1 /*
2 * Copyright (c) 2001, 2020, 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
21 * questions.
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23 */
24
25 #ifndef SHARE_GC_PARALLEL_PSOLDGEN_HPP
26 #define SHARE_GC_PARALLEL_PSOLDGEN_HPP
27
28 #include "gc/parallel/mutableSpace.hpp"
29 #include "gc/parallel/objectStartArray.hpp"
30 #include "gc/parallel/psGenerationCounters.hpp"
31 #include "gc/parallel/psVirtualspace.hpp"
32 #include "gc/parallel/spaceCounters.hpp"
33 #include "runtime/safepoint.hpp"
34
35 class PSOldGen : public CHeapObj<mtGC> {
36 friend class VMStructs;
37 friend class PSPromotionManager; // Uses the cas_allocate methods
38 friend class ParallelScavengeHeap;
39 friend class AdjoiningGenerations;
40
41 private:
42 MemRegion _reserved; // Used for simple containment tests
43 PSVirtualSpace* _virtual_space; // Controls mapping and unmapping of virtual mem
44 ObjectStartArray _start_array; // Keeps track of where objects start in a 512b block
45 MutableSpace* _object_space; // Where all the objects live
46
47 // Performance Counters
48 PSGenerationCounters* _gen_counters;
49 SpaceCounters* _space_counters;
50
51 // Sizing information, in bytes, set in constructor
52 const size_t _min_gen_size;
53 const size_t _max_gen_size;
54
55 #ifdef ASSERT
56 void assert_block_in_covered_region(MemRegion new_memregion) {
57 // Explictly capture current covered_region in a local
58 MemRegion covered_region = this->start_array()->covered_region();
59 assert(covered_region.contains(new_memregion),
60 "new region is not in covered_region [ " PTR_FORMAT ", " PTR_FORMAT " ], "
61 "new region [ " PTR_FORMAT ", " PTR_FORMAT " ], "
62 "object space [ " PTR_FORMAT ", " PTR_FORMAT " ]",
63 p2i(covered_region.start()),
64 p2i(covered_region.end()),
65 p2i(new_memregion.start()),
66 p2i(new_memregion.end()),
67 p2i(this->object_space()->used_region().start()),
68 p2i(this->object_space()->used_region().end()));
69 }
70 #endif
71
72 HeapWord* allocate_noexpand(size_t word_size) {
73 // We assume the heap lock is held here.
74 assert_locked_or_safepoint(Heap_lock);
75 HeapWord* res = object_space()->allocate(word_size);
76 if (res != NULL) {
77 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size)));
78 _start_array.allocate_block(res);
79 }
80 return res;
81 }
82
83 // Support for MT garbage collection. CAS allocation is lower overhead than grabbing
84 // and releasing the heap lock, which is held during gc's anyway. This method is not
85 // safe for use at the same time as allocate_noexpand()!
86 HeapWord* cas_allocate_noexpand(size_t word_size) {
87 assert(SafepointSynchronize::is_at_safepoint(), "Must only be called at safepoint");
88 HeapWord* res = object_space()->cas_allocate(word_size);
89 if (res != NULL) {
90 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size)));
91 _start_array.allocate_block(res);
92 }
93 return res;
94 }
95
96 // Support for MT garbage collection. See above comment.
97 HeapWord* cas_allocate(size_t word_size) {
98 HeapWord* res = cas_allocate_noexpand(word_size);
99 return (res == NULL) ? expand_and_cas_allocate(word_size) : res;
100 }
101
102 HeapWord* expand_and_allocate(size_t word_size);
103 HeapWord* expand_and_cas_allocate(size_t word_size);
104 void expand(size_t bytes);
105 bool expand_by(size_t bytes);
106 bool expand_to_reserved();
107
108 void shrink(size_t bytes);
109
110 void post_resize();
111
112 void initialize(ReservedSpace rs, size_t initial_size, size_t alignment,
113 const char* perf_data_name, int level);
114 void initialize_virtual_space(ReservedSpace rs, size_t initial_size, size_t alignment);
115 void initialize_work(const char* perf_data_name, int level);
116 void initialize_performance_counters(const char* perf_data_name, int level);
117
118 public:
119 // Initialize the generation.
120 PSOldGen(ReservedSpace rs, size_t initial_size, size_t min_size,
121 size_t max_size, const char* perf_data_name, int level);
122
123 MemRegion reserved() const { return _reserved; }
124 size_t max_gen_size() const { return _max_gen_size; }
125 size_t min_gen_size() const { return _min_gen_size; }
126
127 bool is_in(const void* p) const {
128 return _virtual_space->contains((void *)p);
129 }
130
131 bool is_in_reserved(const void* p) const {
132 return reserved().contains(p);
133 }
134
135 MutableSpace* object_space() const { return _object_space; }
136 ObjectStartArray* start_array() { return &_start_array; }
137 PSVirtualSpace* virtual_space() const { return _virtual_space;}
138
139 // Has the generation been successfully allocated?
140 bool is_allocated();
141
142 // Size info
143 size_t capacity_in_bytes() const { return object_space()->capacity_in_bytes(); }
144 size_t used_in_bytes() const { return object_space()->used_in_bytes(); }
145 size_t free_in_bytes() const { return object_space()->free_in_bytes(); }
146
147 size_t capacity_in_words() const { return object_space()->capacity_in_words(); }
148 size_t used_in_words() const { return object_space()->used_in_words(); }
149 size_t free_in_words() const { return object_space()->free_in_words(); }
150
151 bool is_maximal_no_gc() const {
152 return virtual_space()->uncommitted_size() == 0;
153 }
154
155 // Calculating new sizes
156 void resize(size_t desired_free_space);
157
158 // Allocation. We report all successful allocations to the size policy
159 // Note that the perm gen does not use this method, and should not!
160 HeapWord* allocate(size_t word_size);
161
162 // Iteration.
163 void oop_iterate(OopIterateClosure* cl) { object_space()->oop_iterate(cl); }
164 void object_iterate(ObjectClosure* cl) { object_space()->object_iterate(cl); }
165
166 // Debugging - do not use for time critical operations
167 void print() const;
168 virtual void print_on(outputStream* st) const;
169
170 void verify();
171 void verify_object_start_array();
172
173 // Performance Counter support
174 void update_counters();
175
176 // Printing support
177 const char* name() const { return "ParOldGen"; }
178
179 // Debugging support
180 // Save the tops of all spaces for later use during mangling.
181 void record_spaces_top() PRODUCT_RETURN;
182 };
183
184 #endif // SHARE_GC_PARALLEL_PSOLDGEN_HPP