1 /* 2 * Copyright (c) 2001, 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 "gc/parallel/adjoiningGenerations.hpp" 27 #include "gc/parallel/adjoiningVirtualSpaces.hpp" 28 #include "gc/parallel/cardTableExtension.hpp" 29 #include "gc/parallel/gcTaskManager.hpp" 30 #include "gc/parallel/generationSizer.hpp" 31 #include "gc/parallel/parallelScavengeHeap.inline.hpp" 32 #include "gc/parallel/psAdaptiveSizePolicy.hpp" 33 #include "gc/parallel/psMarkSweep.hpp" 34 #include "gc/parallel/psParallelCompact.hpp" 35 #include "gc/parallel/psPromotionManager.hpp" 36 #include "gc/parallel/psScavenge.hpp" 37 #include "gc/parallel/vmPSOperations.hpp" 38 #include "gc/shared/gcHeapSummary.hpp" 39 #include "gc/shared/gcLocker.inline.hpp" 40 #include "gc/shared/gcWhen.hpp" 41 #include "logging/log.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "runtime/handles.inline.hpp" 44 #include "runtime/java.hpp" 45 #include "runtime/vmThread.hpp" 46 #include "services/memTracker.hpp" 47 #include "utilities/vmError.hpp" 48 49 PSYoungGen* ParallelScavengeHeap::_young_gen = NULL; 50 PSOldGen* ParallelScavengeHeap::_old_gen = NULL; 51 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL; 52 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL; 53 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL; 54 55 jint ParallelScavengeHeap::initialize() { 56 CollectedHeap::pre_initialize(); 57 58 const size_t heap_size = _collector_policy->max_heap_byte_size(); 59 60 ReservedSpace heap_rs = Universe::reserve_heap(heap_size, _collector_policy->heap_alignment()); 61 62 os::trace_page_sizes("ps main", _collector_policy->min_heap_byte_size(), 63 heap_size, generation_alignment(), 64 heap_rs.base(), 65 heap_rs.size()); 66 67 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size())); 68 69 CardTableExtension* const barrier_set = new CardTableExtension(reserved_region()); 70 barrier_set->initialize(); 71 set_barrier_set(barrier_set); 72 73 // Make up the generations 74 // Calculate the maximum size that a generation can grow. This 75 // includes growth into the other generation. Note that the 76 // parameter _max_gen_size is kept as the maximum 77 // size of the generation as the boundaries currently stand. 78 // _max_gen_size is still used as that value. 79 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0; 80 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0; 81 82 _gens = new AdjoiningGenerations(heap_rs, _collector_policy, generation_alignment()); 83 84 _old_gen = _gens->old_gen(); 85 _young_gen = _gens->young_gen(); 86 87 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes(); 88 const size_t old_capacity = _old_gen->capacity_in_bytes(); 89 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity); 90 _size_policy = 91 new PSAdaptiveSizePolicy(eden_capacity, 92 initial_promo_size, 93 young_gen()->to_space()->capacity_in_bytes(), 94 _collector_policy->gen_alignment(), 95 max_gc_pause_sec, 96 max_gc_minor_pause_sec, 97 GCTimeRatio 98 ); 99 100 assert(!UseAdaptiveGCBoundary || 101 (old_gen()->virtual_space()->high_boundary() == 102 young_gen()->virtual_space()->low_boundary()), 103 "Boundaries must meet"); 104 // initialize the policy counters - 2 collectors, 3 generations 105 _gc_policy_counters = 106 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy); 107 108 // Set up the GCTaskManager 109 _gc_task_manager = GCTaskManager::create(ParallelGCThreads); 110 111 if (UseParallelOldGC && !PSParallelCompact::initialize()) { 112 return JNI_ENOMEM; 113 } 114 115 return JNI_OK; 116 } 117 118 void ParallelScavengeHeap::post_initialize() { 119 // Need to init the tenuring threshold 120 PSScavenge::initialize(); 121 if (UseParallelOldGC) { 122 PSParallelCompact::post_initialize(); 123 } else { 124 PSMarkSweep::initialize(); 125 } 126 PSPromotionManager::initialize(); 127 } 128 129 void ParallelScavengeHeap::update_counters() { 130 young_gen()->update_counters(); 131 old_gen()->update_counters(); 132 MetaspaceCounters::update_performance_counters(); 