1 /*
2 * Copyright (c) 2014, 2022, 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 "precompiled.hpp"
26 #include "gc/g1/g1Allocator.inline.hpp"
27 #include "gc/g1/g1CollectedHeap.inline.hpp"
28 #include "gc/g1/g1CollectionSet.hpp"
29 #include "gc/g1/g1EvacFailureRegions.inline.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/g1YoungGCEvacFailureInjector.inline.hpp"
36 #include "gc/shared/continuationGCSupport.inline.hpp"
37 #include "gc/shared/partialArrayTaskStepper.inline.hpp"
38 #include "gc/shared/preservedMarks.inline.hpp"
39 #include "gc/shared/stringdedup/stringDedup.hpp"
40 #include "gc/shared/taskqueue.inline.hpp"
41 #include "memory/allocation.inline.hpp"
42 #include "oops/access.inline.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "runtime/atomic.hpp"
45 #include "runtime/prefetch.inline.hpp"
46 #include "utilities/globalDefinitions.hpp"
47 #include "utilities/macros.hpp"
48
49 // In fastdebug builds the code size can get out of hand, potentially
50 // tripping over compiler limits (which may be bugs, but nevertheless
51 // need to be taken into consideration). A side benefit of limiting
52 // inlining is that we get more call frames that might aid debugging.
53 // And the fastdebug compile time for this file is much reduced.
54 // Explicit NOINLINE to block ATTRIBUTE_FLATTENing.
55 #define MAYBE_INLINE_EVACUATION NOT_DEBUG(inline) DEBUG_ONLY(NOINLINE)
56
57 G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h,
58 G1RedirtyCardsQueueSet* rdcqs,
59 PreservedMarks* preserved_marks,
60 uint worker_id,
61 uint n_workers,
62 size_t young_cset_length,
63 size_t optional_cset_length,
64 G1EvacFailureRegions* evac_failure_regions)
65 : _g1h(g1h),
66 _task_queue(g1h->task_queue(worker_id)),
67 _rdc_local_qset(rdcqs),
68 _ct(g1h->card_table()),
69 _closures(NULL),
70 _plab_allocator(NULL),
71 _age_table(false),
72 _tenuring_threshold(g1h->policy()->tenuring_threshold()),
73 _scanner(g1h, this),
74 _worker_id(worker_id),
75 _last_enqueued_card(SIZE_MAX),
76 _stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1),
77 _stack_trim_lower_threshold(GCDrainStackTargetSize),
78 _trim_ticks(),
79 _surviving_young_words_base(NULL),
80 _surviving_young_words(NULL),
81 _surviving_words_length(young_cset_length + 1),
82 _old_gen_is_full(false),
83 _partial_objarray_chunk_size(ParGCArrayScanChunk),
84 _partial_array_stepper(n_workers),
85 _string_dedup_requests(),
86 _num_optional_regions(optional_cset_length),
87 _numa(g1h->numa()),
88 _obj_alloc_stat(NULL),
89 EVAC_FAILURE_INJECTOR_ONLY(_evac_failure_inject_counter(0) COMMA)
90 _preserved_marks(preserved_marks),
91 _evacuation_failed_info(),
92 _evac_failure_regions(evac_failure_regions)
93 {
94 // We allocate number of young gen regions in the collection set plus one
95 // entries, since entry 0 keeps track of surviving bytes for non-young regions.
96 // We also add a few elements at the beginning and at the end in
97 // an attempt to eliminate cache contention
98 const size_t padding_elem_num = (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t));
99 size_t array_length = padding_elem_num + _surviving_words_length + padding_elem_num;
100
101 _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC);
102 _surviving_young_words = _surviving_young_words_base + padding_elem_num;
103 memset(_surviving_young_words, 0, _surviving_words_length * sizeof(size_t));
104
105 _plab_allocator = new G1PLABAllocator(_g1h->allocator());
106
107 _closures = G1EvacuationRootClosures::create_root_closures(this, _g1h);
108
109 _oops_into_optional_regions = new G1OopStarChunkedList[_num_optional_regions];
110
111 initialize_numa_stats();
112 }
113
114 size_t G1ParScanThreadState::flush_stats(size_t* surviving_young_words, uint num_workers) {
115 _rdc_local_qset.flush();
116 flush_numa_stats();
117 // Update allocation statistics.
