1 /*
   2  * Copyright (c) 2001, 2015, 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
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  24 
  25 #ifndef SHARE_VM_GC_PARALLEL_PSYOUNGGEN_HPP
  26 #define SHARE_VM_GC_PARALLEL_PSYOUNGGEN_HPP
  27 
  28 #include "gc/parallel/objectStartArray.hpp"
  29 #include "gc/parallel/psGenerationCounters.hpp"
  30 #include "gc/parallel/psVirtualspace.hpp"
  31 #include "gc/shared/mutableSpace.hpp"
  32 #include "gc/shared/spaceCounters.hpp"
  33 
  34 class PSMarkSweepDecorator;
  35 
  36 class PSYoungGen : public CHeapObj<mtGC> {
  37   friend class VMStructs;
  38   friend class ParallelScavengeHeap;
  39   friend class AdjoiningGenerations;
  40 
  41  protected:
  42   MemRegion       _reserved;
  43   PSVirtualSpace* _virtual_space;
  44 
  45   // Spaces
  46   MutableSpace* _eden_space;
  47   MutableSpace* _from_space;
  48   MutableSpace* _to_space;
  49 
  50 
  51   // MarkSweep Decorators
  52   PSMarkSweepDecorator* _eden_mark_sweep;
  53   PSMarkSweepDecorator* _from_mark_sweep;
  54   PSMarkSweepDecorator* _to_mark_sweep;
  55 
  56   // Sizing information, in bytes, set in constructor
  57   const size_t _init_gen_size;
  58   const size_t _min_gen_size;
  59   const size_t _max_gen_size;
  60 
  61   // Performance counters
  62   PSGenerationCounters*     _gen_counters;
  63   SpaceCounters*            _eden_counters;
  64   SpaceCounters*            _from_counters;
  65   SpaceCounters*            _to_counters;
  66 
  67   // Initialize the space boundaries
  68   void compute_initial_space_boundaries();
  69 
  70   // Space boundary helper
  71   void set_space_boundaries(size_t eden_size, size_t survivor_size);
  72 
  73   virtual bool resize_generation(size_t eden_size, size_t survivor_size);
  74   virtual void resize_spaces(size_t eden_size, size_t survivor_size);
  75 
  76   // Adjust the spaces to be consistent with the virtual space.
  77   void post_resize();
  78 
  79   // Return number of bytes that the generation can change.
  80   // These should not be used by PSYoungGen
  81   virtual size_t available_for_expansion();
  82   virtual size_t available_for_contraction();
  83 
  84   // Given a desired shrinkage in the size of the young generation,
  85   // return the actual size available for shrinkage.
  86   virtual size_t limit_gen_shrink(size_t desired_change);
  87   // returns the number of bytes available from the current size
  88   // down to the minimum generation size.
  89   size_t available_to_min_gen();
  90   // Return the number of bytes available for shrinkage considering
  91   // the location the live data in the generation.
  92   virtual size_t available_to_live();
  93 
  94  public:
  95   // Initialize the generation.
  96   PSYoungGen(size_t        initial_byte_size,
  97              size_t        minimum_byte_size,
  98              size_t        maximum_byte_size);
  99   void initialize_work();
 100   virtual void initialize(ReservedSpace rs, size_t alignment);
 101   virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment);
 102 
 103   MemRegion reserved() const            { return _reserved; }
 104 
 105   bool is_in(const void* p) const   {
 106       return _virtual_space->contains((void *)p);
 107   }
 108 
 109   bool is_in_reserved(const void* p) const   {
 110       return reserved().contains((void *)p);
 111   }
 112 
 113   MutableSpace*   eden_space() const    { return _eden_space; }
 114   MutableSpace*   from_space() const    { return _from_space; }
 115   MutableSpace*   to_space() const      { return _to_space; }
 116   PSVirtualSpace* virtual_space() const { return _virtual_space; }
 117 
 118   // For Adaptive size policy
 119   size_t min_gen_size() { return _min_gen_size; }
 120 
 121   // MarkSweep support
 122   PSMarkSweepDecorator* eden_mark_sweep() const    { return _eden_mark_sweep; }
 123   PSMarkSweepDecorator* from_mark_sweep() const    { return _from_mark_sweep; }
 124   PSMarkSweepDecorator* to_mark_sweep() const      { return _to_mark_sweep;   }
 125 
 126   void precompact();
 127   void adjust_pointers();
 128   void compact();
 129 
 130   // Called during/after GC
 131   void swap_spaces();
 132 
 133   // Resize generation using suggested free space size and survivor size
 134   // NOTE:  "eden_size" and "survivor_size" are suggestions only. Current
 135   //        heap layout (particularly, live objects in from space) might
 136   //        not allow us to use these values.
 137   void resize(size_t eden_size, size_t survivor_size);
 138 
 139   // Size info
 140   size_t capacity_in_bytes() const;
 141   size_t used_in_bytes() const;
 142   size_t free_in_bytes() const;
 143 
 144   size_t capacity_in_words() const;
 145   size_t used_in_words() const;
 146   size_t free_in_words() const;
 147 
 148   // The max this generation can grow to
 149   size_t max_size() const { return _reserved.byte_size(); }
 150 
 151   // The max this generation can grow to if the boundary between
 152   // the generations are allowed to move.
 153   size_t gen_size_limit() const { return _max_gen_size; }
 154 
 155   bool is_maximal_no_gc() const {
 156     return true;  // Never expands except at a GC
 157   }
 158 
 159   // Allocation
 160   HeapWord* allocate(size_t word_size) {
 161     HeapWord* result = eden_space()->cas_allocate(word_size);
 162     return result;
 163   }
 164 
 165   HeapWord** top_addr() const   { return eden_space()->top_addr(); }
 166   HeapWord** end_addr() const   { return eden_space()->end_addr(); }
 167 
 168   // Iteration.
 169   void oop_iterate(ExtendedOopClosure* cl);
 170   void object_iterate(ObjectClosure* cl);
 171 
 172   virtual void reset_after_change();
 173   virtual void reset_survivors_after_shrink();
 174 
 175   // Performance Counter support
 176   void update_counters();
 177 
 178   // Debugging - do not use for time critical operations
 179   void print() const;
 180   void print_on(outputStream* st) const;
 181   void print_used_change(size_t prev_used) const;
 182   virtual const char* name() const { return "PSYoungGen"; }
 183 
 184   void verify();
 185 
 186   // Space boundary invariant checker
 187   void space_invariants() PRODUCT_RETURN;
 188 
 189   // Helper for mangling survivor spaces.
 190   void mangle_survivors(MutableSpace* s1,
 191                         MemRegion s1MR,
 192                         MutableSpace* s2,
 193                         MemRegion s2MR) PRODUCT_RETURN;
 194 
 195   void record_spaces_top() PRODUCT_RETURN;
 196 };
 197 
 198 #endif // SHARE_VM_GC_PARALLEL_PSYOUNGGEN_HPP