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--- old/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
+++ new/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
1 1 /*
2 2 * Copyright (c) 2002, 2012, 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,
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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 +#include "code/codeCache.hpp"
27 28 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
28 29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
29 30 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
30 31 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
31 32 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
32 33 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
33 34 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
34 35 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
35 36 #include "gc_implementation/parallelScavenge/psTasks.hpp"
36 37 #include "gc_implementation/shared/isGCActiveMark.hpp"
37 38 #include "gc_implementation/shared/spaceDecorator.hpp"
38 39 #include "gc_interface/gcCause.hpp"
39 40 #include "memory/collectorPolicy.hpp"
40 41 #include "memory/gcLocker.inline.hpp"
41 42 #include "memory/referencePolicy.hpp"
42 43 #include "memory/referenceProcessor.hpp"
43 44 #include "memory/resourceArea.hpp"
44 45 #include "oops/oop.inline.hpp"
45 46 #include "oops/oop.psgc.inline.hpp"
46 47 #include "runtime/biasedLocking.hpp"
47 48 #include "runtime/fprofiler.hpp"
48 49 #include "runtime/handles.inline.hpp"
49 50 #include "runtime/threadCritical.hpp"
50 51 #include "runtime/vmThread.hpp"
51 52 #include "runtime/vm_operations.hpp"
52 53 #include "services/memoryService.hpp"
53 54 #include "utilities/stack.inline.hpp"
54 55
55 56
56 57 HeapWord* PSScavenge::_to_space_top_before_gc = NULL;
57 58 int PSScavenge::_consecutive_skipped_scavenges = 0;
58 59 ReferenceProcessor* PSScavenge::_ref_processor = NULL;
59 60 CardTableExtension* PSScavenge::_card_table = NULL;
60 61 bool PSScavenge::_survivor_overflow = false;
61 62 int PSScavenge::_tenuring_threshold = 0;
62 63 HeapWord* PSScavenge::_young_generation_boundary = NULL;
63 64 elapsedTimer PSScavenge::_accumulated_time;
64 65 Stack<markOop> PSScavenge::_preserved_mark_stack;
65 66 Stack<oop> PSScavenge::_preserved_oop_stack;
66 67 CollectorCounters* PSScavenge::_counters = NULL;
67 68 bool PSScavenge::_promotion_failed = false;
68 69
69 70 // Define before use
70 71 class PSIsAliveClosure: public BoolObjectClosure {
71 72 public:
72 73 void do_object(oop p) {
73 74 assert(false, "Do not call.");
74 75 }
75 76 bool do_object_b(oop p) {
76 77 return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded();
77 78 }
78 79 };
79 80
80 81 PSIsAliveClosure PSScavenge::_is_alive_closure;
81 82
82 83 class PSKeepAliveClosure: public OopClosure {
83 84 protected:
84 85 MutableSpace* _to_space;
85 86 PSPromotionManager* _promotion_manager;
86 87
87 88 public:
88 89 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
89 90 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
90 91 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
91 92 _to_space = heap->young_gen()->to_space();
92 93
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93 94 assert(_promotion_manager != NULL, "Sanity");
94 95 }
95 96
96 97 template <class T> void do_oop_work(T* p) {
97 98 assert (!oopDesc::is_null(*p), "expected non-null ref");
98 99 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(),
99 100 "expected an oop while scanning weak refs");
100 101
101 102 // Weak refs may be visited more than once.
