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 "precompiled.hpp"
25 #include "code/codeCache.hpp"
26 #include "gc/shared/gcTraceTime.inline.hpp"
27 #include "gc/shared/isGCActiveMark.hpp"
28 #include "gc/shenandoah/brooksPointer.hpp"
29 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
30 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
31 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
32 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
34 #include "gc/shenandoah/shenandoahHeap.hpp"
35 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
36 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
37 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/biasedLocking.hpp"
40 #include "runtime/thread.hpp"
41 #include "utilities/copy.hpp"
42 #include "gc/shared/taskqueue.inline.hpp"
43 #include "gc/shared/workgroup.hpp"
44
45 class ShenandoahMarkCompactBarrierSet : public ShenandoahBarrierSet {
46 public:
47 ShenandoahMarkCompactBarrierSet(ShenandoahHeap* heap) : ShenandoahBarrierSet(heap) {
48 }
49 oop read_barrier(oop src) {
50 return src;
51 }
52 #ifdef ASSERT
53 bool is_safe(oop o) {
54 if (o == NULL) return true;
55 if (! oopDesc::unsafe_equals(o, read_barrier(o))) {
56 return false;
57 }
58 return true;
59 }
60 bool is_safe(narrowOop o) {
61 oop obj = oopDesc::decode_heap_oop(o);
62 return is_safe(obj);
63 }
64 #endif
65 };
66
67 class ClearInCollectionSetHeapRegionClosure: public ShenandoahHeapRegionClosure {
68 private:
69 ShenandoahHeap* _heap;
70 public:
71
72 ClearInCollectionSetHeapRegionClosure() : _heap(ShenandoahHeap::heap()) {
73 }
74
75 bool doHeapRegion(ShenandoahHeapRegion* r) {
76 _heap->set_next_top_at_mark_start(r->bottom(), r->top());
77 r->clear_live_data();
78 r->set_concurrent_iteration_safe_limit(r->top());
79 return false;
80 }
81 };
82
83 STWGCTimer* ShenandoahMarkCompact::_gc_timer = NULL;
84
85 void ShenandoahMarkCompact::initialize() {
86 _gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
87 }
88
89 void ShenandoahMarkCompact::do_mark_compact(GCCause::Cause gc_cause) {
90
91 ShenandoahHeap* _heap = ShenandoahHeap::heap();
92 ShenandoahCollectorPolicy* policy = _heap->shenandoahPolicy();
93
94 _gc_timer->register_gc_start();
95
96 _heap->set_full_gc_in_progress(true);
97
98 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
99 IsGCActiveMark is_active;
100
101 assert(Thread::current()->is_VM_thread(), "Do full GC only while world is stopped");
102
103 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc);
104
105 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_heapdumps);
106 _heap->pre_full_gc_dump(_gc_timer);
107 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_heapdumps);
108
109 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_prepare);
110
111 // Full GC is supposed to recover from any GC state:
112
113 // a. Cancel concurrent mark, if in progress
114 if (_heap->concurrent_mark_in_progress()) {
115 _heap->concurrentMark()->cancel();
116 _heap->stop_concurrent_marking();
117 }
118 assert(!_heap->concurrent_mark_in_progress(), "sanity");
119
120 // b. Cancel evacuation, if in progress
121 if (_heap->is_evacuation_in_progress()) {
122 _heap->set_evacuation_in_progress_at_safepoint(false);
123 }
124 assert(!_heap->is_evacuation_in_progress(), "sanity");
125
126 // c. Reset the bitmaps for new marking
127 _heap->reset_next_mark_bitmap(_heap->workers());
128 assert(_heap->is_next_bitmap_clear(), "sanity");
129
130 ClearInCollectionSetHeapRegionClosure cl;
131 _heap->heap_region_iterate(&cl, false, false);
132
133 /*
134 if (ShenandoahVerify) {
135 // Full GC should only be called between regular concurrent cycles, therefore
136 // those verifications should be valid.
