| /* |
| * Copyright (c) 2014, 2016, 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 8152239 |
| * @requires vm.gc=="null" |
| * @summary Verify that starting the VM with a small heap works |
| * @library /test/lib |
| * @modules java.base/jdk.internal.misc |
| * @build sun.hotspot.WhiteBox |
| * @run main ClassFileInstaller sun.hotspot.WhiteBox |
| * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestSmallHeap |
| */ |
| |
| /* Note: It would be nice to verify the minimal supported heap size here, |
| * but 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 4m. And on platforms where the page size is 64k |
| * we get a minimal heap size of 32m. We never use large pages for the card table. |
| * |
| * There is also no check in the VM for verifying that the maximum heap size |
| * is larger than the supported minimal heap size. |
| * |
| * To work around these behaviors this test uses -Xmx4m but then |
| * calculates what the expected heap size should be. The calculation is a |
| * simplified version of the code in the VM. We assume that the card table will |
| * use one page. Each byte in the card table corresponds to 512 bytes on the heap. |
| * So, the expected heap size is page_size * 512. |
| * |
| * There is no formal requirement for the minimal value of the maximum heap size |
| * the VM should support. In most cases the VM could start with -Xmx2m. |
| * But with 2m limit GC could be triggered before VM initialization completed. |
| * Therefore we start the VM with 4M heap. |
| */ |
| |
| import jdk.test.lib.Asserts; |
| import jdk.test.lib.process.OutputAnalyzer; |
| import jdk.test.lib.process.ProcessTools; |
| |
| import java.util.LinkedList; |
| |
| import sun.hotspot.WhiteBox; |
| |
| public class TestSmallHeap { |
| |
| public static void main(String[] args) throws Exception { |
| // Do all work in the VM driving the test, the VM |
| // with the small heap size should do as little as |
| // possible to avoid hitting an OOME. |
| WhiteBox wb = WhiteBox.getWhiteBox(); |
| int pageSize = wb.getVMPageSize(); |
| int heapBytesPerCard = 512; |
| long expectedMaxHeap = pageSize * heapBytesPerCard; |
| |
| verifySmallHeapSize("-XX:+UseParallelGC", expectedMaxHeap); |
| verifySmallHeapSize("-XX:+UseSerialGC", expectedMaxHeap); |
| verifySmallHeapSize("-XX:+UseG1GC", expectedMaxHeap); |
| verifySmallHeapSize("-XX:+UseConcMarkSweepGC", expectedMaxHeap); |
| } |
| |
| private static void verifySmallHeapSize(String gc, long expectedMaxHeap) throws Exception { |
| long minMaxHeap = 4 * 1024 * 1024; |
| LinkedList<String> vmOptions = new LinkedList<>(); |
| vmOptions.add(gc); |
| vmOptions.add("-Xmx" + minMaxHeap); |
| vmOptions.add("-XX:+PrintFlagsFinal"); |
| vmOptions.add(VerifyHeapSize.class.getName()); |
| |
| ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(vmOptions.toArray(new String[0])); |
| OutputAnalyzer analyzer = new OutputAnalyzer(pb.start()); |
| analyzer.shouldHaveExitValue(0); |
| |
| expectedMaxHeap = Math.max(expectedMaxHeap, minMaxHeap); |
| long maxHeapSize = Long.parseLong(analyzer.firstMatch("MaxHeapSize.+=\\s+(\\d+)",1)); |
| long actualHeapSize = Long.parseLong(analyzer.firstMatch(VerifyHeapSize.actualMsg + "(\\d+)",1)); |
| Asserts.assertEQ(maxHeapSize, expectedMaxHeap); |
| Asserts.assertLessThanOrEqual(actualHeapSize, maxHeapSize); |
| } |
| } |
| |
| class VerifyHeapSize { |
| public static final String actualMsg = "Actual heap size: "; |
| |
| public static void main(String args[]) { |
| // Avoid string concatenation |
| System.out.print(actualMsg); |
| System.out.println(Runtime.getRuntime().maxMemory()); |
| } |
| } |