Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

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 /*

  * @test TestNoEagerReclaimOfHumongousRegions

  * @bug 8139424

  * @summary Test to check that a live humongous object is not eagerly reclaimed. This is a regression test for

  *          8139424 and the test will crash if an eager reclaim occur. The test is not 100% deterministic and

  *          might pass even if there are problems in the code, but it will never crash unless there is a problem.

  * @requires vm.gc=="G1" | vm.gc=="null"

  * @key gc

  * @library /testlibrary /testlibrary/whitebox

  * @modules java.base/sun.misc

  * @build TestNoEagerReclaimOfHumongousRegions

  * @run main ClassFileInstaller sun.hotspot.WhiteBox

  *                              sun.hotspot.WhiteBox$WhiteBoxPermission

  * @run main/othervm -Xbootclasspath/a:. -XX:+PrintGC -XX:+UseG1GC -XX:MaxTenuringThreshold=0 -XX:G1RSetSparseRegionEntries=32 -XX:G1HeapRegionSize=1m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:+UnlockExperimentalVMOptions -XX:+G1TraceEagerReclaimHumongousObjects TestNoEagerReclaimOfHumongousRegions

  */

 import java.util.LinkedList;

 import sun.hotspot.WhiteBox;

 public class TestNoEagerReclaimOfHumongousRegions {

     // Helper class to keep reference to humongous byte[].

     static class LargeRef {

         private byte[] _ref;

         LargeRef(byte[] ref) {

             _ref = ref;

         }

         byte[] ref() { return _ref; }

     }

     static LargeRef humongous_reference_holder;

     public static void main(String[] args) throws InterruptedException{

         WhiteBox wb = WhiteBox.getWhiteBox();

         LinkedList<Object> garbageAndRefList = new LinkedList<Object>();

         // Creating a 1M large byte array. Since the test specifies the heap

         // region size to be 1m this will be a humongous object. We then

         // store a pointer to the array in the static object to keep it live

         // during the whole test.

         humongous_reference_holder = new LargeRef(new byte[1 * 1024 * 1024]);

         // Create some garbage and a reference to the humongous object each round.

         for (int i = 0; i < 32; i++) {

             garbageAndRefList.add(new byte[400*1000]);

             garbageAndRefList.add(new LargeRef(humongous_reference_holder.ref()));

             // Promote to old, goal is to get rem-set entries for the humongous

             // object from different regions. The test specifies MaxTenuringThreshold=0,

             // this will make sure we get objects promoted to old at once.

             wb.youngGC();

         }

         // Clear the garbage and reference list.

         garbageAndRefList.clear();

         // Run a concurrent mark cycle to mark all references but the static one as dead.

         wb.g1StartConcMarkCycle();

         while (wb.g1InConcurrentMark()) {

             Thread.sleep(100);

         }

         // Run a young collection to make sure humongous object still can't be eagerly reclaimed.

         wb.youngGC();

         // Will crash/assert if humongous object has been reclaimed.

         wb.fullGC();

     }

 }