137 _heap->verify_heap_after_evacuation();
138 _heap->verify_heap_after_update_refs();
139 }
140 */
141
142 BarrierSet* old_bs = oopDesc::bs();
143 ShenandoahMarkCompactBarrierSet bs(_heap);
144 oopDesc::set_bs(&bs);
145
146 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_prepare);
147
148 {
149 GCTraceTime(Info, gc) time("Pause Full", _gc_timer, gc_cause, true);
150
151 if (UseTLAB) {
152 _heap->ensure_parsability(true);
153 }
154
155 CodeCache::gc_prologue();
156
157 // We should save the marks of the currently locked biased monitors.
158 // The marking doesn't preserve the marks of biased objects.
159 //BiasedLocking::preserve_marks();
160
161 _heap->set_need_update_refs(true);
162 WorkGang* workers = _heap->workers();
163
164 // Setup workers for phase 1
165 {
166 uint nworkers = ShenandoahCollectorPolicy::calc_workers_for_init_marking(
167 workers->active_workers(), (uint) Threads::number_of_non_daemon_threads());
168 workers->update_active_workers(nworkers);
169 ShenandoahWorkerScope scope(workers, nworkers);
170
171 OrderAccess::fence();
172
173 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_mark);
174 phase1_mark_heap();
175 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_mark);
176 }
177
178 // Setup workers for the rest
179 {
180 uint nworkers = ShenandoahCollectorPolicy::calc_workers_for_parallel_evacuation(
181 workers->active_workers(), (uint)Threads::number_of_non_daemon_threads());
182 ShenandoahWorkerScope scope(workers, nworkers);
183
184 OrderAccess::fence();
185
186 ShenandoahHeapRegionSet** copy_queues = NEW_C_HEAP_ARRAY(ShenandoahHeapRegionSet*, _heap->max_workers(), mtGC);
187
188 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_calculate_addresses);
189 phase2_calculate_target_addresses(copy_queues);
190 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_calculate_addresses);
191
192 OrderAccess::fence();
193
194 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_adjust_pointers);
195 phase3_update_references();
196 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_adjust_pointers);
197
198 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_copy_objects);
199 phase4_compact_objects(copy_queues);
200 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_copy_objects);
201
202 FREE_C_HEAP_ARRAY(ShenandoahHeapRegionSet*, copy_queues);
203
204 CodeCache::gc_epilogue();
205 JvmtiExport::gc_epilogue();
206 }
207
208 // refs processing: clean slate
209 // rp.enqueue_discovered_references();
210
211 if (ShenandoahVerify) {
212 _heap->verify_heap_after_evacuation();
213 }
214
215 _heap->set_bytes_allocated_since_cm(0);
216
217 _heap->set_need_update_refs(false);
218
219 _heap->set_full_gc_in_progress(false);
220 }
221
222 _gc_timer->register_gc_end();
223
224 policy->record_full_gc();
225
226 policy->record_phase_start(ShenandoahCollectorPolicy::full_gc_heapdumps);
227 _heap->post_full_gc_dump(_gc_timer);
228 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc_heapdumps);
229
230 policy->record_phase_end(ShenandoahCollectorPolicy::full_gc);
231
232 oopDesc::set_bs(old_bs);
233
234 if (UseShenandoahMatrix && PrintShenandoahMatrix) {
235 outputStream* log = Log(gc)::info_stream();
236 _heap->connection_matrix()->print_on(log);
237 }
238 }
239
240 #ifdef ASSERT
241 class VerifyNotForwardedPointersClosure : public MetadataAwareOopClosure {
242 private:
243 template <class T>
244 inline void do_oop_work(T* p) {
245 T o = oopDesc::load_heap_oop(p);
246 if (! oopDesc::is_null(o)) {
247 oop obj = oopDesc::decode_heap_oop_not_null(o);
248 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
249 "expect forwarded oop");
250 ShenandoahHeap* heap = ShenandoahHeap::heap();
251 if (! heap->is_marked_complete(obj)) {
252 tty->print_cr("ref region humongous? %s", BOOL_TO_STR(heap->heap_region_containing(p)->is_humongous()));
253 }
254 assert(heap->is_marked_complete(obj), "must be marked");
255 assert(! heap->allocated_after_complete_mark_start((HeapWord*) obj), "must be truly marked");
256 }
257 }
258 public:
259 void do_oop(oop* p) {
260 do_oop_work(p);
261 }
262 void do_oop(narrowOop* p) {
263 do_oop_work(p);
264 }
265 };
266
267 class ShenandoahMCVerifyAfterMarkingObjectClosure : public ObjectClosure {
268 public:
269 void do_object(oop p) {
270 ShenandoahHeap* heap = ShenandoahHeap::heap();
271 assert(oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p)),
272 "expect forwarded oop");
273 assert(heap->is_marked_complete(p), "must be marked");
274 assert(! heap->allocated_after_complete_mark_start((HeapWord*) p), "must be truly marked");
275 VerifyNotForwardedPointersClosure cl;
276 p->oop_iterate(&cl);
277 }
278 };
279
280 class ShenandoahMCVerifyAfterMarkingRegionClosure : public ShenandoahHeapRegionClosure {
281 bool doHeapRegion(ShenandoahHeapRegion* r) {
282 ShenandoahMCVerifyAfterMarkingObjectClosure cl;
283 if (! r->is_humongous_continuation()) {
284 ShenandoahHeap::heap()->marked_object_iterate(r, &cl);
285 }
286 return false;
287 }
288 };
289
290 #endif
291
292 void ShenandoahMarkCompact::phase1_mark_heap() {
293 GCTraceTime(Info, gc, phases) time("Phase 1: Mark live objects", _gc_timer);
294 ShenandoahHeap* _heap = ShenandoahHeap::heap();
295
296 ShenandoahConcurrentMark* cm = _heap->concurrentMark();
297
298 cm->set_process_references(true);
299 cm->set_unload_classes(true);
300
301 ReferenceProcessor* rp = _heap->ref_processor();
302 // enable ("weak") refs discovery
303 rp->enable_discovery(true /*verify_no_refs*/);
304 rp->setup_policy(true); // snapshot the soft ref policy to be used in this cycle
305 rp->set_active_mt_degree(_heap->workers()->active_workers());
306
307 COMPILER2_PRESENT(DerivedPointerTable::clear());
308 cm->update_roots();
309 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
310
311 cm->mark_roots();
312 cm->shared_finish_mark_from_roots(/* full_gc = */ true);
313
314 _heap->swap_mark_bitmaps();
315
316 if (UseShenandoahMatrix && PrintShenandoahMatrix) {
317 outputStream* log = Log(gc)::info_stream();
318 _heap->connection_matrix()->print_on(log);
319 }
320
321 if (ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix)) {
322 _heap->verify_heap_reachable_at_safepoint();
323 }
324
325 if (VerifyDuringGC) {
326 HandleMark hm; // handle scope
327 // Universe::heap()->prepare_for_verify();
328 _heap->prepare_for_verify();
329 // Note: we can verify only the heap here. When an object is
330 // marked, the previous value of the mark word (including
331 // identity hash values, ages, etc) is preserved, and the mark
332 // word is set to markOop::marked_value - effectively removing
333 // any hash values from the mark word. These hash values are
334 // used when verifying the dictionaries and so removing them
335 // from the mark word can make verification of the dictionaries
336 // fail. At the end of the GC, the original mark word values
337 // (including hash values) are restored to the appropriate
338 // objects.
