1 /*
2 * Copyright (c) 1997, 2023, 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 "classfile/vmClasses.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/collectedHeap.inline.hpp"
29 #include "gc/shared/genCollectedHeap.hpp"
30 #include "gc/shared/gcForwarding.inline.hpp"
31 #include "gc/shared/space.hpp"
32 #include "gc/shared/space.inline.hpp"
33 #include "gc/shared/spaceDecorator.inline.hpp"
34 #include "memory/iterator.inline.hpp"
35 #include "memory/universe.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/java.hpp"
39 #include "runtime/prefetch.inline.hpp"
40 #include "runtime/safepoint.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/copy.hpp"
43 #include "utilities/globalDefinitions.hpp"
44 #include "utilities/macros.hpp"
45 #if INCLUDE_SERIALGC
46 #include "gc/serial/serialBlockOffsetTable.inline.hpp"
47 #include "gc/serial/defNewGeneration.hpp"
48 #endif
49
50 HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top,
51 HeapWord* top_obj) {
52 if (top_obj != nullptr && top_obj < (_sp->toContiguousSpace())->top()) {
53 if (cast_to_oop(top_obj)->is_objArray() || cast_to_oop(top_obj)->is_typeArray()) {
54 // An arrayOop is starting on the dirty card - since we do exact
55 // store checks for objArrays we are done.
56 } else {
57 // Otherwise, it is possible that the object starting on the dirty
58 // card spans the entire card, and that the store happened on a
59 // later card. Figure out where the object ends.
60 assert(_sp->block_size(top_obj) == cast_to_oop(top_obj)->size(),
61 "Block size and object size mismatch");
62 top = top_obj + cast_to_oop(top_obj)->size();
63 }
64 } else {
65 top = (_sp->toContiguousSpace())->top();
66 }
67 return top;
68 }
69
70 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr,
71 HeapWord* bottom,
72 HeapWord* top) {
73 // Note that this assumption won't hold if we have a concurrent
74 // collector in this space, which may have freed up objects after
75 // they were dirtied and before the stop-the-world GC that is
76 // examining cards here.
77 assert(bottom < top, "ought to be at least one obj on a dirty card.");
78
79 walk_mem_region_with_cl(mr, bottom, top, _cl);
80 }
81
82 // We get called with "mr" representing the dirty region
83 // that we want to process. Because of imprecise marking,
84 // we may need to extend the incoming "mr" to the right,
85 // and scan more. However, because we may already have
86 // scanned some of that extended region, we may need to
87 // trim its right-end back some so we do not scan what
88 // we (or another worker thread) may already have scanned
89 // or planning to scan.
90 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) {
91 HeapWord* bottom = mr.start();
92 HeapWord* last = mr.last();
93 HeapWord* top = mr.end();
94 HeapWord* bottom_obj;
95 HeapWord* top_obj;
96
97 assert(_last_bottom == nullptr || top <= _last_bottom,
98 "Not decreasing");
99 NOT_PRODUCT(_last_bottom = mr.start());
100
101 bottom_obj = _sp->block_start(bottom);
102 top_obj = _sp->block_start(last);
103
104 assert(bottom_obj <= bottom, "just checking");
105 assert(top_obj <= top, "just checking");
106
107 // Given what we think is the top of the memory region and
108 // the start of the object at the top, get the actual
109 // value of the top.
110 top = get_actual_top(top, top_obj);
111
112 // If the previous call did some part of this region, don't redo.
113 if (_min_done != nullptr && _min_done < top) {
114 top = _min_done;
115 }
116
117 // Top may have been reset, and in fact may be below bottom,
118 // e.g. the dirty card region is entirely in a now free object
119 // -- something that could happen with a concurrent sweeper.
120 bottom = MIN2(bottom, top);
121 MemRegion extended_mr = MemRegion(bottom, top);
122 assert(bottom <= top &&
123 (_min_done == nullptr || top <= _min_done),
124 "overlap!");
125
126 // Walk the region if it is not empty; otherwise there is nothing to do.
127 if (!extended_mr.is_empty()) {
128 walk_mem_region(extended_mr, bottom_obj, top);
129 }
130
131 _min_done = bottom;
132 }
133
134 void DirtyCardToOopClosure::walk_mem_region_with_cl(MemRegion mr,
135 HeapWord* bottom,
136 HeapWord* top,
137 OopIterateClosure* cl) {
138 bottom += cast_to_oop(bottom)->oop_iterate_size(cl, mr);
139 if (bottom < top) {
140 HeapWord* next_obj = bottom + cast_to_oop(bottom)->size();
141 while (next_obj < top) {
142 /* Bottom lies entirely below top, so we can call the */
143 /* non-memRegion version of oop_iterate below. */
144 cast_to_oop(bottom)->oop_iterate(cl);
145 bottom = next_obj;
146 next_obj = bottom + cast_to_oop(bottom)->size();
147 }
148 /* Last object. */
149 cast_to_oop(bottom)->oop_iterate(cl, mr);
150 }
151 }
152
153 void Space::initialize(MemRegion mr,
154 bool clear_space,
155 bool mangle_space) {
156 HeapWord* bottom = mr.start();
157 HeapWord* end = mr.end();
158 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
159 "invalid space boundaries");
160 set_bottom(bottom);
161 set_end(end);
162 if (clear_space) clear(mangle_space);
163 }
164
165 void Space::clear(bool mangle_space) {
166 if (ZapUnusedHeapArea && mangle_space) {
167 mangle_unused_area();
168 }
169 }
170
171 ContiguousSpace::ContiguousSpace(): Space(),
172 _compaction_top(nullptr),
173 _next_compaction_space(nullptr),
174 _top(nullptr) {
175 _mangler = new GenSpaceMangler(this);
176 }
177
178 ContiguousSpace::~ContiguousSpace() {
179 delete _mangler;
180 }
181
182 void ContiguousSpace::initialize(MemRegion mr,
183 bool clear_space,
184 bool mangle_space)
185 {
186 Space::initialize(mr, clear_space, mangle_space);
187 set_compaction_top(bottom());
188 _next_compaction_space = nullptr;
189 }
190
191 void ContiguousSpace::clear(bool mangle_space) {
192 set_top(bottom());
193 set_saved_mark();
194 Space::clear(mangle_space);
195 _compaction_top = bottom();
196 }
197
198 bool ContiguousSpace::is_free_block(const HeapWord* p) const {
199 return p >= _top;
200 }
201
202 #if INCLUDE_SERIALGC
203 void TenuredSpace::clear(bool mangle_space) {
204 ContiguousSpace::clear(mangle_space);
205 _offsets.initialize_threshold();
206 }
207
208 void TenuredSpace::set_bottom(HeapWord* new_bottom) {
209 Space::set_bottom(new_bottom);
210 _offsets.set_bottom(new_bottom);
211 }
212
213 void TenuredSpace::set_end(HeapWord* new_end) {
214 // Space should not advertise an increase in size
215 // until after the underlying offset table has been enlarged.
216 _offsets.resize(pointer_delta(new_end, bottom()));
217 Space::set_end(new_end);
218 }
219 #endif // INCLUDE_SERIALGC
220
221 #ifndef PRODUCT
222
223 void ContiguousSpace::set_top_for_allocations(HeapWord* v) {
224 mangler()->set_top_for_allocations(v);
225 }
226 void ContiguousSpace::set_top_for_allocations() {
227 mangler()->set_top_for_allocations(top());
228 }
229 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) {
230 mangler()->check_mangled_unused_area(limit);
231 }
232
233 void ContiguousSpace::check_mangled_unused_area_complete() {
234 mangler()->check_mangled_unused_area_complete();
235 }
236
237 // Mangled only the unused space that has not previously
238 // been mangled and that has not been allocated since being
239 // mangled.
240 void ContiguousSpace::mangle_unused_area() {
241 mangler()->mangle_unused_area();
242 }
243 void ContiguousSpace::mangle_unused_area_complete() {
244 mangler()->mangle_unused_area_complete();
245 }
246 #endif // NOT_PRODUCT
247
248
249 HeapWord* ContiguousSpace::forward(oop q, size_t size,
250 CompactPoint* cp, HeapWord* compact_top) {
251 // q is alive
252 // First check if we should switch compaction space
253 assert(this == cp->space, "'this' should be current compaction space.");
254 size_t compaction_max_size = pointer_delta(end(), compact_top);
255 while (size > compaction_max_size) {
256 // switch to next compaction space
257 cp->space->set_compaction_top(compact_top);
258 cp->space = cp->space->next_compaction_space();
259 if (cp->space == nullptr) {
260 cp->gen = GenCollectedHeap::heap()->young_gen();
261 assert(cp->gen != nullptr, "compaction must succeed");
262 cp->space = cp->gen->first_compaction_space();
263 assert(cp->space != nullptr, "generation must have a first compaction space");
264 }
265 compact_top = cp->space->bottom();
266 cp->space->set_compaction_top(compact_top);
267 cp->space->initialize_threshold();
268 compaction_max_size = pointer_delta(cp->space->end(), compact_top);
269 }
270
271 // store the forwarding pointer into the mark word
272 if (cast_from_oop<HeapWord*>(q) != compact_top) {
273 GCForwarding::forward_to(q, cast_to_oop(compact_top));
274 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
275 } else {
276 // if the object isn't moving we can just set the mark to the default
277 // mark and handle it specially later on.
278 q->init_mark();
279 assert(GCForwarding::is_not_forwarded(q), "should not be forwarded");
280 }
281
282 compact_top += size;
283
284 // We need to update the offset table so that the beginnings of objects can be
285 // found during scavenge. Note that we are updating the offset table based on
286 // where the object will be once the compaction phase finishes.
287 cp->space->alloc_block(compact_top - size, compact_top);
288 return compact_top;
289 }
290
291 #if INCLUDE_SERIALGC
292
293 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) {
294 // Compute the new addresses for the live objects and store it in the mark
295 // Used by universe::mark_sweep_phase2()
296
297 // We're sure to be here before any objects are compacted into this
298 // space, so this is a good time to initialize this:
299 set_compaction_top(bottom());
300
301 if (cp->space == nullptr) {
302 assert(cp->gen != nullptr, "need a generation");
303 assert(cp->gen->first_compaction_space() == this, "just checking");
304 cp->space = cp->gen->first_compaction_space();
305 cp->space->initialize_threshold();
306 cp->space->set_compaction_top(cp->space->bottom());
307 }
308
309 HeapWord* compact_top = cp->space->compaction_top(); // This is where we are currently compacting to.
310
311 DeadSpacer dead_spacer(this);
312
313 HeapWord* end_of_live = bottom(); // One byte beyond the last byte of the last live object.
314 HeapWord* first_dead = nullptr; // The first dead object.
315
316 const intx interval = PrefetchScanIntervalInBytes;
317
318 HeapWord* cur_obj = bottom();
319 HeapWord* scan_limit = top();
320
321 while (cur_obj < scan_limit) {
322 if (cast_to_oop(cur_obj)->is_gc_marked()) {
323 // prefetch beyond cur_obj
324 Prefetch::write(cur_obj, interval);
325 size_t size = cast_to_oop(cur_obj)->size();
326 compact_top = cp->space->forward(cast_to_oop(cur_obj), size, cp, compact_top);
327 cur_obj += size;
328 end_of_live = cur_obj;
329 } else {
330 // run over all the contiguous dead objects
331 HeapWord* end = cur_obj;
332 do {
333 // prefetch beyond end
334 Prefetch::write(end, interval);
335 end += cast_to_oop(end)->size();
336 } while (end < scan_limit && !cast_to_oop(end)->is_gc_marked());
337
338 // see if we might want to pretend this object is alive so that
339 // we don't have to compact quite as often.
340 if (cur_obj == compact_top && dead_spacer.insert_deadspace(cur_obj, end)) {
341 oop obj = cast_to_oop(cur_obj);
342 compact_top = cp->space->forward(obj, obj->size(), cp, compact_top);
343 end_of_live = end;
344 } else {
345 // otherwise, it really is a free region.
346
347 // cur_obj is a pointer to a dead object. Use this dead memory to store a pointer to the next live object.
348 *(HeapWord**)cur_obj = end;
349
350 // see if this is the first dead region.
