1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /** 25 * @test TestSmallHeap 26 * @bug 8067438 27 * @requires vm.gc=="null" 28 * @summary Verify that starting the VM with a small heap works 29 * @run main/othervm -Xmx4m -XX:+UseParallelGC TestSmallHeap 30 * @run main/othervm -Xmx4m -XX:+UseSerialGC TestSmallHeap 31 * @run main/othervm -Xmx4m -XX:+UseG1GC TestSmallHeap 32 * @run main/othervm -Xmx4m -XX:+UseConcMarkSweepGC -XX:CMSMarkStackSizeMax=1032 TestSmallHeap 33 * 34 * Note: It would be nice to verify the minimal supported heap size here, 35 * but that turns out to be quite tricky since we align the heap size based 36 * on the card table size. And the card table size is aligned based on the 37 * minimal pages size provided by the os. This means that on most platforms, 38 * where the minimal page size is 4k, we get a minimal heap size of 2m but 39 * on Solaris/Sparc we have a page size of 8k and get a minimal heap size 40 * of 8m. 41 * There is also no check in the VM for verifying that the maximum heap size 42 * is larger than the supported minimal heap size. This means that specifying 43 * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m). 44 * To work around these rather strange behaviors this test uses 4m for all 45 * platforms. 46 */ 47 48 import sun.management.ManagementFactoryHelper; 49 import static com.oracle.java.testlibrary.Asserts.*; 50 51 public class TestSmallHeap { 52 53 public static void main(String[] args) { 54 String maxHeap = ManagementFactoryHelper.getDiagnosticMXBean().getVMOption("MaxHeapSize").getValue(); 55 String expectedMaxHeap = "4194304"; 56 assertEQ(maxHeap, expectedMaxHeap); 57 } 58 }