1 /*
2 * Copyright (c) 2014, 2026, 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 TestEagerReclaimHumongousRegions
28 * @bug 8051973
29 * @summary Test to make sure that eager reclaim of humongous objects correctly works.
30 * @requires vm.gc.G1
31 * @requires vm.debug
32 * @library /test/lib /testlibrary /
33 * @modules java.base/jdk.internal.misc
34 * java.management
35 * @enablePreview
36 * @build jdk.test.whitebox.WhiteBox
37 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
38 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -Xbootclasspath/a:. -XX:+WhiteBoxAPI --enable-preview gc.g1.TestEagerReclaimHumongousRegions
39 */
40
41 import java.util.ArrayList;
42 import java.util.List;
43 import java.util.regex.Matcher;
44 import java.util.regex.MatchResult;
45 import java.util.regex.Pattern;
46
47 import jdk.test.lib.Asserts;
48 import jdk.test.lib.process.OutputAnalyzer;
49 import jdk.test.lib.process.ProcessTools;
50 import jdk.test.whitebox.WhiteBox;
51
52 public class TestEagerReclaimHumongousRegions {
53 private static final WhiteBox WB = WhiteBox.getWhiteBox();
54
55 enum ArrayType { TYPE_ARRAY, OBJ_ARRAY, FLAT_TYPE_ARRAY, FLAT_OBJ_ARRAY }
56 enum ReferencePolicy { KEEP, DROP }
57 enum AllocationTiming { BEFORE_MARK_START, AFTER_MARK_START}
58
59 enum ExpectedState {
60 MARKED_CANDIDATE_RECLAIMED(true, true, true),
61 MARKED_CANDIDATE_NOT_RECLAIMED(true, true, false),
62 MARKED_NOTCANDIDATE_NOTRECLAIMED(true, false, false),
63 NOTMARKED_CANDIDATE_RECLAIMED(false, true, true),
64 NOTMARKED_CANDIDATE_NOTRECLAIMED(false, true, false),
65 NOTMARKED_NOTCANDIDATE_NOTRECLAIMED(false, false, false);
66
67 final boolean marked;
68 final boolean candidate;
69 final boolean reclaimed;
70
71 ExpectedState(boolean marked, boolean candidate, boolean reclaimed) {
72 this.marked = marked;
73 this.candidate = candidate;
74 this.reclaimed = reclaimed;
75 }
76 }
77
78 /**
79 * Run the helper VM, passing configuration arguments, simulating an application allocating some kind of humongous object at a
80 * point during the induced concurrent mark, and executing a young gc.
81 *
82 * @param type Whether the allocated humongous object should be a typeArray, or an objArray.
83 * @param refPolicy Drop the reference to the allocated object after reaching the given phase or keep.
84 * @param timing Allocate the humongous objects before or after reaching the given phase.
85 * @param phase The phase during concurrent mark to reach before triggering a young garbage collection.
86 * @return Returns the stdout of the VM.
87 */
88 private static String runHelperVM(List<String> args, ArrayType type, ReferencePolicy refPolicy, AllocationTiming timing, String phase) throws Exception {
89
90 int arrayKind = type.ordinal();
91 boolean keepReference = (refPolicy == ReferencePolicy.KEEP);
92 boolean allocateAfter = (timing == AllocationTiming.AFTER_MARK_START);
93
94 OutputAnalyzer output = ProcessTools.executeLimitedTestJava("-XX:+UseG1GC",
95 "-Xmx20M",
96 "-Xms20M",
97 "-XX:+UnlockDiagnosticVMOptions",
98 "-XX:+VerifyAfterGC",
99 "-Xbootclasspath/a:.",
100 "-Xlog:gc=debug,gc+humongous=debug",
101 "-XX:+UnlockDiagnosticVMOptions",
102 "-XX:+WhiteBoxAPI",
103 "--enable-preview",
104 TestEagerReclaimHumongousRegionsClearMarkBitsRunner.class.getName(),
105 String.valueOf(arrayKind),
106 String.valueOf(keepReference),
107 String.valueOf(allocateAfter),
108 phase);
109
110 String log = output.getStdout();
111 System.out.println(log);
112 output.shouldHaveExitValue(0);
113 return log;
114 }
115
116 private static List<String> testArgs() throws Exception {
117 return List.of("-XX:+UseG1GC",
118 "-Xmx20M",
119 "-Xms20m",
120 "-XX:+UnlockDiagnosticVMOptions",
121 "-XX:+VerifyAfterGC",
122 "-Xbootclasspath/a:.",
123 "-Xlog:gc=debug,gc+humongous=debug",
124 "-XX:+UnlockDiagnosticVMOptions",
125 "-XX:+WhiteBoxAPI");
126 }
127
128 private static String boolToInt(boolean value) {
129 return value ? "1" : "0";
130 }
131
132 private static void verifyLog(String log, AllocationTiming timing, ExpectedState expected) {
133 // Find the log output indicating that the humongous object has been reclaimed, and marked and verify for the expected results.
