diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c2b59db..116bab1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5745,9 +5745,10 @@
 	if (!numentries) {
 		/* round applicable memory size up to nearest megabyte */
 		numentries = nr_kernel_pages;
-		numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
-		numentries >>= 20 - PAGE_SHIFT;
-		numentries <<= 20 - PAGE_SHIFT;
+
+		/* It isn't necessary when PAGE_SIZE >= 1MB */
+		if (PAGE_SHIFT < 20)
+			numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
 
 		/* limit to 1 bucket per 2^scale bytes of low memory */
 		if (scale > PAGE_SHIFT)