diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/g1/g1HeapTransition.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1HeapTransition.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 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
+ * 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/g1/g1CollectedHeap.hpp"
+#include "gc/g1/g1HeapTransition.hpp"
+#include "gc/g1/g1Policy.hpp"
+#include "logging/log.hpp"
+#include "memory/metaspace.hpp"
+
+G1HeapTransition::Data::Data(G1CollectedHeap* g1_heap) {
+  _eden_length = g1_heap->eden_regions_count();
+  _survivor_length = g1_heap->survivor_regions_count();
+  _old_length = g1_heap->old_regions_count();
+  _humongous_length = g1_heap->humongous_regions_count();
+  _metaspace_used_bytes = MetaspaceAux::used_bytes();
+}
+
+G1HeapTransition::G1HeapTransition(G1CollectedHeap* g1_heap) : _g1_heap(g1_heap), _before(g1_heap) { }
+
+struct DetailedUsage : public StackObj {
+  size_t _eden_used;
+  size_t _survivor_used;
+  size_t _old_used;
+  size_t _humongous_used;
+
+  size_t _eden_region_count;
+  size_t _survivor_region_count;
+  size_t _old_region_count;
+  size_t _humongous_region_count;
+
+  DetailedUsage() :
+    _eden_used(0), _survivor_used(0), _old_used(0), _humongous_used(0),
+    _eden_region_count(0), _survivor_region_count(0), _old_region_count(0), _humongous_region_count(0) {}
+};
+
+class DetailedUsageClosure: public HeapRegionClosure {
+public:
+  DetailedUsage _usage;
+  bool doHeapRegion(HeapRegion* r) {
+    if (r->is_old()) {
+      _usage._old_used += r->used();
+      _usage._old_region_count++;
+    } else if (r->is_survivor()) {
+      _usage._survivor_used += r->used();
+      _usage._survivor_region_count++;
+    } else if (r->is_eden()) {
+      _usage._eden_used += r->used();
+      _usage._eden_region_count++;
+    } else if (r->is_humongous()) {
+      _usage._humongous_used += r->used();
+      _usage._humongous_region_count++;
+    } else {
+      assert(r->used() == 0, "Expected used to be 0 but it was " SIZE_FORMAT, r->used());
+    }
+    return false;
+  }
+};
+
+void G1HeapTransition::print() {
+  Data after(_g1_heap);
+
+  size_t eden_capacity_length_after_gc = _g1_heap->g1_policy()->young_list_target_length() - after._survivor_length;
+  size_t survivor_capacity_length_after_gc = _g1_heap->g1_policy()->max_survivor_regions();
+
+  DetailedUsage usage;
+  if (log_is_enabled(Trace, gc, heap)) {
+    DetailedUsageClosure blk;
+    _g1_heap->heap_region_iterate(&blk);
+    usage = blk._usage;
+    assert(usage._eden_region_count == 0, "Expected no eden regions, but got " SIZE_FORMAT, usage._eden_region_count);
+    assert(usage._survivor_region_count == after._survivor_length, "Expected survivors to be " SIZE_FORMAT " but was " SIZE_FORMAT,
+        after._survivor_length, usage._survivor_region_count);
+    assert(usage._old_region_count == after._old_length, "Expected old to be " SIZE_FORMAT " but was " SIZE_FORMAT,
+        after._old_length, usage._old_region_count);
+    assert(usage._humongous_region_count == after._humongous_length, "Expected humongous to be " SIZE_FORMAT " but was " SIZE_FORMAT,
+        after._humongous_length, usage._humongous_region_count);
+  }
+
+  log_info(gc, heap)("Eden regions: " SIZE_FORMAT "->" SIZE_FORMAT "("  SIZE_FORMAT ")",
+                     _before._eden_length, after._eden_length, eden_capacity_length_after_gc);
+  log_trace(gc, heap)(" Used: 0K, Waste: 0K");
+
+  log_info(gc, heap)("Survivor regions: " SIZE_FORMAT "->" SIZE_FORMAT "("  SIZE_FORMAT ")",
+                     _before._survivor_length, after._survivor_length, survivor_capacity_length_after_gc);
+  log_trace(gc, heap)(" Used: " SIZE_FORMAT "K, Waste: " SIZE_FORMAT "K",
+      usage._survivor_used / K, ((after._survivor_length * HeapRegion::GrainBytes) - usage._survivor_used) / K);
+
+  log_info(gc, heap)("Old regions: " SIZE_FORMAT "->" SIZE_FORMAT,
+                     _before._old_length, after._old_length);
+  log_trace(gc, heap)(" Used: " SIZE_FORMAT "K, Waste: " SIZE_FORMAT "K",
+      usage._old_used / K, ((after._old_length * HeapRegion::GrainBytes) - usage._old_used) / K);
+
+  log_info(gc, heap)("Humongous regions: " SIZE_FORMAT "->" SIZE_FORMAT,
+                     _before._humongous_length, after._humongous_length);
+  log_trace(gc, heap)(" Used: " SIZE_FORMAT "K, Waste: " SIZE_FORMAT "K",
+      usage._humongous_used / K, ((after._humongous_length * HeapRegion::GrainBytes) - usage._humongous_used) / K);
+
+  MetaspaceAux::print_metaspace_change(_before._metaspace_used_bytes);
+}