351 if (first_dead == nullptr) {
352 first_dead = cur_obj;
353 }
354 }
355
356 // move on to the next object
357 cur_obj = end;
358 }
359 }
360
361 assert(cur_obj == scan_limit, "just checking");
362 _end_of_live = end_of_live;
363 if (first_dead != nullptr) {
364 _first_dead = first_dead;
365 } else {
366 _first_dead = end_of_live;
367 }
368
369 // save the compaction_top of the compaction space.
370 cp->space->set_compaction_top(compact_top);
371 }
372
373 void ContiguousSpace::adjust_pointers() {
374 // Check first is there is any work to do.
375 if (used() == 0) {
376 return; // Nothing to do.
377 }
378
379 // adjust all the interior pointers to point at the new locations of objects
380 // Used by MarkSweep::mark_sweep_phase3()
381
382 HeapWord* cur_obj = bottom();
383 HeapWord* const end_of_live = _end_of_live; // Established by prepare_for_compaction().
384 HeapWord* const first_dead = _first_dead; // Established by prepare_for_compaction().
385
386 assert(first_dead <= end_of_live, "Stands to reason, no?");
387
388 const intx interval = PrefetchScanIntervalInBytes;
389
390 debug_only(HeapWord* prev_obj = nullptr);
391 while (cur_obj < end_of_live) {
392 Prefetch::write(cur_obj, interval);
393 if (cur_obj < first_dead || cast_to_oop(cur_obj)->is_gc_marked()) {
394 // cur_obj is alive
395 // point all the oops to the new location
396 size_t size = MarkSweep::adjust_pointers(cast_to_oop(cur_obj));
397 debug_only(prev_obj = cur_obj);
398 cur_obj += size;
399 } else {
400 debug_only(prev_obj = cur_obj);
401 // cur_obj is not a live object, instead it points at the next live object
402 cur_obj = *(HeapWord**)cur_obj;
403 assert(cur_obj > prev_obj, "we should be moving forward through memory, cur_obj: " PTR_FORMAT ", prev_obj: " PTR_FORMAT, p2i(cur_obj), p2i(prev_obj));
404 }
405 }
406
407 assert(cur_obj == end_of_live, "just checking");
408 }
409
410 void ContiguousSpace::compact() {
411 // Copy all live objects to their new location
412 // Used by MarkSweep::mark_sweep_phase4()
413
414 verify_up_to_first_dead(this);
415
416 HeapWord* const start = bottom();
417 HeapWord* const end_of_live = _end_of_live;
418
419 assert(_first_dead <= end_of_live, "Invariant. _first_dead: " PTR_FORMAT " <= end_of_live: " PTR_FORMAT, p2i(_first_dead), p2i(end_of_live));
420 if (_first_dead == end_of_live && (start == end_of_live || !cast_to_oop(start)->is_gc_marked())) {
421 // Nothing to compact. The space is either empty or all live object should be left in place.
422 clear_empty_region(this);
423 return;
424 }
425
426 const intx scan_interval = PrefetchScanIntervalInBytes;
427 const intx copy_interval = PrefetchCopyIntervalInBytes;
428
429 assert(start < end_of_live, "bottom: " PTR_FORMAT " should be < end_of_live: " PTR_FORMAT, p2i(start), p2i(end_of_live));
430 HeapWord* cur_obj = start;
431 if (_first_dead > cur_obj && !cast_to_oop(cur_obj)->is_gc_marked()) {
432 // All object before _first_dead can be skipped. They should not be moved.
433 // A pointer to the first live object is stored at the memory location for _first_dead.
434 cur_obj = *(HeapWord**)(_first_dead);
435 }
436
437 debug_only(HeapWord* prev_obj = nullptr);
438 while (cur_obj < end_of_live) {
439 if (GCForwarding::is_not_forwarded(cast_to_oop(cur_obj))) {
440 debug_only(prev_obj = cur_obj);
441 // The first word of the dead object contains a pointer to the next live object or end of space.
