1 /*
2 * Copyright (c) 2001, 2018, 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_VM_GC_SHARED_COLLECTORPOLICY_HPP
26 #define SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP
27
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shared/cardTableRS.hpp"
30 #include "gc/shared/generationSpec.hpp"
31 #include "memory/allocation.hpp"
32 #include "utilities/macros.hpp"
33
34 // This class (or more correctly, subtypes of this class)
35 // are used to define global garbage collector attributes.
36 // This includes initialization of generations and any other
37 // shared resources they may need.
38 //
39 // In general, all flag adjustment and validation should be
40 // done in initialize_flags(), which is called prior to
41 // initialize_size_info().
42 //
43 // This class is not fully developed yet. As more collector(s)
44 // are added, it is expected that we will come across further
45 // behavior that requires global attention. The correct place
46 // to deal with those issues is this class.
47
48 // Forward declarations.
49 class GenCollectorPolicy;
50 class AdaptiveSizePolicy;
51 #if INCLUDE_ALL_GCS
52 class ConcurrentMarkSweepPolicy;
53 class G1CollectorPolicy;
54 #endif // INCLUDE_ALL_GCS
55
56 class GCPolicyCounters;
57 class MarkSweepPolicy;
58
59 class CollectorPolicy : public CHeapObj<mtGC> {
60 protected:
61 virtual void initialize_alignments() = 0;
62 virtual void initialize_flags();
63 virtual void initialize_size_info();
64
65 DEBUG_ONLY(virtual void assert_flags();)
66 DEBUG_ONLY(virtual void assert_size_info();)
67
68 size_t _initial_heap_byte_size;
69 size_t _max_heap_byte_size;
70 size_t _min_heap_byte_size;
71
72 size_t _space_alignment;
73 size_t _heap_alignment;
74
75 // Set to true when policy wants soft refs cleared.
76 // Reset to false by gc after it clears all soft refs.
77 bool _should_clear_all_soft_refs;
78
79 // Set to true by the GC if the just-completed gc cleared all
80 // softrefs. This is set to true whenever a gc clears all softrefs, and
81 // set to false each time gc returns to the mutator. For example, in the
82 // ParallelScavengeHeap case the latter would be done toward the end of
83 // mem_allocate() where it returns op.result()
84 bool _all_soft_refs_clear;
85
86 CollectorPolicy();
87
88 public:
89 virtual void initialize_all() {
90 initialize_alignments();
91 initialize_flags();
92 initialize_size_info();
93 }
94
95 // Return maximum heap alignment that may be imposed by the policy.
96 static size_t compute_heap_alignment();
97
98 size_t space_alignment() { return _space_alignment; }
99 size_t heap_alignment() { return _heap_alignment; }
100
101 size_t initial_heap_byte_size() { return _initial_heap_byte_size; }
102 size_t max_heap_byte_size() { return _max_heap_byte_size; }
103 size_t min_heap_byte_size() { return _min_heap_byte_size; }
104
105 bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }
106 void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }
107 // Returns the current value of _should_clear_all_soft_refs.
108 // _should_clear_all_soft_refs is set to false as a side effect.
109 bool use_should_clear_all_soft_refs(bool v);
110 bool all_soft_refs_clear() { return _all_soft_refs_clear; }
111 void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }
112
113 // Called by the GC after Soft Refs have been cleared to indicate
114 // that the request in _should_clear_all_soft_refs has been fulfilled.
115 virtual void cleared_all_soft_refs();
116 };
117
118 class ClearedAllSoftRefs : public StackObj {
119 bool _clear_all_soft_refs;
120 CollectorPolicy* _collector_policy;
121 public:
122 ClearedAllSoftRefs(bool clear_all_soft_refs,
123 CollectorPolicy* collector_policy) :
124 _clear_all_soft_refs(clear_all_soft_refs),
125 _collector_policy(collector_policy) {}
126
127 ~ClearedAllSoftRefs() {
128 if (_clear_all_soft_refs) {
129 _collector_policy->cleared_all_soft_refs();
130 }
131 }
132
133 bool should_clear() { return _clear_all_soft_refs; }
134 };
135
136 class GenCollectorPolicy : public CollectorPolicy {
137 friend class TestGenCollectorPolicy;
138 friend class VMStructs;
139
140 protected:
141 size_t _min_young_size;
142 size_t _initial_young_size;
143 size_t _max_young_size;
144 size_t _min_old_size;
145 size_t _initial_old_size;
146 size_t _max_old_size;
147
148 // _gen_alignment and _space_alignment will have the same value most of the
149 // time. When using large pages they can differ.
150 size_t _gen_alignment;
151
152 GenerationSpec* _young_gen_spec;
153 GenerationSpec* _old_gen_spec;
154
155 GCPolicyCounters* _gc_policy_counters;
156
157 // The sizing of the heap is controlled by a sizing policy.
158 AdaptiveSizePolicy* _size_policy;
159
160 void initialize_flags();
161 void initialize_size_info();
162
163 DEBUG_ONLY(void assert_flags();)
164 DEBUG_ONLY(void assert_size_info();)
165
166 // Compute max heap alignment.
167 size_t compute_max_alignment();
168
169 // Scale the base_size by NewRatio according to
170 // result = base_size / (NewRatio + 1)
171 // and align by min_alignment()
172 size_t scale_by_NewRatio_aligned(size_t base_size);
173
174 // Bound the value by the given maximum minus the min_alignment.
175 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);
176
177 public:
178 GenCollectorPolicy();
179
180 // Accessors
181 size_t min_young_size() { return _min_young_size; }
182 size_t initial_young_size() { return _initial_young_size; }
183 size_t max_young_size() { return _max_young_size; }
184 size_t gen_alignment() { return _gen_alignment; }
185 size_t min_old_size() { return _min_old_size; }
186 size_t initial_old_size() { return _initial_old_size; }
187 size_t max_old_size() { return _max_old_size; }
188
189 GenerationSpec* young_gen_spec() const {
190 assert(_young_gen_spec != NULL, "_young_gen_spec should have been initialized");
191 return _young_gen_spec;
192 }
193
194 GenerationSpec* old_gen_spec() const {
195 assert(_old_gen_spec != NULL, "_old_gen_spec should have been initialized");
196 return _old_gen_spec;
197 }
198
199 // Performance Counter support
200 GCPolicyCounters* counters() { return _gc_policy_counters; }
201
202 // Create the jstat counters for the GC policy.
203 virtual void initialize_gc_policy_counters() = 0;
204
205 virtual void initialize_generations() { };
206
207 virtual void initialize_all() {
208 CollectorPolicy::initialize_all();
209 initialize_generations();
210 }
211
212 size_t young_gen_size_lower_bound();
213
214 size_t old_gen_size_lower_bound();
215
216 // Adaptive size policy
217 AdaptiveSizePolicy* size_policy() { return _size_policy; }
218
219 virtual void initialize_size_policy(size_t init_eden_size,
220 size_t init_promo_size,
221 size_t init_survivor_size);
222
223 virtual void cleared_all_soft_refs();
224
225 };
226
227 class MarkSweepPolicy : public GenCollectorPolicy {
228 protected:
229 void initialize_alignments();
230 void initialize_generations();
231
232 public:
233 MarkSweepPolicy() {}
234
235 void initialize_gc_policy_counters();
236 };
237
238 #endif // SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP