1 /*
   2  * Copyright (c) 2001, 2020, 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_implementation/shared/gcHeapSummary.hpp"
  28 #include "gc_implementation/shared/gcTrace.hpp"
  29 #include "gc_implementation/shared/gcTraceTime.hpp"
  30 #include "gc_implementation/shared/gcWhen.hpp"
  31 #include "gc_implementation/shared/vmGCOperations.hpp"
  32 #include "gc_interface/allocTracer.hpp"
  33 #include "gc_interface/collectedHeap.hpp"
  34 #include "gc_interface/collectedHeap.inline.hpp"
  35 #include "memory/metaspace.hpp"
  36 #include "oops/oop.inline.hpp"
  37 #include "oops/instanceMirrorKlass.hpp"
  38 #include "runtime/init.hpp"
  39 #include "runtime/thread.inline.hpp"
  40 #include "services/heapDumper.hpp"
  41 
  42 
  43 #ifdef ASSERT
  44 int CollectedHeap::_fire_out_of_memory_count = 0;
  45 #endif
  46 
  47 size_t CollectedHeap::_filler_array_max_size = 0;
  48 
  49 template <>
  50 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
  51   st->print_cr("GC heap %s", m.is_before ? "before" : "after");
  52   st->print_raw(m);
  53 }
  54 
  55 void GCHeapLog::log_heap(bool before) {
  56   if (!should_log()) {
  57     return;
  58   }
  59 
  60   double timestamp = fetch_timestamp();
  61   MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
  62   int index = compute_log_index();
  63   _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
  64   _records[index].timestamp = timestamp;
  65   _records[index].data.is_before = before;
  66   stringStream st(_records[index].data.buffer(), _records[index].data.size());
  67   if (before) {
  68     Universe::print_heap_before_gc(&st, true);
  69   } else {
  70     Universe::print_heap_after_gc(&st, true);
  71   }
  72 }
  73 
  74 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
  75   size_t capacity_in_words = capacity() / HeapWordSize;
  76 
  77   return VirtualSpaceSummary(
  78     reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
  79 }
  80 
  81 GCHeapSummary CollectedHeap::create_heap_summary() {
  82   VirtualSpaceSummary heap_space = create_heap_space_summary();
  83   return GCHeapSummary(heap_space, used());
  84 }
  85 
  86 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
  87   const MetaspaceSizes meta_space(
  88       MetaspaceAux::committed_bytes(),
  89       MetaspaceAux::used_bytes(),
  90       MetaspaceAux::reserved_bytes());
  91   const MetaspaceSizes data_space(
  92       MetaspaceAux::committed_bytes(Metaspace::NonClassType),
  93       MetaspaceAux::used_bytes(Metaspace::NonClassType),
  94       MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
  95   const MetaspaceSizes class_space(
  96       MetaspaceAux::committed_bytes(Metaspace::ClassType),
  97       MetaspaceAux::used_bytes(Metaspace::ClassType),
  98       MetaspaceAux::reserved_bytes(Metaspace::ClassType));
  99 
 100   const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
 101     MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
 102   const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
 103     MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
 104 
 105   return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
 106                           ms_chunk_free_list_summary, class_chunk_free_list_summary);
 107 }
 108 
 109 void CollectedHeap::print_heap_before_gc() {
 110   if (PrintHeapAtGC) {
 111     Universe::print_heap_before_gc();
 112   }
 113   if (_gc_heap_log != NULL) {
 114     _gc_heap_log->log_heap_before();
 115   }
 116 }
 117 
 118 void CollectedHeap::print_heap_after_gc() {
 119   if (PrintHeapAtGC) {
 120     Universe::print_heap_after_gc();
 121   }
 122   if (_gc_heap_log != NULL) {
 123     _gc_heap_log->log_heap_after();
 124   }
 125 }
 126 
 127 void CollectedHeap::register_nmethod(nmethod* nm) {
 128   assert_locked_or_safepoint(CodeCache_lock);
 129 }
 130 
 131 void CollectedHeap::unregister_nmethod(nmethod* nm) {
 132   assert_locked_or_safepoint(CodeCache_lock);
 133 }
 134 
 135 void CollectedHeap::trace_heap(GCWhen::Type when, GCTracer* gc_tracer) {
 136   const GCHeapSummary& heap_summary = create_heap_summary();
 137   gc_tracer->report_gc_heap_summary(when, heap_summary);
 138 
 139   const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
 140   gc_tracer->report_metaspace_summary(when, metaspace_summary);
 141 }
 142 
 143 void CollectedHeap::trace_heap_before_gc(GCTracer* gc_tracer) {
 144   trace_heap(GCWhen::BeforeGC, gc_tracer);
 145 }
 146 
 147 void CollectedHeap::trace_heap_after_gc(GCTracer* gc_tracer) {
 148   trace_heap(GCWhen::AfterGC, gc_tracer);
 149 }
 150 
 151 // Memory state functions.
 152 
 153 
 154 CollectedHeap::CollectedHeap() : _n_par_threads(0)
 155 {
 156   const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
 157   const size_t elements_per_word = HeapWordSize / sizeof(jint);
 158   _filler_array_max_size = align_object_size(filler_array_hdr_size() +
 159                                              max_len / elements_per_word);
 160 
 161   _barrier_set = NULL;
 162   _is_gc_active = false;
 163   _total_collections = _total_full_collections = 0;
 164   _gc_cause = _gc_lastcause = GCCause::_no_gc;
 165   NOT_PRODUCT(_promotion_failure_alot_count = 0;)
 166   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
 167 
 168   if (UsePerfData) {
 169     EXCEPTION_MARK;
 170 
 171     // create the gc cause jvmstat counters
 172     _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
 173                              80, GCCause::to_string(_gc_cause), CHECK);
 174 
 175     _perf_gc_lastcause =
 176                 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
 177                              80, GCCause::to_string(_gc_lastcause), CHECK);
 178   }
 179   _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
 180   // Create the ring log
 181   if (LogEvents) {
 182     _gc_heap_log = new GCHeapLog();
 183   } else {
 184     _gc_heap_log = NULL;
 185   }
 186 }
 187 
 188 // This interface assumes that it's being called by the
 189 // vm thread. It collects the heap assuming that the
 190 // heap lock is already held and that we are executing in
 191 // the context of the vm thread.
 192 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
 193   assert(Thread::current()->is_VM_thread(), "Precondition#1");
 194   assert(Heap_lock->is_locked(), "Precondition#2");
 195   GCCauseSetter gcs(this, cause);
 196   switch (cause) {
 197     case GCCause::_heap_inspection:
 198     case GCCause::_heap_dump:
 199     case GCCause::_metadata_GC_threshold : {
 200       HandleMark hm;
 201       do_full_collection(false);        // don't clear all soft refs
 202       break;
 203     }
 204     case GCCause::_last_ditch_collection: {
 205       HandleMark hm;
 206       do_full_collection(true);         // do clear all soft refs
 207       break;
 208     }
 209     default:
 210       ShouldNotReachHere(); // Unexpected use of this function
 211   }
 212 }
 213 
 214 void CollectedHeap::pre_initialize() {
 215   // Used for ReduceInitialCardMarks (when COMPILER2 is used);
 216   // otherwise remains unused.
 217 #ifdef COMPILER2
 218   _defer_initial_card_mark =    ReduceInitialCardMarks && can_elide_tlab_store_barriers()
 219                              && (DeferInitialCardMark || card_mark_must_follow_store());
 220 #else
 221   assert(_defer_initial_card_mark == false, "Who would set it?");
 222 #endif
 223 }
 224 
 225 #ifndef PRODUCT
 226 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
 227   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 228     for (size_t slot = 0; slot < size; slot += 1) {
 229       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
 230              "Found badHeapWordValue in post-allocation check");
 231     }
 232   }
 233 }
 234 
 235 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
 236   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 237     for (size_t slot = 0; slot < size; slot += 1) {
 238       assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
 239              "Found non badHeapWordValue in pre-allocation check");
 240     }
 241   }
 242 }
 243 #endif // PRODUCT
 244 
 245 #ifdef ASSERT
 246 void CollectedHeap::check_for_valid_allocation_state() {
 247   Thread *thread = Thread::current();
 248   // How to choose between a pending exception and a potential
 249   // OutOfMemoryError?  Don't allow pending exceptions.
 250   // This is a VM policy failure, so how do we exhaustively test it?
 251   assert(!thread->has_pending_exception(),
 252          "shouldn't be allocating with pending exception");
 253   if (StrictSafepointChecks) {
 254     assert(thread->allow_allocation(),
 255            "Allocation done by thread for which allocation is blocked "
 256            "by No_Allocation_Verifier!");
 257     // Allocation of an oop can always invoke a safepoint,
 258     // hence, the true argument
 259     thread->check_for_valid_safepoint_state(true);
 260   }
 261 }
 262 #endif
 263 
 264 HeapWord* CollectedHeap::allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size) {
 265 
 266   // Retain tlab and allocate object in shared space if
 267   // the amount free in the tlab is too large to discard.
 268   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
 269     thread->tlab().record_slow_allocation(size);
 270     return NULL;
 271   }
 272 
 273   // Discard tlab and allocate a new one.
 274   // To minimize fragmentation, the last TLAB may be smaller than the rest.
 275   size_t new_tlab_size = thread->tlab().compute_size(size);
 276 
 277   thread->tlab().clear_before_allocation();
 278 
 279   if (new_tlab_size == 0) {
 280     return NULL;
 281   }
 282 
 283   // Allocate a new TLAB...
 284   HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
 285   if (obj == NULL) {
 286     return NULL;
 287   }
 288 
 289   if (ZeroTLAB) {
 290     // ..and clear it.
 291     Copy::zero_to_words(obj, new_tlab_size);
 292   } else {
 293     // ...and zap just allocated object.
 294 #ifdef ASSERT
 295     // Skip mangling the space corresponding to the object header to
 296     // ensure that the returned space is not considered parsable by
 297     // any concurrent GC thread.
 298     size_t hdr_size = oopDesc::header_size();
 299     Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
 300 #endif // ASSERT
 301   }
 302   thread->tlab().fill(obj, obj + size, new_tlab_size);
 303   return obj;
 304 }
 305 
 306 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
 307   MemRegion deferred = thread->deferred_card_mark();
 308   if (!deferred.is_empty()) {
 309     assert(_defer_initial_card_mark, "Otherwise should be empty");
 310     {
 311       // Verify that the storage points to a parsable object in heap
 312       DEBUG_ONLY(oop old_obj = oop(deferred.start());)
 313       assert(is_in(old_obj), "Not in allocated heap");
 314       assert(!can_elide_initializing_store_barrier(old_obj),
 315              "Else should have been filtered in new_store_pre_barrier()");
 316       assert(old_obj->is_oop(true), "Not an oop");
 317       assert(deferred.word_size() == (size_t)(old_obj->size()),
 318              "Mismatch: multiple objects?");
 319     }
 320     BarrierSet* bs = barrier_set();
 321     assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
 322     bs->write_region(deferred);
 323     // "Clear" the deferred_card_mark field
 324     thread->set_deferred_card_mark(MemRegion());
 325   }
 326   assert(thread->deferred_card_mark().is_empty(), "invariant");
 327 }
 328 
 329 size_t CollectedHeap::max_tlab_size() const {
 330   // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
 331   // This restriction could be removed by enabling filling with multiple arrays.
 332   // If we compute that the reasonable way as
 333   //    header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
 334   // we'll overflow on the multiply, so we do the divide first.
 335   // We actually lose a little by dividing first,
 336   // but that just makes the TLAB  somewhat smaller than the biggest array,
 337   // which is fine, since we'll be able to fill that.
 338   size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
 339               sizeof(jint) *
 340               ((juint) max_jint / (size_t) HeapWordSize);
 341   return align_size_down(max_int_size, MinObjAlignment);
 342 }
 343 
 344 // Helper for ReduceInitialCardMarks. For performance,
 345 // compiled code may elide card-marks for initializing stores
 346 // to a newly allocated object along the fast-path. We
 347 // compensate for such elided card-marks as follows:
 348 // (a) Generational, non-concurrent collectors, such as
 349 //     GenCollectedHeap(ParNew,DefNew,Tenured) and
 350 //     ParallelScavengeHeap(ParallelGC, ParallelOldGC)
 351 //     need the card-mark if and only if the region is
 352 //     in the old gen, and do not care if the card-mark
 353 //     succeeds or precedes the initializing stores themselves,
 354 //     so long as the card-mark is completed before the next
 355 //     scavenge. For all these cases, we can do a card mark
 356 //     at the point at which we do a slow path allocation
 357 //     in the old gen, i.e. in this call.
 358 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
 359 //     in addition that the card-mark for an old gen allocated
 360 //     object strictly follow any associated initializing stores.
 361 //     In these cases, the memRegion remembered below is
 362 //     used to card-mark the entire region either just before the next
 363 //     slow-path allocation by this thread or just before the next scavenge or
 364 //     CMS-associated safepoint, whichever of these events happens first.
 365 //     (The implicit assumption is that the object has been fully
 366 //     initialized by this point, a fact that we assert when doing the
 367 //     card-mark.)
 368 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
 369 //     G1 concurrent marking is in progress an SATB (pre-write-)barrier is
 370 //     is used to remember the pre-value of any store. Initializing
 371 //     stores will not need this barrier, so we need not worry about
 372 //     compensating for the missing pre-barrier here. Turning now
 373 //     to the post-barrier, we note that G1 needs a RS update barrier
 374 //     which simply enqueues a (sequence of) dirty cards which may
 375 //     optionally be refined by the concurrent update threads. Note
 376 //     that this barrier need only be applied to a non-young write,
 377 //     but, like in CMS, because of the presence of concurrent refinement
 378 //     (much like CMS' precleaning), must strictly follow the oop-store.