102 103 if (PSScavenge::should_scavenge(p, _to_space)) {
103 - PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
104 + PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
104 105 }
105 106 }
106 107 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); }
107 108 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); }
108 109 };
109 110
110 111 class PSEvacuateFollowersClosure: public VoidClosure {
111 112 private:
112 113 PSPromotionManager* _promotion_manager;
113 114 public:
114 115 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {}
115 116
116 117 virtual void do_void() {
117 118 assert(_promotion_manager != NULL, "Sanity");
118 119 _promotion_manager->drain_stacks(true);
119 120 guarantee(_promotion_manager->stacks_empty(),
120 121 "stacks should be empty at this point");
121 122 }
122 123 };
123 124
124 125 class PSPromotionFailedClosure : public ObjectClosure {
125 126 virtual void do_object(oop obj) {
126 127 if (obj->is_forwarded()) {
127 128 obj->init_mark();
128 129 }
129 130 }
130 131 };
131 132
132 133 class PSRefProcTaskProxy: public GCTask {
133 134 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
134 135 ProcessTask & _rp_task;
135 136 uint _work_id;
136 137 public:
137 138 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id)
138 139 : _rp_task(rp_task),
139 140 _work_id(work_id)
140 141 { }
141 142
142 143 private:
143 144 virtual char* name() { return (char *)"Process referents by policy in parallel"; }
144 145 virtual void do_it(GCTaskManager* manager, uint which);
145 146 };
146 147
147 148 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which)
148 149 {
149 150 PSPromotionManager* promotion_manager =
150 151 PSPromotionManager::gc_thread_promotion_manager(which);
151 152 assert(promotion_manager != NULL, "sanity check");
152 153 PSKeepAliveClosure keep_alive(promotion_manager);
153 154 PSEvacuateFollowersClosure evac_followers(promotion_manager);
154 155 PSIsAliveClosure is_alive;
155 156 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers);
156 157 }
157 158
158 159 class PSRefEnqueueTaskProxy: public GCTask {
159 160 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
160 161 EnqueueTask& _enq_task;
161 162 uint _work_id;
162 163
163 164 public:
164 165 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id)
165 166 : _enq_task(enq_task),
166 167 _work_id(work_id)
167 168 { }
168 169
169 170 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; }
170 171 virtual void do_it(GCTaskManager* manager, uint which)
171 172 {
172 173 _enq_task.work(_work_id);
173 174 }
174 175 };
175 176
176 177 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
177 178 virtual void execute(ProcessTask& task);
178 179 virtual void execute(EnqueueTask& task);
179 180 };
180 181
181 182 void PSRefProcTaskExecutor::execute(ProcessTask& task)
182 183 {
183 184 GCTaskQueue* q = GCTaskQueue::create();
184 185 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
185 186 for(uint i=0; i < manager->active_workers(); i++) {
186 187 q->enqueue(new PSRefProcTaskProxy(task, i));
187 188 }
188 189 ParallelTaskTerminator terminator(manager->active_workers(),
189 190 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
190 191 if (task.marks_oops_alive() && manager->active_workers() > 1) {
191 192 for (uint j = 0; j < manager->active_workers(); j++) {
192 193 q->enqueue(new StealTask(&terminator));
193 194 }
194 195 }
195 196 manager->execute_and_wait(q);
196 197 }
197 198
198 199
199 200 void PSRefProcTaskExecutor::execute(EnqueueTask& task)
200 201 {
201 202 GCTaskQueue* q = GCTaskQueue::create();
202 203 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
203 204 for(uint i=0; i < manager->active_workers(); i++) {
204 205 q->enqueue(new PSRefEnqueueTaskProxy(task, i));
205 206 }
206 207 manager->execute_and_wait(q);
207 208 }
208 209
209 210 // This method contains all heap specific policy for invoking scavenge.
210 211 // PSScavenge::invoke_no_policy() will do nothing but attempt to
211 212 // scavenge. It will not clean up after failed promotions, bail out if
212 213 // we've exceeded policy time limits, or any other special behavior.
213 214 // All such policy should be placed here.
214 215 //
215 216 // Note that this method should only be called from the vm_thread while
216 217 // at a safepoint!
217 218 void PSScavenge::invoke() {
218 219 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
219 220 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
220 221 assert(!Universe::heap()->is_gc_active(), "not reentrant");
221 222
222 223 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
223 224 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
224 225
225 226 PSAdaptiveSizePolicy* policy = heap->size_policy();
226 227 IsGCActiveMark mark;
227 228
228 229 bool scavenge_was_done = PSScavenge::invoke_no_policy();
229 230
230 231 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
231 232 if (UsePerfData)
232 233 counters->update_full_follows_scavenge(0);
233 234 if (!scavenge_was_done ||
234 235 policy->should_full_GC(heap->old_gen()->free_in_bytes())) {
235 236 if (UsePerfData)
236 237 counters->update_full_follows_scavenge(full_follows_scavenge);
237 238 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
238 239 CollectorPolicy* cp = heap->collector_policy();
239 240 const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
240 241
241 242 if (UseParallelOldGC) {
242 243 PSParallelCompact::invoke_no_policy(clear_all_softrefs);
243 244 } else {
244 245 PSMarkSweep::invoke_no_policy(clear_all_softrefs);
245 246 }
246 247 }
247 248 }
248 249
249 250 // This method contains no policy. You should probably
250 251 // be calling invoke() instead.
251 252 bool PSScavenge::invoke_no_policy() {
252 253 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
253 254 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
254 255
255 256 assert(_preserved_mark_stack.is_empty(), "should be empty");
256 257 assert(_preserved_oop_stack.is_empty(), "should be empty");
257 258
258 259 TimeStamp scavenge_entry;
259 260 TimeStamp scavenge_midpoint;
260 261 TimeStamp scavenge_exit;
261 262
262 263 scavenge_entry.update();
263 264
264 265 if (GC_locker::check_active_before_gc()) {
265 266 return false;
266 267 }
267 268
268 269 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
269 270 GCCause::Cause gc_cause = heap->gc_cause();
270 271 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
271 272
272 273 // Check for potential problems.
273 274 if (!should_attempt_scavenge()) {
274 275 return false;
275 276 }
276 277
277 278 bool promotion_failure_occurred = false;
278 279
279 280 PSYoungGen* young_gen = heap->young_gen();
280 281 PSOldGen* old_gen = heap->old_gen();
281 282 PSPermGen* perm_gen = heap->perm_gen();
282 283 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
283 284 heap->increment_total_collections();
284 285
285 286 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
286 287
287 288 if ((gc_cause != GCCause::_java_lang_system_gc) ||
288 289 UseAdaptiveSizePolicyWithSystemGC) {
289 290 // Gather the feedback data for eden occupancy.
290 291 young_gen->eden_space()->accumulate_statistics();
291 292 }
292 293
293 294 if (ZapUnusedHeapArea) {
294 295 // Save information needed to minimize mangling
295 296 heap->record_gen_tops_before_GC();
296 297 }
297 298
298 299 heap->print_heap_before_gc();
299 300
300 301 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity");
301 302 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity");
302 303
303 304 size_t prev_used = heap->used();
304 305 assert(promotion_failed() == false, "Sanity");
305 306
306 307 // Fill in TLABs
307 308 heap->accumulate_statistics_all_tlabs();
308 309 heap->ensure_parsability(true); // retire TLABs
309 310
310 311 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
311 312 HandleMark hm; // Discard invalid handles created during verification
312 313 gclog_or_tty->print(" VerifyBeforeGC:");
313 314 Universe::verify(true);
314 315 }
315 316
316 317 {
317 318 ResourceMark rm;
318 319 HandleMark hm;
319 320
320 321 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
321 322 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
322 323 TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty);
323 324 TraceCollectorStats tcs(counters());
324 325 TraceMemoryManagerStats tms(false /* not full GC */,gc_cause);
325 326
326 327 if (TraceGen0Time) accumulated_time()->start();
327 328
328 329 // Let the size policy know we're starting
329 330 size_policy->minor_collection_begin();
330 331
331 332 // Verify the object start arrays.
