| /* |
| * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| import java.util.LinkedList; |
| import java.util.concurrent.Callable; |
| |
| /** |
| * Helper class which allocates memory. |
| * |
| * Typical usage: |
| * <pre> |
| * {@code |
| * AllocationHelper allocator = new AllocationHelper(MAX_ITERATIONS, ARRAY_LENGTH, CHUNK_SIZE, |
| * () -> (verifier())); |
| * // Allocate byte[CHUNK_SIZE] ARRAY_LENGTH times. Total allocated bytes will be CHUNK_SIZE * ARRAY_LENGTH + refs length. |
| * // Then invoke verifier and iterate MAX_ITERATIONS times. |
| * allocator.allocateMemoryAndVerify(); |
| * } |
| * </pre> |
| */ |
| public final class AllocationHelper { |
| |
| private final int arrayLength; |
| private final int maxIterations; |
| private final int chunkSize; |
| |
| // garbageStorage is used to store link to garbage to prevent optimization. |
| private static Object garbageStorage; |
| private byte garbage[][]; |
| private final Callable<?> verifierInstance; |
| |
| /** |
| * Create an AllocationHelper with specified iteration count, array length, chunk size and verifier. |
| * |
| * @param maxIterations |
| * @param arrayLength |
| * @param chunkSize |
| * @param verifier - Callable instance which will be invoked after all allocation cycle. Can be null; |
| */ |
| public AllocationHelper(int maxIterations, int arrayLength, int chunkSize, Callable<?> verifier) { |
| if ((arrayLength <= 0) || (maxIterations <= 0) || (chunkSize <= 0)) { |
| throw new IllegalArgumentException("maxIterations, arrayLength and chunkSize should be greater then 0."); |
| } |
| this.arrayLength = arrayLength; |
| this.maxIterations = maxIterations; |
| this.chunkSize = chunkSize; |
| verifierInstance = verifier; |
| garbage = new byte[this.arrayLength][]; |
| garbageStorage = garbage; |
| } |
| |
| private void allocateMemoryOneIteration() { |
| for (int j = 0; j < arrayLength; j++) { |
| garbage[j] = new byte[chunkSize]; |
| } |
| } |
| |
| /** |
| * Allocate memory and invoke Verifier during all iteration. |
| * |
| * @throws java.lang.Exception |
| */ |
| public void allocateMemoryAndVerify() throws Exception { |
| for (int i = 0; i < maxIterations; i++) { |
| allocateMemoryOneIteration(); |
| if (verifierInstance != null) { |
| verifierInstance.call(); |
| } |
| } |
| } |
| |
| /** |
| * The same as allocateMemoryAndVerify() but hides OOME |
| * |
| * @throws Exception |
| */ |
| public void allocateMemoryAndVerifyNoOOME() throws Exception { |
| try { |
| allocateMemoryAndVerify(); |
| } catch (OutOfMemoryError e) { |
| // exit on OOME |
| } |
| } |
| |
| /** |
| * Release link to allocated garbage to make it available for further GC |
| */ |
| public void release() { |
| if (garbage != null) { |
| garbage = null; |
| garbageStorage = null; |
| } |
| } |
| } |