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rev 7125 : 7176220: 'Full GC' events miss date stamp information occasionally
Summary: Move date stamp logic into GCTraceTime
Reviewed-by: brutisso, tschatzl
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--- old/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
+++ new/hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
1 1 /*
2 2 * Copyright (c) 2002, 2014, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "classfile/symbolTable.hpp"
27 27 #include "code/codeCache.hpp"
28 28 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
29 29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
30 30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
31 31 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
32 32 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
33 33 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
34 34 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
35 35 #include "gc_implementation/parallelScavenge/psTasks.hpp"
36 36 #include "gc_implementation/shared/gcHeapSummary.hpp"
37 37 #include "gc_implementation/shared/gcTimer.hpp"
38 38 #include "gc_implementation/shared/gcTrace.hpp"
39 39 #include "gc_implementation/shared/gcTraceTime.hpp"
40 40 #include "gc_implementation/shared/isGCActiveMark.hpp"
41 41 #include "gc_implementation/shared/spaceDecorator.hpp"
42 42 #include "gc_interface/gcCause.hpp"
43 43 #include "memory/collectorPolicy.hpp"
44 44 #include "memory/gcLocker.inline.hpp"
45 45 #include "memory/referencePolicy.hpp"
46 46 #include "memory/referenceProcessor.hpp"
47 47 #include "memory/resourceArea.hpp"
48 48 #include "oops/oop.inline.hpp"
49 49 #include "oops/oop.psgc.inline.hpp"
50 50 #include "runtime/biasedLocking.hpp"
51 51 #include "runtime/fprofiler.hpp"
52 52 #include "runtime/handles.inline.hpp"
53 53 #include "runtime/threadCritical.hpp"
54 54 #include "runtime/vmThread.hpp"
55 55 #include "runtime/vm_operations.hpp"
56 56 #include "services/memoryService.hpp"
57 57 #include "utilities/stack.inline.hpp"
58 58
59 59 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
60 60
61 61 HeapWord* PSScavenge::_to_space_top_before_gc = NULL;
62 62 int PSScavenge::_consecutive_skipped_scavenges = 0;
63 63 ReferenceProcessor* PSScavenge::_ref_processor = NULL;
64 64 CardTableExtension* PSScavenge::_card_table = NULL;
65 65 bool PSScavenge::_survivor_overflow = false;
66 66 uint PSScavenge::_tenuring_threshold = 0;
67 67 HeapWord* PSScavenge::_young_generation_boundary = NULL;
68 68 uintptr_t PSScavenge::_young_generation_boundary_compressed = 0;
69 69 elapsedTimer PSScavenge::_accumulated_time;
70 70 STWGCTimer PSScavenge::_gc_timer;
71 71 ParallelScavengeTracer PSScavenge::_gc_tracer;
72 72 Stack<markOop, mtGC> PSScavenge::_preserved_mark_stack;
73 73 Stack<oop, mtGC> PSScavenge::_preserved_oop_stack;
74 74 CollectorCounters* PSScavenge::_counters = NULL;
75 75
76 76 // Define before use
77 77 class PSIsAliveClosure: public BoolObjectClosure {
78 78 public:
79 79 bool do_object_b(oop p) {
80 80 return (!PSScavenge::is_obj_in_young(p)) || p->is_forwarded();
81 81 }
82 82 };
83 83
84 84 PSIsAliveClosure PSScavenge::_is_alive_closure;
85 85
86 86 class PSKeepAliveClosure: public OopClosure {
87 87 protected:
88 88 MutableSpace* _to_space;
89 89 PSPromotionManager* _promotion_manager;
90 90
91 91 public:
92 92 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
93 93 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
94 94 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
95 95 _to_space = heap->young_gen()->to_space();
96 96
97 97 assert(_promotion_manager != NULL, "Sanity");
98 98 }
99 99
100 100 template <class T> void do_oop_work(T* p) {
101 101 assert (!oopDesc::is_null(*p), "expected non-null ref");
102 102 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(),
103 103 "expected an oop while scanning weak refs");
104 104
105 105 // Weak refs may be visited more than once.
106 106 if (PSScavenge::should_scavenge(p, _to_space)) {
107 107 PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
108 108 }
109 109 }
110 110 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); }
111 111 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); }
112 112 };
113 113
114 114 class PSEvacuateFollowersClosure: public VoidClosure {
115 115 private:
116 116 PSPromotionManager* _promotion_manager;
117 117 public:
118 118 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {}
119 119
120 120 virtual void do_void() {
121 121 assert(_promotion_manager != NULL, "Sanity");
122 122 _promotion_manager->drain_stacks(true);
123 123 guarantee(_promotion_manager->stacks_empty(),
124 124 "stacks should be empty at this point");
125 125 }
126 126 };
127 127
128 128 class PSPromotionFailedClosure : public ObjectClosure {
129 129 virtual void do_object(oop obj) {
130 130 if (obj->is_forwarded()) {
131 131 obj->init_mark();
132 132 }
133 133 }
134 134 };
135 135
136 136 class PSRefProcTaskProxy: public GCTask {
137 137 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
138 138 ProcessTask & _rp_task;
139 139 uint _work_id;
140 140 public:
141 141 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id)
142 142 : _rp_task(rp_task),
143 143 _work_id(work_id)
144 144 { }
145 145
146 146 private:
147 147 virtual char* name() { return (char *)"Process referents by policy in parallel"; }
148 148 virtual void do_it(GCTaskManager* manager, uint which);
149 149 };
150 150
151 151 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which)
152 152 {
153 153 PSPromotionManager* promotion_manager =
154 154 PSPromotionManager::gc_thread_promotion_manager(which);
155 155 assert(promotion_manager != NULL, "sanity check");
156 156 PSKeepAliveClosure keep_alive(promotion_manager);
157 157 PSEvacuateFollowersClosure evac_followers(promotion_manager);
158 158 PSIsAliveClosure is_alive;
159 159 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers);
160 160 }
161 161
162 162 class PSRefEnqueueTaskProxy: public GCTask {
163 163 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
164 164 EnqueueTask& _enq_task;
165 165 uint _work_id;
166 166
167 167 public:
168 168 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id)
169 169 : _enq_task(enq_task),
170 170 _work_id(work_id)
171 171 { }
172 172
173 173 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; }
174 174 virtual void do_it(GCTaskManager* manager, uint which)
175 175 {
176 176 _enq_task.work(_work_id);
177 177 }
178 178 };
179 179
180 180 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
181 181 virtual void execute(ProcessTask& task);
182 182 virtual void execute(EnqueueTask& task);
183 183 };
184 184
185 185 void PSRefProcTaskExecutor::execute(ProcessTask& task)
186 186 {
187 187 GCTaskQueue* q = GCTaskQueue::create();
188 188 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
189 189 for(uint i=0; i < manager->active_workers(); i++) {
190 190 q->enqueue(new PSRefProcTaskProxy(task, i));
191 191 }
192 192 ParallelTaskTerminator terminator(manager->active_workers(),
193 193 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
194 194 if (task.marks_oops_alive() && manager->active_workers() > 1) {
195 195 for (uint j = 0; j < manager->active_workers(); j++) {
196 196 q->enqueue(new StealTask(&terminator));
197 197 }
198 198 }
199 199 manager->execute_and_wait(q);
200 200 }
201 201
202 202
203 203 void PSRefProcTaskExecutor::execute(EnqueueTask& task)
204 204 {
205 205 GCTaskQueue* q = GCTaskQueue::create();
206 206 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
207 207 for(uint i=0; i < manager->active_workers(); i++) {
208 208 q->enqueue(new PSRefEnqueueTaskProxy(task, i));
209 209 }
210 210 manager->execute_and_wait(q);
211 211 }
212 212
213 213 // This method contains all heap specific policy for invoking scavenge.
214 214 // PSScavenge::invoke_no_policy() will do nothing but attempt to
215 215 // scavenge. It will not clean up after failed promotions, bail out if
216 216 // we've exceeded policy time limits, or any other special behavior.
217 217 // All such policy should be placed here.
218 218 //
219 219 // Note that this method should only be called from the vm_thread while
220 220 // at a safepoint!
221 221 bool PSScavenge::invoke() {
222 222 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
223 223 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
224 224 assert(!Universe::heap()->is_gc_active(), "not reentrant");
225 225
226 226 ParallelScavengeHeap* const heap = (ParallelScavengeHeap*)Universe::heap();
227 227 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
228 228
229 229 PSAdaptiveSizePolicy* policy = heap->size_policy();
230 230 IsGCActiveMark mark;
231 231
232 232 const bool scavenge_done = PSScavenge::invoke_no_policy();
233 233 const bool need_full_gc = !scavenge_done ||
234 234 policy->should_full_GC(heap->old_gen()->free_in_bytes());
235 235 bool full_gc_done = false;
236 236
237 237 if (UsePerfData) {
238 238 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
239 239 const int ffs_val = need_full_gc ? full_follows_scavenge : not_skipped;
240 240 counters->update_full_follows_scavenge(ffs_val);
241 241 }
242 242
243 243 if (need_full_gc) {
244 244 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
245 245 CollectorPolicy* cp = heap->collector_policy();
246 246 const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
247 247
248 248 if (UseParallelOldGC) {
249 249 full_gc_done = PSParallelCompact::invoke_no_policy(clear_all_softrefs);
250 250 } else {
251 251 full_gc_done = PSMarkSweep::invoke_no_policy(clear_all_softrefs);
252 252 }
253 253 }
254 254
255 255 return full_gc_done;
256 256 }
257 257
258 258 // This method contains no policy. You should probably
259 259 // be calling invoke() instead.
260 260 bool PSScavenge::invoke_no_policy() {
261 261 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
262 262 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
263 263
264 264 assert(_preserved_mark_stack.is_empty(), "should be empty");
265 265 assert(_preserved_oop_stack.is_empty(), "should be empty");
266 266
267 267 _gc_timer.register_gc_start();
268 268
269 269 TimeStamp scavenge_entry;
270 270 TimeStamp scavenge_midpoint;
271 271 TimeStamp scavenge_exit;
272 272
273 273 scavenge_entry.update();
274 274
275 275 if (GC_locker::check_active_before_gc()) {
276 276 return false;
277 277 }
278 278
279 279 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
280 280 GCCause::Cause gc_cause = heap->gc_cause();
281 281 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
282 282
283 283 // Check for potential problems.
284 284 if (!should_attempt_scavenge()) {
285 285 return false;
286 286 }
287 287
288 288 _gc_tracer.report_gc_start(heap->gc_cause(), _gc_timer.gc_start());
289 289
290 290 bool promotion_failure_occurred = false;
291 291
292 292 PSYoungGen* young_gen = heap->young_gen();
293 293 PSOldGen* old_gen = heap->old_gen();
294 294 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
295 295
296 296 heap->increment_total_collections();
297 297
298 298 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
299 299
300 300 if ((gc_cause != GCCause::_java_lang_system_gc) ||
301 301 UseAdaptiveSizePolicyWithSystemGC) {
302 302 // Gather the feedback data for eden occupancy.
303 303 young_gen->eden_space()->accumulate_statistics();
304 304 }
305 305
306 306 if (ZapUnusedHeapArea) {
307 307 // Save information needed to minimize mangling
308 308 heap->record_gen_tops_before_GC();
309 309 }
310 310
311 311 heap->print_heap_before_gc();
312 312 heap->trace_heap_before_gc(&_gc_tracer);
313 313
314 314 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity");
315 315 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity");
316 316
317 317 size_t prev_used = heap->used();
318 318
319 319 // Fill in TLABs
320 320 heap->accumulate_statistics_all_tlabs();
321 321 heap->ensure_parsability(true); // retire TLABs
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322 322
323 323 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
324 324 HandleMark hm; // Discard invalid handles created during verification
325 325 Universe::verify(" VerifyBeforeGC:");
326 326 }
327 327
328 328 {
329 329 ResourceMark rm;
330 330 HandleMark hm;
331 331
332 - gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
333 332 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
334 333 GCTraceTime t1(GCCauseString("GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer.gc_id());
335 334 TraceCollectorStats tcs(counters());
336 335 TraceMemoryManagerStats tms(false /* not full GC */,gc_cause);
337 336
338 337 if (TraceGen0Time) accumulated_time()->start();
339 338
340 339 // Let the size policy know we're starting
341 340 size_policy->minor_collection_begin();
342 341
343 342 // Verify the object start arrays.
344 343 if (VerifyObjectStartArray &&
345 344 VerifyBeforeGC) {
346 345 old_gen->verify_object_start_array();
347 346 }
348 347
349 348 // Verify no unmarked old->young roots
350 349 if (VerifyRememberedSets) {
351 350 CardTableExtension::verify_all_young_refs_imprecise();
352 351 }
353 352
354 353 if (!ScavengeWithObjectsInToSpace) {
355 354 assert(young_gen->to_space()->is_empty(),
356 355 "Attempt to scavenge with live objects in to_space");
357 356 young_gen->to_space()->clear(SpaceDecorator::Mangle);
358 357 } else if (ZapUnusedHeapArea) {
359 358 young_gen->to_space()->mangle_unused_area();
360 359 }
361 360 save_to_space_top_before_gc();
362 361
363 362 COMPILER2_PRESENT(DerivedPointerTable::clear());
364 363
365 364 reference_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
366 365 reference_processor()->setup_policy(false);
367 366
368 367 // We track how much was promoted to the next generation for
369 368 // the AdaptiveSizePolicy.
370 369 size_t old_gen_used_before = old_gen->used_in_bytes();
371 370
372 371 // For PrintGCDetails
373 372 size_t young_gen_used_before = young_gen->used_in_bytes();
374 373
375 374 // Reset our survivor overflow.
376 375 set_survivor_overflow(false);
377 376
378 377 // We need to save the old top values before
379 378 // creating the promotion_manager. We pass the top
380 379 // values to the card_table, to prevent it from
381 380 // straying into the promotion labs.
382 381 HeapWord* old_top = old_gen->object_space()->top();
383 382
384 383 // Release all previously held resources
385 384 gc_task_manager()->release_all_resources();
386 385
387 386 // Set the number of GC threads to be used in this collection
388 387 gc_task_manager()->set_active_gang();
389 388 gc_task_manager()->task_idle_workers();
390 389 // Get the active number of workers here and use that value
391 390 // throughout the methods.
392 391 uint active_workers = gc_task_manager()->active_workers();
393 392 heap->set_par_threads(active_workers);
394 393
395 394 PSPromotionManager::pre_scavenge();
396 395
397 396 // We'll use the promotion manager again later.
398 397 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager();
399 398 {
400 399 GCTraceTime tm("Scavenge", false, false, &_gc_timer, _gc_tracer.gc_id());
401 400 ParallelScavengeHeap::ParStrongRootsScope psrs;
402 401
403 402 GCTaskQueue* q = GCTaskQueue::create();
404 403
405 404 if (!old_gen->object_space()->is_empty()) {
406 405 // There are only old-to-young pointers if there are objects
407 406 // in the old gen.
408 407 uint stripe_total = active_workers;
409 408 for(uint i=0; i < stripe_total; i++) {
410 409 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total));
411 410 }
412 411 }
413 412
414 413 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe));
415 414 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles));
416 415 // We scan the thread roots in parallel
417 416 Threads::create_thread_roots_tasks(q);
418 417 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer));
419 418 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler));
420 419 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management));
421 420 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary));
422 421 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::class_loader_data));
423 422 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti));
424 423 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache));
425 424
426 425 ParallelTaskTerminator terminator(
427 426 active_workers,
428 427 (TaskQueueSetSuper*) promotion_manager->stack_array_depth());
429 428 if (active_workers > 1) {
430 429 for (uint j = 0; j < active_workers; j++) {
431 430 q->enqueue(new StealTask(&terminator));
432 431 }
433 432 }
434 433
435 434 gc_task_manager()->execute_and_wait(q);
436 435 }
437 436
438 437 scavenge_midpoint.update();
439 438
440 439 // Process reference objects discovered during scavenge
441 440 {
442 441 GCTraceTime tm("References", false, false, &_gc_timer, _gc_tracer.gc_id());
443 442
444 443 reference_processor()->setup_policy(false); // not always_clear
445 444 reference_processor()->set_active_mt_degree(active_workers);
446 445 PSKeepAliveClosure keep_alive(promotion_manager);
447 446 PSEvacuateFollowersClosure evac_followers(promotion_manager);
448 447 ReferenceProcessorStats stats;
449 448 if (reference_processor()->processing_is_mt()) {
450 449 PSRefProcTaskExecutor task_executor;
451 450 stats = reference_processor()->process_discovered_references(
452 451 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor,
453 452 &_gc_timer, _gc_tracer.gc_id());
454 453 } else {
455 454 stats = reference_processor()->process_discovered_references(
456 455 &_is_alive_closure, &keep_alive, &evac_followers, NULL, &_gc_timer, _gc_tracer.gc_id());
457 456 }
458 457
459 458 _gc_tracer.report_gc_reference_stats(stats);
460 459
461 460 // Enqueue reference objects discovered during scavenge.
462 461 if (reference_processor()->processing_is_mt()) {
463 462 PSRefProcTaskExecutor task_executor;
464 463 reference_processor()->enqueue_discovered_references(&task_executor);
465 464 } else {
466 465 reference_processor()->enqueue_discovered_references(NULL);
467 466 }
468 467 }
469 468
470 469 {
471 470 GCTraceTime tm("StringTable", false, false, &_gc_timer, _gc_tracer.gc_id());
472 471 // Unlink any dead interned Strings and process the remaining live ones.
473 472 PSScavengeRootsClosure root_closure(promotion_manager);
474 473 StringTable::unlink_or_oops_do(&_is_alive_closure, &root_closure);
475 474 }
476 475
477 476 // Finally, flush the promotion_manager's labs, and deallocate its stacks.
478 477 promotion_failure_occurred = PSPromotionManager::post_scavenge(_gc_tracer);
479 478 if (promotion_failure_occurred) {
480 479 clean_up_failed_promotion();
481 480 if (PrintGC) {
482 481 gclog_or_tty->print("--");
483 482 }
484 483 }
485 484
486 485 // Let the size policy know we're done. Note that we count promotion
487 486 // failure cleanup time as part of the collection (otherwise, we're
488 487 // implicitly saying it's mutator time).
489 488 size_policy->minor_collection_end(gc_cause);
490 489
491 490 if (!promotion_failure_occurred) {
492 491 // Swap the survivor spaces.
493 492 young_gen->eden_space()->clear(SpaceDecorator::Mangle);
494 493 young_gen->from_space()->clear(SpaceDecorator::Mangle);
495 494 young_gen->swap_spaces();
496 495
497 496 size_t survived = young_gen->from_space()->used_in_bytes();
498 497 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before;
499 498 size_policy->update_averages(_survivor_overflow, survived, promoted);
500 499
501 500 // A successful scavenge should restart the GC time limit count which is
502 501 // for full GC's.
503 502 size_policy->reset_gc_overhead_limit_count();
504 503 if (UseAdaptiveSizePolicy) {
505 504 // Calculate the new survivor size and tenuring threshold
506 505
507 506 if (PrintAdaptiveSizePolicy) {
508 507 gclog_or_tty->print("AdaptiveSizeStart: ");
509 508 gclog_or_tty->stamp();
510 509 gclog_or_tty->print_cr(" collection: %d ",
511 510 heap->total_collections());
512 511
513 512 if (Verbose) {
514 513 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d",
515 514 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
516 515 }
517 516 }
518 517
519 518
520 519 if (UsePerfData) {
521 520 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
522 521 counters->update_old_eden_size(
523 522 size_policy->calculated_eden_size_in_bytes());
524 523 counters->update_old_promo_size(
525 524 size_policy->calculated_promo_size_in_bytes());
526 525 counters->update_old_capacity(old_gen->capacity_in_bytes());
527 526 counters->update_young_capacity(young_gen->capacity_in_bytes());
528 527 counters->update_survived(survived);
529 528 counters->update_promoted(promoted);
530 529 counters->update_survivor_overflowed(_survivor_overflow);
531 530 }
532 531
533 532 size_t max_young_size = young_gen->max_size();
534 533
535 534 // Deciding a free ratio in the young generation is tricky, so if
536 535 // MinHeapFreeRatio or MaxHeapFreeRatio are in use (implicating
537 536 // that the old generation size may have been limited because of them) we
538 537 // should then limit our young generation size using NewRatio to have it
539 538 // follow the old generation size.
540 539 if (MinHeapFreeRatio != 0 || MaxHeapFreeRatio != 100) {
541 540 max_young_size = MIN2(old_gen->capacity_in_bytes() / NewRatio, young_gen->max_size());
542 541 }
543 542
544 543 size_t survivor_limit =
545 544 size_policy->max_survivor_size(max_young_size);
546 545 _tenuring_threshold =
547 546 size_policy->compute_survivor_space_size_and_threshold(
548 547 _survivor_overflow,
549 548 _tenuring_threshold,
550 549 survivor_limit);
551 550
552 551 if (PrintTenuringDistribution) {
553 552 gclog_or_tty->cr();
554 553 gclog_or_tty->print_cr("Desired survivor size " SIZE_FORMAT " bytes, new threshold %u (max %u)",
555 554 size_policy->calculated_survivor_size_in_bytes(),
556 555 _tenuring_threshold, MaxTenuringThreshold);
557 556 }
558 557
559 558 if (UsePerfData) {
560 559 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
561 560 counters->update_tenuring_threshold(_tenuring_threshold);
562 561 counters->update_survivor_size_counters();
563 562 }
564 563
565 564 // Do call at minor collections?
566 565 // Don't check if the size_policy is ready at this
567 566 // level. Let the size_policy check that internally.
568 567 if (UseAdaptiveGenerationSizePolicyAtMinorCollection &&
569 568 ((gc_cause != GCCause::_java_lang_system_gc) ||
570 569 UseAdaptiveSizePolicyWithSystemGC)) {
571 570
572 571 // Calculate optimial free space amounts
573 572 assert(young_gen->max_size() >
574 573 young_gen->from_space()->capacity_in_bytes() +
575 574 young_gen->to_space()->capacity_in_bytes(),
576 575 "Sizes of space in young gen are out-of-bounds");
577 576
578 577 size_t young_live = young_gen->used_in_bytes();
579 578 size_t eden_live = young_gen->eden_space()->used_in_bytes();
580 579 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
581 580 size_t max_old_gen_size = old_gen->max_gen_size();
582 581 size_t max_eden_size = max_young_size -
583 582 young_gen->from_space()->capacity_in_bytes() -
584 583 young_gen->to_space()->capacity_in_bytes();
585 584
586 585 // Used for diagnostics
587 586 size_policy->clear_generation_free_space_flags();
588 587
589 588 size_policy->compute_eden_space_size(young_live,
590 589 eden_live,
591 590 cur_eden,
592 591 max_eden_size,
593 592 false /* not full gc*/);
594 593
595 594 size_policy->check_gc_overhead_limit(young_live,
596 595 eden_live,
597 596 max_old_gen_size,
598 597 max_eden_size,
599 598 false /* not full gc*/,
600 599 gc_cause,
601 600 heap->collector_policy());
602 601
603 602 size_policy->decay_supplemental_growth(false /* not full gc*/);
604 603 }
605 604 // Resize the young generation at every collection
606 605 // even if new sizes have not been calculated. This is
607 606 // to allow resizes that may have been inhibited by the
608 607 // relative location of the "to" and "from" spaces.
609 608
610 609 // Resizing the old gen at minor collects can cause increases
611 610 // that don't feed back to the generation sizing policy until
612 611 // a major collection. Don't resize the old gen here.
613 612
614 613 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
615 614 size_policy->calculated_survivor_size_in_bytes());
616 615
617 616 if (PrintAdaptiveSizePolicy) {
618 617 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
619 618 heap->total_collections());
620 619 }
621 620 }
622 621
623 622 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can
624 623 // cause the change of the heap layout. Make sure eden is reshaped if that's the case.
625 624 // Also update() will case adaptive NUMA chunk resizing.
626 625 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now");
627 626 young_gen->eden_space()->update();
628 627
629 628 heap->gc_policy_counters()->update_counters();
630 629
631 630 heap->resize_all_tlabs();
632 631
633 632 assert(young_gen->to_space()->is_empty(), "to space should be empty now");
634 633 }
635 634
636 635 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
637 636
638 637 NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
639 638
640 639 {
641 640 GCTraceTime tm("Prune Scavenge Root Methods", false, false, &_gc_timer, _gc_tracer.gc_id());
642 641
643 642 CodeCache::prune_scavenge_root_nmethods();
644 643 }
645 644
646 645 // Re-verify object start arrays
647 646 if (VerifyObjectStartArray &&
648 647 VerifyAfterGC) {
649 648 old_gen->verify_object_start_array();
650 649 }
651 650
652 651 // Verify all old -> young cards are now precise
653 652 if (VerifyRememberedSets) {
654 653 // Precise verification will give false positives. Until this is fixed,
655 654 // use imprecise verification.
656 655 // CardTableExtension::verify_all_young_refs_precise();
657 656 CardTableExtension::verify_all_young_refs_imprecise();
658 657 }
659 658
660 659 if (TraceGen0Time) accumulated_time()->stop();
661 660
662 661 if (PrintGC) {
663 662 if (PrintGCDetails) {
664 663 // Don't print a GC timestamp here. This is after the GC so
665 664 // would be confusing.
666 665 young_gen->print_used_change(young_gen_used_before);
667 666 }
668 667 heap->print_heap_change(prev_used);
669 668 }
670 669
671 670 // Track memory usage and detect low memory
672 671 MemoryService::track_memory_usage();
673 672 heap->update_counters();
674 673
675 674 gc_task_manager()->release_idle_workers();
676 675 }
677 676
678 677 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
679 678 HandleMark hm; // Discard invalid handles created during verification
680 679 Universe::verify(" VerifyAfterGC:");
681 680 }
682 681
683 682 heap->print_heap_after_gc();
684 683 heap->trace_heap_after_gc(&_gc_tracer);
685 684 _gc_tracer.report_tenuring_threshold(tenuring_threshold());
686 685
687 686 if (ZapUnusedHeapArea) {
688 687 young_gen->eden_space()->check_mangled_unused_area_complete();
689 688 young_gen->from_space()->check_mangled_unused_area_complete();
690 689 young_gen->to_space()->check_mangled_unused_area_complete();
691 690 }
692 691
693 692 scavenge_exit.update();
694 693
695 694 if (PrintGCTaskTimeStamps) {
696 695 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT,
697 696 scavenge_entry.ticks(), scavenge_midpoint.ticks(),
698 697 scavenge_exit.ticks());
699 698 gc_task_manager()->print_task_time_stamps();
700 699 }
701 700
702 701 #ifdef TRACESPINNING
703 702 ParallelTaskTerminator::print_termination_counts();
704 703 #endif
705 704
706 705
707 706 _gc_timer.register_gc_end();
708 707
709 708 _gc_tracer.report_gc_end(_gc_timer.gc_end(), _gc_timer.time_partitions());
710 709
711 710 return !promotion_failure_occurred;
712 711 }
713 712
714 713 // This method iterates over all objects in the young generation,
715 714 // unforwarding markOops. It then restores any preserved mark oops,
716 715 // and clears the _preserved_mark_stack.
717 716 void PSScavenge::clean_up_failed_promotion() {
718 717 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
719 718 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
720 719
721 720 PSYoungGen* young_gen = heap->young_gen();
722 721
723 722 {
724 723 ResourceMark rm;
725 724
726 725 // Unforward all pointers in the young gen.
727 726 PSPromotionFailedClosure unforward_closure;
728 727 young_gen->object_iterate(&unforward_closure);
729 728
730 729 if (PrintGC && Verbose) {
731 730 gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size());
732 731 }
733 732
734 733 // Restore any saved marks.
735 734 while (!_preserved_oop_stack.is_empty()) {
736 735 oop obj = _preserved_oop_stack.pop();
737 736 markOop mark = _preserved_mark_stack.pop();
738 737 obj->set_mark(mark);
739 738 }
740 739
741 740 // Clear the preserved mark and oop stack caches.
742 741 _preserved_mark_stack.clear(true);
743 742 _preserved_oop_stack.clear(true);
744 743 }
745 744
746 745 // Reset the PromotionFailureALot counters.
747 746 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
748 747 }
749 748
750 749 // This method is called whenever an attempt to promote an object
751 750 // fails. Some markOops will need preservation, some will not. Note
752 751 // that the entire eden is traversed after a failed promotion, with
753 752 // all forwarded headers replaced by the default markOop. This means
754 753 // it is not necessary to preserve most markOops.
755 754 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) {
756 755 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) {
757 756 // Should use per-worker private stacks here rather than
758 757 // locking a common pair of stacks.
759 758 ThreadCritical tc;
760 759 _preserved_oop_stack.push(obj);
761 760 _preserved_mark_stack.push(obj_mark);
762 761 }
763 762 }
764 763
765 764 bool PSScavenge::should_attempt_scavenge() {
766 765 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
767 766 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
768 767 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
769 768
770 769 if (UsePerfData) {
771 770 counters->update_scavenge_skipped(not_skipped);
772 771 }
773 772
774 773 PSYoungGen* young_gen = heap->young_gen();
775 774 PSOldGen* old_gen = heap->old_gen();
776 775
777 776 if (!ScavengeWithObjectsInToSpace) {
778 777 // Do not attempt to promote unless to_space is empty
779 778 if (!young_gen->to_space()->is_empty()) {
780 779 _consecutive_skipped_scavenges++;
781 780 if (UsePerfData) {
782 781 counters->update_scavenge_skipped(to_space_not_empty);
783 782 }
784 783 return false;
785 784 }
786 785 }
787 786
788 787 // Test to see if the scavenge will likely fail.
789 788 PSAdaptiveSizePolicy* policy = heap->size_policy();
790 789
791 790 // A similar test is done in the policy's should_full_GC(). If this is
792 791 // changed, decide if that test should also be changed.
793 792 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
794 793 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
795 794 bool result = promotion_estimate < old_gen->free_in_bytes();
796 795
797 796 if (PrintGCDetails && Verbose) {
798 797 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: ");
799 798 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
800 799 " padded_average_promoted " SIZE_FORMAT
801 800 " free in old gen " SIZE_FORMAT,
802 801 (size_t) policy->average_promoted_in_bytes(),
803 802 (size_t) policy->padded_average_promoted_in_bytes(),
804 803 old_gen->free_in_bytes());
805 804 if (young_gen->used_in_bytes() <
806 805 (size_t) policy->padded_average_promoted_in_bytes()) {
807 806 gclog_or_tty->print_cr(" padded_promoted_average is greater"
808 807 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
809 808 }
810 809 }
811 810
812 811 if (result) {
813 812 _consecutive_skipped_scavenges = 0;
814 813 } else {
815 814 _consecutive_skipped_scavenges++;
816 815 if (UsePerfData) {
817 816 counters->update_scavenge_skipped(promoted_too_large);
818 817 }
819 818 }
820 819 return result;
821 820 }
822 821
823 822 // Used to add tasks
824 823 GCTaskManager* const PSScavenge::gc_task_manager() {
825 824 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
826 825 "shouldn't return NULL");
827 826 return ParallelScavengeHeap::gc_task_manager();
828 827 }
829 828
830 829 void PSScavenge::initialize() {
831 830 // Arguments must have been parsed
832 831
833 832 if (AlwaysTenure) {
834 833 _tenuring_threshold = 0;
835 834 } else if (NeverTenure) {
836 835 _tenuring_threshold = markOopDesc::max_age + 1;
837 836 } else {
838 837 // We want to smooth out our startup times for the AdaptiveSizePolicy
839 838 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
840 839 MaxTenuringThreshold;
841 840 }
842 841
843 842 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
844 843 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
845 844
846 845 PSYoungGen* young_gen = heap->young_gen();
847 846 PSOldGen* old_gen = heap->old_gen();
848 847
849 848 // Set boundary between young_gen and old_gen
850 849 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
851 850 "old above young");
852 851 set_young_generation_boundary(young_gen->eden_space()->bottom());
853 852
854 853 // Initialize ref handling object for scavenging.
855 854 MemRegion mr = young_gen->reserved();
856 855
857 856 _ref_processor =
858 857 new ReferenceProcessor(mr, // span
859 858 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
860 859 (int) ParallelGCThreads, // mt processing degree
861 860 true, // mt discovery
862 861 (int) ParallelGCThreads, // mt discovery degree
863 862 true, // atomic_discovery
864 863 NULL); // header provides liveness info
865 864
866 865 // Cache the cardtable
867 866 BarrierSet* bs = Universe::heap()->barrier_set();
868 867 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
869 868 _card_table = (CardTableExtension*)bs;
870 869
871 870 _counters = new CollectorCounters("PSScavenge", 0);
872 871 }
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