PageSize.java revision 8359:ed6389f70257 
1/*
2 * Copyright (c) 2015, 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 * @test
26 * @summary Make sure pageSize() returns a value that is a power of two
27 * @library /testlibrary
28 * @modules java.base/sun.misc
29 *          java.management
30 * @run main PageSize
31 */
32
33import java.lang.reflect.Field;
34import jdk.test.lib.*;
35import sun.misc.Unsafe;
36import static jdk.test.lib.Asserts.*;
37
38public class PageSize {
39    public static void main(String args[]) throws Exception {
40        Unsafe unsafe = Utils.getUnsafe();
41        int pageSize = unsafe.pageSize();
42
43        for (int n = 1; n != 0; n <<= 1) {
44            if (pageSize == n) {
45                return;
46            }
47        }
48        throw new RuntimeException("Expected pagesize to be a power of two, actual pagesize:" + pageSize);
49    }
50}
51