--- old/src/share/vm/gc_implementation/g1/concurrentMark.cpp	2013-07-31 14:32:58.638954092 +0200
+++ new/src/share/vm/gc_implementation/g1/concurrentMark.cpp	2013-07-31 14:32:58.394954096 +0200
@@ -410,9 +410,8 @@
 }
 
 ConcurrentMark::ConcurrentMark(ReservedSpace rs, uint max_regions) :
-  _markBitMap1(rs, MinObjAlignment - 1),
-  _markBitMap2(rs, MinObjAlignment - 1),
-
+  _markBitMap1(rs, log2_intptr(MinObjAlignment)),
+  _markBitMap2(rs, log2_intptr(MinObjAlignment)),
   _parallel_marking_threads(0),
   _max_parallel_marking_threads(0),
   _sleep_factor(0.0),