Summary: use vm_global() OopStorage for system dictionary roots removed SystemDictionary::oops_do in all the GCs. Tested with tier1-6. open webrev at http://cr.openjdk.java.net/~coleenp/2020/8246340.01/webrev bug link https://bugs.openjdk.java.net/browse/JDK-8246340 Thanks, Coleen