/*

 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.

 *

 * 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/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"

#include "gc/shenandoah/shenandoahCollectionSet.hpp"

#include "gc/shenandoah/shenandoahHeapRegion.hpp"

#include "logging/log.hpp"

#include "logging/logTag.hpp"

#include "runtime/os.hpp"

ShenandoahAggressiveHeuristics::ShenandoahAggressiveHeuristics() : ShenandoahHeuristics() {

  // Do not shortcut evacuation

  SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100);

  // Aggressive runs with max speed for allocation, to capture races against mutator

  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahPacing);

  // Aggressive evacuates everything, so it needs as much evac space as it can get

  SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahEvacReserveOverflow);

  // If class unloading is globally enabled, aggressive does unloading even with

  // concurrent cycles.

  if (ClassUnloading) {

    SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUnloadClassesFrequency, 1);

  }

  // Final configuration checks

  SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier);

  SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);

  SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier);

  SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);

  SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);

}

void ShenandoahAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset,

                                                                           RegionData* data, size_t size,

                                                                           size_t free) {

  for (size_t idx = 0; idx < size; idx++) {

    ShenandoahHeapRegion* r = data[idx]._region;

    if (r->garbage() > 0) {

      cset->add_region(r);

    }

  }

}

bool ShenandoahAggressiveHeuristics::should_start_gc() const {

  log_info(gc)("Trigger: Start next cycle immediately");

  return true;

}

bool ShenandoahAggressiveHeuristics::should_process_references() {

  if (!can_process_references()) return false;

  // Randomly process refs with 50% chance.

  return (os::random() & 1) == 1;

}

bool ShenandoahAggressiveHeuristics::should_unload_classes() {

  if (!can_unload_classes_normal()) return false;

  if (has_metaspace_oom()) return true;

  // Randomly unload classes with 50% chance.

  return (os::random() & 1) == 1;

}

const char* ShenandoahAggressiveHeuristics::name() {

  return "aggressive";

}

bool ShenandoahAggressiveHeuristics::is_diagnostic() {

  return true;

}

bool ShenandoahAggressiveHeuristics::is_experimental() {

  return false;

}