1 /*
2  * Copyright (c) 2017, 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.MemoryMXBean;
27 import java.lang.management.MemoryPoolMXBean;
28 import java.lang.management.MemoryUsage;
29 import java.util.ArrayList;
30 import java.util.List;
31 
32 /**
33  * This is an class used to allocate specified amount of metaspace and heap.
34  */
35 public class GarbageProducer {
36 
37     // Uses fixed small objects to avoid Humongous objects allocation with G1 GC.
38     private static final int MEMORY_CHUNK = 2048;
39 
40     public static List<Object> allocatedMetaspace;
41     public static List<Object> allocatedMemory;
42 
43     private final MemoryMXBean memoryMXBean;
44     private final float targetMemoryUsagePercent;
45     private final long targetMemoryUsage;
46 
47     /**
48      * @param targetMemoryUsagePercent how many percent of metaspace and heap to
49      * allocate
50      */
GarbageProducer(float targetMemoryUsagePercent)51     public GarbageProducer(float targetMemoryUsagePercent) {
52         memoryMXBean = ManagementFactory.getMemoryMXBean();
53         this.targetMemoryUsagePercent = targetMemoryUsagePercent;
54         targetMemoryUsage = (long) (memoryMXBean.getHeapMemoryUsage().getMax() * targetMemoryUsagePercent);
55     }
56 
57     /**
58      * Allocates heap and metaspace upon exit targetMemoryUsagePercent percents
59      * of heap and metaspace have been consumed.
60      */
allocateMetaspaceAndHeap()61     public void allocateMetaspaceAndHeap() {
62         // Metaspace should be filled before Java Heap to prevent unexpected OOME
63         // in the Java Heap while filling Metaspace
64         allocatedMetaspace = eatMetaspace(targetMemoryUsagePercent);
65         allocatedMemory = allocateGarbage(targetMemoryUsage);
66     }
67 
eatMetaspace(float targetUsage)68     private List<Object> eatMetaspace(float targetUsage) {
69         List<Object> list = new ArrayList<>();
70         MemoryPoolMXBean metaspacePool = getMatchedMemoryPool(".*Metaspace.*");
71         float currentUsage;
72         GeneratedClassProducer gp = new GeneratedClassProducer();
73         do {
74             try {
75                 list.add(gp.create(0));
76             } catch (OutOfMemoryError oome) {
77                 list = null;
78                 throw new RuntimeException("Unexpected OOME '" + oome.getMessage() + "' while eating " + targetUsage + " of Metaspace.");
79             }
80             MemoryUsage memoryUsage = metaspacePool.getUsage();
81             currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax());
82         } while (currentUsage < targetUsage);
83         return list;
84     }
85 
getMatchedMemoryPool(String patternPoolName)86     private MemoryPoolMXBean getMatchedMemoryPool(String patternPoolName) {
87         return ManagementFactory.getMemoryPoolMXBeans().stream()
88                 .filter(bean -> bean.getName().matches(patternPoolName))
89                 .findFirst()
90                 .orElseThrow(() -> new RuntimeException("Cannot find '" + patternPoolName + "' memory pool."));
91     }
92 
allocateGarbage(long targetMemoryUsage)93     private List<Object> allocateGarbage(long targetMemoryUsage) {
94         List<Object> list = new ArrayList<>();
95         do {
96             try {
97                 list.add(new byte[MEMORY_CHUNK]);
98             } catch (OutOfMemoryError e) {
99                 list = null;
100                 throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "'");
101             }
102         } while (memoryMXBean.getHeapMemoryUsage().getUsed() < targetMemoryUsage);
103         return list;
104     }
105 
106     /**
107      * Returns allocation rate for old gen based on appropriate MemoryPoolMXBean
108      * memory usage.
109      *
110      * @return allocation rate
111      */
getOldGenAllocationRatio()112     public float getOldGenAllocationRatio() {
113         MemoryPoolMXBean oldGenBean = getMatchedMemoryPool(".*Old.*|.*Tenured.*");
114         MemoryUsage usage = oldGenBean.getUsage();
115         System.out.format("Memory usage for %1s.\n", oldGenBean.getName());
116         System.out.format("Used: %1d\n", usage.getUsed());
117         System.out.format("Commited: %1d\n", usage.getCommitted());
118         System.out.format("Max: %1d\n", usage.getMax());
119         return ((float) usage.getUsed()) / usage.getCommitted();
120     }
121 }
122