 379 //     Thus, using the same protocol for maintaining the intended
 380 //     invariants turns out, serendepitously, to be the same for both
 381 //     G1 and CMS.
 382 //
 383 // For any future collector, this code should be reexamined with
 384 // that specific collector in mind, and the documentation above suitably
 385 // extended and updated.
 386 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
 387   // If a previous card-mark was deferred, flush it now.
 388   flush_deferred_store_barrier(thread);
 389   if (can_elide_initializing_store_barrier(new_obj)) {
 390     // The deferred_card_mark region should be empty
 391     // following the flush above.
 392     assert(thread->deferred_card_mark().is_empty(), "Error");
 393   } else {
 394     MemRegion mr((HeapWord*)new_obj, new_obj->size());
 395     assert(!mr.is_empty(), "Error");
 396     if (_defer_initial_card_mark) {
 397       // Defer the card mark
 398       thread->set_deferred_card_mark(mr);
 399     } else {
 400       // Do the card mark
 401       BarrierSet* bs = barrier_set();
 402       assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
 403       bs->write_region(mr);
 404     }
 405   }
 406   return new_obj;
 407 }
 408 
 409 size_t CollectedHeap::filler_array_hdr_size() {
 410   return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
 411 }
 412 
 413 size_t CollectedHeap::filler_array_min_size() {
 414   return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
 415 }
 416 
 417 #ifdef ASSERT
 418 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
 419 {
 420   assert(words >= min_fill_size(), "too small to fill");
 421   assert(words % MinObjAlignment == 0, "unaligned size");
 422   assert(Universe::heap()->is_in_reserved(start), "not in heap");
 423   assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
 424 }
 425 
 426 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
 427 {
 428   if (ZapFillerObjects && zap) {
 429     Copy::fill_to_words(start + filler_array_hdr_size(),
 430                         words - filler_array_hdr_size(), 0XDEAFBABE);
 431   }
 432 }
 433 #endif // ASSERT
 434 
 435 void
 436 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
 437 {
 438   assert(words >= filler_array_min_size(), "too small for an array");
 439   assert(words <= filler_array_max_size(), "too big for a single object");
 440 
 441   const size_t payload_size = words - filler_array_hdr_size();
 442   const size_t len = payload_size * HeapWordSize / sizeof(jint);
 443   assert((int)len >= 0, err_msg("size too large " SIZE_FORMAT " becomes %d", words, (int)len));
 444 
 445   // Set the length first for concurrent GC.
 446   ((arrayOop)start)->set_length((int)len);
 447   post_allocation_setup_common(Universe::intArrayKlassObj(), start);
 448   DEBUG_ONLY(zap_filler_array(start, words, zap);)
 449 }
 450 
 451 void
 452 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
 453 {
 454   assert(words <= filler_array_max_size(), "too big for a single object");
 455 
 456   if (words >= filler_array_min_size()) {
 457     fill_with_array(start, words, zap);
 458   } else if (words > 0) {
 459     assert(words == min_fill_size(), "unaligned size");
 460     post_allocation_setup_common(SystemDictionary::Object_klass(), start);
 461   }
 462 }
 463 
 464 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
 465 {
 466   DEBUG_ONLY(fill_args_check(start, words);)
 467   HandleMark hm;  // Free handles before leaving.
 468   fill_with_object_impl(start, words, zap);
 469 }
 470 
 471 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
 472 {
 473   DEBUG_ONLY(fill_args_check(start, words);)
 474   HandleMark hm;  // Free handles before leaving.
 475 
 476 #ifdef _LP64
 477   // A single array can fill ~8G, so multiple objects are needed only in 64-bit.
 478   // First fill with arrays, ensuring that any remaining space is big enough to
 479   // fill.  The remainder is filled with a single object.
 480   const size_t min = min_fill_size();
 481   const size_t max = filler_array_max_size();
 482   while (words > max) {
 483     const size_t cur = words - max >= min ? max : max - min;
 484     fill_with_array(start, cur, zap);
 485     start += cur;
 486     words -= cur;
 487   }
 488 #endif
 489 
 490   fill_with_object_impl(start, words, zap);
 491 }
 492 
 493 void CollectedHeap::post_initialize() {
 494   collector_policy()->post_heap_initialize();
 495 }
 496 
 497 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
 498   guarantee(false, "thread-local allocation buffers not supported");
 499   return NULL;
 500 }
 501 
 502 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
 503   // The second disjunct in the assertion below makes a concession
 504   // for the start-up verification done while the VM is being
 505   // created. Callers be careful that you know that mutators
 506   // aren't going to interfere -- for instance, this is permissible
 507   // if we are still single-threaded and have either not yet
 508   // started allocating (nothing much to verify) or we have
 509   // started allocating but are now a full-fledged JavaThread
 510   // (and have thus made our TLAB's) available for filling.
