, pmd); + spin_unlock(ptl); + mm_dec_nr_ptes(mm); + pte_free(mm, pmd_pgtable(_pmd)); + } + up_write(&mm->mmap_sem); } else { /* Try again later */ - khugepaged_add_pte_mapped_thp(vma->vm_mm, addr); + khugepaged_add_pte_mapped_thp(mm, addr); } } i_mmap_unlock_write(mapping);