| /* |
| * Copyright (c) 2014, 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 TestHumongousShrinkHeap |
| * @bug 8036025 8056043 |
| * @summary Verify that heap shrinks after GC in the presence of fragmentation |
| * due to humongous objects |
| * @library /testlibrary |
| * @run main/othervm -XX:-ExplicitGCInvokesConcurrent -XX:MinHeapFreeRatio=10 |
| * -XX:MaxHeapFreeRatio=12 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -verbose:gc |
| * TestHumongousShrinkHeap |
| */ |
| |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.MemoryUsage; |
| import java.util.ArrayList; |
| import java.util.List; |
| import sun.management.ManagementFactoryHelper; |
| import static com.oracle.java.testlibrary.Asserts.*; |
| |
| public class TestHumongousShrinkHeap { |
| |
| public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; |
| public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; |
| |
| private static final List<List<byte[]>> garbage = new ArrayList(); |
| private static final int REGION_SIZE = 1024 * 1024; // 1M |
| private static final int LISTS_COUNT = 10; |
| private static final int HUMON_SIZE = Math.round(.9f * REGION_SIZE); |
| private static final long AVAILABLE_MEMORY |
| = Runtime.getRuntime().freeMemory(); |
| private static final int HUMON_COUNT |
| = (int) ((AVAILABLE_MEMORY / HUMON_SIZE) |
| / LISTS_COUNT); |
| |
| |
| public static void main(String[] args) { |
| System.out.format("Running with %s max heap size. " |
| + "Will allocate humongous object of %s size %d times.%n", |
| MemoryUsagePrinter.humanReadableByteCount(AVAILABLE_MEMORY, false), |
| MemoryUsagePrinter.humanReadableByteCount(HUMON_SIZE, false), |
| HUMON_COUNT |
| ); |
| new TestHumongousShrinkHeap().test(); |
| } |
| |
| private final void test() { |
| System.gc(); |
| MemoryUsagePrinter.printMemoryUsage("init"); |
| |
| allocate(); |
| MemoryUsagePrinter.printMemoryUsage("allocated"); |
| 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, |
| ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), |
| MAX_FREE_RATIO_FLAG_NAME, |
| ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() |
| )); |
| } |
| |
| private void allocate() { |
| |
| for (int i = 0; i < LISTS_COUNT; i++) { |
| List<byte[]> stuff = new ArrayList(); |
| allocateList(stuff, HUMON_COUNT, HUMON_SIZE); |
| MemoryUsagePrinter.printMemoryUsage("allocate #" + (i+1)); |
| garbage.add(stuff); |
| } |
| } |
| |
| private void free() { |
| // do not free last one list |
| garbage.subList(0, garbage.size() - 1).clear(); |
| |
| // do not free last one element from last list |
| List stuff = garbage.get(garbage.size() - 1); |
| stuff.subList(0, stuff.size() - 1).clear(); |
| System.gc(); |
| } |
| |
| private static void allocateList(List garbage, int count, int size) { |
| for (int i = 0; i < count; i++) { |
| garbage.add(new byte[size]); |
| } |
| } |
| } |
| |
| /** |
| * Prints memory usage to standard output |
| */ |
| class MemoryUsagePrinter { |
| |
| public static String humanReadableByteCount(long bytes, boolean si) { |
| int unit = si ? 1000 : 1024; |
| if (bytes < unit) { |
| return bytes + " B"; |
| } |
| int exp = (int) (Math.log(bytes) / Math.log(unit)); |
| String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1) + (si ? "" : "i"); |
| return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre); |
| } |
| |
| 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, |
| humanReadableByteCount(memusage.getInit(), false), |
| humanReadableByteCount(memusage.getUsed(), false), |
| humanReadableByteCount(memusage.getCommitted(), false), |
| freeratio * 100 |
| ); |
| } |
| } |