1 /*
2 * Copyright (c) 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
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP
26 #define SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP
27
28 #include "gc/g1/g1CollectorState.hpp"
29 #include "gc/g1/g1GCPhaseTimes.hpp"
30 #include "gc/g1/g1InCSetState.hpp"
31 #include "gc/g1/g1InitialMarkToMixedTimeTracker.hpp"
32 #include "gc/g1/g1MMUTracker.hpp"
33 #include "gc/g1/g1Predictions.hpp"
34 #include "gc/g1/g1Policy.hpp"
35 #include "gc/g1/g1YoungGenSizer.hpp"
36 #include "gc/shared/gcCause.hpp"
37 #include "utilities/pair.hpp"
38
39 class HeapRegion;
40 class G1CollectionSet;
41 class CollectionSetChooser;
42 class G1IHOPControl;
43 class G1Analytics;
44 class G1SurvivorRegions;
45 class G1YoungGenSizer;
46 class GCPolicyCounters;
47
48 class G1DefaultPolicy: public G1Policy {
49 private:
50
51 static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
52 // Update the IHOP control with necessary statistics.
53 void update_ihop_prediction(double mutator_time_s,
54 size_t mutator_alloc_bytes,
55 size_t young_gen_size);
56 void report_ihop_statistics();
57
58 G1Predictions _predictor;
59 G1Analytics* _analytics;
60 G1MMUTracker* _mmu_tracker;
61 G1IHOPControl* _ihop_control;
62
63 GCPolicyCounters* _policy_counters;
64
65 double _full_collection_start_sec;
66
67 uint _young_list_target_length;
68 uint _young_list_fixed_length;
69
70 // The max number of regions we can extend the eden by while the GC
71 // locker is active. This should be >= _young_list_target_length;
72 uint _young_list_max_length;
73
74 // SurvRateGroups below must be initialized after the predictor because they
75 // indirectly use it through this object passed to their constructor.
76 SurvRateGroup* _short_lived_surv_rate_group;
77 SurvRateGroup* _survivor_surv_rate_group;
78
79 double _reserve_factor;
80 // This will be set when the heap is expanded
81 // for the first time during initialization.
82 uint _reserve_regions;
83
84 G1YoungGenSizer _young_gen_sizer;
85
86 uint _free_regions_at_end_of_collection;
87
88 size_t _max_rs_lengths;
89
90 size_t _rs_lengths_prediction;
91
92 size_t _pending_cards;
93
94 // The amount of allocated bytes in old gen during the last mutator and the following
95 // young GC phase.
96 size_t _bytes_allocated_in_old_since_last_gc;
97
98 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
99 public:
100 const G1Predictions& predictor() const { return _predictor; }
101 const G1Analytics* analytics() const { return const_cast<const G1Analytics*>(_analytics); }
102
103 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
104
105 void set_region_eden(HeapRegion* hr) {
106 hr->set_eden();
107 hr->install_surv_rate_group(_short_lived_surv_rate_group);
108 }
109
110 void set_region_survivor(HeapRegion* hr) {
111 assert(hr->is_survivor(), "pre-condition");
112 hr->install_surv_rate_group(_survivor_surv_rate_group);
113 }
114
115 void record_max_rs_lengths(size_t rs_lengths) {
116 _max_rs_lengths = rs_lengths;
117 }
118
119
120 double predict_base_elapsed_time_ms(size_t pending_cards) const;
121 double predict_base_elapsed_time_ms(size_t pending_cards,
122 size_t scanned_cards) const;
123 size_t predict_bytes_to_copy(HeapRegion* hr) const;
124 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
125
126 double predict_survivor_regions_evac_time() const;
127
128 bool should_update_surv_rate_group_predictors() {
129 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
130 }
131
132 void cset_regions_freed() {
133 bool update = should_update_surv_rate_group_predictors();
134
135 _short_lived_surv_rate_group->all_surviving_words_recorded(predictor(), update);
136 _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
137 }
138
139 G1MMUTracker* mmu_tracker() {
140 return _mmu_tracker;
141 }
142
143 const G1MMUTracker* mmu_tracker() const {
144 return _mmu_tracker;
145 }
146
147 double max_pause_time_ms() const {
148 return _mmu_tracker->max_gc_time() * 1000.0;
149 }
150
151 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
152
153 double predict_yg_surv_rate(int age) const;
154
155 double accum_yg_surv_rate_pred(int age) const;
156
157 protected:
158 G1CollectionSet* _collection_set;
159 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
160 virtual double other_time_ms(double pause_time_ms) const;
161
162 double young_other_time_ms() const;
163 double non_young_other_time_ms() const;
164 double constant_other_time_ms(double pause_time_ms) const;
165
166 CollectionSetChooser* cset_chooser() const;
167 private:
168
169 // The number of bytes copied during the GC.
170 size_t _bytes_copied_during_gc;
171
172 // Stash a pointer to the g1 heap.
173 G1CollectedHeap* _g1;
174
175 G1GCPhaseTimes* _phase_times;
176
177 // This set of variables tracks the collector efficiency, in order to
178 // determine whether we should initiate a new marking.
179 double _mark_remark_start_sec;
180 double _mark_cleanup_start_sec;
181
182 // Updates the internal young list maximum and target lengths. Returns the
183 // unbounded young list target length.
184 uint update_young_list_max_and_target_length();
185 uint update_young_list_max_and_target_length(size_t rs_lengths);
186
187 // Update the young list target length either by setting it to the
188 // desired fixed value or by calculating it using G1's pause
189 // prediction model. If no rs_lengths parameter is passed, predict
190 // the RS lengths using the prediction model, otherwise use the
191 // given rs_lengths as the prediction.
192 // Returns the unbounded young list target length.
