diff --git a/src/hotspot/share/gc/serial/serialHeap.cpp b/src/hotspot/share/gc/serial/serialHeap.cpp
index b4cef87626278..933dc12f59e1c 100644
--- a/src/hotspot/share/gc/serial/serialHeap.cpp
+++ b/src/hotspot/share/gc/serial/serialHeap.cpp
@@ -624,6 +624,7 @@ void SerialHeap::do_collection(bool           full,
     CodeCache::on_gc_marking_cycle_start();
 
     ClassUnloadingContext ctx(1 /* num_nmethod_unlink_workers */,
+                              false /* unregister_nmethods_during_purge */,
                               false /* lock_codeblob_free_separately */);
 
     collect_generation(_old_gen,
@@ -682,7 +683,11 @@ void SerialHeap::verify_nmethod(nmethod* nm) {
 }
 
 void SerialHeap::prune_scavengable_nmethods() {
-  ScavengableNMethods::prune_nmethods();
+  ScavengableNMethods::prune_nmethods_not_into_young();
+}
+
+void SerialHeap::prune_unlinked_nmethods() {
+  ScavengableNMethods::prune_unlinked_nmethods();
 }
 
 HeapWord* SerialHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
@@ -808,10 +813,6 @@ void SerialHeap::process_roots(ScanningOption so,
   DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
 }
 
-void SerialHeap::gen_process_weak_roots(OopClosure* root_closure) {
-  WeakProcessor::oops_do(root_closure);
-}
-
 bool SerialHeap::no_allocs_since_save_marks() {
   return _young_gen->no_allocs_since_save_marks() &&
          _old_gen->no_allocs_since_save_marks();
@@ -1001,15 +1002,6 @@ void SerialHeap::save_marks() {
   _old_gen->save_marks();
 }
 
-#if INCLUDE_SERIALGC
-void SerialHeap::prepare_for_compaction() {
-  // Start by compacting into same gen.
-  CompactPoint cp(_old_gen);
-  _old_gen->prepare_for_compaction(&cp);
-  _young_gen->prepare_for_compaction(&cp);
-}
-#endif // INCLUDE_SERIALGC
-
 void SerialHeap::verify(VerifyOption option /* ignored */) {
   log_debug(gc, verify)("%s", _old_gen->name());
   _old_gen->verify();
diff --git a/src/hotspot/share/gc/serial/serialHeap.hpp b/src/hotspot/share/gc/serial/serialHeap.hpp
index 5cbe283416917..d0ed728dafb28 100644
--- a/src/hotspot/share/gc/serial/serialHeap.hpp
+++ b/src/hotspot/share/gc/serial/serialHeap.hpp
@@ -200,6 +200,7 @@ class SerialHeap : public CollectedHeap {
   void verify_nmethod(nmethod* nm) override;
 
   void prune_scavengable_nmethods();
+  void prune_unlinked_nmethods();
 
   // Iteration functions.
   void object_iterate(ObjectClosure* cl) override;
@@ -305,11 +306,6 @@ class SerialHeap : public CollectedHeap {
                      CLDClosure* weak_cld_closure,
                      CodeBlobToOopClosure* code_roots);
 
-  // Apply "root_closure" to all the weak roots of the system.
-  // These include JNI weak roots, string table,
-  // and referents of reachable weak refs.
-  void gen_process_weak_roots(OopClosure* root_closure);
-
   // Set the saved marks of generations, if that makes sense.
   // In particular, if any generation might iterate over the oops
   // in other generations, it should call this method.
@@ -353,13 +349,6 @@ class SerialHeap : public CollectedHeap {
   HeapWord* mem_allocate_work(size_t size,
                               bool is_tlab);
 
-#if INCLUDE_SERIALGC
-  // For use by mark-sweep.  As implemented, mark-sweep-compact is global
-  // in an essential way: compaction is performed across generations, by
-  // iterating over spaces.
-  void prepare_for_compaction();
-#endif
-
   // Save the tops of the spaces in all generations
   void record_gen_tops_before_GC() PRODUCT_RETURN;