[PATCH] Allow migration of mlocked pages

Hugh clarified the role of VM_LOCKED.  So we can now implement page
migration for mlocked pages.

Allow the migration of mlocked pages.  This means that try_to_unmap must
unmap mlocked pages in the migration case.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/migrate.c b/mm/migrate.c
index 0576c05..3f1e0c2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -616,15 +616,13 @@
 	/*
 	 * Establish migration ptes or remove ptes
 	 */
-	if (try_to_unmap(page, 1) != SWAP_FAIL) {
-		if (!page_mapped(page))
-			rc = move_to_new_page(newpage, page);
-	} else
-		/* A vma has VM_LOCKED set -> permanent failure */
-		rc = -EPERM;
+	try_to_unmap(page, 1);
+	if (!page_mapped(page))
+		rc = move_to_new_page(newpage, page);
 
 	if (rc)
 		remove_migration_ptes(page, page);
+
 unlock:
 	unlock_page(page);