8057824: methods to copy allocation context statistics

Reviewed-by: mikael, jmasa, tschatzl

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

@@ -1250,6 +1250,11 @@ public:
   // The same as above but assume that the caller holds the Heap_lock.
   void collect_locked(GCCause::Cause cause);
 
+  virtual void copy_allocation_context_stats(const jint* contexts,
+                                             jlong* totals,
+                                             jbyte* accuracy,
+                                             jint len);
+
   // True iff an evacuation has failed in the most-recent collection.
   bool evacuation_failed() { return _evacuation_failed; }
 

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2014, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.hpp"
+
+void G1CollectedHeap::copy_allocation_context_stats(const jint* contexts,
+                                                    jlong* totals,
+                                                    jbyte* accuracy,
+                                                    jint len) {
+}

hotspot/src/share/vm/gc_interface/collectedHeap.hpp

@@ -640,6 +640,15 @@ class CollectedHeap : public CHeapObj<mtInternal> {
   // actual number may be germane.
   static bool use_parallel_gc_threads() { return ParallelGCThreads > 0; }
 
+  // Copy the current allocation context statistics for the specified contexts.
+  // For each context in contexts, set the corresponding entries in the totals
+  // and accuracy arrays to the current values held by the statistics.  Each
+  // array should be of length len.
+  virtual void copy_allocation_context_stats(const jint* contexts,
+                                             jlong* totals,
+                                             jbyte* accuracy,
+                                             jint len) { }
+
   /////////////// Unit tests ///////////////
 
   NOT_PRODUCT(static void test_is_in();)