1 /* 2 * Copyright (c) 1997, 2015, 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/serial/defNewGeneration.hpp" 29 #include "gc/shared/blockOffsetTable.inline.hpp" 30 #include "gc/shared/collectedHeap.inline.hpp" 31 #include "gc/shared/genCollectedHeap.hpp" 32 #include "gc/shared/genOopClosures.inline.hpp" 33 #include "gc/shared/liveRange.hpp" 34 #include "gc/shared/space.hpp" 35 #include "gc/shared/space.inline.hpp" 36 #include "gc/shared/spaceDecorator.hpp" 37 #include "memory/universe.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "runtime/atomic.inline.hpp" 40 #include "runtime/java.hpp" 41 #include "runtime/orderAccess.inline.hpp" 42 #include "runtime/prefetch.inline.hpp" 43 #include "runtime/safepoint.hpp" 44 #include "utilities/copy.hpp" 45 #include "utilities/globalDefinitions.hpp" 46 #include "utilities/macros.hpp" 47 48 HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top, 49 HeapWord* top_obj) { 50 if (top_obj != NULL) { 51 if (_sp->block_is_obj(top_obj)) { 52 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { 53 if (oop(top_obj)->is_objArray() || 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 // Use the block_size() method of the space over which 61 // the iteration is being done. That space (e.g. CMS) may have 62 // specific requirements on object sizes which will 63 // be reflected in the block_size() method. 64 top = top_obj + oop(top_obj)->size(); 65 } 66 } 67 } else { 68 top = top_obj; 69 } 70 } else { 71 assert(top == _sp->end(), "only case where top_obj == NULL"); 72 } 73 return top; 74 } 75 76 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr, 77 HeapWord* bottom, 78 HeapWord* top) { 79 // 1. Blocks may or may not be objects. 80 // 2. Even when a block_is_obj(), it may not entirely 81 // occupy the block if the block quantum is larger than 82 // the object size. 83 // We can and should try to optimize by calling the non-MemRegion 84 // version of oop_iterate() for all but the extremal objects 85 // (for which we need to call the MemRegion version of 86 // oop_iterate()) To be done post-beta XXX 87 for (; bottom < top; bottom += _sp->block_size(bottom)) { 88 // As in the case of contiguous space above, we'd like to 89 // just use the value returned by oop_iterate to increment the 90 // current pointer; unfortunately, that won't work in CMS because 91 // we'd need an interface change (it seems) to have the space 92 // "adjust the object size" (for instance pad it up to its 93 // block alignment or minimum block size restrictions. XXX 94 if (_sp->block_is_obj(bottom) && 95 !_sp->obj_allocated_since_save_marks(oop(bottom))) { 96 oop(bottom)->oop_iterate(_cl, mr); 97 } 98 } 99 } 100 101 // We get called with "mr" representing the dirty region 102 // that we want to process. Because of imprecise marking, 103 // we may need to extend the incoming "mr" to the right, 104 // and scan more. However, because we may already have 105 // scanned some of that extended region, we may need to 106 // trim its right-end back some so we do not scan what 107 // we (or another worker thread) may already have scanned 108 // or planning to scan. 109 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) { 110 111 // Some collectors need to do special things whenever their dirty 112 // cards are processed. For instance, CMS must remember mutator updates 113 // (i.e. dirty cards) so as to re-scan mutated objects. 114 // Such work can be piggy-backed here on dirty card scanning, so as to make 115 // it slightly more efficient than doing a complete non-destructive pre-scan 116 // of the card table. 