--- a/hotspot/src/share/vm/runtime/arguments.cpp Wed Sep 19 08:48:10 2012 -0700
+++ b/hotspot/src/share/vm/runtime/arguments.cpp Wed Sep 19 15:48:02 2012 -0700
@@ -1978,6 +1978,19 @@
status = status && verify_min_value(ClassMetaspaceSize, 1*M,
"ClassMetaspaceSize");
+#ifdef SPARC
+ if (UseConcMarkSweepGC || UseG1GC) {
+ // Issue a stern warning if the user has explicitly set
+ // UseMemSetInBOT (it is known to cause issues), but allow
+ // use for experimentation and debugging.
+ if (VM_Version::is_sun4v() && UseMemSetInBOT) {
+ assert(!FLAG_IS_DEFAULT(UseMemSetInBOT), "Error");
+ warning("Experimental flag -XX:+UseMemSetInBOT is known to cause instability"
+ " on sun4v; please understand that you are using at your own risk!");
+ }
+ }
+#endif // SPARC
+
return status;
}