--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zThread.cpp	2018-06-01 22:31:09.137112242 +0200
@@ -0,0 +1,74 @@
+/*
+ * 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.
+ */
+
+#include "precompiled.hpp"
+#include "gc/z/zThread.hpp"
+#include "runtime/thread.hpp"
+#include "utilities/debug.hpp"
+
+__thread bool      ZThread::_initialized;
+__thread uintptr_t ZThread::_id;
+__thread bool      ZThread::_is_vm;
+__thread bool      ZThread::_is_java;
+__thread bool      ZThread::_is_worker;
+__thread uint      ZThread::_worker_id;
+
+void ZThread::initialize() {
+  assert(!_initialized, "Already initialized");
+  const Thread* const thread = Thread::current();
+  _initialized = true;
+  _id = (uintptr_t)thread;
+  _is_vm = thread->is_VM_thread();
+  _is_java = thread->is_Java_thread();
+  _is_worker = thread->is_Worker_thread();
+  _worker_id = (uint)-1;
+}
+
+const char* ZThread::name() {
+  const Thread* const thread = Thread::current();
+  if (thread->is_Named_thread()) {
+    const NamedThread* const named = (const NamedThread*)thread;
+    return named->name();
+  } else if (thread->is_Java_thread()) {
+    return "Java";
+  }
+
+  return "Unknown";
+}
+
+bool ZThread::has_worker_id() {
+  return _initialized &&
+         _is_worker &&
+         _worker_id != (uint)-1;
+}
+
+void ZThread::set_worker_id(uint worker_id) {
+  ensure_initialized();
+  assert(!has_worker_id(), "Worker id already initialized");
+  _worker_id = worker_id;
+}
+
+void ZThread::clear_worker_id() {
+  assert(has_worker_id(), "Worker id not initialized");
+  _worker_id = (uint)-1;
+}