--- a/hotspot/src/share/vm/memory/genCollectedHeap.cpp	Mon May 03 17:23:58 2010 -0400
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.cpp	Mon May 03 20:19:05 2010 -0700
@@ -410,9 +410,9 @@
 }
 
 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
-  return (cause == GCCause::_java_lang_system_gc ||
-          cause == GCCause::_gc_locker) &&
-         UseConcMarkSweepGC && ExplicitGCInvokesConcurrent;
+  return UseConcMarkSweepGC &&
+         ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
+          (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
 }
 
 void GenCollectedHeap::do_collection(bool  full,