--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegionCounters.hpp	Mon Dec 10 15:47:44 2018 +0100
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONCOUNTERS_HPP
+#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONCOUNTERS_HPP
+
+#include "memory/allocation.hpp"
+
+/**
+ * This provides the following in JVMStat:
+ *
+ * constants:
+ * - sun.gc.shenandoah.regions.timestamp    the timestamp for this sample
+ * - sun.gc.shenandoah.regions.max_regions  maximum number of regions
+ * - sun.gc.shenandoah.regions.region_size  size per region, in kilobytes
+ *
+ * variables:
+ * - sun.gc.shenandoah.regions.status       current GC status:
+ *     - bit 0 set when marking in progress
+ *     - bit 1 set when evacuation in progress
+ *     - bit 2 set when update refs in progress
+ *     - bit 3 set when traversal in progress
+ *
+ * two variable counters per region, with $max_regions (see above) counters:
+ * - sun.gc.shenandoah.regions.region.$i.data
+ * where $ is the region number from 0 <= i < $max_regions
+ *
+ * .data is in the following format:
+ * - bits 0-6    used memory in percent
+ * - bits 7-13   live memory in percent
+ * - bits 14-20  tlab allocated memory in percent
+ * - bits 21-27  gclab allocated memory in percent
+ * - bits 28-34  shared allocated memory in percent
+ * - bits 35-41  <reserved>
+ * - bits 42-50  <reserved>
+ * - bits 51-57  <reserved>
+ * - bits 58-63  status
+ *      - bits describe the state as recorded in ShenandoahHeapRegion
+ */
+class ShenandoahHeapRegionCounters : public CHeapObj<mtGC>  {
+private:
+  static const jlong PERCENT_MASK = 0x7f;
+  static const jlong STATUS_MASK  = 0x3f;
+
+  static const jlong USED_SHIFT   = 0;
+  static const jlong LIVE_SHIFT   = 7;
+  static const jlong TLAB_SHIFT   = 14;
+  static const jlong GCLAB_SHIFT  = 21;
+  static const jlong SHARED_SHIFT = 28;
+
+  static const jlong STATUS_SHIFT = 58;
+
+  char* _name_space;
+  PerfLongVariable** _regions_data;
+  PerfLongVariable* _timestamp;
+  PerfLongVariable* _status;
+  volatile jlong _last_sample_millis;
+
+public:
+  ShenandoahHeapRegionCounters();
+  ~ShenandoahHeapRegionCounters();
+  void update();
+};
+
+#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGIONCOUNTERS_HPP