--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1CollectorState.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,134 @@
+/*
+ * 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
+ * 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_G1_G1COLLECTORSTATE_HPP
+#define SHARE_VM_GC_G1_G1COLLECTORSTATE_HPP
+
+#include "gc/g1/g1YCTypes.hpp"
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// Various state variables that indicate
+// the phase of the G1 collection.
+class G1CollectorState VALUE_OBJ_CLASS_SPEC {
+  // Indicates whether we are in "full young" or "mixed" GC mode.
+  bool _gcs_are_young;
+  // Was the last GC "young"?
+  bool _last_gc_was_young;
+  // Is this the "last young GC" before we start doing mixed GCs?
+  // Set after a concurrent mark has completed.
+  bool _last_young_gc;
+
+  // If initiate_conc_mark_if_possible() is set at the beginning of a
+  // pause, it is a suggestion that the pause should start a marking
+  // cycle by doing the initial-mark work. However, it is possible
+  // that the concurrent marking thread is still finishing up the
+  // previous marking cycle (e.g., clearing the next marking
+  // bitmap). If that is the case we cannot start a new cycle and
+  // we'll have to wait for the concurrent marking thread to finish
+  // what it is doing. In this case we will postpone the marking cycle
+  // initiation decision for the next pause. When we eventually decide
+  // to start a cycle, we will set _during_initial_mark_pause which
+  // will stay true until the end of the initial-mark pause and it's
+  // the condition that indicates that a pause is doing the
+  // initial-mark work.
+  volatile bool _during_initial_mark_pause;
+
+  // At the end of a pause we check the heap occupancy and we decide
+  // whether we will start a marking cycle during the next pause. If
+  // we decide that we want to do that, we will set this parameter to
+  // true. So, this parameter will stay true between the end of a
+  // pause and the beginning of a subsequent pause (not necessarily
+  // the next one, see the comments on the next field) when we decide
+  // that we will indeed start a marking cycle and do the initial-mark
+  // work.
+  volatile bool _initiate_conc_mark_if_possible;
+
+  // NOTE: if some of these are synonyms for others,
+  // the redundant fields should be eliminated. XXX
+  bool _during_marking;
+  bool _mark_in_progress;
+  bool _in_marking_window;
+  bool _in_marking_window_im;
+
+  bool _full_collection;
+
+  public:
+    G1CollectorState() :
+      _gcs_are_young(true),
+      _last_gc_was_young(false),
+      _last_young_gc(false),
+
+      _during_initial_mark_pause(false),
+      _initiate_conc_mark_if_possible(false),
+
+      _during_marking(false),
+      _mark_in_progress(false),
+      _in_marking_window(false),
+      _in_marking_window_im(false),
+      _full_collection(false) {}
+
+  // Setters
+  void set_gcs_are_young(bool v) { _gcs_are_young = v; }
+  void set_last_gc_was_young(bool v) { _last_gc_was_young = v; }
+  void set_last_young_gc(bool v) { _last_young_gc = v; }
+  void set_during_initial_mark_pause(bool v) { _during_initial_mark_pause = v; }
+  void set_initiate_conc_mark_if_possible(bool v) { _initiate_conc_mark_if_possible = v; }
+  void set_during_marking(bool v) { _during_marking = v; }
+  void set_mark_in_progress(bool v) { _mark_in_progress = v; }
+  void set_in_marking_window(bool v) { _in_marking_window = v; }
+  void set_in_marking_window_im(bool v) { _in_marking_window_im = v; }
+  void set_full_collection(bool v) { _full_collection = v; }
+
+  // Getters
+  bool gcs_are_young() const { return _gcs_are_young; }
+  bool last_gc_was_young() const { return _last_gc_was_young; }
+  bool last_young_gc() const { return _last_young_gc; }
+  bool during_initial_mark_pause() const { return _during_initial_mark_pause; }
+  bool initiate_conc_mark_if_possible() const { return _initiate_conc_mark_if_possible; }
+  bool during_marking() const { return _during_marking; }
+  bool mark_in_progress() const { return _mark_in_progress; }
+  bool in_marking_window() const { return _in_marking_window; }
+  bool in_marking_window_im() const { return _in_marking_window_im; }
+  bool full_collection() const { return _full_collection; }
+
+  // Composite booleans (clients worry about flickering)
+  bool during_concurrent_mark() const {
+    return (_in_marking_window && !_in_marking_window_im);
+  }
+
+  G1YCType yc_type() const {
+    if (during_initial_mark_pause()) {
+      return InitialMark;
+    } else if (mark_in_progress()) {
+      return DuringMark;
+    } else if (gcs_are_young()) {
+      return Normal;
+    } else {
+      return Mixed;
+    }
+  }
+};
+
+#endif // SHARE_VM_GC_G1_G1COLLECTORSTATE_HPP