1 /*
  2  * Copyright (c) 2001, 2018, 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.hpp"
 29 #include "gc/shared/collectedHeap.hpp"
 30 #include "gc/shared/collectedHeap.inline.hpp"
 31 #include "gc/shared/gcLocker.inline.hpp"
 32 #include "gc/shared/gcHeapSummary.hpp"
 33 #include "gc/shared/gcTrace.hpp"
 34 #include "gc/shared/gcTraceTime.inline.hpp"
 35 #include "gc/shared/gcWhen.hpp"
 36 #include "gc/shared/vmGCOperations.hpp"
 37 #include "logging/log.hpp"
 38 #include "memory/metaspace.hpp"
 39 #include "memory/resourceArea.hpp"
 40 #include "oops/instanceMirrorKlass.hpp"
 41 #include "oops/oop.inline.hpp"
 42 #include "runtime/handles.inline.hpp"
 43 #include "runtime/init.hpp"
 44 #include "runtime/thread.inline.hpp"
 45 #include "runtime/threadSMR.hpp"
 46 #include "runtime/vmThread.hpp"
 47 #include "services/heapDumper.hpp"
 48 #include "utilities/align.hpp"
 49 
 50 class ClassLoaderData;
 51 
 52 #ifdef ASSERT
 53 int CollectedHeap::_fire_out_of_memory_count = 0;
 54 #endif
 55 
 56 size_t CollectedHeap::_filler_array_max_size = 0;
 57 
 58 template <>
 59 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
 60   st->print_cr("GC heap %s", m.is_before ? "before" : "after");
 61   st->print_raw(m);
 62 }
 63 
 64 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
 65   if (!should_log()) {
 66     return;
 67   }
 68 
 69   double timestamp = fetch_timestamp();
 70   MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
 71   int index = compute_log_index();
 72   _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
 73   _records[index].timestamp = timestamp;
 74   _records[index].data.is_before = before;
 75   stringStream st(_records[index].data.buffer(), _records[index].data.size());
 76 
 77   st.print_cr("{Heap %s GC invocations=%u (full %u):",
 78                  before ? "before" : "after",
 79                  heap->total_collections(),
 80                  heap->total_full_collections());
 81 
 82   heap->print_on(&st);
 83   st.print_cr("}");
 84 }
 85 
 86 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
 87   size_t capacity_in_words = capacity() / HeapWordSize;
 88 
 89   return VirtualSpaceSummary(
 90     reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
 91 }
 92 
 93 GCHeapSummary CollectedHeap::create_heap_summary() {
 94   VirtualSpaceSummary heap_space = create_heap_space_summary();
 95   return GCHeapSummary(heap_space, used());
 96 }
 97 
 98 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
 99   const MetaspaceSizes meta_space(
100       MetaspaceUtils::committed_bytes(),
101       MetaspaceUtils::used_bytes(),
102       MetaspaceUtils::reserved_bytes());
103   const MetaspaceSizes data_space(
104       MetaspaceUtils::committed_bytes(Metaspace::NonClassType),
105       MetaspaceUtils::used_bytes(Metaspace::NonClassType),
106       MetaspaceUtils::reserved_bytes(Metaspace::NonClassType));
107   const MetaspaceSizes class_space(
108       MetaspaceUtils::committed_bytes(Metaspace::ClassType),
109       MetaspaceUtils::used_bytes(Metaspace::ClassType),
110       MetaspaceUtils::reserved_bytes(Metaspace::ClassType));
111 
112   const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
113     MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);
114   const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
115     MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);
116 
117   return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
118                           ms_chunk_free_list_summary, class_chunk_free_list_summary);
119 }
120 
121 void CollectedHeap::print_heap_before_gc() {
122   Universe::print_heap_before_gc();
123   if (_gc_heap_log != NULL) {
124     _gc_heap_log->log_heap_before(this);
125   }
126 }
127 
128 void CollectedHeap::print_heap_after_gc() {
129   Universe::print_heap_after_gc();
130   if (_gc_heap_log != NULL) {
131     _gc_heap_log->log_heap_after(this);
132   }
133 }
134 
135 void CollectedHeap::print_on_error(outputStream* st) const {
136   st->print_cr("Heap:");
137   print_extended_on(st);
138   st->cr();
139 
140   BarrierSet::barrier_set()->print_on(st);
141 }
142 
143 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
144   const GCHeapSummary& heap_summary = create_heap_summary();
145   gc_tracer->report_gc_heap_summary(when, heap_summary);
146 
147   const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
148   gc_tracer->report_metaspace_summary(when, metaspace_summary);
149 }
150 
151 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
152   trace_heap(GCWhen::BeforeGC, gc_tracer);
153 }
154 
155 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
156   trace_heap(GCWhen::AfterGC, gc_tracer);
157 }
158 
159 // WhiteBox API support for concurrent collectors.  These are the
160 // default implementations, for collectors which don't support this
161 // feature.
