/*
 * Copyright (c) 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "gc/g1/g1CollectedHeap.hpp"
#include "gc/g1/g1FullCollector.hpp"
#include "gc/g1/g1FullGCMarker.hpp"
#include "gc/g1/g1FullGCOopClosures.inline.hpp"
#include "gc/g1/g1FullGCReferenceProcessorExecutor.hpp"
#include "gc/shared/gcTraceTime.inline.hpp"
#include "gc/shared/referenceProcessor.hpp"

G1FullGCReferenceProcessingExecutor::G1FullGCReferenceProcessingExecutor(G1FullCollector* collector) :
    _collector(collector),
    _reference_processor(collector->reference_processor()),
    _old_mt_degree(_reference_processor->num_queues()) {
  if (_reference_processor->processing_is_mt()) {
    _reference_processor->set_active_mt_degree(_collector->workers());
  }
}

G1FullGCReferenceProcessingExecutor::~G1FullGCReferenceProcessingExecutor() {
  if (_reference_processor->processing_is_mt()) {
    _reference_processor->set_active_mt_degree(_old_mt_degree);
  }
}

G1FullGCReferenceProcessingExecutor::G1RefProcTaskProxy::G1RefProcTaskProxy(ProcessTask& proc_task,
                                                                      G1FullCollector* collector) :
     AbstractGangTask("G1 reference processing task"),
     _proc_task(proc_task),
     _collector(collector),
     _terminator(_collector->workers(), _collector->oop_queue_set()) { }

void G1FullGCReferenceProcessingExecutor::G1RefProcTaskProxy::work(uint worker_id) {
  G1FullGCMarker* marker = _collector->marker(worker_id);
  G1IsAliveClosure is_alive(_collector->mark_bitmap());
  G1FullKeepAliveClosure keep_alive(marker);
  _proc_task.work(worker_id,
                  is_alive,
                  keep_alive,
                  *marker->stack_closure());
}

G1FullGCReferenceProcessingExecutor::G1RefEnqueueTaskProxy::G1RefEnqueueTaskProxy(EnqueueTask& enq_task) :
  AbstractGangTask("G1 reference enqueue task"),
  _enq_task(enq_task) { }

void G1FullGCReferenceProcessingExecutor::G1RefEnqueueTaskProxy::work(uint worker_id) {
  _enq_task.work(worker_id);
}

void G1FullGCReferenceProcessingExecutor::run_task(AbstractGangTask* task) {
  G1CollectedHeap::heap()->workers()->run_task(task, _collector->workers());
}

void G1FullGCReferenceProcessingExecutor::execute(ProcessTask& proc_task) {
  G1RefProcTaskProxy proc_task_proxy(proc_task, _collector);
  run_task(&proc_task_proxy);
}

// Driver routine for parallel reference processing.
void G1FullGCReferenceProcessingExecutor::execute(EnqueueTask& enq_task) {
  G1RefEnqueueTaskProxy enq_task_proxy(enq_task);
  run_task(&enq_task_proxy);
}

void G1FullGCReferenceProcessingExecutor::execute(STWGCTimer* timer, G1FullGCTracer* tracer) {
  GCTraceTime(Debug, gc, phases) debug("Phase 1: Reference Processing", timer);
  // Process reference objects found during marking.
  G1FullGCMarker* marker = _collector->marker(0);
  G1IsAliveClosure is_alive(_collector->mark_bitmap());
  G1FullKeepAliveClosure keep_alive(marker);
  ReferenceProcessorPhaseTimes pt(timer, _reference_processor->num_queues());
  AbstractRefProcTaskExecutor* executor = _reference_processor->processing_is_mt() ? this : NULL;

  // Process discovered references, use this executor if multi-threaded
  // processing is enabled.
  const ReferenceProcessorStats& stats =
      _reference_processor->process_discovered_references(&is_alive,
                                                          &keep_alive,
                                                          marker->stack_closure(),
                                                          executor,
                                                          &pt);

  tracer->report_gc_reference_stats(stats);
  pt.print_all_references();

  assert(marker->oop_stack()->is_empty(), "Should be no oops on the stack");

  // Now enqueue the references.
  _reference_processor->enqueue_discovered_references(executor, &pt);
  pt.print_enqueue_phase();
}