1 /*
2 * Copyright (c) 1997, 2018, 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/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/blockOffsetTable.inline.hpp"
29 #include "gc/shared/collectedHeap.inline.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "gc/shared/genOopClosures.inline.hpp"
32 #include "gc/shared/space.hpp"
33 #include "gc/shared/space.inline.hpp"
34 #include "gc/shared/spaceDecorator.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/orderAccess.hpp"
40 #include "runtime/prefetch.inline.hpp"
41 #include "runtime/safepoint.hpp"
42 #include "utilities/align.hpp"
43 #include "utilities/copy.hpp"
44 #include "utilities/globalDefinitions.hpp"
45 #include "utilities/macros.hpp"
46 #if INCLUDE_SERIALGC
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 != NULL) {
53 if (_sp->block_is_obj(top_obj)) {
54 if (_precision == CardTable::ObjHeadPreciseArray) {
55 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
56 // An arrayOop is starting on the dirty card - since we do exact
57 // store checks for objArrays we are done.
58 } else {
59 // Otherwise, it is possible that the object starting on the dirty
60 // card spans the entire card, and that the store happened on a
61 // later card. Figure out where the object ends.
62 // Use the block_size() method of the space over which
63 // the iteration is being done. That space (e.g. CMS) may have
64 // specific requirements on object sizes which will
65 // be reflected in the block_size() method.
66 top = top_obj + oop(top_obj)->size();
67 }
68 }
69 } else {
70 top = top_obj;
71 }
72 } else {
73 assert(top == _sp->end(), "only case where top_obj == NULL");
74 }
75 return top;
76 }
77
78 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr,
79 HeapWord* bottom,
80 HeapWord* top) {
81 // 1. Blocks may or may not be objects.
82 // 2. Even when a block_is_obj(), it may not entirely
83 // occupy the block if the block quantum is larger than
84 // the object size.
85 // We can and should try to optimize by calling the non-MemRegion
86 // version of oop_iterate() for all but the extremal objects
87 // (for which we need to call the MemRegion version of
88 // oop_iterate()) To be done post-beta XXX
89 for (; bottom < top; bottom += _sp->block_size(bottom)) {
90 // As in the case of contiguous space above, we'd like to
91 // just use the value returned by oop_iterate to increment the
92 // current pointer; unfortunately, that won't work in CMS because
93 // we'd need an interface change (it seems) to have the space
94 // "adjust the object size" (for instance pad it up to its
95 // block alignment or minimum block size restrictions. XXX
96 if (_sp->block_is_obj(bottom) &&
97 !_sp->obj_allocated_since_save_marks(oop(bottom))) {
98 oop(bottom)->oop_iterate(_cl, mr);
99 }
100 }
101 }
102
103 // We get called with "mr" representing the dirty region
104 // that we want to process. Because of imprecise marking,
105 // we may need to extend the incoming "mr" to the right,
106 // and scan more. However, because we may already have
107 // scanned some of that extended region, we may need to
108 // trim its right-end back some so we do not scan what
109 // we (or another worker thread) may already have scanned
110 // or planning to scan.
111 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) {
112
113 // Some collectors need to do special things whenever their dirty
114 // cards are processed. For instance, CMS must remember mutator updates
115 // (i.e. dirty cards) so as to re-scan mutated objects.
116 // Such work can be piggy-backed here on dirty card scanning, so as to make
117 // it slightly more efficient than doing a complete non-destructive pre-scan
118 // of the card table.
119 MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure();
120 if (pCl != NULL) {
121 pCl->do_MemRegion(mr);
122 }
123
124 HeapWord* bottom = mr.start();
125 HeapWord* last = mr.last();
126 HeapWord* top = mr.end();
127 HeapWord* bottom_obj;
128 HeapWord* top_obj;
129
130 assert(_precision == CardTable::ObjHeadPreciseArray ||
131 _precision == CardTable::Precise,
132 "Only ones we deal with for now.");
133
134 assert(_precision != CardTable::ObjHeadPreciseArray ||
135 _cl->idempotent() || _last_bottom == NULL ||
136 top <= _last_bottom,
137 "Not decreasing");
138 NOT_PRODUCT(_last_bottom = mr.start());
139
140 bottom_obj = _sp->block_start(bottom);
141 top_obj = _sp->block_start(last);
142
143 assert(bottom_obj <= bottom, "just checking");
144 assert(top_obj <= top, "just checking");
145
146 // Given what we think is the top of the memory region and
147 // the start of the object at the top, get the actual
148 // value of the top.
149 top = get_actual_top(top, top_obj);
150
151 // If the previous call did some part of this region, don't redo.
152 if (_precision == CardTable::ObjHeadPreciseArray &&
153 _min_done != NULL &&
154 _min_done < top) {
155 top = _min_done;
156 }
157
158 // Top may have been reset, and in fact may be below bottom,
159 // e.g. the dirty card region is entirely in a now free object
160 // -- something that could happen with a concurrent sweeper.
161 bottom = MIN2(bottom, top);
162 MemRegion extended_mr = MemRegion(bottom, top);
163 assert(bottom <= top &&
164 (_precision != CardTable::ObjHeadPreciseArray ||
165 _min_done == NULL ||
166 top <= _min_done),
167 "overlap!");
168
169 // Walk the region if it is not empty; otherwise there is nothing to do.
170 if (!extended_mr.is_empty()) {
171 walk_mem_region(extended_mr, bottom_obj, top);
172 }
173
174 // An idempotent closure might be applied in any order, so we don't
175 // record a _min_done for it.
176 if (!_cl->idempotent()) {
177 _min_done = bottom;
178 } else {
179 assert(_min_done == _last_explicit_min_done,
180 "Don't update _min_done for idempotent cl");
181 }
182 }
183
184 DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl,
185 CardTable::PrecisionStyle precision,
186 HeapWord* boundary,
187 bool parallel) {
188 return new DirtyCardToOopClosure(this, cl, precision, boundary);
189 }
190
191 HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top,
192 HeapWord* top_obj) {
193 if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) {
194 if (_precision == CardTable::ObjHeadPreciseArray) {
195 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
196 // An arrayOop is starting on the dirty card - since we do exact
197 // store checks for objArrays we are done.
198 } else {
199 // Otherwise, it is possible that the object starting on the dirty
200 // card spans the entire card, and that the store happened on a
201 // later card. Figure out where the object ends.
202 assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(),
203 "Block size and object size mismatch");
204 top = top_obj + oop(top_obj)->size();
205 }
206 }
207 } else {
208 top = (_sp->toContiguousSpace())->top();
209 }
210 return top;
211 }
212
213 void FilteringDCTOC::walk_mem_region(MemRegion mr,
214 HeapWord* bottom,
215 HeapWord* top) {
216 // Note that this assumption won't hold if we have a concurrent
217 // collector in this space, which may have freed up objects after
218 // they were dirtied and before the stop-the-world GC that is
219 // examining cards here.
220 assert(bottom < top, "ought to be at least one obj on a dirty card.");
221
222 if (_boundary != NULL) {
223 // We have a boundary outside of which we don't want to look
224 // at objects, so create a filtering closure around the
225 // oop closure before walking the region.
226 FilteringClosure filter(_boundary, _cl);
227 walk_mem_region_with_cl(mr, bottom, top, &filter);
228 } else {
229 // No boundary, simply walk the heap with the oop closure.
230 walk_mem_region_with_cl(mr, bottom, top, _cl);
231 }
232
233 }
234
235 // We must replicate this so that the static type of "FilteringClosure"
236 // (see above) is apparent at the oop_iterate calls.
237 #define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \
238 void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \
239 HeapWord* bottom, \
240 HeapWord* top, \
241 ClosureType* cl) { \
242 bottom += oop(bottom)->oop_iterate_size(cl, mr); \
243 if (bottom < top) { \
244 HeapWord* next_obj = bottom + oop(bottom)->size(); \
245 while (next_obj < top) { \
246 /* Bottom lies entirely below top, so we can call the */ \
247 /* non-memRegion version of oop_iterate below. */ \
248 oop(bottom)->oop_iterate(cl); \
249 bottom = next_obj; \
250 next_obj = bottom + oop(bottom)->size(); \
251 } \
252 /* Last object. */ \
253 oop(bottom)->oop_iterate(cl, mr); \
254 } \
255 }
256
257 // (There are only two of these, rather than N, because the split is due
258 // only to the introduction of the FilteringClosure, a local part of the
259 // impl of this abstraction.)
260 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure)
261 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure)
262
263 DirtyCardToOopClosure*
264 ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl,
265 CardTable::PrecisionStyle precision,
266 HeapWord* boundary,
267 bool parallel) {
268 return new ContiguousSpaceDCTOC(this, cl, precision, boundary);
269 }
270
271 void Space::initialize(MemRegion mr,
272 bool clear_space,
273 bool mangle_space) {
274 HeapWord* bottom = mr.start();
275 HeapWord* end = mr.end();
276 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
277 "invalid space boundaries");
278 set_bottom(bottom);
279 set_end(end);
280 if (clear_space) clear(mangle_space);
281 }
282
283 void Space::clear(bool mangle_space) {
284 if (ZapUnusedHeapArea && mangle_space) {
285 mangle_unused_area();
286 }
287 }
288
289 ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL),
290 _concurrent_iteration_safe_limit(NULL) {
291 _mangler = new GenSpaceMangler(this);
292 }
293
294 ContiguousSpace::~ContiguousSpace() {
295 delete _mangler;
296 }
297
298 void ContiguousSpace::initialize(MemRegion mr,
299 bool clear_space,
300 bool mangle_space)
301 {
302 CompactibleSpace::initialize(mr, clear_space, mangle_space);
303 set_concurrent_iteration_safe_limit(top());
304 }
305
306 void ContiguousSpace::clear(bool mangle_space) {
307 set_top(bottom());
308 set_saved_mark();
309 CompactibleSpace::clear(mangle_space);
310 }
311
312 bool ContiguousSpace::is_free_block(const HeapWord* p) const {
313 return p >= _top;
314 }
315
316 void OffsetTableContigSpace::clear(bool mangle_space) {
317 ContiguousSpace::clear(mangle_space);
318 _offsets.initialize_threshold();
319 }
320
321 void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
322 Space::set_bottom(new_bottom);
323 _offsets.set_bottom(new_bottom);
324 }
325
326 void OffsetTableContigSpace::set_end(HeapWord* new_end) {
327 // Space should not advertise an increase in size
328 // until after the underlying offset table has been enlarged.
329 _offsets.resize(pointer_delta(new_end, bottom()));
330 Space::set_end(new_end);
331 }
332
333 #ifndef PRODUCT
334
335 void ContiguousSpace::set_top_for_allocations(HeapWord* v) {
336 mangler()->set_top_for_allocations(v);
337 }
338 void ContiguousSpace::set_top_for_allocations() {
339 mangler()->set_top_for_allocations(top());
340 }
341 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) {
342 mangler()->check_mangled_unused_area(limit);
343 }
344
345 void ContiguousSpace::check_mangled_unused_area_complete() {
346 mangler()->check_mangled_unused_area_complete();
347 }
348
349 // Mangled only the unused space that has not previously
350 // been mangled and that has not been allocated since being
351 // mangled.