332 333 if (VerifyObjectStartArray &&
333 334 VerifyBeforeGC) {
334 335 old_gen->verify_object_start_array();
335 336 perm_gen->verify_object_start_array();
336 337 }
337 338
338 339 // Verify no unmarked old->young roots
339 340 if (VerifyRememberedSets) {
340 341 CardTableExtension::verify_all_young_refs_imprecise();
341 342 }
342 343
343 344 if (!ScavengeWithObjectsInToSpace) {
344 345 assert(young_gen->to_space()->is_empty(),
345 346 "Attempt to scavenge with live objects in to_space");
346 347 young_gen->to_space()->clear(SpaceDecorator::Mangle);
347 348 } else if (ZapUnusedHeapArea) {
348 349 young_gen->to_space()->mangle_unused_area();
349 350 }
350 351 save_to_space_top_before_gc();
351 352
352 353 COMPILER2_PRESENT(DerivedPointerTable::clear());
353 354
354 355 reference_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
355 356 reference_processor()->setup_policy(false);
356 357
357 358 // We track how much was promoted to the next generation for
358 359 // the AdaptiveSizePolicy.
359 360 size_t old_gen_used_before = old_gen->used_in_bytes();
360 361
361 362 // For PrintGCDetails
362 363 size_t young_gen_used_before = young_gen->used_in_bytes();
363 364
364 365 // Reset our survivor overflow.
365 366 set_survivor_overflow(false);
366 367
367 368 // We need to save the old/perm top values before
368 369 // creating the promotion_manager. We pass the top
369 370 // values to the card_table, to prevent it from
370 371 // straying into the promotion labs.
371 372 HeapWord* old_top = old_gen->object_space()->top();
372 373 HeapWord* perm_top = perm_gen->object_space()->top();
373 374
374 375 // Release all previously held resources
375 376 gc_task_manager()->release_all_resources();
376 377
377 378 // Set the number of GC threads to be used in this collection
378 379 gc_task_manager()->set_active_gang();
379 380 gc_task_manager()->task_idle_workers();
380 381 // Get the active number of workers here and use that value
381 382 // throughout the methods.
382 383 uint active_workers = gc_task_manager()->active_workers();
383 384 heap->set_par_threads(active_workers);
384 385
385 386 PSPromotionManager::pre_scavenge();
386 387
387 388 // We'll use the promotion manager again later.
388 389 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager();
389 390 {
390 391 // TraceTime("Roots");
391 392 ParallelScavengeHeap::ParStrongRootsScope psrs;
392 393
393 394 GCTaskQueue* q = GCTaskQueue::create();
394 395
395 396 uint stripe_total = active_workers;
396 397 for(uint i=0; i < stripe_total; i++) {
397 398 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total));
398 399 }
399 400
400 401 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top));
401 402
402 403 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe));
403 404 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles));
404 405 // We scan the thread roots in parallel
405 406 Threads::create_thread_roots_tasks(q);
406 407 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer));
407 408 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler));
408 409 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management));
409 410 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary));
410 411 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti));
411 412 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache));
412 413
413 414 ParallelTaskTerminator terminator(
414 415 active_workers,
415 416 (TaskQueueSetSuper*) promotion_manager->stack_array_depth());
416 417 if (active_workers > 1) {
417 418 for (uint j = 0; j < active_workers; j++) {
418 419 q->enqueue(new StealTask(&terminator));
419 420 }
420 421 }
421 422
422 423 gc_task_manager()->execute_and_wait(q);
423 424 }
424 425
425 426 scavenge_midpoint.update();
426 427
427 428 // Process reference objects discovered during scavenge
428 429 {
429 430 reference_processor()->setup_policy(false); // not always_clear
430 431 reference_processor()->set_active_mt_degree(active_workers);
431 432 PSKeepAliveClosure keep_alive(promotion_manager);
432 433 PSEvacuateFollowersClosure evac_followers(promotion_manager);
433 434 if (reference_processor()->processing_is_mt()) {
434 435 PSRefProcTaskExecutor task_executor;
435 436 reference_processor()->process_discovered_references(
436 437 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor);
437 438 } else {
438 439 reference_processor()->process_discovered_references(
439 440 &_is_alive_closure, &keep_alive, &evac_followers, NULL);
440 441 }
441 442 }
442 443
443 444 // Enqueue reference objects discovered during scavenge.
