1 /* 2 * Copyright (c) 2014, 2015, 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 * @requires (vm.opt.AggressiveOpts=="null") | (vm.opt.AggressiveOpts=="false") 29 * @requires vm.compMode != "Xcomp" 30 * @summary Verify that starting the VM with a small heap works 31 * @library /testlibrary /../../test/lib 32 * @modules java.management/sun.management 33 * @build TestSmallHeap 34 * @run main ClassFileInstaller sun.hotspot.WhiteBox 35 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseParallelGC TestSmallHeap 36 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseSerialGC TestSmallHeap 37 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseG1GC TestSmallHeap 38 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xmx2m -XX:+UseConcMarkSweepGC TestSmallHeap 39 */ 40 41 /* Note: It would be nice to verify the minimal supported heap size (2m) here, 42 * but we align the heap size based on the card table size. And the card table 43 * size is aligned based on the minimal pages size provided by the os. This 44 * means that on most platforms, where the minimal page size is 4k, we get a 45 * minimal heap size of 2m but on Solaris/Sparc we have a page size of 8k and 46 * get a minimal heap size of 4m. And on platforms where the page size is 64k 47 * we get a minimal heap size of 32m. We never use large pages for the card table. 48 * 49 * There is also no check in the VM for verifying that the maximum heap size 50 * is larger than the supported minimal heap size. This means that specifying 51 * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m or 32m). 52 * 53 * To work around these rather strange behaviors this test uses -Xmx2m but then 54 * calculates what the expected heap size should be. The calculation is a 55 * simplified version of the code in the VM. We assume that the card table will 56 * use one page. Each byte in the card table corresponds to 512 bytes on the heap. 57 * So, the expected heap size is page_size * 512. 58 */ 59 60 import jdk.test.lib.*; 61 import com.sun.management.HotSpotDiagnosticMXBean; 62 import java.lang.management.ManagementFactory; 63 import static jdk.test.lib.Asserts.*; 64 65 import sun.hotspot.WhiteBox; 66 67 public class TestSmallHeap { 68 69 public static void main(String[] args) { 70 WhiteBox wb = WhiteBox.getWhiteBox(); 71 int pageSize = wb.getVMPageSize(); 72 int heapBytesPerCard = 512; 73 long expectedMaxHeap = pageSize * heapBytesPerCard; 74 String maxHeap 75 = ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 76 .getVMOption("MaxHeapSize").getValue(); 77 assertEQ(Long.parseLong(maxHeap), expectedMaxHeap); 78 } 79 }