117 MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure(); 118 if (pCl != NULL) { 119 pCl->do_MemRegion(mr); 120 } 121 122 HeapWord* bottom = mr.start(); 123 HeapWord* last = mr.last(); 124 HeapWord* top = mr.end(); 125 HeapWord* bottom_obj; 126 HeapWord* top_obj; 127 128 assert(_precision == CardTableModRefBS::ObjHeadPreciseArray || 129 _precision == CardTableModRefBS::Precise, 130 "Only ones we deal with for now."); 131 132 assert(_precision != CardTableModRefBS::ObjHeadPreciseArray || 133 _cl->idempotent() || _last_bottom == NULL || 134 top <= _last_bottom, 135 "Not decreasing"); 136 NOT_PRODUCT(_last_bottom = mr.start()); 137 138 bottom_obj = _sp->block_start(bottom); 139 top_obj = _sp->block_start(last); 140 141 assert(bottom_obj <= bottom, "just checking"); 142 assert(top_obj <= top, "just checking"); 143 144 // Given what we think is the top of the memory region and 145 // the start of the object at the top, get the actual 146 // value of the top. 147 top = get_actual_top(top, top_obj); 148 149 // If the previous call did some part of this region, don't redo. 150 if (_precision == CardTableModRefBS::ObjHeadPreciseArray && 151 _min_done != NULL && 152 _min_done < top) { 153 top = _min_done; 154 } 155 156 // Top may have been reset, and in fact may be below bottom, 157 // e.g. the dirty card region is entirely in a now free object 158 // -- something that could happen with a concurrent sweeper. 159 bottom = MIN2(bottom, top); 160 MemRegion extended_mr = MemRegion(bottom, top); 161 assert(bottom <= top && 162 (_precision != CardTableModRefBS::ObjHeadPreciseArray || 163 _min_done == NULL || 164 top <= _min_done), 165 "overlap!"); 166 167 // Walk the region if it is not empty; otherwise there is nothing to do. 168 if (!extended_mr.is_empty()) { 169 walk_mem_region(extended_mr, bottom_obj, top); 170 } 171 172 // An idempotent closure might be applied in any order, so we don't 173 // record a _min_done for it. 174 if (!_cl->idempotent()) { 175 _min_done = bottom; 176 } else { 177 assert(_min_done == _last_explicit_min_done, 178 "Don't update _min_done for idempotent cl"); 179 } 180 } 181 182 DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl, 183 CardTableModRefBS::PrecisionStyle precision, 184 HeapWord* boundary, 185 bool parallel) { 186 return new DirtyCardToOopClosure(this, cl, precision, boundary); 187 } 188 189 HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top, 190 HeapWord* top_obj) { 191 if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) { 192 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { 193 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { 194 // An arrayOop is starting on the dirty card - since we do exact 195 // store checks for objArrays we are done. 196 } else { 197 // Otherwise, it is possible that the object starting on the dirty 198 // card spans the entire card, and that the store happened on a 199 // later card. Figure out where the object ends. 200 assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(), 201 "Block size and object size mismatch"); 202 top = top_obj + oop(top_obj)->size(); 203 } 204 } 205 } else { 206 top = (_sp->toContiguousSpace())->top(); 207 } 208 return top; 209 } 210 211 void FilteringDCTOC::walk_mem_region(MemRegion mr, 212 HeapWord* bottom, 213 HeapWord* top) { 214 // Note that this assumption won't hold if we have a concurrent 215 // collector in this space, which may have freed up objects after 216 // they were dirtied and before the stop-the-world GC that is 217 // examining cards here. 218 assert(bottom < top, "ought to be at least one obj on a dirty card."); 219 220 if (_boundary != NULL) { 221 // We have a boundary outside of which we don't want to look 222 // at objects, so create a filtering closure around the 223 // oop closure before walking the region. 224 FilteringClosure filter(_boundary, _cl); 225 walk_mem_region_with_cl(mr, bottom, top, &filter); 226 } else { 227 // No boundary, simply walk the heap with the oop closure. 228 walk_mem_region_with_cl(mr, bottom, top, _cl); 229 } 230 231 } 232 233 // We must replicate this so that the static type of "FilteringClosure" 234 // (see above) is apparent at the oop_iterate calls. 235 #define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ 236 void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \ 237 HeapWord* bottom, \ 238 HeapWord* top, \ 239 ClosureType* cl) { \ 240 bottom += oop(bottom)->oop_iterate_size(cl, mr); \ 241 if (bottom < top) { \ 242 HeapWord* next_obj = bottom + oop(bottom)->size(); \ 243 while (next_obj < top) { \ 244 /* Bottom lies entirely below top, so we can call the */ \ 245 /* non-memRegion version of oop_iterate below. */ \ 246 oop(bottom)->oop_iterate(cl); \ 247 bottom = next_obj; \ 248 next_obj = bottom + oop(bottom)->size(); \ 249 } \ 250 /* Last object. */ \ 251 oop(bottom)->oop_iterate(cl, mr); \ 252 } \ 253 } 254 255 // (There are only two of these, rather than N, because the split is due 256 // only to the introduction of the FilteringClosure, a local part of the 257 // impl of this abstraction.) 258 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure) 259 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) 260 261 DirtyCardToOopClosure* 262 ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl, 263 CardTableModRefBS::PrecisionStyle precision, 264 HeapWord* boundary, 265 bool parallel) { 266 return new ContiguousSpaceDCTOC(this, cl, precision, boundary); 267 } 268 269 void Space::initialize(MemRegion mr, 270 bool clear_space, 271 bool mangle_space) { 272 HeapWord* bottom = mr.start(); 273 HeapWord* end = mr.end(); 274 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end), 275 "invalid space boundaries"); 276 set_bottom(bottom); 277 set_end(end); 278 if (clear_space) clear(mangle_space); 279 } 280 281 void Space::clear(bool mangle_space) { 282 if (ZapUnusedHeapArea && mangle_space) { 283 mangle_unused_area(); 284 } 285 } 286 287 ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL), 288 _concurrent_iteration_safe_limit(NULL) { 289 _mangler = new GenSpaceMangler(this); 290 } 291 292 ContiguousSpace::~ContiguousSpace() { 293 delete _mangler; 294 } 295 296 void ContiguousSpace::initialize(MemRegion mr, 297 bool clear_space, 298 bool mangle_space) 299 { 300 CompactibleSpace::initialize(mr, clear_space, mangle_space); 301 set_concurrent_iteration_safe_limit(top()); 302 } 303 304 void ContiguousSpace::clear(bool mangle_space) { 305 set_top(bottom()); 306 set_saved_mark(); 307 CompactibleSpace::clear(mangle_space); 308 } 309 310 bool ContiguousSpace::is_free_block(const HeapWord* p) const { 311 return p >= _top; 312 } 313 314 void OffsetTableContigSpace::clear(bool mangle_space) { 315 ContiguousSpace::clear(mangle_space); 316 _offsets.initialize_threshold(); 317 } 318 319 void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 320 Space::set_bottom(new_bottom); 321 _offsets.set_bottom(new_bottom); 322 } 323 324 void OffsetTableContigSpace::set_end(HeapWord* new_end) { 325 // Space should not advertise an increase in size 326 // until after the underlying offset table has been enlarged. 327 _offsets.resize(pointer_delta(new_end, bottom())); 328 Space::set_end(new_end); 329 } 330 331 #ifndef PRODUCT 332 333 void ContiguousSpace::set_top_for_allocations(HeapWord* v) { 334 mangler()->set_top_for_allocations(v); 335 } 336 void ContiguousSpace::set_top_for_allocations() { 337 mangler()->set_top_for_allocations(top()); 338 } 339 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) { 340 mangler()->check_mangled_unused_area(limit); 341 } 342 343 void ContiguousSpace::check_mangled_unused_area_complete() { 344 mangler()->check_mangled_unused_area_complete(); 345 } 346 347 // Mangled only the unused space that has not previously 348 // been mangled and that has not been allocated since being 349 // mangled. 350 void ContiguousSpace::mangle_unused_area() { 351 mangler()->mangle_unused_area(); 352 } 353 void ContiguousSpace::mangle_unused_area_complete() { 354 mangler()->mangle_unused_area_complete(); 355 } 356 #endif // NOT_PRODUCT 357 358 void CompactibleSpace::initialize(MemRegion mr, 359 bool clear_space, 360 bool mangle_space) { 361 Space::initialize(mr, clear_space, mangle_space); 362 set_compaction_top(bottom()); 363 _next_compaction_space = NULL; 364 } 365 366 void CompactibleSpace::clear(bool mangle_space) { 367 Space::clear(mangle_space); 368 _compaction_top = bottom(); 369 } 370 371 HeapWord* CompactibleSpace::forward(oop q, size_t size, 372 CompactPoint* cp, HeapWord* compact_top) { 373 // q is alive 374 // First check if we should switch compaction space 375 assert(this == cp->space, "'this' should be current compaction space."); 376 size_t compaction_max_size = pointer_delta(end(), compact_top); 377 while (size > compaction_max_size) { 378 // switch to next compaction space 379 cp->space->set_compaction_top(compact_top); 