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 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

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#ifndef SHARE_VM_GC_CMS_PARNEWGENERATION_HPP

#define SHARE_VM_GC_CMS_PARNEWGENERATION_HPP

#include "gc/cms/parOopClosures.hpp"

#include "gc/serial/defNewGeneration.hpp"

#include "gc/shared/copyFailedInfo.hpp"

#include "gc/shared/gcTrace.hpp"

#include "gc/shared/oopStorageParState.hpp"

#include "gc/shared/plab.hpp"

#include "gc/shared/preservedMarks.hpp"

#include "gc/shared/taskqueue.hpp"

#include "memory/padded.hpp"

class ChunkArray;

class CMSHeap;

class ParScanWithoutBarrierClosure;

class ParScanWithBarrierClosure;

class ParRootScanWithoutBarrierClosure;

class ParRootScanWithBarrierTwoGensClosure;

class ParEvacuateFollowersClosure;

class StrongRootsScope;

// It would be better if these types could be kept local to the .cpp file,

// but they must be here to allow ParScanClosure::do_oop_work to be defined

// in genOopClosures.inline.hpp.

typedef Padded<OopTaskQueue> ObjToScanQueue;

typedef GenericTaskQueueSet<ObjToScanQueue, mtGC> ObjToScanQueueSet;

class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure {

 private:

  ParScanWeakRefClosure* _par_cl;

 protected:

  template <class T> void do_oop_work(T* p);

 public:

  ParKeepAliveClosure(ParScanWeakRefClosure* cl);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

};

// The state needed by thread performing parallel young-gen collection.

class ParScanThreadState {

  friend class ParScanThreadStateSet;

 private:

  ObjToScanQueue *_work_queue;

  Stack<oop, mtGC>* const _overflow_stack;

  PreservedMarks* const _preserved_marks;

  PLAB _to_space_alloc_buffer;

  ParScanWithoutBarrierClosure         _to_space_closure; // scan_without_gc_barrier

  ParScanWithBarrierClosure            _old_gen_closure; // scan_with_gc_barrier

  ParRootScanWithoutBarrierClosure     _to_space_root_closure; // scan_root_without_gc_barrier

  // Will be passed to process_roots to set its generation.

  ParRootScanWithBarrierTwoGensClosure _older_gen_closure;

  // This closure will always be bound to the old gen; it will be used

  // in evacuate_followers.

  ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier

  ParEvacuateFollowersClosure          _evacuate_followers;

  DefNewGeneration::IsAliveClosure     _is_alive_closure;

  ParScanWeakRefClosure                _scan_weak_ref_closure;

  ParKeepAliveClosure                  _keep_alive_closure;

  Space* _to_space;

  Space* to_space() { return _to_space; }

  ParNewGeneration* _young_gen;

  ParNewGeneration* young_gen() const { return _young_gen; }

  Generation* _old_gen;

  Generation* old_gen() { return _old_gen; }

  HeapWord *_young_old_boundary;

  int _hash_seed;

  int _thread_num;

  AgeTable _ageTable;

  bool _to_space_full;

#if TASKQUEUE_STATS

  size_t _term_attempts;

  size_t _overflow_refills;

  size_t _overflow_refill_objs;

#endif // TASKQUEUE_STATS

  // Stats for promotion failure

  PromotionFailedInfo _promotion_failed_info;

  // Timing numbers.

  double _start;

  double _start_strong_roots;

  double _strong_roots_time;

  double _start_term;

  double _term_time;

  // Helper for trim_queues. Scans subset of an array and makes

  // remainder available for work stealing.

  void scan_partial_array_and_push_remainder(oop obj);

  // In support of CMS' parallel rescan of survivor space.

  ChunkArray* _survivor_chunk_array;

  ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; }

  void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size);

  ParScanThreadState(Space* to_space_, ParNewGeneration* gen_,

                     Generation* old_gen_, int thread_num_,

                     ObjToScanQueueSet* work_queue_set_,

                     Stack<oop, mtGC>* overflow_stacks_,

                     PreservedMarks* preserved_marks_,

                     size_t desired_plab_sz_,

                     ParallelTaskTerminator& term_);

 public:

  AgeTable* age_table() {return &_ageTable;}

  ObjToScanQueue* work_queue() { return _work_queue; }

  PreservedMarks* preserved_marks() const { return _preserved_marks; }

  PLAB* to_space_alloc_buffer() {

    return &_to_space_alloc_buffer;

