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 Monitor _mem_protect_lock;
34
35 public:
36 static size_t RegionSizeBytes;
37 static size_t RegionSizeShift;
38
39 private:
40 size_t _region_number;
41 volatile size_t liveData;
42 MemRegion reserved;
43 bool _is_in_collection_set;
44
45 bool _humongous_start;
46 bool _humongous_continuation;
47
48 HeapWord* _top_at_mark_start;
49 HeapWord* _top_at_prev_mark_start;
50 HeapWord* _top_prev_mark_bitmap;
51
52 HeapWord* _new_top;
53
54 jint _critical_pins;
55
56 #ifdef ASSERT
57 int _mem_protection_level;
58 #endif
59
60 public:
61 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
62
63 jint initialize_heap_region(HeapWord* start, size_t regionSize, int index);
64
65
66 size_t region_number() const;
67
68 // Roll back the previous allocation of an object with specified size.
69 // Returns TRUE when successful, FALSE if not successful or not supported.
70 bool rollback_allocation(uint size);
71
72 void clearLiveData();
73 void setLiveData(size_t s);
74 inline void increase_live_data(size_t s);
75
76 size_t getLiveData() const;
77
78 void print_on(outputStream* st) const;
79
80 size_t garbage() const;
81
82 void recycle();
83 void reset();
84
85 void oop_iterate_skip_unreachable(ExtendedOopClosure* cl, bool skip_unreachable_objects);
86
87 void marked_object_iterate(ObjectClosure* blk);
88
89 void object_iterate_interruptible(ObjectClosure* blk, bool allow_cancel);
90
91 HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
92
93 HeapWord* block_start_const(const void* p) const;
94
95 // Just before GC we need to fill the current region.
96 void fill_region();
97
98 bool is_in_collection_set() const;
99
100 void set_is_in_collection_set(bool b);
101
102 void set_humongous_start(bool start);
103 void set_humongous_continuation(bool continuation);
104
105 bool is_humongous() const;
106 bool is_humongous_start() const;
107 bool is_humongous_continuation() const;
108
109 #ifdef ASSERT
110 void memProtectionOn();
111 void memProtectionOff();
112 #endif
113
114 static ByteSize is_in_collection_set_offset();
115 // The following are for humongous regions. We need to save the
116 markOop saved_mark_word;
117 void save_mark_word(oop obj) {saved_mark_word = obj->mark();}
118 markOop mark_word() {return saved_mark_word;}
119
120 virtual CompactibleSpace* next_compaction_space() const;
121
122 // Override for scan_and_forward support.
123 void prepare_for_compaction(CompactPoint* cp);
124 void adjust_pointers();
125 void compact();
126
127 void init_top_at_mark_start();
128 void set_top_at_mark_start(HeapWord* top);
129 HeapWord* top_at_mark_start();
130 void reset_top_at_prev_mark_start();
131 HeapWord* top_at_prev_mark_start();
132 HeapWord* top_prev_mark_bitmap();
133
134 void set_top_prev_mark_bitmap(HeapWord* top);
135 void swap_top_at_mark_start();
136
137 inline bool allocated_after_mark_start(HeapWord* addr);
138 bool allocated_after_prev_mark_start(HeapWord* addr) const;
139
140 void set_new_top(HeapWord* new_top) { _new_top = new_top; }
141 HeapWord* new_top() const { return _new_top; }
142
143 void enter_critical();
144 void exit_critical();
145
146 bool is_pinned();
147
148 private:
149 void do_reset();
150
151 };
152
153 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP