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
33 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
34 template <typename SpaceType>
35 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
36 template <typename SpaceType>
37 friend void CompactibleSpace::scan_and_adjust_pointers(SpaceType* space);
38 template <typename SpaceType>
39 friend void CompactibleSpace::scan_and_compact(SpaceType* space);
40
41 private:
42 // Auxiliary functions for scan_and_forward support.
43 // See comments for CompactibleSpace for more information.
44 inline HeapWord* scan_limit() const {
45 return top();
46 }
47
48 inline bool scanned_block_is_obj(const HeapWord* addr) const {
49 return true; // Always true, since scan_limit is top
50 }
51
52 inline size_t scanned_block_size(const HeapWord* addr) const {
53 oop obj = oop(addr+1);
54 size_t size = obj->size() + 1;
55 return size;
56 }
57
58 // Auxiliary functions for scan_and_{forward,adjust_pointers,compact} support.
59 inline size_t adjust_obj_size(size_t size) const {
60 return size + 1;
61 }
62
63 inline size_t obj_size(const HeapWord* addr) const {
64 return oop(addr+1)->size() + 1;
65 }
66
67 inline oop make_oop(HeapWord* addr) const {
68 return oop(addr+1);
69 }
70
71 inline oop compact_oop(HeapWord* addr) const {
72 return oop(addr + 1);
73 }
74
75 public:
76 static size_t RegionSizeBytes;
77 static size_t RegionSizeShift;
78
79 private:
80 int _region_number;
81 volatile size_t liveData;
82 MemRegion reserved;
83 bool _is_in_collection_set;
84
85 bool _humongous_start;
86 bool _humongous_continuation;
87
88 #ifdef ASSERT
89 int _mem_protection_level;
90 #endif
91
92 public:
93 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
94
95 jint initialize_heap_region(HeapWord* start, size_t regionSize, int index);
96
97
98 int region_number() const;
99
100 // Roll back the previous allocation of an object with specified size.
101 // Returns TRUE when successful, FALSE if not successful or not supported.
102 bool rollback_allocation(uint size);
103
104 void clearLiveData();
105 void setLiveData(size_t s);
106 void increase_live_data(size_t s);
107
108 size_t getLiveData() const;
109
110 void print_on(outputStream* st) const;
111
112 size_t garbage() const;
113
114 void recycle();
115 void reset();
116
117 void oop_iterate_skip_unreachable(ExtendedOopClosure* cl, bool skip_unreachable_objects);
118
119 void object_iterate_interruptible(ObjectClosure* blk, bool allow_cancel);
120
121 HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
122
123 HeapWord* block_start_const(const void* p) const;
124
125 // Just before GC we need to fill the current region.
126 void fill_region();
127
128 bool is_in_collection_set() const;
129
130 void set_is_in_collection_set(bool b);
131
132 void set_humongous_start(bool start);
133 void set_humongous_continuation(bool continuation);
134
135 bool is_humongous() const;
136 bool is_humongous_start() const;
137 bool is_humongous_continuation() const;
138
139 #ifdef ASSERT
140 void memProtectionOn();
141 void memProtectionOff();
142 #endif
143
144 static ByteSize is_in_collection_set_offset();
145 // The following are for humongous regions. We need to save the
146 markOop saved_mark_word;
147 void save_mark_word(oop obj) {saved_mark_word = obj->mark();}
148 markOop mark_word() {return saved_mark_word;}
149
150 virtual CompactibleSpace* next_compaction_space() const;
151
152 // Override for scan_and_forward support.
153 void prepare_for_compaction(CompactPoint* cp);
154 void adjust_pointers();
155 void compact();
156
157 private:
158 void do_reset();
159
160 };
161
162
163
164 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP