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.
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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/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 // The sizing of the heap is controlled by a sizing policy.
76 AdaptiveSizePolicy* _size_policy;
77
78 // Set to true when policy wants soft refs cleared.
79 // Reset to false by gc after it clears all soft refs.
80 bool _should_clear_all_soft_refs;
81
82 // Set to true by the GC if the just-completed gc cleared all
83 // softrefs. This is set to true whenever a gc clears all softrefs, and
84 // set to false each time gc returns to the mutator. For example, in the
85 // ParallelScavengeHeap case the latter would be done toward the end of
86 // mem_allocate() where it returns op.result()
87 bool _all_soft_refs_clear;
88
89 CollectorPolicy();
90
91 public:
92 virtual void initialize_all() {
93 initialize_alignments();
94 initialize_flags();
95 initialize_size_info();
96 }
97
98 // Return maximum heap alignment that may be imposed by the policy.
99 static size_t compute_heap_alignment();
100
101 size_t space_alignment() { return _space_alignment; }
102 size_t heap_alignment() { return _heap_alignment; }
103
104 size_t initial_heap_byte_size() { return _initial_heap_byte_size; }
105 size_t max_heap_byte_size() { return _max_heap_byte_size; }
106 size_t min_heap_byte_size() { return _min_heap_byte_size; }
107
108 AdaptiveSizePolicy* size_policy() { return _size_policy; }
109 bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }
110 void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }
111 // Returns the current value of _should_clear_all_soft_refs.
112 // _should_clear_all_soft_refs is set to false as a side effect.
113 bool use_should_clear_all_soft_refs(bool v);
114 bool all_soft_refs_clear() { return _all_soft_refs_clear; }
115 void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }
116
117 // Called by the GC after Soft Refs have been cleared to indicate
118 // that the request in _should_clear_all_soft_refs has been fulfilled.
119 void cleared_all_soft_refs();
120
121 // Identification methods.
122 virtual GenCollectorPolicy* as_generation_policy() { return NULL; }
123 virtual MarkSweepPolicy* as_mark_sweep_policy() { return NULL; }
124 #if INCLUDE_ALL_GCS
125 virtual ConcurrentMarkSweepPolicy* as_concurrent_mark_sweep_policy() { return NULL; }
126 #endif // INCLUDE_ALL_GCS
127 // Note that these are not virtual.
128 bool is_generation_policy() { return as_generation_policy() != NULL; }
129 bool is_mark_sweep_policy() { return as_mark_sweep_policy() != NULL; }
130 #if INCLUDE_ALL_GCS
131 bool is_concurrent_mark_sweep_policy() { return as_concurrent_mark_sweep_policy() != NULL; }
132 #else // INCLUDE_ALL_GCS
133 bool is_concurrent_mark_sweep_policy() { return false; }
134 #endif // INCLUDE_ALL_GCS
135
136
137 virtual CardTableRS* create_rem_set(MemRegion reserved);
138
139 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
140 size_t size,
141 Metaspace::MetadataType mdtype);
142 };
143
144 class ClearedAllSoftRefs : public StackObj {
145 bool _clear_all_soft_refs;
146 CollectorPolicy* _collector_policy;
147 public:
148 ClearedAllSoftRefs(bool clear_all_soft_refs,
149 CollectorPolicy* collector_policy) :
150 _clear_all_soft_refs(clear_all_soft_refs),
151 _collector_policy(collector_policy) {}
152
153 ~ClearedAllSoftRefs() {
154 if (_clear_all_soft_refs) {
155 _collector_policy->cleared_all_soft_refs();
156 }
157 }
158
159 bool should_clear() { return _clear_all_soft_refs; }
160 };
161
162 class GenCollectorPolicy : public CollectorPolicy {
163 friend class TestGenCollectorPolicy;
164 friend class VMStructs;
165 protected:
166 size_t _min_young_size;
167 size_t _initial_young_size;
168 size_t _max_young_size;
169 size_t _min_old_size;
170 size_t _initial_old_size;
171 size_t _max_old_size;
172
173 // _gen_alignment and _space_alignment will have the same value most of the
174 // time. When using large pages they can differ.
175 size_t _gen_alignment;
176
177 GenerationSpec* _young_gen_spec;
178 GenerationSpec* _old_gen_spec;
179
180 GCPolicyCounters* _gc_policy_counters;
181
182 // Return true if an allocation should be attempted in the older generation
183 // if it fails in the younger generation. Return false, otherwise.
184 virtual bool should_try_older_generation_allocation(size_t word_size) const;
185
186 void initialize_flags();
187 void initialize_size_info();
188
189 DEBUG_ONLY(void assert_flags();)
190 DEBUG_ONLY(void assert_size_info();)
191
192 // Try to allocate space by expanding the heap.
193 virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);
194
195 // Compute max heap alignment.
196 size_t compute_max_alignment();
197
198 // Scale the base_size by NewRatio according to
199 // result = base_size / (NewRatio + 1)
200 // and align by min_alignment()
201 size_t scale_by_NewRatio_aligned(size_t base_size);
202
203 // Bound the value by the given maximum minus the min_alignment.
204 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);
205
206 public:
207 GenCollectorPolicy();
208
209 // Accessors
210 size_t min_young_size() { return _min_young_size; }
211 size_t initial_young_size() { return _initial_young_size; }
212 size_t max_young_size() { return _max_young_size; }
213 size_t gen_alignment() { return _gen_alignment; }
214 size_t min_old_size() { return _min_old_size; }
215 size_t initial_old_size() { return _initial_old_size; }
216 size_t max_old_size() { return _max_old_size; }
217
218 GenerationSpec* young_gen_spec() const {
219 assert(_young_gen_spec != NULL, "_young_gen_spec should have been initialized");
220 return _young_gen_spec;
221 }
222
223 GenerationSpec* old_gen_spec() const {
224 assert(_old_gen_spec != NULL, "_old_gen_spec should have been initialized");
225 return _old_gen_spec;
226 }
227
228 // Performance Counter support
229 GCPolicyCounters* counters() { return _gc_policy_counters; }
230
231 // Create the jstat counters for the GC policy.
232 virtual void initialize_gc_policy_counters() = 0;
233
234 virtual GenCollectorPolicy* as_generation_policy() { return this; }
235
236 virtual void initialize_generations() { };
237
238 virtual void initialize_all() {
239 CollectorPolicy::initialize_all();
240 initialize_generations();
241 }
242
243 size_t young_gen_size_lower_bound();
244
245 size_t old_gen_size_lower_bound();
246
247 HeapWord* mem_allocate_work(size_t size,
248 bool is_tlab,
249 bool* gc_overhead_limit_was_exceeded);
250
251 HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab);
252
253 // Adaptive size policy
254 virtual void initialize_size_policy(size_t init_eden_size,
255 size_t init_promo_size,
256 size_t init_survivor_size);
257 };
258
259 class MarkSweepPolicy : public GenCollectorPolicy {
260 protected:
261 void initialize_alignments();
262 void initialize_generations();
263
264 public:
265 MarkSweepPolicy() {}
266
267 MarkSweepPolicy* as_mark_sweep_policy() { return this; }
268
269 void initialize_gc_policy_counters();
270 };
271
272 #endif // SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP