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/iterator.inline.hpp" 36 #include "memory/universe.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "runtime/atomic.hpp" 39 #include "runtime/java.hpp" 40 #include "runtime/orderAccess.hpp" 41 #include "runtime/prefetch.inline.hpp" 42 #include "runtime/safepoint.hpp" 43 #include "utilities/align.hpp" 44 #include "utilities/copy.hpp" 45 #include "utilities/globalDefinitions.hpp" 46 #include "utilities/macros.hpp" 47 #if INCLUDE_SERIALGC 48 #include "gc/serial/defNewGeneration.hpp" 49 #endif 50 51 HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top, 52 HeapWord* top_obj) { 53 if (top_obj != NULL) { 54 if (_sp->block_is_obj(top_obj)) { 55 if (_precision == CardTable::ObjHeadPreciseArray) { 56 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { 57 // An arrayOop is starting on the dirty card - since we do exact 58 // store checks for objArrays we are done. 59 } else { 60 // Otherwise, it is possible that the object starting on the dirty 61 // card spans the entire card, and that the store happened on a 62 // later card. Figure out where the object ends. 63 // Use the block_size() method of the space over which 64 // the iteration is being done. That space (e.g. CMS) may have 65 // specific requirements on object sizes which will 66 // be reflected in the block_size() method. 67 top = top_obj + oop(top_obj)->size(); 68 } 69 } 70 } else { 71 top = top_obj; 72 } 73 } else { 74 assert(top == _sp->end(), "only case where top_obj == NULL"); 75 } 76 return top; 77 } 78 79 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr, 80 HeapWord* bottom, 81 HeapWord* top) { 82 // 1. Blocks may or may not be objects. 83 // 2. Even when a block_is_obj(), it may not entirely 84 // occupy the block if the block quantum is larger than 85 // the object size. 86 // We can and should try to optimize by calling the non-MemRegion 87 // version of oop_iterate() for all but the extremal objects 88 // (for which we need to call the MemRegion version of 89 // oop_iterate()) To be done post-beta XXX 90 for (; bottom < top; bottom += _sp->block_size(bottom)) { 91 // As in the case of contiguous space above, we'd like to 92 // just use the value returned by oop_iterate to increment the 93 // current pointer; unfortunately, that won't work in CMS because 94 // we'd need an interface change (it seems) to have the space 95 // "adjust the object size" (for instance pad it up to its 96 // block alignment or minimum block size restrictions. XXX 97 if (_sp->block_is_obj(bottom) && 98 !_sp->obj_allocated_since_save_marks(oop(bottom))) { 99 oop(bottom)->oop_iterate(_cl, mr); 100 } 101 } 102 } 103 104 // We get called with "mr" representing the dirty region 105 // that we want to process. Because of imprecise marking, 106 // we may need to extend the incoming "mr" to the right, 107 // and scan more. However, because we may already have 108 // scanned some of that extended region, we may need to 109 // trim its right-end back some so we do not scan what 110 // we (or another worker thread) may already have scanned 111 // or planning to scan. 112 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) { 113 114 // Some collectors need to do special things whenever their dirty 115 // cards are processed. For instance, CMS must remember mutator updates 116 // (i.e. dirty cards) so as to re-scan mutated objects. 117 // Such work can be piggy-backed here on dirty card scanning, so as to make 118 // it slightly more efficient than doing a complete non-destructive pre-scan 119 // of the card table. 120 MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure(); 121 if (pCl != NULL) { 122 pCl->do_MemRegion(mr); 123 } 124 125 HeapWord* bottom = mr.start(); 126 HeapWord* last = mr.last(); 127 HeapWord* top = mr.end(); 128 HeapWord* bottom_obj; 129 HeapWord* top_obj; 130 131 assert(_precision == CardTable::ObjHeadPreciseArray || 132 _precision == CardTable::Precise, 133 "Only ones we deal with for now."); 134 135 assert(_precision != CardTable::ObjHeadPreciseArray || 136 _last_bottom == NULL || 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 _min_done = bottom; 175 } 176 177 DirtyCardToOopClosure* Space::new_dcto_cl(OopIterateClosure* cl, 178 CardTable::PrecisionStyle precision, 179 HeapWord* boundary, 180 bool parallel) { 181 return new DirtyCardToOopClosure(this, cl, precision, boundary); 182 } 183 184 HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top, 185 HeapWord* top_obj) { 186 if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) { 187 if (_precision == CardTable::ObjHeadPreciseArray) { 188 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { 189 // An arrayOop is starting on the dirty card - since we do exact 190 // store checks for objArrays we are done. 191 } else { 192 // Otherwise, it is possible that the object starting on the dirty 193 // card spans the entire card, and that the store happened on a 194 // later card. Figure out where the object ends. 195 assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(), 196 "Block size and object size mismatch"); 197 top = top_obj + oop(top_obj)->size(); 198 } 199 } 200 } else { 201 top = (_sp->toContiguousSpace())->top(); 202 } 203 return top; 204 } 205 206 void FilteringDCTOC::walk_mem_region(MemRegion mr, 207 HeapWord* bottom, 208 HeapWord* top) { 209 // Note that this assumption won't hold if we have a concurrent 210 // collector in this space, which may have freed up objects after 211 // they were dirtied and before the stop-the-world GC that is 212 // examining cards here. 213 assert(bottom < top, "ought to be at least one obj on a dirty card."); 214 215 if (_boundary != NULL) { 216 // We have a boundary outside of which we don't want to look 217 // at objects, so create a filtering closure around the 218 // oop closure before walking the region. 219 FilteringClosure filter(_boundary, _cl); 220 walk_mem_region_with_cl(mr, bottom, top, &filter); 221 } else { 222 // No boundary, simply walk the heap with the oop closure. 223 walk_mem_region_with_cl(mr, bottom, top, _cl); 224 } 225 226 } 227 228 // We must replicate this so that the static type of "FilteringClosure" 229 // (see above) is apparent at the oop_iterate calls. 230 #define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ 231 void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \ 232 HeapWord* bottom, \ 233 HeapWord* top, \ 234 ClosureType* cl) { \ 235 bottom += oop(bottom)->oop_iterate_size(cl, mr); \ 236 if (bottom < top) { \ 237 HeapWord* next_obj = bottom + oop(bottom)->size(); \ 238 while (next_obj < top) { \ 239 /* Bottom lies entirely below top, so we can call the */ \ 240 /* non-memRegion version of oop_iterate below. */ \ 241 oop(bottom)->oop_iterate(cl); \ 242 bottom = next_obj; \ 243 next_obj = bottom + oop(bottom)->size(); \ 244 } \ 245 /* Last object. */ \ 246 oop(bottom)->oop_iterate(cl, mr); \ 247 } \ 248 } 249 250 // (There are only two of these, rather than N, because the split is due 251 // only to the introduction of the FilteringClosure, a local part of the 252 // impl of this abstraction.) 253 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(OopIterateClosure) 254 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) 255 256 DirtyCardToOopClosure* 257 ContiguousSpace::new_dcto_cl(OopIterateClosure* cl, 258 CardTable::PrecisionStyle precision, 259 HeapWord* boundary, 260 bool parallel) { 261 return new ContiguousSpaceDCTOC(this, cl, precision, boundary); 262 } 263 264 void Space::initialize(MemRegion mr, 265 bool clear_space, 266 bool mangle_space) { 267 HeapWord* bottom = mr.start(); 268 HeapWord* end = mr.end(); 269 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end), 270 "invalid space boundaries"); 271 set_bottom(bottom); 272 set_end(end); 273 if (clear_space) clear(mangle_space); 274 } 275 276 void Space::clear(bool mangle_space) { 277 if (ZapUnusedHeapArea && mangle_space) { 278 mangle_unused_area(); 279 } 280 } 281 282 ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL), 283 _concurrent_iteration_safe_limit(NULL) { 284 _mangler = new GenSpaceMangler(this); 285 } 286 287 ContiguousSpace::~ContiguousSpace() { 288 delete _mangler; 289 } 290 291 void ContiguousSpace::initialize(MemRegion mr, 292 bool clear_space, 293 bool mangle_space) 294 { 295 CompactibleSpace::initialize(mr, clear_space, mangle_space); 296 set_concurrent_iteration_safe_limit(top()); 297 } 298 299 void ContiguousSpace::clear(bool mangle_space) { 300 set_top(bottom()); 301 set_saved_mark(); 302 CompactibleSpace::clear(mangle_space); 303 } 304 305 bool ContiguousSpace::is_free_block(const HeapWord* p) const { 306 return p >= _top; 307 } 308 309 void OffsetTableContigSpace::clear(bool mangle_space) { 310 ContiguousSpace::clear(mangle_space); 311 _offsets.initialize_threshold(); 312 } 313 314 void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 315 Space::set_bottom(new_bottom); 316 _offsets.set_bottom(new_bottom); 317 } 318 319 void OffsetTableContigSpace::set_end(HeapWord* new_end) { 320 // Space should not advertise an increase in size 321 // until after the underlying offset table has been enlarged. 322 _offsets.resize(pointer_delta(new_end, bottom())); 323 Space::set_end(new_end); 324 } 325 326 #ifndef PRODUCT 327 328 void ContiguousSpace::set_top_for_allocations(HeapWord* v) { 329 mangler()->set_top_for_allocations(v); 330 } 331 void ContiguousSpace::set_top_for_allocations() { 332 mangler()->set_top_for_allocations(top()); 333 } 334 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) { 335 mangler()->check_mangled_unused_area(limit); 336 } 337 338 void ContiguousSpace::check_mangled_unused_area_complete() { 339 mangler()->check_mangled_unused_area_complete(); 340 } 341 342 // Mangled only the unused space that has not previously 343 // been mangled and that has not been allocated since being 344 // mangled. 345 void ContiguousSpace::mangle_unused_area() { 346 mangler()->mangle_unused_area(); 347 } 348 void ContiguousSpace::mangle_unused_area_complete() { 349 mangler()->mangle_unused_area_complete(); 350 } 351 #endif // NOT_PRODUCT 352 353 void CompactibleSpace::initialize(MemRegion mr, 354 bool clear_space, 355 bool mangle_space) { 356 Space::initialize(mr, clear_space, mangle_space); 357 set_compaction_top(bottom()); 358 _next_compaction_space = NULL; 359 } 360 361 void CompactibleSpace::clear(bool mangle_space) { 362 Space::clear(mangle_space); 363 _compaction_top = bottom(); 364 } 365 366 HeapWord* CompactibleSpace::forward(oop q, size_t size, 367 CompactPoint* cp, HeapWord* compact_top) { 368 // q is alive 369 // First check if we should switch compaction space 370 assert(this == cp->space, "'this' should be current compaction space."); 371 size_t compaction_max_size = pointer_delta(end(), compact_top); 372 while (size > compaction_max_size) { 373 // switch to next compaction space 374 cp->space->set_compaction_top(compact_top); 375 cp->space = cp->space->next_compaction_space(); 376 if (cp->space == NULL) { 377 cp->gen = GenCollectedHeap::heap()->young_gen(); 378 assert(cp->gen != NULL, "compaction must succeed"); 379 cp->space = cp->gen->first_compaction_space(); 380 assert(cp->space != NULL, "generation must have a first compaction space"); 381 } 382 compact_top = cp->space->bottom(); 383 cp->space->set_compaction_top(compact_top); 384 cp->threshold = cp->space->initialize_threshold(); 385 compaction_max_size = pointer_delta(cp->space->end(), compact_top); 386 } 387 388 // store the forwarding pointer into the mark word 389 if ((HeapWord*)q != compact_top) { 390 q->forward_to(oop(compact_top)); 391 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); 392 } else { 393 // if the object isn't moving we can just set the mark to the default 394 // mark and handle it specially later on. 395 q->init_mark_raw(); 396 assert(q->forwardee() == NULL, "should be forwarded to NULL"); 397 } 398 399 compact_top += size; 400 401 // we need to update the offset table so that the beginnings of objects can be 402 // found during scavenge. Note that we are updating the offset table based on 403 // where the object will be once the compaction phase finishes. 404 if (compact_top > cp->threshold) 405 cp->threshold = 406 cp->space->cross_threshold(compact_top - size, compact_top); 407 return compact_top; 408 } 409 410 #if INCLUDE_SERIALGC 411 412 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { 413 scan_and_forward(this, cp); 414 } 415 416 void CompactibleSpace::adjust_pointers() { 417 // Check first is there is any work to do. 418 if (used() == 0) { 419 return; // Nothing to do. 420 } 421 422 scan_and_adjust_pointers(this); 423 } 424 425 void CompactibleSpace::compact() { 426 scan_and_compact(this); 427 } 428 429 #endif // INCLUDE_SERIALGC 430 431 void Space::print_short() const { print_short_on(tty); } 432 433 void Space::print_short_on(outputStream* st) const { 434 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K, 435 (int) ((double) used() * 100 / capacity())); 436 } 437 438 void Space::print() const { print_on(tty); } 439 440 void Space::print_on(outputStream* st) const { 441 print_short_on(st); 442 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")", 443 p2i(bottom()), p2i(end())); 444 } 445 446 void ContiguousSpace::print_on(outputStream* st) const { 447 print_short_on(st); 448 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 449 p2i(bottom()), p2i(top()), p2i(end())); 450 } 451 452 void OffsetTableContigSpace::print_on(outputStream* st) const { 453 print_short_on(st); 454 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 455 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 456 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end())); 457 } 458 459 void ContiguousSpace::verify() const { 460 HeapWord* p = bottom(); 461 HeapWord* t = top(); 462 HeapWord* prev_p = NULL; 463 while (p < t) { 464 oopDesc::verify(oop(p)); 465 prev_p = p; 466 p += oop(p)->size(); 467 } 468 guarantee(p == top(), "end of last object must match end of space"); 469 if (top() != end()) { 470 guarantee(top() == block_start_const(end()-1) && 471 top() == block_start_const(top()), 472 "top should be start of unallocated block, if it exists"); 473 } 474 } 475 476 void Space::oop_iterate(OopIterateClosure* blk) { 477 ObjectToOopClosure blk2(blk); 478 object_iterate(&blk2); 479 } 480 481 bool Space::obj_is_alive(const HeapWord* p) const { 482 assert (block_is_obj(p), "The address should point to an object"); 483 return true; 484 } 485 486 void ContiguousSpace::oop_iterate(OopIterateClosure* blk) { 487 if (is_empty()) return; 488 HeapWord* obj_addr = bottom(); 489 HeapWord* t = top(); 490 // Could call objects iterate, but this is easier. 491 while (obj_addr < t) { 492 obj_addr += oop(obj_addr)->oop_iterate_size(blk); 493 } 494 } 495 496 void ContiguousSpace::object_iterate(ObjectClosure* blk) { 497 if (is_empty()) return; 498 object_iterate_from(bottom(), blk); 499 } 500 501 // For a ContiguousSpace object_iterate() and safe_object_iterate() 502 // are the same. 503 void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { 504 object_iterate(blk); 505 } 506 507 void ContiguousSpace::object_iterate_from(HeapWord* mark, ObjectClosure* blk) { 508 while (mark < top()) { 509 blk->do_object(oop(mark)); 510 mark += oop(mark)->size(); 511 } 512 } 513 514 HeapWord* 515 ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) { 516 HeapWord * limit = concurrent_iteration_safe_limit(); 517 assert(limit <= top(), "sanity check"); 518 for (HeapWord* p = bottom(); p < limit;) { 519 size_t size = blk->do_object_careful(oop(p)); 520 if (size == 0) { 521 return p; // failed at p 522 } else { 523 p += size; 524 } 525 } 526 return NULL; // all done 527 } 528 529 // Very general, slow implementation. 530 HeapWord* ContiguousSpace::block_start_const(const void* p) const { 531 assert(MemRegion(bottom(), end()).contains(p), 532 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 533 p2i(p), p2i(bottom()), p2i(end())); 534 if (p >= top()) { 535 return top(); 536 } else { 537 HeapWord* last = bottom(); 538 HeapWord* cur = last; 539 while (cur <= p) { 540 last = cur; 541 cur += oop(cur)->size(); 542 } 543 assert(oopDesc::is_oop(oop(last)), PTR_FORMAT " should be an object start", p2i(last)); 544 return last; 545 } 546 } 547 548 size_t ContiguousSpace::block_size(const HeapWord* p) const { 549 assert(MemRegion(bottom(), end()).contains(p), 550 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 551 p2i(p), p2i(bottom()), p2i(end())); 552 HeapWord* current_top = top(); 553 assert(p <= current_top, 554 "p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT, 555 p2i(p), p2i(current_top)); 556 assert(p == current_top || oopDesc::is_oop(oop(p)), 557 "p (" PTR_FORMAT ") is not a block start - " 558 "current_top: " PTR_FORMAT ", is_oop: %s", 559 p2i(p), p2i(current_top), BOOL_TO_STR(oopDesc::is_oop(oop(p)))); 560 if (p < current_top) { 561 return oop(p)->size(); 562 } else { 563 assert(p == current_top, "just checking"); 564 return pointer_delta(end(), (HeapWord*) p); 565 } 566 } 567 568 // This version requires locking. 