--- a/hotspot/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/shared/GCCause.java	Tue Mar 15 10:56:32 2016 +0000
+++ b/hotspot/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/shared/GCCause.java	Tue Mar 15 13:46:48 2016 +0100
@@ -35,6 +35,10 @@
   _gc_locker ("GCLocker Initiated GC"),
   _heap_inspection ("Heap Inspection Initiated GC"),
   _heap_dump ("Heap Dump Initiated GC"),
+  _wb_young_gc ("WhiteBox Initiated Young GC"),
+  _wb_conc_mark ("WhiteBox Initiated Concurrent Mark"),
+  _update_allocation_context_stats_inc ("Update Allocation Context Stats"),
+  _update_allocation_context_stats_full ("Update Allocation Context Stats"),
 
   _no_gc ("No GC"),
   _no_cause_specified ("Unknown GCCause"),
@@ -56,6 +60,9 @@
   _g1_humongous_allocation ("G1 Humongous Allocation"),
 
   _last_ditch_collection ("Last ditch collection"),
+
+  _dcmd_gc_run ("Diagnostic Command"),
+
   _last_gc_cause ("ILLEGAL VALUE - last gc cause - ILLEGAL VALUE");
 
   private final String value;

--- a/hotspot/src/share/vm/gc/shared/gcCause.hpp	Tue Mar 15 10:56:32 2016 +0000
+++ b/hotspot/src/share/vm/gc/shared/gcCause.hpp	Tue Mar 15 13:46:48 2016 +0100
@@ -33,6 +33,9 @@
 // use of this class grows, we should split it into public
 // and implementation-private "causes".
 //
+// The definitions in the SA code should be kept in sync
+// with the definitions here.
+//
 
 class GCCause : public AllStatic {
  public:

--- a/hotspot/test/gc/arguments/TestSelectDefaultGC.java	Tue Mar 15 10:56:32 2016 +0000
+++ b/hotspot/test/gc/arguments/TestSelectDefaultGC.java	Tue Mar 15 13:46:48 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,9 +27,9 @@
  * @bug 8068582
  * @key gc
  * @library /testlibrary
+ * @requires vm.gc=="null"
  * @modules java.base/sun.misc
  *          java.management
- * @ignore 8148239
  * @run driver TestSelectDefaultGC
  */
 
@@ -41,24 +41,40 @@
         output.shouldMatch(" " + option + " .*=.* " + value + " ");
     }
 
-    public static void main(String[] args) throws Exception {
+    public static void testDefaultGC(boolean actAsServer) throws Exception {
+        String[] args = new String[] {
+          "-XX:" + (actAsServer ? "+" : "-") + "AlwaysActAsServerClassMachine",
+          "-XX:" + (actAsServer ? "-" : "+") + "NeverActAsServerClassMachine",
+          "-XX:+PrintFlagsFinal",
+          "-version"
+        };
+
         // Start VM without specifying GC
-        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+PrintFlagsFinal", "-version");
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args);
         OutputAnalyzer output = new OutputAnalyzer(pb.start());
         output.shouldHaveExitValue(0);
 
-        boolean isServerVM = Platform.isServer();
-        boolean isEmbeddedVM = Platform.isEmbedded();
+        final boolean isServer = actAsServer;
+        final boolean isEmbedded = Platform.isEmbedded();
 
         // Verify GC selection
-        // G1 is default for non-embedded server VMs
-        assertVMOption(output, "UseG1GC",            isServerVM && !isEmbeddedVM);
-        // Parallel is default for embedded server VMs
-        assertVMOption(output, "UseParallelGC",      isServerVM && isEmbeddedVM);
-        assertVMOption(output, "UseParallelOldGC",   isServerVM && isEmbeddedVM);
-        // Serial is default for non-server VMs
-        assertVMOption(output, "UseSerialGC",        !isServerVM);
+        // G1 is default for non-embedded server class machines
+        assertVMOption(output, "UseG1GC",            isServer && !isEmbedded);
+        // Parallel is default for embedded server class machines
+        assertVMOption(output, "UseParallelGC",      isServer && isEmbedded);
+        assertVMOption(output, "UseParallelOldGC",   isServer && isEmbedded);
+        // Serial is default for non-server class machines
+        assertVMOption(output, "UseSerialGC",        !isServer);
+        // CMS is never default
         assertVMOption(output, "UseConcMarkSweepGC", false);
         assertVMOption(output, "UseParNewGC",        false);
     }
+
+    public static void main(String[] args) throws Exception {
+        // Test server class machine
+        testDefaultGC(false);
+
+        // Test non-server class machine
+        testDefaultGC(true);
+    }
 }