diff options
Diffstat (limited to 'mm/internal.h')
| -rw-r--r-- | mm/internal.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/internal.h b/mm/internal.h index 18af980bb1b8..450a2c8a43f3 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -413,8 +413,15 @@ void mlock_page(struct page *page); static inline void mlock_vma_page(struct page *page, struct vm_area_struct *vma, bool compound) { - /* VM_IO check prevents migration from double-counting during mlock */ - if (unlikely((vma->vm_flags & (VM_LOCKED|VM_IO)) == VM_LOCKED) && + /* + * The VM_SPECIAL check here serves two purposes. + * 1) VM_IO check prevents migration from double-counting during mlock. + * 2) Although mmap_region() and mlock_fixup() take care that VM_LOCKED + * is never left set on a VM_SPECIAL vma, there is an interval while + * file->f_op->mmap() is using vm_insert_page(s), when VM_LOCKED may + * still be set while VM_SPECIAL bits are added: so ignore it then. + */ + if (unlikely((vma->vm_flags & (VM_LOCKED|VM_SPECIAL)) == VM_LOCKED) && (compound || !PageTransCompound(page))) mlock_page(page); } |