/*

 * Copyright (c) 2001, 2017, 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

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 */

#include "precompiled.hpp"

#include "gc/g1/concurrentG1Refine.hpp"

#include "gc/g1/concurrentG1RefineThread.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1RemSet.hpp"

#include "gc/shared/suspendibleThreadSet.hpp"

#include "logging/log.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/mutexLocker.hpp"

ConcurrentG1RefineThread::

ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next,

                         uint worker_id_offset, uint worker_id,

                         size_t activate, size_t deactivate) :

  ConcurrentGCThread(),

  _worker_id_offset(worker_id_offset),

  _worker_id(worker_id),

  _active(false),

  _next(next),

  _monitor(NULL),

  _cg1r(cg1r),

  _vtime_accum(0.0),

  _activation_threshold(activate),

  _deactivation_threshold(deactivate)

{

  // 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 ConcurrentG1RefineThread::update_thresholds(size_t activate,

                                                 size_t deactivate) {

  assert(deactivate < activate, "precondition");

  _activation_threshold = activate;

  _deactivation_threshold = deactivate;

}

void ConcurrentG1RefineThread::wait_for_completed_buffers() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

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

    _monitor->wait(Mutex::_no_safepoint_check_flag);

  }

}

bool ConcurrentG1RefineThread::is_active() {

  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

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

}

void ConcurrentG1RefineThread::activate() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  if (!is_primary()) {

    set_active(true);

  } else {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    dcqs.set_process_completed(true);

  }

  _monitor->notify();

}

void ConcurrentG1RefineThread::deactivate() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  if (!is_primary()) {

    set_active(false);

  } else {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    dcqs.set_process_completed(false);

  }

}

void ConcurrentG1RefineThread::run_service() {

  _vtime_start = os::elapsedVTime();

  while (!should_terminate()) {

    // Wait for work

    wait_for_completed_buffers();

    if (should_terminate()) {

      break;

    }

    size_t buffers_processed = 0;

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

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

                          _worker_id, _activation_threshold, dcqs.completed_buffers_num());

    {

      SuspendibleThreadSetJoiner sts_join;

      while (!should_terminate()) {

        if (sts_join.should_yield()) {

          sts_join.yield();

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

        }

        size_t curr_buffer_num = dcqs.completed_buffers_num();

        // If the number of the buffers falls down into the yellow zone,

        // that means that the transition period after the evacuation pause has ended.

        if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {

          dcqs.set_completed_queue_padding(0);

        }

        // Check if we need to activate the next thread.

        if ((_next != NULL) &&

            !_next->is_active() &&

            (curr_buffer_num > _next->_activation_threshold)) {

          _next->activate();

        }

        // Process the next buffer, if there are enough left.

        if (!dcqs.refine_completed_buffer_concurrently(_worker_id + _worker_id_offset, _deactivation_threshold)) {

          break; // Deactivate, number of buffers fell below threshold.

        }

        ++buffers_processed;

      }

    }

    deactivate();

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

                          ", current: " SIZE_FORMAT ", processed: " SIZE_FORMAT,

                          _worker_id, _deactivation_threshold,

                          dcqs.completed_buffers_num(),

                          buffers_processed);

    if (os::supports_vtime()) {

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

    } else {

      _vtime_accum = 0.0;

    }

  }

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

}

void ConcurrentG1RefineThread::stop_service() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  _monitor->notify();

}