src/share/vm/memory/space.cpp

Tue, 29 Apr 2014 15:17:27 +0200

author
goetz
date
Tue, 29 Apr 2014 15:17:27 +0200
changeset 6911
ce8f6bb717c9
parent 6680
78bbf4d43a14
child 6912
c49dcaf78a65
permissions
-rw-r--r--

8042195: Introduce umbrella header orderAccess.inline.hpp.
Reviewed-by: dholmes, kvn, stefank, twisti

duke@435 1 /*
drchase@6680 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
trims@1907 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907 20 * or visit www.oracle.com if you need additional information or have any
trims@1907 21 * questions.
duke@435 22 *
duke@435 23 */
duke@435 24
stefank@2314 25 #include "precompiled.hpp"
stefank@2314 26 #include "classfile/systemDictionary.hpp"
stefank@2314 27 #include "classfile/vmSymbols.hpp"
stefank@2314 28 #include "gc_implementation/shared/liveRange.hpp"
stefank@2314 29 #include "gc_implementation/shared/markSweep.hpp"
stefank@2314 30 #include "gc_implementation/shared/spaceDecorator.hpp"
stefank@2314 31 #include "memory/blockOffsetTable.inline.hpp"
stefank@2314 32 #include "memory/defNewGeneration.hpp"
stefank@2314 33 #include "memory/genCollectedHeap.hpp"
stefank@2314 34 #include "memory/space.hpp"
stefank@2314 35 #include "memory/space.inline.hpp"
stefank@2314 36 #include "memory/universe.inline.hpp"
stefank@2314 37 #include "oops/oop.inline.hpp"
stefank@2314 38 #include "oops/oop.inline2.hpp"
stefank@2314 39 #include "runtime/java.hpp"
goetz@6911 40 #include "runtime/orderAccess.inline.hpp"
stefank@2314 41 #include "runtime/safepoint.hpp"
stefank@2314 42 #include "utilities/copy.hpp"
stefank@2314 43 #include "utilities/globalDefinitions.hpp"
jprovino@4542 44 #include "utilities/macros.hpp"
duke@435 45
coleenp@548 46 void SpaceMemRegionOopsIterClosure::do_oop(oop* p) { SpaceMemRegionOopsIterClosure::do_oop_work(p); }
coleenp@548 47 void SpaceMemRegionOopsIterClosure::do_oop(narrowOop* p) { SpaceMemRegionOopsIterClosure::do_oop_work(p); }
coleenp@548 48
drchase@6680 49 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
drchase@6680 50
duke@435 51 HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top,
duke@435 52 HeapWord* top_obj) {
duke@435 53 if (top_obj != NULL) {
duke@435 54 if (_sp->block_is_obj(top_obj)) {
duke@435 55 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) {
duke@435 56 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
duke@435 57 // An arrayOop is starting on the dirty card - since we do exact
duke@435 58 // store checks for objArrays we are done.
duke@435 59 } else {
duke@435 60 // Otherwise, it is possible that the object starting on the dirty
duke@435 61 // card spans the entire card, and that the store happened on a
duke@435 62 // later card. Figure out where the object ends.
duke@435 63 // Use the block_size() method of the space over which
duke@435 64 // the iteration is being done. That space (e.g. CMS) may have
duke@435 65 // specific requirements on object sizes which will
duke@435 66 // be reflected in the block_size() method.
duke@435 67 top = top_obj + oop(top_obj)->size();
duke@435 68 }
duke@435 69 }
duke@435 70 } else {
duke@435 71 top = top_obj;
duke@435 72 }
duke@435 73 } else {
duke@435 74 assert(top == _sp->end(), "only case where top_obj == NULL");
duke@435 75 }
duke@435 76 return top;
duke@435 77 }
duke@435 78
duke@435 79 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr,
duke@435 80 HeapWord* bottom,
duke@435 81 HeapWord* top) {
duke@435 82 // 1. Blocks may or may not be objects.
duke@435 83 // 2. Even when a block_is_obj(), it may not entirely
duke@435 84 // occupy the block if the block quantum is larger than
duke@435 85 // the object size.
duke@435 86 // We can and should try to optimize by calling the non-MemRegion
duke@435 87 // version of oop_iterate() for all but the extremal objects
duke@435 88 // (for which we need to call the MemRegion version of
duke@435 89 // oop_iterate()) To be done post-beta XXX
duke@435 90 for (; bottom < top; bottom += _sp->block_size(bottom)) {
duke@435 91 // As in the case of contiguous space above, we'd like to
duke@435 92 // just use the value returned by oop_iterate to increment the
duke@435 93 // current pointer; unfortunately, that won't work in CMS because
duke@435 94 // we'd need an interface change (it seems) to have the space
duke@435 95 // "adjust the object size" (for instance pad it up to its
duke@435 96 // block alignment or minimum block size restrictions. XXX
duke@435 97 if (_sp->block_is_obj(bottom) &&
duke@435 98 !_sp->obj_allocated_since_save_marks(oop(bottom))) {
duke@435 99 oop(bottom)->oop_iterate(_cl, mr);
duke@435 100 }
duke@435 101 }
duke@435 102 }
duke@435 103
ysr@2889 104 // We get called with "mr" representing the dirty region
ysr@2889 105 // that we want to process. Because of imprecise marking,
ysr@2889 106 // we may need to extend the incoming "mr" to the right,
ysr@2889 107 // and scan more. However, because we may already have
ysr@2889 108 // scanned some of that extended region, we may need to
ysr@2889 109 // trim its right-end back some so we do not scan what
ysr@2889 110 // we (or another worker thread) may already have scanned
ysr@2889 111 // or planning to scan.
duke@435 112 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) {
duke@435 113
duke@435 114 // Some collectors need to do special things whenever their dirty
duke@435 115 // cards are processed. For instance, CMS must remember mutator updates
duke@435 116 // (i.e. dirty cards) so as to re-scan mutated objects.
duke@435 117 // Such work can be piggy-backed here on dirty card scanning, so as to make
duke@435 118 // it slightly more efficient than doing a complete non-detructive pre-scan
duke@435 119 // of the card table.
duke@435 120 MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure();
duke@435 121 if (pCl != NULL) {
duke@435 122 pCl->do_MemRegion(mr);
duke@435 123 }
duke@435 124
duke@435 125 HeapWord* bottom = mr.start();
duke@435 126 HeapWord* last = mr.last();
duke@435 127 HeapWord* top = mr.end();
duke@435 128 HeapWord* bottom_obj;
duke@435 129 HeapWord* top_obj;
duke@435 130
duke@435 131 assert(_precision == CardTableModRefBS::ObjHeadPreciseArray ||
duke@435 132 _precision == CardTableModRefBS::Precise,
duke@435 133 "Only ones we deal with for now.");
duke@435 134
duke@435 135 assert(_precision != CardTableModRefBS::ObjHeadPreciseArray ||
ysr@777 136 _cl->idempotent() || _last_bottom == NULL ||
duke@435 137 top <= _last_bottom,
duke@435 138 "Not decreasing");
duke@435 139 NOT_PRODUCT(_last_bottom = mr.start());
duke@435 140
duke@435 141 bottom_obj = _sp->block_start(bottom);
duke@435 142 top_obj = _sp->block_start(last);
duke@435 143
duke@435 144 assert(bottom_obj <= bottom, "just checking");
duke@435 145 assert(top_obj <= top, "just checking");
duke@435 146
duke@435 147 // Given what we think is the top of the memory region and
duke@435 148 // the start of the object at the top, get the actual
duke@435 149 // value of the top.
duke@435 150 top = get_actual_top(top, top_obj);
duke@435 151
duke@435 152 // If the previous call did some part of this region, don't redo.
duke@435 153 if (_precision == CardTableModRefBS::ObjHeadPreciseArray &&
duke@435 154 _min_done != NULL &&
duke@435 155 _min_done < top) {
duke@435 156 top = _min_done;
duke@435 157 }
duke@435 158
duke@435 159 // Top may have been reset, and in fact may be below bottom,
duke@435 160 // e.g. the dirty card region is entirely in a now free object
duke@435 161 // -- something that could happen with a concurrent sweeper.
duke@435 162 bottom = MIN2(bottom, top);
ysr@2889 163 MemRegion extended_mr = MemRegion(bottom, top);
duke@435 164 assert(bottom <= top &&
duke@435 165 (_precision != CardTableModRefBS::ObjHeadPreciseArray ||
duke@435 166 _min_done == NULL ||
duke@435 167 top <= _min_done),
duke@435 168 "overlap!");
duke@435 169
duke@435 170 // Walk the region if it is not empty; otherwise there is nothing to do.
ysr@2889 171 if (!extended_mr.is_empty()) {
ysr@2889 172 walk_mem_region(extended_mr, bottom_obj, top);
duke@435 173 }
duke@435 174
ysr@777 175 // An idempotent closure might be applied in any order, so we don't
ysr@777 176 // record a _min_done for it.
ysr@777 177 if (!_cl->idempotent()) {
ysr@777 178 _min_done = bottom;
ysr@777 179 } else {
ysr@777 180 assert(_min_done == _last_explicit_min_done,
ysr@777 181 "Don't update _min_done for idempotent cl");
ysr@777 182 }
duke@435 183 }
duke@435 184
coleenp@4037 185 DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl,
duke@435 186 CardTableModRefBS::PrecisionStyle precision,
duke@435 187 HeapWord* boundary) {
duke@435 188 return new DirtyCardToOopClosure(this, cl, precision, boundary);
duke@435 189 }
duke@435 190
duke@435 191 HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top,
duke@435 192 HeapWord* top_obj) {
duke@435 193 if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) {
duke@435 194 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) {
duke@435 195 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
duke@435 196 // An arrayOop is starting on the dirty card - since we do exact
duke@435 197 // store checks for objArrays we are done.
duke@435 198 } else {
duke@435 199 // Otherwise, it is possible that the object starting on the dirty
duke@435 200 // card spans the entire card, and that the store happened on a
duke@435 201 // later card. Figure out where the object ends.
duke@435 202 assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(),
duke@435 203 "Block size and object size mismatch");
duke@435 204 top = top_obj + oop(top_obj)->size();
duke@435 205 }
duke@435 206 }
duke@435 207 } else {
duke@435 208 top = (_sp->toContiguousSpace())->top();
duke@435 209 }
duke@435 210 return top;
duke@435 211 }
duke@435 212
duke@435 213 void Filtering_DCTOC::walk_mem_region(MemRegion mr,
duke@435 214 HeapWord* bottom,
duke@435 215 HeapWord* top) {
duke@435 216 // Note that this assumption won't hold if we have a concurrent
duke@435 217 // collector in this space, which may have freed up objects after
duke@435 218 // they were dirtied and before the stop-the-world GC that is
duke@435 219 // examining cards here.
duke@435 220 assert(bottom < top, "ought to be at least one obj on a dirty card.");
duke@435 221
duke@435 222 if (_boundary != NULL) {
duke@435 223 // We have a boundary outside of which we don't want to look
duke@435 224 // at objects, so create a filtering closure around the
duke@435 225 // oop closure before walking the region.
duke@435 226 FilteringClosure filter(_boundary, _cl);
duke@435 227 walk_mem_region_with_cl(mr, bottom, top, &filter);
duke@435 228 } else {
duke@435 229 // No boundary, simply walk the heap with the oop closure.
duke@435 230 walk_mem_region_with_cl(mr, bottom, top, _cl);
duke@435 231 }
duke@435 232
duke@435 233 }
duke@435 234
duke@435 235 // We must replicate this so that the static type of "FilteringClosure"
duke@435 236 // (see above) is apparent at the oop_iterate calls.
duke@435 237 #define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \
duke@435 238 void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \
duke@435 239 HeapWord* bottom, \
duke@435 240 HeapWord* top, \
duke@435 241 ClosureType* cl) { \
duke@435 242 bottom += oop(bottom)->oop_iterate(cl, mr); \
duke@435 243 if (bottom < top) { \
duke@435 244 HeapWord* next_obj = bottom + oop(bottom)->size(); \
duke@435 245 while (next_obj < top) { \
duke@435 246 /* Bottom lies entirely below top, so we can call the */ \
duke@435 247 /* non-memRegion version of oop_iterate below. */ \
duke@435 248 oop(bottom)->oop_iterate(cl); \
duke@435 249 bottom = next_obj; \
duke@435 250 next_obj = bottom + oop(bottom)->size(); \
duke@435 251 } \
duke@435 252 /* Last object. */ \
duke@435 253 oop(bottom)->oop_iterate(cl, mr); \
duke@435 254 } \
duke@435 255 }
duke@435 256
duke@435 257 // (There are only two of these, rather than N, because the split is due
duke@435 258 // only to the introduction of the FilteringClosure, a local part of the
duke@435 259 // impl of this abstraction.)
coleenp@4037 260 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure)
duke@435 261 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure)
duke@435 262
duke@435 263 DirtyCardToOopClosure*
coleenp@4037 264 ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl,
duke@435 265 CardTableModRefBS::PrecisionStyle precision,
duke@435 266 HeapWord* boundary) {
duke@435 267 return new ContiguousSpaceDCTOC(this, cl, precision, boundary);
duke@435 268 }
duke@435 269
jmasa@698 270 void Space::initialize(MemRegion mr,
jmasa@698 271 bool clear_space,
jmasa@698 272 bool mangle_space) {
duke@435 273 HeapWord* bottom = mr.start();
duke@435 274 HeapWord* end = mr.end();
duke@435 275 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
duke@435 276 "invalid space boundaries");
duke@435 277 set_bottom(bottom);
duke@435 278 set_end(end);
jmasa@698 279 if (clear_space) clear(mangle_space);
duke@435 280 }
duke@435 281
jmasa@698 282 void Space::clear(bool mangle_space) {
jmasa@698 283 if (ZapUnusedHeapArea && mangle_space) {
jmasa@698 284 mangle_unused_area();
jmasa@698 285 }
duke@435 286 }
duke@435 287
tonyp@791 288 ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL),
tonyp@791 289 _concurrent_iteration_safe_limit(NULL) {
jmasa@698 290 _mangler = new GenSpaceMangler(this);
jmasa@698 291 }
jmasa@698 292
jmasa@698 293 ContiguousSpace::~ContiguousSpace() {
jmasa@698 294 delete _mangler;
jmasa@698 295 }
jmasa@698 296
jmasa@698 297 void ContiguousSpace::initialize(MemRegion mr,
jmasa@698 298 bool clear_space,
jmasa@698 299 bool mangle_space)
duke@435 300 {
jmasa@698 301 CompactibleSpace::initialize(mr, clear_space, mangle_space);
ysr@782 302 set_concurrent_iteration_safe_limit(top());
duke@435 303 }
duke@435 304
jmasa@698 305 void ContiguousSpace::clear(bool mangle_space) {
duke@435 306 set_top(bottom());
duke@435 307 set_saved_mark();
tonyp@791 308 CompactibleSpace::clear(mangle_space);
duke@435 309 }
duke@435 310
duke@435 311 bool ContiguousSpace::is_in(const void* p) const {
duke@435 312 return _bottom <= p && p < _top;
duke@435 313 }
duke@435 314
duke@435 315 bool ContiguousSpace::is_free_block(const HeapWord* p) const {
duke@435 316 return p >= _top;
duke@435 317 }
duke@435 318
jmasa@698 319 void OffsetTableContigSpace::clear(bool mangle_space) {
jmasa@698 320 ContiguousSpace::clear(mangle_space);
duke@435 321 _offsets.initialize_threshold();
duke@435 322 }
duke@435 323
duke@435 324 void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
duke@435 325 Space::set_bottom(new_bottom);
duke@435 326 _offsets.set_bottom(new_bottom);
duke@435 327 }
duke@435 328
duke@435 329 void OffsetTableContigSpace::set_end(HeapWord* new_end) {
duke@435 330 // Space should not advertize an increase in size
duke@435 331 // until after the underlying offest table has been enlarged.
duke@435 332 _offsets.resize(pointer_delta(new_end, bottom()));
duke@435 333 Space::set_end(new_end);
duke@435 334 }
duke@435 335
jmasa@698 336 #ifndef PRODUCT
jmasa@698 337
jmasa@698 338 void ContiguousSpace::set_top_for_allocations(HeapWord* v) {
jmasa@698 339 mangler()->set_top_for_allocations(v);
jmasa@698 340 }
jmasa@698 341 void ContiguousSpace::set_top_for_allocations() {
jmasa@698 342 mangler()->set_top_for_allocations(top());
jmasa@698 343 }
jmasa@698 344 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) {
jmasa@698 345 mangler()->check_mangled_unused_area(limit);
duke@435 346 }
duke@435 347
jmasa@698 348 void ContiguousSpace::check_mangled_unused_area_complete() {
jmasa@698 349 mangler()->check_mangled_unused_area_complete();
duke@435 350 }
duke@435 351
jmasa@698 352 // Mangled only the unused space that has not previously
jmasa@698 353 // been mangled and that has not been allocated since being
jmasa@698 354 // mangled.
jmasa@698 355 void ContiguousSpace::mangle_unused_area() {
jmasa@698 356 mangler()->mangle_unused_area();
jmasa@698 357 }
jmasa@698 358 void ContiguousSpace::mangle_unused_area_complete() {
jmasa@698 359 mangler()->mangle_unused_area_complete();
jmasa@698 360 }
jmasa@698 361 void ContiguousSpace::mangle_region(MemRegion mr) {
jmasa@698 362 // Although this method uses SpaceMangler::mangle_region() which
jmasa@698 363 // is not specific to a space, the when the ContiguousSpace version
jmasa@698 364 // is called, it is always with regard to a space and this
jmasa@698 365 // bounds checking is appropriate.
jmasa@698 366 MemRegion space_mr(bottom(), end());
jmasa@698 367 assert(space_mr.contains(mr), "Mangling outside space");
jmasa@698 368 SpaceMangler::mangle_region(mr);
jmasa@698 369 }
jmasa@698 370 #endif // NOT_PRODUCT
jmasa@698 371
jmasa@698 372 void CompactibleSpace::initialize(MemRegion mr,
jmasa@698 373 bool clear_space,
jmasa@698 374 bool mangle_space) {
jmasa@698 375 Space::initialize(mr, clear_space, mangle_space);
tonyp@791 376 set_compaction_top(bottom());
tonyp@791 377 _next_compaction_space = NULL;
tonyp@791 378 }
tonyp@791 379
tonyp@791 380 void CompactibleSpace::clear(bool mangle_space) {
tonyp@791 381 Space::clear(mangle_space);
duke@435 382 _compaction_top = bottom();
duke@435 383 }
duke@435 384
duke@435 385 HeapWord* CompactibleSpace::forward(oop q, size_t size,
duke@435 386 CompactPoint* cp, HeapWord* compact_top) {
duke@435 387 // q is alive
duke@435 388 // First check if we should switch compaction space
duke@435 389 assert(this == cp->space, "'this' should be current compaction space.");
duke@435 390 size_t compaction_max_size = pointer_delta(end(), compact_top);
duke@435 391 while (size > compaction_max_size) {
duke@435 392 // switch to next compaction space
duke@435 393 cp->space->set_compaction_top(compact_top);
duke@435 394 cp->space = cp->space->next_compaction_space();
duke@435 395 if (cp->space == NULL) {
duke@435 396 cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen);
duke@435 397 assert(cp->gen != NULL, "compaction must succeed");
duke@435 398 cp->space = cp->gen->first_compaction_space();
duke@435 399 assert(cp->space != NULL, "generation must have a first compaction space");
duke@435 400 }
duke@435 401 compact_top = cp->space->bottom();
duke@435 402 cp->space->set_compaction_top(compact_top);
duke@435 403 cp->threshold = cp->space->initialize_threshold();
duke@435 404 compaction_max_size = pointer_delta(cp->space->end(), compact_top);
duke@435 405 }
duke@435 406
duke@435 407 // store the forwarding pointer into the mark word
duke@435 408 if ((HeapWord*)q != compact_top) {
duke@435 409 q->forward_to(oop(compact_top));
duke@435 410 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
duke@435 411 } else {
duke@435 412 // if the object isn't moving we can just set the mark to the default
duke@435 413 // mark and handle it specially later on.
duke@435 414 q->init_mark();
duke@435 415 assert(q->forwardee() == NULL, "should be forwarded to NULL");
duke@435 416 }
duke@435 417
duke@435 418 compact_top += size;
duke@435 419
duke@435 420 // we need to update the offset table so that the beginnings of objects can be
duke@435 421 // found during scavenge. Note that we are updating the offset table based on
duke@435 422 // where the object will be once the compaction phase finishes.
duke@435 423 if (compact_top > cp->threshold)
duke@435 424 cp->threshold =
duke@435 425 cp->space->cross_threshold(compact_top - size, compact_top);
duke@435 426 return compact_top;
duke@435 427 }
duke@435 428
duke@435 429
duke@435 430 bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words,
duke@435 431 HeapWord* q, size_t deadlength) {
duke@435 432 if (allowed_deadspace_words >= deadlength) {
duke@435 433 allowed_deadspace_words -= deadlength;
jcoomes@916 434 CollectedHeap::fill_with_object(q, deadlength);
jcoomes@916 435 oop(q)->set_mark(oop(q)->mark()->set_marked());
jcoomes@916 436 assert((int) deadlength == oop(q)->size(), "bad filler object size");
duke@435 437 // Recall that we required "q == compaction_top".
duke@435 438 return true;
duke@435 439 } else {
duke@435 440 allowed_deadspace_words = 0;
duke@435 441 return false;
duke@435 442 }
duke@435 443 }
duke@435 444
duke@435 445 #define block_is_always_obj(q) true
duke@435 446 #define obj_size(q) oop(q)->size()
duke@435 447 #define adjust_obj_size(s) s
duke@435 448
duke@435 449 void CompactibleSpace::prepare_for_compaction(CompactPoint* cp) {
duke@435 450 SCAN_AND_FORWARD(cp, end, block_is_obj, block_size);
duke@435 451 }
duke@435 452
duke@435 453 // Faster object search.
duke@435 454 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) {
duke@435 455 SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size);
duke@435 456 }
duke@435 457
duke@435 458 void Space::adjust_pointers() {
duke@435 459 // adjust all the interior pointers to point at the new locations of objects
duke@435 460 // Used by MarkSweep::mark_sweep_phase3()
duke@435 461
duke@435 462 // First check to see if there is any work to be done.
duke@435 463 if (used() == 0) {
duke@435 464 return; // Nothing to do.
duke@435 465 }
duke@435 466
duke@435 467 // Otherwise...
duke@435 468 HeapWord* q = bottom();
duke@435 469 HeapWord* t = end();
duke@435 470
duke@435 471 debug_only(HeapWord* prev_q = NULL);
duke@435 472 while (q < t) {
duke@435 473 if (oop(q)->is_gc_marked()) {
duke@435 474 // q is alive
duke@435 475
duke@435 476 // point all the oops to the new location
duke@435 477 size_t size = oop(q)->adjust_pointers();
duke@435 478
duke@435 479 debug_only(prev_q = q);
duke@435 480
duke@435 481 q += size;
duke@435 482 } else {
duke@435 483 // q is not a live object. But we're not in a compactible space,
duke@435 484 // So we don't have live ranges.
duke@435 485 debug_only(prev_q = q);
duke@435 486 q += block_size(q);
duke@435 487 assert(q > prev_q, "we should be moving forward through memory");
duke@435 488 }
duke@435 489 }
duke@435 490 assert(q == t, "just checking");
duke@435 491 }
duke@435 492
duke@435 493 void CompactibleSpace::adjust_pointers() {
duke@435 494 // Check first is there is any work to do.
duke@435 495 if (used() == 0) {
duke@435 496 return; // Nothing to do.
duke@435 497 }
duke@435 498
duke@435 499 SCAN_AND_ADJUST_POINTERS(adjust_obj_size);
duke@435 500 }
duke@435 501
duke@435 502 void CompactibleSpace::compact() {
duke@435 503 SCAN_AND_COMPACT(obj_size);
duke@435 504 }
duke@435 505
duke@435 506 void Space::print_short() const { print_short_on(tty); }
duke@435 507
duke@435 508 void Space::print_short_on(outputStream* st) const {
duke@435 509 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K,
duke@435 510 (int) ((double) used() * 100 / capacity()));
duke@435 511 }
duke@435 512
duke@435 513 void Space::print() const { print_on(tty); }
duke@435 514
duke@435 515 void Space::print_on(outputStream* st) const {
duke@435 516 print_short_on(st);
duke@435 517 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")",
duke@435 518 bottom(), end());
duke@435 519 }
duke@435 520
duke@435 521 void ContiguousSpace::print_on(outputStream* st) const {
duke@435 522 print_short_on(st);
duke@435 523 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
duke@435 524 bottom(), top(), end());
duke@435 525 }
duke@435 526
duke@435 527 void OffsetTableContigSpace::print_on(outputStream* st) const {
duke@435 528 print_short_on(st);
duke@435 529 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
duke@435 530 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
duke@435 531 bottom(), top(), _offsets.threshold(), end());
duke@435 532 }
duke@435 533
brutisso@3711 534 void ContiguousSpace::verify() const {
duke@435 535 HeapWord* p = bottom();
duke@435 536 HeapWord* t = top();
duke@435 537 HeapWord* prev_p = NULL;
duke@435 538 while (p < t) {
duke@435 539 oop(p)->verify();
duke@435 540 prev_p = p;
duke@435 541 p += oop(p)->size();
duke@435 542 }
duke@435 543 guarantee(p == top(), "end of last object must match end of space");
duke@435 544 if (top() != end()) {
ysr@777 545 guarantee(top() == block_start_const(end()-1) &&
ysr@777 546 top() == block_start_const(top()),
duke@435 547 "top should be start of unallocated block, if it exists");
duke@435 548 }
duke@435 549 }
duke@435 550
coleenp@4037 551 void Space::oop_iterate(ExtendedOopClosure* blk) {
duke@435 552 ObjectToOopClosure blk2(blk);
duke@435 553 object_iterate(&blk2);
duke@435 554 }
duke@435 555
duke@435 556 HeapWord* Space::object_iterate_careful(ObjectClosureCareful* cl) {
duke@435 557 guarantee(false, "NYI");
duke@435 558 return bottom();
duke@435 559 }
duke@435 560
duke@435 561 HeapWord* Space::object_iterate_careful_m(MemRegion mr,
duke@435 562 ObjectClosureCareful* cl) {
duke@435 563 guarantee(false, "NYI");
duke@435 564 return bottom();
duke@435 565 }
duke@435 566
duke@435 567
duke@435 568 void Space::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
duke@435 569 assert(!mr.is_empty(), "Should be non-empty");
duke@435 570 // We use MemRegion(bottom(), end()) rather than used_region() below
duke@435 571 // because the two are not necessarily equal for some kinds of
duke@435 572 // spaces, in particular, certain kinds of free list spaces.
duke@435 573 // We could use the more complicated but more precise:
duke@435 574 // MemRegion(used_region().start(), round_to(used_region().end(), CardSize))
duke@435 575 // but the slight imprecision seems acceptable in the assertion check.
duke@435 576 assert(MemRegion(bottom(), end()).contains(mr),
duke@435 577 "Should be within used space");
duke@435 578 HeapWord* prev = cl->previous(); // max address from last time
duke@435 579 if (prev >= mr.end()) { // nothing to do
duke@435 580 return;
duke@435 581 }
duke@435 582 // This assert will not work when we go from cms space to perm
duke@435 583 // space, and use same closure. Easy fix deferred for later. XXX YSR
duke@435 584 // assert(prev == NULL || contains(prev), "Should be within space");
duke@435 585
duke@435 586 bool last_was_obj_array = false;
duke@435 587 HeapWord *blk_start_addr, *region_start_addr;
duke@435 588 if (prev > mr.start()) {
duke@435 589 region_start_addr = prev;
duke@435 590 blk_start_addr = prev;
jmasa@953 591 // The previous invocation may have pushed "prev" beyond the
jmasa@953 592 // last allocated block yet there may be still be blocks
jmasa@953 593 // in this region due to a particular coalescing policy.
jmasa@953 594 // Relax the assertion so that the case where the unallocated
jmasa@953 595 // block is maintained and "prev" is beyond the unallocated
jmasa@953 596 // block does not cause the assertion to fire.
jmasa@953 597 assert((BlockOffsetArrayUseUnallocatedBlock &&
jmasa@953 598 (!is_in(prev))) ||
jmasa@953 599 (blk_start_addr == block_start(region_start_addr)), "invariant");
duke@435 600 } else {
duke@435 601 region_start_addr = mr.start();
duke@435 602 blk_start_addr = block_start(region_start_addr);
duke@435 603 }
duke@435 604 HeapWord* region_end_addr = mr.end();
duke@435 605 MemRegion derived_mr(region_start_addr, region_end_addr);
duke@435 606 while (blk_start_addr < region_end_addr) {
duke@435 607 const size_t size = block_size(blk_start_addr);
duke@435 608 if (block_is_obj(blk_start_addr)) {
duke@435 609 last_was_obj_array = cl->do_object_bm(oop(blk_start_addr), derived_mr);
duke@435 610 } else {
duke@435 611 last_was_obj_array = false;
duke@435 612 }
duke@435 613 blk_start_addr += size;
duke@435 614 }
duke@435 615 if (!last_was_obj_array) {
duke@435 616 assert((bottom() <= blk_start_addr) && (blk_start_addr <= end()),
duke@435 617 "Should be within (closed) used space");
duke@435 618 assert(blk_start_addr > prev, "Invariant");
duke@435 619 cl->set_previous(blk_start_addr); // min address for next time
duke@435 620 }
duke@435 621 }
duke@435 622
duke@435 623 bool Space::obj_is_alive(const HeapWord* p) const {
duke@435 624 assert (block_is_obj(p), "The address should point to an object");
duke@435 625 return true;
duke@435 626 }
duke@435 627
duke@435 628 void ContiguousSpace::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
duke@435 629 assert(!mr.is_empty(), "Should be non-empty");
duke@435 630 assert(used_region().contains(mr), "Should be within used space");
duke@435 631 HeapWord* prev = cl->previous(); // max address from last time
duke@435 632 if (prev >= mr.end()) { // nothing to do
duke@435 633 return;
duke@435 634 }
duke@435 635 // See comment above (in more general method above) in case you
duke@435 636 // happen to use this method.
