--- old/src/cpu/x86/vm/globals_x86.hpp	Wed Sep 21 11:38:16 2011
+++ new/src/cpu/x86/vm/globals_x86.hpp	Wed Sep 21 11:38:16 2011
@@ -70,7 +70,11 @@
 define_pd_global(bool, RewriteBytecodes,     true);
 define_pd_global(bool, RewriteFrequentPairs, true);
 
+#ifdef _ALLBSD_SOURCE
+define_pd_global(bool, UseMembar,            true);
+#else
 define_pd_global(bool, UseMembar,            false);
+#endif
 
 // GC Ergo Flags
 define_pd_global(intx, CMSYoungGenPerWorker, 64*M);  // default max size of CMS young gen, per GC worker thread