| /* |
| * 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 TestDynShrinkHeap |
| * @bug 8016479 |
| * @requires vm.gc.Parallel & os.maxMemory > 1G |
| * @summary Verify that the heap shrinks after full GC according to the current values of the Min/MaxHeapFreeRatio flags |
| * @modules java.base/jdk.internal.misc |
| * @modules jdk.management |
| * @library /test/lib / |
| * @run main/othervm -XX:+UseAdaptiveSizePolicyWithSystemGC -XX:+UseParallelGC -XX:MinHeapFreeRatio=0 -XX:MaxHeapFreeRatio=100 -Xmx1g -verbose:gc TestDynShrinkHeap |
| */ |
| import jdk.test.lib.management.DynamicVMOption; |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.MemoryUsage; |
| import java.util.ArrayList; |
| import java.text.NumberFormat; |
| import static jdk.test.lib.Asserts.assertLessThan; |
| import com.sun.management.HotSpotDiagnosticMXBean; |
| import gc.testlibrary.Helpers; |
| |
| public class TestDynShrinkHeap { |
| |
| public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; |
| public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; |
| |
| private static ArrayList<byte[]> list = new ArrayList<>(0); |
| private static final int LEN = 512 * 1024 + 1; |
| |
| public TestDynShrinkHeap() { |
| } |
| |
| private final void test() { |
| System.gc(); |
| MemoryUsagePrinter.printMemoryUsage("init"); |
| |
| eat(); |
| MemoryUsagePrinter.printMemoryUsage("eaten"); |
| MemoryUsage muFull = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); |
| |
| free(); |
| MemoryUsagePrinter.printMemoryUsage("free"); |
| MemoryUsage muFree = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); |
| |
| assertLessThan(muFree.getCommitted(), muFull.getCommitted(), String.format( |
| "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n" |
| + "%s = %s%n%s = %s", |
| MIN_FREE_RATIO_FLAG_NAME, |
| ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) |
| .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), |
| MAX_FREE_RATIO_FLAG_NAME, |
| ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) |
| .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() |
| )); |
| } |
| |
| private void eat() { |
| for (int i = 0; i < LEN; i++) { |
| list.add(new byte[1024]); |
| } |
| MemoryUsagePrinter.printMemoryUsage("allocated " + LEN + " arrays"); |
| |
| list.subList(0, LEN / 2).clear(); |
| System.gc(); |
| MemoryUsagePrinter.printMemoryUsage("array halved"); |
| } |
| |
| private void free() { |
| int min = DynamicVMOption.getInt(MIN_FREE_RATIO_FLAG_NAME); |
| DynamicVMOption.setInt(MAX_FREE_RATIO_FLAG_NAME, min); |
| System.gc(); |
| MemoryUsagePrinter.printMemoryUsage("under pressure"); |
| } |
| |
| public static void main(String[] args) { |
| new TestDynShrinkHeap().test(); |
| } |
| } |
| |
| /** |
| * Prints memory usage to standard output |
| */ |
| class MemoryUsagePrinter { |
| |
| public static final NumberFormat NF = Helpers.numberFormatter(); |
| |
| public static void printMemoryUsage(String label) { |
| MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); |
| float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted(); |
| System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n", |
| label, |
| NF.format(memusage.getInit()), |
| NF.format(memusage.getUsed()), |
| NF.format(memusage.getCommitted()), |
| freeratio * 100 |
| ); |
| } |
| } |