duke@435 637 assert(prev == NULL || is_in_reserved(prev), "Should be within space");
duke@435 638
duke@435 639 bool last_was_obj_array = false;
duke@435 640 HeapWord *obj_start_addr, *region_start_addr;
duke@435 641 if (prev > mr.start()) {
duke@435 642 region_start_addr = prev;
duke@435 643 obj_start_addr = prev;
duke@435 644 assert(obj_start_addr == block_start(region_start_addr), "invariant");
duke@435 645 } else {
duke@435 646 region_start_addr = mr.start();
duke@435 647 obj_start_addr = block_start(region_start_addr);
duke@435 648 }
duke@435 649 HeapWord* region_end_addr = mr.end();
duke@435 650 MemRegion derived_mr(region_start_addr, region_end_addr);
duke@435 651 while (obj_start_addr < region_end_addr) {
duke@435 652 oop obj = oop(obj_start_addr);
duke@435 653 const size_t size = obj->size();
duke@435 654 last_was_obj_array = cl->do_object_bm(obj, derived_mr);
duke@435 655 obj_start_addr += size;
duke@435 656 }
duke@435 657 if (!last_was_obj_array) {
duke@435 658 assert((bottom() <= obj_start_addr) && (obj_start_addr <= end()),
duke@435 659 "Should be within (closed) used space");
duke@435 660 assert(obj_start_addr > prev, "Invariant");
duke@435 661 cl->set_previous(obj_start_addr); // min address for next time
duke@435 662 }
duke@435 663 }
duke@435 664
jprovino@4542 665 #if INCLUDE_ALL_GCS
duke@435 666 #define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
duke@435 667 \
duke@435 668 void ContiguousSpace::par_oop_iterate(MemRegion mr, OopClosureType* blk) {\
duke@435 669 HeapWord* obj_addr = mr.start(); \
duke@435 670 HeapWord* t = mr.end(); \
duke@435 671 while (obj_addr < t) { \
duke@435 672 assert(oop(obj_addr)->is_oop(), "Should be an oop"); \
duke@435 673 obj_addr += oop(obj_addr)->oop_iterate(blk); \
duke@435 674 } \
duke@435 675 }
duke@435 676
duke@435 677 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DEFN)
duke@435 678
duke@435 679 #undef ContigSpace_PAR_OOP_ITERATE_DEFN
jprovino@4542 680 #endif // INCLUDE_ALL_GCS
duke@435 681
coleenp@4037 682 void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) {
duke@435 683 if (is_empty()) return;
duke@435 684 HeapWord* obj_addr = bottom();
duke@435 685 HeapWord* t = top();
duke@435 686 // Could call objects iterate, but this is easier.
duke@435 687 while (obj_addr < t) {
duke@435 688 obj_addr += oop(obj_addr)->oop_iterate(blk);
duke@435 689 }
duke@435 690 }
duke@435 691
coleenp@4037 692 void ContiguousSpace::oop_iterate(MemRegion mr, ExtendedOopClosure* blk) {
duke@435 693 if (is_empty()) {
duke@435 694 return;
duke@435 695 }
duke@435 696 MemRegion cur = MemRegion(bottom(), top());
duke@435 697 mr = mr.intersection(cur);
duke@435 698 if (mr.is_empty()) {
duke@435 699 return;
duke@435 700 }
duke@435 701 if (mr.equals(cur)) {
duke@435 702 oop_iterate(blk);
duke@435 703 return;
duke@435 704 }
duke@435 705 assert(mr.end() <= top(), "just took an intersection above");
duke@435 706 HeapWord* obj_addr = block_start(mr.start());
duke@435 707 HeapWord* t = mr.end();
duke@435 708
duke@435 709 // Handle first object specially.
duke@435 710 oop obj = oop(obj_addr);
duke@435 711 SpaceMemRegionOopsIterClosure smr_blk(blk, mr);
duke@435 712 obj_addr += obj->oop_iterate(&smr_blk);
duke@435 713 while (obj_addr < t) {
duke@435 714 oop obj = oop(obj_addr);
duke@435 715 assert(obj->is_oop(), "expected an oop");
duke@435 716 obj_addr += obj->size();
duke@435 717 // If "obj_addr" is not greater than top, then the
duke@435 718 // entire object "obj" is within the region.
duke@435 719 if (obj_addr <= t) {
duke@435 720 obj->oop_iterate(blk);
duke@435 721 } else {
duke@435 722 // "obj" extends beyond end of region
duke@435 723 obj->oop_iterate(&smr_blk);
duke@435 724 break;
duke@435 725 }
duke@435 726 };
duke@435 727 }
duke@435 728
duke@435 729 void ContiguousSpace::object_iterate(ObjectClosure* blk) {
duke@435 730 if (is_empty()) return;
duke@435 731 WaterMark bm = bottom_mark();
duke@435 732 object_iterate_from(bm, blk);
duke@435 733 }
duke@435 734
jmasa@952 735 // For a continguous space object_iterate() and safe_object_iterate()
jmasa@952 736 // are the same.