339 // Universe::heap()->verify(VerifySilently, VerifyOption_G1UseMarkWord);
340 _heap->verify(VerifyOption_G1UseMarkWord);
341 }
342
343 #ifdef ASSERT
344 ShenandoahMCVerifyAfterMarkingRegionClosure cl;
345 _heap->heap_region_iterate(&cl);
346 #endif
347 }
348
349 class ShenandoahMCReclaimHumongousRegionClosure : public ShenandoahHeapRegionClosure {
350 private:
351 ShenandoahHeap* _heap;
352 public:
353 ShenandoahMCReclaimHumongousRegionClosure() : _heap(ShenandoahHeap::heap()) {
354 }
355
356 bool doHeapRegion(ShenandoahHeapRegion* r) {
357 if (r->is_humongous_start()) {
358 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size());
359 if (! _heap->is_marked_complete(humongous_obj)) {
360 _heap->reclaim_humongous_region_at(r);
361 }
362 }
363 return false;
364 }
365 };
366
367
368 class ShenandoahPrepareForCompactionObjectClosure : public ObjectClosure {
369
370 private:
371
372 ShenandoahHeap* _heap;
373 ShenandoahHeapRegionSet* _to_regions;
374 ShenandoahHeapRegion* _to_region;
375 ShenandoahHeapRegion* _from_region;
376 HeapWord* _compact_point;
377
378 public:
379
380 ShenandoahPrepareForCompactionObjectClosure(ShenandoahHeapRegionSet* to_regions, ShenandoahHeapRegion* to_region) :
381 _heap(ShenandoahHeap::heap()),
382 _to_regions(to_regions),
383 _to_region(to_region),
384 _from_region(NULL),
385 _compact_point(to_region->bottom()) {
386 }
387
388 void set_from_region(ShenandoahHeapRegion* from_region) {
389 _from_region = from_region;
390 }
391
392 ShenandoahHeapRegion* to_region() const {
393 return _to_region;
394 }
395 HeapWord* compact_point() const {
396 return _compact_point;
397 }
398 void do_object(oop p) {
399 assert(_from_region != NULL, "must set before work");
400 assert(_heap->is_marked_complete(p), "must be marked");
401 assert(! _heap->allocated_after_complete_mark_start((HeapWord*) p), "must be truly marked");
402 size_t obj_size = p->size() + BrooksPointer::word_size();
403 if (_compact_point + obj_size > _to_region->end()) {
404 // Object doesn't fit. Pick next to-region and start compacting there.
405 _to_region->set_new_top(_compact_point);
406 ShenandoahHeapRegion* new_to_region = _to_regions->current();
407 _to_regions->next();
408 if (new_to_region == NULL) {
409 new_to_region = _from_region;
410 }
411 assert(new_to_region != _to_region, "must not reuse same to-region");
412 assert(new_to_region != NULL, "must not be NULL");
413 _to_region = new_to_region;
414 _compact_point = _to_region->bottom();
415 }
416 assert(_compact_point + obj_size <= _to_region->end(), "must fit");
417 assert(oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p)),
418 "expect forwarded oop");
419 BrooksPointer::set_raw(p, _compact_point + BrooksPointer::word_size());
420 _compact_point += obj_size;
421 }
422 };
423
424 class ShenandoahPrepareForCompactionTask : public AbstractGangTask {
425 private:
426
427 ShenandoahHeapRegionSet** _copy_queues;
428 ShenandoahHeapRegionSet* _from_regions;
429
430 ShenandoahHeapRegion* next_from_region(ShenandoahHeapRegionSet* copy_queue) {
431 ShenandoahHeapRegion* from_region = _from_regions->claim_next();
432 while (from_region != NULL && (from_region->is_humongous() || from_region->is_pinned())) {
433 from_region = _from_regions->claim_next();
434 }
435 if (from_region != NULL) {
436 assert(copy_queue != NULL, "sanity");
437 assert(! from_region->is_humongous(), "must not get humongous regions here");
438 assert(! from_region->is_pinned(), "no pinned region in mark-compact");