162 bool CollectedHeap::supports_concurrent_phase_control() const {
163   return false;
164 }
165 
166 const char* const* CollectedHeap::concurrent_phases() const {
167   static const char* const result[] = { NULL };
168   return result;
169 }
170 
171 bool CollectedHeap::request_concurrent_phase(const char* phase) {
172   return false;
173 }
174 
175 bool CollectedHeap::is_oop(oop object) const {
176   if (!check_obj_alignment(object)) {
177     return false;
178   }
179 
180   if (!is_in_reserved(object)) {
181     return false;
182   }
183 
184   if (is_in_reserved(object->klass_or_null())) {
185     return false;
186   }
187 
188   return true;
189 }
190 
191 // Memory state functions.
192 
193 
194 CollectedHeap::CollectedHeap() :
195   _is_gc_active(false),
196   _total_collections(0),
197   _total_full_collections(0),
198   _gc_cause(GCCause::_no_gc),
199   _gc_lastcause(GCCause::_no_gc)
200 {
201   const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
202   const size_t elements_per_word = HeapWordSize / sizeof(jint);
203   _filler_array_max_size = align_object_size(filler_array_hdr_size() +
204                                              max_len / elements_per_word);
205 
206   NOT_PRODUCT(_promotion_failure_alot_count = 0;)
207   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
208 
209   if (UsePerfData) {
210     EXCEPTION_MARK;
211 
212     // create the gc cause jvmstat counters
213     _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
214                              80, GCCause::to_string(_gc_cause), CHECK);
215 
216     _perf_gc_lastcause =
217                 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
218                              80, GCCause::to_string(_gc_lastcause), CHECK);
219   }
220 
221   // Create the ring log
222   if (LogEvents) {
223     _gc_heap_log = new GCHeapLog();
224   } else {
225     _gc_heap_log = NULL;
226   }
227 }
228 
229 // This interface assumes that it's being called by the
230 // vm thread. It collects the heap assuming that the
231 // heap lock is already held and that we are executing in
232 // the context of the vm thread.
233 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
234   assert(Thread::current()->is_VM_thread(), "Precondition#1");
235   assert(Heap_lock->is_locked(), "Precondition#2");
236   GCCauseSetter gcs(this, cause);
237   switch (cause) {
238     case GCCause::_heap_inspection:
239     case GCCause::_heap_dump:
240     case GCCause::_metadata_GC_threshold : {
241       HandleMark hm;
242       do_full_collection(false);        // don't clear all soft refs
243       break;
244     }
245     case GCCause::_metadata_GC_clear_soft_refs: {
246       HandleMark hm;
247       do_full_collection(true);         // do clear all soft refs
248       break;
249     }
250     default:
251       ShouldNotReachHere(); // Unexpected use of this function
252   }
253 }
254 
255 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
256                                                             size_t word_size,
257                                                             Metaspace::MetadataType mdtype) {
258   uint loop_count = 0;
259   uint gc_count = 0;
260   uint full_gc_count = 0;
261 
262   assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
263 
264   do {
265     MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
266     if (result != NULL) {
267       return result;
268     }
269 
270     if (GCLocker::is_active_and_needs_gc()) {
271       // If the GCLocker is active, just expand and allocate.
