1 /* 2 * Copyright (c) 2014, 2015, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "code/codeCache.hpp" 25 #include "gc/shared/gcTraceTime.inline.hpp" 26 #include "gc/shared/isGCActiveMark.hpp" 27 #include "gc/shenandoah/brooksPointer.hpp" 28 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 29 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" 30 #include "gc/shenandoah/shenandoahMarkCompact.hpp" 31 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 32 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 33 #include "gc/shenandoah/shenandoahHeap.hpp" 34 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 35 #include "gc/shenandoah/shenandoahRootProcessor.hpp" 36 #include "gc/shenandoah/vm_operations_shenandoah.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "runtime/biasedLocking.hpp" 39 #include "runtime/thread.hpp" 40 #include "utilities/copy.hpp" 41 #include "gc/shared/taskqueue.inline.hpp" 42 #include "gc/shared/workgroup.hpp" 43 44 class ShenandoahMarkCompactBarrierSet : public ShenandoahBarrierSet { 45 public: 46 ShenandoahMarkCompactBarrierSet(ShenandoahHeap* heap) : ShenandoahBarrierSet(heap) { 47 } 48 oop read_barrier(oop src) { 49 return src; 50 } 51 #ifdef ASSERT 52 bool is_safe(oop o) { 53 if (o == NULL) return true; 54 if (! oopDesc::unsafe_equals(o, read_barrier(o))) { 55 return false; 56 } 57 return true; 58 } 59 bool is_safe(narrowOop o) { 60 oop obj = oopDesc::decode_heap_oop(o); 61 return is_safe(obj); 62 } 63 #endif 64 }; 65 66 class ClearInCollectionSetHeapRegionClosure: public ShenandoahHeapRegionClosure { 67 private: 68 ShenandoahHeap* _heap; 69 public: 70 71 ClearInCollectionSetHeapRegionClosure() : _heap(ShenandoahHeap::heap()) { 72 } 73 74 bool doHeapRegion(ShenandoahHeapRegion* r) { 75 _heap->set_next_top_at_mark_start(r->bottom(), r->top()); 76 r->clear_live_data(); 77 r->set_concurrent_iteration_safe_limit(r->top()); 78 return false; 79 } 80 }; 81 82 STWGCTimer* ShenandoahMarkCompact::_gc_timer = NULL; 83 84 void ShenandoahMarkCompact::initialize() { 85 _gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer(); 86 } 87 88 void ShenandoahMarkCompact::do_mark_compact(GCCause::Cause gc_cause) { 89 90 ShenandoahHeap* _heap = ShenandoahHeap::heap(); 91 ShenandoahCollectorPolicy* policy = _heap->shenandoahPolicy(); 92 93 _gc_timer->register_gc_start(); 94 95 _heap->set_full_gc_in_progress(true); 96 97 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 98 IsGCActiveMark is_active; 99 100 assert(Thread::current()->is_VM_thread(), "Do full GC only while world is stopped"); 101 102 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc); 103 104 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_heapdumps); 105 _heap->pre_full_gc_dump(_gc_timer); 106 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_heapdumps); 107 108 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_prepare); 109 110 // Full GC is supposed to recover from any GC state: 111 112 // a. Cancel concurrent mark, if in progress 113 if (_heap->concurrent_mark_in_progress()) { 114 _heap->concurrentMark()->cancel(); 115 _heap->stop_concurrent_marking(); 116 } 117 assert(!_heap->concurrent_mark_in_progress(), "sanity"); 118 119 // b. Cancel evacuation, if in progress 120 if (_heap->is_evacuation_in_progress()) { 121 _heap->set_evacuation_in_progress_at_safepoint(false); 122 } 123 assert(!_heap->is_evacuation_in_progress(), "sanity"); 124 125 // c. Reset the bitmaps for new marking 126 _heap->reset_next_mark_bitmap(_heap->workers()); 127 assert(_heap->is_next_bitmap_clear(), "sanity"); 128 129 ClearInCollectionSetHeapRegionClosure cl; 130 _heap->heap_region_iterate(&cl, false, false); 131 132 /* 133 if (ShenandoahVerify) { 134 // Full GC should only be called between regular concurrent cycles, therefore 135 // those verifications should be valid. 136 _heap->verify_heap_after_evacuation(); 137 _heap->verify_heap_after_update_refs(); 138 } 139 */ 140 141 BarrierSet* old_bs = oopDesc::bs(); 142 ShenandoahMarkCompactBarrierSet bs(_heap); 143 oopDesc::set_bs(&bs); 144 145 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_prepare); 146 147 { 148 GCTraceTime(Info, gc) time("Pause Full", _gc_timer, gc_cause, true); 149 150 if (UseTLAB) { 151 _heap->ensure_parsability(true); 152 } 153 154 CodeCache::gc_prologue(); 155 156 // We should save the marks of the currently locked biased monitors. 157 // The marking doesn't preserve the marks of biased objects. 158 //BiasedLocking::preserve_marks(); 159 160 _heap->set_need_update_refs(true); 161 WorkGang* workers = _heap->workers(); 162 163 // Setup workers for phase 1 164 { 165 uint nworkers = ShenandoahCollectorPolicy::calc_workers_for_init_marking( 166 workers->active_workers(), Threads::number_of_non_daemon_threads()); 167 workers->update_active_workers(nworkers); 168 ShenandoahWorkerScope scope(workers, nworkers); 169 170 OrderAccess::fence(); 171 172 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_mark); 173 phase1_mark_heap(); 174 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_mark); 175 } 176 177 // Setup workers for the rest 178 { 179 uint nworkers = ShenandoahCollectorPolicy::calc_workers_for_parallel_evacuation( 180 workers->active_workers(), Threads::number_of_non_daemon_threads()); 181 182 ShenandoahWorkerScope scope(workers, nworkers); 183 184 OrderAccess::fence(); 185 186 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_calculate_addresses); 187 ShenandoahHeapRegionSet* copy_queues[_heap->max_workers()]; 188 phase2_calculate_target_addresses(copy_queues); 189 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_calculate_addresses); 190 191 OrderAccess::fence(); 192 193 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_adjust_pointers); 194 phase3_update_references(); 195 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_adjust_pointers); 196 197 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_copy_objects); 198 phase4_compact_objects(copy_queues); 199 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_copy_objects); 200 201 CodeCache::gc_epilogue(); 202 JvmtiExport::gc_epilogue(); 203 } 204 205 // refs processing: clean slate 206 // rp.enqueue_discovered_references(); 207 208 if (ShenandoahVerify) { 209 _heap->verify_heap_after_evacuation(); 210 } 211 212 _heap->set_bytes_allocated_since_cm(0); 213 214 _heap->set_need_update_refs(false); 215 216 _heap->set_full_gc_in_progress(false); 217 } 218 219 _gc_timer->register_gc_end(); 220 221 policy->record_full_gc(); 222 223 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_heapdumps); 224 _heap->post_full_gc_dump(_gc_timer); 225 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_heapdumps); 226 227 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc); 228 229 oopDesc::set_bs(old_bs); 