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 class STWGCTimer;
48
49 class G1DefaultPolicy: public G1Policy {
50 private:
51
52 static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
53 // Update the IHOP control with necessary statistics.
54 void update_ihop_prediction(double mutator_time_s,
55 size_t mutator_alloc_bytes,
56 size_t young_gen_size);
57 void report_ihop_statistics();
58
59 G1Predictions _predictor;
60 G1Analytics* _analytics;
61 G1MMUTracker* _mmu_tracker;
62 G1IHOPControl* _ihop_control;
63
64 GCPolicyCounters* _policy_counters;
65
66 double _full_collection_start_sec;
67
68 jlong _collection_pause_end_millis;
69
70 uint _young_list_target_length;
71 uint _young_list_fixed_length;
72
73 // The max number of regions we can extend the eden by while the GC
74 // locker is active. This should be >= _young_list_target_length;
75 uint _young_list_max_length;
76
77 // SurvRateGroups below must be initialized after the predictor because they
78 // indirectly use it through this object passed to their constructor.
79 SurvRateGroup* _short_lived_surv_rate_group;
80 SurvRateGroup* _survivor_surv_rate_group;
81
82 double _reserve_factor;
83 // This will be set when the heap is expanded
84 // for the first time during initialization.
85 uint _reserve_regions;
86
87 G1YoungGenSizer _young_gen_sizer;
88
89 uint _free_regions_at_end_of_collection;
90
91 size_t _max_rs_lengths;
92
93 size_t _rs_lengths_prediction;
94
95 size_t _pending_cards;
96
97 // The amount of allocated bytes in old gen during the last mutator and the following
98 // young GC phase.
99 size_t _bytes_allocated_in_old_since_last_gc;
100
101 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
102 public:
103 const G1Predictions& predictor() const { return _predictor; }
104 const G1Analytics* analytics() const { return const_cast<const G1Analytics*>(_analytics); }
105
106 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
107
108 void set_region_eden(HeapRegion* hr) {
109 hr->set_eden();
110 hr->install_surv_rate_group(_short_lived_surv_rate_group);
111 }
112
113 void set_region_survivor(HeapRegion* hr) {
114 assert(hr->is_survivor(), "pre-condition");
115 hr->install_surv_rate_group(_survivor_surv_rate_group);
116 }
117
118 void record_max_rs_lengths(size_t rs_lengths) {
119 _max_rs_lengths = rs_lengths;
120 }
121
122
123 double predict_base_elapsed_time_ms(size_t pending_cards) const;
124 double predict_base_elapsed_time_ms(size_t pending_cards,
125 size_t scanned_cards) const;
126 size_t predict_bytes_to_copy(HeapRegion* hr) const;
127 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
128
129 double predict_survivor_regions_evac_time() const;
130
131 bool should_update_surv_rate_group_predictors() {
132 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
133 }
134
135 void cset_regions_freed() {
136 bool update = should_update_surv_rate_group_predictors();
137
138 _short_lived_surv_rate_group->all_surviving_words_recorded(predictor(), update);
139 _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
140 }
141
142 G1MMUTracker* mmu_tracker() {
143 return _mmu_tracker;
144 }
145
146 const G1MMUTracker* mmu_tracker() const {
147 return _mmu_tracker;
148 }
149
150 double max_pause_time_ms() const {
151 return _mmu_tracker->max_gc_time() * 1000.0;
152 }
153
154 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
155
156 double predict_yg_surv_rate(int age) const;
157
158 double accum_yg_surv_rate_pred(int age) const;
159
160 protected:
161 G1CollectionSet* _collection_set;
162 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
163 virtual double other_time_ms(double pause_time_ms) const;
164
165 double young_other_time_ms() const;
166 double non_young_other_time_ms() const;
167 double constant_other_time_ms(double pause_time_ms) const;
168
169 CollectionSetChooser* cset_chooser() const;
170 private:
171
172 // The number of bytes copied during the GC.
173 size_t _bytes_copied_during_gc;
174
175 // Stash a pointer to the g1 heap.
176 G1CollectedHeap* _g1;
177
178 G1GCPhaseTimes* _phase_times;
179
180 // This set of variables tracks the collector efficiency, in order to
181 // determine whether we should initiate a new marking.
182 double _mark_remark_start_sec;
183 double _mark_cleanup_start_sec;
184
185 // Updates the internal young list maximum and target lengths. Returns the
186 // unbounded young list target length.
187 uint update_young_list_max_and_target_length();
188 uint update_young_list_max_and_target_length(size_t rs_lengths);
189
190 // Update the young list target length either by setting it to the
191 // desired fixed value or by calculating it using G1's pause
192 // prediction model. If no rs_lengths parameter is passed, predict
193 // the RS lengths using the prediction model, otherwise use the
194 // given rs_lengths as the prediction.
195 // Returns the unbounded young list target length.
196 uint update_young_list_target_length(size_t rs_lengths);
197
198 // Calculate and return the minimum desired young list target
199 // length. This is the minimum desired young list length according
200 // to the user's inputs.
201 uint calculate_young_list_desired_min_length(uint base_min_length) const;
202
203 // Calculate and return the maximum desired young list target
204 // length. This is the maximum desired young list length according
205 // to the user's inputs.
