| /* |
| * 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.immix; |
| |
| import org.mmtk.plan.*; |
| import org.mmtk.policy.Space; |
| import org.mmtk.policy.immix.ImmixSpace; |
| import org.mmtk.policy.immix.ObjectHeader; |
| import org.mmtk.utility.heap.VMRequest; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.*; |
| |
| /** |
| * This class implements the global state of an immix collector. |
| * |
| * See the PLDI'08 paper by Blackburn and McKinley for a description |
| * of the algorithm: http://doi.acm.org/10.1145/1375581.1375586 |
| * |
| * 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 or in Jikes RVM, Processors). Thus instance |
| * methods of PlanLocal allow fast, unsychronized access to functions such as |
| * allocation and collection. |
| * |
| * 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 Immix extends StopTheWorld { |
| |
| /**************************************************************************** |
| * Constants |
| */ |
| |
| /**************************************************************************** |
| * Class variables |
| */ |
| public static final ImmixSpace immixSpace = new ImmixSpace("immix", DEFAULT_POLL_FREQUENCY, VMRequest.create()); |
| public static final int IMMIX = immixSpace.getDescriptor(); |
| |
| public static final int SCAN_IMMIX = 0; |
| public static final int SCAN_DEFRAG = 1; |
| |
| /**************************************************************************** |
| * Instance variables |
| */ |
| |
| public final Trace immixTrace = new Trace(metaDataSpace); |
| /** will the next collection collect the whole heap? */ |
| public boolean nextGCWholeHeap = true; |
| /** will this collection collect the whole heap */ |
| public boolean collectWholeHeap = nextGCWholeHeap; |
| protected boolean lastGCWasDefrag = false; |
| |
| /** |
| * Constructor. |
| * |
| */ |
| public Immix() { |
| } |
| |
| /***************************************************************************** |
| * |
| * Collection |
| */ |
| |
| /** |
| * Perform a (global) collection phase. |
| * |
| * @param phaseId Collection phase to execute. |
| */ |
| @Inline |
| public void collectionPhase(short phaseId) { |
| if (phaseId == SET_COLLECTION_KIND) { |
| super.collectionPhase(phaseId); |
| immixSpace.decideWhetherToDefrag(emergencyCollection, collectWholeHeap, collectionAttempt, collectionTrigger); |
| return; |
| } |
| |
| if (phaseId == PREPARE) { |
| super.collectionPhase(phaseId); |
| immixTrace.prepare(); |
| immixSpace.prepare(true); |
| return; |
| } |
| |
| if (phaseId == CLOSURE) { |
| immixTrace.prepare(); |
| return; |
| } |
| |
| if (phaseId == RELEASE) { |
| immixTrace.release(); |
| lastGCWasDefrag = immixSpace.release(true); |
| super.collectionPhase(phaseId); |
| return; |
| } |
| |
| super.collectionPhase(phaseId); |
| } |
| |
| /** |
| * @return Whether last GC was an exhaustive attempt to collect the heap. For many collectors this is the same as asking whether the last GC was a full heap collection. |
| */ |
| @Override |
| public boolean lastCollectionWasExhaustive() { |
| return lastGCWasDefrag; |
| } |
| |
| /***************************************************************************** |
| * |
| * Accounting |
| */ |
| |
| /** |
| * Return the number of pages reserved for use given the pending |
| * allocation. The superclass accounts for its spaces, we just |
| * augment this with the mark-sweep space's contribution. |
| * |
| * @return The number of pages reserved given the pending |
| * allocation, excluding space reserved for copying. |
| */ |
| public int getPagesUsed() { |
| return immixSpace.reservedPages() + super.getPagesUsed(); |
| } |
| |
| /** |
| * Calculate the number of pages a collection is required to free to satisfy |
| * outstanding allocation requests. |
| * |
| * @return the number of pages a collection is required to free to satisfy |
| * outstanding allocation requests. |
| */ |
| public int getPagesRequired() { |
| return super.getPagesRequired() + immixSpace.requiredPages(); |
| } |
| |
| /** |
| * @see org.mmtk.plan.Plan#willNeverMove |
| * |
| * @param object Object in question |
| * @return True if the object will never move |
| */ |
| @Override |
| public boolean willNeverMove(ObjectReference object) { |
| if (Space.isInSpace(IMMIX, object)) { |
| ObjectHeader.pinObject(object); |
| return true; |
| } else |
| return super.willNeverMove(object); |
| } |
| |
| /** |
| * Register specialized methods. |
| */ |
| @Interruptible |
| protected void registerSpecializedMethods() { |
| TransitiveClosure.registerSpecializedScan(SCAN_IMMIX, ImmixTraceLocal.class); |
| TransitiveClosure.registerSpecializedScan(SCAN_DEFRAG, ImmixDefragTraceLocal.class); |
| super.registerSpecializedMethods(); |
| } |
| } |