C++ ParallelScavengeHeap::young_gen方法代码示例

void PSPromotionManager::initialize() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  _old_gen = heap->old_gen();
  _young_space = heap->young_gen()->to_space();

  assert(_manager_array == NULL, "Attempt to initialize twice");
  _manager_array = NEW_C_HEAP_ARRAY(PSPromotionManager*, ParallelGCThreads+1, mtGC);
  guarantee(_manager_array != NULL, "Could not initialize promotion manager");

  _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
  guarantee(_stack_array_depth != NULL, "Cound not initialize promotion manager");

  // Create and register the PSPromotionManager(s) for the worker threads.
  for(uint i=0; i<ParallelGCThreads; i++) {
    _manager_array[i] = new PSPromotionManager();
    guarantee(_manager_array[i] != NULL, "Could not create PSPromotionManager");
    stack_array_depth()->register_queue(i, _manager_array[i]->claimed_stack_depth());
  }

  // The VMThread gets its own PSPromotionManager, which is not available
  // for work stealing.
  _manager_array[ParallelGCThreads] = new PSPromotionManager();
  guarantee(_manager_array[ParallelGCThreads] != NULL, "Could not create PSPromotionManager");
}

inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
  if (check_to_space) {
    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
    return should_scavenge(p, heap->young_gen()->to_space());
  }
  return should_scavenge(p);
}

 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
   _to_space = heap->young_gen()->to_space();
   
   assert(_promotion_manager != NULL, "Sanity");
 }

void PSMarkSweep::allocate_stacks() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  PSYoungGen* young_gen = heap->young_gen();

  MutableSpace* to_space = young_gen->to_space();
  _preserved_marks = (PreservedMark*)to_space->top();
  _preserved_count = 0;

  // We want to calculate the size in bytes first.
  _preserved_count_max  = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
  // Now divide by the size of a PreservedMark
  _preserved_count_max /= sizeof(PreservedMark);

  _preserved_mark_stack = NULL;
  _preserved_oop_stack = NULL;

  _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);

  int size = SystemDictionary::number_of_classes() * 2;
  _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
  // (#klass/k)^2, for k ~ 10 appears a better setting, but this will have to do for
  // now until we investigate a more optimal setting.
  _revisit_mdo_stack   = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true);
}

// This method iterates over all objects in the young generation,
// unforwarding markOops. It then restores any preserved mark oops,
// and clears the _preserved_mark_stack.
void PSScavenge::clean_up_failed_promotion() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  PSYoungGen* young_gen = heap->young_gen();

  {
    ResourceMark rm;

    // Unforward all pointers in the young gen.
    PSPromotionFailedClosure unforward_closure;
    young_gen->object_iterate(&unforward_closure);

    if (PrintGC && Verbose) {
      gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size());
    }

    // Restore any saved marks.
    while (!_preserved_oop_stack.is_empty()) {
      oop obj      = _preserved_oop_stack.pop();
      markOop mark = _preserved_mark_stack.pop();
      obj->set_mark(mark);
    }

    // Clear the preserved mark and oop stack caches.
    _preserved_mark_stack.clear(true);
    _preserved_oop_stack.clear(true);
  }

  // Reset the PromotionFailureALot counters.
  NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
}

 CheckForUnmarkedObjects() {
   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
   _young_gen = heap->young_gen();
   _card_table = barrier_set_cast<CardTableExtension>(heap->barrier_set());
   // No point in asserting barrier set type here. Need to make CardTableExtension
   // a unique barrier set type.
 }

  CheckForUnmarkedObjects() {
    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
    assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

    _young_gen = heap->young_gen();
    _card_table = (CardTableExtension*)heap->barrier_set();
    // No point in asserting barrier set type here. Need to make CardTableExtension
    // a unique barrier set type.
  }

bool PSScavenge::should_attempt_scavenge() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
  PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
  
  if (UsePerfData) {
    counters->update_scavenge_skipped(not_skipped);
  }

  PSYoungGen* young_gen = heap->young_gen();
  PSOldGen* old_gen = heap->old_gen();

  if (!ScavengeWithObjectsInToSpace) {
    // Do not attempt to promote unless to_space is empty
    if (!young_gen->to_space()->is_empty()) {
      _consecutive_skipped_scavenges++;
      if (UsePerfData) {
	counters->update_scavenge_skipped(to_space_not_empty);
      }
      return false;
    }
  }

  // Test to see if the scavenge will likely fail.
  PSAdaptiveSizePolicy* policy = heap->size_policy();

  // A similar test is done in the policy's should_full_GC().  If this is
  // changed, decide if that test should also be changed.
  size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
  size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
  bool result = promotion_estimate < old_gen->free_in_bytes();

  if (PrintGCDetails && Verbose) {
    gclog_or_tty->print(result ? "  do scavenge: " : "  skip scavenge: ");
    gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
      " padded_average_promoted " SIZE_FORMAT
      " free in old gen " SIZE_FORMAT,
      (size_t) policy->average_promoted_in_bytes(),
      (size_t) policy->padded_average_promoted_in_bytes(),
      old_gen->free_in_bytes());
    if (young_gen->used_in_bytes() < 
        (size_t) policy->padded_average_promoted_in_bytes()) {
      gclog_or_tty->print_cr(" padded_promoted_average is greater"
	" than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
    }
  }

  if (result) {
    _consecutive_skipped_scavenges = 0;
  } else {
    _consecutive_skipped_scavenges++;
    if (UsePerfData) {
      counters->update_scavenge_skipped(promoted_too_large);
    }
  }
  return result;
}

bool PSYoungPromotionLAB::lab_is_valid(MemRegion lab) {
  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  MutableSpace* to_space = heap->young_gen()->to_space();
  MemRegion used = to_space->used_region();
  if (used.contains(lab)) {
    return true;
  }

  return false;
}

void PSPromotionManager::pre_scavenge() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  _young_space = heap->young_gen()->to_space();

  for(uint i=0; i<ParallelGCThreads+1; i++) {
    manager_array(i)->reset();
  }
}

void PSMarkSweepDecorator::advance_destination_decorator() {
  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();

  assert(_destination_decorator != NULL, "Sanity");

  PSMarkSweepDecorator* first = heap->old_gen()->object_mark_sweep();
  PSMarkSweepDecorator* second = heap->young_gen()->eden_mark_sweep();
  PSMarkSweepDecorator* third = heap->young_gen()->from_mark_sweep();
  PSMarkSweepDecorator* fourth = heap->young_gen()->to_mark_sweep();

  if ( _destination_decorator == first ) {
    _destination_decorator = second;
  } else if ( _destination_decorator == second ) {
    _destination_decorator = third;
  } else if ( _destination_decorator == third ) {
    _destination_decorator = fourth;
  } else {
    fatal("PSMarkSweep attempting to advance past last compaction area");
  }
}

bool PSYoungPromotionLAB::lab_is_valid(MemRegion lab) {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  MutableSpace* to_space = heap->young_gen()->to_space();
  MemRegion used = to_space->used_region();
  if (used.contains(lab)) {
    return true;
  }

  return false;
}

void PSOldGen::precompact() {
  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  // Reset start array first.
  _start_array.reset();

  object_mark_sweep()->precompact();

  // Now compact the young gen
  heap->young_gen()->precompact();
}

void PSMarkSweep::mark_sweep_phase4() {
  EventMark m("4 compact heap");
  GCTraceTime tm("phase 4", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id());

  // All pointers are now adjusted, move objects accordingly

  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  PSYoungGen* young_gen = heap->young_gen();
  PSOldGen* old_gen = heap->old_gen();

  old_gen->compact();
  young_gen->compact();
}

void PSMarkSweep::allocate_stacks() {
  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  PSYoungGen* young_gen = heap->young_gen();

  MutableSpace* to_space = young_gen->to_space();
  _preserved_marks = (PreservedMark*)to_space->top();
  _preserved_count = 0;

  // We want to calculate the size in bytes first.
  _preserved_count_max  = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
  // Now divide by the size of a PreservedMark
  _preserved_count_max /= sizeof(PreservedMark);
}