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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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#ifndef SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP

#define SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP

#include "gc/shared/barrierSet.hpp"

#include "gc/shared/cardTableRS.hpp"

#include "gc/shared/generationSpec.hpp"

#include "memory/allocation.hpp"

#include "utilities/macros.hpp"

// This class (or more correctly, subtypes of this class)

// are used to define global garbage collector attributes.

// This includes initialization of generations and any other

// shared resources they may need.

//

// In general, all flag adjustment and validation should be

// done in initialize_flags(), which is called prior to

// initialize_size_info().

//

// This class is not fully developed yet. As more collector(s)

// are added, it is expected that we will come across further

// behavior that requires global attention. The correct place

// to deal with those issues is this class.

// Forward declarations.

class GenCollectorPolicy;

class AdaptiveSizePolicy;

#if INCLUDE_ALL_GCS

class ConcurrentMarkSweepPolicy;

class G1CollectorPolicy;

#endif // INCLUDE_ALL_GCS

class GCPolicyCounters;

class MarkSweepPolicy;

class CollectorPolicy : public CHeapObj<mtGC> {

 protected:

  virtual void initialize_alignments() = 0;

  virtual void initialize_flags();

  virtual void initialize_size_info();

  DEBUG_ONLY(virtual void assert_flags();)

  DEBUG_ONLY(virtual void assert_size_info();)

  size_t _initial_heap_byte_size;

  size_t _max_heap_byte_size;

  size_t _min_heap_byte_size;

  size_t _space_alignment;

  size_t _heap_alignment;

  // Set to true when policy wants soft refs cleared.

  // Reset to false by gc after it clears all soft refs.

  bool _should_clear_all_soft_refs;

  // Set to true by the GC if the just-completed gc cleared all

  // softrefs.  This is set to true whenever a gc clears all softrefs, and

  // set to false each time gc returns to the mutator.  For example, in the

  // ParallelScavengeHeap case the latter would be done toward the end of

  // mem_allocate() where it returns op.result()

  bool _all_soft_refs_clear;

  CollectorPolicy();

 public:

  virtual void initialize_all() {

    initialize_alignments();

    initialize_flags();

    initialize_size_info();

  }

  // Return maximum heap alignment that may be imposed by the policy.

  static size_t compute_heap_alignment();

  size_t space_alignment()        { return _space_alignment; }

  size_t heap_alignment()         { return _heap_alignment; }

  size_t initial_heap_byte_size() { return _initial_heap_byte_size; }

  size_t max_heap_byte_size()     { return _max_heap_byte_size; }

  size_t min_heap_byte_size()     { return _min_heap_byte_size; }

  bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }

  void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }

  // Returns the current value of _should_clear_all_soft_refs.

  // _should_clear_all_soft_refs is set to false as a side effect.

  bool use_should_clear_all_soft_refs(bool v);

  bool all_soft_refs_clear() { return _all_soft_refs_clear; }

  void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }

  // Called by the GC after Soft Refs have been cleared to indicate

  // that the request in _should_clear_all_soft_refs has been fulfilled.

  virtual void cleared_all_soft_refs();

};

class ClearedAllSoftRefs : public StackObj {

  bool _clear_all_soft_refs;

  CollectorPolicy* _collector_policy;

 public:

  ClearedAllSoftRefs(bool clear_all_soft_refs,

                     CollectorPolicy* collector_policy) :

    _clear_all_soft_refs(clear_all_soft_refs),

    _collector_policy(collector_policy) {}

  ~ClearedAllSoftRefs() {

    if (_clear_all_soft_refs) {

      _collector_policy->cleared_all_soft_refs();

    }

  }

  bool should_clear() { return _clear_all_soft_refs; }

};

class GenCollectorPolicy : public CollectorPolicy {

  friend class TestGenCollectorPolicy;

  friend class VMStructs;

protected:

  size_t _min_young_size;

  size_t _initial_young_size;

  size_t _max_young_size;

  size_t _min_old_size;

  size_t _initial_old_size;

  size_t _max_old_size;

  // _gen_alignment and _space_alignment will have the same value most of the

  // time. When using large pages they can differ.

  size_t _gen_alignment;

  GenerationSpec* _young_gen_spec;

  GenerationSpec* _old_gen_spec;

  GCPolicyCounters* _gc_policy_counters;

  // The sizing of the heap is controlled by a sizing policy.

  AdaptiveSizePolicy* _size_policy;

  // Return true if an allocation should be attempted in the older generation

  // if it fails in the younger generation.  Return false, otherwise.

  virtual bool should_try_older_generation_allocation(size_t word_size) const;

  void initialize_flags();

  void initialize_size_info();

  DEBUG_ONLY(void assert_flags();)

  DEBUG_ONLY(void assert_size_info();)

  // Try to allocate space by expanding the heap.

  virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);

  // Compute max heap alignment.

  size_t compute_max_alignment();

  // Scale the base_size by NewRatio according to

  //     result = base_size / (NewRatio + 1)

  // and align by min_alignment()

  size_t scale_by_NewRatio_aligned(size_t base_size);

  // Bound the value by the given maximum minus the min_alignment.

  size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);

 public:

  GenCollectorPolicy();

  // Accessors

  size_t min_young_size()     { return _min_young_size; }

  size_t initial_young_size() { return _initial_young_size; }

  size_t max_young_size()     { return _max_young_size; }

  size_t gen_alignment()      { return _gen_alignment; }

  size_t min_old_size()       { return _min_old_size; }

  size_t initial_old_size()   { return _initial_old_size; }

  size_t max_old_size()       { return _max_old_size; }

  GenerationSpec* young_gen_spec() const {

    assert(_young_gen_spec != NULL, "_young_gen_spec should have been initialized");

    return _young_gen_spec;

  }

  GenerationSpec* old_gen_spec() const {

    assert(_old_gen_spec != NULL, "_old_gen_spec should have been initialized");

    return _old_gen_spec;

  }

  // Performance Counter support

  GCPolicyCounters* counters()     { return _gc_policy_counters; }

  // Create the jstat counters for the GC policy.

  virtual void initialize_gc_policy_counters() = 0;

  virtual void initialize_generations() { };

  virtual void initialize_all() {

    CollectorPolicy::initialize_all();

    initialize_generations();

  }

  size_t young_gen_size_lower_bound();

  size_t old_gen_size_lower_bound();

  HeapWord* mem_allocate_work(size_t size,

                              bool is_tlab,

                              bool* gc_overhead_limit_was_exceeded);

  HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab);

  // Adaptive size policy

  AdaptiveSizePolicy* size_policy() { return _size_policy; }

  virtual void initialize_size_policy(size_t init_eden_size,

                                      size_t init_promo_size,

                                      size_t init_survivor_size);

  virtual void cleared_all_soft_refs();

};

class MarkSweepPolicy : public GenCollectorPolicy {

 protected:

  void initialize_alignments();

  void initialize_generations();

 public:

  MarkSweepPolicy() {}

  void initialize_gc_policy_counters();

};

#endif // SHARE_VM_GC_SHARED_COLLECTORPOLICY_HPP