442 cur_obj = *(HeapWord**)cur_obj;
443 assert(cur_obj > prev_obj, "we should be moving forward through memory");
444 } else {
445 // prefetch beyond q
446 Prefetch::read(cur_obj, scan_interval);
447
448 // size and destination
449 size_t size = cast_to_oop(cur_obj)->size();
450 HeapWord* compaction_top = cast_from_oop<HeapWord*>(GCForwarding::forwardee(cast_to_oop(cur_obj)));
451
452 // prefetch beyond compaction_top
453 Prefetch::write(compaction_top, copy_interval);
454
455 // copy object and reinit its mark
456 assert(cur_obj != compaction_top, "everything in this pass should be moving");
457 Copy::aligned_conjoint_words(cur_obj, compaction_top, size);
458 oop new_obj = cast_to_oop(compaction_top);
459
460 ContinuationGCSupport::transform_stack_chunk(new_obj);
461
462 new_obj->init_mark();
463 assert(new_obj->klass() != nullptr, "should have a class");
464
465 debug_only(prev_obj = cur_obj);
466 cur_obj += size;
467 }
468 }
469
470 clear_empty_region(this);
471 }
472
473 #endif // INCLUDE_SERIALGC
474
475 void Space::print_short() const { print_short_on(tty); }
476
477 void Space::print_short_on(outputStream* st) const {
478 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K,
479 (int) ((double) used() * 100 / capacity()));
480 }
481
482 void Space::print() const { print_on(tty); }
483
484 void Space::print_on(outputStream* st) const {
485 print_short_on(st);
486 st->print_cr(" [" PTR_FORMAT ", " PTR_FORMAT ")",
487 p2i(bottom()), p2i(end()));
488 }
489
490 void ContiguousSpace::print_on(outputStream* st) const {
491 print_short_on(st);
492 st->print_cr(" [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ")",
493 p2i(bottom()), p2i(top()), p2i(end()));
494 }
495
496 #if INCLUDE_SERIALGC
497 void TenuredSpace::print_on(outputStream* st) const {
498 print_short_on(st);
499 st->print_cr(" [" PTR_FORMAT ", " PTR_FORMAT ", "
500 PTR_FORMAT ", " PTR_FORMAT ")",
501 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
502 }
503 #endif
504
505 void ContiguousSpace::verify() const {
506 HeapWord* p = bottom();
507 HeapWord* t = top();
508 HeapWord* prev_p = nullptr;
509 while (p < t) {
510 oopDesc::verify(cast_to_oop(p));
511 prev_p = p;
512 p += cast_to_oop(p)->size();
513 }
514 guarantee(p == top(), "end of last object must match end of space");
515 if (top() != end()) {
516 guarantee(top() == block_start_const(end()-1) &&
517 top() == block_start_const(top()),
518 "top should be start of unallocated block, if it exists");
519 }
520 }
521
522 void Space::oop_iterate(OopIterateClosure* blk) {
523 ObjectToOopClosure blk2(blk);
524 object_iterate(&blk2);
525 }
526
527 bool Space::obj_is_alive(const HeapWord* p) const {
528 assert (block_is_obj(p), "The address should point to an object");
529 return true;
530 }
531
532 void ContiguousSpace::oop_iterate(OopIterateClosure* blk) {
533 if (is_empty()) return;
534 HeapWord* obj_addr = bottom();
535 HeapWord* t = top();
536 // Could call objects iterate, but this is easier.
537 while (obj_addr < t) {
538 obj_addr += cast_to_oop(obj_addr)->oop_iterate_size(blk);
539 }
540 }
541
542 void ContiguousSpace::object_iterate(ObjectClosure* blk) {
543 if (is_empty()) return;
544 object_iterate_from(bottom(), blk);
545 }
546
547 void ContiguousSpace::object_iterate_from(HeapWord* mark, ObjectClosure* blk) {
548 while (mark < top()) {
549 blk->do_object(cast_to_oop(mark));
550 mark += cast_to_oop(mark)->size();
551 }
552 }
553
554 // Very general, slow implementation.
