1 /*
2 * Copyright (c) 2019, 2020, 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.z;
25
26 /*
27 * @test TestUncommit
28 * @requires vm.gc.Z & !vm.graal.enabled & vm.compMode != "Xcomp"
29 * @summary Test ZGC uncommit unused memory
30 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=10 gc.z.TestUncommit true 2
31 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms512M -Xmx512M -XX:ZUncommitDelay=10 gc.z.TestUncommit false 1
32 * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=10 -XX:-ZUncommit gc.z.TestUncommit false 1
33 */
34
35 /*
36 * This test is disabled when running with -Xcomp, since it seems to affect
37 * the timing of the test, causing memory to appear to be uncommitted too fast.
38 */
39
40 import java.util.ArrayList;
41
42 public class TestUncommit {
43 private static final int delay = 10; // seconds
44 private static final int allocSize = 200 * 1024 * 1024; // 200M
45 private static final int smallObjectSize = 4 * 1024; // 4K
46 private static final int mediumObjectSize = 2 * 1024 * 1024; // 2M
47 private static final int largeObjectSize = allocSize;
48
49 private static volatile ArrayList<byte[]> keepAlive;
50
51 private static long capacity() {
52 return Runtime.getRuntime().totalMemory();
53 }
54
55 private static void allocate(int objectSize) {
56 keepAlive = new ArrayList<>();
57 for (int i = 0; i < allocSize; i+= objectSize) {
58 keepAlive.add(new byte[objectSize]);
59 }
60 }
61
62 private static void reclaim() {
63 keepAlive = null;
64 System.gc();
65 }
66
67 private static void test(boolean enabled, int objectSize) throws Exception {
68 final var beforeAlloc = capacity();
69
70 // Allocate memory
71 allocate(objectSize);
72
73 final var afterAlloc = capacity();
74
75 // Reclaim memory
76 reclaim();
77
78 // Wait shorter than the uncommit delay
79 Thread.sleep(delay * 1000 / 2);
80
81 final var beforeUncommit = capacity();
82
83 // Wait longer than the uncommit delay
84 Thread.sleep(delay * 1000);
85
86 final var afterUncommit = capacity();
87
88 System.out.println(" Uncommit Enabled: " + enabled);
89 System.out.println(" Uncommit Delay: " + delay);
90 System.out.println(" Object Size: " + objectSize);
91 System.out.println(" Alloc Size: " + allocSize);
92 System.out.println(" Before Alloc: " + beforeAlloc);
93 System.out.println(" After Alloc: " + afterAlloc);
94 System.out.println(" Before Uncommit: " + beforeUncommit);
95 System.out.println(" After Uncommit: " + afterUncommit);
96 System.out.println();
97
98 // Verify
99 if (enabled) {
100 if (beforeUncommit == beforeAlloc) {
101 throw new Exception("Uncommitted too fast");
102 }
103
104 if (afterUncommit >= afterAlloc) {
105 throw new Exception("Uncommitted too slow");
106 }
107
108 if (afterUncommit < beforeAlloc) {
109 throw new Exception("Uncommitted too much");
110 }
111
112 if (afterUncommit > beforeAlloc) {
113 throw new Exception("Uncommitted too little");
114 }
115 } else {
116 if (afterAlloc > beforeUncommit ||
117 afterAlloc > afterUncommit) {
118 throw new Exception("Should not uncommit");
119 }
120 }
121 }
122
123 public static void main(String[] args) throws Exception {
124 final boolean enabled = Boolean.parseBoolean(args[0]);
125 final int iterations = Integer.parseInt(args[1]);
126
127 for (int i = 0; i < iterations; i++) {
128 System.out.println("Iteration " + i);
129 test(enabled, smallObjectSize);
130 test(enabled, mediumObjectSize);
131 test(enabled, largeObjectSize);
132 }
133 }
134 }