444 445 if (reference_processor()->processing_is_mt()) {
445 446 PSRefProcTaskExecutor task_executor;
446 447 reference_processor()->enqueue_discovered_references(&task_executor);
447 448 } else {
448 449 reference_processor()->enqueue_discovered_references(NULL);
449 450 }
450 451
451 452 if (!JavaObjectsInPerm) {
452 453 // Unlink any dead interned Strings
453 454 StringTable::unlink(&_is_alive_closure);
454 455 // Process the remaining live ones
455 456 PSScavengeRootsClosure root_closure(promotion_manager);
456 457 StringTable::oops_do(&root_closure);
457 458 }
458 459
459 460 // Finally, flush the promotion_manager's labs, and deallocate its stacks.
460 461 PSPromotionManager::post_scavenge();
461 462
462 463 promotion_failure_occurred = promotion_failed();
463 464 if (promotion_failure_occurred) {
464 465 clean_up_failed_promotion();
465 466 if (PrintGC) {
466 467 gclog_or_tty->print("--");
467 468 }
468 469 }
469 470
470 471 // Let the size policy know we're done. Note that we count promotion
471 472 // failure cleanup time as part of the collection (otherwise, we're
472 473 // implicitly saying it's mutator time).
473 474 size_policy->minor_collection_end(gc_cause);
474 475
475 476 if (!promotion_failure_occurred) {
476 477 // Swap the survivor spaces.
477 478
478 479
479 480 young_gen->eden_space()->clear(SpaceDecorator::Mangle);
480 481 young_gen->from_space()->clear(SpaceDecorator::Mangle);
481 482 young_gen->swap_spaces();
482 483
483 484 size_t survived = young_gen->from_space()->used_in_bytes();
484 485 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before;
485 486 size_policy->update_averages(_survivor_overflow, survived, promoted);
486 487
487 488 // A successful scavenge should restart the GC time limit count which is
488 489 // for full GC's.
489 490 size_policy->reset_gc_overhead_limit_count();
490 491 if (UseAdaptiveSizePolicy) {
491 492 // Calculate the new survivor size and tenuring threshold
492 493
493 494 if (PrintAdaptiveSizePolicy) {
494 495 gclog_or_tty->print("AdaptiveSizeStart: ");
495 496 gclog_or_tty->stamp();
496 497 gclog_or_tty->print_cr(" collection: %d ",
497 498 heap->total_collections());
498 499
499 500 if (Verbose) {
500 501 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
501 502 " perm_gen_capacity: %d ",
502 503 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
503 504 perm_gen->capacity_in_bytes());
504 505 }
505 506 }
506 507
507 508
508 509 if (UsePerfData) {
509 510 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
510 511 counters->update_old_eden_size(
511 512 size_policy->calculated_eden_size_in_bytes());
512 513 counters->update_old_promo_size(
513 514 size_policy->calculated_promo_size_in_bytes());
514 515 counters->update_old_capacity(old_gen->capacity_in_bytes());
515 516 counters->update_young_capacity(young_gen->capacity_in_bytes());
516 517 counters->update_survived(survived);
517 518 counters->update_promoted(promoted);
518 519 counters->update_survivor_overflowed(_survivor_overflow);
519 520 }
520 521
521 522 size_t survivor_limit =
522 523 size_policy->max_survivor_size(young_gen->max_size());
523 524 _tenuring_threshold =
524 525 size_policy->compute_survivor_space_size_and_threshold(
525 526 _survivor_overflow,
526 527 _tenuring_threshold,
527 528 survivor_limit);
528 529
529 530 if (PrintTenuringDistribution) {
530 531 gclog_or_tty->cr();
531 532 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)",
532 533 size_policy->calculated_survivor_size_in_bytes(),
533 534 _tenuring_threshold, MaxTenuringThreshold);
534 535 }
535 536
536 537 if (UsePerfData) {
537 538 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
538 539 counters->update_tenuring_threshold(_tenuring_threshold);
539 540 counters->update_survivor_size_counters();
540 541 }
541 542
542 543 // Do call at minor collections?