569 inline HeapWord* ContiguousSpace::allocate_impl(size_t size) { 570 assert(Heap_lock->owned_by_self() || 571 (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), 572 "not locked"); 573 HeapWord* obj = top(); 574 if (pointer_delta(end(), obj) >= size) { 575 HeapWord* new_top = obj + size; 576 set_top(new_top); 577 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); 578 return obj; 579 } else { 580 return NULL; 581 } 582 } 583 584 // This version is lock-free. 585 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) { 586 do { 587 HeapWord* obj = top(); 588 if (pointer_delta(end(), obj) >= size) { 589 HeapWord* new_top = obj + size; 590 HeapWord* result = Atomic::cmpxchg(new_top, top_addr(), obj); 591 // result can be one of two: 592 // the old top value: the exchange succeeded 593 // otherwise: the new value of the top is returned. 594 if (result == obj) { 595 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); 596 return obj; 597 } 598 } else { 599 return NULL; 600 } 601 } while (true); 602 } 603 604 HeapWord* ContiguousSpace::allocate_aligned(size_t size) { 605 assert(Heap_lock->owned_by_self() || (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), "not locked"); 606 HeapWord* end_value = end(); 607 608 HeapWord* obj = CollectedHeap::align_allocation_or_fail(top(), end_value, SurvivorAlignmentInBytes); 609 if (obj == NULL) { 610 return NULL; 611 } 612 613 if (pointer_delta(end_value, obj) >= size) { 614 HeapWord* new_top = obj + size; 615 set_top(new_top); 616 assert(::is_aligned(obj, SurvivorAlignmentInBytes) && is_aligned(new_top), 617 "checking alignment"); 618 return obj; 619 } else { 620 set_top(obj); 621 return NULL; 622 } 623 } 624 625 // Requires locking. 626 HeapWord* ContiguousSpace::allocate(size_t size) { 627 return allocate_impl(size); 628 } 629 630 // Lock-free. 631 HeapWord* ContiguousSpace::par_allocate(size_t size) { 632 return par_allocate_impl(size); 633 } 634 635 void ContiguousSpace::allocate_temporary_filler(int factor) { 636 // allocate temporary type array decreasing free size with factor 'factor' 637 assert(factor >= 0, "just checking"); 638 size_t size = pointer_delta(end(), top()); 639 640 // if space is full, return 641 if (size == 0) return; 642 643 if (factor > 0) { 644 size -= size/factor; 645 } 646 size = align_object_size(size); 647 648 const size_t array_header_size = typeArrayOopDesc::header_size(T_INT); 649 if (size >= align_object_size(array_header_size)) { 650 size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint)); 651 // allocate uninitialized int array 652 typeArrayOop t = (typeArrayOop) allocate(size); 653 assert(t != NULL, "allocation should succeed"); 654 t->set_mark_raw(markOopDesc::prototype()); 655 t->set_klass(Universe::intArrayKlassObj()); 656 t->set_length((int)length); 657 } else { 658 assert(size == CollectedHeap::min_fill_size(), 659 "size for smallest fake object doesn't match"); 660 instanceOop obj = (instanceOop) allocate(size); 661 obj->set_mark_raw(markOopDesc::prototype()); 662 obj->set_klass_gap(0); 663 obj->set_klass(SystemDictionary::Object_klass()); 664 } 665 } 666 667 HeapWord* OffsetTableContigSpace::initialize_threshold() { 668 return _offsets.initialize_threshold(); 669 } 670 671 HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) { 672 _offsets.alloc_block(start, end); 673 return _offsets.threshold(); 674 } 675 676 OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, 677 MemRegion mr) : 678 _offsets(sharedOffsetArray, mr), 679 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true) 680 { 681 _offsets.set_contig_space(this); 682 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); 683 } 684 685 #define OBJ_SAMPLE_INTERVAL 0 686 #define BLOCK_SAMPLE_INTERVAL 100 687 688 void OffsetTableContigSpace::verify() const { 689 HeapWord* p = bottom(); 690 HeapWord* prev_p = NULL; 691 int objs = 0; 692 int blocks = 0; 693 694 if (VerifyObjectStartArray) { 695 _offsets.verify(); 696 } 697 698 while (p < top()) { 699 size_t size = oop(p)->size(); 700 // For a sampling of objects in the space, find it using the 701 // block offset table. 702 if (blocks == BLOCK_SAMPLE_INTERVAL) { 703 guarantee(p == block_start_const(p + (size/2)), 704 "check offset computation"); 705 blocks = 0; 706 } else { 707 blocks++; 708 } 709 710 if (objs == OBJ_SAMPLE_INTERVAL) { 711 oopDesc::verify(oop(p)); 712 objs = 0; 713 } else { 714 objs++; 715 } 716 prev_p = p; 717 p += size; 718 } 719 guarantee(p == top(), "end of last object must match end of space"); 720 } 721 722 723 size_t TenuredSpace::allowed_dead_ratio() const { 724 return MarkSweepDeadRatio; 725 }