| /* |
| * 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.copyms; |
| |
| import org.mmtk.plan.*; |
| import org.mmtk.policy.CopySpace; |
| import org.mmtk.policy.MarkSweepSpace; |
| import org.mmtk.policy.Space; |
| import org.mmtk.utility.heap.VMRequest; |
| import org.mmtk.utility.options.Options; |
| import org.mmtk.utility.sanitychecker.SanityChecker; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.ObjectReference; |
| |
| /** |
| * This class implements the global state of a full-heap collector |
| * with a copying nursery and mark-sweep mature space. Unlike a full |
| * generational collector, there is no write barrier, no remembered set, and |
| * every collection is full-heap. |
| * |
| * 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. |
| * |
| * 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 CopyMS extends StopTheWorld { |
| |
| /**************************************************************************** |
| * Constants |
| */ |
| |
| /**************************************************************************** |
| * Class variables |
| */ |
| public static final CopySpace nurserySpace = new CopySpace("nursery", DEFAULT_POLL_FREQUENCY, false, VMRequest.create(0.15f, true)); |
| public static final MarkSweepSpace msSpace = new MarkSweepSpace("ms", DEFAULT_POLL_FREQUENCY, VMRequest.create()); |
| |
| public static final int NURSERY = nurserySpace.getDescriptor(); |
| public static final int MARK_SWEEP = msSpace.getDescriptor(); |
| |
| public static final int ALLOC_NURSERY = ALLOC_DEFAULT; |
| public static final int ALLOC_MS = StopTheWorld.ALLOCATORS + 1; |
| |
| public static final int SCAN_COPYMS = 0; |
| |
| /**************************************************************************** |
| * Instance variables |
| */ |
| |
| public final Trace trace; |
| |
| /** |
| * Constructor. |
| */ |
| public CopyMS() { |
| trace = new Trace(metaDataSpace); |
| } |
| |
| |
| /***************************************************************************** |
| * Collection |
| */ |
| |
| /** |
| * Perform a (global) collection phase. |
| * |
| * @param phaseId Collection phase to execute. |
| */ |
| @Inline |
| public final void collectionPhase(short phaseId) { |
| if (phaseId == PREPARE) { |
| super.collectionPhase(phaseId); |
| trace.prepare(); |
| msSpace.prepare(true); |
| nurserySpace.prepare(true); |
| return; |
| } |
| if (phaseId == CLOSURE) { |
| trace.prepare(); |
| return; |
| } |
| if (phaseId == RELEASE) { |
| trace.release(); |
| msSpace.release(); |
| nurserySpace.release(); |
| super.collectionPhase(phaseId); |
| return; |
| } |
| |
| super.collectionPhase(phaseId); |
| } |
| |
| /** |
| * This method controls the triggering of a GC. It is called periodically |
| * during allocation. Returns true to trigger a collection. |
| * |
| * @param spaceFull Space request failed, must recover pages within 'space'. |
| * @return True if a collection is requested by the plan. |
| */ |
| public final boolean collectionRequired(boolean spaceFull) { |
| boolean nurseryFull = nurserySpace.reservedPages() > Options.nurserySize.getMaxNursery(); |
| |
| return super.collectionRequired(spaceFull) || nurseryFull; |
| } |
| |
| /***************************************************************************** |
| * |
| * Accounting |
| */ |
| |
| /** |
| * Return the number of pages reserved for use given the pending |
| * allocation. |
| * |
| * @return The number of pages reserved given the pending |
| * allocation, excluding space reserved for copying. |
| */ |
| public int getPagesUsed() { |
| return super.getPagesUsed() + |
| msSpace.reservedPages() + |
| nurserySpace.reservedPages(); |
| } |
| |
| /** |
| * Return the number of pages reserved for collection. |
| * For mark sweep this is a fixed fraction of total pages. |
| * |
| * @return The number of pages reserved given the pending |
| * allocation, including space reserved for collection. |
| */ |
| public int getCollectionReserve() { |
| return nurserySpace.reservedPages() + super.getCollectionReserve(); |
| } |
| |
| /** |
| * @return The number of pages available for allocation, <i>assuming |
| * all future allocation is to the nursery</i>. |
| */ |
| public final int getPagesAvail() { |
| return (getTotalPages() - getPagesReserved()) >> 1; |
| } |
| |
| /** |
| * 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() + msSpace.requiredPages() + |
| (nurserySpace.requiredPages() << 1); |
| } |
| |
| /** |
| * Return the expected reference count. For non-reference counting |
| * collectors this becomes a true/false relationship. |
| * |
| * @param object The object to check. |
| * @param sanityRootRC The number of root references to the object. |
| * @return The expected (root excluded) reference count. |
| */ |
| public int sanityExpectedRC(ObjectReference object, int sanityRootRC) { |
| Space space = Space.getSpaceForObject(object); |
| |
| // Nursery |
| if (space == CopyMS.nurserySpace) { |
| return SanityChecker.DEAD; |
| } |
| |
| return space.isReachable(object) ? SanityChecker.ALIVE : SanityChecker.DEAD; |
| } |
| |
| /** |
| * Register specialized methods. |
| */ |
| @Interruptible |
| protected void registerSpecializedMethods() { |
| TransitiveClosure.registerSpecializedScan(SCAN_COPYMS, CopyMSTraceLocal.class); |
| super.registerSpecializedMethods(); |
| } |
| } |