439 copy_queue->add_region(from_region);
440 }
441 return from_region;
442 }
443
444 public:
445 ShenandoahPrepareForCompactionTask(ShenandoahHeapRegionSet* from_regions, ShenandoahHeapRegionSet** copy_queues) :
446 AbstractGangTask("Shenandoah Prepare For Compaction Task"),
447 _from_regions(from_regions), _copy_queues(copy_queues) {
448 }
449
450 void work(uint worker_id) {
451 ShenandoahHeap* heap = ShenandoahHeap::heap();
452 ShenandoahHeapRegionSet* copy_queue = _copy_queues[worker_id];
453 ShenandoahHeapRegion* from_region = next_from_region(copy_queue);
454 if (from_region == NULL) return;
455 ShenandoahHeapRegionSet* to_regions = new ShenandoahHeapRegionSet(ShenandoahHeap::heap()->max_regions());
456 ShenandoahPrepareForCompactionObjectClosure cl(to_regions, from_region);
457 while (from_region != NULL) {
458 assert(from_region != NULL, "sanity");
459 cl.set_from_region(from_region);
460 heap->marked_object_iterate(from_region, &cl);
461 if (from_region != cl.to_region()) {
462 assert(from_region != NULL, "sanity");
463 to_regions->add_region(from_region);
464 }
465 from_region = next_from_region(copy_queue);
466 }
467 assert(cl.to_region() != NULL, "should not happen");
468 cl.to_region()->set_new_top(cl.compact_point());
469 while (to_regions->count() > 0) {
470 ShenandoahHeapRegion* r = to_regions->current();
471 to_regions->next();
472 if (r == NULL) {
473 to_regions->print();
474 }
475 assert(r != NULL, "should not happen");
476 r->set_new_top(r->bottom());
477 }
478 delete to_regions;
479 }
480 };
481
482 void ShenandoahMarkCompact::phase2_calculate_target_addresses(ShenandoahHeapRegionSet** copy_queues) {
483 GCTraceTime(Info, gc, phases) time("Phase 2: Compute new object addresses", _gc_timer);
484 ShenandoahHeap* heap = ShenandoahHeap::heap();
485
486 ShenandoahMCReclaimHumongousRegionClosure cl;
487 heap->heap_region_iterate(&cl);
488
489 // Initialize copy queues.
490 for (uint i = 0; i < heap->max_workers(); i++) {
491 copy_queues[i] = new ShenandoahHeapRegionSet(heap->max_regions());
492 }
493
494 ShenandoahHeapRegionSet* from_regions = heap->regions();
495 from_regions->clear_current_index();
496 ShenandoahPrepareForCompactionTask prepare_task(from_regions, copy_queues);
497 heap->workers()->run_task(&prepare_task);
498 }
499
500 class ShenandoahAdjustPointersClosure : public MetadataAwareOopClosure {
501 private:
502 ShenandoahHeap* _heap;
503 size_t _new_obj_offset;
504 public:
505
506 ShenandoahAdjustPointersClosure() : _heap(ShenandoahHeap::heap()) {
507 }
508
509 private:
510 template <class T>
511 inline void do_oop_work(T* p) {
512 T o = oopDesc::load_heap_oop(p);
513 if (! oopDesc::is_null(o)) {
514 oop obj = oopDesc::decode_heap_oop_not_null(o);
515 assert(_heap->is_marked_complete(obj), "must be marked");
516 oop forw = oop(BrooksPointer::get_raw(obj));
517 oopDesc::encode_store_heap_oop(p, forw);
518 if (UseShenandoahMatrix) {
519 if (_heap->is_in_reserved(p)) {
520 assert(_heap->is_in_reserved(forw), "must be in heap");
521 // We're moving a to a', which points to b, about to be moved to b'.
522 // We already know b' from the fwd pointer of b.
523 // In the object closure, we see a, and we know a' (by looking at its
524 // fwd ptr). We store the offset in the OopClosure, which is going
525 // to visit all of a's fields, and then, when we see each field, we
526 // subtract the offset from each field address to get the final ptr.