543 544 // Don't check if the size_policy is ready at this
544 545 // level. Let the size_policy check that internally.
545 546 if (UseAdaptiveSizePolicy &&
546 547 UseAdaptiveGenerationSizePolicyAtMinorCollection &&
547 548 ((gc_cause != GCCause::_java_lang_system_gc) ||
548 549 UseAdaptiveSizePolicyWithSystemGC)) {
549 550
550 551 // Calculate optimial free space amounts
551 552 assert(young_gen->max_size() >
552 553 young_gen->from_space()->capacity_in_bytes() +
553 554 young_gen->to_space()->capacity_in_bytes(),
554 555 "Sizes of space in young gen are out-of-bounds");
555 556 size_t max_eden_size = young_gen->max_size() -
556 557 young_gen->from_space()->capacity_in_bytes() -
557 558 young_gen->to_space()->capacity_in_bytes();
558 559 size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
559 560 young_gen->eden_space()->used_in_bytes(),
560 561 old_gen->used_in_bytes(),
561 562 perm_gen->used_in_bytes(),
562 563 young_gen->eden_space()->capacity_in_bytes(),
563 564 old_gen->max_gen_size(),
564 565 max_eden_size,
565 566 false /* full gc*/,
566 567 gc_cause,
567 568 heap->collector_policy());
568 569
569 570 }
570 571 // Resize the young generation at every collection
571 572 // even if new sizes have not been calculated. This is
572 573 // to allow resizes that may have been inhibited by the
573 574 // relative location of the "to" and "from" spaces.
574 575
575 576 // Resizing the old gen at minor collects can cause increases
576 577 // that don't feed back to the generation sizing policy until
577 578 // a major collection. Don't resize the old gen here.
578 579
579 580 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
580 581 size_policy->calculated_survivor_size_in_bytes());
581 582
582 583 if (PrintAdaptiveSizePolicy) {
583 584 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
584 585 heap->total_collections());
585 586 }
586 587 }
587 588
588 589 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can
589 590 // cause the change of the heap layout. Make sure eden is reshaped if that's the case.
590 591 // Also update() will case adaptive NUMA chunk resizing.
591 592 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now");
592 593 young_gen->eden_space()->update();
593 594
594 595 heap->gc_policy_counters()->update_counters();
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595 596
596 597 heap->resize_all_tlabs();
597 598
598 599 assert(young_gen->to_space()->is_empty(), "to space should be empty now");
599 600 }
600 601
601 602 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
602 603
603 604 NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
604 605
606 + CodeCache::prune_scavenge_root_nmethods();
607 +
605 608 // Re-verify object start arrays
606 609 if (VerifyObjectStartArray &&
607 610 VerifyAfterGC) {
608 611 old_gen->verify_object_start_array();
609 612 perm_gen->verify_object_start_array();
610 613 }
611 614
612 615 // Verify all old -> young cards are now precise
613 616 if (VerifyRememberedSets) {
614 617 // Precise verification will give false positives. Until this is fixed,
615 618 // use imprecise verification.
616 619 // CardTableExtension::verify_all_young_refs_precise();
617 620 CardTableExtension::verify_all_young_refs_imprecise();
618 621 }
619 622
620 623 if (TraceGen0Time) accumulated_time()->stop();
621 624
622 625 if (PrintGC) {
623 626 if (PrintGCDetails) {
624 627 // Don't print a GC timestamp here. This is after the GC so
625 628 // would be confusing.
