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
25 package gc.g1.humongousObjects;
26
27 import gc.testlibrary.Helpers;
28 import jdk.test.lib.Asserts;
29 import sun.hotspot.WhiteBox;
30
31 import java.lang.ref.Reference;
32 import java.lang.ref.ReferenceQueue;
33 import java.lang.ref.SoftReference;
34 import java.lang.ref.WeakReference;
35
36 /**
37 * @test TestObjectCollected
38 * @summary checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
39 * actual object behavior
40 * @requires vm.gc.G1
41 * @library /test/lib /
42 * @modules java.base/jdk.internal.misc
43 * @modules java.management
44 * @build sun.hotspot.WhiteBox
45 * @run driver ClassFileInstaller sun.hotspot.WhiteBox
46 * sun.hotspot.WhiteBox$WhiteBoxPermission
47 *
48 * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
49 * -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xms200m -Xmx200m -Xlog:gc
50 * -XX:InitiatingHeapOccupancyPercent=100 -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectCollected.gc.log
51 * gc.g1.humongousObjects.TestObjectCollected
52 */
53
54
55 /**
56 * Test checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
57 * actual object behavior.
58 * So if object was collected, reference.get() should return null and vice versa
59 * Since we check humongous objects after such an object is collected the region where it was allocated becomes free
60 * or/and change type to non-humongous. Two WhiteBox method were used - first returns if a region containing certain
61 * address is free and second - if a region containing certain address is humongous
62 */
63
64 public class TestObjectCollected {
65 /**
66 * Provides methods to initiate GC of requested type
67 */
68 private enum GC {
69 YOUNG_CG {
70 @Override
71 public void provoke() {
72 WHITE_BOX.youngGC();
73 }
74 },
75 FULL_GC {
76 @Override
77 public void provoke() {
78 System.gc();
79 }
80 },
81 CMC {
82 @Override
83 public void provoke() {
84 Helpers.waitTillCMCFinished(WHITE_BOX, 0);
85 WHITE_BOX.g1StartConcMarkCycle();
86 Helpers.waitTillCMCFinished(WHITE_BOX, 0);
87 }
88 },
89 FULL_GC_MEMORY_PRESSURE {
90 @Override
91 public void provoke() {
92 WHITE_BOX.fullGC();
93 }
94 };
95 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
96
97 public abstract void provoke();
98 }
99
100 /**
101 * Factory for weak and soft references.
102 * Allocates byte array of ALLOCATION_SIZE and returns weak/soft reference on it.
103 */
104 private enum REF_FACTORY {
105 WEAK {
106 @Override
107 public Reference<byte[]> create() {
108 return new WeakReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
109 }
110 },
111 SOFT {
112 @Override
113 public Reference<byte[]> create() {
114 return new SoftReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
115 }
116 };
117
118 private static final ReferenceQueue<byte[]> referenceQueqe = new ReferenceQueue<>();
119 private static final int ALLOCATION_SIZE = WhiteBox.getWhiteBox().g1RegionSize() * 2 / 3;
120
121 /**
122 * Factory method
123 *
124 * @return weak/soft reference on byte array of ALLOCATION_SIZE
125 */
126 public abstract Reference<byte[]> create();
127 }
128
129
130 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
131
132 /**
133 * Does actual testing:
134 * Gets a reference
135 * Gets address of referenced object using WB method
136 * Calls gc of provided type
137 * Checks that object was/was not deleted using WB methods.
138 */
139 public static void doTesting(GC gc, REF_FACTORY ref) {
140
141 System.out.println(String.format("Testing %s reference behavior after %s", ref.name(), gc.name()));
142
143 Reference reference = ref.create();
144 Asserts.assertNotNull(reference, "Test Bug: failed to allocate reference");
145 long adr = WHITE_BOX.getObjectAddress(reference.get());
146
147 //Sanity checks
148 boolean isRefNulled = (reference.get() == null);
149 boolean isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
150 boolean isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
151
152
153 Asserts.assertEquals(isRefNulled, false,
154 "We just allocated an object but reference.get() already returned null");
155
156 Asserts.assertEquals(isRegionFree, false,
157 "We just allocated an object but WB returns that allocation region is still considered free");
158
159 Asserts.assertEquals(isRegionHumongous, true,
160 "We just allocated a humongous object but WB returns that allocation region is not humongous");
161
162 gc.provoke();
163
164 isRefNulled = (reference.get() == null);
165 isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
166 isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
167
168 boolean isObjCollected = isRegionFree || !isRegionHumongous;
169
170 Asserts.assertEquals(isRefNulled, isObjCollected,
171 String.format("There is an inconsistensy between reference and white box "
172 + "method behavior - one considers object referenced with "
173 + "%s type collected and another doesn't!\n"
174 + "\treference.get() returned %snull\n"
175 + "\tWhiteBox methods returned that object was%s collected",
176 reference.getClass().getSimpleName(),
177 (isRefNulled ? "" : "not "),
178 (isObjCollected ? "" : " not")));
179
180 System.out.println("Passed");
181 }
182
183 /**
184 * Entry point
185 *
186 * @param args not used
187 */
188 public static void main(String[] args) {
189 // Full gc - System.gc()
190 TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.WEAK);
191 TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.SOFT);
192
193 // Full gc with memory pressure - WB.fullGC() emulates that no memory left
194 TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.WEAK);
195 TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.SOFT);
196
197 // Young gc
198 TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.WEAK);
199 TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.SOFT);
200
201 // Concurrent mark cycle
202 TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.WEAK);
203 TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.SOFT);
204 }
205 }