--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Mon Jan 16 22:10:05 2012 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Wed Jan 18 10:30:12 2012 -0500
@@ -1886,6 +1886,10 @@
   // races with it goes around and waits for completeCleanup to finish.
   g1h->increment_total_collections();
 
+  // We reclaimed old regions so we should calculate the sizes to make
+  // sure we update the old gen/space data.
+  g1h->g1mm()->update_sizes();
+
   if (VerifyDuringGC) {
     HandleMark hm;  // handle scope
     gclog_or_tty->print(" VerifyDuringGC:(after)");