133 CompressedClassSpaceCounters::update_performance_counters(); 134 } 135 136 size_t ParallelScavengeHeap::capacity() const { 137 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes(); 138 return value; 139 } 140 141 size_t ParallelScavengeHeap::used() const { 142 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes(); 143 return value; 144 } 145 146 bool ParallelScavengeHeap::is_maximal_no_gc() const { 147 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc(); 148 } 149 150 151 size_t ParallelScavengeHeap::max_capacity() const { 152 size_t estimated = reserved_region().byte_size(); 153 if (UseAdaptiveSizePolicy) { 154 estimated -= _size_policy->max_survivor_size(young_gen()->max_size()); 155 } else { 156 estimated -= young_gen()->to_space()->capacity_in_bytes(); 157 } 158 return MAX2(estimated, capacity()); 159 } 160 161 bool ParallelScavengeHeap::is_in(const void* p) const { 162 return young_gen()->is_in(p) || old_gen()->is_in(p); 163 } 164 165 bool ParallelScavengeHeap::is_in_reserved(const void* p) const { 166 return young_gen()->is_in_reserved(p) || old_gen()->is_in_reserved(p); 167 } 168 169 bool ParallelScavengeHeap::is_scavengable(const void* addr) { 170 return is_in_young((oop)addr); 171 } 172 173 // There are two levels of allocation policy here. 174 // 175 // When an allocation request fails, the requesting thread must invoke a VM 176 // operation, transfer control to the VM thread, and await the results of a 177 // garbage collection. That is quite expensive, and we should avoid doing it 178 // multiple times if possible. 179 // 180 // To accomplish this, we have a basic allocation policy, and also a 181 // failed allocation policy. 182 // 183 // The basic allocation policy controls how you allocate memory without 184 // attempting garbage collection. It is okay to grab locks and 185 // expand the heap, if that can be done without coming to a safepoint. 186 // It is likely that the basic allocation policy will not be very 187 // aggressive. 188 // 189 // The failed allocation policy is invoked from the VM thread after 190 // the basic allocation policy is unable to satisfy a mem_allocate 191 // request. This policy needs to cover the entire range of collection, 192 // heap expansion, and out-of-memory conditions. It should make every 193 // attempt to allocate the requested memory. 194 195 // Basic allocation policy. Should never be called at a safepoint, or 196 // from the VM thread. 197 // 198 // This method must handle cases where many mem_allocate requests fail 199 // simultaneously. When that happens, only one VM operation will succeed, 200 // and the rest will not be executed. For that reason, this method loops 201 // during failed allocation attempts. If the java heap becomes exhausted, 202 // we rely on the size_policy object to force a bail out. 203 HeapWord* ParallelScavengeHeap::mem_allocate( 204 size_t size, 205 bool* gc_overhead_limit_was_exceeded) { 206 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint"); 207 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread"); 208 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 209 210 // In general gc_overhead_limit_was_exceeded should be false so 211 // set it so here and reset it to true only if the gc time 212 // limit is being exceeded as checked below. 213 *gc_overhead_limit_was_exceeded = false; 214 215 HeapWord* result = young_gen()->allocate(size); 216 217 uint loop_count = 0; 218 uint gc_count = 0; 219 uint gclocker_stalled_count = 0; 220 221 while (result == NULL) { 222 // We don't want to have multiple collections for a single filled generation. 223 // To prevent this, each thread tracks the total_collections() value, and if 224 // the count has changed, does not do a new collection. 