193 uint update_young_list_target_length(size_t rs_lengths);
194
195 // Calculate and return the minimum desired young list target
196 // length. This is the minimum desired young list length according
197 // to the user's inputs.
198 uint calculate_young_list_desired_min_length(uint base_min_length) const;
199
200 // Calculate and return the maximum desired young list target
201 // length. This is the maximum desired young list length according
202 // to the user's inputs.
203 uint calculate_young_list_desired_max_length() const;
204
205 // Calculate and return the maximum young list target length that
206 // can fit into the pause time goal. The parameters are: rs_lengths
207 // represent the prediction of how large the young RSet lengths will
208 // be, base_min_length is the already existing number of regions in
209 // the young list, min_length and max_length are the desired min and
210 // max young list length according to the user's inputs.
211 uint calculate_young_list_target_length(size_t rs_lengths,
212 uint base_min_length,
213 uint desired_min_length,
214 uint desired_max_length) const;
215
216 // Result of the bounded_young_list_target_length() method, containing both the
217 // bounded as well as the unbounded young list target lengths in this order.
218 typedef Pair<uint, uint, StackObj> YoungTargetLengths;
219 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
220
221 void update_rs_lengths_prediction();
222 void update_rs_lengths_prediction(size_t prediction);
223
224 // Check whether a given young length (young_length) fits into the
225 // given target pause time and whether the prediction for the amount
226 // of objects to be copied for the given length will fit into the
227 // given free space (expressed by base_free_regions). It is used by
228 // calculate_young_list_target_length().
229 bool predict_will_fit(uint young_length, double base_time_ms,
230 uint base_free_regions, double target_pause_time_ms) const;
231
232 public:
233 size_t pending_cards() const { return _pending_cards; }
234
235 uint calc_min_old_cset_length() const;
236 uint calc_max_old_cset_length() const;
237
238 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
239
240 private:
241 // Sets up marking if proper conditions are met.
242 void maybe_start_marking();
243
244 // The kind of STW pause.
245 enum PauseKind {
246 FullGC,
247 YoungOnlyGC,
248 MixedGC,
249 LastYoungGC,
250 InitialMarkGC,
251 Cleanup,
252 Remark
253 };
254
255 // Calculate PauseKind from internal state.
256 PauseKind young_gc_pause_kind() const;
257 // Record the given STW pause with the given start and end times (in s).
258 void record_pause(PauseKind kind, double start, double end);
259 // Indicate that we aborted marking before doing any mixed GCs.
260 void abort_time_to_mixed_tracking();
261 public:
262
263 G1DefaultPolicy();
264
265 virtual ~G1DefaultPolicy();
266
267 G1CollectorState* collector_state() const;
268
269 G1GCPhaseTimes* phase_times() const { return _phase_times; }
270
271 void revise_young_list_target_length_if_necessary(size_t rs_lengths);
272
273 void record_new_heap_size(uint new_number_of_regions);
274
275 void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set);
276
277 virtual void note_gc_start();
278
279 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
280
281 bool about_to_start_mixed_phase() const;
282
283 void record_collection_pause_start(double start_time_sec);
284 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
285
286 void record_full_collection_start();
287 void record_full_collection_end();
288
289 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
290
291 void record_concurrent_mark_remark_start();
292 void record_concurrent_mark_remark_end();
293
294 void record_concurrent_mark_cleanup_start();
295 void record_concurrent_mark_cleanup_end();
296 void record_concurrent_mark_cleanup_completed();
297
298 virtual void print_phases();
299
300 void record_bytes_copied_during_gc(size_t bytes) {
301 _bytes_copied_during_gc += bytes;
302 }
303
304 size_t bytes_copied_during_gc() const {
305 return _bytes_copied_during_gc;
306 }
307
308 bool next_gc_should_be_mixed(const char* true_action_str,
309 const char* false_action_str) const;
310
311 virtual void finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor);
312 private:
313 // Set the state to start a concurrent marking cycle and clear
314 // _initiate_conc_mark_if_possible because it has now been
315 // acted on.
316 void initiate_conc_mark();
317
318 public:
319 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
320
321 void decide_on_conc_mark_initiation();
322
323 void finished_recalculating_age_indexes(bool is_survivors) {
324 if (is_survivors) {
325 _survivor_surv_rate_group->finished_recalculating_age_indexes();
326 } else {
327 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
328 }
329 }
330
331 size_t young_list_target_length() const { return _young_list_target_length; }
332
333 bool should_allocate_mutator_region() const;
334
335 bool can_expand_young_list() const;
336
337 uint young_list_max_length() const {
338 return _young_list_max_length;
339 }
340
341 bool adaptive_young_list_length() const;
342
343 virtual bool should_process_references() const {
344 return true;
345 }
346
347 void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
348
349 private:
350 //
351 // Survivor regions policy.
352 //
353
354 // Current tenuring threshold, set to 0 if the collector reaches the
355 // maximum amount of survivors regions.
356 uint _tenuring_threshold;
357
358 // The limit on the number of regions allocated for survivors.
359 uint _max_survivor_regions;
360
361 AgeTable _survivors_age_table;
362
363 public:
364 uint tenuring_threshold() const { return _tenuring_threshold; }
365
366 uint max_survivor_regions() {
367 return _max_survivor_regions;
368 }
369
370 void note_start_adding_survivor_regions() {
371 _survivor_surv_rate_group->start_adding_regions();
372 }
373
374 void note_stop_adding_survivor_regions() {
375 _survivor_surv_rate_group->stop_adding_regions();
376 }
377
378 void record_age_table(AgeTable* age_table) {
379 _survivors_age_table.merge(age_table);
380 }
381
382 void update_max_gc_locker_expansion();
383
384 void update_survivors_policy();
385 };
386
387 #endif // SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP