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