001/*
002 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 *  This file is licensed to You under the Eclipse Public License (EPL);
005 *  You may not use this file except in compliance with the License. You
006 *  may obtain a copy of the License at
007 *
008 *      http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 *  See the COPYRIGHT.txt file distributed with this work for information
011 *  regarding copyright ownership.
012 */
013package org.mmtk.plan;
014
015import org.mmtk.utility.statistics.Timer;
016import org.mmtk.utility.Log;
017import org.mmtk.vm.VM;
018
019import org.vmmagic.pragma.*;
020
021/**
022 * Phases of a garbage collection.<p>
023 *
024 * A concurrent phase runs concurrently with mutator activity.
025 */
026@Uninterruptible
027public final class ConcurrentPhase extends Phase {
028
029  /****************************************************************************
030   * Instance fields
031   */
032
033  /**
034   * The atomic scheduled phase to use when concurrent collection is not allowed
035   */
036  private final int atomicScheduledPhase;
037
038  /**
039   * Construct a complex phase from an array of phase IDs.
040   *
041   * @param name The name of the phase.
042   * @param atomicScheduledPhase The atomic scheduled phase
043   */
044  protected ConcurrentPhase(String name, int atomicScheduledPhase) {
045    super(name, null);
046    this.atomicScheduledPhase = atomicScheduledPhase;
047    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(getSchedule(this.atomicScheduledPhase) != SCHEDULE_CONCURRENT);
048  }
049
050  /**
051   * Construct a complex phase from an array of phase IDs, but using
052   * the specified timer rather than creating one.
053   *
054   * @param name The name of the phase.
055   * @param timer The timer for this phase to contribute to.
056   * @param atomicScheduledPhase The atomic scheduled phase
057   */
058  protected ConcurrentPhase(String name, Timer timer, int atomicScheduledPhase) {
059    super(name, timer);
060    if (VM.VERIFY_ASSERTIONS) {
061      /* Timers currently unsupported on concurrent phases */
062      VM.assertions._assert(timer == null);
063    }
064    this.atomicScheduledPhase = atomicScheduledPhase;
065    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(getSchedule(this.atomicScheduledPhase) != SCHEDULE_CONCURRENT);
066  }
067
068  @Override
069  protected void logPhase() {
070    Log.write("ConcurrentPhase(");
071    Log.write(name);
072    Log.write(")");
073  }
074
075  /**
076   * Return the atomic schedule phase, to be used in place of this phase when
077   * concurrent collection is not available.
078   *
079   * @return The atomic scheduled phase.
080   */
081  protected int getAtomicScheduledPhase() {
082    return this.atomicScheduledPhase;
083  }
084}