| /* |
| * 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.semispace; |
| |
| import org.mmtk.plan.*; |
| import org.mmtk.policy.CopyLocal; |
| import org.mmtk.policy.LargeObjectLocal; |
| import org.mmtk.policy.Space; |
| import org.mmtk.utility.ForwardingWord; |
| import org.mmtk.vm.VM; |
| |
| import org.vmmagic.unboxed.*; |
| import org.vmmagic.pragma.*; |
| |
| /** |
| * This class implements <i>per-collector thread</i> behavior |
| * and state for the <i>SS</i> plan, which implements a full-heap |
| * semi-space collector.<p> |
| * |
| * Specifically, this class defines <i>SS</i> collection behavior |
| * (through <code>trace</code> and the <code>collectionPhase</code> |
| * method), and collection-time allocation (copying of objects).<p> |
| * |
| * See {@link SS} for an overview of the semi-space algorithm.<p> |
| * |
| * @see SS |
| * @see SSMutator |
| * @see StopTheWorldCollector |
| * @see CollectorContext |
| */ |
| @Uninterruptible |
| public class SSCollector extends StopTheWorldCollector { |
| |
| /**************************************************************************** |
| * Instance fields |
| */ |
| |
| protected final SSTraceLocal trace; |
| protected final CopyLocal ss; |
| protected final LargeObjectLocal los; |
| |
| /**************************************************************************** |
| * |
| * Initialization |
| */ |
| |
| /** |
| * Constructor |
| */ |
| public SSCollector() { |
| this(new SSTraceLocal(global().ssTrace)); |
| } |
| |
| /** |
| * Constructor |
| * @param tr The trace to use |
| */ |
| protected SSCollector(SSTraceLocal tr) { |
| ss = new CopyLocal(); |
| los = new LargeObjectLocal(Plan.loSpace); |
| trace = tr; |
| } |
| |
| /**************************************************************************** |
| * |
| * Collection-time allocation |
| */ |
| |
| /** |
| * Allocate space for copying an object (this method <i>does not</i> |
| * copy the object, it only allocates space) |
| * |
| * @param original A reference to the original object |
| * @param bytes The size of the space to be allocated (in bytes) |
| * @param align The requested alignment. |
| * @param offset The alignment offset. |
| * @return The address of the first byte of the allocated region |
| */ |
| @Inline |
| public Address allocCopy(ObjectReference original, int bytes, |
| int align, int offset, int allocator) { |
| if (allocator == Plan.ALLOC_LOS) { |
| if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(bytes > Plan.MAX_NON_LOS_COPY_BYTES); |
| return los.alloc(bytes, align, offset); |
| } else { |
| if (VM.VERIFY_ASSERTIONS) { |
| VM.assertions._assert(bytes <= Plan.MAX_NON_LOS_COPY_BYTES); |
| VM.assertions._assert(allocator == SS.ALLOC_SS); |
| } |
| return ss.alloc(bytes, align, offset); |
| } |
| } |
| |
| /** |
| * Perform any post-copy actions. |
| * |
| * @param object The newly allocated object |
| * @param typeRef the type reference for the instance being created |
| * @param bytes The size of the space to be allocated (in bytes) |
| */ |
| @Inline |
| public void postCopy(ObjectReference object, ObjectReference typeRef, |
| int bytes, int allocator) { |
| ForwardingWord.clearForwardingBits(object); |
| if (allocator == Plan.ALLOC_LOS) |
| Plan.loSpace.initializeHeader(object, false); |
| } |
| |
| /**************************************************************************** |
| * |
| * Collection |
| */ |
| |
| /** |
| * Perform a per-collector collection phase. |
| * |
| * @param phaseId The collection phase to perform |
| * @param primary Perform any single-threaded activities using this thread. |
| */ |
| @Inline |
| public void collectionPhase(short phaseId, boolean primary) { |
| if (phaseId == SS.PREPARE) { |
| // rebind the copy bump pointer to the appropriate semispace. |
| ss.rebind(SS.toSpace()); |
| los.prepare(true); |
| super.collectionPhase(phaseId, primary); |
| return; |
| } |
| |
| if (phaseId == SS.CLOSURE) { |
| trace.completeTrace(); |
| return; |
| } |
| |
| if (phaseId == SS.RELEASE) { |
| trace.release(); |
| los.release(true); |
| super.collectionPhase(phaseId, primary); |
| return; |
| } |
| |
| super.collectionPhase(phaseId, primary); |
| } |
| |
| |
| /**************************************************************************** |
| * |
| * Object processing and tracing |
| */ |
| |
| /** |
| * Return true if the given reference is to an object that is within |
| * one of the semi-spaces. |
| * |
| * @param object The object in question |
| * @return True if the given reference is to an object that is within |
| * one of the semi-spaces. |
| */ |
| public static boolean isSemiSpaceObject(ObjectReference object) { |
| return Space.isInSpace(SS.SS0, object) || Space.isInSpace(SS.SS1, object); |
| } |
| |
| /**************************************************************************** |
| * |
| * Miscellaneous |
| */ |
| |
| /** @return The active global plan as an <code>SS</code> instance. */ |
| @Inline |
| private static SS global() { |
| return (SS) VM.activePlan.global(); |
| } |
| |
| /** @return the current trace object. */ |
| public TraceLocal getCurrentTrace() { |
| return trace; |
| } |
| } |