/* * This file is part of the Jikes RVM project (http://jikesrvm.org). * * This file is licensed to You under the Eclipse Public License (EPL); * You may not use this file except in compliance with the License. You * may obtain a copy of the License at * * http://www.opensource.org/licenses/eclipse-1.0.php * * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. */ package org.mmtk.plan.marksweep; import org.mmtk.plan.*; import org.mmtk.policy.MarkSweepSpace; import org.mmtk.policy.Space; import org.mmtk.utility.heap.VMRequest; import org.vmmagic.pragma.*; import org.vmmagic.unboxed.*; /** * This class implements the global state of a simple mark-sweep collector.<p> * * All plans make a clear distinction between <i>global</i> and * <i>thread-local</i> activities, and divides global and local state * into separate class hierarchies. Global activities must be * synchronized, whereas no synchronization is required for * thread-local activities. There is a single instance of Plan (or the * appropriate sub-class), and a 1:1 mapping of PlanLocal to "kernel * threads" (aka CPUs). Thus instance * methods of PlanLocal allow fast, unsychronized access to functions such as * allocation and collection.<p> * * The global instance defines and manages static resources * (such as memory and virtual memory resources). This mapping of threads to * instances is crucial to understanding the correctness and * performance properties of MMTk plans. */ @Uninterruptible public class MS extends StopTheWorld { /**************************************************************************** * Class variables */ /** * */ public static final MarkSweepSpace msSpace = new MarkSweepSpace("ms", VMRequest.discontiguous()); public static final int MARK_SWEEP = msSpace.getDescriptor(); public static final int SCAN_MARK = 0; /**************************************************************************** * Instance variables */ /** * */ public final Trace msTrace = new Trace(metaDataSpace); /***************************************************************************** * Collection */ /** * {@inheritDoc} */ @Inline @Override public void collectionPhase(short phaseId) { if (phaseId == PREPARE) { super.collectionPhase(phaseId); msTrace.prepare(); msSpace.prepare(true); return; } if (phaseId == CLOSURE) { msTrace.prepare(); return; } if (phaseId == RELEASE) { msTrace.release(); msSpace.release(); super.collectionPhase(phaseId); return; } super.collectionPhase(phaseId); } /***************************************************************************** * Accounting */ /** * {@inheritDoc} * The superclass accounts for its spaces, we just * augment this with the mark-sweep space's contribution. */ @Override public int getPagesUsed() { return (msSpace.reservedPages() + super.getPagesUsed()); } /***************************************************************************** * Miscellaneous */ /** * {@inheritDoc} */ @Override public boolean willNeverMove(ObjectReference object) { if (Space.isInSpace(MARK_SWEEP, object)) return true; return super.willNeverMove(object); } @Interruptible @Override protected void registerSpecializedMethods() { TransitiveClosure.registerSpecializedScan(SCAN_MARK, MSTraceLocal.class); super.registerSpecializedMethods(); } }