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 */
23package utils;
24
25import java.lang.management.ManagementFactory;
26import java.lang.management.MemoryMXBean;
27import java.lang.management.MemoryPoolMXBean;
28import java.lang.management.MemoryUsage;
29import java.util.ArrayList;
30import java.util.List;
31
32/**
33 * This is an class used to allocate specified amount of metaspace and heap.
34 */
35public 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     */
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     */
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
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
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
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     */
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