/*

 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

// All heaps contains a "permanent generation," containing permanent

// (reflective) objects.  This is like a regular generation in some ways,

// but unlike one in others, and so is split apart.

class Generation;

class GenRemSet;

class CSpaceCounters;

// PermGen models the part of the heap used to allocate class meta-data.

class PermGen : public CHeapObj {

  friend class VMStructs;

 protected:

  size_t _capacity_expansion_limit;  // maximum expansion allowed without a

                                     // full gc occurring

  void set_capacity_expansion_limit(size_t limit) {

    assert_locked_or_safepoint(Heap_lock);

    _capacity_expansion_limit = limit;

  }

  HeapWord* mem_allocate_in_gen(size_t size, Generation* gen);

  // Along with mem_allocate_in_gen() above, implements policy for

  // "scheduling" allocation/expansion/collection of the perm gen.

  // The virtual method request_...() below can be overridden by

  // subtypes that want to implement a different expansion/collection

  // policy from the default provided.

  virtual HeapWord* request_expand_and_allocate(Generation* gen, size_t size,

                                                GCCause::Cause prev_cause);

 public:

  enum Name {

    MarkSweepCompact, MarkSweep, ConcurrentMarkSweep

  };

  // Permanent allocation (initialized)

  virtual HeapWord* mem_allocate(size_t size) = 0;

  // Mark sweep support

  virtual void compute_new_size() = 0;

  // Ideally, we would use MI (IMHO) but we'll do delegation instead.

  virtual Generation* as_gen() const = 0;

  virtual void oop_iterate(OopClosure* cl) {

    Generation* g = as_gen();

    assert(g != NULL, "as_gen() NULL");

    g->oop_iterate(cl);

  }

  virtual void object_iterate(ObjectClosure* cl) {

    Generation* g = as_gen();

    assert(g != NULL, "as_gen() NULL");

    g->object_iterate(cl);

  }

  // Performance Counter support

  virtual void update_counters() {

    Generation* g = as_gen();

    assert(g != NULL, "as_gen() NULL");

    g->update_counters();

  }

};