380 cp->space = cp->space->next_compaction_space(); 381 if (cp->space == NULL) { 382 cp->gen = GenCollectedHeap::heap()->young_gen(); 383 assert(cp->gen != NULL, "compaction must succeed"); 384 cp->space = cp->gen->first_compaction_space(); 385 assert(cp->space != NULL, "generation must have a first compaction space"); 386 } 387 compact_top = cp->space->bottom(); 388 cp->space->set_compaction_top(compact_top); 389 cp->threshold = cp->space->initialize_threshold(); 390 compaction_max_size = pointer_delta(cp->space->end(), compact_top); 391 } 392 393 // store the forwarding pointer into the mark word 394 if ((HeapWord*)q != compact_top) { 395 q->forward_to(oop(compact_top)); 396 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); 397 } else { 398 // if the object isn't moving we can just set the mark to the default 399 // mark and handle it specially later on. 400 q->init_mark(); 401 assert(q->forwardee() == NULL, "should be forwarded to NULL"); 402 } 403 404 compact_top += size; 405 406 // we need to update the offset table so that the beginnings of objects can be 407 // found during scavenge. Note that we are updating the offset table based on 408 // where the object will be once the compaction phase finishes. 409 if (compact_top > cp->threshold) 410 cp->threshold = 411 cp->space->cross_threshold(compact_top - size, compact_top); 412 return compact_top; 413 } 414 415 416 bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words, 417 HeapWord* q, size_t deadlength) { 418 if (allowed_deadspace_words >= deadlength) { 419 allowed_deadspace_words -= deadlength; 420 CollectedHeap::fill_with_object(q, deadlength); 421 oop(q)->set_mark(oop(q)->mark()->set_marked()); 422 assert((int) deadlength == oop(q)->size(), "bad filler object size"); 423 // Recall that we required "q == compaction_top". 424 return true; 425 } else { 426 allowed_deadspace_words = 0; 427 return false; 428 } 429 } 430 431 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { 432 scan_and_forward(this, cp); 433 } 434 435 void CompactibleSpace::adjust_pointers() { 436 // Check first is there is any work to do. 437 if (used() == 0) { 438 return; // Nothing to do. 439 } 440 441 scan_and_adjust_pointers(this); 442 } 443 444 void CompactibleSpace::compact() { 445 scan_and_compact(this); 446 } 447 448 void Space::print_short() const { print_short_on(tty); } 449 450 void Space::print_short_on(outputStream* st) const { 451 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K, 452 (int) ((double) used() * 100 / capacity())); 453 } 454 455 void Space::print() const { print_on(tty); } 456 457 void Space::print_on(outputStream* st) const { 458 print_short_on(st); 459 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")", 460 p2i(bottom()), p2i(end())); 461 } 462 463 void ContiguousSpace::print_on(outputStream* st) const { 464 print_short_on(st); 465 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 466 p2i(bottom()), p2i(top()), p2i(end())); 467 } 468 469 void OffsetTableContigSpace::print_on(outputStream* st) const { 470 print_short_on(st); 471 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 472 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 473 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end())); 474 } 475 476 void ContiguousSpace::verify() const { 477 HeapWord* p = bottom(); 478 HeapWord* t = top(); 479 HeapWord* prev_p = NULL; 480 while (p < t) { 481 oop(p)->verify(); 482 prev_p = p; 483 p += oop(p)->size(); 484 } 485 guarantee(p == top(), "end of last object must match end of space"); 486 if (top() != end()) { 487 guarantee(top() == block_start_const(end()-1) && 488 top() == block_start_const(top()), 489 "top should be start of unallocated block, if it exists"); 490 } 491 } 492 493 void Space::oop_iterate(ExtendedOopClosure* blk) { 494 ObjectToOopClosure blk2(blk); 495 object_iterate(&blk2); 496 } 497 498 bool Space::obj_is_alive(const HeapWord* p) const { 499 assert (block_is_obj(p), "The address should point to an object"); 500 return true; 501 } 502 503 #if INCLUDE_ALL_GCS 504 #define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ 505 \ 506 void ContiguousSpace::par_oop_iterate(MemRegion mr, OopClosureType* blk) {\ 507 HeapWord* obj_addr = mr.start(); \ 508 HeapWord* t = mr.end(); \ 509 while (obj_addr < t) { \ 510 assert(oop(obj_addr)->is_oop(), "Should be an oop"); \ 511 obj_addr += oop(obj_addr)->oop_iterate_size(blk); \ 512 } \ 513 } 514 515 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DEFN) 516 517 #undef ContigSpace_PAR_OOP_ITERATE_DEFN 518 #endif // INCLUDE_ALL_GCS 519 520 void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) { 521 if (is_empty()) return; 522 HeapWord* obj_addr = bottom(); 523 HeapWord* t = top(); 524 // Could call objects iterate, but this is easier. 525 while (obj_addr < t) { 526 obj_addr += oop(obj_addr)->oop_iterate_size(blk); 527 } 528 } 529 530 void ContiguousSpace::object_iterate(ObjectClosure* blk) { 531 if (is_empty()) return; 532 object_iterate_from(bottom(), blk); 533 } 534 535 // For a ContiguousSpace object_iterate() and safe_object_iterate() 536 // are the same. 537 void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { 538 object_iterate(blk); 539 } 540 541 void ContiguousSpace::object_iterate_from(HeapWord* mark, ObjectClosure* blk) { 542 while (mark < top()) { 543 blk->do_object(oop(mark)); 544 mark += oop(mark)->size(); 545 } 546 } 547 548 HeapWord* 549 ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) { 550 HeapWord * limit = concurrent_iteration_safe_limit(); 551 assert(limit <= top(), "sanity check"); 552 for (HeapWord* p = bottom(); p < limit;) { 553 size_t size = blk->do_object_careful(oop(p)); 554 if (size == 0) { 555 return p; // failed at p 556 } else { 557 p += size; 558 } 559 } 560 return NULL; // all done 561 } 562 563 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ 564 \ 565 void ContiguousSpace:: \ 566 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ 567 HeapWord* t; \ 568 HeapWord* p = saved_mark_word(); \ 569 assert(p != NULL, "expected saved mark"); \ 570 \ 571 const intx interval = PrefetchScanIntervalInBytes; \ 572 do { \ 573 t = top(); \ 574 while (p < t) { \ 575 Prefetch::write(p, interval); \ 576 debug_only(HeapWord* prev = p); \ 577 oop m = oop(p); \ 578 p += m->oop_iterate_size(blk); \ 579 } \ 580 } while (t < top()); \ 581 \ 582 set_saved_mark_word(p); \ 583 } 584 585 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN) 586 587 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN 588 589 // Very general, slow implementation. 590 HeapWord* ContiguousSpace::block_start_const(const void* p) const { 591 assert(MemRegion(bottom(), end()).contains(p), 592 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 593 p2i(p), p2i(bottom()), p2i(end())); 594 if (p >= top()) { 595 return top(); 596 } else { 597 HeapWord* last = bottom(); 598 HeapWord* cur = last; 599 while (cur <= p) { 600 last = cur; 601 cur += oop(cur)->size(); 602 } 603 assert(oop(last)->is_oop(), PTR_FORMAT " should be an object start", p2i(last)); 604 return last; 605 } 606 } 607 608 size_t ContiguousSpace::block_size(const HeapWord* p) const { 609 assert(MemRegion(bottom(), end()).contains(p), 610 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 611 p2i(p), p2i(bottom()), p2i(end())); 612 HeapWord* current_top = top(); 613 assert(p <= current_top, 614 "p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT, 615 p2i(p), p2i(current_top)); 616 assert(p == current_top || oop(p)->is_oop(), 617 "p (" PTR_FORMAT ") is not a block start - " 618 "current_top: " PTR_FORMAT ", is_oop: %s", 619 p2i(p), p2i(current_top), BOOL_TO_STR(oop(p)->is_oop())); 620 if (p < current_top) { 621 return oop(p)->size(); 622 } else { 623 assert(p == current_top, "just checking"); 624 return pointer_delta(end(), (HeapWord*) p); 625 } 626 } 627 628 // This version requires locking. 629 inline HeapWord* ContiguousSpace::allocate_impl(size_t size) { 630 assert(Heap_lock->owned_by_self() || 631 (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), 632 "not locked"); 633 HeapWord* obj = top(); 634 if (pointer_delta(end(), obj) >= size) { 635 HeapWord* new_top = obj + size; 636 set_top(new_top); 637 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); 638 return obj; 639 } else { 640 return NULL; 641 } 642 } 643 644 // This version is lock-free. 645 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) { 646 do { 647 HeapWord* obj = top(); 648 if (pointer_delta(end(), obj) >= size) { 649 HeapWord* new_top = obj + size; 650 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); 651 // result can be one of two: 652 // the old top value: the exchange succeeded 653 // otherwise: the new value of the top is returned. 