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 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * 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_G1_G1IHOPCONTROL_HPP

#define SHARE_VM_GC_G1_G1IHOPCONTROL_HPP

#include "memory/allocation.hpp"

// Base class for algorithms that calculate the heap occupancy at which

// concurrent marking should start. This heap usage threshold should be relative

// to old gen size.

class G1IHOPControl : public CHeapObj<mtGC> {

 protected:

  // The initial IHOP value relative to the target occupancy.

  double _initial_ihop_percent;

  // The target maximum occupancy of the heap.

  size_t _target_occupancy;

  // Most recent complete mutator allocation period in seconds.

  double _last_allocation_time_s;

  // Amount of bytes allocated during _last_allocation_time_s.

  size_t _last_allocated_bytes;

  // Initialize an instance with the initial IHOP value in percent and the target

  // occupancy. The target occupancy is the number of bytes when marking should

  // be finished and reclaim started.

  G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);

  // Most recent time from the end of the initial mark to the start of the first

  // mixed gc.

  virtual double last_marking_length_s() const = 0;

 public:

  virtual ~G1IHOPControl() { }

  // Get the current non-young occupancy at which concurrent marking should start.

  virtual size_t get_conc_mark_start_threshold() = 0;

  // Update information about time during which allocations in the Java heap occurred,

  // how large these allocations were in bytes, and an additional buffer.

  // The allocations should contain any amount of space made unusable for further

  // allocation, e.g. any waste caused by TLAB allocation, space at the end of

  // humongous objects that can not be used for allocation, etc.

  // Together with the target occupancy, this additional buffer should contain the

  // difference between old gen size and total heap size at the start of reclamation,

  // and space required for that reclamation.

  virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size);

  // Update the time spent in the mutator beginning from the end of initial mark to

  // the first mixed gc.

  virtual void update_marking_length(double marking_length_s) = 0;

  virtual void print();

};

// The returned concurrent mark starting occupancy threshold is a fixed value

// relative to the maximum heap size.

class G1StaticIHOPControl : public G1IHOPControl {

  // Most recent mutator time between the end of initial mark to the start of the

  // first mixed gc.

  double _last_marking_length_s;

 protected:

  double last_marking_length_s() const { return _last_marking_length_s; }

 public:

  G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);

  size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }

  virtual void update_marking_length(double marking_length_s) {

   assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);

    _last_marking_length_s = marking_length_s;

  }

#ifndef PRODUCT

  static void test();

#endif

};

#endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP