1 /* 2 * Copyright (c) 2015, 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 import java.util.LinkedList; 25 import java.util.concurrent.Callable; 26 27 /** 28 * Helper class which allocates memory. 29 * 30 * Typical usage: 31 * <pre> 32 * {@code 33 * AllocationHelper allocator = new AllocationHelper(MAX_ITERATIONS, ARRAY_LENGTH, CHUNK_SIZE, 34 * () -> (verifier())); 35 * // Allocate byte[CHUNK_SIZE] ARRAY_LENGTH times. Total allocated bytes will be CHUNK_SIZE * ARRAY_LENGTH + refs length. 36 * // Then invoke verifier and iterate MAX_ITERATIONS times. 37 * allocator.allocateMemoryAndVerify(); 38 * } 39 * </pre> 40 */ 41 public final class AllocationHelper { 42 43 private final int arrayLength; 44 private final int maxIterations; 45 private final int chunkSize; 46 47 // garbageStorage is used to store link to garbage to prevent optimization. 48 private static Object garbageStorage; 49 private byte garbage[][]; 50 private final Callable<?> verifierInstance; 51 52 /** 53 * Create an AllocationHelper with specified iteration count, array length, chunk size and verifier. 54 * 55 * @param maxIterations 56 * @param arrayLength 57 * @param chunkSize 58 * @param verifier - Callable instance which will be invoked after all allocation cycle. Can be null; 59 */ 60 public AllocationHelper(int maxIterations, int arrayLength, int chunkSize, Callable<?> verifier) { 61 if ((arrayLength <= 0) || (maxIterations <= 0) || (chunkSize <= 0)) { 62 throw new IllegalArgumentException("maxIterations, arrayLength and chunkSize should be greater then 0."); 63 } 64 this.arrayLength = arrayLength; 65 this.maxIterations = maxIterations; 66 this.chunkSize = chunkSize; 67 verifierInstance = verifier; 68 garbage = new byte[this.arrayLength][]; 69 garbageStorage = garbage; 70 } 71 72 private void allocateMemoryOneIteration() { 73 for (int j = 0; j < arrayLength; j++) { 74 garbage[j] = new byte[chunkSize]; 75 } 76 } 77 78 /** 79 * Allocate memory and invoke Verifier during all iteration. 80 * 81 * @throws java.lang.Exception 82 */ 83 public void allocateMemoryAndVerify() throws Exception { 84 for (int i = 0; i < maxIterations; i++) { 85 allocateMemoryOneIteration(); 86 if (verifierInstance != null) { 87 verifierInstance.call(); 88 } 89 } 90 } 91 92 /** 93 * The same as allocateMemoryAndVerify() but hides OOME 94 * 95 * @throws Exception 96 */ 97 public void allocateMemoryAndVerifyNoOOME() throws Exception { 98 try { 99 allocateMemoryAndVerify(); 100 } catch (OutOfMemoryError e) { 101 // exit on OOME 102 } 103 } 104 105 /** 106 * Release link to allocated garbage to make it available for further GC 107 */ 108 public void release() { 109 if (garbage != null) { 110 garbage = null; 111 garbageStorage = null; 112 } 113 } 114 }