/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * 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"
#include "utilities/numberSeq.hpp"

class G1Predictions;

// Manages the decision about the threshold when concurrent marking should start.
class G1IHOPControl : public CHeapObj<mtGC> {
 protected:
  double _ihop_percent;
  size_t _target_occupancy;

  // 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);
 public:
  virtual ~G1IHOPControl() { }

  // Get the current marking threshold in bytes.
  virtual size_t get_conc_mark_start_threshold() = 0;

  // Update information about recent time during which allocations happened,
  // how many allocations happened and an additional safety buffer.
  virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) = 0;
  // Update the time from the end of initial mark to the first mixed gc.
  virtual void update_time_to_mixed(double marking_length_s) = 0;

  virtual void print() = 0;
};

class G1StaticIHOPControl : public G1IHOPControl {
  double _last_allocation_time_s;
  size_t _last_allocated_bytes;
  double _last_marking_length_s;
 public:
  G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);

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

  virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
    assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
    _last_allocation_time_s = allocation_time_s;
    _last_allocated_bytes = allocated_bytes;
  }

  virtual void update_time_to_mixed(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;
  }

  virtual void print();
#ifndef PRODUCT
  static void test();
#endif
};

class G1AdaptiveIHOPControl : public G1IHOPControl {
  G1Predictions const * _predictor;

  TruncatedSeq _marking_times_s;
  TruncatedSeq _allocation_rate_s;

  size_t _last_allocation_bytes; // Most recent mutator allocation since last GC.
  size_t _prev_unrestrained_young_size;

  size_t _current_threshold;

  // Updates _current_threshold according to internal state.
  void recalculate();

  bool have_enough_data_for_prediction() const;
 public:
  G1AdaptiveIHOPControl(double ihop_percent, size_t initial_target_occupancy, G1Predictions const* predictor);

  virtual void set_target_occupancy(size_t target_occupancy);

  virtual size_t get_conc_mark_start_threshold();

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

  virtual void print();
#ifndef PRODUCT
  static void test();
#endif
};

#endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP