1 /*
2 * Copyright (c) 2014, 2026, 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 "gc/g1/g1Allocator.inline.hpp"
26 #include "gc/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1CollectionSet.hpp"
28 #include "gc/g1/g1EvacFailureRegions.inline.hpp"
29 #include "gc/g1/g1HeapRegionPrinter.hpp"
30 #include "gc/g1/g1OopClosures.inline.hpp"
31 #include "gc/g1/g1ParScanThreadState.inline.hpp"
32 #include "gc/g1/g1RootClosures.hpp"
33 #include "gc/g1/g1StringDedup.hpp"
34 #include "gc/g1/g1Trace.hpp"
35 #include "gc/g1/g1YoungGCAllocationFailureInjector.inline.hpp"
36 #include "gc/shared/continuationGCSupport.inline.hpp"
37 #include "gc/shared/partialArraySplitter.inline.hpp"
38 #include "gc/shared/partialArrayState.hpp"
39 #include "gc/shared/partialArrayTaskStats.hpp"
40 #include "gc/shared/stringdedup/stringDedup.hpp"
41 #include "gc/shared/taskqueue.inline.hpp"
42 #include "memory/allocation.inline.hpp"
43 #include "oops/access.inline.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "runtime/prefetch.inline.hpp"
47 #include "utilities/globalDefinitions.hpp"
48 #include "utilities/macros.hpp"
49
50 // In fastdebug builds the code size can get out of hand, potentially
51 // tripping over compiler limits (which may be bugs, but nevertheless
52 // need to be taken into consideration). A side benefit of limiting
53 // inlining is that we get more call frames that might aid debugging.
54 // And the fastdebug compile time for this file is much reduced.
55 // Explicit NOINLINE to block ATTRIBUTE_FLATTENing.
56 #define MAYBE_INLINE_EVACUATION NOT_DEBUG(inline) DEBUG_ONLY(NOINLINE)
57
58 // Good estimate for the initial table size.
59 static uint initial_nmethod_table_size(G1CollectedHeap* g1h) {
60 // The +1 is both to consider the retained old region likely to be added, and avoid zero-sized initial tables.
61 return MIN3(g1h->collection_set()->num_regions(), g1h->max_num_regions() / 2, g1h->num_available_regions()) + 1;
62 }
63
64 G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h,
65 G1ParScanThreadStateSet* per_thread_states,
66 uint worker_id,
67 uint num_workers,
68 G1CollectionSet* collection_set,
69 G1EvacFailureRegions* evac_failure_regions)
70 : _g1h(g1h),
71 _per_thread_states(per_thread_states),
72 _task_queue(g1h->task_queue(worker_id)),
73 _ct(g1h->refinement_table()),
74 _closures(nullptr),
75 _plab_allocator(nullptr),
76 _age_table(false),
77 _tenuring_threshold(g1h->policy()->tenuring_threshold()),
78 _scanner(g1h, this),
79 _worker_id(worker_id),
80 _num_cards_marked_dirty(0),
81 _num_cards_marked_to_cset(0),
82 _stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1),
83 _stack_trim_lower_threshold(GCDrainStackTargetSize),
84 _trim_ticks(),
85 _surviving_young_words_base(nullptr),
86 _surviving_young_words(nullptr),
87 _surviving_words_length(collection_set->num_young_regions() + 1),
88 _old_gen_is_full(false),
89 _partial_array_splitter(g1h->partial_array_state_manager(), num_workers),
90 _string_dedup_requests(),
91 _max_num_optional_regions(collection_set->num_optional_regions()),
92 _numa(g1h->numa()),
93 _obj_alloc_stat(nullptr),
94 // The initial size estimate is relatively conservative, assuming that all regions
95 // in the collection set get evacuated into the same amount of new regions.
96 _nmethods_to_add(initial_nmethod_table_size(g1h),
97 MAX2(initial_nmethod_table_size(g1h), _g1h->max_num_regions() / 2)),
98 ALLOCATION_FAILURE_INJECTOR_ONLY(_allocation_failure_inject_counter(0) COMMA)
99 _evacuation_failed_info(),
100 _evac_failure_regions(evac_failure_regions),
101 _num_cards_from_evac_failure(0)
102 {
103 // We allocate number of young gen regions in the collection set plus one
104 // entries, since entry 0 keeps track of surviving bytes for non-young regions.
105 // We also add a few elements at the beginning and at the end in
106 // an attempt to eliminate cache contention
107 const size_t padding_elem_num = (DEFAULT_PADDING_SIZE / sizeof(size_t));
108 size_t array_length = padding_elem_num + _surviving_words_length + padding_elem_num;
109
110 _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC);
111 _surviving_young_words = _surviving_young_words_base + padding_elem_num;
112 memset(_surviving_young_words, 0, _surviving_words_length * sizeof(size_t));
113
114 _plab_allocator = new G1PLABAllocator(_g1h->allocator());
115
116 _closures = G1EvacuationRootClosures::create_root_closures(_g1h,
117 this,
118 collection_set->only_contains_young_regions());
119
120 _oops_into_optional_regions = new G1OopStarChunkedList[_max_num_optional_regions];
121
122 initialize_numa_stats();
123 }
124
125 size_t G1ParScanThreadState::flush_stats(size_t* surviving_young_words, uint num_workers) {
126 flush_numa_stats();
127 // Update allocation statistics.
128 _plab_allocator->flush_and_retire_stats(num_workers);
129 _g1h->policy()->record_age_table(&_age_table);
130
131 if (_evacuation_failed_info.has_failed()) {
132 _g1h->gc_tracer_stw()->report_evacuation_failed(_evacuation_failed_info);
133 }
134
135 size_t sum = 0;
136 for (uint i = 0; i < _surviving_words_length; i++) {
137 surviving_young_words[i] += _surviving_young_words[i];
138 sum += _surviving_young_words[i];
139 }
140 return sum;
141 }
142
143 G1ParScanThreadState::~G1ParScanThreadState() {
144 auto delete_all = [&] (uint region, G1NmethodSet* nmethods) -> bool {
145 delete nmethods;
146 return true;
147 };
148 _nmethods_to_add.iterate(delete_all);
149
150 delete _plab_allocator;
151 delete _closures;
152 FREE_C_HEAP_ARRAY(_surviving_young_words_base);
153 delete[] _oops_into_optional_regions;
154 FREE_C_HEAP_ARRAY(_obj_alloc_stat);
155 }
156
157 size_t G1ParScanThreadState::lab_waste_words() const {
158 return _plab_allocator->waste();
159 }
160
161 size_t G1ParScanThreadState::lab_undo_waste_words() const {
162 return _plab_allocator->undo_waste();
163 }
164
165 size_t G1ParScanThreadState::num_cards_pending() const {
166 return _num_cards_marked_dirty + _num_cards_from_evac_failure;
167 }
168
169 size_t G1ParScanThreadState::num_cards_marked() const {
170 return num_cards_pending() + _num_cards_marked_to_cset;
171 }
172
173 size_t G1ParScanThreadState::num_cards_from_evac_failure() const {
174 return _num_cards_from_evac_failure;
175 }
176
177 #ifdef ASSERT
178 void G1ParScanThreadState::verify_task(narrowOop* task) const {
179 assert(task != nullptr, "invariant");
180 assert(UseCompressedOops, "sanity");
181 oop p = RawAccess<>::oop_load(task);
182 assert(_g1h->is_in_reserved(p),
183 "task=" PTR_FORMAT " p=" PTR_FORMAT, p2i(task), p2i(p));
184 }
185
186 void G1ParScanThreadState::verify_task(oop* task) const {
187 assert(task != nullptr, "invariant");
188 oop p = RawAccess<>::oop_load(task);
189 assert(_g1h->is_in_reserved(p),
190 "task=" PTR_FORMAT " p=" PTR_FORMAT, p2i(task), p2i(p));
191 }
192
193 void G1ParScanThreadState::verify_task(PartialArrayState* task) const {
194 assert(task != nullptr, "invariant");
195 // Source isn't used for processing, so not recorded in task.
196 assert(task->source() == nullptr, "invariant");
197 oop p = task->destination();
198 assert(_g1h->is_in_reserved(p),
199 "task=" PTR_FORMAT " dest=" PTR_FORMAT, p2i(task), p2i(p));
200 }
201
202 void G1ParScanThreadState::verify_task(ScannerTask task) const {
203 if (task.is_narrow_oop_ptr()) {
204 verify_task(task.to_narrow_oop_ptr());
205 } else if (task.is_oop_ptr()) {
206 verify_task(task.to_oop_ptr());
207 } else if (task.is_partial_array_state()) {
208 verify_task(task.to_partial_array_state());
209 } else {
210 ShouldNotReachHere();
211 }
212 }
213 #endif // ASSERT
214
215 template <class T>
216 MAYBE_INLINE_EVACUATION
217 void G1ParScanThreadState::do_oop_evac(T* p) {
218 // Reference should not be null here as such are never pushed to the task queue.
219 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
220
221 // Although we never intentionally push references outside of the collection
222 // set, due to (benign) races in the claim mechanism during RSet scanning more
223 // than one thread might claim the same card. So the same card may be
224 // processed multiple times, and so we might get references into old gen here.
225 // So we need to redo this check.
226 const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
227 // References pushed onto the work stack should never point to a humongous region
228 // as they are not added to the collection set due to above precondition.
229 assert(!region_attr.is_humongous_candidate(),
230 "Obj " PTR_FORMAT " should not refer to humongous region %u from " PTR_FORMAT,
231 p2i(obj), _g1h->addr_to_region(obj), p2i(p));
232
233 if (!region_attr.is_in_cset()) {
234 // In this case somebody else already did all the work.
235 return;
236 }
237
238 markWord m = obj->mark();
239 if (m.is_forwarded()) {
240 obj = obj->forwardee(m);
241 } else {
242 obj = do_copy_to_survivor_space(region_attr, obj, m);
243 }
244 RawAccess<IS_NOT_NULL>::oop_store(p, obj);
245
246 write_ref_field_post(p, obj);
247 }
248
249 MAYBE_INLINE_EVACUATION
250 void G1ParScanThreadState::do_partial_array(PartialArrayState* state, bool stolen) {
251 // Access state before release by claim().
252 objArrayOop to_array = objArrayOop(state->destination());
253 PartialArraySplitter::Claim claim =
254 _partial_array_splitter.claim(state, _task_queue, stolen);
255 G1HeapRegionAttr dest_attr = _g1h->region_attr(to_array);
256 G1SkipCardMarkSetter x(&_scanner, dest_attr.is_new_survivor());
257 // Process claimed task.
258 to_array->oop_iterate_elements_range(&_scanner,
259 checked_cast<int>(claim._start),
260 checked_cast<int>(claim._end));
261 }
262
263 MAYBE_INLINE_EVACUATION
264 void G1ParScanThreadState::start_partial_objarray(oop from_obj,
265 oop to_obj) {
266 assert(from_obj->is_forwarded(), "precondition");
267 assert(from_obj->forwardee() == to_obj, "precondition");
268 assert(to_obj->is_objArray(), "precondition");
269
270 objArrayOop to_array = objArrayOop(to_obj);
271 size_t array_length = to_array->length();
272 size_t initial_chunk_size =
273 // The source array is unused when processing states.
274 _partial_array_splitter.start(_task_queue, nullptr, to_array, array_length, ParGCArrayScanChunk);
275
276 assert(_scanner.skip_card_mark_set(), "must be");
277 // Process the initial chunk. No need to process the type in the
278 // klass, as it will already be handled by processing the built-in
279 // module.
280 to_array->oop_iterate_elements_range(&_scanner, 0, checked_cast<int>(initial_chunk_size));
281 }
282
283 MAYBE_INLINE_EVACUATION
284 void G1ParScanThreadState::dispatch_task(ScannerTask task, bool stolen) {
285 verify_task(task);
286 if (task.is_narrow_oop_ptr()) {
287 do_oop_evac(task.to_narrow_oop_ptr());
288 } else if (task.is_oop_ptr()) {
289 do_oop_evac(task.to_oop_ptr());
290 } else {
291 do_partial_array(task.to_partial_array_state(), stolen);
292 }
293 }
294
295 // Process tasks until overflow queue is empty and local queue
296 // contains no more than threshold entries. NOINLINE to prevent
297 // inlining into steal_and_trim_queue.
298 ATTRIBUTE_FLATTEN NOINLINE
299 void G1ParScanThreadState::trim_queue_to_threshold(uint threshold) {
300 ScannerTask task;
301 do {
302 while (_task_queue->pop_overflow(task)) {
303 if (!_task_queue->try_push_to_taskqueue(task)) {
304 dispatch_task(task, false);
305 }
306 }
307 while (_task_queue->pop_local(task, threshold)) {
308 dispatch_task(task, false);
309 }
310 } while (!_task_queue->overflow_empty());
311 }
312
313 ATTRIBUTE_FLATTEN
314 void G1ParScanThreadState::steal_and_trim_queue(G1ScannerTasksQueueSet* task_queues) {
315 ScannerTask stolen_task;
316 while (task_queues->steal(_worker_id, stolen_task)) {
317 dispatch_task(stolen_task, true);
318 // Processing stolen task may have added tasks to our queue.
319 trim_queue();
320 }
321 }
322
323 HeapWord* G1ParScanThreadState::allocate_in_next_plab(G1HeapRegionAttr* dest,
324 size_t word_sz,
325 bool previous_plab_refill_failed,
326 uint node_index) {
327
328 assert(dest->is_in_cset_or_humongous_candidate(), "Unexpected dest: %s region attr", dest->get_type_str());
329
330 // Right now we only have two types of regions (young / old) so
331 // let's keep the logic here simple. We can generalize it when necessary.
332 if (dest->is_young()) {
333 bool plab_refill_in_old_failed = false;
334 HeapWord* const obj_ptr = _plab_allocator->allocate(G1HeapRegionAttr::Old,
335 word_sz,
336 &plab_refill_in_old_failed,
337 node_index);
338 // Make sure that we won't attempt to copy any other objects out
339 // of a survivor region (given that apparently we cannot allocate
340 // any new ones) to avoid coming into this slow path again and again.
341 // Only consider failed PLAB refill here: failed inline allocations are
342 // typically large, so not indicative of remaining space.
343 if (previous_plab_refill_failed) {
344 _tenuring_threshold = 0;
345 }
346
347 if (obj_ptr != nullptr) {
348 dest->set_old();
349 } else {
350 // We just failed to allocate in old gen. The same idea as explained above
351 // for making survivor gen unavailable for allocation applies for old gen.
352 _old_gen_is_full = plab_refill_in_old_failed;
353 }
354 return obj_ptr;
355 } else {
356 _old_gen_is_full = previous_plab_refill_failed;
357 assert(dest->is_old(), "Unexpected dest region attr: %s", dest->get_type_str());
358 // no other space to try.
359 return nullptr;
360 }
361 }
362
363 G1HeapRegionAttr G1ParScanThreadState::next_region_attr(G1HeapRegionAttr const region_attr, markWord const m, uint& age) {
364 assert(region_attr.is_young() || region_attr.is_old(), "must be either Young or Old");
365
366 if (region_attr.is_young()) {
367 age = !m.has_displaced_mark_helper() ? m.age()
368 : m.displaced_mark_helper().age();
369 if (age < _tenuring_threshold) {
370 return region_attr;
371 }
372 }
373 // young-to-old (promotion) or old-to-old; destination is old in both cases.
374 return G1HeapRegionAttr::Old;
375 }
376
377 void G1ParScanThreadState::report_promotion_event(G1HeapRegionAttr const dest_attr,
378 Klass* klass, size_t word_sz, uint age,
379 HeapWord * const obj_ptr, uint node_index) const {
380 PLAB* alloc_buf = _plab_allocator->alloc_buffer(dest_attr, node_index);
381 if (alloc_buf->contains(obj_ptr)) {
382 _g1h->gc_tracer_stw()->report_promotion_in_new_plab_event(klass, word_sz * HeapWordSize, age,
383 dest_attr.type() == G1HeapRegionAttr::Old,
384 alloc_buf->word_sz() * HeapWordSize);
385 } else {
386 _g1h->gc_tracer_stw()->report_promotion_outside_plab_event(klass, word_sz * HeapWordSize, age,
387 dest_attr.type() == G1HeapRegionAttr::Old);
388 }
389 }
390
391 NOINLINE
392 HeapWord* G1ParScanThreadState::allocate_copy_slow(G1HeapRegionAttr* dest_attr,
393 Klass* klass,
394 size_t word_sz,
395 uint age,
396 uint node_index) {
397 HeapWord* obj_ptr = nullptr;
398 // Try slow-path allocation unless we're allocating old and old is already full.
399 if (!(dest_attr->is_old() && _old_gen_is_full)) {
400 bool plab_refill_failed = false;
401 obj_ptr = _plab_allocator->allocate_direct_or_new_plab(*dest_attr,
402 word_sz,
403 &plab_refill_failed,
404 node_index);
405 if (obj_ptr == nullptr) {
406 obj_ptr = allocate_in_next_plab(dest_attr,
407 word_sz,
408 plab_refill_failed,
409 node_index);
410 }
411 }
412 if (obj_ptr != nullptr) {
413 update_numa_stats(node_index);
414 if (_g1h->gc_tracer_stw()->should_report_promotion_events()) {
415 // The events are checked individually as part of the actual commit
416 report_promotion_event(*dest_attr, klass, word_sz, age, obj_ptr, node_index);
417 }
418 }
419 return obj_ptr;
420 }
421
422 #if ALLOCATION_FAILURE_INJECTOR
423 bool G1ParScanThreadState::inject_allocation_failure(uint region_idx) {
424 return _g1h->allocation_failure_injector()->allocation_should_fail(_allocation_failure_inject_counter, region_idx);
425 }
426 #endif
427
428 NOINLINE
429 void G1ParScanThreadState::undo_allocation(G1HeapRegionAttr dest_attr,
430 HeapWord* obj_ptr,
431 size_t word_sz,
432 uint node_index) {
433 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
434 }
435
436 void G1ParScanThreadState::update_bot_after_copying(oop obj, size_t word_sz) {
437 HeapWord* obj_start = cast_from_oop<HeapWord*>(obj);
438 G1HeapRegion* region = _g1h->heap_region_containing(obj_start);
439 region->update_bot_for_block(obj_start, obj_start + word_sz);
440 }
441
442 ALWAYSINLINE
443 void G1ParScanThreadState::do_iterate_object(oop const obj,
444 oop const old,
445 Klass* const klass,
446 G1HeapRegionAttr const region_attr,
447 G1HeapRegionAttr const dest_attr,
448 uint age) {
449 // Most objects are not arrays, so do one array check rather than
450 // checking for each array category for each object.
451 if (klass->is_array_klass()) {
452 assert(!klass->is_stack_chunk_instance_klass(), "must be");
453
454 if (klass->is_objArray_klass()) {
455 start_partial_objarray(old, obj);
456 } else {
457 // Nothing needs to be done for typeArrays. Body doesn't contain
458 // any oops to scan, and the type in the klass will already be handled
459 // by processing the built-in module.
460 assert(klass->is_typeArray_klass(), "invariant");
461 }
462 return;
463 }
464
465 ContinuationGCSupport::transform_stack_chunk(obj, klass);
466
467 // Check for deduplicating young Strings.
468 if (G1StringDedup::is_candidate_from_evacuation(klass,
469 region_attr,
470 dest_attr,
471 age)) {
472 // Record old; request adds a new weak reference, which reference
473 // processing expects to refer to a from-space object.
474 _string_dedup_requests.add(old);
475 }
476
477 assert(_scanner.skip_card_mark_set(), "must be");
478 obj->oop_iterate_backwards(&_scanner, klass);
479 }
480
481 // Private inline function, for direct internal use and providing the
482 // implementation of the public not-inline function.
483 MAYBE_INLINE_EVACUATION
484 oop G1ParScanThreadState::do_copy_to_survivor_space(G1HeapRegionAttr const region_attr,
485 oop const old,
486 markWord const old_mark) {
487 assert(region_attr.is_in_cset(),
488 "Unexpected region attr type: %s", region_attr.get_type_str());
489
490 // NOTE: With compact headers, it is not safe to load the Klass* from old, because
491 // that would access the mark-word, that might change at any time by concurrent
492 // workers.
493 // This mark word would refer to a forwardee, which may not yet have completed
494 // copying. Therefore we must load the Klass* from the mark-word that we already
495 // loaded. This is safe, because we only enter here if not yet forwarded.
496 assert(!old_mark.is_forwarded(), "precondition");
497 Klass* klass = UseCompactObjectHeaders
498 ? old_mark.klass()
499 : old->klass();
500
501 const size_t word_sz = old->size_given_klass(klass);
502
503 // JNI only allows pinning of typeArrays, so we only need to keep those in place.
504 if (region_attr.is_pinned() && klass->is_typeArray_klass()) {
505 return handle_evacuation_failure_par(old, old_mark, klass, region_attr, word_sz, true /* cause_pinned */);
506 }
507
508 uint age = 0;
509 G1HeapRegionAttr dest_attr = next_region_attr(region_attr, old_mark, age);
510 G1HeapRegion* const from_region = _g1h->heap_region_containing(old);
511 uint node_index = from_region->node_index();
512
513 HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_attr, word_sz, node_index);
514
515 // PLAB allocations should succeed most of the time, so we'll
516 // normally check against null once and that's it.
517 if (obj_ptr == nullptr) {
518 obj_ptr = allocate_copy_slow(&dest_attr, klass, word_sz, age, node_index);
519 if (obj_ptr == nullptr) {
520 // This will either forward-to-self, or detect that someone else has
521 // installed a forwarding pointer.
522 return handle_evacuation_failure_par(old, old_mark, klass, region_attr, word_sz, false /* cause_pinned */);
523 }
524 }
525
526 assert(obj_ptr != nullptr, "when we get here, allocation should have succeeded");
527 assert(_g1h->is_in_reserved(obj_ptr), "Allocated memory should be in the heap");
528
529 // Should this evacuation fail?
530 if (inject_allocation_failure(from_region->hrm_index())) {
531 // Doing this after all the allocation attempts also tests the
532 // undo_allocation() method too.
533 undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
534 return handle_evacuation_failure_par(old, old_mark, klass, region_attr, word_sz, false /* cause_pinned */);
535 }
536
537 // We're going to allocate linearly, so might as well prefetch ahead.
538 Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);
539 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(old), obj_ptr, word_sz);
540
541 const oop obj = cast_to_oop(obj_ptr);
542 // Because the forwarding is done with memory_order_relaxed there is no
543 // ordering with the above copy. Clients that get the forwardee must not
544 // examine its contents without other synchronization, since the contents
545 // may not be up to date for them.
546 const oop forward_ptr = old->forward_to_atomic(obj, old_mark, memory_order_relaxed);
547 if (forward_ptr == nullptr) {
548
549 {
550 const uint young_index = from_region->young_index_in_cset();
551 assert((from_region->is_young() && young_index > 0) ||
552 (!from_region->is_young() && young_index == 0), "invariant" );
553 _surviving_young_words[young_index] += word_sz;
554 }
555
556 if (dest_attr.is_young()) {
557 if (age < markWord::max_age) {
558 age++;
559 obj->incr_age();
560 }
561 _age_table.add(age, word_sz);
562 } else {
563 update_bot_after_copying(obj, word_sz);
564 }
565
566 {
567 // Skip the card enqueue iff the object (obj) is in survivor region.
568 // However, G1HeapRegion::is_survivor() is too expensive here.
569 // Instead, we use dest_attr.is_young() because the two values are always
570 // equal: successfully allocated young regions must be survivor regions.
571 assert(dest_attr.is_young() == _g1h->heap_region_containing(obj)->is_survivor(), "must be");
572 G1SkipCardMarkSetter x(&_scanner, dest_attr.is_young());
573 do_iterate_object(obj, old, klass, region_attr, dest_attr, age);
574 }
575
576 return obj;
577 } else {
578 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
579 return forward_ptr;
580 }
581 }
582
583 // Public not-inline entry point.
584 ATTRIBUTE_FLATTEN
585 oop G1ParScanThreadState::copy_to_survivor_space(G1HeapRegionAttr region_attr,
586 oop old,
587 markWord old_mark) {
588 return do_copy_to_survivor_space(region_attr, old, old_mark);
589 }
590
591 G1ParScanThreadState* G1ParScanThreadStateSet::state_for_worker(uint worker_id) {
592 assert(worker_id < _num_workers, "out of bounds access");
593 if (_states[worker_id] == nullptr) {
594 _states[worker_id] =
595 new G1ParScanThreadState(_g1h,
596 this,
597 worker_id,
598 _num_workers,
599 _collection_set,
600 _evac_failure_regions);
601 }
602 return _states[worker_id];
603 }
604
605 const size_t* G1ParScanThreadStateSet::surviving_young_words() const {
606 assert(_flushed, "thread local state from the per thread states should have been flushed");
607 return _surviving_young_words_total;
608 }
609
610 void G1ParScanThreadStateSet::flush_stats() {
611 assert(!_flushed, "thread local state from the per thread states should be flushed once");
612 for (uint worker_id = 0; worker_id < _num_workers; ++worker_id) {
613 G1ParScanThreadState* pss = _states[worker_id];
614 assert(pss != nullptr, "must be initialized");
615
616 G1GCPhaseTimes* p = _g1h->phase_times();
617
618 // Need to get the following two before the call to G1ParThreadScanState::flush()
619 // because it resets the PLAB allocator where we get this info from.
620 size_t lab_waste_bytes = pss->lab_waste_words() * HeapWordSize;
621 size_t lab_undo_waste_bytes = pss->lab_undo_waste_words() * HeapWordSize;
622 size_t copied_bytes = pss->flush_stats(_surviving_young_words_total, _num_workers) * HeapWordSize;
623 size_t pending_cards = pss->num_cards_pending();
624 size_t to_young_gen_cards = pss->num_cards_marked() - pss->num_cards_pending();
625 size_t evac_failure_cards = pss->num_cards_from_evac_failure();
626 size_t marked_cards = pss->num_cards_marked();
627
628 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, copied_bytes, G1GCPhaseTimes::FlushPSSCopiedBytes);
629 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, lab_waste_bytes, G1GCPhaseTimes::FlushPSSLABWasteBytes);
630 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, lab_undo_waste_bytes, G1GCPhaseTimes::FlushPSSLABUndoWasteBytes);
631 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, pending_cards, G1GCPhaseTimes::FlushPSSPendingCards);
632 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, to_young_gen_cards, G1GCPhaseTimes::FlushPSSToYoungGenCards);
633 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, evac_failure_cards, G1GCPhaseTimes::FlushPSSEvacFail);
634 p->record_or_add_thread_work_item(G1GCPhaseTimes::FlushPSS, worker_id, marked_cards, G1GCPhaseTimes::FlushPSSMarked);
635 }
636
637 _flushed = true;
638 }
639
640 void G1ParScanThreadStateSet::destroy_worker_states() {
641 assert(_flushed, "statistics must already be flushed");
642 for (uint worker_id = 0; worker_id < _num_workers; ++worker_id) {
643 delete _states[worker_id];
644 _states[worker_id] = nullptr;
645 }
646 }
647
648 void G1ParScanThreadStateSet::update_nmethod_regions_to_add(G1NmethodsToAdd* nmethods) {
649 if (nmethods->number_of_entries() == 0) {
650 return;
651 }
652
653 // Take the key set, look which are not yet in the global set, and update the necessary ones.
654 ResourceMark rm;
655 GrowableArray<uint> regions_to_add = GrowableArray<uint>(nmethods->table_size());
656
657 nmethods->iterate_all([&] (uint& region, void*) {
658 if (_has_nmethods_to_add.par_set_bit(region, memory_order_relaxed)) {
659 regions_to_add.push(region);
660 }
661 });
662
663 uint num_regions_to_add = (uint)regions_to_add.length();
664
665 if (num_regions_to_add == 0) {
666 return;
667 }
668
669 uint first_index = _num_nmethod_regions_to_add.fetch_then_add(num_regions_to_add, memory_order_relaxed);
670 guarantee(first_index + num_regions_to_add <= _g1h->max_num_regions(), "must be");
671
672 memcpy(&_nmethod_regions_to_add[first_index], regions_to_add.adr_at(0), num_regions_to_add * sizeof(uint));
673 }
674
675 void G1ParScanThreadStateSet::par_iterate_nmethod_regions_to_add(G1HeapRegionClosure* cl,
676 G1HeapRegionClaimer* claimer,
677 uint worker_id) {
678 _g1h->par_iterate_regions_array(cl, claimer, _nmethod_regions_to_add, num_nmethod_regions_to_add(), worker_id);
679 }
680
681 void G1ParScanThreadStateSet::record_unused_optional_region(G1HeapRegion* hr) {
682 for (uint worker_index = 0; worker_index < _num_workers; ++worker_index) {
683 G1ParScanThreadState* pss = _states[worker_index];
684 assert(pss != nullptr, "must be initialized");
685
686 size_t used_memory = pss->oops_into_optional_region(hr)->used_memory();
687 _g1h->phase_times()->record_or_add_thread_work_item(G1GCPhaseTimes::OptScanHR, worker_index, used_memory, G1GCPhaseTimes::ScanHRUsedMemory);
688 }
689 }
690
691 void G1ParScanThreadState::record_evacuation_failed_region(G1HeapRegion* r, uint worker_id, bool cause_pinned) {
692 if (_evac_failure_regions->record(worker_id, r->hrm_index(), cause_pinned)) {
693 G1HeapRegionPrinter::evac_failure(r);
694 }
695 }
696
697 NOINLINE
698 oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markWord m, Klass* klass, G1HeapRegionAttr attr, size_t word_sz, bool cause_pinned) {
699 assert(_g1h->is_in_cset(old), "Object " PTR_FORMAT " should be in the CSet", p2i(old));
700
701 oop forward_ptr = old->forward_to_self_atomic(m, memory_order_relaxed);
702 if (forward_ptr == nullptr) {
703 // Forward-to-self succeeded. We are the "owner" of the object.
704 G1HeapRegion* r = _g1h->heap_region_containing(old);
705
706 record_evacuation_failed_region(r, _worker_id, cause_pinned);
707
708 // Mark the failing object in the marking bitmap and later use the bitmap to handle
709 // evacuation failure recovery.
710 _g1h->mark_evac_failure_object(old);
711
712 _evacuation_failed_info.register_copy_failure(word_sz);
713
714 {
715 // For iterating objects that failed evacuation currently we can reuse the
716 // existing closure to scan evacuated objects; since we are iterating from a
717 // collection set region (i.e. never a Survivor region), we always need to
718 // gather cards for this case.
719 G1SkipCardMarkSetter x(&_scanner, false /* skip_card_mark */);
720 do_iterate_object(old, old, klass, attr, attr, m.age());
721 }
722
723 return old;
724 } else {
725 // Forward-to-self failed. Either someone else managed to allocate
726 // space for this object (old != forward_ptr) or they beat us in
727 // self-forwarding it (old == forward_ptr).
728 assert(old == forward_ptr || !_g1h->is_in_cset(forward_ptr),
729 "Object " PTR_FORMAT " forwarded to: " PTR_FORMAT " "
730 "should not be in the CSet",
731 p2i(old), p2i(forward_ptr));
732 return forward_ptr;
733 }
734 }
735
736 void G1ParScanThreadState::update_nmethod_regions_to_add() {
737 _per_thread_states->update_nmethod_regions_to_add(&_nmethods_to_add);
738 }
739
740 void G1ParScanThreadState::initialize_numa_stats() {
741 if (_numa->is_enabled()) {
742 LogTarget(Info, gc, heap, numa) lt;
743
744 if (lt.is_enabled()) {
745 uint num_nodes = _numa->num_active_nodes();
746 // Record only if there are multiple active nodes.
747 _obj_alloc_stat = NEW_C_HEAP_ARRAY(size_t, num_nodes, mtGC);
748 memset(_obj_alloc_stat, 0, sizeof(size_t) * num_nodes);
749 }
750 }
751 }
752
753 void G1ParScanThreadState::flush_numa_stats() {
754 if (_obj_alloc_stat != nullptr) {
755 uint node_index = _numa->index_of_current_thread();
756 _numa->copy_statistics(G1NUMAStats::LocalObjProcessAtCopyToSurv, node_index, _obj_alloc_stat);
757 }
758 }
759
760 void G1ParScanThreadState::update_numa_stats(uint node_index) {
761 if (_obj_alloc_stat != nullptr) {
762 _obj_alloc_stat[node_index]++;
763 }
764 }
765
766 #if TASKQUEUE_STATS
767
768 PartialArrayTaskStats* G1ParScanThreadState::partial_array_task_stats() {
769 return _partial_array_splitter.stats();
770 }
771
772 #endif // TASKQUEUE_STATS
773
774 G1ParScanThreadStateSet::G1ParScanThreadStateSet(G1CollectedHeap* g1h,
775 uint num_workers,
776 G1CollectionSet* collection_set,
777 G1EvacFailureRegions* evac_failure_regions) :
778 _g1h(g1h),
779 _collection_set(collection_set),
780 _states(NEW_C_HEAP_ARRAY(G1ParScanThreadState*, num_workers, mtGC)),
781 _surviving_young_words_total(NEW_C_HEAP_ARRAY(size_t, collection_set->num_young_regions() + 1, mtGC)),
782 _num_workers(num_workers),
783 _flushed(false),
784 _evac_failure_regions(evac_failure_regions),
785 _has_nmethods_to_add(g1h->max_num_regions(), mtGC),
786 _num_nmethod_regions_to_add(0),
787 _nmethod_regions_to_add(NEW_C_HEAP_ARRAY(uint, g1h->max_num_regions(), mtGC)) // Conservative length estimation.
788 {
789 for (uint i = 0; i < num_workers; ++i) {
790 _states[i] = nullptr;
791 }
792 memset(_surviving_young_words_total, 0, (collection_set->num_young_regions() + 1) * sizeof(size_t));
793 }
794
795 G1ParScanThreadStateSet::~G1ParScanThreadStateSet() {
796 for (uint i = 0; i < _num_workers; i++) {
797 assert(_states[i] == nullptr, "must be");
798 }
799 FREE_C_HEAP_ARRAY(_nmethod_regions_to_add);
800 FREE_C_HEAP_ARRAY(_states);
801 FREE_C_HEAP_ARRAY(_surviving_young_words_total);
802 }
803
804 #if TASKQUEUE_STATS
805
806 void G1ParScanThreadStateSet::print_partial_array_task_stats() {
807 auto get_stats = [&](uint i) {
808 return state_for_worker(i)->partial_array_task_stats();
809 };
810 PartialArrayTaskStats::log_set(_num_workers, get_stats,
811 "Young GC Partial Array");
812 }
813
814 #endif // TASKQUEUE_STATS