  }

  ParEvacuateFollowersClosure&      evacuate_followers_closure() { return _evacuate_followers; }

  DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; }

  ParScanWeakRefClosure&            scan_weak_ref_closure() { return _scan_weak_ref_closure; }

  ParKeepAliveClosure&              keep_alive_closure() { return _keep_alive_closure; }

  ParScanClosure&                   older_gen_closure() { return _older_gen_closure; }

  ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; };

  // Decrease queue size below "max_size".

  void trim_queues(int max_size);

  // Private overflow stack usage

  Stack<oop, mtGC>* overflow_stack() { return _overflow_stack; }

  bool take_from_overflow_stack();

  void push_on_overflow_stack(oop p);

  // Is new_obj a candidate for scan_partial_array_and_push_remainder method.

  inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const;

  int* hash_seed()  { return &_hash_seed; }

  int  thread_num() { return _thread_num; }

  // Allocate a to-space block of size "sz", or else return NULL.

  HeapWord* alloc_in_to_space_slow(size_t word_sz);

  inline HeapWord* alloc_in_to_space(size_t word_sz);

  HeapWord* young_old_boundary() { return _young_old_boundary; }

  void set_young_old_boundary(HeapWord *boundary) {

    _young_old_boundary = boundary;

  }

  // Undo the most recent allocation ("obj", of "word_sz").

  void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz);

  // Promotion failure stats

  void register_promotion_failure(size_t sz) {

    _promotion_failed_info.register_copy_failure(sz);

  }

  PromotionFailedInfo& promotion_failed_info() {

    return _promotion_failed_info;

  }

  bool promotion_failed() {

    return _promotion_failed_info.has_failed();

  }

  void print_promotion_failure_size();

#if TASKQUEUE_STATS

  TaskQueueStats & taskqueue_stats() const { return _work_queue->stats; }

  size_t term_attempts() const             { return _term_attempts; }

  size_t overflow_refills() const          { return _overflow_refills; }

  size_t overflow_refill_objs() const      { return _overflow_refill_objs; }

  void note_term_attempt()                 { ++_term_attempts; }

  void note_overflow_refill(size_t objs)   {

    ++_overflow_refills; _overflow_refill_objs += objs;

  }

  void reset_stats();

#endif // TASKQUEUE_STATS

  void start_strong_roots() {

    _start_strong_roots = os::elapsedTime();

  }

  void end_strong_roots() {

    _strong_roots_time += (os::elapsedTime() - _start_strong_roots);

  }

  double strong_roots_time() const { return _strong_roots_time; }

  void start_term_time() {

    TASKQUEUE_STATS_ONLY(note_term_attempt());

    _start_term = os::elapsedTime();

  }

  void end_term_time() {

    _term_time += (os::elapsedTime() - _start_term);

  }

  double term_time() const { return _term_time; }

  double elapsed_time() const {

    return os::elapsedTime() - _start;

  }

};

class ParNewGenTask: public AbstractGangTask {

 private:

  ParNewGeneration*            _young_gen;

  Generation*                  _old_gen;

  HeapWord*                    _young_old_boundary;

  class ParScanThreadStateSet* _state_set;

  StrongRootsScope*            _strong_roots_scope;

  OopStorage::ParState<false, false> _par_state_string;

public:

  ParNewGenTask(ParNewGeneration*      young_gen,

                Generation*            old_gen,

                HeapWord*              young_old_boundary,

                ParScanThreadStateSet* state_set,

                StrongRootsScope*      strong_roots_scope);

  HeapWord* young_old_boundary() { return _young_old_boundary; }

  void work(uint worker_id);

};

class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure {

 protected:

  template <class T> void do_oop_work(T* p);

 public:

  KeepAliveClosure(ScanWeakRefClosure* cl);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

};

template <typename OopClosureType1, typename OopClosureType2>

class EvacuateFollowersClosureGeneral: public VoidClosure {

 private:

  CMSHeap* _heap;

  OopClosureType1* _scan_cur_or_nonheap;

  OopClosureType2* _scan_older;

 public:

  EvacuateFollowersClosureGeneral(CMSHeap* heap,

                                  OopClosureType1* cur,

                                  OopClosureType2* older);

  virtual void do_void();

};

// Closure for scanning ParNewGeneration.