225 // 226 // The collection count must be read only while holding the heap lock. VM 227 // operations also hold the heap lock during collections. There is a lock 228 // contention case where thread A blocks waiting on the Heap_lock, while 229 // thread B is holding it doing a collection. When thread A gets the lock, 230 // the collection count has already changed. To prevent duplicate collections, 231 // The policy MUST attempt allocations during the same period it reads the 232 // total_collections() value! 233 { 234 MutexLocker ml(Heap_lock); 235 gc_count = total_collections(); 236 237 result = young_gen()->allocate(size); 238 if (result != NULL) { 239 return result; 240 } 241 242 // If certain conditions hold, try allocating from the old gen. 243 result = mem_allocate_old_gen(size); 244 if (result != NULL) { 245 return result; 246 } 247 248 if (gclocker_stalled_count > GCLockerRetryAllocationCount) { 249 return NULL; 250 } 251 252 // Failed to allocate without a gc. 253 if (GC_locker::is_active_and_needs_gc()) { 254 // If this thread is not in a jni critical section, we stall 255 // the requestor until the critical section has cleared and 256 // GC allowed. When the critical section clears, a GC is 257 // initiated by the last thread exiting the critical section; so 258 // we retry the allocation sequence from the beginning of the loop, 259 // rather than causing more, now probably unnecessary, GC attempts. 260 JavaThread* jthr = JavaThread::current(); 261 if (!jthr->in_critical()) { 262 MutexUnlocker mul(Heap_lock); 263 GC_locker::stall_until_clear(); 264 gclocker_stalled_count += 1; 265 continue; 266 } else { 267 if (CheckJNICalls) { 268 fatal("Possible deadlock due to allocating while" 269 " in jni critical section"); 270 } 271 return NULL; 272 } 273 } 274 } 275 276 if (result == NULL) { 277 // Generate a VM operation 278 VM_ParallelGCFailedAllocation op(size, gc_count); 279 VMThread::execute(&op); 280 281 // Did the VM operation execute? If so, return the result directly. 282 // This prevents us from looping until time out on requests that can 283 // not be satisfied. 284 if (op.prologue_succeeded()) { 285 assert(is_in_or_null(op.result()), "result not in heap"); 286 287 // If GC was locked out during VM operation then retry allocation 288 // and/or stall as necessary. 289 if (op.gc_locked()) { 290 assert(op.result() == NULL, "must be NULL if gc_locked() is true"); 291 continue; // retry and/or stall as necessary 292 } 293 294 // Exit the loop if the gc time limit has been exceeded. 295 // The allocation must have failed above ("result" guarding 296 // this path is NULL) and the most recent collection has exceeded the 297 // gc overhead limit (although enough may have been collected to 298 // satisfy the allocation). Exit the loop so that an out-of-memory 299 // will be thrown (return a NULL ignoring the contents of 300 // op.result()), 301 // but clear gc_overhead_limit_exceeded so that the next collection 302 // starts with a clean slate (i.e., forgets about previous overhead 303 // excesses). Fill op.result() with a filler object so that the 304 // heap remains parsable. 305 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded(); 306 const bool softrefs_clear = collector_policy()->all_soft_refs_clear(); 307 308 if (limit_exceeded && softrefs_clear) { 309 *gc_overhead_limit_was_exceeded = true; 310 size_policy()->set_gc_overhead_limit_exceeded(false); 311 log_trace(gc)("ParallelScavengeHeap::mem_allocate: return NULL because gc_overhead_limit_exceeded is set"); 312 if (op.result() != NULL) { 313 CollectedHeap::fill_with_object(op.result(), size); 314 } 315 return NULL; 316 } 317 318 return op.result(); 319 } 320 } 321 322 // The policy object will prevent us from looping forever. If the 323 // time spent in gc crosses a threshold, we will bail out. 324 loop_count++; 325 if ((result == NULL) && (QueuedAllocationWarningCount > 0) && 326 (loop_count % QueuedAllocationWarningCount == 0)) { 327 warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t" 328 " size=" SIZE_FORMAT, loop_count, size); 329 } 330 } 331 332 return result; 333 } 334 335 // A "death march" is a series of ultra-slow allocations in which a full gc is 336 // done before each allocation, and after the full gc the allocation still 337 // cannot be satisfied from the young gen. This routine detects that condition; 338 // it should be called after a full gc has been done and the allocation 339 // attempted from the young gen. The parameter 'addr' should be the result of 340 // that young gen allocation attempt. 341 void 342 ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) { 343 if (addr != NULL) { 344 _death_march_count = 0; // death march has ended 345 } else if (_death_march_count == 0) { 346 if (should_alloc_in_eden(size)) { 347 _death_march_count = 1; // death march has started 348 } 349 } 350 } 351 352 HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) { 353 if (!should_alloc_in_eden(size) || GC_locker::is_active_and_needs_gc()) { 354 // Size is too big for eden, or gc is locked out. 355 return old_gen()->allocate(size); 356 } 357 358 // If a "death march" is in progress, allocate from the old gen a limited 359 // number of times before doing a GC. 360 if (_death_march_count > 0) { 361 if (_death_march_count < 64) { 362 ++_death_march_count; 363 return old_gen()->allocate(size); 364 } else { 365 _death_march_count = 0; 366 } 367 } 368 return NULL; 369 } 370 371 void ParallelScavengeHeap::do_full_collection(bool clear_all_soft_refs) { 372 if (UseParallelOldGC) { 373 // The do_full_collection() parameter clear_all_soft_refs 374 // is interpreted here as maximum_compaction which will 375 // cause SoftRefs to be cleared. 376 bool maximum_compaction = clear_all_soft_refs; 377 PSParallelCompact::invoke(maximum_compaction); 378 } else { 379 PSMarkSweep::invoke(clear_all_soft_refs); 380 } 381 } 382 383 // Failed allocation policy. Must be called from the VM thread, and 384 // only at a safepoint! Note that this method has policy for allocation 385 // flow, and NOT collection policy. So we do not check for gc collection 386 // time over limit here, that is the responsibility of the heap specific 387 // collection methods. This method decides where to attempt allocations, 388 // and when to attempt collections, but no collection specific policy. 389 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size) { 390 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 391 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); 392 assert(!is_gc_active(), "not reentrant"); 393 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 394 395 // We assume that allocation in eden will fail unless we collect. 396 397 // First level allocation failure, scavenge and allocate in young gen. 398 GCCauseSetter gccs(this, GCCause::_allocation_failure); 399 const bool invoked_full_gc = PSScavenge::invoke(); 400 HeapWord* result = young_gen()->allocate(size); 401 402 // Second level allocation failure. 403 // Mark sweep and allocate in young generation. 404 if (result == NULL && !invoked_full_gc) { 405 do_full_collection(false); 406 result = young_gen()->allocate(size); 407 } 408 409 death_march_check(result, size); 410 411 // Third level allocation failure. 412 // After mark sweep and young generation allocation failure, 413 // allocate in old generation. 414 if (result == NULL) { 415 result = old_gen()->allocate(size); 416 } 417 418 // Fourth level allocation failure. We're running out of memory. 419 // More complete mark sweep and allocate in young generation. 420 if (result == NULL) { 421 do_full_collection(true); 422 result = young_gen()->allocate(size); 423 } 424 425 // Fifth level allocation failure. 426 // After more complete mark sweep, allocate in old generation. 