626 629 young_gen->print_used_change(young_gen_used_before);
627 630 }
628 631 heap->print_heap_change(prev_used);
629 632 }
630 633
631 634 // Track memory usage and detect low memory
632 635 MemoryService::track_memory_usage();
633 636 heap->update_counters();
634 637
635 638 gc_task_manager()->release_idle_workers();
636 639 }
637 640
638 641 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
639 642 HandleMark hm; // Discard invalid handles created during verification
640 643 gclog_or_tty->print(" VerifyAfterGC:");
641 644 Universe::verify(false);
642 645 }
643 646
644 647 heap->print_heap_after_gc();
645 648
646 649 if (ZapUnusedHeapArea) {
647 650 young_gen->eden_space()->check_mangled_unused_area_complete();
648 651 young_gen->from_space()->check_mangled_unused_area_complete();
649 652 young_gen->to_space()->check_mangled_unused_area_complete();
650 653 }
651 654
652 655 scavenge_exit.update();
653 656
654 657 if (PrintGCTaskTimeStamps) {
655 658 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT,
656 659 scavenge_entry.ticks(), scavenge_midpoint.ticks(),
657 660 scavenge_exit.ticks());
658 661 gc_task_manager()->print_task_time_stamps();
659 662 }
660 663
661 664 #ifdef TRACESPINNING
662 665 ParallelTaskTerminator::print_termination_counts();
663 666 #endif
664 667
665 668 return !promotion_failure_occurred;
666 669 }
667 670
668 671 // This method iterates over all objects in the young generation,
669 672 // unforwarding markOops. It then restores any preserved mark oops,
670 673 // and clears the _preserved_mark_stack.
671 674 void PSScavenge::clean_up_failed_promotion() {
672 675 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
673 676 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
674 677 assert(promotion_failed(), "Sanity");
675 678
676 679 PSYoungGen* young_gen = heap->young_gen();
677 680
678 681 {
679 682 ResourceMark rm;
680 683
681 684 // Unforward all pointers in the young gen.
682 685 PSPromotionFailedClosure unforward_closure;
683 686 young_gen->object_iterate(&unforward_closure);
684 687
685 688 if (PrintGC && Verbose) {
686 689 gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size());
687 690 }
688 691
689 692 // Restore any saved marks.
690 693 while (!_preserved_oop_stack.is_empty()) {
691 694 oop obj = _preserved_oop_stack.pop();
692 695 markOop mark = _preserved_mark_stack.pop();
693 696 obj->set_mark(mark);
694 697 }
695 698
696 699 // Clear the preserved mark and oop stack caches.
697 700 _preserved_mark_stack.clear(true);
698 701 _preserved_oop_stack.clear(true);
699 702 _promotion_failed = false;
700 703 }
701 704
702 705 // Reset the PromotionFailureALot counters.
703 706 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
704 707 }
705 708
706 709 // This method is called whenever an attempt to promote an object
707 710 // fails. Some markOops will need preservation, some will not. Note
708 711 // that the entire eden is traversed after a failed promotion, with
709 712 // all forwarded headers replaced by the default markOop. This means
710 713 // it is not neccessary to preserve most markOops.
711 714 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) {
712 715 _promotion_failed = true;
713 716 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) {
714 717 // Should use per-worker private stakcs hetre rather than
715 718 // locking a common pair of stacks.
