1 /*
2 * Copyright (c) 2017, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "classfile/classLoaderDataGraph.hpp"
26 #include "classfile/stringTable.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/oopMap.hpp"
31 #include "gc/serial/cardTableRS.hpp"
32 #include "gc/serial/serialFullGC.hpp"
33 #include "gc/serial/serialHeap.inline.hpp"
34 #include "gc/serial/serialMemoryPools.hpp"
35 #include "gc/serial/serialVMOperations.hpp"
36 #include "gc/serial/tenuredGeneration.inline.hpp"
37 #include "gc/shared/cardTableBarrierSet.hpp"
38 #include "gc/shared/classUnloadingContext.hpp"
39 #include "gc/shared/collectedHeap.inline.hpp"
40 #include "gc/shared/collectorCounters.hpp"
41 #include "gc/shared/continuationGCSupport.inline.hpp"
42 #include "gc/shared/fullGCForwarding.inline.hpp"
43 #include "gc/shared/gcId.hpp"
44 #include "gc/shared/gcInitLogger.hpp"
45 #include "gc/shared/gcLocker.inline.hpp"
46 #include "gc/shared/gcPolicyCounters.hpp"
47 #include "gc/shared/gcTrace.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/gcVMOperations.hpp"
50 #include "gc/shared/genArguments.hpp"
51 #include "gc/shared/isGCActiveMark.hpp"
52 #include "gc/shared/locationPrinter.inline.hpp"
53 #include "gc/shared/oopStorage.inline.hpp"
54 #include "gc/shared/oopStorageParState.inline.hpp"
55 #include "gc/shared/oopStorageSet.inline.hpp"
56 #include "gc/shared/scavengableNMethods.hpp"
57 #include "gc/shared/space.hpp"
58 #include "gc/shared/strongRootsScope.hpp"
59 #include "gc/shared/suspendibleThreadSet.hpp"
60 #include "gc/shared/weakProcessor.hpp"
61 #include "gc/shared/workerThread.hpp"
62 #include "memory/iterator.hpp"
63 #include "memory/metaspaceCounters.hpp"
64 #include "memory/metaspaceUtils.hpp"
65 #include "memory/reservedSpace.hpp"
66 #include "memory/resourceArea.hpp"
67 #include "memory/universe.hpp"
68 #include "oops/oop.inline.hpp"
69 #include "runtime/handles.hpp"
70 #include "runtime/handles.inline.hpp"
71 #include "runtime/java.hpp"
72 #include "runtime/mutexLocker.hpp"
73 #include "runtime/threads.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "services/memoryManager.hpp"
76 #include "services/memoryService.hpp"
77 #include "utilities/debug.hpp"
78 #include "utilities/formatBuffer.hpp"
79 #include "utilities/macros.hpp"
80 #include "utilities/stack.inline.hpp"
81 #include "utilities/vmError.hpp"
82 #if INCLUDE_JVMCI
83 #include "jvmci/jvmci.hpp"
84 #endif
85
86 SerialHeap* SerialHeap::heap() {
87 return named_heap<SerialHeap>(CollectedHeap::Serial);
88 }
89
90 SerialHeap::SerialHeap() :
91 CollectedHeap(),
92 _young_gen(nullptr),
93 _old_gen(nullptr),
94 _rem_set(nullptr),
95 _gc_policy_counters(new GCPolicyCounters("Copy:MSC", 2, 2)),
96 _young_manager(nullptr),
97 _old_manager(nullptr),
98 _is_heap_almost_full(false),
99 _eden_pool(nullptr),
100 _survivor_pool(nullptr),
101 _old_pool(nullptr) {
102 _young_manager = new GCMemoryManager("Copy");
103 _old_manager = new GCMemoryManager("MarkSweepCompact");
104 GCLocker::initialize();
105 }
106
107 void SerialHeap::initialize_serviceability() {
108 DefNewGeneration* young = young_gen();
109
110 // Add a memory pool for each space and young gen doesn't
111 // support low memory detection as it is expected to get filled up.
112 _eden_pool = new ContiguousSpacePool(young->eden(),
113 "Eden Space",
114 young->max_eden_size(),
115 false /* support_usage_threshold */);
116 _survivor_pool = new SurvivorContiguousSpacePool(young,
117 "Survivor Space",
118 young->max_survivor_size(),
119 false /* support_usage_threshold */);
120 TenuredGeneration* old = old_gen();
121 _old_pool = new TenuredGenerationPool(old, "Tenured Gen", true);
122
123 _young_manager->add_pool(_eden_pool);
124 _young_manager->add_pool(_survivor_pool);
125 young->set_gc_manager(_young_manager);
126
127 _old_manager->add_pool(_eden_pool);
128 _old_manager->add_pool(_survivor_pool);
129 _old_manager->add_pool(_old_pool);
130 old->set_gc_manager(_old_manager);
131 }
132
133 GrowableArray<GCMemoryManager*> SerialHeap::memory_managers() {
134 GrowableArray<GCMemoryManager*> memory_managers(2);
135 memory_managers.append(_young_manager);
136 memory_managers.append(_old_manager);
137 return memory_managers;
138 }
139
140 GrowableArray<MemoryPool*> SerialHeap::memory_pools() {
141 GrowableArray<MemoryPool*> memory_pools(3);
142 memory_pools.append(_eden_pool);
143 memory_pools.append(_survivor_pool);
144 memory_pools.append(_old_pool);
145 return memory_pools;
146 }
147
148 void SerialHeap::safepoint_synchronize_begin() {
149 if (UseStringDeduplication) {
150 SuspendibleThreadSet::synchronize();
151 }
152 }
153
154 void SerialHeap::safepoint_synchronize_end() {
155 if (UseStringDeduplication) {
156 SuspendibleThreadSet::desynchronize();
157 }
158 }
159
160 HeapWord* SerialHeap::allocate_loaded_archive_space(size_t word_size) {
161 MutexLocker ml(Heap_lock);
162 return old_gen()->allocate(word_size);
163 }
164
165 void SerialHeap::complete_loaded_archive_space(MemRegion archive_space) {
166 assert(old_gen()->used_region().contains(archive_space), "Archive space not contained in old gen");
167 old_gen()->complete_loaded_archive_space(archive_space);
168 }
169
170 void SerialHeap::pin_object(JavaThread* thread, oop obj) {
171 GCLocker::enter(thread);
172 }
173
174 void SerialHeap::unpin_object(JavaThread* thread, oop obj) {
175 GCLocker::exit(thread);
176 }
177
178 jint SerialHeap::initialize() {
179 // Allocate space for the heap.
180
181 ReservedHeapSpace heap_rs = allocate(HeapAlignment);
182
183 if (!heap_rs.is_reserved()) {
184 vm_shutdown_during_initialization(
185 "Could not reserve enough space for object heap");
186 return JNI_ENOMEM;
187 }
188
189 initialize_reserved_region(heap_rs);
190
191 ReservedSpace young_rs = heap_rs.first_part(MaxNewSize, SpaceAlignment);
192 ReservedSpace old_rs = heap_rs.last_part(MaxNewSize, SpaceAlignment);
193
194 _rem_set = new CardTableRS(_reserved);
195 _rem_set->initialize(young_rs.base(), old_rs.base());
196
197 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set);
198 bs->initialize();
199 BarrierSet::set_barrier_set(bs);
200
201 _young_gen = new DefNewGeneration(young_rs, NewSize, MinNewSize, MaxNewSize);
202 _old_gen = new TenuredGeneration(old_rs, OldSize, MinOldSize, MaxOldSize, rem_set());
203
204 GCInitLogger::print();
205
206 FullGCForwarding::initialize(_reserved);
207
208 return JNI_OK;
209 }
210
211 ReservedHeapSpace SerialHeap::allocate(size_t alignment) {
212 // Now figure out the total size.
213 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
214 assert(alignment % pageSize == 0, "Must be");
215
216 // Check for overflow.
217 size_t total_reserved = MaxNewSize + MaxOldSize;
218 if (total_reserved < MaxNewSize) {
219 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
220 "the maximum representable size");
221 }
222 assert(total_reserved % alignment == 0,
223 "Gen size; total_reserved=%zu, alignment=%zu", total_reserved, alignment);
224
225 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment);
226 size_t used_page_size = heap_rs.page_size();
227
228 os::trace_page_sizes("Heap",
229 MinHeapSize,
230 total_reserved,
231 heap_rs.base(),
232 heap_rs.size(),
233 used_page_size);
234
235 return heap_rs;
236 }
237
238 class GenIsScavengable : public BoolObjectClosure {
239 public:
240 bool do_object_b(oop obj) {
241 return SerialHeap::heap()->is_in_young(obj);
242 }
243 };
244
245 static GenIsScavengable _is_scavengable;
246
247 void SerialHeap::post_initialize() {
248 CollectedHeap::post_initialize();
249
250 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
251
252 def_new_gen->ref_processor_init();
253
254 SerialFullGC::initialize();
255
256 ScavengableNMethods::initialize(&_is_scavengable);
257 }
258
259 PreGenGCValues SerialHeap::get_pre_gc_values() const {
260 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
261
262 return PreGenGCValues(def_new_gen->used(),
263 def_new_gen->capacity(),
264 def_new_gen->eden()->used(),
265 def_new_gen->eden()->capacity(),
266 def_new_gen->from()->used(),
267 def_new_gen->from()->capacity(),
268 old_gen()->used(),
269 old_gen()->capacity());
270 }
271
272 size_t SerialHeap::capacity() const {
273 return _young_gen->capacity() + _old_gen->capacity();
274 }
275
276 size_t SerialHeap::used() const {
277 return _young_gen->used() + _old_gen->used();
278 }
279
280 size_t SerialHeap::max_capacity() const {
281 return _young_gen->max_capacity() + _old_gen->max_capacity();
282 }
283
284 // Return true if any of the following is true:
285 // . the allocation won't fit into the current young gen heap
286 // . heap memory is tight
287 bool SerialHeap::should_try_older_generation_allocation(size_t word_size) const {
288 size_t young_capacity = _young_gen->capacity_before_gc();
289 return (word_size > heap_word_size(young_capacity))
290 || _is_heap_almost_full;
291 }
292
293 HeapWord* SerialHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
294 HeapWord* result = nullptr;
295 if (_old_gen->should_allocate(size, is_tlab)) {
296 result = _old_gen->expand_and_allocate(size);
297 }
298 if (result == nullptr) {
299 if (_young_gen->should_allocate(size, is_tlab)) {
300 // Young-gen is not expanded.
301 result = _young_gen->allocate(size);
302 }
303 }
304 assert(result == nullptr || is_in_reserved(result), "result not in heap");
305 return result;
306 }
307
308 HeapWord* SerialHeap::mem_allocate_work(size_t size, bool is_tlab) {
309 HeapWord* result = nullptr;
310
311 // Loop until the allocation is satisfied, or unsatisfied after GC.
312 for (uint try_count = 1; /* return or throw */; try_count += 1) {
313 // First allocation attempt is lock-free.
314 DefNewGeneration *young = _young_gen;
315 if (young->should_allocate(size, is_tlab)) {
316 result = young->par_allocate(size);
317 if (result != nullptr) {
318 assert(is_in_reserved(result), "result not in heap");
319 return result;
320 }
321 }
322 uint gc_count_before; // Read inside the Heap_lock locked region.
323 {
324 MutexLocker ml(Heap_lock);
325 log_trace(gc, alloc)("SerialHeap::mem_allocate_work: attempting locked slow path allocation");
326 // Note that only large objects get a shot at being
327 // allocated in later generations.
328 bool first_only = !should_try_older_generation_allocation(size);
329
330 result = attempt_allocation(size, is_tlab, first_only);
331 if (result != nullptr) {
332 assert(is_in_reserved(result), "result not in heap");
333 return result;
334 }
335
336 // Read the gc count while the heap lock is held.
337 gc_count_before = total_collections();
338 }
339
340 VM_SerialCollectForAllocation op(size, is_tlab, gc_count_before);
341 VMThread::execute(&op);
342 if (op.gc_succeeded()) {
343 result = op.result();
344
345 assert(result == nullptr || is_in_reserved(result),
346 "result not in heap");
347 return result;
348 }
349
350 // Give a warning if we seem to be looping forever.
351 if ((QueuedAllocationWarningCount > 0) &&
352 (try_count % QueuedAllocationWarningCount == 0)) {
353 log_warning(gc, ergo)("SerialHeap::mem_allocate_work retries %d times,"
354 " size=%zu %s", try_count, size, is_tlab ? "(TLAB)" : "");
355 }
356 }
357 }
358
359 HeapWord* SerialHeap::attempt_allocation(size_t size,
360 bool is_tlab,
361 bool first_only) {
362 HeapWord* res = nullptr;
363
364 if (_young_gen->should_allocate(size, is_tlab)) {
365 res = _young_gen->allocate(size);
366 if (res != nullptr || first_only) {
367 return res;
368 }
369 }
370
371 if (_old_gen->should_allocate(size, is_tlab)) {
372 res = _old_gen->allocate(size);
373 }
374
375 return res;
376 }
377
378 HeapWord* SerialHeap::mem_allocate(size_t size,
379 bool* gc_overhead_limit_was_exceeded) {
380 return mem_allocate_work(size,
381 false /* is_tlab */);
382 }
383
384 bool SerialHeap::must_clear_all_soft_refs() {
385 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
386 _gc_cause == GCCause::_wb_full_gc;
387 }
388
389 bool SerialHeap::is_young_gc_safe() const {
390 if (!_young_gen->to()->is_empty()) {
391 return false;
392 }
393 return _old_gen->promotion_attempt_is_safe(_young_gen->used());
394 }
395
396 bool SerialHeap::do_young_collection(bool clear_soft_refs) {
397 if (!is_young_gc_safe()) {
398 return false;
399 }
400 IsSTWGCActiveMark gc_active_mark;
401 SvcGCMarker sgcm(SvcGCMarker::MINOR);
402 GCIdMark gc_id_mark;
403 GCTraceCPUTime tcpu(_young_gen->gc_tracer());
404 GCTraceTime(Info, gc) t("Pause Young", nullptr, gc_cause(), true);
405 TraceCollectorStats tcs(_young_gen->counters());
406 TraceMemoryManagerStats tmms(_young_gen->gc_manager(), gc_cause(), "end of minor GC");
407 print_before_gc();
408 const PreGenGCValues pre_gc_values = get_pre_gc_values();
409
410 increment_total_collections(false);
411 const bool should_verify = total_collections() >= VerifyGCStartAt;
412 if (should_verify && VerifyBeforeGC) {
413 prepare_for_verify();
414 Universe::verify("Before GC");
415 }
416 gc_prologue();
417 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
418
419 save_marks();
420
421 bool result = _young_gen->collect(clear_soft_refs);
422
423 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
424
425 // Only update stats for successful young-gc
426 if (result) {
427 _old_gen->update_promote_stats();
428 }
429
430 if (should_verify && VerifyAfterGC) {
431 Universe::verify("After GC");
432 }
433
434 _young_gen->compute_new_size();
435
436 print_heap_change(pre_gc_values);
437
438 // Track memory usage and detect low memory after GC finishes
439 MemoryService::track_memory_usage();
440
441 gc_epilogue(false);
442
443 print_after_gc();
444
445 return result;
446 }
447
448 void SerialHeap::register_nmethod(nmethod* nm) {
449 ScavengableNMethods::register_nmethod(nm);
450 }
451
452 void SerialHeap::unregister_nmethod(nmethod* nm) {
453 ScavengableNMethods::unregister_nmethod(nm);
454 }
455
456 void SerialHeap::verify_nmethod(nmethod* nm) {
457 ScavengableNMethods::verify_nmethod(nm);
458 }
459
460 void SerialHeap::prune_scavengable_nmethods() {
461 ScavengableNMethods::prune_nmethods_not_into_young();
462 }
463
464 void SerialHeap::prune_unlinked_nmethods() {
465 ScavengableNMethods::prune_unlinked_nmethods();
466 }
467
468 HeapWord* SerialHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
469 assert(size != 0, "precondition");
470
471 HeapWord* result = nullptr;
472
473 // If young-gen can handle this allocation, attempt young-gc firstly.
474 bool should_run_young_gc = _young_gen->should_allocate(size, is_tlab);
475 collect_at_safepoint(!should_run_young_gc);
476
477 result = attempt_allocation(size, is_tlab, false /*first_only*/);
478 if (result != nullptr) {
479 return result;
480 }
481
482 // OK, collection failed, try expansion.
483 result = expand_heap_and_allocate(size, is_tlab);
484 if (result != nullptr) {
485 return result;
486 }
487
488 // If we reach this point, we're really out of memory. Try every trick
489 // we can to reclaim memory. Force collection of soft references. Force
490 // a complete compaction of the heap. Any additional methods for finding
491 // free memory should be here, especially if they are expensive. If this
492 // attempt fails, an OOM exception will be thrown.
493 {
494 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
495 const bool clear_all_soft_refs = true;
496 do_full_collection(clear_all_soft_refs);
497 }
498
499 result = attempt_allocation(size, is_tlab, false /* first_only */);
500 if (result != nullptr) {
501 return result;
502 }
503 // The previous full-gc can shrink the heap, so re-expand it.
504 result = expand_heap_and_allocate(size, is_tlab);
505 if (result != nullptr) {
506 return result;
507 }
508
509 // What else? We might try synchronous finalization later. If the total
510 // space available is large enough for the allocation, then a more
511 // complete compaction phase than we've tried so far might be
512 // appropriate.
513 return nullptr;
514 }
515
516 void SerialHeap::process_roots(ScanningOption so,
517 OopClosure* strong_roots,
518 CLDClosure* strong_cld_closure,
519 CLDClosure* weak_cld_closure,
520 NMethodToOopClosure* code_roots) {
521 // General roots.
522 assert(code_roots != nullptr, "code root closure should always be set");
523
524 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
525
526 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
527 NMethodToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? nullptr : code_roots;
528
529 Threads::oops_do(strong_roots, roots_from_code_p);
530
531 OopStorageSet::strong_oops_do(strong_roots);
532
533 if (so & SO_ScavengeCodeCache) {
534 assert(code_roots != nullptr, "must supply closure for code cache");
535
536 // We only visit parts of the CodeCache when scavenging.
537 ScavengableNMethods::nmethods_do(code_roots);
538 }
539 if (so & SO_AllCodeCache) {
540 assert(code_roots != nullptr, "must supply closure for code cache");
541
542 // CMSCollector uses this to do intermediate-strength collections.
543 // We scan the entire code cache, since CodeCache::do_unloading is not called.
544 CodeCache::nmethods_do(code_roots);
545 }
546 }
547
548 template <typename OopClosureType>
549 static void oop_iterate_from(OopClosureType* blk, ContiguousSpace* space, HeapWord** from) {
550 assert(*from != nullptr, "precondition");
551 HeapWord* t;
552 HeapWord* p = *from;
553
554 const intx interval = PrefetchScanIntervalInBytes;
555 do {
556 t = space->top();
557 while (p < t) {
558 Prefetch::write(p, interval);
559 p += cast_to_oop(p)->oop_iterate_size(blk);
560 }
561 } while (t < space->top());
562
563 *from = space->top();
564 }
565
566 void SerialHeap::scan_evacuated_objs(YoungGenScanClosure* young_cl,
567 OldGenScanClosure* old_cl) {
568 ContiguousSpace* to_space = young_gen()->to();
569 do {
570 oop_iterate_from(young_cl, to_space, &_young_gen_saved_top);
571 oop_iterate_from(old_cl, old_gen()->space(), &_old_gen_saved_top);
572 // Recheck to-space only, because postcondition of oop_iterate_from is no
573 // unscanned objs
574 } while (_young_gen_saved_top != to_space->top());
575 guarantee(young_gen()->promo_failure_scan_is_complete(), "Failed to finish scan");
576 }
577
578 void SerialHeap::collect_at_safepoint(bool full) {
579 assert(!GCLocker::is_active(), "precondition");
580 bool clear_soft_refs = must_clear_all_soft_refs();
581
582 if (!full) {
583 bool success = do_young_collection(clear_soft_refs);
584 if (success) {
585 return;
586 }
587 // Upgrade to Full-GC if young-gc fails
588 }
589 do_full_collection(clear_soft_refs);
590 }
591
592 // public collection interfaces
593 void SerialHeap::collect(GCCause::Cause cause) {
594 // The caller doesn't have the Heap_lock
595 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
596
597 unsigned int gc_count_before;
598 unsigned int full_gc_count_before;
599
600 {
601 MutexLocker ml(Heap_lock);
602 // Read the GC count while holding the Heap_lock
603 gc_count_before = total_collections();
604 full_gc_count_before = total_full_collections();
605 }
606
607 bool should_run_young_gc = (cause == GCCause::_wb_young_gc)
608 DEBUG_ONLY(|| (cause == GCCause::_scavenge_alot));
609
610 VM_SerialGCCollect op(!should_run_young_gc,
611 gc_count_before,
612 full_gc_count_before,
613 cause);
614 VMThread::execute(&op);
615 }
616
617 void SerialHeap::do_full_collection(bool clear_all_soft_refs) {
618 IsSTWGCActiveMark gc_active_mark;
619 SvcGCMarker sgcm(SvcGCMarker::FULL);
620 GCIdMark gc_id_mark;
621 GCTraceCPUTime tcpu(SerialFullGC::gc_tracer());
622 GCTraceTime(Info, gc) t("Pause Full", nullptr, gc_cause(), true);
623 TraceCollectorStats tcs(_old_gen->counters());
624 TraceMemoryManagerStats tmms(_old_gen->gc_manager(), gc_cause(), "end of major GC");
625 const PreGenGCValues pre_gc_values = get_pre_gc_values();
626 print_before_gc();
627
628 increment_total_collections(true);
629 const bool should_verify = total_collections() >= VerifyGCStartAt;
630 if (should_verify && VerifyBeforeGC) {
631 prepare_for_verify();
632 Universe::verify("Before GC");
633 }
634
635 gc_prologue();
636 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
637 CodeCache::on_gc_marking_cycle_start();
638 ClassUnloadingContext ctx(1 /* num_nmethod_unlink_workers */,
639 false /* unregister_nmethods_during_purge */,
640 false /* lock_nmethod_free_separately */);
641
642 STWGCTimer* gc_timer = SerialFullGC::gc_timer();
643 gc_timer->register_gc_start();
644
645 SerialOldTracer* gc_tracer = SerialFullGC::gc_tracer();
646 gc_tracer->report_gc_start(gc_cause(), gc_timer->gc_start());
647
648 pre_full_gc_dump(gc_timer);
649
650 SerialFullGC::invoke_at_safepoint(clear_all_soft_refs);
651
652 post_full_gc_dump(gc_timer);
653
654 gc_timer->register_gc_end();
655
656 gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions());
657 CodeCache::on_gc_marking_cycle_finish();
658 CodeCache::arm_all_nmethods();
659 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
660
661 // Adjust generation sizes.
662 _old_gen->compute_new_size();
663 _young_gen->compute_new_size();
664
665 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
666 ClassLoaderDataGraph::purge(/*at_safepoint*/true);
667 DEBUG_ONLY(MetaspaceUtils::verify();)
668
669 // Need to clear claim bits for the next mark.
670 ClassLoaderDataGraph::clear_claimed_marks();
671
672 _old_gen->update_promote_stats();
673
674 // Resize the metaspace capacity after full collections
675 MetaspaceGC::compute_new_size();
676
677 print_heap_change(pre_gc_values);
678
679 // Track memory usage and detect low memory after GC finishes
680 MemoryService::track_memory_usage();
681
682 // Need to tell the epilogue code we are done with Full GC, regardless what was
683 // the initial value for "complete" flag.
684 gc_epilogue(true);
685
686 print_after_gc();
687
688 if (should_verify && VerifyAfterGC) {
689 Universe::verify("After GC");
690 }
691 }
692
693 bool SerialHeap::is_in_young(const void* p) const {
694 bool result = p < _old_gen->reserved().start();
695 assert(result == _young_gen->is_in_reserved(p),
696 "incorrect test - result=%d, p=" PTR_FORMAT, result, p2i(p));
697 return result;
698 }
699
700 bool SerialHeap::requires_barriers(stackChunkOop obj) const {
701 return !is_in_young(obj);
702 }
703
704 // Returns "TRUE" iff "p" points into the committed areas of the heap.
705 bool SerialHeap::is_in(const void* p) const {
706 return _young_gen->is_in(p) || _old_gen->is_in(p);
707 }
708
709 void SerialHeap::object_iterate(ObjectClosure* cl) {
710 _young_gen->object_iterate(cl);
711 _old_gen->object_iterate(cl);
712 }
713
714 HeapWord* SerialHeap::block_start(const void* addr) const {
715 assert(is_in_reserved(addr), "block_start of address outside of heap");
716 if (_young_gen->is_in_reserved(addr)) {
717 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
718 return _young_gen->block_start(addr);
719 }
720
721 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
722 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
723 return _old_gen->block_start(addr);
724 }
725
726 bool SerialHeap::block_is_obj(const HeapWord* addr) const {
727 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
728 assert(block_start(addr) == addr, "addr must be a block start");
729
730 if (_young_gen->is_in_reserved(addr)) {
731 return _young_gen->eden()->is_in(addr)
732 || _young_gen->from()->is_in(addr)
733 || _young_gen->to() ->is_in(addr);
734 }
735
736 assert(_old_gen->is_in_reserved(addr), "must be in old-gen");
737 return addr < _old_gen->space()->top();
738 }
739
740 size_t SerialHeap::tlab_capacity(Thread* thr) const {
741 // Only young-gen supports tlab allocation.
