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