1 /*
2 * Copyright Amazon.com Inc. 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_SHENANDOAH_SHENANDOAHGENERATION_HPP
26 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHGENERATION_HPP
27
28 #include "memory/allocation.hpp"
29 #include "gc/shenandoah/heuristics/shenandoahOldHeuristics.hpp"
30 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp"
31 #include "gc/shenandoah/shenandoahGenerationType.hpp"
32 #include "gc/shenandoah/shenandoahLock.hpp"
33 #include "gc/shenandoah/shenandoahMarkingContext.hpp"
34
35 class ShenandoahHeapRegion;
36 class ShenandoahHeapRegionClosure;
37 class ShenandoahReferenceProcessor;
38 class ShenandoahHeap;
39 class ShenandoahMode;
40
41 class ShenandoahGeneration : public CHeapObj<mtGC>, public ShenandoahSpaceInfo {
42 friend class VMStructs;
43 private:
44 ShenandoahGenerationType const _type;
45
46 // Marking task queues and completeness
47 ShenandoahObjToScanQueueSet* _task_queues;
48 ShenandoahSharedFlag _is_marking_complete;
49
50 ShenandoahReferenceProcessor* const _ref_processor;
51
52 size_t _affiliated_region_count;
53
54 // How much free memory is left in the last region of humongous objects.
55 // This is _not_ included in used, but it _is_ deducted from available,
56 // which gives the heuristics a more accurate view of how much memory remains
57 // for allocation. This figure is also included the heap status logging.
58 // The units are bytes. The value is only changed on a safepoint or under the
59 // heap lock.
60 size_t _humongous_waste;
61
62 protected:
63 // Usage
64
65 volatile size_t _used;
66 volatile size_t _bytes_allocated_since_gc_start;
67 size_t _max_capacity;
68 size_t _soft_max_capacity;
69
70 ShenandoahHeuristics* _heuristics;
71
72 private:
73 // Compute evacuation budgets prior to choosing collection set.
74 void compute_evacuation_budgets(ShenandoahHeap* heap,
75 bool* preselected_regions,
76 ShenandoahCollectionSet* collection_set,
77 size_t& consumed_by_advance_promotion);
78
79 // Adjust evacuation budgets after choosing collection set.
80 void adjust_evacuation_budgets(ShenandoahHeap* heap,
81 ShenandoahCollectionSet* collection_set,
82 size_t consumed_by_advance_promotion);
83
84 // Preselect for inclusion into the collection set regions whose age is
85 // at or above tenure age and which contain more than ShenandoahOldGarbageThreshold
86 // amounts of garbage.
87 //
88 // Returns bytes of old-gen memory consumed by selected aged regions
89 size_t select_aged_regions(size_t old_available,
90 size_t num_regions, bool
91 candidate_regions_for_promotion_by_copy[]);
92
93 size_t available(size_t capacity) const;
94
95 public:
96 ShenandoahGeneration(ShenandoahGenerationType type,
97 uint max_workers,
98 size_t max_capacity,
99 size_t soft_max_capacity);
100 ~ShenandoahGeneration();
101
102 bool is_young() const { return _type == YOUNG; }
103 bool is_old() const { return _type == OLD; }
104 bool is_global() const { return _type == GLOBAL_GEN || _type == GLOBAL_NON_GEN; }
105
106 inline ShenandoahGenerationType type() const { return _type; }
107
108 inline ShenandoahHeuristics* heuristics() const { return _heuristics; }
109
110 ShenandoahReferenceProcessor* ref_processor() { return _ref_processor; }
111
112 virtual ShenandoahHeuristics* initialize_heuristics(ShenandoahMode* gc_mode);
113
114 size_t soft_max_capacity() const override { return _soft_max_capacity; }
115 size_t max_capacity() const override { return _max_capacity; }
116 virtual size_t used_regions() const;
117 virtual size_t used_regions_size() const;
118 virtual size_t free_unaffiliated_regions() const;
119 size_t used() const override { return _used; }
120 size_t available() const override;
121 size_t available_with_reserve() const;
122
123 // Returns the memory available based on the _soft_ max heap capacity (soft_max_heap - used).
124 // The soft max heap size may be adjusted lower than the max heap size to cause the trigger
125 // to believe it has less memory available than is _really_ available. Lowering the soft
126 // max heap size will cause the adaptive heuristic to run more frequent cycles.
127 size_t soft_available() const override;
128
129 size_t bytes_allocated_since_gc_start() const override;
130 void reset_bytes_allocated_since_gc_start();
131 void increase_allocated(size_t bytes);
132
133 // These methods change the capacity of the region by adding or subtracting the given number of bytes from the current
134 // capacity.
135 void increase_capacity(size_t increment);
136 void decrease_capacity(size_t decrement);
137
138 void set_soft_max_capacity(size_t soft_max_capacity) {
139 _soft_max_capacity = soft_max_capacity;
140 }
141
142 void log_status(const char* msg) const;
143
144 // Used directly by FullGC
145 void reset_mark_bitmap();
146
147 // Used by concurrent and degenerated GC to reset remembered set.
148 void swap_remembered_set();
149
150 // Update the read cards with the state of the write table (write table is not cleared).
151 void merge_write_table();
152
153 // Called before init mark, expected to prepare regions for marking.
154 virtual void prepare_gc();
155
156 // Called during final mark, chooses collection set, rebuilds free set.
157 virtual void prepare_regions_and_collection_set(bool concurrent);
158
159 // Cancel marking (used by Full collect and when cancelling cycle).
160 virtual void cancel_marking();
161
162 // Return true if this region is affiliated with this generation.
163 virtual bool contains(ShenandoahHeapRegion* region) const = 0;
164
165 // Return true if this object is affiliated with this generation.
166 virtual bool contains(oop obj) const = 0;
167
168 // Apply closure to all regions affiliated with this generation.
169 virtual void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* cl) = 0;
170
171 // Apply closure to all regions affiliated with this generation (single threaded).
172 virtual void heap_region_iterate(ShenandoahHeapRegionClosure* cl) = 0;
173
174 // This is public to support cancellation of marking when a Full cycle is started.
175 virtual void set_concurrent_mark_in_progress(bool in_progress) = 0;
176
177 // Check the bitmap only for regions belong to this generation.
178 bool is_bitmap_clear();
179
180 // We need to track the status of marking for different generations.
181 bool is_mark_complete();
182 virtual void set_mark_complete();
183 virtual void set_mark_incomplete();
184
185 ShenandoahMarkingContext* complete_marking_context();
186
187 // Task queues
188 ShenandoahObjToScanQueueSet* task_queues() const { return _task_queues; }
189 virtual void reserve_task_queues(uint workers);
190 virtual ShenandoahObjToScanQueueSet* old_gen_task_queues() const;
191
192 // Scan remembered set at start of concurrent young-gen marking.
193 void scan_remembered_set(bool is_concurrent);
194
195 // Return the updated value of affiliated_region_count
196 size_t increment_affiliated_region_count();
197
198 // Return the updated value of affiliated_region_count
199 size_t decrement_affiliated_region_count();
200
201 // Return the updated value of affiliated_region_count
202 size_t increase_affiliated_region_count(size_t delta);
203
204 // Return the updated value of affiliated_region_count
205 size_t decrease_affiliated_region_count(size_t delta);
206
207 void establish_usage(size_t num_regions, size_t num_bytes, size_t humongous_waste);
208
209 void increase_used(size_t bytes);
210 void decrease_used(size_t bytes);
211
212 void increase_humongous_waste(size_t bytes);
213 void decrease_humongous_waste(size_t bytes);
214 size_t get_humongous_waste() const { return _humongous_waste; }
215
216 virtual bool is_concurrent_mark_in_progress() = 0;
217 void confirm_heuristics_mode();
218
219 virtual void record_success_concurrent(bool abbreviated);
220 virtual void record_success_degenerated();
221 };
222
223 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHGENERATION_HPP