1 /*
2 * Copyright (c) 2001, 2016, 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
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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/cardTableRS.hpp"
29 #include "gc/shared/generationSpec.hpp"
30 #include "memory/allocation.hpp"
31 #include "utilities/macros.hpp"
32
33 // This class (or more correctly, subtypes of this class)
34 // are used to define global garbage collector attributes.
35 // This includes initialization of generations and any other
36 // shared resources they may need.
37 //
38 // In general, all flag adjustment and validation should be
39 // done in initialize_flags(), which is called prior to
40 // initialize_size_info().
41 //
42 // This class is not fully developed yet. As more collector(s)
43 // are added, it is expected that we will come across further
44 // behavior that requires global attention. The correct place
45 // to deal with those issues is this class.
46
47 // Forward declarations.
48 class GenCollectorPolicy;
49 class AdaptiveSizePolicy;
50 #if INCLUDE_ALL_GCS
51 class ConcurrentMarkSweepPolicy;
52 class G1CollectorPolicy;
53 #endif // INCLUDE_ALL_GCS
54
55 class GCPolicyCounters;
56 class MarkSweepPolicy;
57
58 class CollectorPolicy : public CHeapObj<mtGC> {
59 protected:
60 virtual void initialize_alignments() = 0;
61 virtual void initialize_flags();
62 virtual void initialize_size_info();
63
64 DEBUG_ONLY(virtual void assert_flags();)
65 DEBUG_ONLY(virtual void assert_size_info();)
66
67 size_t _initial_heap_byte_size;
68 size_t _max_heap_byte_size;
69 size_t _min_heap_byte_size;
70
71 size_t _space_alignment;
72 size_t _heap_alignment;
73
74 // The sizing of the heap is controlled by a sizing policy.
75 AdaptiveSizePolicy* _size_policy;
76
77 // Set to true when policy wants soft refs cleared.
78 // Reset to false by gc after it clears all soft refs.
79 bool _should_clear_all_soft_refs;
80
81 // Set to true by the GC if the just-completed gc cleared all
82 // softrefs. This is set to true whenever a gc clears all softrefs, and
83 // set to false each time gc returns to the mutator. For example, in the
84 // ParallelScavengeHeap case the latter would be done toward the end of
85 // mem_allocate() where it returns op.result()
86 bool _all_soft_refs_clear;
87
88 CollectorPolicy();
89
90 public:
91 virtual void initialize_all() {
92 initialize_alignments();
93 initialize_flags();
94 initialize_size_info();
95 }
96
97 // Return maximum heap alignment that may be imposed by the policy.
98 static size_t compute_heap_alignment();
99
100 size_t space_alignment() { return _space_alignment; }
101 size_t heap_alignment() { return _heap_alignment; }
102
103 size_t initial_heap_byte_size() { return _initial_heap_byte_size; }
104 size_t max_heap_byte_size() { return _max_heap_byte_size; }
105 size_t min_heap_byte_size() { return _min_heap_byte_size; }
106
107 AdaptiveSizePolicy* size_policy() { return _size_policy; }
108 bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }
109 void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }
110 // Returns the current value of _should_clear_all_soft_refs.
111 // _should_clear_all_soft_refs is set to false as a side effect.
112 bool use_should_clear_all_soft_refs(bool v);
113 bool all_soft_refs_clear() { return _all_soft_refs_clear; }
114 void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }
115
116 // Called by the GC after Soft Refs have been cleared to indicate
117 // that the request in _should_clear_all_soft_refs has been fulfilled.
118 void cleared_all_soft_refs();
119
120 // Identification methods.
121 virtual GenCollectorPolicy* as_generation_policy() { return NULL; }
122 virtual MarkSweepPolicy* as_mark_sweep_policy() { return NULL; }
123 #if INCLUDE_ALL_GCS
124 virtual ConcurrentMarkSweepPolicy* as_concurrent_mark_sweep_policy() { return NULL; }
125 #endif // INCLUDE_ALL_GCS
126 // Note that these are not virtual.
127 bool is_generation_policy() { return as_generation_policy() != NULL; }
128 bool is_mark_sweep_policy() { return as_mark_sweep_policy() != NULL; }
129 #if INCLUDE_ALL_GCS
130 bool is_concurrent_mark_sweep_policy() { return as_concurrent_mark_sweep_policy() != NULL; }
131 #else // INCLUDE_ALL_GCS
132 bool is_concurrent_mark_sweep_policy() { return false; }
133 #endif // INCLUDE_ALL_GCS
134
135 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
136 size_t size,
137 Metaspace::MetadataType mdtype);
138 };
139
140 class ClearedAllSoftRefs : public StackObj {
141 bool _clear_all_soft_refs;
142 CollectorPolicy* _collector_policy;
143 public:
144 ClearedAllSoftRefs(bool clear_all_soft_refs,
145 CollectorPolicy* collector_policy) :
146 _clear_all_soft_refs(clear_all_soft_refs),
147 _collector_policy(collector_policy) {}
148
149 ~ClearedAllSoftRefs() {
150 if (_clear_all_soft_refs) {
151 _collector_policy->cleared_all_soft_refs();
152 }
153 }
154 };
155
156 class GenCollectorPolicy : public CollectorPolicy {
157 friend class TestGenCollectorPolicy;
158 friend class VMStructs;
159 protected:
160 size_t _min_young_size;
161 size_t _initial_young_size;
162 size_t _max_young_size;
163 size_t _min_old_size;
164 size_t _initial_old_size;
165 size_t _max_old_size;
166
167 // _gen_alignment and _space_alignment will have the same value most of the
168 // time. When using large pages they can differ.
169 size_t _gen_alignment;
170
171 GenerationSpec* _young_gen_spec;
172 GenerationSpec* _old_gen_spec;
173
174 GCPolicyCounters* _gc_policy_counters;
175
176 // Return true if an allocation should be attempted in the older generation
177 // if it fails in the younger generation. Return false, otherwise.
178 virtual bool should_try_older_generation_allocation(size_t word_size) const;
179
180 void initialize_flags();
181 void initialize_size_info();
182
183 DEBUG_ONLY(void assert_flags();)
184 DEBUG_ONLY(void assert_size_info();)
185
186 // Try to allocate space by expanding the heap.
187 virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);
188
189 // Compute max heap alignment.
190 size_t compute_max_alignment();
191
192 // Scale the base_size by NewRatio according to
193 // result = base_size / (NewRatio + 1)
194 // and align by min_alignment()
195 size_t scale_by_NewRatio_aligned(size_t base_size);
196
197 // Bound the value by the given maximum minus the min_alignment.
198 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);
199
200 public:
201 GenCollectorPolicy();
202
203 // Accessors
204 size_t min_young_size() { return _min_young_size; }
205 size_t initial_young_size() { return _initial_young_size; }
206 size_t max_young_size() { return _max_young_size; }
207 size_t gen_alignment() { return _gen_alignment; }
208 size_t min_old_size() { return _min_old_size; }
209 size_t initial_old_size() { return _initial_old_size; }
210 size_t max_old_size() { return _max_old_size; }
211
212 GenerationSpec* young_gen_spec() const {
213 assert(_young_gen_spec != NULL, "_young_gen_spec should have been initialized");
214 return _young_gen_spec;
215 }
216
217 GenerationSpec* old_gen_spec() const {
218 assert(_old_gen_spec != NULL, "_old_gen_spec should have been initialized");
219 return _old_gen_spec;
220 }
221
222 // Performance Counter support
223 GCPolicyCounters* counters() { return _gc_policy_counters; }
224
225 // Create the jstat counters for the GC policy.
226 virtual void initialize_gc_policy_counters() = 0;
227
228 virtual GenCollectorPolicy* as_generation_policy() { return this; }
229
230 virtual void initialize_generations() { };
231
232 virtual void initialize_all() {
233 CollectorPolicy::initialize_all();
234 initialize_generations();
235 }
236
237 size_t young_gen_size_lower_bound();
238
239 size_t old_gen_size_lower_bound();
240
241 HeapWord* mem_allocate_work(size_t size,
242 bool is_tlab,
243 bool* gc_overhead_limit_was_exceeded);
244
245 HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab);
246
247 // Adaptive size policy
248 virtual void initialize_size_policy(size_t init_eden_size,
249 size_t init_promo_size,
250 size_t init_survivor_size);
251 };
252
253 class MarkSweepPolicy : public GenCollectorPolicy {
254 protected:
255 void initialize_alignments();
256 void initialize_generations();
257
258 public:
259 MarkSweepPolicy() {}
260
261 MarkSweepPolicy* as_mark_sweep_policy() { return this; }
262
263 void initialize_gc_policy_counters();
264 };
265
266 #endif // SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP