--- old/src/hotspot/share/gc/serial/serialHeap.cpp	2020-08-25 10:54:37.023781478 +0200
+++ new/src/hotspot/share/gc/serial/serialHeap.cpp	2020-08-25 10:54:36.471772177 +0200
@@ -90,8 +90,8 @@
 }
 
 void SerialHeap::young_process_roots(StrongRootsScope* scope,
-                                     OopsInGenClosure* root_closure,
-                                     OopsInGenClosure* old_gen_closure,
+                                     OopIterateClosure* root_closure,
+                                     OopIterateClosure* old_gen_closure,
                                      CLDClosure* cld_closure) {
   MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
 
@@ -99,15 +99,13 @@
                 cld_closure, cld_closure, &mark_code_closure);
 
   if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) {
-    root_closure->reset_generation();
+
   }
 
   // When collection is parallel, all threads get to cooperate to do
   // old generation scanning.
-  old_gen_closure->set_generation(_old_gen);
   rem_set()->at_younger_refs_iterate();
   old_gen()->younger_refs_iterate(old_gen_closure, scope->n_threads());
-  old_gen_closure->reset_generation();
 
   _process_strong_tasks->all_tasks_completed(scope->n_threads());
 }