/*

 * Copyright (c) 2019, 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/collectionSetChooser.hpp"

#include "gc/g1/g1CollectionSetCandidates.hpp"

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

HeapRegion* G1CollectionSetCandidates::pop_front() {

  assert(_front_idx < _num_regions, "pre-condition");

  HeapRegion* hr = _regions[_front_idx];

  assert(hr != NULL, "pre-condition");

  _regions[_front_idx] = NULL;

  assert(hr->reclaimable_bytes() <= _remaining_reclaimable_bytes,

         "Remaining reclaimable bytes inconsistent "

         "from region: " SIZE_FORMAT " remaining: " SIZE_FORMAT,

         hr->reclaimable_bytes(), _remaining_reclaimable_bytes);

  _remaining_reclaimable_bytes -= hr->reclaimable_bytes();

  _front_idx++;

  return hr;

}

void G1CollectionSetCandidates::push_front(HeapRegion* hr) {

  assert(hr != NULL, "Can't put back a NULL region");

  assert(_front_idx >= 1, "Too many regions have been put back.");

  _front_idx--;

  _regions[_front_idx] = hr;

  _remaining_reclaimable_bytes += hr->reclaimable_bytes();

}

void G1CollectionSetCandidates::iterate(HeapRegionClosure* cl) {

  for (uint i = _front_idx; i < _num_regions; i++) {

    HeapRegion* r = _regions[i];

    if (cl->do_heap_region(r)) {

      cl->set_incomplete();

      break;

    }

  }

}

#ifndef PRODUCT

void G1CollectionSetCandidates::verify() const {

  guarantee(_front_idx <= _num_regions, "Index: %u Num_regions: %u", _front_idx, _num_regions);

  uint idx = 0;

  size_t sum_of_reclaimable_bytes = 0;

  while (idx < _front_idx) {

    guarantee(_regions[idx] == NULL, "All entries before _front_idx %u should be NULL, but %u is not",

              _front_idx, idx);

    idx++;

  }

  HeapRegion *prev = NULL;

  for (; idx < _num_regions; idx++) {

    HeapRegion *cur = _regions[idx];

    guarantee(cur != NULL, "Regions after _front_idx %u cannot be NULL but %u is", _front_idx, idx);

    guarantee(CollectionSetChooser::should_add(cur), "Region %u should be eligible for addition.", cur->hrm_index());

    if (prev != NULL) {

      guarantee(prev->gc_efficiency() >= cur->gc_efficiency(),

                "GC efficiency for region %u: %1.4f smaller than for region %u: %1.4f",

                prev->hrm_index(), prev->gc_efficiency(), cur->hrm_index(), cur->gc_efficiency());

    }

    sum_of_reclaimable_bytes += cur->reclaimable_bytes();

    prev = cur;

  }

  guarantee(sum_of_reclaimable_bytes == _remaining_reclaimable_bytes,

            "Inconsistent remaining_reclaimable bytes, remaining " SIZE_FORMAT " calculated " SIZE_FORMAT,

            _remaining_reclaimable_bytes, sum_of_reclaimable_bytes);

}

#endif // !PRODUCT