--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -1567,6 +1567,7 @@
 
   // Initialize the G1EvacuationFailureALot counters and flags.
   NOT_PRODUCT(reset_evacuation_should_fail();)
+  _gc_tracer_stw->initialize();
 
   guarantee(_task_queues != NULL, "task_queues allocation failure.");
 }

--- a/src/hotspot/share/gc/g1/g1HeapRegionEventSender.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/gc/g1/g1HeapRegionEventSender.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -27,6 +27,7 @@
 #include "gc/g1/heapRegion.hpp"
 #include "g1HeapRegionEventSender.hpp"
 #include "jfr/jfrEvents.hpp"
+#include "runtime/vmThread.hpp"
 
 class DumpEventInfoClosure : public HeapRegionClosure {
 public:
@@ -41,9 +42,17 @@
   }
 };
 
+class VM_G1SendHeapRegionInfoEvents : public VM_Operation {
+  virtual void doit() {
+    DumpEventInfoClosure c;
+    G1CollectedHeap::heap()->heap_region_iterate(&c);
+  }
+  virtual VMOp_Type type() const { return VMOp_HeapIterateOperation; }
+};
 
 void G1HeapRegionEventSender::send_events() {
-  DumpEventInfoClosure c;
-
-  G1CollectedHeap::heap()->heap_region_iterate(&c);
+  if (UseG1GC) {
+    VM_G1SendHeapRegionInfoEvents op;
+    VMThread::execute(&op);
+  }
 }

--- a/src/hotspot/share/gc/g1/g1Trace.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/gc/g1/g1Trace.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -24,10 +24,53 @@
 
 #include "precompiled.hpp"
 #include "gc/g1/g1EvacuationInfo.hpp"
+#include "gc/g1/g1HeapRegionTraceType.hpp"
 #include "gc/g1/g1Trace.hpp"
 #include "gc/g1/g1YCTypes.hpp"
 #include "gc/shared/gcHeapSummary.hpp"
 #include "jfr/jfrEvents.hpp"
+#if INCLUDE_JFR
+#include "jfr/metadata/jfrSerializer.hpp"
+#endif
+
+#if INCLUDE_JFR
+class G1HeapRegionTypeConstant : public JfrSerializer {
+public:
+  void serialize(JfrCheckpointWriter& writer) {
+  static const u4 nof_entries = G1HeapRegionTraceType::G1HeapRegionTypeEndSentinel;
+  writer.write_count(nof_entries);
+  for (u4 i = 0; i < nof_entries; ++i) {
+    writer.write_key(i);
+    writer.write(G1HeapRegionTraceType::to_string((G1HeapRegionTraceType::Type)i));
+  }
+}
+};
+
+class G1YCTypeConstant : public JfrSerializer {
+public:
+  void serialize(JfrCheckpointWriter& writer) {
+    static const u4 nof_entries = G1YCTypeEndSentinel;
+    writer.write_count(nof_entries);
+    for (u4 i = 0; i < nof_entries; ++i) {
+      writer.write_key(i);
+      writer.write(G1YCTypeHelper::to_string((G1YCType)i));
+    }
+  }
+};
+
+static void register_jfr_type_constants() {
+  JfrSerializer::register_serializer(TYPE_G1HEAPREGIONTYPE, false, true,
+                                     new G1HeapRegionTypeConstant());
+
+  JfrSerializer::register_serializer(TYPE_G1YCTYPE, false, true,
+                                     new G1YCTypeConstant());
+}
+
+#endif
+
+void G1NewTracer::initialize() {
+  JFR_ONLY(register_jfr_type_constants());
+}
 
 void G1NewTracer::report_yc_type(G1YCType type) {
   _g1_young_gc_info.set_type(type);

--- a/src/hotspot/share/gc/g1/g1Trace.hpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/gc/g1/g1Trace.hpp	Wed Sep 04 09:47:55 2019 +0200
@@ -48,6 +48,7 @@
 public:
   G1NewTracer() : YoungGCTracer(G1New) {}
 
+  void initialize();
   void report_yc_type(G1YCType type);
   void report_gc_end_impl(const Ticks& timestamp, TimePartitions* time_partitions);
   void report_evacuation_info(G1EvacuationInfo* info);

--- a/src/hotspot/share/jfr/periodic/jfrPeriodic.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/jfr/periodic/jfrPeriodic.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -32,7 +32,6 @@
 #include "classfile/systemDictionary.hpp"
 #include "code/codeCache.hpp"
 #include "compiler/compileBroker.hpp"
-#include "gc/g1/g1HeapRegionEventSender.hpp"
 #include "gc/shared/gcConfiguration.hpp"
 #include "gc/shared/gcTrace.hpp"
 #include "gc/shared/gcVMOperations.hpp"
@@ -65,6 +64,9 @@
 #include "services/threadService.hpp"
 #include "utilities/exceptions.hpp"
 #include "utilities/globalDefinitions.hpp"
+#if INCLUDE_G1GC
+#include "gc/g1/g1HeapRegionEventSender.hpp"
+#endif
 #if INCLUDE_SHENANDOAHGC
 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
 #endif
@@ -323,18 +325,8 @@
   VMThread::execute(&op);
 }
 