jmasa@952 737 void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
jmasa@952 738 object_iterate(blk);
jmasa@952 739 }
jmasa@952 740
duke@435 741 void ContiguousSpace::object_iterate_from(WaterMark mark, ObjectClosure* blk) {
duke@435 742 assert(mark.space() == this, "Mark does not match space");
duke@435 743 HeapWord* p = mark.point();
duke@435 744 while (p < top()) {
duke@435 745 blk->do_object(oop(p));
duke@435 746 p += oop(p)->size();
duke@435 747 }
duke@435 748 }
duke@435 749
duke@435 750 HeapWord*
duke@435 751 ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) {
duke@435 752 HeapWord * limit = concurrent_iteration_safe_limit();
duke@435 753 assert(limit <= top(), "sanity check");
duke@435 754 for (HeapWord* p = bottom(); p < limit;) {
duke@435 755 size_t size = blk->do_object_careful(oop(p));
duke@435 756 if (size == 0) {
duke@435 757 return p; // failed at p
duke@435 758 } else {
duke@435 759 p += size;
duke@435 760 }
duke@435 761 }
duke@435 762 return NULL; // all done
duke@435 763 }
duke@435 764
duke@435 765 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
duke@435 766 \
duke@435 767 void ContiguousSpace:: \
duke@435 768 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \
duke@435 769 HeapWord* t; \
duke@435 770 HeapWord* p = saved_mark_word(); \
duke@435 771 assert(p != NULL, "expected saved mark"); \
duke@435 772 \
duke@435 773 const intx interval = PrefetchScanIntervalInBytes; \
duke@435 774 do { \
duke@435 775 t = top(); \
duke@435 776 while (p < t) { \
duke@435 777 Prefetch::write(p, interval); \
duke@435 778 debug_only(HeapWord* prev = p); \
duke@435 779 oop m = oop(p); \
duke@435 780 p += m->oop_iterate(blk); \
duke@435 781 } \
duke@435 782 } while (t < top()); \
duke@435 783 \
duke@435 784 set_saved_mark_word(p); \
duke@435 785 }
duke@435 786
duke@435 787 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN)
duke@435 788
duke@435 789 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN
duke@435 790
duke@435 791 // Very general, slow implementation.
ysr@777 792 HeapWord* ContiguousSpace::block_start_const(const void* p) const {
johnc@4300 793 assert(MemRegion(bottom(), end()).contains(p),
johnc@4300 794 err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
johnc@4300 795 p, bottom(), end()));
duke@435 796 if (p >= top()) {
duke@435 797 return top();
duke@435 798 } else {
duke@435 799 HeapWord* last = bottom();
duke@435 800 HeapWord* cur = last;
duke@435 801 while (cur <= p) {
duke@435 802 last = cur;
duke@435 803 cur += oop(cur)->size();
duke@435 804 }
johnc@4300 805 assert(oop(last)->is_oop(),
johnc@4300 806 err_msg(PTR_FORMAT " should be an object start", last));
duke@435 807 return last;
duke@435 808 }
duke@435 809 }
duke@435 810
duke@435 811 size_t ContiguousSpace::block_size(const HeapWord* p) const {
johnc@4300 812 assert(MemRegion(bottom(), end()).contains(p),
johnc@4300 813 err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
johnc@4300 814 p, bottom(), end()));
duke@435 815 HeapWord* current_top = top();
johnc@4300 816 assert(p <= current_top,
johnc@4300 817 err_msg("p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT,
johnc@4300 818 p, current_top));
johnc@4300 819 assert(p == current_top || oop(p)->is_oop(),
johnc@4300 820 err_msg("p (" PTR_FORMAT ") is not a block start - "
johnc@4300 821 "current_top: " PTR_FORMAT ", is_oop: %s",
johnc@4300 822 p, current_top, BOOL_TO_STR(oop(p)->is_oop())));
johnc@4300 823 if (p < current_top) {
duke@435 824 return oop(p)->size();
johnc@4300 825 } else {
duke@435 826 assert(p == current_top, "just checking");
duke@435 827 return pointer_delta(end(), (HeapWord*) p);
duke@435 828 }
duke@435 829 }
duke@435 830
duke@435 831 // This version requires locking.
duke@435 832 inline HeapWord* ContiguousSpace::allocate_impl(size_t size,
duke@435 833 HeapWord* const end_value) {
tonyp@2715 834 // In G1 there are places where a GC worker can allocates into a
tonyp@2715 835 // region using this serial allocation code without being prone to a
tonyp@2715 836 // race with other GC workers (we ensure that no other GC worker can
tonyp@2715 837 // access the same region at the same time). So the assert below is
tonyp@2715 838 // too strong in the case of G1.
duke@435 839 assert(Heap_lock->owned_by_self() ||
duke@435 840 (SafepointSynchronize::is_at_safepoint() &&
tonyp@2715 841 (Thread::current()->is_VM_thread() || UseG1GC)),
duke@435 842 "not locked");
duke@435 843 HeapWord* obj = top();
duke@435 844 if (pointer_delta(end_value, obj) >= size) {
duke@435 845 HeapWord* new_top = obj + size;
duke@435 846 set_top(new_top);
duke@435 847 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
duke@435 848 return obj;
duke@435 849 } else {
duke@435 850 return NULL;
duke@435 851 }
duke@435 852 }
duke@435 853
duke@435 854 // This version is lock-free.
duke@435 855 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size,
duke@435 856 HeapWord* const end_value) {
duke@435 857 do {
duke@435 858 HeapWord* obj = top();
duke@435 859 if (pointer_delta(end_value, obj) >= size) {
duke@435 860 HeapWord* new_top = obj + size;
duke@435 861 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
duke@435 862 // result can be one of two:
duke@435 863 // the old top value: the exchange succeeded
duke@435 864 // otherwise: the new value of the top is returned.
duke@435 865 if (result == obj) {
duke@435 866 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
duke@435 867 return obj;
duke@435 868 }
duke@435 869 } else {
duke@435 870 return NULL;
duke@435 871 }
duke@435 872 } while (true);
duke@435 873 }
duke@435 874
duke@435 875 // Requires locking.
duke@435 876 HeapWord* ContiguousSpace::allocate(size_t size) {
duke@435 877 return allocate_impl(size, end());
duke@435 878 }
duke@435 879
duke@435 880 // Lock-free.