118 _plab_allocator->flush_and_retire_stats(num_workers);
119 _g1h->policy()->record_age_table(&_age_table);
120
121 if (_evacuation_failed_info.has_failed()) {
122 _g1h->gc_tracer_stw()->report_evacuation_failed(_evacuation_failed_info);
123 }
124
125 size_t sum = 0;
126 for (uint i = 0; i < _surviving_words_length; i++) {
127 surviving_young_words[i] += _surviving_young_words[i];
128 sum += _surviving_young_words[i];
129 }
130 return sum;
131 }
132
133 G1ParScanThreadState::~G1ParScanThreadState() {
134 delete _plab_allocator;
135 delete _closures;
136 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base);
137 delete[] _oops_into_optional_regions;
138 FREE_C_HEAP_ARRAY(size_t, _obj_alloc_stat);
139 }
140
141 size_t G1ParScanThreadState::lab_waste_words() const {
142 return _plab_allocator->waste();
143 }
144
145 size_t G1ParScanThreadState::lab_undo_waste_words() const {
146 return _plab_allocator->undo_waste();
147 }
148
149 #ifdef ASSERT
150 void G1ParScanThreadState::verify_task(narrowOop* task) const {
151 assert(task != NULL, "invariant");
152 assert(UseCompressedOops, "sanity");
153 oop p = RawAccess<>::oop_load(task);
154 assert(_g1h->is_in_reserved(p),
155 "task=" PTR_FORMAT " p=" PTR_FORMAT, p2i(task), p2i(p));
156 }
157
158 void G1ParScanThreadState::verify_task(oop* task) const {
159 assert(task != NULL, "invariant");
160 oop p = RawAccess<>::oop_load(task);
161 assert(_g1h->is_in_reserved(p),
162 "task=" PTR_FORMAT " p=" PTR_FORMAT, p2i(task), p2i(p));
163 }
164
165 void G1ParScanThreadState::verify_task(PartialArrayScanTask task) const {
166 // Must be in the collection set--it's already been copied.
167 oop p = task.to_source_array();
168 assert(_g1h->is_in_cset(p), "p=" PTR_FORMAT, p2i(p));
169 }
170
171 void G1ParScanThreadState::verify_task(ScannerTask task) const {
172 if (task.is_narrow_oop_ptr()) {
173 verify_task(task.to_narrow_oop_ptr());
174 } else if (task.is_oop_ptr()) {
175 verify_task(task.to_oop_ptr());
176 } else if (task.is_partial_array_task()) {
177 verify_task(task.to_partial_array_task());
178 } else {
179 ShouldNotReachHere();
180 }
181 }
182 #endif // ASSERT
183
184 template <class T>
185 MAYBE_INLINE_EVACUATION
186 void G1ParScanThreadState::do_oop_evac(T* p) {
187 // Reference should not be NULL here as such are never pushed to the task queue.
188 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
189
190 // Although we never intentionally push references outside of the collection
191 // set, due to (benign) races in the claim mechanism during RSet scanning more
192 // than one thread might claim the same card. So the same card may be
193 // processed multiple times, and so we might get references into old gen here.
194 // So we need to redo this check.
195 const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
196 // References pushed onto the work stack should never point to a humongous region
197 // as they are not added to the collection set due to above precondition.
198 assert(!region_attr.is_humongous_candidate(),
199 "Obj " PTR_FORMAT " should not refer to humongous region %u from " PTR_FORMAT,
200 p2i(obj), _g1h->addr_to_region(obj), p2i(p));
201
202 if (!region_attr.is_in_cset()) {
203 // In this case somebody else already did all the work.
204 return;
205 }
206
207 markWord m = obj->mark();
208 if (m.is_marked()) {
209 obj = obj->forwardee(m);
210 } else {
211 obj = do_copy_to_survivor_space(region_attr, obj, m);
212 }
213 RawAccess<IS_NOT_NULL>::oop_store(p, obj);
214
215 write_ref_field_post(p, obj);
216 }
217
218 MAYBE_INLINE_EVACUATION
219 void G1ParScanThreadState::do_partial_array(PartialArrayScanTask task) {
220 oop from_obj = task.to_source_array();
221
222 assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
223 assert(from_obj->is_forwarded(), "must be forwarded");
224
225 oop to_obj = from_obj->forwardee();
226 assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
227 assert(to_obj->is_objArray(), "must be obj array");
228 objArrayOop to_array = objArrayOop(to_obj);
229
230 PartialArrayTaskStepper::Step step
231 = _partial_array_stepper.next(objArrayOop(from_obj),
232 to_array,
233 _partial_objarray_chunk_size);
234 for (uint i = 0; i < step._ncreate; ++i) {
235 push_on_queue(ScannerTask(PartialArrayScanTask(from_obj)));
236 }
237
238 G1HeapRegionAttr dest_attr = _g1h->region_attr(to_array);
239 G1SkipCardEnqueueSetter x(&_scanner, dest_attr.is_new_survivor());
240 // Process claimed task. The length of to_array is not correct, but
241 // fortunately the iteration ignores the length field and just relies
242 // on start/end.
