rev 47223 : [mq]: heapz8
rev 47224 : [mq]: heap9a

   1 /*
   2  * Copyright (c) 2001, 2017, 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 "gc/shared/allocTracer.hpp"
  28 #include "gc/shared/barrierSet.inline.hpp"
  29 #include "gc/shared/collectedHeap.hpp"
  30 #include "gc/shared/collectedHeap.inline.hpp"
  31 #include "gc/shared/gcHeapSummary.hpp"
  32 #include "gc/shared/gcTrace.hpp"
  33 #include "gc/shared/gcTraceTime.inline.hpp"
  34 #include "gc/shared/gcWhen.hpp"
  35 #include "gc/shared/vmGCOperations.hpp"
  36 #include "logging/log.hpp"
  37 #include "memory/metaspace.hpp"
  38 #include "memory/resourceArea.hpp"
  39 #include "oops/instanceMirrorKlass.hpp"
  40 #include "oops/oop.inline.hpp"
  41 #include "runtime/heapMonitoring.hpp"
  42 #include "runtime/init.hpp"
  43 #include "runtime/thread.inline.hpp"
  44 #include "services/heapDumper.hpp"
  45 #include "utilities/align.hpp"
  46 
  47 
  48 #ifdef ASSERT
  49 int CollectedHeap::_fire_out_of_memory_count = 0;
  50 #endif
  51 
  52 size_t CollectedHeap::_filler_array_max_size = 0;
  53 
  54 template <>
  55 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
  56   st->print_cr("GC heap %s", m.is_before ? "before" : "after");
  57   st->print_raw(m);
  58 }
  59 
  60 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
  61   if (!should_log()) {
  62     return;
  63   }
  64 
  65   double timestamp = fetch_timestamp();
  66   MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
  67   int index = compute_log_index();
  68   _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
  69   _records[index].timestamp = timestamp;
  70   _records[index].data.is_before = before;
  71   stringStream st(_records[index].data.buffer(), _records[index].data.size());
  72 
  73   st.print_cr("{Heap %s GC invocations=%u (full %u):",
  74                  before ? "before" : "after",
  75                  heap->total_collections(),
  76                  heap->total_full_collections());
  77 
  78   heap->print_on(&st);
  79   st.print_cr("}");
  80 }
  81 
  82 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
  83   size_t capacity_in_words = capacity() / HeapWordSize;
  84 
  85   return VirtualSpaceSummary(
  86     reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
  87 }
  88 
  89 GCHeapSummary CollectedHeap::create_heap_summary() {
  90   VirtualSpaceSummary heap_space = create_heap_space_summary();
  91   return GCHeapSummary(heap_space, used());
  92 }
  93 
  94 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
  95   const MetaspaceSizes meta_space(
  96       MetaspaceAux::committed_bytes(),
  97       MetaspaceAux::used_bytes(),
  98       MetaspaceAux::reserved_bytes());
  99   const MetaspaceSizes data_space(
 100       MetaspaceAux::committed_bytes(Metaspace::NonClassType),
 101       MetaspaceAux::used_bytes(Metaspace::NonClassType),
 102       MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
 103   const MetaspaceSizes class_space(
 104       MetaspaceAux::committed_bytes(Metaspace::ClassType),
 105       MetaspaceAux::used_bytes(Metaspace::ClassType),
 106       MetaspaceAux::reserved_bytes(Metaspace::ClassType));
 107 
 108   const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
 109     MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
 110   const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
 111     MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
 112 
 113   return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
 114                           ms_chunk_free_list_summary, class_chunk_free_list_summary);
 115 }
 116 
 117 void CollectedHeap::print_heap_before_gc() {
 118   Universe::print_heap_before_gc();
 119   if (_gc_heap_log != NULL) {
 120     _gc_heap_log->log_heap_before(this);
 121   }
 122 }
 123 
 124 void CollectedHeap::print_heap_after_gc() {
 125   Universe::print_heap_after_gc();
 126   if (_gc_heap_log != NULL) {
 127     _gc_heap_log->log_heap_after(this);
 128   }
 129 }
 130 
 131 void CollectedHeap::print_on_error(outputStream* st) const {
 132   st->print_cr("Heap:");
 133   print_extended_on(st);
 134   st->cr();
 135 
 136   _barrier_set->print_on(st);
 137 }
 138 
 139 void CollectedHeap::register_nmethod(nmethod* nm) {
 140   assert_locked_or_safepoint(CodeCache_lock);
 141 }
 142 
 143 void CollectedHeap::unregister_nmethod(nmethod* nm) {
 144   assert_locked_or_safepoint(CodeCache_lock);
 145 }
 146 
 147 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
 148   const GCHeapSummary& heap_summary = create_heap_summary();
 149   gc_tracer->report_gc_heap_summary(when, heap_summary);
 150 
 151   const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
 152   gc_tracer->report_metaspace_summary(when, metaspace_summary);
 153 }
 154 
 155 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
 156   trace_heap(GCWhen::BeforeGC, gc_tracer);
 157 }
 158 
 159 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
 160   trace_heap(GCWhen::AfterGC, gc_tracer);
 161 }
 162 
 163 // WhiteBox API support for concurrent collectors.  These are the
 164 // default implementations, for collectors which don't support this
 165 // feature.
 166 bool CollectedHeap::supports_concurrent_phase_control() const {
 167   return false;
 168 }
 169 
 170 const char* const* CollectedHeap::concurrent_phases() const {
 171   static const char* const result[] = { NULL };
 172   return result;
 173 }
 174 
 175 bool CollectedHeap::request_concurrent_phase(const char* phase) {
 176   return false;
 177 }
 178 
 179 // Memory state functions.
 180 
 181 
 182 CollectedHeap::CollectedHeap() :
 183   _barrier_set(NULL),
 184   _is_gc_active(false),
 185   _total_collections(0),
 186   _total_full_collections(0),
 187   _gc_cause(GCCause::_no_gc),
 188   _gc_lastcause(GCCause::_no_gc),
 189   _defer_initial_card_mark(false) // strengthened by subclass in pre_initialize() below.
 190 {
 191   const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
 192   const size_t elements_per_word = HeapWordSize / sizeof(jint);
 193   _filler_array_max_size = align_object_size(filler_array_hdr_size() +
 194                                              max_len / elements_per_word);
 195 
 196   NOT_PRODUCT(_promotion_failure_alot_count = 0;)
 197   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
 198 
 199   if (UsePerfData) {
 200     EXCEPTION_MARK;
 201 
 202     // create the gc cause jvmstat counters
 203     _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
 204                              80, GCCause::to_string(_gc_cause), CHECK);
 205 
 206     _perf_gc_lastcause =
 207                 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
 208                              80, GCCause::to_string(_gc_lastcause), CHECK);
 209   }
 210 
 211   // Create the ring log
 212   if (LogEvents) {
 213     _gc_heap_log = new GCHeapLog();
 214   } else {
 215     _gc_heap_log = NULL;
 216   }
 217 }
 218 
 219 // This interface assumes that it's being called by the
 220 // vm thread. It collects the heap assuming that the
 221 // heap lock is already held and that we are executing in
 222 // the context of the vm thread.
 223 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
 224   assert(Thread::current()->is_VM_thread(), "Precondition#1");
 225   assert(Heap_lock->is_locked(), "Precondition#2");
 226   GCCauseSetter gcs(this, cause);
 227   switch (cause) {
 228     case GCCause::_heap_inspection:
 229     case GCCause::_heap_dump:
 230     case GCCause::_metadata_GC_threshold : {
 231       HandleMark hm;
 232       do_full_collection(false);        // don't clear all soft refs
 233       break;
 234     }
 235     case GCCause::_metadata_GC_clear_soft_refs: {
 236       HandleMark hm;
 237       do_full_collection(true);         // do clear all soft refs
 238       break;
 239     }
 240     default:
 241       ShouldNotReachHere(); // Unexpected use of this function
 242   }
 243 }
 244 
 245 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
 246   _barrier_set = barrier_set;
 247   oopDesc::set_bs(_barrier_set);
 248 }
 249 
 250 void CollectedHeap::pre_initialize() {
 251   // Used for ReduceInitialCardMarks (when COMPILER2 is used);
 252   // otherwise remains unused.
 253 #if defined(COMPILER2) || INCLUDE_JVMCI
 254   _defer_initial_card_mark = is_server_compilation_mode_vm() &&  ReduceInitialCardMarks && can_elide_tlab_store_barriers()
 255                              && (DeferInitialCardMark || card_mark_must_follow_store());
 256 #else
 257   assert(_defer_initial_card_mark == false, "Who would set it?");
 258 #endif
 259 }
 260 
 261 #ifndef PRODUCT
 262 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
 263   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 264     for (size_t slot = 0; slot < size; slot += 1) {
 265       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
 266              "Found badHeapWordValue in post-allocation check");
 267     }
 268   }
 269 }
 270 
 271 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
 272   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 273     for (size_t slot = 0; slot < size; slot += 1) {
 274       assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
 275              "Found non badHeapWordValue in pre-allocation check");
 276     }
 277   }
 278 }
 279 #endif // PRODUCT
 280 
 281 #ifdef ASSERT
 282 void CollectedHeap::check_for_valid_allocation_state() {
 283   Thread *thread = Thread::current();
 284   // How to choose between a pending exception and a potential
 285   // OutOfMemoryError?  Don't allow pending exceptions.
 286   // This is a VM policy failure, so how do we exhaustively test it?
 287   assert(!thread->has_pending_exception(),
 288          "shouldn't be allocating with pending exception");
 289   if (StrictSafepointChecks) {
 290     assert(thread->allow_allocation(),
 291            "Allocation done by thread for which allocation is blocked "
 292            "by No_Allocation_Verifier!");
 293     // Allocation of an oop can always invoke a safepoint,
 294     // hence, the true argument
 295     thread->check_for_valid_safepoint_state(true);
 296   }
 297 }
 298 #endif
 299 
 300 HeapWord* CollectedHeap::handle_heap_sampling(Thread* thread, HeapWord* obj, size_t size) {
 301   // We can come here for three reasons:
 302   //  - We either really did fill the tlab.
 303   //  - We pretended to everyone we did and we want to sample.
 304   //  - Both of the above reasons are true at the same time.
 305   if (HeapMonitoring::enabled()) {
 306     if (thread->tlab().should_sample()) {
 307       HeapWord *end = thread->tlab().end();
 308       thread->tlab().set_back_actual_end();
 309 
 310       // If we don't have an object yet, try to allocate it.
 311       if (obj == NULL) {
 312         // The tlab could still have space after this sample.
 313         obj = thread->tlab().allocate(size);
 314       }
 315 
 316       // Is the object allocated now?
 317       // If not, this means we have to wait till a new TLAB, let the subsequent
 318       // call to handle_heap_sampling pick the next sample.
 319       if (obj != NULL) {
 320         // Object is allocated, sample it now.
 321         HeapMonitoring::object_alloc_do_sample(thread,
 322                                                reinterpret_cast<oopDesc*>(obj),
 323                                                size * HeapWordSize);
 324         // Pick a next sample in this case, we allocated right.
 325         thread->tlab().pick_next_sample(thread->tlab().top() - end);
 326       }
 327     }
 328   }
 329 
 330   return obj;
 331 }
 332 
 333 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
 334   HeapWord* obj = handle_heap_sampling(thread, NULL, size);
 335   bool should_sample = thread->tlab().should_sample();
 336 
 337   if (obj != NULL) {
 338     return obj;
 339   }
 340 
 341   // Retain tlab and allocate object in shared space if
 342   // the amount free in the tlab is too large to discard.
 343   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
 344     thread->tlab().record_slow_allocation(size);
 345     return NULL;
 346   }
 347 
 348   // Discard tlab and allocate a new one.
 349   // To minimize fragmentation, the last TLAB may be smaller than the rest.
 350   size_t new_tlab_size = thread->tlab().compute_size(size);
 351 
 352   thread->tlab().clear_before_allocation();
 353 
 354   if (new_tlab_size == 0) {
 355     return NULL;
 356   }
 357 
 358   // Allocate a new TLAB...
 359   obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
 360   if (obj == NULL) {
 361     return NULL;
 362   }
 363 
 364   AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
 365 
 366   if (ZeroTLAB) {
 367     // ..and clear it.
 368     Copy::zero_to_words(obj, new_tlab_size);
 369   } else {
 370     // ...and zap just allocated object.
 371 #ifdef ASSERT
 372     // Skip mangling the space corresponding to the object header to
 373     // ensure that the returned space is not considered parsable by
 374     // any concurrent GC thread.
 375     size_t hdr_size = oopDesc::header_size();
 376     Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
 377 #endif // ASSERT
 378   }
 379   thread->tlab().fill(obj, obj + size, new_tlab_size);
 380 
 381   if (should_sample) {
 382     return handle_heap_sampling(thread, obj, size);
 383   } else {
 384     return obj;
 385   }
 386 }
 387 
 388 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
 389   MemRegion deferred = thread->deferred_card_mark();
 390   if (!deferred.is_empty()) {
 391     assert(_defer_initial_card_mark, "Otherwise should be empty");
 392     {
 393       // Verify that the storage points to a parsable object in heap
 394       DEBUG_ONLY(oop old_obj = oop(deferred.start());)
 395       assert(is_in(old_obj), "Not in allocated heap");
 396       assert(!can_elide_initializing_store_barrier(old_obj),
 397              "Else should have been filtered in new_store_pre_barrier()");
 398       assert(oopDesc::is_oop(old_obj, true), "Not an oop");
 399       assert(deferred.word_size() == (size_t)(old_obj->size()),
 400              "Mismatch: multiple objects?");
 401     }
 402     BarrierSet* bs = barrier_set();
 403     assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
 404     bs->write_region(deferred);
 405     // "Clear" the deferred_card_mark field
 406     thread->set_deferred_card_mark(MemRegion());
 407   }
 408   assert(thread->deferred_card_mark().is_empty(), "invariant");
 409 }
 410 
 411 size_t CollectedHeap::max_tlab_size() const {
 412   // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
 413   // This restriction could be removed by enabling filling with multiple arrays.
 414   // If we compute that the reasonable way as
 415   //    header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
 416   // we'll overflow on the multiply, so we do the divide first.
 417   // We actually lose a little by dividing first,
 418   // but that just makes the TLAB  somewhat smaller than the biggest array,
 419   // which is fine, since we'll be able to fill that.
 420   size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
 421               sizeof(jint) *
 422               ((juint) max_jint / (size_t) HeapWordSize);
 423   return align_down(max_int_size, MinObjAlignment);
 424 }
 425 
 426 // Helper for ReduceInitialCardMarks. For performance,
 427 // compiled code may elide card-marks for initializing stores
 428 // to a newly allocated object along the fast-path. We
 429 // compensate for such elided card-marks as follows:
 430 // (a) Generational, non-concurrent collectors, such as
 431 //     GenCollectedHeap(ParNew,DefNew,Tenured) and
 432 //     ParallelScavengeHeap(ParallelGC, ParallelOldGC)
 433 //     need the card-mark if and only if the region is
 434 //     in the old gen, and do not care if the card-mark
 435 //     succeeds or precedes the initializing stores themselves,
 436 //     so long as the card-mark is completed before the next
 437 //     scavenge. For all these cases, we can do a card mark
 438 //     at the point at which we do a slow path allocation
 439 //     in the old gen, i.e. in this call.
 440 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
 441 //     in addition that the card-mark for an old gen allocated
 442 //     object strictly follow any associated initializing stores.
 443 //     In these cases, the memRegion remembered below is
 444 //     used to card-mark the entire region either just before the next
 445 //     slow-path allocation by this thread or just before the next scavenge or
 446 //     CMS-associated safepoint, whichever of these events happens first.
 447 //     (The implicit assumption is that the object has been fully
 448 //     initialized by this point, a fact that we assert when doing the
 449 //     card-mark.)
 450 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
 451 //     G1 concurrent marking is in progress an SATB (pre-write-)barrier
 452 //     is used to remember the pre-value of any store. Initializing
 453 //     stores will not need this barrier, so we need not worry about
 454 //     compensating for the missing pre-barrier here. Turning now
 455 //     to the post-barrier, we note that G1 needs a RS update barrier
 456 //     which simply enqueues a (sequence of) dirty cards which may
 457 //     optionally be refined by the concurrent update threads. Note
 458 //     that this barrier need only be applied to a non-young write,
 459 //     but, like in CMS, because of the presence of concurrent refinement
 460 //     (much like CMS' precleaning), must strictly follow the oop-store.
 461 //     Thus, using the same protocol for maintaining the intended
 462 //     invariants turns out, serendepitously, to be the same for both
 463 //     G1 and CMS.
 464 //
 465 // For any future collector, this code should be reexamined with
 466 // that specific collector in mind, and the documentation above suitably
 467 // extended and updated.
 468 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
 469   // If a previous card-mark was deferred, flush it now.
 470   flush_deferred_store_barrier(thread);
 471   if (can_elide_initializing_store_barrier(new_obj) ||
 472       new_obj->is_typeArray()) {
 473     // Arrays of non-references don't need a pre-barrier.
 474     // The deferred_card_mark region should be empty
 475     // following the flush above.
 476     assert(thread->deferred_card_mark().is_empty(), "Error");
 477   } else {
 478     MemRegion mr((HeapWord*)new_obj, new_obj->size());
 479     assert(!mr.is_empty(), "Error");
 480     if (_defer_initial_card_mark) {
 481       // Defer the card mark
 482       thread->set_deferred_card_mark(mr);
 483     } else {
 484       // Do the card mark
 485       BarrierSet* bs = barrier_set();
 486       assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
 487       bs->write_region(mr);
 488     }
 489   }
 490   return new_obj;
 491 }
 492 
 493 size_t CollectedHeap::filler_array_hdr_size() {
 494   return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
 495 }
 496 
 497 size_t CollectedHeap::filler_array_min_size() {
 498   return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
 499 }
 500 
 501 #ifdef ASSERT
 502 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
 503 {
 504   assert(words >= min_fill_size(), "too small to fill");
 505   assert(is_object_aligned(words), "unaligned size");
 506   assert(Universe::heap()->is_in_reserved(start), "not in heap");
 507   assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
 508 }
 509 
 510 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
 511 {
 512   if (ZapFillerObjects && zap) {
 513     Copy::fill_to_words(start + filler_array_hdr_size(),
 514                         words - filler_array_hdr_size(), 0XDEAFBABE);
 515   }
 516 }
 517 #endif // ASSERT
 518 
 519 void
 520 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
 521 {
 522   assert(words >= filler_array_min_size(), "too small for an array");
 523   assert(words <= filler_array_max_size(), "too big for a single object");
 524 
 525   const size_t payload_size = words - filler_array_hdr_size();
 526   const size_t len = payload_size * HeapWordSize / sizeof(jint);
 527   assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
 528 
 529   // Set the length first for concurrent GC.
 530   ((arrayOop)start)->set_length((int)len);
 531   post_allocation_setup_common(Universe::intArrayKlassObj(), start);
 532   DEBUG_ONLY(zap_filler_array(start, words, zap);)
 533 }
 534 
 535 void
 536 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
 537 {
 538   assert(words <= filler_array_max_size(), "too big for a single object");
 539 
 540   if (words >= filler_array_min_size()) {
 541     fill_with_array(start, words, zap);
 542   } else if (words > 0) {
 543     assert(words == min_fill_size(), "unaligned size");
 544     post_allocation_setup_common(SystemDictionary::Object_klass(), start);
 545   }
 546 }
 547 
 548 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
 549 {
 550   DEBUG_ONLY(fill_args_check(start, words);)
 551   HandleMark hm;  // Free handles before leaving.
 552   fill_with_object_impl(start, words, zap);
 553 }
 554 
 555 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
 556 {
 557   DEBUG_ONLY(fill_args_check(start, words);)
 558   HandleMark hm;  // Free handles before leaving.
 559 
 560   // Multiple objects may be required depending on the filler array maximum size. Fill
 561   // the range up to that with objects that are filler_array_max_size sized. The
 562   // remainder is filled with a single object.
 563   const size_t min = min_fill_size();
 564   const size_t max = filler_array_max_size();
 565   while (words > max) {
 566     const size_t cur = (words - max) >= min ? max : max - min;
 567     fill_with_array(start, cur, zap);
 568     start += cur;
 569     words -= cur;
 570   }
 571 
 572   fill_with_object_impl(start, words, zap);
 573 }
 574 
 575 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
 576   guarantee(false, "thread-local allocation buffers not supported");
 577   return NULL;
 578 }
 579 
 580 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
 581   // The second disjunct in the assertion below makes a concession
 582   // for the start-up verification done while the VM is being
 583   // created. Callers be careful that you know that mutators
 584   // aren't going to interfere -- for instance, this is permissible
 585   // if we are still single-threaded and have either not yet
 586   // started allocating (nothing much to verify) or we have
 587   // started allocating but are now a full-fledged JavaThread
 588   // (and have thus made our TLAB's) available for filling.
 589   assert(SafepointSynchronize::is_at_safepoint() ||
 590          !is_init_completed(),
 591          "Should only be called at a safepoint or at start-up"
 592          " otherwise concurrent mutator activity may make heap "
 593          " unparsable again");
 594   const bool use_tlab = UseTLAB;
 595   const bool deferred = _defer_initial_card_mark;
 596   // The main thread starts allocating via a TLAB even before it
 597   // has added itself to the threads list at vm boot-up.
 598   assert(!use_tlab || Threads::first() != NULL,
 599          "Attempt to fill tlabs before main thread has been added"
 600          " to threads list is doomed to failure!");
 601   for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 602      if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
 603 #if defined(COMPILER2) || INCLUDE_JVMCI
 604      // The deferred store barriers must all have been flushed to the
 605      // card-table (or other remembered set structure) before GC starts
 606      // processing the card-table (or other remembered set).
 607      if (deferred) flush_deferred_store_barrier(thread);
 608 #else
 609      assert(!deferred, "Should be false");
 610      assert(thread->deferred_card_mark().is_empty(), "Should be empty");
 611 #endif
 612   }
 613 }
 614 
 615 void CollectedHeap::accumulate_statistics_all_tlabs() {
 616   if (UseTLAB) {
 617     assert(SafepointSynchronize::is_at_safepoint() ||
 618          !is_init_completed(),
 619          "should only accumulate statistics on tlabs at safepoint");
 620 
 621     ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
 622   }
 623 }
 624 
 625 void CollectedHeap::resize_all_tlabs() {
 626   if (UseTLAB) {
 627     assert(SafepointSynchronize::is_at_safepoint() ||
 628          !is_init_completed(),
 629          "should only resize tlabs at safepoint");
 630 
 631     ThreadLocalAllocBuffer::resize_all_tlabs();
 632   }
 633 }
 634 
 635 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
 636   assert(timer != NULL, "timer is null");
 637   if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
 638     GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
 639     HeapDumper::dump_heap();
 640   }
 641 
 642   LogTarget(Trace, gc, classhisto) lt;
 643   if (lt.is_enabled()) {
 644     GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
 645     ResourceMark rm;
 646     LogStream ls(lt);
 647     VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
 648     inspector.doit();
 649   }
 650 }
 651 
 652 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
 653   full_gc_dump(timer, true);
 654 }
 655 
 656 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
 657   full_gc_dump(timer, false);
 658 }
 659 
 660 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
 661   // It is important to do this in a way such that concurrent readers can't
 662   // temporarily think something is in the heap.  (Seen this happen in asserts.)
 663   _reserved.set_word_size(0);
 664   _reserved.set_start(start);
 665   _reserved.set_end(end);
 666 }
--- EOF ---