x86: add tizen_qemu_x86_defconfig & tizen_qemu_x86_64_defconfig

[platform/kernel/linux-rpi.git] / mm / khugepaged.c

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index fd25d12..3afcb14 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1458,14 +1458,6 @@ 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)
@@ -1537,6 +1529,10 @@ 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);
@@ -1546,6 +1542,8 @@ 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: