diff -r 8b6cc0bb93d0 -r 9186be5c78ba src/hotspot/share/gc/shenandoah/shenandoahConcurrentRoots.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentRoots.cpp	Wed Nov 27 06:36:41 2019 -0800
+++ b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentRoots.cpp	Wed Nov 27 11:52:57 2019 -0500
@@ -32,9 +32,21 @@
 }
 
 bool ShenandoahConcurrentRoots::should_do_concurrent_roots() {
-  ShenandoahHeap* const heap = ShenandoahHeap::heap();
-  bool stw_gc_in_progress = heap->is_full_gc_in_progress() ||
-                            heap->is_degenerated_gc_in_progress();
   return can_do_concurrent_roots() &&
-         !stw_gc_in_progress;
+         !ShenandoahHeap::heap()->is_stw_gc_in_progress();
 }
+
+bool ShenandoahConcurrentRoots::can_do_concurrent_class_unloading() {
+#if defined(X86) && !defined(SOLARIS)
+  return ShenandoahCodeRootsStyle == 2 &&
+         ClassUnloading &&
+         strcmp(ShenandoahGCMode, "traversal") != 0;
+#else
+  return false;
+#endif
+}
+
+bool ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() {
+  return can_do_concurrent_class_unloading() &&
+         !ShenandoahHeap::heap()->is_stw_gc_in_progress();
+}