272       // If that does not succeed, wait if this thread is not
273       // in a critical section itself.
274       result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
275       if (result != NULL) {
276         return result;
277       }
278       JavaThread* jthr = JavaThread::current();
279       if (!jthr->in_critical()) {
280         // Wait for JNI critical section to be exited
281         GCLocker::stall_until_clear();
282         // The GC invoked by the last thread leaving the critical
283         // section will be a young collection and a full collection
284         // is (currently) needed for unloading classes so continue
285         // to the next iteration to get a full GC.
286         continue;
287       } else {
288         if (CheckJNICalls) {
289           fatal("Possible deadlock due to allocating while"
290                 " in jni critical section");
291         }
292         return NULL;
293       }
294     }
295 
296     {  // Need lock to get self consistent gc_count's
297       MutexLocker ml(Heap_lock);
298       gc_count      = Universe::heap()->total_collections();
299       full_gc_count = Universe::heap()->total_full_collections();
300     }
301 
302     // Generate a VM operation
303     VM_CollectForMetadataAllocation op(loader_data,
304                                        word_size,
305                                        mdtype,
306                                        gc_count,
307                                        full_gc_count,
308                                        GCCause::_metadata_GC_threshold);
309     VMThread::execute(&op);
310 
311     // If GC was locked out, try again. Check before checking success because the
312     // prologue could have succeeded and the GC still have been locked out.
313     if (op.gc_locked()) {
314       continue;
315     }
316 
317     if (op.prologue_succeeded()) {
318       return op.result();
319     }
320     loop_count++;
321     if ((QueuedAllocationWarningCount > 0) &&
322         (loop_count % QueuedAllocationWarningCount == 0)) {
323       log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
324                             " size=" SIZE_FORMAT, loop_count, word_size);
325     }
326   } while (true);  // Until a GC is done
327 }
328 
329 #ifndef PRODUCT
330 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
331   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
332     for (size_t slot = 0; slot < size; slot += 1) {
333       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
334              "Found badHeapWordValue in post-allocation check");
335     }
336   }
337 }
338 
339 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
340   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
341     for (size_t slot = 0; slot < size; slot += 1) {
342       assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
343              "Found non badHeapWordValue in pre-allocation check");
344     }
345   }
346 }
347 #endif // PRODUCT
348 
349 #ifdef ASSERT
350 void CollectedHeap::check_for_valid_allocation_state() {
351   Thread *thread = Thread::current();
352   // How to choose between a pending exception and a potential
353   // OutOfMemoryError?  Don't allow pending exceptions.
354   // This is a VM policy failure, so how do we exhaustively test it?
355   assert(!thread->has_pending_exception(),
356          "shouldn't be allocating with pending exception");
357   if (StrictSafepointChecks) {
358     assert(thread->allow_allocation(),
359            "Allocation done by thread for which allocation is blocked "
360            "by No_Allocation_Verifier!");
361     // Allocation of an oop can always invoke a safepoint,
362     // hence, the true argument
363     thread->check_for_valid_safepoint_state(true);
364   }
365 }
366 #endif
367 
368 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
369 
370   // Retain tlab and allocate object in shared space if
371   // the amount free in the tlab is too large to discard.
372   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
373     thread->tlab().record_slow_allocation(size);
374     return NULL;
375   }
376 
377   // Discard tlab and allocate a new one.
378   // To minimize fragmentation, the last TLAB may be smaller than the rest.
379   size_t new_tlab_size = thread->tlab().compute_size(size);
380 
381   thread->tlab().clear_before_allocation();
382 
383   if (new_tlab_size == 0) {
384     return NULL;
385   }
386 
387   // Allocate a new TLAB requesting new_tlab_size. Any size
388   // between minimal and new_tlab_size is accepted.
389   size_t actual_tlab_size = 0;
390   size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
391   HeapWord* obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
392   if (obj == NULL) {
393     assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
394            min_tlab_size, new_tlab_size, actual_tlab_size);
395     return NULL;
396   }
397   assert(actual_tlab_size != 0, "Allocation succeeded but actual size not updated. obj at: " PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
398          p2i(obj), min_tlab_size, new_tlab_size);
399 
400   AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, thread);
401 
402   if (ZeroTLAB) {
403     // ..and clear it.