134 // [0.351s][debug][gc,humongous] GC(3) Humongous region 2 (object size 4194320 @ 0x00000000fee00000) remset 0 code roots 0 marked 1 pinned count 0 reclaim candidate 1 type array 1
135
136 // Now check the result of the reclaim attempt. We are interested in the last such message (as mentioned above, we might get two).
137 String patternString = "gc,humongous.* marked (\\d) pin.*candidate (\\d)";
138 Pattern pattern = Pattern.compile(patternString);
139 Matcher matcher = pattern.matcher(log);
140
141 List<MatchResult> found = new ArrayList<MatchResult>();
142 while (matcher.find()) {
143 found.add(matcher.toMatchResult());
144 }
145
146 Asserts.assertTrue(found.size() == 1 || found.size() == 2, "Unexpected number of log messages " + found.size());
147
148 if (found.size() == 2) {
149 Asserts.assertTrue(timing == AllocationTiming.BEFORE_MARK_START, "Should only have two messages if allocating the object before mark start");
150 MatchResult mr = found.removeFirst();
151 Asserts.assertTrue(mr.group(1).equals(boolToInt(false)), "Should not be marked before mark start " + mr.group());
152 Asserts.assertTrue(mr.group(2).equals(boolToInt(true)), "Should be candidate before mark start " + mr.group());
153 }
154
155 MatchResult mr = found.removeFirst();
156 Asserts.assertTrue(mr.group(1).equals(boolToInt(expected.marked)), "Expected that region was " + (expected.marked ? "" : "not ") + " marked but is " + mr.group());
157 Asserts.assertTrue(mr.group(2).equals(boolToInt(expected.candidate)), "Expected that region was " + (expected.candidate ? "" : "not ") + " candidate but is " + mr.group());
158
159 boolean reclaimed = Pattern.compile("Reclaimed humongous region .*").matcher(log).find();
160 Asserts.assertTrue(expected.reclaimed == reclaimed, "Wrong log output reclaiming humongous region");
161 }
162
163 private static void runTest(ArrayType type,
164 ReferencePolicy refPolicy,
165 AllocationTiming timing,
166 String phase,
167 ExpectedState expected) throws Exception {
168 List<String> vmArgs = testArgs();
169
170 ArrayList<String> args = new ArrayList(vmArgs);
171 String log = runHelperVM(args, type, refPolicy, timing, phase);
172 verifyLog(log, timing, expected);
173
174 ArrayList<String> jfrArgs = new ArrayList(vmArgs);
175 jfrArgs.addLast("-XX:StartFlightRecording=settings=profile");
176 String jfrLog = runHelperVM(jfrArgs, type, refPolicy, timing, phase);
177 verifyLog(jfrLog, timing, expected);
178 }
179
180 private static void runTestNoRefsFor(ArrayType ot) throws Exception {
181 System.out.println("Tests checking eager reclaim for when the object of type " + ot + " is allocated before mark start.");
182 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.MARKED_CANDIDATE_RECLAIMED);
183 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.MARKED_CANDIDATE_RECLAIMED);
184 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
185
186 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.MARKED_CANDIDATE_NOT_RECLAIMED);
187 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.MARKED_CANDIDATE_NOT_RECLAIMED);
188 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
189
190 System.out.println("Tests checking eager reclaim for when the object of type " + ot + " is allocated after mark start.");
191 // These must not be marked (as they were allocated after mark start), and they are always candidates. Reclamation depends on whether there is a reference.
