1 /* 2 * Copyright (c) 2014, 2019, 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 package gc.g1; 25 26 /** 27 * @test TestHumongousShrinkHeap 28 * @bug 8036025 8056043 29 * @requires vm.gc.G1 30 * @summary Verify that heap shrinks after GC in the presence of fragmentation 31 * due to humongous objects 32 * @library /test/lib / 33 * @modules java.base/jdk.internal.misc 34 * @modules java.management/sun.management 35 * @run main/othervm -XX:-ExplicitGCInvokesConcurrent -XX:MinHeapFreeRatio=10 36 * -XX:MaxHeapFreeRatio=12 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -verbose:gc 37 * gc.g1.TestHumongousShrinkHeap 38 */ 39 40 import com.sun.management.HotSpotDiagnosticMXBean; 41 import java.lang.management.ManagementFactory; 42 import java.lang.management.MemoryUsage; 43 import java.util.ArrayList; 44 import java.util.List; 45 import java.text.NumberFormat; 46 import gc.testlibrary.Helpers; 47 import static jdk.test.lib.Asserts.*; 48 import jtreg.SkippedException; 49 50 public class TestHumongousShrinkHeap { 51 52 public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; 53 public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; 54 55 private static final List<List<byte[]>> garbage = new ArrayList(); 56 private static final int REGION_SIZE = 1024 * 1024; // 1M 57 private static final int LISTS_COUNT = 10; 58 private static final int HUMON_SIZE = Math.round(.9f * REGION_SIZE); 59 60 private static final long TOTAL_MEMORY = Runtime.getRuntime().totalMemory(); 61 private static final long MAX_MEMORY = Runtime.getRuntime().maxMemory(); 62 63 private static final int HUMON_COUNT = (int) ((TOTAL_MEMORY / HUMON_SIZE) / LISTS_COUNT); 64 65 public static void main(String[] args) { 66 if (HUMON_COUNT == 0) { 67 throw new SkippedException("Heap is too small"); 68 } 69 70 if (TOTAL_MEMORY + REGION_SIZE * HUMON_COUNT > MAX_MEMORY) { 71 throw new SkippedException("Initial heap size is to close to max heap size."); 72 } 73 74 System.out.format("Running with %s initial heap size of %s maximum heap size. " 75 + "Will allocate humongous object of %s size %d times.%n", 76 MemoryUsagePrinter.NF.format(TOTAL_MEMORY), 77 MemoryUsagePrinter.NF.format(MAX_MEMORY), 78 MemoryUsagePrinter.NF.format(HUMON_SIZE), 79 HUMON_COUNT 80 ); 81 new TestHumongousShrinkHeap().test(); 82 } 83 84 private final void test() { 85 System.gc(); 86 MemoryUsagePrinter.printMemoryUsage("init"); 87 88 allocate(); 89 MemoryUsagePrinter.printMemoryUsage("allocated"); 90 MemoryUsage muFull = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 91 92 free(); 93 MemoryUsagePrinter.printMemoryUsage("free"); 94 MemoryUsage muFree = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 95 96 assertLessThan(muFree.getCommitted(), muFull.getCommitted(), String.format( 97 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n" 98 + "%s = %s%n%s = %s", 99 MIN_FREE_RATIO_FLAG_NAME, 100 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 101 .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), 102 MAX_FREE_RATIO_FLAG_NAME, 103 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 104 .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() 105 )); 106 } 107 108 private void allocate() { 109 110 for (int i = 0; i < LISTS_COUNT; i++) { 111 List<byte[]> stuff = new ArrayList(); 112 allocateList(stuff, HUMON_COUNT, HUMON_SIZE); 113 MemoryUsagePrinter.printMemoryUsage("allocate #" + (i+1)); 114 garbage.add(stuff); 115 } 116 } 117 118 private void free() { 119 // do not free last one list 120 garbage.subList(0, garbage.size() - 1).clear(); 121 122 // do not free last one element from last list 123 List stuff = garbage.get(garbage.size() - 1); 124 stuff.subList(0, stuff.size() - 1).clear(); 125 System.gc(); 126 } 127 128 private static void allocateList(List garbage, int count, int size) { 129 for (int i = 0; i < count; i++) { 130 garbage.add(new byte[size]); 131 } 132 } 133 } 134 135 /** 136 * Prints memory usage to standard output 137 */ 138 class MemoryUsagePrinter { 139 140 public static final NumberFormat NF = Helpers.numberFormatter(); 141 142 public static void printMemoryUsage(String label) { 143 MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 144 float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted(); 145 System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n", 146 label, 147 NF.format(memusage.getInit()), 148 NF.format(memusage.getUsed()), 149 NF.format(memusage.getCommitted()), 150 freeratio * 100 151 ); 152 } 153 }