243 to_array->oop_iterate_range(&_scanner,
244 step._index,
245 step._index + _partial_objarray_chunk_size);
246 }
247
248 MAYBE_INLINE_EVACUATION
249 void G1ParScanThreadState::start_partial_objarray(G1HeapRegionAttr dest_attr,
250 oop from_obj,
251 oop to_obj) {
252 assert(from_obj->is_forwarded(), "precondition");
253 assert(from_obj->forwardee() == to_obj, "precondition");
254 assert(from_obj != to_obj, "should not be scanning self-forwarded objects");
255 assert(to_obj->is_objArray(), "precondition");
256
257 objArrayOop to_array = objArrayOop(to_obj);
258
259 PartialArrayTaskStepper::Step step
260 = _partial_array_stepper.start(objArrayOop(from_obj),
261 to_array,
262 _partial_objarray_chunk_size);
263
264 // Push any needed partial scan tasks. Pushed before processing the
265 // initial chunk to allow other workers to steal while we're processing.
266 for (uint i = 0; i < step._ncreate; ++i) {
267 push_on_queue(ScannerTask(PartialArrayScanTask(from_obj)));
268 }
269
270 // Skip the card enqueue iff the object (to_array) is in survivor region.
271 // However, HeapRegion::is_survivor() is too expensive here.
272 // Instead, we use dest_attr.is_young() because the two values are always
273 // equal: successfully allocated young regions must be survivor regions.
274 assert(dest_attr.is_young() == _g1h->heap_region_containing(to_array)->is_survivor(), "must be");
275 G1SkipCardEnqueueSetter x(&_scanner, dest_attr.is_young());
276 // Process the initial chunk. No need to process the type in the
277 // klass, as it will already be handled by processing the built-in
278 // module. The length of to_array is not correct, but fortunately
279 // the iteration ignores that length field and relies on start/end.
280 to_array->oop_iterate_range(&_scanner, 0, step._index);
281 }
282
283 MAYBE_INLINE_EVACUATION
284 void G1ParScanThreadState::dispatch_task(ScannerTask task) {
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_task());
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);
305 }
306 }
307 while (_task_queue->pop_local(task, threshold)) {
308 dispatch_task(task);
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);
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 != NULL) {
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 NULL;
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 oop const old, 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 oop old,
394 Klass* klass,
395 size_t word_sz,
396 uint age,
397 uint node_index) {
398 HeapWord* obj_ptr = NULL;
399 // Try slow-path allocation unless we're allocating old and old is already full.
400 if (!(dest_attr->is_old() && _old_gen_is_full)) {
401 bool plab_refill_failed = false;
402 obj_ptr = _plab_allocator->allocate_direct_or_new_plab(*dest_attr,
403 word_sz,
404 &plab_refill_failed,
405 node_index);
406 if (obj_ptr == NULL) {
407 obj_ptr = allocate_in_next_plab(dest_attr,
408 word_sz,
409 plab_refill_failed,
410 node_index);
411 }
412 }
413 if (obj_ptr != NULL) {
414 update_numa_stats(node_index);
415 if (_g1h->gc_tracer_stw()->should_report_promotion_events()) {
416 // The events are checked individually as part of the actual commit
417 report_promotion_event(*dest_attr, old, klass, word_sz, age, obj_ptr, node_index);
418 }
419 }
420 return obj_ptr;
421 }
422
423 #if EVAC_FAILURE_INJECTOR
424 bool G1ParScanThreadState::inject_evacuation_failure(uint region_idx) {
425 return _g1h->evac_failure_injector()->evacuation_should_fail(_evac_failure_inject_counter, region_idx);
426 }
427 #endif
428
429 NOINLINE
430 void G1ParScanThreadState::undo_allocation(G1HeapRegionAttr dest_attr,
431 HeapWord* obj_ptr,
432 size_t word_sz,
433 uint node_index) {
434 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
435 }
436
437 void G1ParScanThreadState::update_bot_after_copying(oop obj, size_t word_sz) {
438 HeapWord* obj_start = cast_from_oop<HeapWord*>(obj);
439 HeapRegion* region = _g1h->heap_region_containing(obj_start);
440 region->update_bot_for_obj(obj_start, word_sz);
441 }
442
443 // Private inline function, for direct internal use and providing the
444 // implementation of the public not-inline function.
