1 /*
   2  * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP
  25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP
  26 
  27 #include "gc/shared/space.hpp"
  28 #include "memory/universe.hpp"
  29 #include "utilities/sizes.hpp"
  30 
  31 class ShenandoahHeapRegion : public ContiguousSpace {
  32 private:
  33   static const size_t MIN_REGION_SIZE = 256*K;
  34   static const size_t MIN_NUM_REGIONS = 10;
  35 
  36   static Monitor _mem_protect_lock;
  37 
  38 public:
  39   static size_t RegionSizeBytes;
  40   static size_t RegionSizeShift;
  41 
  42 private:
  43   ShenandoahHeap* _heap;
  44   size_t _region_number;
  45   volatile jint _live_data;
  46   MemRegion reserved;
  47 
  48   bool _humongous_start;
  49   bool _humongous_continuation;
  50 
  51   bool _recycled;
  52 
  53   HeapWord* _new_top;
  54 
  55   volatile jint _critical_pins;
  56 
  57 #ifdef ASSERT
  58   int _mem_protection_level;
  59 #endif
  60 
  61 public:
  62   ShenandoahHeapRegion(ShenandoahHeap* heap, HeapWord* start, size_t regionSize, size_t index);
  63 
  64   static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
  65 
  66   size_t region_number() const;
  67 
  68   // Allocation (return NULL if full)
  69   inline HeapWord* allocate(size_t word_size);
  70 
  71   // Roll back the previous allocation of an object with specified size.
  72   // Returns TRUE when successful, FALSE if not successful or not supported.
  73   bool rollback_allocation(uint size);
  74 
  75   void clear_live_data();
  76   void set_live_data(size_t s);
  77   inline void increase_live_data_words(jint s);
  78 
  79   void set_recently_allocated(bool value);
  80   bool is_recently_allocated() const;
  81 
  82   bool has_live() const;
  83   size_t get_live_data_bytes() const;
  84   size_t get_live_data_words() const;
  85 
  86   void print_on(outputStream* st) const;
  87 
  88   size_t garbage() const;
  89 
  90   void recycle();
  91 
  92   void object_iterate_interruptible(ObjectClosure* blk, bool allow_cancel);
  93 
  94   HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
  95 
  96   HeapWord* block_start_const(const void* p) const;
  97 
  98   // Just before GC we need to fill the current region.
  99   void fill_region();
 100 
 101   bool in_collection_set() const;
 102 
 103   void set_in_collection_set(bool b);
 104 
 105   void set_humongous_start(bool start);
 106   void set_humongous_continuation(bool continuation);
 107 
 108   bool is_humongous() const;
 109   bool is_humongous_start() const;
 110   bool is_humongous_continuation() const;
 111 
 112 #ifdef ASSERT
 113   void memProtectionOn();
 114   void memProtectionOff();
 115 #endif
 116 
 117   // The following are for humongous regions.  We need to save the
 118   markOop saved_mark_word;
 119   void save_mark_word(oop obj) {saved_mark_word = obj->mark();}
 120   markOop mark_word() {return saved_mark_word;}
 121 
 122   virtual CompactibleSpace* next_compaction_space() const;
 123 
 124   // Override for scan_and_forward support.
 125   void prepare_for_compaction(CompactPoint* cp);
 126   void adjust_pointers();
 127   void compact();
 128 
 129   void set_new_top(HeapWord* new_top) { _new_top = new_top; }
 130   HeapWord* new_top() const { return _new_top; }
 131 
 132   void pin();
 133   void unpin();
 134 
 135   bool is_pinned();
 136 
 137 };
 138 
 139 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP