1 /* 2 * Copyright (c) 2015, 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 package utils; 24 25 import java.lang.management.ManagementFactory; 26 import java.lang.management.MemoryPoolMXBean; 27 import java.lang.management.MemoryUsage; 28 import java.util.ArrayList; 29 import java.util.List; 30 31 /** 32 * 33 * Utilities to provoke GC in various ways 34 */ 35 public class GcProvokerImpl implements GcProvoker { 36 37 private static List<Object> eatenMetaspace; 38 private static List<Object> eatenMemory; 39 40 static List<Object> eatHeapMemory(float targetUsage) { 41 long maxMemory = Runtime.getRuntime().maxMemory(); 42 // uses fixed small objects to avoid Humongous objects allocation in G1 43 int memoryChunk = 2048; 44 List<Object> list = new ArrayList<>(); 45 float used = 0; 46 while (used < targetUsage * maxMemory) { 47 try { 48 list.add(new byte[memoryChunk]); 49 used += memoryChunk; 50 } catch (OutOfMemoryError e) { 51 list = null; 52 throw new RuntimeException("Unexpected OOME while eating " + targetUsage + " of heap memory."); 53 } 54 } 55 return list; 56 } 57 58 @Override 59 public void provokeGc() { 60 for (int i = 0; i < 3; i++) { 61 long edenSize = Pools.getEdenCommittedSize(); 62 long heapSize = Pools.getHeapCommittedSize(); 63 float targetPercent = ((float) edenSize) / (heapSize); 64 if ((targetPercent < 0) || (targetPercent > 1.0)) { 65 throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")"); 66 } 67 eatHeapMemory(targetPercent); 68 eatHeapMemory(targetPercent); 69 System.gc(); 70 } 71 } 72 73 @Override 74 public void eatMetaspaceAndHeap(float targetMemoryUsagePercent) { 75 eatenMemory = eatHeapMemory(targetMemoryUsagePercent); 76 eatenMetaspace = eatMetaspace(targetMemoryUsagePercent); 77 } 78 79 private static List<Object> eatMetaspace(float targetUsage) { 80 List<Object> list = new ArrayList<>(); 81 final String metaspacePoolName = "Metaspace"; 82 MemoryPoolMXBean metaspacePool = null; 83 for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) { 84 if (pool.getName().contains(metaspacePoolName)) { 85 metaspacePool = pool; 86 break; 87 } 88 } 89 if (metaspacePool == null) { 90 throw new RuntimeException("MXBean for Metaspace pool wasn't found"); 91 } 92 float currentUsage; 93 GeneratedClassProducer gp = new GeneratedClassProducer(); 94 do { 95 try { 96 list.add(gp.create(0)); 97 } catch (OutOfMemoryError oome) { 98 list = null; 99 throw new RuntimeException("Unexpected OOME while eating " + targetUsage + " of Metaspace."); 100 } 101 MemoryUsage memoryUsage = metaspacePool.getUsage(); 102 currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax()); 103 } while (currentUsage < targetUsage); 104 return list; 105 } 106 107 public GcProvokerImpl() { 108 } 109 110 }