// Same as ScanClosure, except does parallel GC barrier.

class ScanClosureWithParBarrier: public ScanClosure {

 protected:

  template <class T> void do_oop_work(T* p);

 public:

  ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

};

// Implements AbstractRefProcTaskExecutor for ParNew.

class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor {

 private:

  ParNewGeneration&      _young_gen;

  Generation&            _old_gen;

  ParScanThreadStateSet& _state_set;

 public:

  ParNewRefProcTaskExecutor(ParNewGeneration& young_gen,

                            Generation& old_gen,

                            ParScanThreadStateSet& state_set)

    : _young_gen(young_gen), _old_gen(old_gen), _state_set(state_set)

  { }

  // Executes a task using worker threads.

  // Switch to single threaded mode.

  virtual void set_single_threaded_mode();

};

// A Generation that does parallel young-gen collection.

class ParNewGeneration: public DefNewGeneration {

  friend class ParNewGenTask;

  friend class ParNewRefProcTask;

  friend class ParNewRefProcTaskExecutor;

  friend class ParScanThreadStateSet;

  friend class ParEvacuateFollowersClosure;

 private:

  // The per-worker-thread work queues

  ObjToScanQueueSet* _task_queues;

  // Per-worker-thread local overflow stacks

  Stack<oop, mtGC>* _overflow_stacks;

  // Desired size of survivor space plab's

  PLABStats _plab_stats;

  // A list of from-space images of to-be-scanned objects, threaded through

  // klass-pointers (klass information already copied to the forwarded

  // image.)  Manipulated with CAS.

  oopDesc* volatile _overflow_list;

  NOT_PRODUCT(ssize_t _num_par_pushes;)

  // This closure is used by the reference processor to filter out

  // references to live referent.

  DefNewGeneration::IsAliveClosure _is_alive_closure;

  // GC tracer that should be used during collection.

  ParNewTracer _gc_tracer;

  static oop real_forwardee_slow(oop obj);

  static void waste_some_time();

  void handle_promotion_failed(CMSHeap* gch, ParScanThreadStateSet& thread_state_set);

 protected:

  bool _survivor_overflow;

  bool survivor_overflow() { return _survivor_overflow; }

  void set_survivor_overflow(bool v) { _survivor_overflow = v; }

  void restore_preserved_marks();

 public:

  ParNewGeneration(ReservedSpace rs, size_t initial_byte_size);

  ~ParNewGeneration() {

    for (uint i = 0; i < ParallelGCThreads; i++)

        delete _task_queues->queue(i);

    delete _task_queues;

  }

  virtual void ref_processor_init();

  virtual Generation::Name kind()        { return Generation::ParNew; }

  virtual const char* name() const;

  virtual const char* short_name() const { return "ParNew"; }

  // override

  virtual bool refs_discovery_is_mt()     const {

    return ParallelGCThreads > 1;

  }

  // Make the collection virtual.

  virtual void collect(bool   full,

                       bool   clear_all_soft_refs,

                       size_t size,

                       bool   is_tlab);

  // This needs to be visible to the closure function.

  // "obj" is the object to be copied, "m" is a recent value of its mark

  // that must not contain a forwarding pointer (though one might be

  // inserted in "obj"s mark word by a parallel thread).

  oop copy_to_survivor_space(ParScanThreadState* par_scan_state,

                             oop obj, size_t obj_sz, markOop m);

  // in support of testing overflow code

  NOT_PRODUCT(int _overflow_counter;)

  NOT_PRODUCT(bool should_simulate_overflow();)

  // Accessor for overflow list

  oop overflow_list() { return _overflow_list; }

  // Push the given (from-space) object on the global overflow list.

  void push_on_overflow_list(oop from_space_obj, ParScanThreadState* par_scan_state);

  // If the global overflow list is non-empty, move some tasks from it

  // onto "work_q" (which need not be empty).  No more than 1/4 of the

  // available space on "work_q" is used.

  bool take_from_overflow_list(ParScanThreadState* par_scan_state);

  bool take_from_overflow_list_work(ParScanThreadState* par_scan_state);

  // The task queues to be used by parallel GC threads.

  ObjToScanQueueSet* task_queues() {

    return _task_queues;

  }

  PLABStats* plab_stats() {

    return &_plab_stats;

  }

  size_t desired_plab_sz();

  const ParNewTracer* gc_tracer() const {

    return &_gc_tracer;

  }

  static oop real_forwardee(oop obj);

};

#endif // SHARE_VM_GC_CMS_PARNEWGENERATION_HPP