diff -r 455328d90876 -r abdfc822206f src/share/vm/memory/cardTableModRefBS.hpp
--- a/src/share/vm/memory/cardTableModRefBS.hpp	Tue Mar 29 22:36:16 2011 -0400
+++ b/src/share/vm/memory/cardTableModRefBS.hpp	Wed Mar 30 10:26:59 2011 -0400
@@ -382,6 +382,11 @@
     return (addr_for(pcard) == p);
   }
 
+  HeapWord* align_to_card_boundary(HeapWord* p) {
+    jbyte* pcard = byte_for(p + card_size_in_words - 1);
+    return addr_for(pcard);
+  }
+
   // The kinds of precision a CardTableModRefBS may offer.
   enum PrecisionStyle {
     Precise,