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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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).
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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 protected:
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 const char* const _name; // Name of this generation.
48
49 // Performance Counters
50 PSGenerationCounters* _gen_counters;
51 SpaceCounters* _space_counters;
52
53 // Sizing information, in bytes, set in constructor
54 const size_t _init_gen_size;
55 const size_t _min_gen_size;
56 const size_t _max_gen_size;
57
58 // Used when initializing the _name field.
59 static inline const char* old_gen_name();
60
61 #ifdef ASSERT
62 void assert_block_in_covered_region(MemRegion new_memregion) {
63 // Explictly capture current covered_region in a local
64 MemRegion covered_region = this->start_array()->covered_region();
65 assert(covered_region.contains(new_memregion),
66 "new region is not in covered_region [ " PTR_FORMAT ", " PTR_FORMAT " ], "
67 "new region [ " PTR_FORMAT ", " PTR_FORMAT " ], "
68 "object space [ " PTR_FORMAT ", " PTR_FORMAT " ]",
69 p2i(covered_region.start()),
70 p2i(covered_region.end()),
71 p2i(new_memregion.start()),
72 p2i(new_memregion.end()),
73 p2i(this->object_space()->used_region().start()),
74 p2i(this->object_space()->used_region().end()));
75 }
76 #endif
77
78 HeapWord* allocate_noexpand(size_t word_size) {
79 // We assume the heap lock is held here.
80 assert_locked_or_safepoint(Heap_lock);
81 HeapWord* res = object_space()->allocate(word_size);
82 if (res != NULL) {
83 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size)));
84 _start_array.allocate_block(res);
85 }
86 return res;
87 }
88
89 // Support for MT garbage collection. CAS allocation is lower overhead than grabbing
90 // and releasing the heap lock, which is held during gc's anyway. This method is not
91 // safe for use at the same time as allocate_noexpand()!
92 HeapWord* cas_allocate_noexpand(size_t word_size) {
93 assert(SafepointSynchronize::is_at_safepoint(), "Must only be called at safepoint");
94 HeapWord* res = object_space()->cas_allocate(word_size);
95 if (res != NULL) {
96 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size)));
97 _start_array.allocate_block(res);
98 }
99 return res;
100 }
101
102 // Support for MT garbage collection. See above comment.
103 HeapWord* cas_allocate(size_t word_size) {
104 HeapWord* res = cas_allocate_noexpand(word_size);
105 return (res == NULL) ? expand_and_cas_allocate(word_size) : res;
106 }
107
108 HeapWord* expand_and_allocate(size_t word_size);
109 HeapWord* expand_and_cas_allocate(size_t word_size);
110 void expand(size_t bytes);
111 bool expand_by(size_t bytes);
112 bool expand_to_reserved();
113
114 void shrink(size_t bytes);
115
116 void post_resize();
117
118 public:
119 // Initialize the generation.
120 PSOldGen(ReservedSpace rs, size_t alignment,
121 size_t initial_size, size_t min_size, size_t max_size,
122 const char* perf_data_name, int level);
123
124 PSOldGen(size_t initial_size, size_t min_size, size_t max_size,
125 const char* perf_data_name, int level);
126
127 virtual void initialize(ReservedSpace rs, size_t alignment,
128 const char* perf_data_name, int level);
129 void initialize_virtual_space(ReservedSpace rs, size_t alignment);
130 virtual void initialize_work(const char* perf_data_name, int level);
131 virtual void initialize_performance_counters(const char* perf_data_name, int level);
132
133 MemRegion reserved() const { return _reserved; }
134 virtual size_t max_gen_size() { return _max_gen_size; }
135 size_t min_gen_size() { return _min_gen_size; }
136
137 // Returns limit on the maximum size of the generation. This
138 // is the same as _max_gen_size for PSOldGen but need not be
139 // for a derived class.
140 virtual size_t gen_size_limit();
141
142 bool is_in(const void* p) const {
143 return _virtual_space->contains((void *)p);
144 }
145
146 bool is_in_reserved(const void* p) const {
147 return reserved().contains(p);
148 }
149
150 MutableSpace* object_space() const { return _object_space; }
151 ObjectStartArray* start_array() { return &_start_array; }
152 PSVirtualSpace* virtual_space() const { return _virtual_space;}
153
154 // Has the generation been successfully allocated?
155 bool is_allocated();
156
157 // Size info
158 size_t capacity_in_bytes() const { return object_space()->capacity_in_bytes(); }
159 size_t used_in_bytes() const { return object_space()->used_in_bytes(); }
160 size_t free_in_bytes() const { return object_space()->free_in_bytes(); }
161
162 size_t capacity_in_words() const { return object_space()->capacity_in_words(); }
163 size_t used_in_words() const { return object_space()->used_in_words(); }
164 size_t free_in_words() const { return object_space()->free_in_words(); }
165
166 // Includes uncommitted memory
167 size_t contiguous_available() const;
168
169 bool is_maximal_no_gc() const {
170 return virtual_space()->uncommitted_size() == 0;
171 }
172
173 // Calculating new sizes
174 void resize(size_t desired_free_space);
175
176 // Allocation. We report all successful allocations to the size policy
177 // Note that the perm gen does not use this method, and should not!
178 HeapWord* allocate(size_t word_size);
179
180 // Iteration.
181 void oop_iterate(OopIterateClosure* cl) { object_space()->oop_iterate(cl); }
182 void object_iterate(ObjectClosure* cl) { object_space()->object_iterate(cl); }
183
184 // Debugging - do not use for time critical operations
185 virtual void print() const;
186 virtual void print_on(outputStream* st) const;
187
188 void verify();
189 void verify_object_start_array();
190
191 // These should not used
192 virtual void reset_after_change();
193
194 // These should not used
195 virtual size_t available_for_expansion();
196 virtual size_t available_for_contraction();
197
198 void space_invariants() PRODUCT_RETURN;
199
200 // Performance Counter support
201 void update_counters();
202
203 // Printing support
204 virtual const char* name() const { return _name; }
205
206 // Debugging support
207 // Save the tops of all spaces for later use during mangling.
208 void record_spaces_top() PRODUCT_RETURN;
209 };
210
211 #endif // SHARE_GC_PARALLEL_PSOLDGEN_HPP