352 void ContiguousSpace::mangle_unused_area() {
353 mangler()->mangle_unused_area();
354 }
355 void ContiguousSpace::mangle_unused_area_complete() {
356 mangler()->mangle_unused_area_complete();
357 }
358 #endif // NOT_PRODUCT
359
360 void CompactibleSpace::initialize(MemRegion mr,
361 bool clear_space,
362 bool mangle_space) {
363 Space::initialize(mr, clear_space, mangle_space);
364 set_compaction_top(bottom());
365 _next_compaction_space = NULL;
366 }
367
368 void CompactibleSpace::clear(bool mangle_space) {
369 Space::clear(mangle_space);
370 _compaction_top = bottom();
371 }
372
373 HeapWord* CompactibleSpace::forward(oop q, size_t size,
374 CompactPoint* cp, HeapWord* compact_top) {
375 // q is alive
376 // First check if we should switch compaction space
377 assert(this == cp->space, "'this' should be current compaction space.");
378 size_t compaction_max_size = pointer_delta(end(), compact_top);
379 while (size > compaction_max_size) {
380 // switch to next compaction space
381 cp->space->set_compaction_top(compact_top);
382 cp->space = cp->space->next_compaction_space();
383 if (cp->space == NULL) {
384 cp->gen = GenCollectedHeap::heap()->young_gen();
385 assert(cp->gen != NULL, "compaction must succeed");
386 cp->space = cp->gen->first_compaction_space();
387 assert(cp->space != NULL, "generation must have a first compaction space");
388 }
389 compact_top = cp->space->bottom();
390 cp->space->set_compaction_top(compact_top);
391 cp->threshold = cp->space->initialize_threshold();
392 compaction_max_size = pointer_delta(cp->space->end(), compact_top);
393 }
394
395 // store the forwarding pointer into the mark word
396 if ((HeapWord*)q != compact_top) {
397 q->forward_to(oop(compact_top));
398 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
399 } else {
400 // if the object isn't moving we can just set the mark to the default
401 // mark and handle it specially later on.
402 q->init_mark_raw();
403 assert(q->forwardee() == NULL, "should be forwarded to NULL");
404 }
405
406 compact_top += size;
407
408 // we need to update the offset table so that the beginnings of objects can be
409 // found during scavenge. Note that we are updating the offset table based on
410 // where the object will be once the compaction phase finishes.
411 if (compact_top > cp->threshold)
412 cp->threshold =
413 cp->space->cross_threshold(compact_top - size, compact_top);
414 return compact_top;
415 }
416
417 #if INCLUDE_SERIALGC
418
419 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) {
420 scan_and_forward(this, cp);
421 }
422
423 void CompactibleSpace::adjust_pointers() {
424 // Check first is there is any work to do.
425 if (used() == 0) {
426 return; // Nothing to do.
427 }
428
429 scan_and_adjust_pointers(this);
430 }
431
432 void CompactibleSpace::compact() {
433 scan_and_compact(this);
434 }
435
436 #endif // INCLUDE_SERIALGC
437
438 void Space::print_short() const { print_short_on(tty); }
439
440 void Space::print_short_on(outputStream* st) const {
441 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K,
442 (int) ((double) used() * 100 / capacity()));
443 }
444
445 void Space::print() const { print_on(tty); }
446
447 void Space::print_on(outputStream* st) const {
448 print_short_on(st);
449 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")",
450 p2i(bottom()), p2i(end()));
451 }
452
453 void ContiguousSpace::print_on(outputStream* st) const {
454 print_short_on(st);
455 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
456 p2i(bottom()), p2i(top()), p2i(end()));
457 }
458
459 void OffsetTableContigSpace::print_on(outputStream* st) const {
460 print_short_on(st);
461 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
462 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
463 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
464 }
465
466 void ContiguousSpace::verify() const {
467 HeapWord* p = bottom();
468 HeapWord* t = top();
469 HeapWord* prev_p = NULL;
470 while (p < t) {
471 oop(p)->verify();
472 prev_p = p;
473 p += oop(p)->size();
474 }
475 guarantee(p == top(), "end of last object must match end of space");
476 if (top() != end()) {
477 guarantee(top() == block_start_const(end()-1) &&
478 top() == block_start_const(top()),
479 "top should be start of unallocated block, if it exists");
480 }
481 }
482
483 void Space::oop_iterate(ExtendedOopClosure* blk) {
484 ObjectToOopClosure blk2(blk);
485 object_iterate(&blk2);
486 }
487
488 bool Space::obj_is_alive(const HeapWord* p) const {
489 assert (block_is_obj(p), "The address should point to an object");
490 return true;
491 }
492
493 void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) {
494 if (is_empty()) return;
495 HeapWord* obj_addr = bottom();
496 HeapWord* t = top();
497 // Could call objects iterate, but this is easier.
