--- old/src/hotspot/share/gc/shared/cardTableRS.cpp	2020-08-25 10:03:53.564501625 +0200
+++ new/src/hotspot/share/gc/shared/cardTableRS.cpp	2020-08-25 10:03:53.388498659 +0200
@@ -112,13 +112,10 @@
   }
 }
 
-void CardTableRS::younger_refs_iterate(Generation* g,
-                                       OopsInGenClosure* blk,
-                                       uint n_threads) {
+void CardTableRS::at_younger_refs_iterate() {
   // The indexing in this array is slightly odd. We want to access
   // the old generation record here, which is at index 2.
   _last_cur_val_in_gen[2] = cur_youngergen_card_val();
-  g->younger_refs_iterate(blk, n_threads);
 }
 
 inline bool ClearNoncleanCardWrapper::clear_card(CardValue* entry) {
@@ -245,12 +242,13 @@
 }
 
 void CardTableRS::younger_refs_in_space_iterate(Space* sp,
-                                                OopsInGenClosure* cl,
+                                                HeapWord* gen_boundary,
+                                                OopIterateClosure* cl,
                                                 uint n_threads) {
   verify_used_region_at_save_marks(sp);
 
   const MemRegion urasm = sp->used_region_at_save_marks();
-  non_clean_card_iterate_possibly_parallel(sp, urasm, cl, this, n_threads);
+  non_clean_card_iterate_possibly_parallel(sp, gen_boundary, urasm, cl, this, n_threads);
 }
 
 #ifdef ASSERT
@@ -624,8 +622,9 @@
 
 void CardTableRS::non_clean_card_iterate_possibly_parallel(
   Space* sp,
+  HeapWord* gen_boundary,
   MemRegion mr,
-  OopsInGenClosure* cl,
+  OopIterateClosure* cl,
   CardTableRS* ct,
   uint n_threads)
 {
@@ -638,7 +637,7 @@
       // This is the single-threaded version used by DefNew.
       const bool parallel = false;
 
-      DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(), cl->gen_boundary(), parallel);
+      DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(), gen_boundary, parallel);
       ClearNoncleanCardWrapper clear_cl(dcto_cl, ct, parallel);
 
       clear_cl.do_MemRegion(mr);
@@ -647,7 +646,7 @@
 }
 
 void CardTableRS::non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,
-                                                       OopsInGenClosure* cl, CardTableRS* ct,
+                                                       OopIterateClosure* cl, CardTableRS* ct,
                                                        uint n_threads) {
   fatal("Parallel gc not supported here.");
 }