jdk8-mips64-public/hotspot: src/share/vm/memory/referencePolicy.hpp@7b0e9cba0307

6896647: card marks can be deferred too long
Summary: Deferred card marks are now flushed during the gc prologue. Parallel[Scavege,OldGC] and SerialGC no longer defer card marks generated by COMPILER2 as a result of ReduceInitialCardMarks. For these cases, introduced a diagnostic option to defer the card marks, only for the purposes of testing and diagnostics. CMS and G1 continue to defer card marks. Potential performance concern related to single-threaded flushing of deferred card marks in the gc prologue will be addressed in the future.
Reviewed-by: never, johnc

     1 /*

     2  * Copyright 2000-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 // referencePolicy is used to determine when soft reference objects

    26 // should be cleared.

    29 class ReferencePolicy : public CHeapObj {

    30  public:

    31   virtual bool should_clear_reference(oop p)       { ShouldNotReachHere(); return true; }

    32   // Capture state (of-the-VM) information needed to evaluate the policy

    33   virtual void setup() { /* do nothing */ }

    34 };

    36 class NeverClearPolicy : public ReferencePolicy {

    37  public:

    38   bool should_clear_reference(oop p) { return false; }

    39 };

    41 class AlwaysClearPolicy : public ReferencePolicy {

    42  public:

    43   bool should_clear_reference(oop p) { return true; }

    44 };

    46 class LRUCurrentHeapPolicy : public ReferencePolicy {

    47  private:

    48   jlong _max_interval;

    50  public:

    51   LRUCurrentHeapPolicy();

    53   // Capture state (of-the-VM) information needed to evaluate the policy

    54   void setup();

    55   bool should_clear_reference(oop p);

    56 };

    58 class LRUMaxHeapPolicy : public ReferencePolicy {

    59  private:

    60   jlong _max_interval;

    62  public:

    63   LRUMaxHeapPolicy();

    65   // Capture state (of-the-VM) information needed to evaluate the policy

    66   void setup();

    67   bool should_clear_reference(oop p);

    68 };

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

src/share/vm/memory/referencePolicy.hpp@7b0e9cba0307

src/share/vm/memory/referencePolicy.hpp