diff --git a/mm/swap.c b/mm/swap.c
index 4a8a59e..308e57d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -496,7 +496,7 @@
  */
 void __init swap_setup(void)
 {
-	unsigned long megs = num_physpages >> (20 - PAGE_SHIFT);
+	unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
 
 #ifdef CONFIG_SWAP
 	bdi_init(swapper_space.backing_dev_info);