427 if (result == NULL) { 428 result = old_gen()->allocate(size); 429 } 430 431 return result; 432 } 433 434 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) { 435 CollectedHeap::ensure_parsability(retire_tlabs); 436 young_gen()->eden_space()->ensure_parsability(); 437 } 438 439 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const { 440 return young_gen()->eden_space()->tlab_capacity(thr); 441 } 442 443 size_t ParallelScavengeHeap::tlab_used(Thread* thr) const { 444 return young_gen()->eden_space()->tlab_used(thr); 445 } 446 447 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const { 448 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr); 449 } 450 451 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) { 452 return young_gen()->allocate(size); 453 } 454 455 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() { 456 CollectedHeap::accumulate_statistics_all_tlabs(); 457 } 458 459 void ParallelScavengeHeap::resize_all_tlabs() { 460 CollectedHeap::resize_all_tlabs(); 461 } 462 463 bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) { 464 // We don't need barriers for stores to objects in the 465 // young gen and, a fortiori, for initializing stores to 466 // objects therein. 467 return is_in_young(new_obj); 468 } 469 470 // This method is used by System.gc() and JVMTI. 471 void ParallelScavengeHeap::collect(GCCause::Cause cause) { 472 assert(!Heap_lock->owned_by_self(), 473 "this thread should not own the Heap_lock"); 474 475 uint gc_count = 0; 476 uint full_gc_count = 0; 477 { 478 MutexLocker ml(Heap_lock); 479 // This value is guarded by the Heap_lock 480 gc_count = total_collections(); 481 full_gc_count = total_full_collections(); 482 } 483 484 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause); 485 VMThread::execute(&op); 486 } 487 488 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) { 489 young_gen()->object_iterate(cl); 490 old_gen()->object_iterate(cl); 491 } 492 493 494 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const { 495 if (young_gen()->is_in_reserved(addr)) { 496 assert(young_gen()->is_in(addr), 497 "addr should be in allocated part of young gen"); 498 // called from os::print_location by find or VMError 499 if (Debugging || VMError::fatal_error_in_progress()) return NULL; 500 Unimplemented(); 501 } else if (old_gen()->is_in_reserved(addr)) { 502 assert(old_gen()->is_in(addr), 503 "addr should be in allocated part of old gen"); 504 return old_gen()->start_array()->object_start((HeapWord*)addr); 505 } 506 return 0; 507 } 508 509 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const { 510 return oop(addr)->size(); 511 } 512 513 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const { 514 return block_start(addr) == addr; 515 } 516 517 jlong ParallelScavengeHeap::millis_since_last_gc() { 518 return UseParallelOldGC ? 519 PSParallelCompact::millis_since_last_gc() : 520 PSMarkSweep::millis_since_last_gc(); 521 } 522 523 void ParallelScavengeHeap::prepare_for_verify() { 524 ensure_parsability(false); // no need to retire TLABs for verification 525 } 526 527 PSHeapSummary ParallelScavengeHeap::create_ps_heap_summary() { 528 PSOldGen* old = old_gen(); 529 HeapWord* old_committed_end = (HeapWord*)old->virtual_space()->committed_high_addr(); 530 VirtualSpaceSummary old_summary(old->reserved().start(), old_committed_end, old->reserved().end()); 531 SpaceSummary old_space(old->reserved().start(), old_committed_end, old->used_in_bytes()); 532 533 PSYoungGen* young = young_gen(); 534 VirtualSpaceSummary young_summary(young->reserved().start(), 535 (HeapWord*)young->virtual_space()->committed_high_addr(), young->reserved().end()); 536 537 MutableSpace* eden = young_gen()->eden_space(); 538 SpaceSummary eden_space(eden->bottom(), eden->end(), eden->used_in_bytes()); 539 540 MutableSpace* from = young_gen()->from_space(); 541 SpaceSummary from_space(from->bottom(), from->end(), from->used_in_bytes()); 542 543 MutableSpace* to = young_gen()->to_space(); 544 SpaceSummary to_space(to->bottom(), to->end(), to->used_in_bytes()); 545 546 VirtualSpaceSummary heap_summary = create_heap_space_summary(); 547 return PSHeapSummary(heap_summary, used(), old_summary, old_space, young_summary, eden_space, from_space, to_space); 548 } 549 550 void ParallelScavengeHeap::print_on(outputStream* st) const { 551 young_gen()->print_on(st); 552 old_gen()->print_on(st); 