-class VM_G1SendHeapRegionInfoEvents : public VM_Operation {
-  virtual void doit() {
-    G1HeapRegionEventSender::send_events();
-  }
-  virtual VMOp_Type type() const { return VMOp_HeapIterateOperation; }
-};
-
 TRACE_REQUEST_FUNC(G1HeapRegionInformation) {
-  if (UseG1GC) {
-    VM_G1SendHeapRegionInfoEvents op;
-    VMThread::execute(&op);
-  }
+  G1GC_ONLY(G1HeapRegionEventSender::send_events());
 }
 
 // Java Mission Control (JMC) uses (Java) Long.MIN_VALUE to describe that a

--- a/src/hotspot/share/jfr/recorder/checkpoint/types/jfrType.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/jfr/recorder/checkpoint/types/jfrType.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -56,10 +56,6 @@
 #include "opto/compile.hpp"
 #include "opto/node.hpp"
 #endif
-#if INCLUDE_G1GC
-#include "gc/g1/g1HeapRegionTraceType.hpp"
-#include "gc/g1/g1YCTypes.hpp"
-#endif
 
 // Requires a ResourceMark for get_thread_name/as_utf8
 class JfrCheckpointThreadClosure : public ThreadClosure {
@@ -188,15 +184,6 @@
   }
 }
 
-void G1HeapRegionTypeConstant::serialize(JfrCheckpointWriter& writer) {
-  static const u4 nof_entries = G1HeapRegionTraceType::G1HeapRegionTypeEndSentinel;
-  writer.write_count(nof_entries);
-  for (u4 i = 0; i < nof_entries; ++i) {
-    writer.write_key(i);
-    writer.write(G1HeapRegionTraceType::to_string((G1HeapRegionTraceType::Type)i));
-  }
-}
-
 void GCThresholdUpdaterConstant::serialize(JfrCheckpointWriter& writer) {
   static const u4 nof_entries = MetaspaceGCThresholdUpdater::Last;
   writer.write_count(nof_entries);
@@ -224,17 +211,6 @@
   }
 }
 
-void G1YCTypeConstant::serialize(JfrCheckpointWriter& writer) {
-#if INCLUDE_G1GC
-  static const u4 nof_entries = G1YCTypeEndSentinel;
-  writer.write_count(nof_entries);
-  for (u4 i = 0; i < nof_entries; ++i) {
-    writer.write_key(i);
-    writer.write(G1YCTypeHelper::to_string((G1YCType)i));
-  }
-#endif
-}
-
 static const char* reference_type_to_string(ReferenceType rt) {
   switch (rt) {
     case REF_NONE: return "None reference";

--- a/src/hotspot/share/jfr/recorder/checkpoint/types/jfrType.hpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/jfr/recorder/checkpoint/types/jfrType.hpp	Wed Sep 04 09:47:55 2019 +0200
@@ -67,11 +67,6 @@
   void serialize(JfrCheckpointWriter& writer);
 };
 
-class G1HeapRegionTypeConstant : public JfrSerializer {
- public:
-  void serialize(JfrCheckpointWriter& writer);
-};
-
 class GCThresholdUpdaterConstant : public JfrSerializer {
  public:
   void serialize(JfrCheckpointWriter& writer);
@@ -87,11 +82,6 @@
   void serialize(JfrCheckpointWriter& writer);
 };
 
-class G1YCTypeConstant : public JfrSerializer {
- public:
-  void serialize(JfrCheckpointWriter& writer);
-};
-
 class ReferenceTypeConstant : public JfrSerializer {
  public:
   void serialize(JfrCheckpointWriter& writer);

--- a/src/hotspot/share/jfr/recorder/checkpoint/types/jfrTypeManager.cpp	Wed Sep 04 09:47:51 2019 +0200
+++ b/src/hotspot/share/jfr/recorder/checkpoint/types/jfrTypeManager.cpp	Wed Sep 04 09:47:55 2019 +0200
@@ -226,11 +226,9 @@
   register_type(TYPE_GCCAUSE, false, true, new GCCauseConstant());
   register_type(TYPE_GCNAME, false, true, new GCNameConstant());
   register_type(TYPE_GCWHEN, false, true, new GCWhenConstant());
-  register_type(TYPE_G1HEAPREGIONTYPE, false, true, new G1HeapRegionTypeConstant());
   register_type(TYPE_GCTHRESHOLDUPDATER, false, true, new GCThresholdUpdaterConstant());
   register_type(TYPE_METADATATYPE, false, true, new MetadataTypeConstant());
   register_type(TYPE_METASPACEOBJECTTYPE, false, true, new MetaspaceObjectTypeConstant());
-  register_type(TYPE_G1YCTYPE, false, true, new G1YCTypeConstant());
   register_type(TYPE_REFERENCETYPE, false, true, new ReferenceTypeConstant());
   register_type(TYPE_NARROWOOPMODE, false, true, new NarrowOopModeConstant());
   register_type(TYPE_COMPILERPHASETYPE, false, true, new CompilerPhaseTypeConstant());