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
24 package gc.g1.humongousObjects;
25
26 import gc.testlibrary.Helpers;
27 import jdk.test.lib.Asserts;
28 import sun.hotspot.WhiteBox;
29
30 import java.lang.ref.Reference;
31 import java.lang.ref.ReferenceQueue;
32 import java.lang.ref.SoftReference;
33 import java.lang.ref.WeakReference;
34
35 /**
36 * @test TestObjectCollected
37 * @summary checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
38 * actual object behavior
39 * @requires vm.gc.G1
40 * @library /test/lib /
41 * @modules java.base/jdk.internal.misc
42 * @modules java.management
43 * @build sun.hotspot.WhiteBox
44 * @run driver ClassFileInstaller sun.hotspot.WhiteBox
45 * sun.hotspot.WhiteBox$WhiteBoxPermission
46 *
47 * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
48 * -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xms200m -Xmx200m -Xlog:gc
49 * -XX:InitiatingHeapOccupancyPercent=100 -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectCollected.gc.log
50 * gc.g1.humongousObjects.TestObjectCollected
51 */
52
53
54 /**
55 * Test checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
56 * actual object behavior.
57 * So if object was collected, reference.get() should return null and vice versa
58 * Since we check humongous objects after such an object is collected the region where it was allocated becomes free
59 * or/and change type to non-humongous. Two WhiteBox method were used - first returns if a region containing certain
60 * address is free and second - if a region containing certain address is humongous
61 */
62
63 public class TestObjectCollected {
64 /**
65 * Provides methods to initiate GC of requested type
66 */
67 private enum GC {
68 YOUNG_CG {
69 @Override
70 public void provoke() {
71 WHITE_BOX.youngGC();
72 }
73 },
74 FULL_GC {
75 @Override
76 public void provoke() {
77 System.gc();
78 }
79 },
80 CMC {
81 @Override
82 public void provoke() {
83 Helpers.waitTillCMCFinished(WHITE_BOX, 0);
84 WHITE_BOX.g1StartConcMarkCycle();
85 Helpers.waitTillCMCFinished(WHITE_BOX, 0);
86 }
87 },
88 FULL_GC_MEMORY_PRESSURE {
89 @Override
90 public void provoke() {
91 WHITE_BOX.fullGC();
92 }
93 };
94 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
95
96 public abstract void provoke();
97 }
98
99 /**
100 * Factory for weak and soft references.
101 * Allocates byte array of ALLOCATION_SIZE and returns weak/soft reference on it.
102 */
103 private enum REF_FACTORY {
104 WEAK {
105 @Override
106 public Reference<byte[]> create() {
107 return new WeakReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
108 }
109 },
110 SOFT {
111 @Override
112 public Reference<byte[]> create() {
113 return new SoftReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
114 }
115 };
116
117 private static final ReferenceQueue<byte[]> referenceQueqe = new ReferenceQueue<>();
118 private static final int ALLOCATION_SIZE = WhiteBox.getWhiteBox().g1RegionSize() * 2 / 3;
119
120 /**
121 * Factory method
122 *
123 * @return weak/soft reference on byte array of ALLOCATION_SIZE
124 */
125 public abstract Reference<byte[]> create();
126 }
127
128
129 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
130
131 /**
132 * Does actual testing:
133 * Gets a reference
134 * Gets address of referenced object using WB method
135 * Calls gc of provided type
136 * Checks that object was/was not deleted using WB methods.
137 */
138 public static void doTesting(GC gc, REF_FACTORY ref) {
139
140 System.out.println(String.format("Testing %s reference behavior after %s", ref.name(), gc.name()));
141
142 Reference<byte[]> reference = ref.create();
143 Asserts.assertNotNull(reference, "Test Bug: failed to allocate reference");
144 long adr = WHITE_BOX.getObjectAddress(reference.get());
145
146 //Sanity checks
147 boolean isRefNulled = (reference.get() == null);
148 boolean isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
149 boolean isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
150
151
152 Asserts.assertEquals(isRefNulled, false,
153 "We just allocated an object but reference.get() already returned null");
154
155 Asserts.assertEquals(isRegionFree, false,
156 "We just allocated an object but WB returns that allocation region is still considered free");
157
158 Asserts.assertEquals(isRegionHumongous, true,
159 "We just allocated a humongous object but WB returns that allocation region is not humongous");
160
161 gc.provoke();
162
163 isRefNulled = (reference.get() == null);
164 isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
165 isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
166
167 boolean isObjCollected = isRegionFree || !isRegionHumongous;
168
169 Asserts.assertEquals(isRefNulled, isObjCollected,
170 String.format("There is an inconsistensy between reference and white box "
171 + "method behavior - one considers object referenced with "
172 + "%s type collected and another doesn't!\n"
173 + "\treference.get() returned %snull\n"
174 + "\tWhiteBox methods returned that object was%s collected",
175 reference.getClass().getSimpleName(),
176 (isRefNulled ? "" : "not "),
177 (isObjCollected ? "" : " not")));
178
179 System.out.println("Passed");
180 }
181
182 /**
183 * Entry point
184 *
185 * @param args not used
186 */
187 public static void main(String[] args) {
188 // Full gc - System.gc()
189 TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.WEAK);
190 TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.SOFT);
191
192 // Full gc with memory pressure - WB.fullGC() emulates that no memory left
193 TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.WEAK);
194 TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.SOFT);
195
196 // Young gc
197 TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.WEAK);
198 TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.SOFT);
199
200 // Concurrent mark cycle
201 TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.WEAK);
202 TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.SOFT);
203 }
204 }