1 /*
   2  * Copyright (c) 2000, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_PERMGEN_HPP
  26 #define SHARE_VM_MEMORY_PERMGEN_HPP
  27 
  28 #include "gc_interface/gcCause.hpp"
  29 #include "memory/generation.hpp"
  30 #include "memory/iterator.hpp"
  31 #include "runtime/handles.hpp"
  32 #include "runtime/mutexLocker.hpp"
  33 #include "runtime/virtualspace.hpp"
  34 
  35 // All heaps contains a "permanent generation," containing permanent
  36 // (reflective) objects.  This is like a regular generation in some ways,
  37 // but unlike one in others, and so is split apart.
  38 
  39 class Generation;
  40 class GenRemSet;
  41 class CSpaceCounters;
  42 
  43 // PermGen models the part of the heap used to allocate class meta-data.
  44 
  45 class PermGen : public CHeapObj {
  46   friend class VMStructs;
  47  protected:
  48   size_t _capacity_expansion_limit;  // maximum expansion allowed without a
  49                                      // full gc occurring
  50   void set_capacity_expansion_limit(size_t limit) {
  51     assert_locked_or_safepoint(Heap_lock);
  52     _capacity_expansion_limit = limit;
  53   }
  54 
  55   HeapWord* mem_allocate_in_gen(size_t size, Generation* gen);
  56   // Along with mem_allocate_in_gen() above, implements policy for
  57   // "scheduling" allocation/expansion/collection of the perm gen.
  58   // The virtual method request_...() below can be overridden by
  59   // subtypes that want to implement a different expansion/collection
  60   // policy from the default provided.
  61   virtual HeapWord* request_expand_and_allocate(Generation* gen, size_t size,
  62                                                 GCCause::Cause prev_cause);
  63 
  64  public:
  65   enum Name {
  66     MarkSweepCompact, MarkSweep, ConcurrentMarkSweep
  67   };
  68 
  69   // Permanent allocation (initialized)
  70   virtual HeapWord* mem_allocate(size_t size) = 0;
  71 
  72   // Mark sweep support
  73   virtual void compute_new_size() = 0;
  74 
  75   // Ideally, we would use MI (IMHO) but we'll do delegation instead.
  76   virtual Generation* as_gen() const = 0;
  77 
  78   virtual void oop_iterate(OopClosure* cl) {
  79     Generation* g = as_gen();
  80     assert(g != NULL, "as_gen() NULL");
  81     g->oop_iterate(cl);
  82   }
  83 
  84   virtual void object_iterate(ObjectClosure* cl) {
  85     Generation* g = as_gen();
  86     assert(g != NULL, "as_gen() NULL");
  87     g->object_iterate(cl);
  88   }
  89 
  90   // Performance Counter support
  91   virtual void update_counters() {
  92     Generation* g = as_gen();
  93     assert(g != NULL, "as_gen() NULL");
  94     g->update_counters();
  95   }
  96 };
  97 
  98 #endif // SHARE_VM_MEMORY_PERMGEN_HPP