555 HeapWord* ContiguousSpace::block_start_const(const void* p) const {
556 assert(MemRegion(bottom(), end()).contains(p),
557 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
558 p2i(p), p2i(bottom()), p2i(end()));
559 if (p >= top()) {
560 return top();
561 } else {
562 HeapWord* last = bottom();
563 HeapWord* cur = last;
564 while (cur <= p) {
565 last = cur;
566 cur += cast_to_oop(cur)->size();
567 }
568 assert(oopDesc::is_oop(cast_to_oop(last)), PTR_FORMAT " should be an object start", p2i(last));
569 return last;
570 }
571 }
572
573 size_t ContiguousSpace::block_size(const HeapWord* p) const {
574 assert(MemRegion(bottom(), end()).contains(p),
575 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
576 p2i(p), p2i(bottom()), p2i(end()));
577 HeapWord* current_top = top();
578 assert(p <= current_top,
579 "p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT,
580 p2i(p), p2i(current_top));
581 assert(p == current_top || oopDesc::is_oop(cast_to_oop(p)),
582 "p (" PTR_FORMAT ") is not a block start - "
583 "current_top: " PTR_FORMAT ", is_oop: %s",
584 p2i(p), p2i(current_top), BOOL_TO_STR(oopDesc::is_oop(cast_to_oop(p))));
585 if (p < current_top) {
586 return cast_to_oop(p)->size();
587 } else {
588 assert(p == current_top, "just checking");
589 return pointer_delta(end(), (HeapWord*) p);
590 }
591 }
592
593 // This version requires locking.
594 inline HeapWord* ContiguousSpace::allocate_impl(size_t size) {
595 assert(Heap_lock->owned_by_self() ||
596 (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()),
597 "not locked");
598 HeapWord* obj = top();
599 if (pointer_delta(end(), obj) >= size) {
600 HeapWord* new_top = obj + size;
601 set_top(new_top);
602 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
603 return obj;
604 } else {
605 return nullptr;
606 }
607 }
608
609 // This version is lock-free.
610 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) {
611 do {
612 HeapWord* obj = top();
613 if (pointer_delta(end(), obj) >= size) {
614 HeapWord* new_top = obj + size;
615 HeapWord* result = Atomic::cmpxchg(top_addr(), obj, new_top);
616 // result can be one of two:
617 // the old top value: the exchange succeeded
618 // otherwise: the new value of the top is returned.
619 if (result == obj) {
620 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
621 return obj;
622 }
623 } else {
624 return nullptr;
625 }
626 } while (true);
627 }
628
629 // Requires locking.
630 HeapWord* ContiguousSpace::allocate(size_t size) {
631 return allocate_impl(size);
632 }
633
634 // Lock-free.
635 HeapWord* ContiguousSpace::par_allocate(size_t size) {
636 return par_allocate_impl(size);
637 }
638
639 #if INCLUDE_SERIALGC
640 void TenuredSpace::initialize_threshold() {
641 _offsets.initialize_threshold();
642 }
643
644 void TenuredSpace::alloc_block(HeapWord* start, HeapWord* end) {
645 _offsets.alloc_block(start, end);
646 }
647
648 TenuredSpace::TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray,
649 MemRegion mr) :
650 _offsets(sharedOffsetArray, mr),
651 _par_alloc_lock(Mutex::safepoint, "TenuredSpaceParAlloc_lock", true)
652 {
653 _offsets.set_contig_space(this);
654 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle);
655 }
656
657 #define OBJ_SAMPLE_INTERVAL 0
658 #define BLOCK_SAMPLE_INTERVAL 100
659
660 void TenuredSpace::verify() const {
661 HeapWord* p = bottom();
662 HeapWord* prev_p = nullptr;
663 int objs = 0;
664 int blocks = 0;
665
666 if (VerifyObjectStartArray) {
667 _offsets.verify();
668 }
669
670 while (p < top()) {
671 size_t size = cast_to_oop(p)->size();
672 // For a sampling of objects in the space, find it using the
673 // block offset table.
674 if (blocks == BLOCK_SAMPLE_INTERVAL) {
675 guarantee(p == block_start_const(p + (size/2)),
676 "check offset computation");
677 blocks = 0;
678 } else {
679 blocks++;
680 }
681
682 if (objs == OBJ_SAMPLE_INTERVAL) {
683 oopDesc::verify(cast_to_oop(p));
684 objs = 0;
685 } else {
686 objs++;
687 }
688 prev_p = p;
689 p += size;
690 }
691 guarantee(p == top(), "end of last object must match end of space");
692 }
693
694
695 size_t TenuredSpace::allowed_dead_ratio() const {
696 return MarkSweepDeadRatio;
697 }
698 #endif // INCLUDE_SERIALGC