duke@435 881 HeapWord* ContiguousSpace::par_allocate(size_t size) {
duke@435 882 return par_allocate_impl(size, end());
duke@435 883 }
duke@435 884
duke@435 885 void ContiguousSpace::allocate_temporary_filler(int factor) {
duke@435 886 // allocate temporary type array decreasing free size with factor 'factor'
duke@435 887 assert(factor >= 0, "just checking");
duke@435 888 size_t size = pointer_delta(end(), top());
duke@435 889
duke@435 890 // if space is full, return
duke@435 891 if (size == 0) return;
duke@435 892
duke@435 893 if (factor > 0) {
duke@435 894 size -= size/factor;
duke@435 895 }
duke@435 896 size = align_object_size(size);
duke@435 897
kvn@1926 898 const size_t array_header_size = typeArrayOopDesc::header_size(T_INT);
kvn@1926 899 if (size >= (size_t)align_object_size(array_header_size)) {
kvn@1926 900 size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint));
duke@435 901 // allocate uninitialized int array
duke@435 902 typeArrayOop t = (typeArrayOop) allocate(size);
duke@435 903 assert(t != NULL, "allocation should succeed");
duke@435 904 t->set_mark(markOopDesc::prototype());
duke@435 905 t->set_klass(Universe::intArrayKlassObj());
duke@435 906 t->set_length((int)length);
duke@435 907 } else {
kvn@1926 908 assert(size == CollectedHeap::min_fill_size(),
duke@435 909 "size for smallest fake object doesn't match");
duke@435 910 instanceOop obj = (instanceOop) allocate(size);
duke@435 911 obj->set_mark(markOopDesc::prototype());
coleenp@602 912 obj->set_klass_gap(0);
never@1577 913 obj->set_klass(SystemDictionary::Object_klass());
duke@435 914 }
duke@435 915 }
duke@435 916
jmasa@698 917 void EdenSpace::clear(bool mangle_space) {
jmasa@698 918 ContiguousSpace::clear(mangle_space);
duke@435 919 set_soft_end(end());
duke@435 920 }
duke@435 921
duke@435 922 // Requires locking.
duke@435 923 HeapWord* EdenSpace::allocate(size_t size) {
duke@435 924 return allocate_impl(size, soft_end());
duke@435 925 }
duke@435 926
duke@435 927 // Lock-free.
duke@435 928 HeapWord* EdenSpace::par_allocate(size_t size) {
duke@435 929 return par_allocate_impl(size, soft_end());
duke@435 930 }
duke@435 931
duke@435 932 HeapWord* ConcEdenSpace::par_allocate(size_t size)
duke@435 933 {
duke@435 934 do {
duke@435 935 // The invariant is top() should be read before end() because
duke@435 936 // top() can't be greater than end(), so if an update of _soft_end
duke@435 937 // occurs between 'end_val = end();' and 'top_val = top();' top()
duke@435 938 // also can grow up to the new end() and the condition
duke@435 939 // 'top_val > end_val' is true. To ensure the loading order
duke@435 940 // OrderAccess::loadload() is required after top() read.
duke@435 941 HeapWord* obj = top();
duke@435 942 OrderAccess::loadload();
duke@435 943 if (pointer_delta(*soft_end_addr(), obj) >= size) {
duke@435 944 HeapWord* new_top = obj + size;
duke@435 945 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
duke@435 946 // result can be one of two:
duke@435 947 // the old top value: the exchange succeeded
duke@435 948 // otherwise: the new value of the top is returned.
duke@435 949 if (result == obj) {
duke@435 950 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
duke@435 951 return obj;
duke@435 952 }
duke@435 953 } else {
duke@435 954 return NULL;
duke@435 955 }
duke@435 956 } while (true);
duke@435 957 }
duke@435 958
duke@435 959
duke@435 960 HeapWord* OffsetTableContigSpace::initialize_threshold() {
duke@435 961 return _offsets.initialize_threshold();
duke@435 962 }
duke@435 963
duke@435 964 HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) {
duke@435 965 _offsets.alloc_block(start, end);
duke@435 966 return _offsets.threshold();
duke@435 967 }
duke@435 968
duke@435 969 OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray,
duke@435 970 MemRegion mr) :
duke@435 971 _offsets(sharedOffsetArray, mr),
duke@435 972 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true)
duke@435 973 {
duke@435 974 _offsets.set_contig_space(this);
jmasa@698 975 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle);
duke@435 976 }
duke@435 977
duke@435 978 #define OBJ_SAMPLE_INTERVAL 0
duke@435 979 #define BLOCK_SAMPLE_INTERVAL 100
duke@435 980
brutisso@3711 981 void OffsetTableContigSpace::verify() const {
duke@435 982 HeapWord* p = bottom();
duke@435 983 HeapWord* prev_p = NULL;
duke@435 984 int objs = 0;
duke@435 985 int blocks = 0;
duke@435 986
duke@435 987 if (VerifyObjectStartArray) {
duke@435 988 _offsets.verify();
duke@435 989 }
duke@435 990
duke@435 991 while (p < top()) {
duke@435 992 size_t size = oop(p)->size();
duke@435 993 // For a sampling of objects in the space, find it using the
duke@435 994 // block offset table.
duke@435 995 if (blocks == BLOCK_SAMPLE_INTERVAL) {
ysr@777 996 guarantee(p == block_start_const(p + (size/2)),
ysr@777 997 "check offset computation");
duke@435 998 blocks = 0;
duke@435 999 } else {
duke@435 1000 blocks++;
duke@435 1001 }
duke@435 1002
duke@435 1003 if (objs == OBJ_SAMPLE_INTERVAL) {
duke@435 1004 oop(p)->verify();
duke@435 1005 objs = 0;
duke@435 1006 } else {
duke@435 1007 objs++;
duke@435 1008 }
duke@435 1009 prev_p = p;
duke@435 1010 p += size;
duke@435 1011 }
duke@435 1012 guarantee(p == top(), "end of last object must match end of space");
duke@435 1013 }
duke@435 1014
duke@435 1015
jcoomes@873 1016 size_t TenuredSpace::allowed_dead_ratio() const {
duke@435 1017 return MarkSweepDeadRatio;
duke@435 1018 }

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