404     Copy::zero_to_words(obj, actual_tlab_size);
405   } else {
406     // ...and zap just allocated object.
407 #ifdef ASSERT
408     // Skip mangling the space corresponding to the object header to
409     // ensure that the returned space is not considered parsable by
410     // any concurrent GC thread.
411     size_t hdr_size = oopDesc::header_size();
412     Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
413 #endif // ASSERT
414   }
415   thread->tlab().fill(obj, obj + size, actual_tlab_size);
416   return obj;
417 }
418 
419 size_t CollectedHeap::max_tlab_size() const {
420   // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
421   // This restriction could be removed by enabling filling with multiple arrays.
422   // If we compute that the reasonable way as
423   //    header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
424   // we'll overflow on the multiply, so we do the divide first.
425   // We actually lose a little by dividing first,
426   // but that just makes the TLAB  somewhat smaller than the biggest array,
427   // which is fine, since we'll be able to fill that.
428   size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
429               sizeof(jint) *
430               ((juint) max_jint / (size_t) HeapWordSize);
431   return align_down(max_int_size, MinObjAlignment);
432 }
433 
434 size_t CollectedHeap::filler_array_hdr_size() {
435   return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
436 }
437 
438 size_t CollectedHeap::filler_array_min_size() {
439   return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
440 }
441 
442 #ifdef ASSERT
443 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
444 {
445   assert(words >= min_fill_size(), "too small to fill");
446   assert(is_object_aligned(words), "unaligned size");
447   assert(Universe::heap()->is_in_reserved(start), "not in heap");
448   assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
449 }
450 
451 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
452 {
453   if (ZapFillerObjects && zap) {
454     Copy::fill_to_words(start + filler_array_hdr_size(),
455                         words - filler_array_hdr_size(), 0XDEAFBABE);
456   }
457 }
458 #endif // ASSERT
459 
460 void
461 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
462 {
463   assert(words >= filler_array_min_size(), "too small for an array");
464   assert(words <= filler_array_max_size(), "too big for a single object");
465 
466   const size_t payload_size = words - filler_array_hdr_size();
467   const size_t len = payload_size * HeapWordSize / sizeof(jint);
468   assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
469 
470   // Set the length first for concurrent GC.
471   ((arrayOop)start)->set_length((int)len);
472   post_allocation_setup_common(Universe::intArrayKlassObj(), start);
473   DEBUG_ONLY(zap_filler_array(start, words, zap);)
474 }
475 
476 void
477 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
478 {
479   assert(words <= filler_array_max_size(), "too big for a single object");
480 
481   if (words >= filler_array_min_size()) {
482     fill_with_array(start, words, zap);
483   } else if (words > 0) {
484     assert(words == min_fill_size(), "unaligned size");
485     post_allocation_setup_common(SystemDictionary::Object_klass(), start);
486   }
487 }
488 
489 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
490 {
491   DEBUG_ONLY(fill_args_check(start, words);)
492   HandleMark hm;  // Free handles before leaving.
493   fill_with_object_impl(start, words, zap);
494 }
495 
496 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
497 {
498   DEBUG_ONLY(fill_args_check(start, words);)
499   HandleMark hm;  // Free handles before leaving.
500 
501   // Multiple objects may be required depending on the filler array maximum size. Fill
502   // the range up to that with objects that are filler_array_max_size sized. The
503   // remainder is filled with a single object.
504   const size_t min = min_fill_size();
505   const size_t max = filler_array_max_size();
506   while (words > max) {
507     const size_t cur = (words - max) >= min ? max : max - min;
508     fill_with_array(start, cur, zap);
509     start += cur;
510     words -= cur;
511   }
512 
513   fill_with_object_impl(start, words, zap);
514 }
515 
516 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
517                                            size_t requested_size,
518                                            size_t* actual_size) {
519   guarantee(false, "thread-local allocation buffers not supported");
520   return NULL;
521 }
522 
523 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
524   // The second disjunct in the assertion below makes a concession
525   // for the start-up verification done while the VM is being
526   // created. Callers be careful that you know that mutators
527   // aren't going to interfere -- for instance, this is permissible
528   // if we are still single-threaded and have either not yet
529   // started allocating (nothing much to verify) or we have
530   // started allocating but are now a full-fledged JavaThread
531   // (and have thus made our TLAB's) available for filling.
532   assert(SafepointSynchronize::is_at_safepoint() ||
533          !is_init_completed(),
534          "Should only be called at a safepoint or at start-up"
535          " otherwise concurrent mutator activity may make heap "
536          " unparsable again");
537   const bool use_tlab = UseTLAB;
538   // The main thread starts allocating via a TLAB even before it
539   // has added itself to the threads list at vm boot-up.
540   JavaThreadIteratorWithHandle jtiwh;
541   assert(!use_tlab || jtiwh.length() > 0,
542          "Attempt to fill tlabs before main thread has been added"
543          " to threads list is doomed to failure!");
544   BarrierSet *bs = BarrierSet::barrier_set();
545   for (; JavaThread *thread = jtiwh.next(); ) {
546      if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
547      bs->make_parsable(thread);
548   }
549 }
550 
551 void CollectedHeap::accumulate_statistics_all_tlabs() {
552   if (UseTLAB) {
553     assert(SafepointSynchronize::is_at_safepoint() ||
554          !is_init_completed(),
555          "should only accumulate statistics on tlabs at safepoint");
556 
557     ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
558   }
559 }
560 
561 void CollectedHeap::resize_all_tlabs() {
562   if (UseTLAB) {
563     assert(SafepointSynchronize::is_at_safepoint() ||
564          !is_init_completed(),
565          "should only resize tlabs at safepoint");
566 
567     ThreadLocalAllocBuffer::resize_all_tlabs();
568   }
569 }
570 
571 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
572   assert(timer != NULL, "timer is null");
573   if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
574     GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
575     HeapDumper::dump_heap();
576   }
577 
578   LogTarget(Trace, gc, classhisto) lt;
579   if (lt.is_enabled()) {
580     GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
581     ResourceMark rm;
582     LogStream ls(lt);
583     VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
584     inspector.doit();
585   }
586 }
587 
588 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
589   full_gc_dump(timer, true);
590 }
591 
592 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
593   full_gc_dump(timer, false);
594 }
595 
596 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
597   // It is important to do this in a way such that concurrent readers can't
598   // temporarily think something is in the heap.  (Seen this happen in asserts.)
599   _reserved.set_word_size(0);
600   _reserved.set_start(start);
601   _reserved.set_end(end);
602 }
603 
604 void CollectedHeap::post_initialize() {
605   initialize_serviceability();
606 }
607 
608 #ifndef PRODUCT
609 
610 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
611   // Access to count is not atomic; the value does not have to be exact.
612   if (PromotionFailureALot) {
613     const size_t gc_num = total_collections();
614     const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
615     if (elapsed_gcs >= PromotionFailureALotInterval) {
616       // Test for unsigned arithmetic wrap-around.
617       if (++*count >= PromotionFailureALotCount) {
618         *count = 0;
619         return true;
620       }
621     }
622   }
623   return false;
624 }
625 
626 bool CollectedHeap::promotion_should_fail() {
627   return promotion_should_fail(&_promotion_failure_alot_count);
628 }
629 
630 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
631   if (PromotionFailureALot) {
632     _promotion_failure_alot_gc_number = total_collections();
633     *count = 0;
634   }
635 }
636 
637 void CollectedHeap::reset_promotion_should_fail() {
638   reset_promotion_should_fail(&_promotion_failure_alot_count);
639 }
640 
641 #endif  // #ifndef PRODUCT
642 
643 bool CollectedHeap::supports_object_pinning() const {
644   return false;
645 }
646 
647 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
648   ShouldNotReachHere();
649   return NULL;
650 }
651 
652 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
653   ShouldNotReachHere();
654 }
655 
656 void CollectedHeap::deduplicate_string(oop str) {
657   // Do nothing, unless overridden in subclass.
658 }