445 MAYBE_INLINE_EVACUATION
446 oop G1ParScanThreadState::do_copy_to_survivor_space(G1HeapRegionAttr const region_attr,
447 oop const old,
448 markWord const old_mark) {
449 assert(region_attr.is_in_cset(),
450 "Unexpected region attr type: %s", region_attr.get_type_str());
451
452 if (old_mark.is_marked()) {
453 // Already forwarded by somebody else, return forwardee.
454 return old->forwardee(old_mark);
455 }
456 // Get the klass once. We'll need it again later, and this avoids
457 // re-decoding when it's compressed.
458 Klass* klass;
459 #ifdef _LP64
460 if (UseCompactObjectHeaders) {
461 klass = old_mark.safe_klass();
462 } else
463 #endif
464 {
465 klass = old->klass();
466 }
467 const size_t word_sz = old->size_given_klass(klass);
468
469 uint age = 0;
470 G1HeapRegionAttr dest_attr = next_region_attr(region_attr, old_mark, age);
471 HeapRegion* const from_region = _g1h->heap_region_containing(old);
472 uint node_index = from_region->node_index();
473
474 HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_attr, word_sz, node_index);
475
476 // PLAB allocations should succeed most of the time, so we'll
477 // normally check against NULL once and that's it.
478 if (obj_ptr == NULL) {
479 obj_ptr = allocate_copy_slow(&dest_attr, old, klass, word_sz, age, node_index);
480 if (obj_ptr == NULL) {
481 // This will either forward-to-self, or detect that someone else has
482 // installed a forwarding pointer.
483 return handle_evacuation_failure_par(old, old_mark, word_sz);
484 }
485 }
486
487 assert(obj_ptr != NULL, "when we get here, allocation should have succeeded");
488 assert(_g1h->is_in_reserved(obj_ptr), "Allocated memory should be in the heap");
489
490 // Should this evacuation fail?
491 if (inject_evacuation_failure(from_region->hrm_index())) {
492 // Doing this after all the allocation attempts also tests the
493 // undo_allocation() method too.
494 undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
495 return handle_evacuation_failure_par(old, old_mark, word_sz);
496 }
497
498 // We're going to allocate linearly, so might as well prefetch ahead.
499 Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);
500 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(old), obj_ptr, word_sz);
501
502 const oop obj = cast_to_oop(obj_ptr);
503 // Because the forwarding is done with memory_order_relaxed there is no
504 // ordering with the above copy. Clients that get the forwardee must not
505 // examine its contents without other synchronization, since the contents
506 // may not be up to date for them.
507 const oop forward_ptr = old->forward_to_atomic(obj, old_mark, memory_order_relaxed);
508 if (forward_ptr == NULL) {
509
510 {
511 const uint young_index = from_region->young_index_in_cset();
512 assert((from_region->is_young() && young_index > 0) ||
513 (!from_region->is_young() && young_index == 0), "invariant" );
514 _surviving_young_words[young_index] += word_sz;
515 }
516
517 if (dest_attr.is_young()) {
518 if (age < markWord::max_age) {
519 age++;
520 obj->incr_age();
521 }
522 _age_table.add(age, word_sz);
523 } else {
524 update_bot_after_copying(obj, word_sz);
525 }
526
527 // Most objects are not arrays, so do one array check rather than
528 // checking for each array category for each object.
529 if (klass->is_array_klass()) {
530 if (klass->is_objArray_klass()) {
531 start_partial_objarray(dest_attr, old, obj);
532 } else {
533 // Nothing needs to be done for typeArrays. Body doesn't contain
534 // any oops to scan, and the type in the klass will already be handled
535 // by processing the built-in module.
