1 /* 2 * Copyright (c) 2019, 2020, 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.z; 25 26 /* 27 * @test TestUncommit 28 * @requires vm.gc.Z & !vm.graal.enabled 29 * @summary Test ZGC uncommit unused memory 30 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=10 gc.z.TestUncommit true 2 31 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms512M -Xmx512M -XX:ZUncommitDelay=10 gc.z.TestUncommit false 1 32 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=10 -XX:-ZUncommit gc.z.TestUncommit false 1 33 */ 34 35 import java.util.ArrayList; 36 37 public class TestUncommit { 38 private static final int delay = 10; // seconds 39 private static final int allocSize = 200 * 1024 * 1024; // 200M 40 private static final int smallObjectSize = 4 * 1024; // 4K 41 private static final int mediumObjectSize = 2 * 1024 * 1024; // 2M 42 private static final int largeObjectSize = allocSize; 43 44 private static volatile ArrayList<byte[]> keepAlive; 45 46 private static long capacity() { 47 return Runtime.getRuntime().totalMemory(); 48 } 49 50 private static void allocate(int objectSize) { 51 keepAlive = new ArrayList<>(); 52 for (int i = 0; i < allocSize; i+= objectSize) { 53 keepAlive.add(new byte[objectSize]); 54 } 55 } 56 57 private static void reclaim() { 58 keepAlive = null; 59 System.gc(); 60 } 61 62 private static void test(boolean enabled, int objectSize) throws Exception { 63 final var beforeAlloc = capacity(); 64 65 // Allocate memory 66 allocate(objectSize); 67 68 final var afterAlloc = capacity(); 69 70 // Reclaim memory 71 reclaim(); 72 73 // Wait shorter than the uncommit delay 74 Thread.sleep(delay * 1000 / 2); 75 76 final var beforeUncommit = capacity(); 77 78 // Wait longer than the uncommit delay 79 Thread.sleep(delay * 1000); 80 81 final var afterUncommit = capacity(); 82 83 System.out.println(" Uncommit Enabled: " + enabled); 84 System.out.println(" Uncommit Delay: " + delay); 85 System.out.println(" Object Size: " + objectSize); 86 System.out.println(" Alloc Size: " + allocSize); 87 System.out.println(" Before Alloc: " + beforeAlloc); 88 System.out.println(" After Alloc: " + afterAlloc); 89 System.out.println(" Before Uncommit: " + beforeUncommit); 90 System.out.println(" After Uncommit: " + afterUncommit); 91 System.out.println(); 92 93 // Verify 94 if (enabled) { 95 if (beforeUncommit == beforeAlloc) { 96 throw new Exception("Uncommitted too fast"); 97 } 98 99 if (afterUncommit >= afterAlloc) { 100 throw new Exception("Uncommitted too slow"); 101 } 102 103 if (afterUncommit < beforeAlloc) { 104 throw new Exception("Uncommitted too much"); 105 } 106 107 if (afterUncommit > beforeAlloc) { 108 throw new Exception("Uncommitted too little"); 109 } 110 } else { 111 if (afterAlloc > beforeUncommit || 112 afterAlloc > afterUncommit) { 113 throw new Exception("Should not uncommit"); 114 } 115 } 116 } 117 118 public static void main(String[] args) throws Exception { 119 final boolean enabled = Boolean.parseBoolean(args[0]); 120 final int iterations = Integer.parseInt(args[1]); 121 122 for (int i = 0; i < iterations; i++) { 123 System.out.println("Iteration " + i); 124 test(enabled, smallObjectSize); 125 test(enabled, mediumObjectSize); 126 test(enabled, largeObjectSize); 127 } 128 } 129 }