diff --git a/mm/migrate.c b/mm/migrate.c
index 6602941..385db89 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -841,12 +841,12 @@
 	struct page_to_node *pp;
 	LIST_HEAD(pagelist);
 
+	migrate_prep();
 	down_read(&mm->mmap_sem);
 
 	/*
 	 * Build a list of pages to migrate
 	 */
-	migrate_prep();
 	for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
 		struct vm_area_struct *vma;
 		struct page *page;