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

/*
 * Copyright (c) 2007 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * 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.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
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class CardTableRS;   // fwd decl
class ConcurrentMarkSweepGeneration;

// A PermGen implemented with a CMS space, collected by a CMS collector.
class CMSPermGen:  public PermGen {
  friend class VMStructs;

  HeapWord* mem_allocate_work(size_t size);
 protected:
  // The "generation" view.
  ConcurrentMarkSweepGeneration* _gen;

 public:
  CMSPermGen(ReservedSpace rs, size_t initial_byte_size,
             CardTableRS* ct, FreeBlockDictionary::DictionaryChoice);

  HeapWord* mem_allocate(size_t size);

  void compute_new_size();

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

// This is the "generation" view of a CMSPermGen.
class CMSPermGenGen: public ConcurrentMarkSweepGeneration {
  // Abstractly, this is a subtype that gets access to protected fields.
  friend class CMSPermGen;
public:
  CMSPermGenGen(ReservedSpace rs, size_t initial_byte_size,
                       int level, CardTableRS* ct):
    // See comments in the constructor for CompactibleFreeListSpace
    // regarding not using adaptive free lists for a perm gen.
    ConcurrentMarkSweepGeneration(rs, initial_byte_size, // MinPermHeapExapnsion
      level, ct, false /* use adaptive freelists */,
      (FreeBlockDictionary::DictionaryChoice)CMSDictionaryChoice)
  {}

  void initialize_performance_counters();

  const char* name() const {
    return "concurrent-mark-sweep perm gen";
  }

  const char* short_name() const {
    return "CMS Perm";
  }

  bool must_be_youngest() const { return false; }
  bool must_be_oldest() const { return false; }
};