206 uint calculate_young_list_desired_max_length() const;
207
208 // Calculate and return the maximum young list target length that
209 // can fit into the pause time goal. The parameters are: rs_lengths
210 // represent the prediction of how large the young RSet lengths will
211 // be, base_min_length is the already existing number of regions in
212 // the young list, min_length and max_length are the desired min and
213 // max young list length according to the user's inputs.
214 uint calculate_young_list_target_length(size_t rs_lengths,
215 uint base_min_length,
216 uint desired_min_length,
217 uint desired_max_length) const;
218
219 // Result of the bounded_young_list_target_length() method, containing both the
220 // bounded as well as the unbounded young list target lengths in this order.
221 typedef Pair<uint, uint, StackObj> YoungTargetLengths;
222 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
223
224 void update_rs_lengths_prediction();
225 void update_rs_lengths_prediction(size_t prediction);
226
227 // Check whether a given young length (young_length) fits into the
228 // given target pause time and whether the prediction for the amount
229 // of objects to be copied for the given length will fit into the
230 // given free space (expressed by base_free_regions). It is used by
231 // calculate_young_list_target_length().
232 bool predict_will_fit(uint young_length, double base_time_ms,
233 uint base_free_regions, double target_pause_time_ms) const;
234
235 public:
236 size_t pending_cards() const { return _pending_cards; }
237
238 uint calc_min_old_cset_length() const;
239 uint calc_max_old_cset_length() const;
240
241 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
242
243 jlong collection_pause_end_millis() { return _collection_pause_end_millis; }
244
245 private:
246 // Sets up marking if proper conditions are met.
247 void maybe_start_marking();
248
249 // The kind of STW pause.
250 enum PauseKind {
251 FullGC,
252 YoungOnlyGC,
253 MixedGC,
254 LastYoungGC,
255 InitialMarkGC,
256 Cleanup,
257 Remark
258 };
259
260 // Calculate PauseKind from internal state.
261 PauseKind young_gc_pause_kind() const;
262 // Record the given STW pause with the given start and end times (in s).
263 void record_pause(PauseKind kind, double start, double end);
264 // Indicate that we aborted marking before doing any mixed GCs.
265 void abort_time_to_mixed_tracking();
266 public:
267
268 G1DefaultPolicy(STWGCTimer* gc_timer);
269
270 virtual ~G1DefaultPolicy();
271
272 G1CollectorState* collector_state() const;
273
274 G1GCPhaseTimes* phase_times() const { return _phase_times; }
275
276 void revise_young_list_target_length_if_necessary(size_t rs_lengths);
277
278 void record_new_heap_size(uint new_number_of_regions);
279
280 void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set);
281
282 virtual void note_gc_start();
283
284 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
285
286 bool about_to_start_mixed_phase() const;
287
288 void record_collection_pause_start(double start_time_sec);
289 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
290
291 void record_full_collection_start();
292 void record_full_collection_end();
293
294 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
295
296 void record_concurrent_mark_remark_start();
297 void record_concurrent_mark_remark_end();
298
299 void record_concurrent_mark_cleanup_start();
300 void record_concurrent_mark_cleanup_end();
301 void record_concurrent_mark_cleanup_completed();
302
303 virtual void print_phases();
304
305 void record_bytes_copied_during_gc(size_t bytes) {
306 _bytes_copied_during_gc += bytes;
307 }
308
309 size_t bytes_copied_during_gc() const {
310 return _bytes_copied_during_gc;
311 }
312
313 bool next_gc_should_be_mixed(const char* true_action_str,
314 const char* false_action_str) const;
315
316 virtual void finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor);
317 private:
318 // Set the state to start a concurrent marking cycle and clear
319 // _initiate_conc_mark_if_possible because it has now been
320 // acted on.
321 void initiate_conc_mark();
322
323 public:
324 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
325
326 void decide_on_conc_mark_initiation();
327
328 void finished_recalculating_age_indexes(bool is_survivors) {
329 if (is_survivors) {
330 _survivor_surv_rate_group->finished_recalculating_age_indexes();
331 } else {
332 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
333 }
334 }
335
336 size_t young_list_target_length() const { return _young_list_target_length; }
337
338 bool should_allocate_mutator_region() const;
339
340 bool can_expand_young_list() const;
341
342 uint young_list_max_length() const {
343 return _young_list_max_length;
344 }
345
346 bool adaptive_young_list_length() const;
347
348 virtual bool should_process_references() const {
349 return true;
350 }
351
352 void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
353
354 private:
355 //
356 // Survivor regions policy.
357 //
358
359 // Current tenuring threshold, set to 0 if the collector reaches the
360 // maximum amount of survivors regions.
361 uint _tenuring_threshold;
362
363 // The limit on the number of regions allocated for survivors.
364 uint _max_survivor_regions;
365
366 AgeTable _survivors_age_table;
367
368 protected:
369 size_t desired_survivor_size() const;
370 public:
371 uint tenuring_threshold() const { return _tenuring_threshold; }
372
373 uint max_survivor_regions() {
374 return _max_survivor_regions;
375 }
376
377 void note_start_adding_survivor_regions() {
378 _survivor_surv_rate_group->start_adding_regions();
379 }
380
381 void note_stop_adding_survivor_regions() {
382 _survivor_surv_rate_group->stop_adding_regions();
383 }
384
385 void record_age_table(AgeTable* age_table) {
386 _survivors_age_table.merge(age_table);
387 }
388
389 void print_age_table();
390
391 void update_max_gc_locker_expansion();
392
393 void update_survivors_policy();
394 };
395
396 #endif // SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP