/*
 * Copyright (c) 2016, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "gc/g1/g1YoungGenSizer.hpp"
#include "gc/g1/heapRegion.hpp"
#include "logging/log.hpp"

G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults),
  _min_desired_young_length(0), _max_desired_young_length(0), _adaptive_size(true) {

  if (FLAG_IS_CMDLINE(NewRatio)) {
    if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
      log_warning(gc, ergo)("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
    } else {
      _sizer_kind = SizerNewRatio;
      _adaptive_size = false;
      return;
    }
  }

  if (NewSize > MaxNewSize) {
    if (FLAG_IS_CMDLINE(MaxNewSize)) {
      log_warning(gc, ergo)("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
                            "A new max generation size of " SIZE_FORMAT "k will be used.",
                            NewSize/K, MaxNewSize/K, NewSize/K);
    }
    FLAG_SET_ERGO(size_t, MaxNewSize, NewSize);
  }

  if (FLAG_IS_CMDLINE(NewSize)) {
    _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
                                     1U);
    if (FLAG_IS_CMDLINE(MaxNewSize)) {
      _max_desired_young_length =
                             MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
                                  1U);
      _sizer_kind = SizerMaxAndNewSize;
      _adaptive_size = _min_desired_young_length != _max_desired_young_length;
    } else {
      _sizer_kind = SizerNewSizeOnly;
    }
  } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
    _max_desired_young_length =
                             MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
                                  1U);
    _sizer_kind = SizerMaxNewSizeOnly;
  }
}

uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
  uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
  return MAX2(1U, default_value);
}

uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
  uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
  return MAX2(1U, default_value);
}

void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
  assert(number_of_heap_regions > 0, "Heap must be initialized");

  switch (_sizer_kind) {
    case SizerDefaults:
      *min_young_length = calculate_default_min_length(number_of_heap_regions);
      *max_young_length = calculate_default_max_length(number_of_heap_regions);
      break;
    case SizerNewSizeOnly:
      *max_young_length = calculate_default_max_length(number_of_heap_regions);
      *max_young_length = MAX2(*min_young_length, *max_young_length);
      break;
    case SizerMaxNewSizeOnly:
      *min_young_length = calculate_default_min_length(number_of_heap_regions);
      *min_young_length = MIN2(*min_young_length, *max_young_length);
      break;
    case SizerMaxAndNewSize:
      // Do nothing. Values set on the command line, don't update them at runtime.
      break;
    case SizerNewRatio:
      *min_young_length = number_of_heap_regions / (NewRatio + 1);
      *max_young_length = *min_young_length;
      break;
    default:
      ShouldNotReachHere();
  }

  assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
}

void G1YoungGenSizer::adjust_max_new_size(uint number_of_heap_regions) {

  // We need to pass the desired values because recalculation may not update these
  // values in some cases.
  uint temp = _min_desired_young_length;
  uint result = _max_desired_young_length;
  recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);

  size_t max_young_size = result * HeapRegion::GrainBytes;
  if (max_young_size != MaxNewSize) {
    FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
  }
}

void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
  recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
          &_max_desired_young_length);
}