1 /* 2 * Copyright (c) 2014, 2016, 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 /** 25 * @test TestShrinkDefragmentedHeap 26 * @bug 8038423 8129590 27 * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects 28 * 1. allocate small objects mixed with humongous ones 29 * "ssssHssssHssssHssssHssssHssssHssssH" 30 * 2. release all allocated object except the last humongous one 31 * "..................................H" 32 * 3. invoke gc and check that memory returned to the system (amount of committed memory got down) 33 * 34 * @library /test/lib / 35 * @modules java.base/jdk.internal.misc 36 * java.management/sun.management 37 */ 38 import java.lang.management.ManagementFactory; 39 import java.lang.management.MemoryUsage; 40 import java.util.ArrayList; 41 import java.util.List; 42 import java.text.NumberFormat; 43 import static jdk.test.lib.Asserts.*; 44 import jdk.test.lib.process.OutputAnalyzer; 45 import jdk.test.lib.process.ProcessTools; 46 import com.sun.management.HotSpotDiagnosticMXBean; 47 import gc.testlibrary.Helpers; 48 49 public class TestShrinkDefragmentedHeap { 50 // Since we store all the small objects, they become old and old regions are also allocated at the bottom of the heap 51 // together with humongous regions. So if there are a lot of old regions in the lower part of the heap, 52 // the humongous regions will be allocated in the upper part of the heap anyway. 53 // To avoid this the Eden needs to be big enough to fit all the small objects. 54 private static final int INITIAL_HEAP_SIZE = 200 * 1024 * 1024; 55 private static final int MINIMAL_YOUNG_SIZE = 190 * 1024 * 1024; 56 private static final int MAXIMUM_HEAP_SIZE = 256 * 1024 * 1024; 57 private static final int REGION_SIZE = 1 * 1024 * 1024; 58 main(String[] args)59 public static void main(String[] args) throws Exception, Throwable { 60 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( 61 "-XX:InitialHeapSize=" + INITIAL_HEAP_SIZE, 62 "-Xmn" + MINIMAL_YOUNG_SIZE, 63 "-Xmx" + MAXIMUM_HEAP_SIZE, 64 "-XX:MinHeapFreeRatio=10", 65 "-XX:MaxHeapFreeRatio=11", 66 "-XX:+UseG1GC", 67 "-XX:G1HeapRegionSize=" + REGION_SIZE, 68 "-XX:-ExplicitGCInvokesConcurrent", 69 "-verbose:gc", 70 GCTest.class.getName() 71 ); 72 73 OutputAnalyzer output = ProcessTools.executeProcess(pb); 74 output.shouldHaveExitValue(0); 75 } 76 77 static class GCTest { 78 79 private static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; 80 private static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; 81 private static final String NEW_SIZE_FLAG_NAME = "NewSize"; 82 83 private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>(); 84 85 private static final int SMALL_OBJS_SIZE = 10 * 1024; // 10kB 86 private static final int SMALL_OBJS_COUNT = MINIMAL_YOUNG_SIZE / (SMALL_OBJS_SIZE-1); 87 private static final int ALLOCATE_COUNT = 3; 88 // try to put all humongous object into gap between min young size and initial heap size 89 // to avoid implicit GCs 90 private static final int HUMONG_OBJS_SIZE = (int) Math.max( 91 (INITIAL_HEAP_SIZE - MINIMAL_YOUNG_SIZE) / ALLOCATE_COUNT / 4, 92 REGION_SIZE * 1.1 93 ); 94 95 private static final long initialHeapSize = getHeapMemoryUsage().getUsed(); 96 main(String[] args)97 public static void main(String[] args) throws InterruptedException { 98 new GCTest().test(); 99 } 100 test()101 private void test() throws InterruptedException { 102 MemoryUsagePrinter.printMemoryUsage("init"); 103 104 allocate(); 105 System.gc(); 106 MemoryUsage muFull = getHeapMemoryUsage(); 107 MemoryUsagePrinter.printMemoryUsage("allocated"); 108 109 free(); 110 //Thread.sleep(1000); // sleep before measures due lags in JMX 111 MemoryUsage muFree = getHeapMemoryUsage(); 112 MemoryUsagePrinter.printMemoryUsage("free"); 113 114 assertLessThan(muFree.getCommitted(), muFull.getCommitted(), prepareMessageCommittedIsNotLess() ); 115 } 116 allocate()117 private void allocate() { 118 System.out.format("Will allocate objects of small size = %s and humongous size = %s", 119 MemoryUsagePrinter.NF.format(SMALL_OBJS_SIZE), 120 MemoryUsagePrinter.NF.format(HUMONG_OBJS_SIZE) 121 ); 122 123 for (int i = 0; i < ALLOCATE_COUNT; i++) { 124 ArrayList<byte[]> stuff = new ArrayList<>(); 125 allocateList(stuff, SMALL_OBJS_COUNT / ALLOCATE_COUNT, SMALL_OBJS_SIZE); 126 garbage.add(stuff); 127 128 ArrayList<byte[]> humongousStuff = new ArrayList<>(); 129 allocateList(humongousStuff, 4, HUMONG_OBJS_SIZE); 130 garbage.add(humongousStuff); 131 } 132 } 133 free()134 private void free() { 135 // do not free last one list 136 garbage.subList(0, garbage.size() - 1).clear(); 137 138 // do not free last one element from last list 139 ArrayList stuff = garbage.get(garbage.size() - 1); 140 if (stuff.size() > 1) { 141 stuff.subList(0, stuff.size() - 1).clear(); 142 } 143 System.gc(); 144 } 145 prepareMessageCommittedIsNotLess()146 private String prepareMessageCommittedIsNotLess() { 147 return String.format( 148 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n" 149 + "%s = %s%n%s = %s", 150 MIN_FREE_RATIO_FLAG_NAME, 151 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 152 .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), 153 MAX_FREE_RATIO_FLAG_NAME, 154 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class) 155 .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() 156 ); 157 } 158 allocateList(List garbage, int count, int size)159 private static void allocateList(List garbage, int count, int size) { 160 for (int i = 0; i < count; i++) { 161 garbage.add(new byte[size]); 162 } 163 } 164 } 165 getHeapMemoryUsage()166 static MemoryUsage getHeapMemoryUsage() { 167 return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 168 } 169 170 /** 171 * Prints memory usage to standard output 172 */ 173 static class MemoryUsagePrinter { 174 175 public static final NumberFormat NF = Helpers.numberFormatter(); 176 printMemoryUsage(String label)177 public static void printMemoryUsage(String label) { 178 MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); 179 float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted(); 180 System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n", 181 label, 182 NF.format(memusage.getInit()), 183 NF.format(memusage.getUsed()), 184 NF.format(memusage.getCommitted()), 185 freeratio * 100 186 ); 187 } 188 } 189 } 190