230 231 if (UseShenandoahMatrix) { 232 if (PrintShenandoahMatrix) { 233 outputStream* log = Log(gc)::info_stream(); 234 _heap->connection_matrix()->print_on(log); 235 } 236 } 237 } 238 239 #ifdef ASSERT 240 class VerifyNotForwardedPointersClosure : public MetadataAwareOopClosure { 241 private: 242 template <class T> 243 inline void do_oop_work(T* p) { 244 T o = oopDesc::load_heap_oop(p); 245 if (! oopDesc::is_null(o)) { 246 oop obj = oopDesc::decode_heap_oop_not_null(o); 247 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), 248 "expect forwarded oop"); 249 ShenandoahHeap* heap = ShenandoahHeap::heap(); 250 if (! heap->is_marked_complete(obj)) { 251 tty->print_cr("ref region humongous? %s", BOOL_TO_STR(heap->heap_region_containing(p)->is_humongous())); 252 } 253 assert(heap->is_marked_complete(obj), "must be marked"); 254 assert(! heap->allocated_after_complete_mark_start((HeapWord*) obj), "must be truly marked"); 255 } 256 } 257 public: 258 void do_oop(oop* p) { 259 do_oop_work(p); 260 } 261 void do_oop(narrowOop* p) { 262 do_oop_work(p); 263 } 264 }; 265 266 class ShenandoahMCVerifyAfterMarkingObjectClosure : public ObjectClosure { 267 public: 268 void do_object(oop p) { 269 ShenandoahHeap* heap = ShenandoahHeap::heap(); 270 assert(oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p)), 271 "expect forwarded oop"); 272 assert(heap->is_marked_complete(p), "must be marked"); 273 assert(! heap->allocated_after_complete_mark_start((HeapWord*) p), "must be truly marked"); 274 VerifyNotForwardedPointersClosure cl; 275 p->oop_iterate(&cl); 276 } 277 }; 278 279 class ShenandoahMCVerifyAfterMarkingRegionClosure : public ShenandoahHeapRegionClosure { 280 bool doHeapRegion(ShenandoahHeapRegion* r) { 281 ShenandoahMCVerifyAfterMarkingObjectClosure cl; 282 if (! r->is_humongous_continuation()) { 283 ShenandoahHeap::heap()->marked_object_iterate(r, &cl); 284 } 285 return false; 286 } 287 }; 288 289 #endif 290 291 void ShenandoahMarkCompact::phase1_mark_heap() { 292 GCTraceTime(Info, gc, phases) time("Phase 1: Mark live objects", _gc_timer); 293 ShenandoahHeap* _heap = ShenandoahHeap::heap(); 294 295 ShenandoahConcurrentMark* cm = _heap->concurrentMark(); 296 297 cm->set_process_references(true); 298 cm->set_unload_classes(true); 299 300 ReferenceProcessor* rp = _heap->ref_processor(); 301 // enable ("weak") refs discovery 302 rp->enable_discovery(true /*verify_no_refs*/); 303 rp->setup_policy(true); // snapshot the soft ref policy to be used in this cycle 304 rp->set_active_mt_degree(_heap->workers()->active_workers()); 305 306 COMPILER2_PRESENT(DerivedPointerTable::clear()); 307 cm->update_roots(); 308 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 309 310 cm->mark_roots(); 311 cm->shared_finish_mark_from_roots(/* full_gc = */ true); 312 313 _heap->swap_mark_bitmaps(); 314 315 if (UseShenandoahMatrix) { 316 if (PrintShenandoahMatrix) { 317 outputStream* log = Log(gc)::info_stream(); 318 _heap->connection_matrix()->print_on(log); 319 } 320 } 321 322 if (ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix)) { 323 _heap->verify_heap_reachable_at_safepoint(); 324 } 325 326 if (VerifyDuringGC) { 327 HandleMark hm; // handle scope 328 // Universe::heap()->prepare_for_verify(); 329 _heap->prepare_for_verify(); 330 // Note: we can verify only the heap here. When an object is 331 // marked, the previous value of the mark word (including 332 // identity hash values, ages, etc) is preserved, and the mark 333 // word is set to markOop::marked_value - effectively removing 334 // any hash values from the mark word. These hash values are 335 // used when verifying the dictionaries and so removing them 336 // from the mark word can make verification of the dictionaries 337 // fail. At the end of the GC, the original mark word values 338 // (including hash values) are restored to the appropriate 339 // objects. 