527 _heap->connection_matrix()->set_connected(((HeapWord*) p) - _new_obj_offset, forw);
528 }
529 }
530 }
531 }
532 public:
533 void do_oop(oop* p) {
534 do_oop_work(p);
535 }
536 void do_oop(narrowOop* p) {
537 do_oop_work(p);
538 }
539 void set_new_obj_offset(size_t new_obj_offset) {
540 _new_obj_offset = new_obj_offset;
541 }
542 };
543
544 class ShenandoahAdjustPointersObjectClosure : public ObjectClosure {
545 private:
546 ShenandoahAdjustPointersClosure _cl;
547 ShenandoahHeap* _heap;
548 public:
549 ShenandoahAdjustPointersObjectClosure() :
550 _heap(ShenandoahHeap::heap()) {
551 }
552 void do_object(oop p) {
553 assert(_heap->is_marked_complete(p), "must be marked");
554 HeapWord* forw = BrooksPointer::get_raw(p);
555 _cl.set_new_obj_offset(pointer_delta((HeapWord*) p, forw));
556 p->oop_iterate(&_cl);
557 }
558 };
559
560 class ShenandoahAdjustPointersTask : public AbstractGangTask {
561 private:
562 ShenandoahHeapRegionSet* _regions;
563 public:
564
565 ShenandoahAdjustPointersTask(ShenandoahHeapRegionSet* regions) :
566 AbstractGangTask("Shenandoah Adjust Pointers Task"),
567 _regions(regions) {
568 }
569
570 void work(uint worker_id) {
571 ShenandoahHeap* heap = ShenandoahHeap::heap();
572 ShenandoahHeapRegion* r = _regions->claim_next();
573 ShenandoahAdjustPointersObjectClosure obj_cl;
574 while (r != NULL) {
575 if (! r->is_humongous_continuation()) {
576 heap->marked_object_iterate(r, &obj_cl);
577 }
578 r = _regions->claim_next();
579 }
580 }
581 };
582
583 class ShenandoahAdjustRootPointersTask : public AbstractGangTask {
584 private:
585 ShenandoahRootProcessor* _rp;
586
587 public:
588
589 ShenandoahAdjustRootPointersTask(ShenandoahRootProcessor* rp) :
590 AbstractGangTask("Shenandoah Adjust Root Pointers Task"),
591 _rp(rp) {
592 }
593
594 void work(uint worker_id) {
595 ShenandoahAdjustPointersClosure cl;
596 CLDToOopClosure adjust_cld_closure(&cl, true);
597 MarkingCodeBlobClosure adjust_code_closure(&cl,
598 CodeBlobToOopClosure::FixRelocations);
599
600 _rp->process_all_roots(&cl, &cl,
601 &adjust_cld_closure,
602 &adjust_code_closure, worker_id);
603 }
604 };
605
606 void ShenandoahMarkCompact::phase3_update_references() {
607 GCTraceTime(Info, gc, phases) time("Phase 2: Adjust pointers", _gc_timer);
608 ShenandoahHeap* heap = ShenandoahHeap::heap();
609
610 if (UseShenandoahMatrix) {
611 heap->connection_matrix()->clear_all();
612 }
613
614 // Need cleared claim bits for the roots processing
615 ClassLoaderDataGraph::clear_claimed_marks();
616
617 WorkGang* workers = heap->workers();
618 uint nworkers = workers->active_workers();
619 {
620 COMPILER2_PRESENT(DerivedPointerTable::clear());
621
622 ShenandoahRootProcessor rp(heap, nworkers);
623 ShenandoahAdjustRootPointersTask task(&rp);
624 workers->run_task(&task);
625 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
626 }
627
628 ShenandoahHeapRegionSet* regions = heap->regions();
629 regions->clear_current_index();
630 ShenandoahAdjustPointersTask adjust_pointers_task(regions);
631 workers->run_task(&adjust_pointers_task);
632 }
633
634 class ShenandoahCompactObjectsClosure : public ObjectClosure {
635 private:
636 ShenandoahHeap* _heap;
637 public:
638 ShenandoahCompactObjectsClosure() : _heap(ShenandoahHeap::heap()) {
639 }
