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 * This is an class used to provoke GC and perform other GC-related 33 * procedures 34 * 35 */ 36 public class GcProvoker{ 37 38 // Uses fixed small objects to avoid Humongous objects allocation in G1 39 public static final int MEMORY_CHUNK = 2048; 40 public static final float ALLOCATION_TOLERANCE = 0.05f; 41 42 public static List<Object> allocatedMetaspace; 43 public static List<Object> allocatedMemory; 44 45 private final Runtime runtime; 46 47 private List<Object> allocateHeap(float targetUsage) { 48 long maxMemory = runtime.maxMemory(); 49 List<Object> list = new ArrayList<>(); 50 long used = 0; 51 long target = (long) (maxMemory * targetUsage); 52 while (used < target) { 53 try { 54 list.add(new byte[MEMORY_CHUNK]); 55 used += MEMORY_CHUNK; 56 } catch (OutOfMemoryError e) { 57 list = null; 58 throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory."); 59 } 60 } 61 return list; 62 } 63 64 private List<Object> allocateAvailableHeap(float targetUsage) { 65 // Calculates size of free memory after allocation with small tolerance. 66 long minFreeMemory = (long) ((1.0 - (targetUsage + ALLOCATION_TOLERANCE)) * runtime.maxMemory()); 67 List<Object> list = new ArrayList<>(); 68 do { 69 try { 70 list.add(new byte[MEMORY_CHUNK]); 71 } catch (OutOfMemoryError e) { 72 list = null; 73 throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory."); 74 } 75 } while (runtime.freeMemory() > minFreeMemory); 76 return list; 77 } 78 79 /** 80 * This method provokes a GC 81 */ 82 public void provokeGc() { 83 for (int i = 0; i < 3; i++) { 84 long edenSize = Pools.getEdenCommittedSize(); 85 long heapSize = Pools.getHeapCommittedSize(); 86 float targetPercent = ((float) edenSize) / (heapSize); 87 if ((targetPercent < 0) || (targetPercent > 1.0)) { 88 throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")"); 89 } 90 allocateHeap(targetPercent); 91 allocateHeap(targetPercent); 92 System.gc(); 93 } 94 } 95 96 /** 97 * Allocates heap and metaspace upon exit not less than targetMemoryUsagePercent percents 98 * of heap and metaspace have been consumed. 99 * 100 * @param targetMemoryUsagePercent how many percent of heap and metaspace to 101 * allocate 102 */ 103 104 public void allocateMetaspaceAndHeap(float targetMemoryUsagePercent) { 105 // Metaspace should be filled before Java Heap to prevent unexpected OOME 106 // in the Java Heap while filling Metaspace 107 allocatedMetaspace = eatMetaspace(targetMemoryUsagePercent); 108 allocatedMemory = allocateHeap(targetMemoryUsagePercent); 109 } 110 111 /** 112 * Allocates heap and metaspace upon exit targetMemoryUsagePercent percents 113 * of heap and metaspace have been consumed. 114 * 115 * @param targetMemoryUsagePercent how many percent of heap and metaspace to 116 * allocate 117 */ 118 public void allocateAvailableMetaspaceAndHeap(float targetMemoryUsagePercent) { 119 // Metaspace should be filled before Java Heap to prevent unexpected OOME 120 // in the Java Heap while filling Metaspace 121 allocatedMetaspace = eatMetaspace(targetMemoryUsagePercent); 122 allocatedMemory = allocateAvailableHeap(targetMemoryUsagePercent); 123 } 124 125 private List<Object> eatMetaspace(float targetUsage) { 126 List<Object> list = new ArrayList<>(); 127 final String metaspacePoolName = "Metaspace"; 128 MemoryPoolMXBean metaspacePool = null; 129 for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) { 130 if (pool.getName().contains(metaspacePoolName)) { 131 metaspacePool = pool; 132 break; 133 } 134 } 135 if (metaspacePool == null) { 136 throw new RuntimeException("MXBean for Metaspace pool wasn't found"); 137 } 138 float currentUsage; 139 GeneratedClassProducer gp = new GeneratedClassProducer(); 140 do { 141 try { 142 list.add(gp.create(0)); 143 } catch (OutOfMemoryError oome) { 144 list = null; 145 throw new RuntimeException("Unexpected OOME '" + oome.getMessage() + "' while eating " + targetUsage + " of Metaspace."); 146 } 147 MemoryUsage memoryUsage = metaspacePool.getUsage(); 148 currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax()); 149 } while (currentUsage < targetUsage); 150 return list; 151 } 152 153 public GcProvoker() { 154 runtime = Runtime.getRuntime(); 155 } 156 157 }