340 // Universe::heap()->verify(VerifySilently, VerifyOption_G1UseMarkWord); 341 _heap->verify(VerifyOption_G1UseMarkWord); 342 } 343 344 #ifdef ASSERT 345 ShenandoahMCVerifyAfterMarkingRegionClosure cl; 346 _heap->heap_region_iterate(&cl); 347 #endif 348 } 349 350 class ShenandoahMCReclaimHumongousRegionClosure : public ShenandoahHeapRegionClosure { 351 private: 352 ShenandoahHeap* _heap; 353 public: 354 ShenandoahMCReclaimHumongousRegionClosure() : _heap(ShenandoahHeap::heap()) { 355 } 356 357 bool doHeapRegion(ShenandoahHeapRegion* r) { 358 if (r->is_humongous_start()) { 359 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size()); 360 if (! _heap->is_marked_complete(humongous_obj)) { 361 _heap->reclaim_humongous_region_at(r); 362 } 363 } 364 return false; 365 } 366 }; 367 368 369 class ShenandoahPrepareForCompactionObjectClosure : public ObjectClosure { 370 371 private: 372 373 ShenandoahHeap* _heap; 374 ShenandoahHeapRegionSet* _to_regions; 375 ShenandoahHeapRegion* _to_region; 376 ShenandoahHeapRegion* _from_region; 377 HeapWord* _compact_point; 378 379 public: 380 381 ShenandoahPrepareForCompactionObjectClosure(ShenandoahHeapRegionSet* to_regions, ShenandoahHeapRegion* to_region) : 382 _heap(ShenandoahHeap::heap()), 383 _to_regions(to_regions), 384 _to_region(to_region), 385 _from_region(NULL), 386 _compact_point(to_region->bottom()) { 387 } 388 389 void set_from_region(ShenandoahHeapRegion* from_region) { 390 _from_region = from_region; 391 } 392 393 ShenandoahHeapRegion* to_region() const { 394 return _to_region; 395 } 396 HeapWord* compact_point() const { 397 return _compact_point; 398 } 399 void do_object(oop p) { 400 assert(_from_region != NULL, "must set before work"); 401 assert(_heap->is_marked_complete(p), "must be marked"); 402 assert(! _heap->allocated_after_complete_mark_start((HeapWord*) p), "must be truly marked"); 403 size_t size = p->size(); 404 size_t obj_size = size + BrooksPointer::word_size(); 405 if (_compact_point + obj_size > _to_region->end()) { 406 // Object doesn't fit. Pick next to-region and start compacting there. 407 _to_region->set_new_top(_compact_point); 408 ShenandoahHeapRegion* new_to_region = _to_regions->current(); 409 _to_regions->next(); 410 if (new_to_region == NULL) { 411 new_to_region = _from_region; 412 } 413 assert(new_to_region != _to_region, "must not reuse same to-region"); 414 assert(new_to_region != NULL, "must not be NULL"); 415 _to_region = new_to_region; 416 _compact_point = _to_region->bottom(); 417 } 418 assert(_compact_point + obj_size <= _to_region->end(), "must fit"); 419 assert(oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p)), 420 "expect forwarded oop"); 421 BrooksPointer::set_raw(p, _compact_point + BrooksPointer::word_size()); 422 _compact_point += obj_size; 423 } 424 }; 425 426 class ShenandoahPrepareForCompactionTask : public AbstractGangTask { 427 private: 428 