1 /*
   2  * Copyright (c) 2001, 2013, 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_TENUREDGENERATION_HPP
  26 #define SHARE_VM_MEMORY_TENUREDGENERATION_HPP
  27 
  28 #include "gc_implementation/shared/cSpaceCounters.hpp"
  29 #include "gc_implementation/shared/gcStats.hpp"
  30 #include "gc_implementation/shared/generationCounters.hpp"
  31 #include "memory/generation.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 // TenuredGeneration models the heap containing old (promoted/tenured) objects.
  35 
  36 class ParGCAllocBufferWithBOT;
  37 
  38 class TenuredGeneration: public OneContigSpaceCardGeneration {
  39   friend class VMStructs;
  40  protected:
  41 
  42 #if INCLUDE_ALL_GCS
  43   // To support parallel promotion: an array of parallel allocation
  44   // buffers, one per thread, initially NULL.
  45   ParGCAllocBufferWithBOT** _alloc_buffers;
  46 #endif // INCLUDE_ALL_GCS
  47 
  48   // Retire all alloc buffers before a full GC, so that they will be
  49   // re-allocated at the start of the next young GC.
  50   void retire_alloc_buffers_before_full_gc();
  51 
  52   GenerationCounters*   _gen_counters;
  53   CSpaceCounters*       _space_counters;
  54 
  55  public:
  56   TenuredGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
  57                     GenRemSet* remset);
  58 
  59   Generation::Name kind() { return Generation::MarkSweepCompact; }
  60 
  61   // Printing
  62   const char* name() const;
  63   const char* short_name() const { return "Tenured"; }
  64   bool must_be_youngest() const { return false; }
  65   bool must_be_oldest() const { return true; }
  66 
  67   // Does a "full" (forced) collection invoked on this generation collect
  68   // all younger generations as well? Note that this is a
  69   // hack to allow the collection of the younger gen first if the flag is
  70   // set.
  71   virtual bool full_collects_younger_generations() const {
  72     return !CollectGen0First;
  73   }
  74 
  75   virtual void gc_prologue(bool full);
  76   virtual void gc_epilogue(bool full);
  77   bool should_collect(bool   full,
  78                       size_t word_size,
  79                       bool   is_tlab);
  80 
  81   virtual void collect(bool full,
  82                        bool clear_all_soft_refs,
  83                        size_t size,
  84                        bool is_tlab);
  85   virtual void compute_new_size();
  86 
  87 #if INCLUDE_ALL_GCS
  88   // Overrides.
  89   virtual oop par_promote(int thread_num,
  90                           oop obj, markOop m, size_t word_sz);
  91   virtual void par_promote_alloc_undo(int thread_num,
  92                                       HeapWord* obj, size_t word_sz);
  93   virtual void par_promote_alloc_done(int thread_num);
  94 #endif // INCLUDE_ALL_GCS
  95 
  96   // Performance Counter support
  97   void update_counters();
  98 
  99   // Statistics
 100 
 101   virtual void update_gc_stats(int level, bool full);
 102 
 103   virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;
 104 
 105   void verify_alloc_buffers_clean();
 106 };
 107 
 108 #endif // SHARE_VM_MEMORY_TENUREDGENERATION_HPP