--- /dev/null	2020-02-06 11:34:07.664987501 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahPassiveMode.cpp	2020-02-06 19:20:11.240539137 +0100
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2019, 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/shenandoahPassiveMode.hpp"
+#include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
+#include "logging/log.hpp"
+#include "logging/logTag.hpp"
+
+void ShenandoahPassiveMode::initialize_flags() const {
+  // Do not allow concurrent cycles.
+  FLAG_SET_DEFAULT(ExplicitGCInvokesConcurrent, false);
+  FLAG_SET_DEFAULT(ShenandoahImplicitGCInvokesConcurrent, false);
+
+  // Passive runs with max speed for allocation, because GC is always STW
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahPacing);
+
+  // No need for evacuation reserve with Full GC, only for Degenerated GC.
+  if (!ShenandoahDegeneratedGC) {
+    SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahEvacReserve, 0);
+  }
+
+  // Disable known barriers by default.
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahLoadRefBarrier);
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahSATBBarrier);
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahKeepAliveBarrier);
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahStoreValEnqueueBarrier);
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCASBarrier);
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCloneBarrier);
+
+  // Final configuration checks
+  // No barriers are required to run.
+}
+ShenandoahHeuristics* ShenandoahPassiveMode::initialize_heuristics() const {
+  if (ShenandoahGCHeuristics != NULL) {
+    return new ShenandoahPassiveHeuristics();
+  }
+  ShouldNotReachHere();
+  return NULL;
+}