429 ShenandoahHeapRegionSet** _copy_queues; 430 ShenandoahHeapRegionSet* _from_regions; 431 432 ShenandoahHeapRegion* next_from_region(ShenandoahHeapRegionSet* copy_queue) { 433 ShenandoahHeapRegion* from_region = _from_regions->claim_next(); 434 while (from_region != NULL && (from_region->is_humongous() || from_region->is_pinned())) { 435 from_region = _from_regions->claim_next(); 436 } 437 if (from_region != NULL) { 438 assert(copy_queue != NULL, "sanity"); 439 assert(! from_region->is_humongous(), "must not get humongous regions here"); 440 assert(! from_region->is_pinned(), "no pinned region in mark-compact"); 441 copy_queue->add_region(from_region); 442 } 443 return from_region; 444 } 445 446 public: 447 ShenandoahPrepareForCompactionTask(ShenandoahHeapRegionSet* from_regions, ShenandoahHeapRegionSet** copy_queues) : 448 AbstractGangTask("Shenandoah Prepare For Compaction Task"), 449 _from_regions(from_regions), _copy_queues(copy_queues) { 450 } 451 452 void work(uint worker_id) { 453 ShenandoahHeap* heap = ShenandoahHeap::heap(); 454 ShenandoahHeapRegionSet* copy_queue = _copy_queues[worker_id]; 455 ShenandoahHeapRegion* from_region = next_from_region(copy_queue); 456 if (from_region == NULL) return; 457 ShenandoahHeapRegionSet* to_regions = new ShenandoahHeapRegionSet(ShenandoahHeap::heap()->max_regions()); 458 ShenandoahPrepareForCompactionObjectClosure cl(to_regions, from_region); 459 while (from_region != NULL) { 460 assert(from_region != NULL, "sanity"); 461 cl.set_from_region(from_region); 462 heap->marked_object_iterate(from_region, &cl); 463 if (from_region != cl.to_region()) { 464 assert(from_region != NULL, "sanity"); 465 to_regions->add_region(from_region); 466 } 467 from_region = next_from_region(copy_queue); 468 } 469 assert(cl.to_region() != NULL, "should not happen"); 470 cl.to_region()->set_new_top(cl.compact_point()); 471 while (to_regions->count() > 0) { 472 ShenandoahHeapRegion* r = to_regions->current(); 473 to_regions->next(); 474 if (r == NULL) { 475 to_regions->print(); 476 } 477 assert(r != NULL, "should not happen"); 478 r->set_new_top(r->bottom()); 479 } 480 delete to_regions; 481 } 482 }; 483 484 void ShenandoahMarkCompact::phase2_calculate_target_addresses(ShenandoahHeapRegionSet** copy_queues) { 485 GCTraceTime(Info, gc, phases) time("Phase 2: Compute new object addresses", _gc_timer); 486 ShenandoahHeap* heap = ShenandoahHeap::heap(); 487 488 ShenandoahMCReclaimHumongousRegionClosure cl; 489 heap->heap_region_iterate(&cl); 490 491 // Initialize copy queues. 492 for (uint i = 0; i < heap->max_workers(); i++) { 493 copy_queues[i] = new ShenandoahHeapRegionSet(heap->max_regions()); 494 } 495 496 ShenandoahHeapRegionSet* from_regions = heap->regions(); 497 from_regions->clear_current_index(); 498 ShenandoahPrepareForCompactionTask prepare_task(from_regions, copy_queues); 499 heap->workers()->run_task(&prepare_task); 500 } 501 502 class ShenandoahAdjustPointersClosure : public MetadataAwareOopClosure { 503 private: 504 ShenandoahHeap* _heap; 505 size_t _new_obj_offset; 506 public: 507 508 ShenandoahAdjustPointersClosure() : _heap(ShenandoahHeap::heap()) { 509 } 510 511 private: 512 template <class T> 513 inline void do_oop_work(T* p) { 514 T o = oopDesc::load_heap_oop(p); 515 if (! oopDesc::is_null(o)) { 516 oop obj = oopDesc::decode_heap_oop_not_null(o); 517 assert(_heap->is_marked_complete(obj), "must