192 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
193 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
194 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
195
196 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
197 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
198 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
199 }
200
201 private static void runTestWithRefsFor(ArrayType ot) throws Exception {
202 System.out.println("Tests checking eager reclaim for when the object of type " + ot + " is allocated before mark start.");
203 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.MARKED_NOTCANDIDATE_NOTRECLAIMED);
204 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.MARKED_CANDIDATE_RECLAIMED);
205 runTest(ot, ReferencePolicy.DROP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
206
207 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.MARKED_NOTCANDIDATE_NOTRECLAIMED);
208 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.MARKED_CANDIDATE_NOT_RECLAIMED);
209 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.BEFORE_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
210
211 System.out.println("Tests checking eager reclaim for when the object of type " + ot + " is allocated after mark start.");
212 // These must not be marked (as they were allocated after mark start), and they are always candidates. Reclamation depends on whether there is a reference.
213 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
214 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
215 runTest(ot, ReferencePolicy.DROP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_RECLAIMED);
216
217 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.BEFORE_MARKING_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
218 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_REBUILD_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
219 runTest(ot, ReferencePolicy.KEEP, AllocationTiming.AFTER_MARK_START, WB.G1_BEFORE_CLEANUP_COMPLETED, ExpectedState.NOTMARKED_CANDIDATE_NOTRECLAIMED);
220 }
221
222 public static void main(String[] args) throws Exception {
223 runTestNoRefsFor(ArrayType.TYPE_ARRAY);
224 runTestWithRefsFor(ArrayType.OBJ_ARRAY);
225 runTestNoRefsFor(ArrayType.FLAT_TYPE_ARRAY);
226 runTestWithRefsFor(ArrayType.FLAT_OBJ_ARRAY);
227 }
228 }
229
230 class TestEagerReclaimHumongousRegionsClearMarkBitsRunner {
231 value class RefValue {
232 Object o;
233 RefValue() { o = null; }
234 }
235
236 value class IntValue {
237 int i;
238 IntValue() { i = 0; }
239 }
240
241 private static final WhiteBox WB = WhiteBox.getWhiteBox();
242 private static final int SIZE = 1024 * 1024;
243
244 private static Object allocateHumongousObj(int type) {
245 switch (type) {
246 case 0: return new int[SIZE];
247 case 1: return new Object[SIZE];
248 case 2: return new IntValue[SIZE];
249 case 3: return new RefValue[SIZE];
250 default: throw new RuntimeException("Unknown object type " + type);
251 }
252 }
253
254 public static void main(String[] args) throws Exception {
255 if (args.length != 4) {
256 throw new Exception("Invalid number of arguments " + args.length);
257 }
258 int arrayType = Integer.parseInt(args[0]);
259 boolean keepReference = Boolean.parseBoolean(args[1]);
260 boolean allocateAfter = Boolean.parseBoolean(args[2]);
261 String phase = args[3];
262
263 System.out.println("arrayType: " + arrayType + " keepReference: " + keepReference + " allocateAfter " + allocateAfter + " phase: " + phase);
264 WB.fullGC();
265
266 Object largeObj = null; // Allocated humongous object.
267 if (!allocateAfter) {
268 largeObj = allocateHumongousObj(arrayType);
269 }
270
271 WB.concurrentGCAcquireControl();
272 WB.concurrentGCRunTo(phase);
273
274 System.out.println("Phase " + phase + " reached");
275
276 if (allocateAfter) {
277 largeObj = allocateHumongousObj(arrayType);
278 }
279
280 if (!keepReference) {
281 largeObj = null;
282 }
283 WB.youngGC(); // May reclaim the humongous object.
284
285 WB.concurrentGCRunToIdle();
286
287 System.out.println("Large object at " + largeObj); // Keepalive.
288 }
289 }