diff --git a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.cpp b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.cpp
index ece4150f577e8..dfb28fd9ebb40 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.cpp
@@ -96,8 +96,7 @@ void ShenandoahGenerationalControlThread::stop_service() {
   log_debug(gc, thread)("Stopping control thread");
   MonitorLocker ml(&_control_lock, Mutex::_no_safepoint_check_flag);
   _heap->cancel_gc(GCCause::_shenandoah_stop_vm);
-  _requested_gc_cause = GCCause::_shenandoah_stop_vm;
-  notify_cancellation(ml, GCCause::_shenandoah_stop_vm);
+  notify_control_thread(ml, GCCause::_shenandoah_stop_vm);
   // We can't wait here because it may interfere with the active cycle's ability
   // to reach a safepoint (this runs on a java thread).
 }
@@ -140,7 +139,8 @@ void ShenandoahGenerationalControlThread::check_for_request(ShenandoahGCRequest&
 }
 
 ShenandoahGenerationalControlThread::GCMode ShenandoahGenerationalControlThread::prepare_for_allocation_failure_gc(ShenandoahGCRequest &request) {
-
+  // Important: not all paths update the request.generation. This is intentional.
+  // A degenerated cycle must use the same generation carried over from the previous request.
   if (_degen_point == ShenandoahGC::_degenerated_unset) {
     _degen_point = ShenandoahGC::_degenerated_outside_cycle;
     request.generation = _heap->young_generation();
@@ -633,9 +633,7 @@ void ShenandoahGenerationalControlThread::service_stw_degenerated_cycle(const Sh
 
 void ShenandoahGenerationalControlThread::request_gc(GCCause::Cause cause) {
   if (ShenandoahCollectorPolicy::is_allocation_failure(cause)) {
-    // GC should already be cancelled. Here we are just notifying the control thread to
-    // wake up and handle the cancellation request, so we don't need to set _requested_gc_cause.
-    notify_cancellation(cause);
+    notify_control_thread(cause);
   } else if (ShenandoahCollectorPolicy::should_handle_requested_gc(cause)) {
     handle_requested_gc(cause);
   }
@@ -661,7 +659,7 @@ bool ShenandoahGenerationalControlThread::request_concurrent_gc(ShenandoahGenera
     log_info(gc)("Preempting old generation mark to allow %s GC", generation->name());
     while (gc_mode() == servicing_old) {
       ShenandoahHeap::heap()->cancel_gc(GCCause::_shenandoah_concurrent_gc);
-      notify_cancellation(ml, GCCause::_shenandoah_concurrent_gc);
+      notify_control_thread(ml, GCCause::_shenandoah_concurrent_gc);
       ml.wait();
     }
     return true;
@@ -701,14 +699,15 @@ void ShenandoahGenerationalControlThread::notify_control_thread(MonitorLocker& m
   ml.notify();
 }
 
-void ShenandoahGenerationalControlThread::notify_cancellation(GCCause::Cause cause) {
+void ShenandoahGenerationalControlThread::notify_control_thread(GCCause::Cause cause) {
   MonitorLocker ml(&_control_lock, Mutex::_no_safepoint_check_flag);
-  notify_cancellation(ml, cause);
+  notify_control_thread(ml, cause);
 }
 
-void ShenandoahGenerationalControlThread::notify_cancellation(MonitorLocker& ml, GCCause::Cause cause) {
-  assert(_heap->cancelled_gc(), "GC should already be cancelled");
-  log_debug(gc,thread)("Notify control (%s): %s", gc_mode_name(gc_mode()), GCCause::to_string(cause));
+void ShenandoahGenerationalControlThread::notify_control_thread(MonitorLocker& ml, GCCause::Cause cause) {
+  assert(_control_lock.is_locked(), "Request lock must be held here");
+  log_debug(gc, thread)("Notify control (%s): %s", gc_mode_name(gc_mode()), GCCause::to_string(cause));
+  _requested_gc_cause = cause;
   ml.notify();
 }
 
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.hpp b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.hpp
index b7dbedd5e8461..13e69d2526870 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalControlThread.hpp
@@ -135,16 +135,13 @@ class ShenandoahGenerationalControlThread: public ShenandoahController {
   // Return printable name for the given gc mode.
   static const char* gc_mode_name(GCMode mode);
 
-  // Takes the request lock and updates the requested cause and generation, then notifies the control thread.
-  // The overloaded variant should be used when the _control_lock is already held.
+  // These notify the control thread after updating _requested_gc_cause and (optionally) _requested_generation.
+  // Updating the requested generation is not necessary for allocation failures nor when stopping the thread.
+  void notify_control_thread(GCCause::Cause cause);
+  void notify_control_thread(MonitorLocker& ml, GCCause::Cause cause);
   void notify_control_thread(GCCause::Cause cause, ShenandoahGeneration* generation);
   void notify_control_thread(MonitorLocker& ml, GCCause::Cause cause, ShenandoahGeneration* generation);
 
-  // Notifies the control thread, but does not update the requested cause or generation.
-  // The overloaded variant should be used when the _control_lock is already held.
-  void notify_cancellation(GCCause::Cause cause);
-  void notify_cancellation(MonitorLocker& ml, GCCause::Cause cause);
-
   // Configure the heap to age objects and regions if the aging period has elapsed.
   void maybe_set_aging_cycle();