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.vm.VM;
016import org.vmmagic.pragma.*;
017
018/**
019 * This class (and its sub-classes) implement <i>per-collector thread</i>
020 * behavior and state.<p>
021 *
022 * MMTk assumes that the VM instantiates instances of CollectorContext
023 * in thread local storage (TLS) for each thread participating in
024 * collection.  Accesses to this state are therefore assumed to be
025 * low-cost during mutator time.
026 *
027 * @see CollectorContext
028 */
029@Uninterruptible
030public abstract class StopTheWorldCollector extends SimpleCollector {
031
032  /****************************************************************************
033   *
034   * Collection.
035   */
036
037  /** Perform garbage collection */
038  @Override
039  public void collect() {
040    Phase.beginNewPhaseStack(Phase.scheduleComplex(global().collection));
041  }
042
043  /** Perform some concurrent garbage collection */
044  @Unpreemptible
045  public final void concurrentCollect() {
046    VM.assertions.fail("concurrentCollect called on StopTheWorld collector");
047  }
048
049  /**
050   * Perform some concurrent collection work.
051   *
052   * @param phaseId The unique phase identifier
053   */
054  public void concurrentCollectionPhase(short phaseId) {
055    VM.assertions.fail("concurrentCollectionPhase triggered on StopTheWorld collector");
056  }
057
058  /****************************************************************************
059   *
060   * Miscellaneous.
061   */
062
063  /** @return The active global plan as a <code>StopTheWorld</code> instance. */
064  @Inline
065  private static StopTheWorld global() {
066    return (StopTheWorld) VM.activePlan.global();
067  }
068}