716 719 ThreadCritical tc;
717 720 _preserved_oop_stack.push(obj);
718 721 _preserved_mark_stack.push(obj_mark);
719 722 }
720 723 }
721 724
722 725 bool PSScavenge::should_attempt_scavenge() {
723 726 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
724 727 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
725 728 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
726 729
727 730 if (UsePerfData) {
728 731 counters->update_scavenge_skipped(not_skipped);
729 732 }
730 733
731 734 PSYoungGen* young_gen = heap->young_gen();
732 735 PSOldGen* old_gen = heap->old_gen();
733 736
734 737 if (!ScavengeWithObjectsInToSpace) {
735 738 // Do not attempt to promote unless to_space is empty
736 739 if (!young_gen->to_space()->is_empty()) {
737 740 _consecutive_skipped_scavenges++;
738 741 if (UsePerfData) {
739 742 counters->update_scavenge_skipped(to_space_not_empty);
740 743 }
741 744 return false;
742 745 }
743 746 }
744 747
745 748 // Test to see if the scavenge will likely fail.
746 749 PSAdaptiveSizePolicy* policy = heap->size_policy();
747 750
748 751 // A similar test is done in the policy's should_full_GC(). If this is
749 752 // changed, decide if that test should also be changed.
750 753 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
751 754 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
752 755 bool result = promotion_estimate < old_gen->free_in_bytes();
753 756
754 757 if (PrintGCDetails && Verbose) {
755 758 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: ");
756 759 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
757 760 " padded_average_promoted " SIZE_FORMAT
758 761 " free in old gen " SIZE_FORMAT,
759 762 (size_t) policy->average_promoted_in_bytes(),
760 763 (size_t) policy->padded_average_promoted_in_bytes(),
761 764 old_gen->free_in_bytes());
762 765 if (young_gen->used_in_bytes() <
763 766 (size_t) policy->padded_average_promoted_in_bytes()) {
764 767 gclog_or_tty->print_cr(" padded_promoted_average is greater"
765 768 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
766 769 }
767 770 }
768 771
769 772 if (result) {
770 773 _consecutive_skipped_scavenges = 0;
771 774 } else {
772 775 _consecutive_skipped_scavenges++;
773 776 if (UsePerfData) {
774 777 counters->update_scavenge_skipped(promoted_too_large);
775 778 }
776 779 }
777 780 return result;
778 781 }
779 782
780 783 // Used to add tasks
781 784 GCTaskManager* const PSScavenge::gc_task_manager() {
782 785 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
783 786 "shouldn't return NULL");
784 787 return ParallelScavengeHeap::gc_task_manager();
785 788 }
786 789
787 790 void PSScavenge::initialize() {
788 791 // Arguments must have been parsed
789 792
790 793 if (AlwaysTenure) {
791 794 _tenuring_threshold = 0;
792 795 } else if (NeverTenure) {
793 796 _tenuring_threshold = markOopDesc::max_age + 1;
794 797 } else {
795 798 // We want to smooth out our startup times for the AdaptiveSizePolicy
796 799 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
797 800 MaxTenuringThreshold;
798 801 }
799 802
800 803 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
801 804 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
802 805
803 806 PSYoungGen* young_gen = heap->young_gen();
804 807 PSOldGen* old_gen = heap->old_gen();
805 808 PSPermGen* perm_gen = heap->perm_gen();
806 809
807 810 // Set boundary between young_gen and old_gen
808 811 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(),
809 812 "perm above old");
810 813 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
811 814 "old above young");
812 815 _young_generation_boundary = young_gen->eden_space()->bottom();
813 816
814 817 // Initialize ref handling object for scavenging.
815 818 MemRegion mr = young_gen->reserved();
816 819
817 820 _ref_processor =
818 821 new ReferenceProcessor(mr, // span
819 822 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
820 823 (int) ParallelGCThreads, // mt processing degree
821 824 true, // mt discovery
822 825 (int) ParallelGCThreads, // mt discovery degree
823 826 true, // atomic_discovery
824 827 NULL, // header provides liveness info
825 828 false); // next field updates do not need write barrier
826 829
827 830 // Cache the cardtable
828 831 BarrierSet* bs = Universe::heap()->barrier_set();
829 832 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
830 833 _card_table = (CardTableExtension*)bs;
831 834
832 835 _counters = new CollectorCounters("PSScavenge", 0);
833 836 }
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