742 return _young_gen->tlab_capacity();
743 }
744
745 size_t SerialHeap::tlab_used(Thread* thr) const {
746 return _young_gen->tlab_used();
747 }
748
749 size_t SerialHeap::unsafe_max_tlab_alloc(Thread* thr) const {
750 return _young_gen->unsafe_max_tlab_alloc();
751 }
752
753 HeapWord* SerialHeap::allocate_new_tlab(size_t min_size,
754 size_t requested_size,
755 size_t* actual_size) {
756 HeapWord* result = mem_allocate_work(requested_size /* size */,
757 true /* is_tlab */);
758 if (result != nullptr) {
759 *actual_size = requested_size;
760 }
761
762 return result;
763 }
764
765 void SerialHeap::prepare_for_verify() {
766 ensure_parsability(false); // no need to retire TLABs
767 }
768
769 void SerialHeap::save_marks() {
770 _young_gen_saved_top = _young_gen->to()->top();
771 _old_gen_saved_top = _old_gen->space()->top();
772 }
773
774 void SerialHeap::verify(VerifyOption option /* ignored */) {
775 log_debug(gc, verify)("%s", _old_gen->name());
776 _old_gen->verify();
777
778 log_debug(gc, verify)("%s", _young_gen->name());
779 _young_gen->verify();
780
781 log_debug(gc, verify)("RemSet");
782 rem_set()->verify();
783 }
784
785 void SerialHeap::print_heap_on(outputStream* st) const {
786 assert(_young_gen != nullptr, "precondition");
787 assert(_old_gen != nullptr, "precondition");
788
789 _young_gen->print_on(st);
790 _old_gen->print_on(st);
791 }
792
793 void SerialHeap::print_gc_on(outputStream* st) const {
794 BarrierSet* bs = BarrierSet::barrier_set();
795 if (bs != nullptr) {
796 bs->print_on(st);
797 }
798 }
799
800 void SerialHeap::gc_threads_do(ThreadClosure* tc) const {
801 }
802
803 bool SerialHeap::print_location(outputStream* st, void* addr) const {
804 return BlockLocationPrinter<SerialHeap>::print_location(st, addr);
805 }
806
807 void SerialHeap::print_tracing_info() const {
808 // Does nothing
809 }
810
811 void SerialHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const {
812 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
813
814 log_info(gc, heap)(HEAP_CHANGE_FORMAT" "
815 HEAP_CHANGE_FORMAT" "
816 HEAP_CHANGE_FORMAT,
817 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->name(),
818 pre_gc_values.young_gen_used(),
819 pre_gc_values.young_gen_capacity(),
820 def_new_gen->used(),
821 def_new_gen->capacity()),
822 HEAP_CHANGE_FORMAT_ARGS("Eden",
823 pre_gc_values.eden_used(),
824 pre_gc_values.eden_capacity(),
825 def_new_gen->eden()->used(),
826 def_new_gen->eden()->capacity()),
827 HEAP_CHANGE_FORMAT_ARGS("From",
828 pre_gc_values.from_used(),
829 pre_gc_values.from_capacity(),
830 def_new_gen->from()->used(),
831 def_new_gen->from()->capacity()));
832 log_info(gc, heap)(HEAP_CHANGE_FORMAT,
833 HEAP_CHANGE_FORMAT_ARGS(old_gen()->name(),
834 pre_gc_values.old_gen_used(),
835 pre_gc_values.old_gen_capacity(),
836 old_gen()->used(),
837 old_gen()->capacity()));
838 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes());
839 }
840
841 void SerialHeap::gc_prologue() {
842 // Fill TLAB's and such
843 ensure_parsability(true); // retire TLABs
844
845 _old_gen->gc_prologue();
846 };
847
848 void SerialHeap::gc_epilogue(bool full) {
849 #if COMPILER2_OR_JVMCI
850 assert(DerivedPointerTable::is_empty(), "derived pointer present");
851 #endif // COMPILER2_OR_JVMCI
852
853 resize_all_tlabs();
854
855 _young_gen->gc_epilogue(full);
856 _old_gen->gc_epilogue();
857
858 if (_is_heap_almost_full) {
859 // Reset the emergency state if eden is empty after a young/full gc
860 if (_young_gen->eden()->is_empty()) {
861 _is_heap_almost_full = false;
862 }
863 } else {
864 if (full && !_young_gen->eden()->is_empty()) {
865 // Usually eden should be empty after a full GC, so heap is probably too
866 // full now; entering emergency state.
867 _is_heap_almost_full = true;
868 }
869 }
870
871 MetaspaceCounters::update_performance_counters();
872 };