jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.hpp@c96030fff130

6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

     1 /*

     2  * Copyright (c) 2007 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 class CardTableRS;   // fwd decl

    26 class ConcurrentMarkSweepGeneration;

    28 // A PermGen implemented with a CMS space, collected by a CMS collector.

    29 class CMSPermGen:  public PermGen {

    30   friend class VMStructs;

    32  protected:

    33   // The "generation" view.

    34   ConcurrentMarkSweepGeneration* _gen;

    36  public:

    37   CMSPermGen(ReservedSpace rs, size_t initial_byte_size,

    38              CardTableRS* ct, FreeBlockDictionary::DictionaryChoice);

    40   HeapWord* mem_allocate(size_t size);

    42   void compute_new_size();

    44   Generation* as_gen() const { return _gen; }

    45 };

    47 // This is the "generation" view of a CMSPermGen.

    48 class CMSPermGenGen: public ConcurrentMarkSweepGeneration {

    49   // Abstractly, this is a subtype that gets access to protected fields.

    50   friend class CMSPermGen;

    51 public:

    52   CMSPermGenGen(ReservedSpace rs, size_t initial_byte_size,

    53                        int level, CardTableRS* ct):

    54     // See comments in the constructor for CompactibleFreeListSpace

    55     // regarding not using adaptive free lists for a perm gen.

    56     ConcurrentMarkSweepGeneration(rs, initial_byte_size, // MinPermHeapExapnsion

    57       level, ct, false /* use adaptive freelists */,

    58       (FreeBlockDictionary::DictionaryChoice)CMSDictionaryChoice)

    59   {}

    61   void initialize_performance_counters();

    63   const char* name() const {

    64     return "concurrent-mark-sweep perm gen";

    65   }

    67   const char* short_name() const {

    68     return "CMS Perm";

    69   }

    71   bool must_be_youngest() const { return false; }

    72   bool must_be_oldest() const { return false; }

    73 };

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

src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.hpp@c96030fff130

src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.hpp