498 while (obj_addr < t) {
499 obj_addr += oop(obj_addr)->oop_iterate_size(blk);
500 }
501 }
502
503 void ContiguousSpace::object_iterate(ObjectClosure* blk) {
504 if (is_empty()) return;
505 object_iterate_from(bottom(), blk);
506 }
507
508 // For a ContiguousSpace object_iterate() and safe_object_iterate()
509 // are the same.
510 void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
511 object_iterate(blk);
512 }
513
514 void ContiguousSpace::object_iterate_from(HeapWord* mark, ObjectClosure* blk) {
515 while (mark < top()) {
516 blk->do_object(oop(mark));
517 mark += oop(mark)->size();
518 }
519 }
520
521 HeapWord*
522 ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) {
523 HeapWord * limit = concurrent_iteration_safe_limit();
524 assert(limit <= top(), "sanity check");
525 for (HeapWord* p = bottom(); p < limit;) {
526 size_t size = blk->do_object_careful(oop(p));
527 if (size == 0) {
528 return p; // failed at p
529 } else {
530 p += size;
531 }
532 }
533 return NULL; // all done
534 }
535
536 // Very general, slow implementation.
537 HeapWord* ContiguousSpace::block_start_const(const void* p) const {
538 assert(MemRegion(bottom(), end()).contains(p),
539 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
540 p2i(p), p2i(bottom()), p2i(end()));
541 if (p >= top()) {
542 return top();
543 } else {
544 HeapWord* last = bottom();
545 HeapWord* cur = last;
546 while (cur <= p) {
547 last = cur;
548 cur += oop(cur)->size();
549 }
550 assert(oopDesc::is_oop(oop(last)), PTR_FORMAT " should be an object start", p2i(last));
551 return last;
552 }
553 }
554
555 size_t ContiguousSpace::block_size(const HeapWord* 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 HeapWord* current_top = top();
560 assert(p <= current_top,
561 "p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT,
562 p2i(p), p2i(current_top));
563 assert(p == current_top || oopDesc::is_oop(oop(p)),
564 "p (" PTR_FORMAT ") is not a block start - "
565 "current_top: " PTR_FORMAT ", is_oop: %s",
566 p2i(p), p2i(current_top), BOOL_TO_STR(oopDesc::is_oop(oop(p))));
567 if (p < current_top) {
568 return oop(p)->size();
569 } else {
570 assert(p == current_top, "just checking");
571 return pointer_delta(end(), (HeapWord*) p);
572 }
573 }
574
575 // This version requires locking.
576 inline HeapWord* ContiguousSpace::allocate_impl(size_t size) {
577 assert(Heap_lock->owned_by_self() ||
578 (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()),
579 "not locked");
580 HeapWord* obj = top();
581 if (pointer_delta(end(), obj) >= size) {
582 HeapWord* new_top = obj + size;
583 set_top(new_top);
584 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
585 return obj;
586 } else {
587 return NULL;
588 }
589 }
590
591 // This version is lock-free.
592 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) {
593 do {
594 HeapWord* obj = top();
595 if (pointer_delta(end(), obj) >= size) {
596 HeapWord* new_top = obj + size;
597 HeapWord* result = Atomic::cmpxchg(new_top, top_addr(), obj);
598 // result can be one of two:
599 // the old top value: the exchange succeeded
600 // otherwise: the new value of the top is returned.
