--- /dev/null	2018-12-03 11:58:50.256341286 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahWorkGroup.cpp	2018-12-03 17:48:58.399757862 +0100
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+
+#include "gc/shenandoah/shenandoahHeap.inline.hpp"
+#include "gc/shenandoah/shenandoahThreadLocalData.hpp"
+#include "gc/shenandoah/shenandoahWorkGroup.hpp"
+#include "gc/shenandoah/shenandoahTaskqueue.hpp"
+
+#include "logging/log.hpp"
+
+ShenandoahWorkerScope::ShenandoahWorkerScope(WorkGang* workers, uint nworkers, const char* msg, bool check) :
+  _workers(workers) {
+  assert(msg != NULL, "Missing message");
+
+  _n_workers = _workers->update_active_workers(nworkers);
+  assert(_n_workers <= nworkers, "Must be");
+
+  log_info(gc, task)("Using %u of %u workers for %s",
+    _n_workers, ShenandoahHeap::heap()->max_workers(), msg);
+
+  if (check) {
+    ShenandoahHeap::heap()->assert_gc_workers(_n_workers);
+  }
+}
+
+ShenandoahWorkerScope::~ShenandoahWorkerScope() {
+  assert(_workers->active_workers() == _n_workers,
+    "Active workers can not be changed within this scope");
+}
+
+ShenandoahPushWorkerScope::ShenandoahPushWorkerScope(WorkGang* workers, uint nworkers, bool check) :
+  _old_workers(workers->active_workers()),
+  _workers(workers) {
+  _n_workers = _workers->update_active_workers(nworkers);
+  assert(_n_workers <= nworkers, "Must be");
+
+  // bypass concurrent/parallel protocol check for non-regular paths, e.g. verifier, etc.
+  if (check) {
+    ShenandoahHeap::heap()->assert_gc_workers(_n_workers);
+  }
+}
+
+ShenandoahPushWorkerScope::~ShenandoahPushWorkerScope() {
+  assert(_workers->active_workers() == _n_workers,
+    "Active workers can not be changed within this scope");
+  // Restore old worker value
+  uint nworkers = _workers->update_active_workers(_old_workers);
+  assert(nworkers == _old_workers, "Must be able to restore");
+}
+
+ShenandoahPushWorkerQueuesScope::ShenandoahPushWorkerQueuesScope(WorkGang* workers, ShenandoahObjToScanQueueSet* queues, uint nworkers, bool check) :
+  ShenandoahPushWorkerScope(workers, nworkers, check), _queues(queues) {
+  _queues->reserve(_n_workers);
+}
+
+ShenandoahPushWorkerQueuesScope::~ShenandoahPushWorkerQueuesScope() {
+  // Restore old worker value
+  _queues->reserve(_old_workers);
+}
+
+AbstractGangWorker* ShenandoahWorkGang::install_worker(uint which) {
+  AbstractGangWorker* worker = WorkGang::install_worker(which);
+  ShenandoahThreadLocalData::create(worker);
+  if (_initialize_gclab) {
+    ShenandoahThreadLocalData::initialize_gclab(worker);
+  }
+  return worker;
+}