--- old/src/jdk.jfr/share/classes/jdk/jfr/internal/instrument/JDKEvents.java	2020-03-05 14:19:30.869245045 +0800
+++ new/src/jdk.jfr/share/classes/jdk/jfr/internal/instrument/JDKEvents.java	2020-03-05 14:19:30.737240236 +0800
@@ -28,9 +28,14 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import jdk.internal.access.JavaNioAccess;
+import jdk.internal.access.SharedSecrets;
+import jdk.internal.misc.VM;
+
 import jdk.jfr.Event;
 import jdk.jfr.events.ActiveRecordingEvent;
 import jdk.jfr.events.ActiveSettingEvent;
+import jdk.jfr.events.DirectMemoryStatisticsEvent;
 import jdk.jfr.events.ErrorThrownEvent;
 import jdk.jfr.events.ExceptionStatisticsEvent;
 import jdk.jfr.events.ExceptionThrownEvent;
@@ -73,7 +78,8 @@
         jdk.internal.event.SecurityPropertyModificationEvent.class,
         jdk.internal.event.TLSHandshakeEvent.class,
         jdk.internal.event.X509CertificateEvent.class,
-        jdk.internal.event.X509ValidationEvent.class
+        jdk.internal.event.X509ValidationEvent.class,
+        DirectMemoryStatisticsEvent.class
     };
 
     // This is a list of the classes with instrumentation code that should be applied.
@@ -90,6 +96,7 @@
     private static final Class<?>[] targetClasses = new Class<?>[instrumentationClasses.length];
     private static final JVM jvm = JVM.getJVM();
     private static final Runnable emitExceptionStatistics = JDKEvents::emitExceptionStatistics;
+    private static final Runnable emitDirectMemoryStatistics = JDKEvents::emitDirectMemoryStatistics;
     private static boolean initializationTriggered;
 
     @SuppressWarnings("unchecked")
@@ -104,6 +111,7 @@
                 }
                 initializationTriggered = true;
                 RequestEngine.addTrustedJDKHook(ExceptionStatisticsEvent.class, emitExceptionStatistics);
+                RequestEngine.addTrustedJDKHook(DirectMemoryStatisticsEvent.class, emitDirectMemoryStatistics);
             }
         } catch (Exception e) {
             Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not initialize JDK events. " + e.getMessage());
@@ -160,5 +168,16 @@
 
     public static void remove() {
         RequestEngine.removeHook(JDKEvents::emitExceptionStatistics);
+        RequestEngine.removeHook(emitDirectMemoryStatistics);
+    }
+
+    private static void emitDirectMemoryStatistics() {
+        DirectMemoryStatisticsEvent e = new DirectMemoryStatisticsEvent();
+        JavaNioAccess.BufferPool pool = SharedSecrets.getJavaNioAccess().getDirectBufferPool();
+        e.count = pool.getCount();
+        e.totalCapacity = pool.getTotalCapacity();
+        e.memoryUsed = pool.getMemoryUsed();
+        e.maxCapacity = VM.maxDirectMemory();
+        e.commit();
     }
 }