1 /*

     2  * Copyright (c) 2014, 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

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    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

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    23 

    24 /**

    25  * @test TestSmallHeap

    26  * @bug 8067438

    27  * @requires vm.gc=="null"

    28  * @summary Verify that starting the VM with a small heap works

    29  * @run main/othervm -Xmx4m -XX:+UseParallelGC TestSmallHeap

    30  * @run main/othervm -Xmx4m -XX:+UseSerialGC TestSmallHeap

    31  * @run main/othervm -Xmx4m -XX:+UseG1GC TestSmallHeap

    32  * @run main/othervm -Xmx4m -XX:+UseConcMarkSweepGC -XX:CMSMarkStackSizeMax=1032 TestSmallHeap

    33  *

    34  * Note: It would be nice to verify the minimal supported heap size here,

    35  * but that turns out to be quite tricky since we align the heap size based

    36  * on the card table size. And the card table size is aligned based on the

    37  * minimal pages size provided by the os. This means that on most platforms,

    38  * where the minimal page size is 4k, we get a minimal heap size of 2m but

    39  * on Solaris/Sparc we have a page size of 8k and get a minimal heap size

    40  * of 8m.

    41  * There is also no check in the VM for verifying that the maximum heap size

    42  * is larger than the supported minimal heap size. This means that specifying

    43  * -Xmx1m on the command line is fine but will give a heap of 2m (or 4m).

    44  * To work around these rather strange behaviors this test uses 4m for all

    45  * platforms.

    46  */

    47 

    48 import sun.management.ManagementFactoryHelper;

    49 import static com.oracle.java.testlibrary.Asserts.*;

    50 

    51 public class TestSmallHeap {

    52 

    53     public static void main(String[] args) {

    54         String maxHeap = ManagementFactoryHelper.getDiagnosticMXBean().getVMOption("MaxHeapSize").getValue();

    55         String expectedMaxHeap = "4194304";

    56         assertEQ(maxHeap, expectedMaxHeap);

    57     }

    58 }