be marked"); 518 oop forw = oop(BrooksPointer::get_raw(obj)); 519 oopDesc::encode_store_heap_oop(p, forw); 520 if (UseShenandoahMatrix) { 521 if (_heap->is_in_reserved(p)) { 522 assert(_heap->is_in_reserved(forw), "must be in heap"); 523 _heap->connection_matrix()->set_connected(((HeapWord*) p) - _new_obj_offset, forw); 524 } 525 } 526 } 527 } 528 public: 529 void do_oop(oop* p) { 530 do_oop_work(p); 531 } 532 void do_oop(narrowOop* p) { 533 do_oop_work(p); 534 } 535 void set_new_obj_offset(size_t new_obj_offset) { 536 _new_obj_offset = new_obj_offset; 537 } 538 }; 539 540 class ShenandoahAdjustPointersObjectClosure : public ObjectClosure { 541 private: 542 ShenandoahAdjustPointersClosure _cl; 543 ShenandoahHeap* _heap; 544 public: 545 ShenandoahAdjustPointersObjectClosure() : 546 _heap(ShenandoahHeap::heap()) { 547 } 548 void do_object(oop p) { 549 assert(_heap->is_marked_complete(p), "must be marked"); 550 HeapWord* forw = BrooksPointer::get_raw(p); 551 _cl.set_new_obj_offset(pointer_delta((HeapWord*) p, forw)); 552 p->oop_iterate(&_cl); 553 } 554 }; 555 556 class ShenandoahAdjustPointersTask : public AbstractGangTask { 557 private: 558 ShenandoahHeapRegionSet* _regions; 559 public: 560 561 ShenandoahAdjustPointersTask(ShenandoahHeapRegionSet* regions) : 562 AbstractGangTask("Shenandoah Adjust Pointers Task"), 563 _regions(regions) { 564 } 565 566 void work(uint worker_id) { 567 ShenandoahHeap* heap = ShenandoahHeap::heap(); 568 ShenandoahHeapRegion* r = _regions->claim_next(); 569 ShenandoahAdjustPointersObjectClosure obj_cl; 570 while (r != NULL) { 571 if (! r->is_humongous_continuation()) { 572 heap->marked_object_iterate(r, &obj_cl); 573 } 574 r = _regions->claim_next(); 575 } 576 } 577 }; 578 579 class ShenandoahAdjustRootPointersTask : public AbstractGangTask { 580 private: 581 ShenandoahRootProcessor* _rp; 582 583 public: 584 585 ShenandoahAdjustRootPointersTask(ShenandoahRootProcessor* rp) : 586 AbstractGangTask("Shenandoah Adjust Root Pointers Task"), 587 _rp(rp) { 588 } 589 590 void work(uint worker_id) { 591 ShenandoahAdjustPointersClosure cl; 592 CLDToOopClosure adjust_cld_closure(&cl, true); 593 MarkingCodeBlobClosure adjust_code_closure(&cl, 594 CodeBlobToOopClosure::FixRelocations); 595 596 _rp->process_all_roots(&cl, &cl, 597 &adjust_cld_closure, 598 &adjust_code_closure, worker_id); 599 } 600 }; 601 602 void ShenandoahMarkCompact::phase3_update_references() { 603 GCTraceTime(Info, gc, phases) time("Phase 2: Adjust pointers", _gc_timer); 604 ShenandoahHeap* heap = ShenandoahHeap::heap(); 605 606 if (UseShenandoahMatrix) { 607 heap->connection_matrix()->clear_all(); 608 } 609 610 // Need cleared claim bits for the roots processing 611 ClassLoaderDataGraph::clear_claimed_marks(); 612 613 WorkGang* workers = heap->workers(); 614 uint nworkers = workers->active_workers(); 615 { 616 COMPILER2_PRESENT(DerivedPointerTable::clear()); 617 618 ShenandoahRootProcessor rp(heap, nworkers); 619 ShenandoahAdjustRootPointersTask task(&rp); 620 workers->run_task(&task); 621 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 622 } 623 624 ShenandoahHeapRegionSet* regions = heap->regions(); 625 regions->clear_current_index(); 626 ShenandoahAdjustPointersTask adjust_pointers_task(regions); 627 workers->run_task(&adjust_pointers_task); 628 } 629 630 class ShenandoahCompactObjectsClosure : public ObjectClosure { 631 private: 632 ShenandoahHeap* _heap; 633 public: 634 ShenandoahCompactObjectsClosure() : _heap(ShenandoahHeap::heap()) { 635 } 636 void do_object(oop p) { 637 assert(_heap->is_marked_complete(p), "must be marked"); 638 size_t size = p->size(); 639 HeapWord* compact_to = BrooksPointer::get_raw(p); 640 HeapWord* compact_from = (HeapWord*) p; 641 if (compact_from != compact_to) { 642 Copy::aligned_conjoint_words(compact_from, compact_to, size); 643 } 644 oop new_obj = oop(compact_to); 645 // new_obj->init_mark(); 646 BrooksPointer::initialize(new_obj); 647 } 648 }; 649 650 class ShenandoahCompactObjectsTask : public AbstractGangTask { 651 ShenandoahHeapRegionSet** _regions; 652 public: 653 ShenandoahCompactObjectsTask(ShenandoahHeapRegionSet** regions) : 654 AbstractGangTask("Shenandoah Compact Objects Task"), 655 _regions(regions) { 656 } 657 void work(uint worker_id) { 658 ShenandoahHeap* heap = ShenandoahHeap::heap(); 659 ShenandoahHeapRegionSet* copy_queue = _regions[worker_id]; 660 copy_queue->clear_current_index(); 661 ShenandoahCompactObjectsClosure cl; 662 ShenandoahHeapRegion* r = copy_queue->current(); 663 copy_queue->next(); 664 while (r != NULL) { 665 assert(! r->is_humongous(), "must not get humongous regions here"); 666 heap->marked_object_iterate(r, &cl); 667 r->set_top(r->new_top()); 668 r = copy_queue->current(); 669 copy_queue->next(); 670 } 671 } 672 }; 673 674 class ShenandoahPostCompactClosure : public ShenandoahHeapRegionClosure { 675 size_t _live; 676 ShenandoahHeap* _heap; 677 public: 678 679 ShenandoahPostCompactClosure() : _live(0), _heap(ShenandoahHeap::heap()) { 680 _heap->clear_free_regions(); 681 } 682 683 bool doHeapRegion(ShenandoahHeapRegion* r) { 684 // Need to reset the complete-top-at-mark-start pointer here because 685 // the complete marking bitmap is no longer valid. This ensures 686 // size-based iteration in marked_object_iterate(). 687 _heap->set_complete_top_at_mark_start(r->bottom(), r->bottom()); 688 r->set_in_collection_set(false); 689 if (r->is_humongous()) { 690 _live += ShenandoahHeapRegion::RegionSizeBytes; 691 } else { 692 size_t live = r->used(); 693 if (live == 0) { 694 r->recycle(); 695 _heap->add_free_region(r); 696 } 697 r->set_live_data(live); 698 _live += live; 699 } 700 return false; 701 } 702 703 size_t get_live() { return _live; } 704 705 }; 706 707 void ShenandoahMarkCompact::phase4_compact_objects(ShenandoahHeapRegionSet** copy_queues) { 708 GCTraceTime(Info, gc, phases) time("Phase 4: Move objects", _gc_timer); 709 ShenandoahHeap* heap = ShenandoahHeap::heap(); 710 ShenandoahCompactObjectsTask compact_task(copy_queues); 711 heap->workers()->run_task(&compact_task); 712 713 heap->clear_cset_fast_test(); 714 715 // Reset complete bitmap. We're about to reset the complete-top-at-mark-start pointer 716 // and must ensure the bitmap is in sync. 717 heap->reset_complete_mark_bitmap(heap->workers()); 718 719 { 720 ShenandoahHeap::ShenandoahHeapLock lock(heap); 721 ShenandoahPostCompactClosure post_compact; 722 heap->heap_region_iterate(&post_compact); 723 724 heap->set_used(post_compact.get_live()); 725 726 } 727 728 heap->clear_cancelled_concgc(); 729 730 // Also clear the next bitmap in preparation for next marking. 731 heap->reset_next_mark_bitmap(heap->workers()); 732 733 for (uint i = 0; i < heap->max_workers(); i++) { 734 delete copy_queues[i]; 735 } 736 737 }