--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/gc/z/TestSmallHeap.java	Wed Nov 20 10:37:46 2019 +0100
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+
+package gc.z;
+
+/*
+ * @test TestSmallHeap
+ * @requires vm.gc.Z & !vm.graal.enabled
+ * @summary Test ZGC with small heaps
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx8M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx16M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx32M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx64M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx128M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx256M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx512M gc.z.TestSmallHeap
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx1024M gc.z.TestSmallHeap
+ */
+
+import java.lang.ref.Reference;
+
+public class TestSmallHeap {
+    public static void main(String[] args) throws Exception {
+        final long maxCapacity = Runtime.getRuntime().maxMemory();
+        System.out.println("Max Capacity " + maxCapacity + " bytes");
+
+        // Allocate byte arrays of increasing length, so that
+        // all allocaion paths (small/medium/large) are tested.
+        for (int length = 16; length <= maxCapacity / 16; length *= 2) {
+            System.out.println("Allocating " + length + " bytes");
+            Reference.reachabilityFence(new byte[length]);
+        }
+
+        System.out.println("Success");
+    }
+}