536 assert(klass->is_typeArray_klass(), "invariant");
537 }
538 return obj;
539 }
540
541 ContinuationGCSupport::transform_stack_chunk(obj);
542
543 // Check for deduplicating young Strings.
544 if (G1StringDedup::is_candidate_from_evacuation(klass,
545 region_attr,
546 dest_attr,
547 age)) {
548 // Record old; request adds a new weak reference, which reference
549 // processing expects to refer to a from-space object.
550 _string_dedup_requests.add(old);
551 }
552
553 // Skip the card enqueue iff the object (obj) is in survivor region.
554 // However, HeapRegion::is_survivor() is too expensive here.
555 // Instead, we use dest_attr.is_young() because the two values are always
556 // equal: successfully allocated young regions must be survivor regions.
557 assert(dest_attr.is_young() == _g1h->heap_region_containing(obj)->is_survivor(), "must be");
558 G1SkipCardEnqueueSetter x(&_scanner, dest_attr.is_young());
559 obj->oop_iterate_backwards(&_scanner, klass);
560 return obj;
561 } else {
562 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index);
563 return forward_ptr;
564 }
565 }
566
567 // Public not-inline entry point.
568 ATTRIBUTE_FLATTEN
569 oop G1ParScanThreadState::copy_to_survivor_space(G1HeapRegionAttr region_attr,
570 oop old,
571 markWord old_mark) {
572 return do_copy_to_survivor_space(region_attr, old, old_mark);
573 }
574
575 G1ParScanThreadState* G1ParScanThreadStateSet::state_for_worker(uint worker_id) {
576 assert(worker_id < _n_workers, "out of bounds access");
577 if (_states[worker_id] == NULL) {
578 _states[worker_id] =
579 new G1ParScanThreadState(_g1h, rdcqs(),
580 _preserved_marks_set.get(worker_id),
581 worker_id, _n_workers,
582 _young_cset_length, _optional_cset_length,
583 _evac_failure_regions);
584 }
585 return _states[worker_id];
586 }
587
588 const size_t* G1ParScanThreadStateSet::surviving_young_words() const {
589 assert(_flushed, "thread local state from the per thread states should have been flushed");
590 return _surviving_young_words_total;
591 }
592
593 void G1ParScanThreadStateSet::flush_stats() {
594 assert(!_flushed, "thread local state from the per thread states should be flushed once");
595
596 for (uint worker_id = 0; worker_id < _n_workers; ++worker_id) {
597 G1ParScanThreadState* pss = _states[worker_id];
598 assert(pss != nullptr, "must be initialized");
599
600 G1GCPhaseTimes* p = _g1h->phase_times();
601
602 // Need to get the following two before the call to G1ParThreadScanState::flush()
603 // because it resets the PLAB allocator where we get this info from.
604 size_t lab_waste_bytes = pss->lab_waste_words() * HeapWordSize;
605 size_t lab_undo_waste_bytes = pss->lab_undo_waste_words() * HeapWordSize;
606 size_t copied_bytes = pss->flush_stats(_surviving_young_words_total, _n_workers) * HeapWordSize;
607
608 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, copied_bytes, G1GCPhaseTimes::MergePSSCopiedBytes);
609 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, lab_waste_bytes, G1GCPhaseTimes::MergePSSLABWasteBytes);
610 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, lab_undo_waste_bytes, G1GCPhaseTimes::MergePSSLABUndoWasteBytes);
611
612 delete pss;
613 _states[worker_id] = NULL;
614 }
615 _flushed = true;
616 }
617
618 void G1ParScanThreadStateSet::record_unused_optional_region(HeapRegion* hr) {
619 for (uint worker_index = 0; worker_index < _n_workers; ++worker_index) {
620 G1ParScanThreadState* pss = _states[worker_index];
621 assert(pss != nullptr, "must be initialized");
622
623 size_t used_memory = pss->oops_into_optional_region(hr)->used_memory();
624 _g1h->phase_times()->record_or_add_thread_work_item(G1GCPhaseTimes::OptScanHR, worker_index, used_memory, G1GCPhaseTimes::ScanHRUsedMemory);
625 }
626 }
627
628 NOINLINE
629 oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markWord m, size_t word_sz) {
630 assert(_g1h->is_in_cset(old), "Object " PTR_FORMAT " should be in the CSet", p2i(old));
631
632 oop forward_ptr = old->forward_to_self_atomic(m, memory_order_relaxed);
633 if (forward_ptr == NULL) {
634 // Forward-to-self succeeded. We are the "owner" of the object.
635 HeapRegion* r = _g1h->heap_region_containing(old);
636
637 if (_evac_failure_regions->record(r->hrm_index())) {
638 _g1h->hr_printer()->evac_failure(r);
639 }
640
641 // Mark the failing object in the marking bitmap and later use the bitmap to handle
642 // evacuation failure recovery.
643 _g1h->mark_evac_failure_object(_worker_id, old, word_sz);
644
645 _preserved_marks->push_if_necessary(old, m);
646
647 ContinuationGCSupport::transform_stack_chunk(old);
648
649 _evacuation_failed_info.register_copy_failure(word_sz);
650
651 // For iterating objects that failed evacuation currently we can reuse the
652 // existing closure to scan evacuated objects because:
653 // - for objects referring into the collection set we do not need to gather
654 // cards at this time. The regions they are in will be unconditionally turned
655 // to old regions without remembered sets.
656 // - since we are iterating from a collection set region (i.e. never a Survivor
657 // region), we always need to gather cards for this case.
658 G1SkipCardEnqueueSetter x(&_scanner, false /* skip_card_enqueue */);
659 old->oop_iterate_backwards(&_scanner);
660
661 return old;
662 } else {
663 // Forward-to-self failed. Either someone else managed to allocate
664 // space for this object (old != forward_ptr) or they beat us in
665 // self-forwarding it (old == forward_ptr).
666 assert(old == forward_ptr || !_g1h->is_in_cset(forward_ptr),
667 "Object " PTR_FORMAT " forwarded to: " PTR_FORMAT " "
668 "should not be in the CSet",
669 p2i(old), p2i(forward_ptr));
670 return forward_ptr;
671 }
672 }
673
674 void G1ParScanThreadState::initialize_numa_stats() {
675 if (_numa->is_enabled()) {
676 LogTarget(Info, gc, heap, numa) lt;
677
678 if (lt.is_enabled()) {
679 uint num_nodes = _numa->num_active_nodes();
680 // Record only if there are multiple active nodes.
681 _obj_alloc_stat = NEW_C_HEAP_ARRAY(size_t, num_nodes, mtGC);
682 memset(_obj_alloc_stat, 0, sizeof(size_t) * num_nodes);
683 }
684 }
685 }
686
687 void G1ParScanThreadState::flush_numa_stats() {
688 if (_obj_alloc_stat != NULL) {
689 uint node_index = _numa->index_of_current_thread();
690 _numa->copy_statistics(G1NUMAStats::LocalObjProcessAtCopyToSurv, node_index, _obj_alloc_stat);
691 }
692 }
693
694 void G1ParScanThreadState::update_numa_stats(uint node_index) {
695 if (_obj_alloc_stat != NULL) {
696 _obj_alloc_stat[node_index]++;
697 }
698 }
699
700 G1ParScanThreadStateSet::G1ParScanThreadStateSet(G1CollectedHeap* g1h,
701 uint n_workers,
702 size_t young_cset_length,
703 size_t optional_cset_length,
704 G1EvacFailureRegions* evac_failure_regions) :
705 _g1h(g1h),
706 _rdcqs(G1BarrierSet::dirty_card_queue_set().allocator()),
707 _preserved_marks_set(true /* in_c_heap */),
708 _states(NEW_C_HEAP_ARRAY(G1ParScanThreadState*, n_workers, mtGC)),
709 _surviving_young_words_total(NEW_C_HEAP_ARRAY(size_t, young_cset_length + 1, mtGC)),
710 _young_cset_length(young_cset_length),
711 _optional_cset_length(optional_cset_length),
712 _n_workers(n_workers),
713 _flushed(false),
714 _evac_failure_regions(evac_failure_regions) {
715 _preserved_marks_set.init(n_workers);
716 for (uint i = 0; i < n_workers; ++i) {
717 _states[i] = NULL;
718 }
719 memset(_surviving_young_words_total, 0, (young_cset_length + 1) * sizeof(size_t));
720 }
721
722 G1ParScanThreadStateSet::~G1ParScanThreadStateSet() {
723 assert(_flushed, "thread local state from the per thread states should have been flushed");
724 FREE_C_HEAP_ARRAY(G1ParScanThreadState*, _states);
725 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_total);
726 _preserved_marks_set.assert_empty();
727 _preserved_marks_set.reclaim();
728 }