/*

 * Copyright (c) 2001, 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/g1BarrierSet.hpp"

#include "gc/g1/g1ConcurrentRefine.hpp"

#include "gc/g1/g1ConcurrentRefineThread.hpp"

#include "gc/g1/g1DirtyCardQueue.hpp"

#include "gc/shared/suspendibleThreadSet.hpp"

#include "logging/log.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/mutexLocker.hpp"

G1ConcurrentRefineThread::G1ConcurrentRefineThread(G1ConcurrentRefine* cr, uint worker_id) :

  ConcurrentGCThread(),

  _vtime_start(0.0),

  _vtime_accum(0.0),

  _total_refinement_time(),

  _total_refined_cards(0),

  _worker_id(worker_id),

  _active(false),

  _monitor(NULL),

  _cr(cr)

{

  // Each thread has its own monitor. The i-th thread is responsible for signaling

  // to thread i+1 if the number of buffers in the queue exceeds a threshold for this

  // thread. Monitors are also used to wake up the threads during termination.

  // The 0th (primary) worker is notified by mutator threads and has a special monitor.

  if (!is_primary()) {

    _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true,

                           Monitor::_safepoint_check_never);

  } else {

    _monitor = DirtyCardQ_CBL_mon;

  }

  // set name

  set_name("G1 Refine#%d", worker_id);

  create_and_start();

}

void G1ConcurrentRefineThread::wait_for_completed_buffers() {

  MonitorLocker ml(_monitor, Mutex::_no_safepoint_check_flag);

  while (!should_terminate() && !is_active()) {

    ml.wait();

  }

}

bool G1ConcurrentRefineThread::is_active() {

  G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();

  return is_primary() ? dcqs.process_completed_buffers() : _active;

}

void G1ConcurrentRefineThread::activate() {

  MutexLocker x(_monitor, Mutex::_no_safepoint_check_flag);

  if (!is_primary()) {

    set_active(true);

  } else {

    G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();

    dcqs.set_process_completed_buffers(true);

  }

  _monitor->notify();

}

void G1ConcurrentRefineThread::deactivate() {

  MutexLocker x(_monitor, Mutex::_no_safepoint_check_flag);

  if (!is_primary()) {

    set_active(false);

  } else {

    G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();

    dcqs.set_process_completed_buffers(false);

  }

}

void G1ConcurrentRefineThread::run_service() {

  _vtime_start = os::elapsedVTime();

  while (!should_terminate()) {

    // Wait for work

    wait_for_completed_buffers();

    if (should_terminate()) {

      break;

    }

    log_debug(gc, refine)("Activated worker %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,

                          _worker_id, _cr->activation_threshold(_worker_id),

                          G1BarrierSet::dirty_card_queue_set().num_cards());

    size_t start_total_refined_cards = _total_refined_cards; // For logging.

    {

      SuspendibleThreadSetJoiner sts_join;

      while (!should_terminate()) {

        if (sts_join.should_yield()) {

          sts_join.yield();

          continue;             // Re-check for termination after yield delay.

        }

        Ticks start_time = Ticks::now();

        if (!_cr->do_refinement_step(_worker_id, &_total_refined_cards)) {

          break;                // No cards to process.

        }

        _total_refinement_time += (Ticks::now() - start_time);

      }

    }

    deactivate();

    log_debug(gc, refine)("Deactivated worker %d, off threshold: " SIZE_FORMAT

                          ", current: " SIZE_FORMAT ", refined cards: "

                          SIZE_FORMAT ", total refined cards: " SIZE_FORMAT,

                          _worker_id, _cr->deactivation_threshold(_worker_id),

                          G1BarrierSet::dirty_card_queue_set().num_cards(),

                          _total_refined_cards - start_total_refined_cards,

                          _total_refined_cards);

    if (os::supports_vtime()) {

      _vtime_accum = (os::elapsedVTime() - _vtime_start);

    } else {

      _vtime_accum = 0.0;

    }

  }

  log_debug(gc, refine)("Stopping %d", _worker_id);

}

void G1ConcurrentRefineThread::stop_service() {

  MutexLocker x(_monitor, Mutex::_no_safepoint_check_flag);

  _monitor->notify();

}