# HG changeset patch
# User brutisso
# Date 1418806034 -3600
# Node ID 6977216c35f2b2f7569a25639aaf826837b14d32
# Parent  31f6d76f79346cddccbc2d899e7206772a9d0235
8067438: Add test to verify minimal heap size
Reviewed-by: dfazunen, ehelin

diff -r 31f6d76f7934 -r 6977216c35f2 hotspot/test/gc/TestSmallHeap.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/TestSmallHeap.java	Wed Dec 17 09:47:14 2014 +0100
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2014, 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.
+ */
+
+/**
+ * @test TestSmallHeap
+ * @bug 8067438
+ * @requires vm.gc=="null"
+ * @summary Verify that starting the VM with a small heap works
+ * @run main/othervm -Xmx4m -XX:+UseParallelGC TestSmallHeap
+ * @run main/othervm -Xmx4m -XX:+UseSerialGC TestSmallHeap
+ * @run main/othervm -Xmx4m -XX:+UseG1GC TestSmallHeap
+ * @run main/othervm -Xmx4m -XX:+UseConcMarkSweepGC -XX:CMSMarkStackSizeMax=1032 TestSmallHeap
+ *
+ * Note: It would be nice to verify the minimal supported heap size here,
+ * but that turns out to be quite tricky since we align the heap size based
+ * on the card table size. And the card table size is aligned based on the
+ * minimal pages size provided by the os. This means that on most platforms,
+ * where the minimal page size is 4k, we get a minimal heap size of 2m but
+ * on Solaris/Sparc we have a page size of 8k and get a minimal heap size
+ * of 8m.
+ * There is also no check in the VM for verifying that the maximum heap size
+ * is larger than the supported minimal heap size. This means that specifying
+ * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m).
+ * To work around these rather strange behaviors this test uses 4m for all
+ * platforms.
+ */
+
+import sun.management.ManagementFactoryHelper;
+import static com.oracle.java.testlibrary.Asserts.*;
+
+public class TestSmallHeap {
+
+    public static void main(String[] args) {
+        String maxHeap = ManagementFactoryHelper.getDiagnosticMXBean().getVMOption("MaxHeapSize").getValue();
+        String expectedMaxHeap = "4194304";
+        assertEQ(maxHeap, expectedMaxHeap);
+    }
+}