 511   assert(SafepointSynchronize::is_at_safepoint() ||
 512          !is_init_completed(),
 513          "Should only be called at a safepoint or at start-up"
 514          " otherwise concurrent mutator activity may make heap "
 515          " unparsable again");
 516   const bool use_tlab = UseTLAB;
 517   const bool deferred = _defer_initial_card_mark;
 518   // The main thread starts allocating via a TLAB even before it
 519   // has added itself to the threads list at vm boot-up.
 520   assert(!use_tlab || Threads::first() != NULL,
 521          "Attempt to fill tlabs before main thread has been added"
 522          " to threads list is doomed to failure!");
 523   for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 524      if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
 525 #ifdef COMPILER2
 526      // The deferred store barriers must all have been flushed to the
 527      // card-table (or other remembered set structure) before GC starts
 528      // processing the card-table (or other remembered set).
 529      if (deferred) flush_deferred_store_barrier(thread);
 530 #else
 531      assert(!deferred, "Should be false");
 532      assert(thread->deferred_card_mark().is_empty(), "Should be empty");
 533 #endif
 534   }
 535 }
 536 
 537 void CollectedHeap::accumulate_statistics_all_tlabs() {
 538   if (UseTLAB) {
 539     assert(SafepointSynchronize::is_at_safepoint() ||
 540          !is_init_completed(),
 541          "should only accumulate statistics on tlabs at safepoint");
 542 
 543     ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
 544   }
 545 }
 546 
 547 void CollectedHeap::resize_all_tlabs() {
 548   if (UseTLAB) {
 549     assert(SafepointSynchronize::is_at_safepoint() ||
 550          !is_init_completed(),
 551          "should only resize tlabs at safepoint");
 552 
 553     ThreadLocalAllocBuffer::resize_all_tlabs();
 554   }
 555 }
 556 
 557 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
 558   if (HeapDumpBeforeFullGC) {
 559     GCTraceTime tt("Heap Dump (before full gc): ", PrintGCDetails, false, timer, GCId::create());
 560     // We are doing a "major" collection and a heap dump before
 561     // major collection has been requested.
 562     HeapDumper::dump_heap();
 563   }
 564   if (PrintClassHistogramBeforeFullGC) {
 565     GCTraceTime tt("Class Histogram (before full gc): ", PrintGCDetails, true, timer, GCId::create());
 566     VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
 567     inspector.doit();
 568   }
 569 }
 570 
 571 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
 572   if (HeapDumpAfterFullGC) {
 573     GCTraceTime tt("Heap Dump (after full gc): ", PrintGCDetails, false, timer, GCId::create());
 574     HeapDumper::dump_heap();
 575   }
 576   if (PrintClassHistogramAfterFullGC) {
 577     GCTraceTime tt("Class Histogram (after full gc): ", PrintGCDetails, true, timer, GCId::create());
 578     VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
 579     inspector.doit();
 580   }
 581 }
 582 
 583 /////////////// Unit tests ///////////////
 584 
 585 #ifndef PRODUCT
 586 void CollectedHeap::test_is_in() {
 587   CollectedHeap* heap = Universe::heap();
 588 
 589   uintptr_t epsilon    = (uintptr_t) MinObjAlignment;
 590   uintptr_t heap_start = (uintptr_t) heap->_reserved.start();
 591   uintptr_t heap_end   = (uintptr_t) heap->_reserved.end();
 592 
 593   // Test that NULL is not in the heap.
 594   assert(!heap->is_in(NULL), "NULL is unexpectedly in the heap");
 595 
 596   // Test that a pointer to before the heap start is reported as outside the heap.
 597   assert(heap_start >= ((uintptr_t)NULL + epsilon), "sanity");
 598   void* before_heap = (void*)(heap_start - epsilon);
 599   assert(!heap->is_in(before_heap),
 600       err_msg("before_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(before_heap)));
 601 
 602   // Test that a pointer to after the heap end is reported as outside the heap.
 603   assert(heap_end <= ((uintptr_t)-1 - epsilon), "sanity");
 604   void* after_heap = (void*)(heap_end + epsilon);
 605   assert(!heap->is_in(after_heap),
 606       err_msg("after_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(after_heap)));
 607 }
 608 #endif