640 void do_object(oop p) {
641 assert(_heap->is_marked_complete(p), "must be marked");
642 size_t size = (size_t)p->size();
643 HeapWord* compact_to = BrooksPointer::get_raw(p);
644 HeapWord* compact_from = (HeapWord*) p;
645 if (compact_from != compact_to) {
646 Copy::aligned_conjoint_words(compact_from, compact_to, size);
647 }
648 oop new_obj = oop(compact_to);
649 // new_obj->init_mark();
650 BrooksPointer::initialize(new_obj);
651 }
652 };
653
654 class ShenandoahCompactObjectsTask : public AbstractGangTask {
655 ShenandoahHeapRegionSet** _regions;
656 public:
657 ShenandoahCompactObjectsTask(ShenandoahHeapRegionSet** regions) :
658 AbstractGangTask("Shenandoah Compact Objects Task"),
659 _regions(regions) {
660 }
661 void work(uint worker_id) {
662 ShenandoahHeap* heap = ShenandoahHeap::heap();
663 ShenandoahHeapRegionSet* copy_queue = _regions[worker_id];
664 copy_queue->clear_current_index();
665 ShenandoahCompactObjectsClosure cl;
666 ShenandoahHeapRegion* r = copy_queue->current();
667 copy_queue->next();
668 while (r != NULL) {
669 assert(! r->is_humongous(), "must not get humongous regions here");
670 heap->marked_object_iterate(r, &cl);
671 r->set_top(r->new_top());
672 r = copy_queue->current();
673 copy_queue->next();
674 }
675 }
676 };
677
678 class ShenandoahPostCompactClosure : public ShenandoahHeapRegionClosure {
679 size_t _live;
680 ShenandoahHeap* _heap;
681 public:
682
683 ShenandoahPostCompactClosure() : _live(0), _heap(ShenandoahHeap::heap()) {
684 _heap->clear_free_regions();
685 }
686
687 bool doHeapRegion(ShenandoahHeapRegion* r) {
688 // Need to reset the complete-top-at-mark-start pointer here because
689 // the complete marking bitmap is no longer valid. This ensures
690 // size-based iteration in marked_object_iterate().
691 _heap->set_complete_top_at_mark_start(r->bottom(), r->bottom());
692 r->set_in_collection_set(false);
693 if (r->is_humongous()) {
694 _live += ShenandoahHeapRegion::region_size_bytes();
695 } else {
696 size_t live = r->used();
697 if (live == 0) {
698 r->recycle();
699 _heap->add_free_region(r);
700 }
701 r->set_live_data(live);
702 _live += live;
703 }
704 return false;
705 }
706
707 size_t get_live() { return _live; }
708
709 };
710
711 void ShenandoahMarkCompact::phase4_compact_objects(ShenandoahHeapRegionSet** copy_queues) {
712 GCTraceTime(Info, gc, phases) time("Phase 4: Move objects", _gc_timer);
713 ShenandoahHeap* heap = ShenandoahHeap::heap();
714 ShenandoahCompactObjectsTask compact_task(copy_queues);
715 heap->workers()->run_task(&compact_task);
716
717 heap->clear_cset_fast_test();
718
719 // Reset complete bitmap. We're about to reset the complete-top-at-mark-start pointer
720 // and must ensure the bitmap is in sync.
721 heap->reset_complete_mark_bitmap(heap->workers());
722
723 {
724 ShenandoahHeap::ShenandoahHeapLock lock(heap);
725 ShenandoahPostCompactClosure post_compact;
726 heap->heap_region_iterate(&post_compact);
727
728 heap->set_used(post_compact.get_live());
729
730 }
731
732 heap->clear_cancelled_concgc();
733
734 // Also clear the next bitmap in preparation for next marking.
735 heap->reset_next_mark_bitmap(heap->workers());
736
737 for (uint i = 0; i < heap->max_workers(); i++) {
738 delete copy_queues[i];
739 }
740
741 }