1 /*
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  3  * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
  4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  5  *
  6  * This code is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 only, as
  8  * published by the Free Software Foundation.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
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 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 25 
 26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP
 27 #define SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP
 28 
 29 #include "memory/allocation.hpp"
 30 #include "memory/virtualspace.hpp"
 31 #include "gc/shenandoah/shenandoahHeap.hpp"
 32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
 33 #include "gc/shenandoah/shenandoahPadding.hpp"
 34 
 35 class ShenandoahCollectionSet : public CHeapObj<mtGC> {
 36   friend class ShenandoahHeap;
 37 private:
 38   size_t const          _map_size;
 39   size_t const          _region_size_bytes_shift;
 40   ReservedSpace         _map_space;
 41   char* const           _cset_map;
 42   // Bias cset map's base address for fast test if an oop is in cset
 43   char* const           _biased_cset_map;
 44 
 45   ShenandoahHeap* const _heap;
 46 
 47   bool                  _has_old_regions;
 48   size_t                _garbage;
 49   size_t                _used;
 50   size_t                _live;
 51   size_t                _region_count;
 52 
 53   size_t                _young_bytes_to_evacuate;
 54   size_t                _young_bytes_to_promote;
 55   size_t                _old_bytes_to_evacuate;
 56 
 57   // How many bytes of old garbage are present in a mixed collection set?
 58   size_t                _old_garbage;
 59 
 60   // Points to array identifying which tenure-age regions have been preselected
 61   // for inclusion in collection set. This field is only valid during brief
 62   // spans of time while collection set is being constructed.
 63   bool*                 _preselected_regions;
 64 
 65   // When a region having memory available to be allocated is added to the collection set, the region's available memory
 66   // should be subtracted from what's available.
 67   size_t                _young_available_bytes_collected;
 68 
 69   shenandoah_padding(0);
 70   volatile size_t       _current_index;
 71   shenandoah_padding(1);
 72 
 73 public:
 74   ShenandoahCollectionSet(ShenandoahHeap* heap, ReservedSpace space, char* heap_base);
 75 
 76   // Add region to collection set
 77   void add_region(ShenandoahHeapRegion* r);
 78 
 79   // MT version
 80   ShenandoahHeapRegion* claim_next();
 81 
 82   // Single-thread version
 83   ShenandoahHeapRegion* next();
 84 
 85   size_t count()  const { return _region_count; }
 86   bool is_empty() const { return _region_count == 0; }
 87 
 88   void clear_current_index() {
 89     _current_index = 0;
 90   }
 91 
 92   inline bool is_in(ShenandoahHeapRegion* r) const;
 93   inline bool is_in(size_t region_idx)       const;
 94   inline bool is_in(oop obj)                 const;
 95   inline bool is_in_loc(void* loc)           const;
 96 
 97   void print_on(outputStream* out) const;
 98 
 99   // It is not known how many of these bytes will be promoted.
100   inline size_t get_young_bytes_reserved_for_evacuation();
101   inline size_t get_old_bytes_reserved_for_evacuation();
102 
103   inline size_t get_young_bytes_to_be_promoted();
104 
105   size_t get_young_available_bytes_collected() { return _young_available_bytes_collected; }
106 
107   inline size_t get_old_garbage();
108 
109   void establish_preselected(bool *preselected) { _preselected_regions = preselected; }
110   void abandon_preselected() { _preselected_regions = nullptr; }
111   bool is_preselected(size_t region_idx) { return (_preselected_regions != nullptr) && _preselected_regions[region_idx]; }
112 
113   bool has_old_regions() const { return _has_old_regions; }
114   size_t used()          const { return _used; }
115   size_t live()          const { return _live; }
116   size_t garbage()       const { return _garbage; }
117 
118   void clear();
119 
120 private:
121   char* map_address() const {
122     return _cset_map;
123   }
124   char* biased_map_address() const {
125     return _biased_cset_map;
126   }
127 };
128 
129 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCOLLECTIONSET_HPP