1 /*
2 * Copyright (c) 2014, 2019, 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
24 package gc.g1;
25
26 /**
27 * @test TestShrinkDefragmentedHeap
28 * @bug 8038423 8129590
29 * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects
30 * 1. allocate small objects mixed with humongous ones
31 * "ssssHssssHssssHssssHssssHssssHssssH"
32 * 2. release all allocated object except the last humongous one
33 * "..................................H"
34 * 3. invoke gc and check that memory returned to the system (amount of committed memory got down)
35 *
36 * @library /test/lib /
37 * @modules java.base/jdk.internal.misc
38 * java.management/sun.management
39 * @run main gc.g1.TestShrinkDefragmentedHeap
40 */
41 import java.lang.management.ManagementFactory;
42 import java.lang.management.MemoryUsage;
43 import java.util.ArrayList;
44 import java.util.List;
45 import java.text.NumberFormat;
46 import static jdk.test.lib.Asserts.*;
47 import jdk.test.lib.process.OutputAnalyzer;
48 import jdk.test.lib.process.ProcessTools;
49 import com.sun.management.HotSpotDiagnosticMXBean;
50 import gc.testlibrary.Helpers;
51
52 public class TestShrinkDefragmentedHeap {
53 // Since we store all the small objects, they become old and old regions are also allocated at the bottom of the heap
54 // together with humongous regions. So if there are a lot of old regions in the lower part of the heap,
55 // the humongous regions will be allocated in the upper part of the heap anyway.
56 // To avoid this the Eden needs to be big enough to fit all the small objects.
57 private static final int INITIAL_HEAP_SIZE = 200 * 1024 * 1024;
58 private static final int MINIMAL_YOUNG_SIZE = 190 * 1024 * 1024;
59 private static final int MAXIMUM_HEAP_SIZE = 256 * 1024 * 1024;
60 private static final int REGION_SIZE = 1 * 1024 * 1024;
61
62 public static void main(String[] args) throws Exception, Throwable {
63 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
64 "-XX:InitialHeapSize=" + INITIAL_HEAP_SIZE,
65 "-Xmn" + MINIMAL_YOUNG_SIZE,
66 "-Xmx" + MAXIMUM_HEAP_SIZE,
67 "-XX:MinHeapFreeRatio=10",
68 "-XX:MaxHeapFreeRatio=11",
69 "-XX:+UseG1GC",
70 "-XX:G1HeapRegionSize=" + REGION_SIZE,
71 "-XX:-ExplicitGCInvokesConcurrent",
72 "-verbose:gc",
73 GCTest.class.getName()
74 );
75
76 OutputAnalyzer output = ProcessTools.executeProcess(pb);
77 output.shouldHaveExitValue(0);
78 }
79
80 static class GCTest {
81
82 private static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio";
83 private static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio";
84 private static final String NEW_SIZE_FLAG_NAME = "NewSize";
85
86 private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>();
87
88 private static final int SMALL_OBJS_SIZE = 10 * 1024; // 10kB
89 private static final int SMALL_OBJS_COUNT = MINIMAL_YOUNG_SIZE / (SMALL_OBJS_SIZE-1);
90 private static final int ALLOCATE_COUNT = 3;
91 // try to put all humongous object into gap between min young size and initial heap size
92 // to avoid implicit GCs
93 private static final int HUMONG_OBJS_SIZE = (int) Math.max(
94 (INITIAL_HEAP_SIZE - MINIMAL_YOUNG_SIZE) / ALLOCATE_COUNT / 4,
95 REGION_SIZE * 1.1
96 );
97
98 private static final long initialHeapSize = getHeapMemoryUsage().getUsed();
99
100 public static void main(String[] args) throws InterruptedException {
101 new GCTest().test();
102 }
103
104 private void test() throws InterruptedException {
105 MemoryUsagePrinter.printMemoryUsage("init");
106
107 allocate();
108 System.gc();
109 MemoryUsage muFull = getHeapMemoryUsage();
110 MemoryUsagePrinter.printMemoryUsage("allocated");
111
112 free();
113 //Thread.sleep(1000); // sleep before measures due lags in JMX
114 MemoryUsage muFree = getHeapMemoryUsage();
115 MemoryUsagePrinter.printMemoryUsage("free");
116
117 assertLessThan(muFree.getCommitted(), muFull.getCommitted(), prepareMessageCommittedIsNotLess() );
118 }
119
120 private void allocate() {
121 System.out.format("Will allocate objects of small size = %s and humongous size = %s",
122 MemoryUsagePrinter.NF.format(SMALL_OBJS_SIZE),
123 MemoryUsagePrinter.NF.format(HUMONG_OBJS_SIZE)
124 );
125
126 for (int i = 0; i < ALLOCATE_COUNT; i++) {
127 ArrayList<byte[]> stuff = new ArrayList<>();
128 allocateList(stuff, SMALL_OBJS_COUNT / ALLOCATE_COUNT, SMALL_OBJS_SIZE);
129 garbage.add(stuff);
130
131 ArrayList<byte[]> humongousStuff = new ArrayList<>();
132 allocateList(humongousStuff, 4, HUMONG_OBJS_SIZE);
133 garbage.add(humongousStuff);
134 }
135 }
136
137 private void free() {
138 // do not free last one list
139 garbage.subList(0, garbage.size() - 1).clear();
140
141 // do not free last one element from last list
142 ArrayList<byte[]> stuff = garbage.get(garbage.size() - 1);
143 if (stuff.size() > 1) {
144 stuff.subList(0, stuff.size() - 1).clear();
145 }
146 System.gc();
147 }
148
149 private String prepareMessageCommittedIsNotLess() {
150 return String.format(
151 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n"
152 + "%s = %s%n%s = %s",
153 MIN_FREE_RATIO_FLAG_NAME,
154 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)
155 .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(),
156 MAX_FREE_RATIO_FLAG_NAME,
157 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)
158 .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue()
159 );
160 }
161
162 private static void allocateList(List<byte[]> garbage, int count, int size) {
163 for (int i = 0; i < count; i++) {
164 garbage.add(new byte[size]);
165 }
166 }
167 }
168
169 static MemoryUsage getHeapMemoryUsage() {
170 return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
171 }
172
173 /**
174 * Prints memory usage to standard output
175 */
176 static class MemoryUsagePrinter {
177
178 public static final NumberFormat NF = Helpers.numberFormatter();
179
180 public static void printMemoryUsage(String label) {
181 MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
182 float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted();
183 System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n",
184 label,
185 NF.format(memusage.getInit()),
186 NF.format(memusage.getUsed()),
187 NF.format(memusage.getCommitted()),
188 freeratio * 100
189 );
190 }
191 }
192 }