654 if (result == obj) { 655 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); 656 return obj; 657 } 658 } else { 659 return NULL; 660 } 661 } while (true); 662 } 663 664 HeapWord* ContiguousSpace::allocate_aligned(size_t size) { 665 assert(Heap_lock->owned_by_self() || (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), "not locked"); 666 HeapWord* end_value = end(); 667 668 HeapWord* obj = CollectedHeap::align_allocation_or_fail(top(), end_value, SurvivorAlignmentInBytes); 669 if (obj == NULL) { 670 return NULL; 671 } 672 673 if (pointer_delta(end_value, obj) >= size) { 674 HeapWord* new_top = obj + size; 675 set_top(new_top); 676 assert(is_ptr_aligned(obj, SurvivorAlignmentInBytes) && is_aligned(new_top), 677 "checking alignment"); 678 return obj; 679 } else { 680 set_top(obj); 681 return NULL; 682 } 683 } 684 685 // Requires locking. 686 HeapWord* ContiguousSpace::allocate(size_t size) { 687 return allocate_impl(size); 688 } 689 690 // Lock-free. 691 HeapWord* ContiguousSpace::par_allocate(size_t size) { 692 return par_allocate_impl(size); 693 } 694 695 void ContiguousSpace::allocate_temporary_filler(int factor) { 696 // allocate temporary type array decreasing free size with factor 'factor' 697 assert(factor >= 0, "just checking"); 698 size_t size = pointer_delta(end(), top()); 699 700 // if space is full, return 701 if (size == 0) return; 702 703 if (factor > 0) { 704 size -= size/factor; 705 } 706 size = align_object_size(size); 707 708 const size_t array_header_size = typeArrayOopDesc::header_size(T_INT); 709 if (size >= (size_t)align_object_size(array_header_size)) { 710 size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint)); 711 // allocate uninitialized int array 712 typeArrayOop t = (typeArrayOop) allocate(size); 713 assert(t != NULL, "allocation should succeed"); 714 t->set_mark(markOopDesc::prototype()); 715 t->set_klass(Universe::intArrayKlassObj()); 716 t->set_length((int)length); 717 } else { 718 assert(size == CollectedHeap::min_fill_size(), 719 "size for smallest fake object doesn't match"); 720 instanceOop obj = (instanceOop) allocate(size); 721 obj->set_mark(markOopDesc::prototype()); 722 obj->set_klass_gap(0); 723 obj->set_klass(SystemDictionary::Object_klass()); 724 } 725 } 726 727 HeapWord* OffsetTableContigSpace::initialize_threshold() { 728 return _offsets.initialize_threshold(); 729 } 730 731 HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) { 732 _offsets.alloc_block(start, end); 733 return _offsets.threshold(); 734 } 735 736 OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, 737 MemRegion mr) : 738 _offsets(sharedOffsetArray, mr), 739 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true) 740 { 741 _offsets.set_contig_space(this); 742 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); 743 } 744 745 #define OBJ_SAMPLE_INTERVAL 0 746 #define BLOCK_SAMPLE_INTERVAL 100 747 748 void OffsetTableContigSpace::verify() const { 749 HeapWord* p = bottom(); 750 HeapWord* prev_p = NULL; 751 int objs = 0; 752 int blocks = 0; 753 754 if (VerifyObjectStartArray) { 755 _offsets.verify(); 756 } 757 758 while (p < top()) { 759 size_t size = oop(p)->size(); 760 // For a sampling of objects in the space, find it using the 761 // block offset table. 762 if (blocks == BLOCK_SAMPLE_INTERVAL) { 763 guarantee(p == block_start_const(p + (size/2)), 764 "check offset computation"); 765 blocks = 0; 766 } else { 767 blocks++; 768 } 769 770 if (objs == OBJ_SAMPLE_INTERVAL) { 771 oop(p)->verify(); 772 objs = 0; 773 } else { 774 objs++; 775 } 776 prev_p = p; 777 p += size; 778 } 779 guarantee(p == top(), "end of last object must match end of space"); 780 } 781 782 783 size_t TenuredSpace::allowed_dead_ratio() const { 784 return MarkSweepDeadRatio; 785 }