601 if (result == obj) {
602 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
603 return obj;
604 }
605 } else {
606 return NULL;
607 }
608 } while (true);
609 }
610
611 HeapWord* ContiguousSpace::allocate_aligned(size_t size) {
612 assert(Heap_lock->owned_by_self() || (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), "not locked");
613 HeapWord* end_value = end();
614
615 HeapWord* obj = CollectedHeap::align_allocation_or_fail(top(), end_value, SurvivorAlignmentInBytes);
616 if (obj == NULL) {
617 return NULL;
618 }
619
620 if (pointer_delta(end_value, obj) >= size) {
621 HeapWord* new_top = obj + size;
622 set_top(new_top);
623 assert(::is_aligned(obj, SurvivorAlignmentInBytes) && is_aligned(new_top),
624 "checking alignment");
625 return obj;
626 } else {
627 set_top(obj);
628 return NULL;
629 }
630 }
631
632 // Requires locking.
633 HeapWord* ContiguousSpace::allocate(size_t size) {
634 return allocate_impl(size);
635 }
636
637 // Lock-free.
638 HeapWord* ContiguousSpace::par_allocate(size_t size) {
639 return par_allocate_impl(size);
640 }
641
642 void ContiguousSpace::allocate_temporary_filler(int factor) {
643 // allocate temporary type array decreasing free size with factor 'factor'
644 assert(factor >= 0, "just checking");
645 size_t size = pointer_delta(end(), top());
646
647 // if space is full, return
648 if (size == 0) return;
649
650 if (factor > 0) {
651 size -= size/factor;
652 }
653 size = align_object_size(size);
654
655 const size_t array_header_size = typeArrayOopDesc::header_size(T_INT);
656 if (size >= align_object_size(array_header_size)) {
657 size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint));
658 // allocate uninitialized int array
659 typeArrayOop t = (typeArrayOop) allocate(size);
660 assert(t != NULL, "allocation should succeed");
661 t->set_mark_raw(markOopDesc::prototype());
662 t->set_klass(Universe::intArrayKlassObj());
663 t->set_length((int)length);
664 } else {
665 assert(size == CollectedHeap::min_fill_size(),
666 "size for smallest fake object doesn't match");
667 instanceOop obj = (instanceOop) allocate(size);
668 obj->set_mark_raw(markOopDesc::prototype());
669 obj->set_klass_gap(0);
670 obj->set_klass(SystemDictionary::Object_klass());
671 }
672 }
673
674 HeapWord* OffsetTableContigSpace::initialize_threshold() {
675 return _offsets.initialize_threshold();
676 }
677
678 HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) {
679 _offsets.alloc_block(start, end);
680 return _offsets.threshold();
681 }
682
683 OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray,
684 MemRegion mr) :
685 _offsets(sharedOffsetArray, mr),
686 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true)
687 {
688 _offsets.set_contig_space(this);
689 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle);
690 }
691
692 #define OBJ_SAMPLE_INTERVAL 0
693 #define BLOCK_SAMPLE_INTERVAL 100
694
695 void OffsetTableContigSpace::verify() const {
696 HeapWord* p = bottom();
697 HeapWord* prev_p = NULL;
698 int objs = 0;
699 int blocks = 0;
700
701 if (VerifyObjectStartArray) {
702 _offsets.verify();
703 }
704
705 while (p < top()) {
706 size_t size = oop(p)->size();
707 // For a sampling of objects in the space, find it using the
708 // block offset table.
709 if (blocks == BLOCK_SAMPLE_INTERVAL) {
710 guarantee(p == block_start_const(p + (size/2)),
711 "check offset computation");
712 blocks = 0;
713 } else {
714 blocks++;
715 }
716
717 if (objs == OBJ_SAMPLE_INTERVAL) {
718 oop(p)->verify();
719 objs = 0;
720 } else {
721 objs++;
722 }
723 prev_p = p;
724 p += size;
725 }
726 guarantee(p == top(), "end of last object must match end of space");
727 }
728
729
730 size_t TenuredSpace::allowed_dead_ratio() const {
731 return MarkSweepDeadRatio;
732 }