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 TestShrinkDefragmentedHeap 28 * @bug 8038423 8129590 29 * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects 30 * 1. allocate small objects mixed with humongous ones 31 * "ssssHssssHssssHssssHssssHssssHssssH" 32 * 2. release all allocated object except the last humongous one 33 * "..................................H" 34 * 3. invoke gc and check that memory returned to the system (amount of committed memory got down) 35 * 36 * @library /test/lib / 37 * @requires vm.gc.G1 38 * @modules java.base/jdk.internal.misc 39 * java.management/sun.management 40 * @run main gc.g1.TestShrinkDefragmentedHeap 41 */ 42 import java.lang.management.ManagementFactory; 43 import java.lang.management.MemoryUsage; 44 import java.util.ArrayList; 45 import java.util.List; 46 import java.text.NumberFormat; 47 import static jdk.test.lib.Asserts.*; 48 import jdk.test.lib.process.OutputAnalyzer; 49 import jdk.test.lib.process.ProcessTools; 50 import com.sun.management.HotSpotDiagnosticMXBean; 51 import gc.testlibrary.Helpers; 52 53 public class TestShrinkDefragmentedHeap { 54 // Since we store all the small objects, they become old and old regions are also allocated at the bottom of the heap 55 // together with humongous regions. So if there are a lot of old regions in the lower part of the heap, 56 // the humongous regions will be allocated in the upper part of the heap anyway. 57 // To avoid this the Eden needs to be big enough to fit all the small objects. 58 private static final int INITIAL_HEAP_SIZE = 200 * 1024 * 1024; 59 private static final int MINIMAL_YOUNG_SIZE = 190 * 1024 * 1024; 60 private static final int MAXIMUM_HEAP_SIZE = 256 * 1024 * 1024; 61 private static final int REGION_SIZE = 1 * 1024 * 1024; 62 main(String[] args)63 public static void main(String[] args) throws Exception, Throwable { 64 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( 65 "-XX:InitialHeapSize=" + INITIAL_HEAP_SIZE, 66 "-Xmn" + MINIMAL_YOUNG_SIZE, 67 "-Xmx" + MAXIMUM_HEAP_SIZE, 68 "-XX:MinHeapFreeRatio=10", 69 "-XX:MaxHeapFreeRatio=11", 70 "-XX:+UseG1GC", 71 "-XX:G1HeapRegionSize=" + REGION_SIZE, 72 "-XX:-ExplicitGCInvokesConcurrent", 73 "-verbose:gc", 74 GCTest.class.getName() 75 ); 76 77 OutputAnalyzer output = ProcessTools.executeProcess(pb); 78 output.shouldHaveExitValue(0); 79 } 80 81 static class GCTest { 82 83 private static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; 84 private static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; 85 private static final String NEW_SIZE_FLAG_NAME = "NewSize"; 86 87 private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>(); 88 89 private static final int SMALL_OBJS_SIZE = 10 * 1024; // 10kB 90 private static final int SMALL_OBJS_COUNT = MINIMAL_YOUNG_SIZE / (SMALL_OBJS_SIZE-1); 91 private static final int ALLOCATE_COUNT = 3; 92 // try to put all humongous object into gap between min young size and initial heap size 93 // to avoid implicit GCs 94 private static final int HUMONG_OBJS_SIZE = (int) Math.max( 95 (INITIAL_HEAP_SIZE - MINIMAL_YOUNG_SIZE) / ALLOCATE_COUNT / 4, 96 REGION_SIZE * 1.1 97 ); 98 99 private static final long initialHeapSize = getHeapMemoryUsage().getUsed(); 100 main(String[] args)101 public static void main(String[] args) throws InterruptedException { 102 new GCTest().test(); 103 } 104 test()105 private void test() throws InterruptedException { 106 MemoryUsagePrinter.printMemoryUsage("init"); 107 108 allocate(); 109 System.gc(); 110 MemoryUsage muFull = getHeapMemoryUsage(); 111 MemoryUsagePrinter.printMemoryUsage("allocated"); 112 113 free(); 114 //Thread.sleep(1000); // sleep before measures due lags in JMX 115 MemoryUsage muFree = getHeapMemoryUsage(); 116 MemoryUsagePrinter.printMemoryUsage("free"); 117 118 assertLessThan(muFree.getCommitted(), muFull.getCommitted(), prepareMessageCommittedIsNotLess() ); 119 } 120 allocate()121 private void allocate() { 122 System.out.format("Will allocate objects of small size = %s and humongous size = %s", 123 MemoryUsagePrinter.NF.format(SMALL_OBJS_SIZE), 124 MemoryUsagePrinter.NF.format(HUMONG_OBJS_SIZE) 125 ); 126 127 for (int i = 0; i < ALLOCATE_COUNT; i++) { 128 ArrayList<byte[]> stuff = new ArrayList<>(); 129 allocateList(stuff, SMALL_OBJS_COUNT / ALLOCATE_COUNT, SMALL_OBJS_SIZE); 130 garbage.add(stuff); 131 132 ArrayList<byte[]> humongousStuff = new ArrayList<>(); 133 allocateList(humongousStuff, 4, HUMONG_OBJS_SIZE); 134 garbage.add(humongousStuff); 135 } 136 } 137 free()138 private void free() { 139 // do not free last one list 140 garbage.subList(0, garbage.size() - 1).clear(); 141 142 // do not free last one element from last list 143 ArrayList<byte[]> stuff = garbage.get(garbage.size() - 1); 144 if (stuff.size() > 1) { 145 stuff.subList(0, stuff.size() - 1).clear(); 146 } 147 System.gc(); 148 } 149 prepareMessageCommittedIsNotLess()150 private String prepareMessageCommittedIsNotLess() { 151 return String.format( 152 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n" 153 + "%s = %s%n%s = %s", 154 MIN_FREE_RATIO_FLAG_NAME, 155 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 156 .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), 157 MAX_FREE_RATIO_FLAG_NAME, 158 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 159 .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() 160 ); 161 } 162 allocateList(List<byte[]> garbage, int count, int size)163 private static void allocateList(List<byte[]> garbage, int count, int size) { 164 for (int i = 0; i < count; i++) { 165 garbage.add(new byte[size]); 166 } 167 } 168 } 169 getHeapMemoryUsage()170 static MemoryUsage getHeapMemoryUsage() { 171 return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 172 } 173 174 /** 175 * Prints memory usage to standard output 176 */ 177 static class MemoryUsagePrinter { 178 179 public static final NumberFormat NF = Helpers.numberFormatter(); 180 printMemoryUsage(String label)181 public static void printMemoryUsage(String label) { 182 MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 183 float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted(); 184 System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n", 185 label, 186 NF.format(memusage.getInit()), 187 NF.format(memusage.getUsed()), 188 NF.format(memusage.getCommitted()), 189 freeratio * 100 190 ); 191 } 192 } 193 } 194