/*
 * Copyright (c) 2018, 2019, 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/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahSATBMarkQueueSet.hpp"
#include "gc/shenandoah/shenandoahThreadLocalData.hpp"

ShenandoahSATBMarkQueueSet::ShenandoahSATBMarkQueueSet(BufferNode::Allocator* allocator) :
  SATBMarkQueueSet(allocator)
{}

SATBMarkQueue& ShenandoahSATBMarkQueueSet::satb_queue_for_thread(Thread* const t) const {
  return ShenandoahThreadLocalData::satb_mark_queue(t);
}

template <bool RESOLVE>
class ShenandoahSATBMarkQueueFilterFn {
  ShenandoahHeap* const _heap;

public:
  ShenandoahSATBMarkQueueFilterFn(ShenandoahHeap* heap) : _heap(heap) {}

  // Return true if entry should be filtered out (removed), false if
  // it should be retained.
  bool operator()(const void* entry) const {
    return !_heap->requires_marking<RESOLVE>(entry);
  }
};

void ShenandoahSATBMarkQueueSet::filter(SATBMarkQueue* queue) {
  ShenandoahHeap* heap = ShenandoahHeap::heap();
  if (heap->has_forwarded_objects()) {
    apply_filter(ShenandoahSATBMarkQueueFilterFn<true>(heap), queue);
  } else {
    apply_filter(ShenandoahSATBMarkQueueFilterFn<false>(heap), queue);
  }
}

void ShenandoahSATBMarkQueue::handle_completed_buffer() {
  SATBMarkQueue::handle_completed_buffer();
  if (!is_empty()) {
    Thread* t = Thread::current();
    if (ShenandoahThreadLocalData::is_force_satb_flush(t)) {
      // Non-empty buffer is compacted, and we decided not to enqueue it.
      // We still want to know about leftover work in that buffer eventually.
      // This avoid dealing with these leftovers during the final-mark, after
      // the buffers are drained completely. See JDK-8205353 for more discussion.
      ShenandoahThreadLocalData::set_force_satb_flush(t, false);
      enqueue_completed_buffer();
    }
  }
}