--- a/hotspot/src/share/vm/runtime/globals.hpp	Thu Jan 29 21:25:42 2009 -0800
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Fri Jan 30 14:17:52 2009 -0800
@@ -1426,10 +1426,10 @@
   develop(bool, CMSOverflowEarlyRestoration, false,                         \
           "Whether preserved marks should be restored early")               \
                                                                             \
-  product(uintx, CMSMarkStackSize, 32*K,                                    \
+  product(uintx, CMSMarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M),           \
           "Size of CMS marking stack")                                      \
                                                                             \
-  product(uintx, CMSMarkStackSizeMax, 4*M,                                  \
+  product(uintx, CMSMarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M),       \
           "Max size of CMS marking stack")                                  \
                                                                             \
   notproduct(bool, CMSMarkStackOverflowALot, false,                         \