/*

 * 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.

 *

 * 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/g1CollectedHeap.hpp"

#include "gc/g1/g1CollectorPolicy.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/g1/heapRegion.inline.hpp"

#include "gc/g1/heapRegionRemSet.hpp"

#include "gc/g1/youngList.hpp"

#include "utilities/ostream.hpp"

YoungList::YoungList(G1CollectedHeap* g1h) :

    _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0),

    _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) {

  guarantee(check_list_empty(false), "just making sure...");

}

void YoungList::push_region(HeapRegion *hr) {

  assert(!hr->is_young(), "should not already be young");

  assert(hr->get_next_young_region() == NULL, "cause it should!");

  hr->set_next_young_region(_head);

  _head = hr;

  _g1h->g1_policy()->set_region_eden(hr, (int) _length);

  ++_length;

}

void YoungList::add_survivor_region(HeapRegion* hr) {

  assert(hr->is_survivor(), "should be flagged as survivor region");

  assert(hr->get_next_young_region() == NULL, "cause it should!");

  hr->set_next_young_region(_survivor_head);

  if (_survivor_head == NULL) {

    _survivor_tail = hr;

  }

  _survivor_head = hr;

  ++_survivor_length;

}

void YoungList::empty_list(HeapRegion* list) {

  while (list != NULL) {

    HeapRegion* next = list->get_next_young_region();

    list->set_next_young_region(NULL);

    list->uninstall_surv_rate_group();

    // This is called before a Full GC and all the non-empty /

    // non-humongous regions at the end of the Full GC will end up as

    // old anyway.

    list->set_old();

    list = next;

  }

}

void YoungList::empty_list() {

  assert(check_list_well_formed(), "young list should be well formed");

  empty_list(_head);

  _head = NULL;

  _length = 0;

  empty_list(_survivor_head);

  _survivor_head = NULL;

  _survivor_tail = NULL;

  _survivor_length = 0;

  _last_sampled_rs_lengths = 0;

  assert(check_list_empty(false), "just making sure...");

}

bool YoungList::check_list_well_formed() {

  bool ret = true;

  uint length = 0;

  HeapRegion* curr = _head;

  HeapRegion* last = NULL;

  while (curr != NULL) {

    if (!curr->is_young()) {

      gclog_or_tty->print_cr("### YOUNG REGION " PTR_FORMAT "-" PTR_FORMAT " "

                             "incorrectly tagged (y: %d, surv: %d)",

                             p2i(curr->bottom()), p2i(curr->end()),

                             curr->is_young(), curr->is_survivor());

      ret = false;

    }

    ++length;

    last = curr;

    curr = curr->get_next_young_region();

  }

  ret = ret && (length == _length);

  if (!ret) {

    gclog_or_tty->print_cr("### YOUNG LIST seems not well formed!");

    gclog_or_tty->print_cr("###   list has %u entries, _length is %u",

                           length, _length);

  }

  return ret;

}

bool YoungList::check_list_empty(bool check_sample) {

  bool ret = true;

  if (_length != 0) {

    gclog_or_tty->print_cr("### YOUNG LIST should have 0 length, not %u",

                  _length);

    ret = false;

  }

  if (check_sample && _last_sampled_rs_lengths != 0) {

    gclog_or_tty->print_cr("### YOUNG LIST has non-zero last sampled RS lengths");

    ret = false;

  }

  if (_head != NULL) {

    gclog_or_tty->print_cr("### YOUNG LIST does not have a NULL head");

    ret = false;

  }

  if (!ret) {

    gclog_or_tty->print_cr("### YOUNG LIST does not seem empty");

  }

  return ret;

}

void

YoungList::rs_length_sampling_init() {

  _sampled_rs_lengths = 0;

  _curr               = _head;

}

bool

YoungList::rs_length_sampling_more() {

  return _curr != NULL;

}

void

YoungList::rs_length_sampling_next() {

  assert( _curr != NULL, "invariant" );

  size_t rs_length = _curr->rem_set()->occupied();

  _sampled_rs_lengths += rs_length;

  // The current region may not yet have been added to the

  // incremental collection set (it gets added when it is

  // retired as the current allocation region).

  if (_curr->in_collection_set()) {

    // Update the collection set policy information for this region

    _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length);

  }

  _curr = _curr->get_next_young_region();

  if (_curr == NULL) {

    _last_sampled_rs_lengths = _sampled_rs_lengths;

    // gclog_or_tty->print_cr("last sampled RS lengths = %d", _last_sampled_rs_lengths);

  }

}

void

YoungList::reset_auxilary_lists() {

  guarantee( is_empty(), "young list should be empty" );

  assert(check_list_well_formed(), "young list should be well formed");

  // Add survivor regions to SurvRateGroup.

  _g1h->g1_policy()->note_start_adding_survivor_regions();

  _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);

  int young_index_in_cset = 0;

  for (HeapRegion* curr = _survivor_head;

       curr != NULL;

       curr = curr->get_next_young_region()) {

    _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset);

    // The region is a non-empty survivor so let's add it to

    // the incremental collection set for the next evacuation

    // pause.

    _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr);

    young_index_in_cset += 1;

  }

  assert((uint) young_index_in_cset == _survivor_length, "post-condition");

  _g1h->g1_policy()->note_stop_adding_survivor_regions();

  _head   = _survivor_head;

  _length = _survivor_length;

  if (_survivor_head != NULL) {

    assert(_survivor_tail != NULL, "cause it shouldn't be");

    assert(_survivor_length > 0, "invariant");

    _survivor_tail->set_next_young_region(NULL);

  }

  // Don't clear the survivor list handles until the start of

  // the next evacuation pause - we need it in order to re-tag

  // the survivor regions from this evacuation pause as 'young'

  // at the start of the next.

  _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);

  assert(check_list_well_formed(), "young list should be well formed");

}

void YoungList::print() {

  HeapRegion* lists[] = {_head,   _survivor_head};

  const char* names[] = {"YOUNG", "SURVIVOR"};

  for (uint list = 0; list < ARRAY_SIZE(lists); ++list) {

    gclog_or_tty->print_cr("%s LIST CONTENTS", names[list]);

    HeapRegion *curr = lists[list];

    if (curr == NULL) {

      gclog_or_tty->print_cr("  empty");

    }

    while (curr != NULL) {

      gclog_or_tty->print_cr("  " HR_FORMAT ", P: " PTR_FORMAT ", N: " PTR_FORMAT ", age: %4d",

                             HR_FORMAT_PARAMS(curr),

                             p2i(curr->prev_top_at_mark_start()),

                             p2i(curr->next_top_at_mark_start()),

                             curr->age_in_surv_rate_group_cond());

      curr = curr->get_next_young_region();

    }

  }

  gclog_or_tty->cr();

}