553 MetaspaceAux::print_on(st); 554 } 555 556 void ParallelScavengeHeap::print_on_error(outputStream* st) const { 557 this->CollectedHeap::print_on_error(st); 558 559 if (UseParallelOldGC) { 560 st->cr(); 561 PSParallelCompact::print_on_error(st); 562 } 563 } 564 565 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const { 566 PSScavenge::gc_task_manager()->threads_do(tc); 567 } 568 569 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const { 570 PSScavenge::gc_task_manager()->print_threads_on(st); 571 } 572 573 void ParallelScavengeHeap::print_tracing_info() const { 574 if (TraceYoungGenTime) { 575 double time = PSScavenge::accumulated_time()->seconds(); 576 tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time); 577 } 578 if (TraceOldGenTime) { 579 double time = UseParallelOldGC ? PSParallelCompact::accumulated_time()->seconds() : PSMarkSweep::accumulated_time()->seconds(); 580 tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time); 581 } 582 } 583 584 585 void ParallelScavengeHeap::verify(VerifyOption option /* ignored */) { 586 // Why do we need the total_collections()-filter below? 587 if (total_collections() > 0) { 588 log_debug(gc, verify)("Tenured"); 589 old_gen()->verify(); 590 591 log_debug(gc, verify)("Eden"); 592 young_gen()->verify(); 593 } 594 } 595 596 void ParallelScavengeHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) { 597 const PSHeapSummary& heap_summary = create_ps_heap_summary(); 598 gc_tracer->report_gc_heap_summary(when, heap_summary); 599 600 const MetaspaceSummary& metaspace_summary = create_metaspace_summary(); 601 gc_tracer->report_metaspace_summary(when, metaspace_summary); 602 } 603 604 ParallelScavengeHeap* ParallelScavengeHeap::heap() { 605 CollectedHeap* heap = Universe::heap(); 606 assert(heap != NULL, "Uninitialized access to ParallelScavengeHeap::heap()"); 607 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Not a ParallelScavengeHeap"); 608 return (ParallelScavengeHeap*)heap; 609 } 610 611 // Before delegating the resize to the young generation, 612 // the reserved space for the young and old generations 613 // may be changed to accommodate the desired resize. 614 void ParallelScavengeHeap::resize_young_gen(size_t eden_size, 615 size_t survivor_size) { 616 if (UseAdaptiveGCBoundary) { 617 if (size_policy()->bytes_absorbed_from_eden() != 0) { 618 size_policy()->reset_bytes_absorbed_from_eden(); 619 return; // The generation changed size already. 620 } 621 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size); 622 } 623 624 // Delegate the resize to the generation. 625 _young_gen->resize(eden_size, survivor_size); 626 } 627 628 // Before delegating the resize to the old generation, 629 // the reserved space for the young and old generations 630 // may be changed to accommodate the desired resize. 631 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) { 632 if (UseAdaptiveGCBoundary) { 633 if (size_policy()->bytes_absorbed_from_eden() != 0) { 634 size_policy()->reset_bytes_absorbed_from_eden(); 635 return; // The generation changed size already. 636 } 637 gens()->adjust_boundary_for_old_gen_needs(desired_free_space); 638 } 639 640 // Delegate the resize to the generation. 641 _old_gen->resize(desired_free_space); 642 } 643 644 ParallelScavengeHeap::ParStrongRootsScope::ParStrongRootsScope() { 645 // nothing particular 646 } 647 648 ParallelScavengeHeap::ParStrongRootsScope::~ParStrongRootsScope() { 649 // nothing particular 650 } 651 652 #ifndef PRODUCT 653 void ParallelScavengeHeap::record_gen_tops_before_GC() { 654 if (ZapUnusedHeapArea) { 655 young_gen()->record_spaces_top(); 656 old_gen()->record_spaces_top(); 657 } 658 } 659 660 void ParallelScavengeHeap::gen_mangle_unused_area() { 661 if (ZapUnusedHeapArea) { 662 young_gen()->eden_space()->mangle_unused_area(); 663 young_gen()->to_space()->mangle_unused_area(); 664 young_gen()->from_space()->mangle_unused_area(); 665 old_gen()->object_space()->mangle_unused_area(); 666 } 667 } 668 #endif