--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zWorkers.hpp	2018-06-08 19:46:50.166020933 +0200
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2015, 2017, 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_GC_Z_ZWORKERS_HPP
+#define SHARE_GC_Z_ZWORKERS_HPP
+
+#include "gc/shared/workgroup.hpp"
+#include "memory/allocation.hpp"
+
+class ZTask;
+
+class ZWorkers {
+private:
+  bool     _boost;
+  WorkGang _workers;
+
+  static uint calculate_ncpus(double share_in_percent);
+
+  void run(ZTask* task, uint nworkers);
+
+public:
+  static uint calculate_nparallel();
+  static uint calculate_nconcurrent();
+
+  ZWorkers();
+
+  uint nparallel() const;
+  uint nparallel_no_boost() const;
+  uint nconcurrent() const;
+  uint nconcurrent_no_boost() const;
+  uint nworkers() const;
+
+  void set_boost(bool boost);
+
+  void run_parallel(ZTask* task);
+  void run_concurrent(ZTask* task);
+
+  void threads_do(ThreadClosure* tc) const;
+  void print_threads_on(outputStream* st) const;
+};
+
+#endif // SHARE_GC_Z_ZWORKERS_HPP