| /* |
| * Copyright (c) 2015, 2017, 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. |
| */ |
| package utils; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * This is an class used to provoke GC and perform other GC-related |
| * procedures |
| * |
| */ |
| public class GcProvoker{ |
| |
| // Uses fixed small objects to avoid Humongous objects allocation in G1 |
| private static final int MEMORY_CHUNK = 2048; |
| |
| private final Runtime runtime; |
| |
| private List<Object> allocateHeap(float targetUsage) { |
| long maxMemory = runtime.maxMemory(); |
| List<Object> list = new ArrayList<>(); |
| long used = 0; |
| long target = (long) (maxMemory * targetUsage); |
| while (used < target) { |
| try { |
| list.add(new byte[MEMORY_CHUNK]); |
| used += MEMORY_CHUNK; |
| } catch (OutOfMemoryError e) { |
| list = null; |
| throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory."); |
| } |
| } |
| return list; |
| } |
| |
| /** |
| * This method provokes a GC |
| */ |
| public void provokeGc() { |
| for (int i = 0; i < 3; i++) { |
| long edenSize = Pools.getEdenCommittedSize(); |
| long heapSize = Pools.getHeapCommittedSize(); |
| float targetPercent = ((float) edenSize) / (heapSize); |
| if ((targetPercent < 0) || (targetPercent > 1.0)) { |
| throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")"); |
| } |
| allocateHeap(targetPercent); |
| allocateHeap(targetPercent); |
| System.gc(); |
| } |
| } |
| |
| public GcProvoker() { |
| runtime = Runtime.getRuntime(); |
| } |
| } |