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.marksweep;
014
015import org.mmtk.plan.*;
016import org.mmtk.vm.VM;
017
018import org.vmmagic.pragma.*;
019
020/**
021 * This class implements <i>per-collector thread</i> behavior
022 * and state for the <i>MS</i> plan, which implements a full-heap
023 * mark-sweep collector.<p>
024 *
025 * Specifically, this class defines <i>MS</i> collection behavior
026 * (through <code>trace</code> and the <code>collectionPhase</code>
027 * method).<p>
028 *
029 * @see MS for an overview of the mark-sweep algorithm.
030 *
031 * @see MS
032 * @see MSMutator
033 * @see StopTheWorldCollector
034 * @see CollectorContext
035 */
036@Uninterruptible
037public class MSCollector extends StopTheWorldCollector {
038
039  /****************************************************************************
040   * Instance fields
041   */
042
043  /**
044   *
045   */
046  protected MSTraceLocal fullTrace = new MSTraceLocal(global().msTrace, null);;
047  protected TraceLocal currentTrace = fullTrace;
048
049
050  /****************************************************************************
051   * Collection
052   */
053
054  /**
055   * {@inheritDoc}
056   */
057  @Inline
058  @Override
059  public void collectionPhase(short phaseId, boolean primary) {
060    if (phaseId == MS.PREPARE) {
061      super.collectionPhase(phaseId, primary);
062      fullTrace.prepare();
063      return;
064    }
065
066    if (phaseId == MS.CLOSURE) {
067      fullTrace.completeTrace();
068      return;
069    }
070
071    if (phaseId == MS.RELEASE) {
072      fullTrace.release();
073      super.collectionPhase(phaseId, primary);
074      return;
075    }
076
077    super.collectionPhase(phaseId, primary);
078  }
079
080
081  /****************************************************************************
082   * Miscellaneous
083   */
084
085  /** @return The active global plan as an <code>MS</code> instance. */
086  @Inline
087  private static MS global() {
088    return (MS) VM.activePlan.global();
089  }
090
091  @Override
092  public final TraceLocal getCurrentTrace() {
093    return currentTrace;
094  }
095}