| /* |
| * 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.stickyimmix; |
| |
| import org.mmtk.plan.*; |
| import org.mmtk.plan.immix.ImmixMutator; |
| |
| import org.mmtk.utility.deque.ObjectReferenceDeque; |
| import org.mmtk.vm.VM; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.*; |
| |
| /** |
| * This class implements <i>per-mutator thread</i> behavior |
| * and state for the <i>StickyImmix</i> plan, which implements a |
| * generational mark-sweep collector.<p> |
| * |
| * Specifically, this class defines <i>MS</i> mutator-time allocation |
| * and per-mutator thread collection semantics (flushing and restoring |
| * per-mutator allocator state).<p> |
| * * |
| * @see StickyImmix |
| * @see StickyImmixCollector |
| * @see MutatorContext |
| * @see Phase |
| */ |
| @Uninterruptible |
| public class StickyImmixMutator extends ImmixMutator { |
| |
| /**************************************************************************** |
| * Instance fields |
| */ |
| |
| private ObjectReferenceDeque modBuffer; |
| |
| /**************************************************************************** |
| * |
| * Initialization |
| */ |
| |
| /** |
| * Constructor |
| */ |
| public StickyImmixMutator() { |
| super(); |
| modBuffer = new ObjectReferenceDeque("mod buf", global().modPool); |
| } |
| |
| /**************************************************************************** |
| * |
| * Barriers |
| */ |
| |
| /** |
| * A new reference is about to be created. Take appropriate write |
| * barrier actions.<p> |
| * |
| * In this case, we remember the address of the source of the |
| * pointer if the new reference points into the nursery from |
| * non-nursery space. |
| * |
| * @param src The object into which the new reference will be stored |
| * @param slot The address into which the new reference will be |
| * stored. |
| * @param tgt The target of the new reference |
| * @param metaDataA A value that assists the host VM in creating a store |
| * @param metaDataB A value that assists the host VM in creating a store |
| * @param mode The mode of the store (eg putfield, putstatic etc) |
| */ |
| @Inline |
| public final void writeBarrier(ObjectReference src, Address slot, |
| ObjectReference tgt, Word metaDataA, Word metaDataB, int mode) { |
| if (Plan.logRequired(src)) |
| logSource(src); |
| VM.barriers.performWriteInBarrier(src, slot, tgt, metaDataA, metaDataB, mode); |
| } |
| |
| /** |
| * A number of references are about to be copied from object |
| * <code>src</code> to object <code>dst</code> (as in an array |
| * copy). Thus, <code>dst</code> is the mutated object. Take |
| * appropriate write barrier actions.<p> |
| * |
| * In this case, we remember the mutated source address range and |
| * will scan that address range at GC time. |
| * |
| * @param src The source of the values to copied |
| * @param srcOffset The offset of the first source address, in |
| * bytes, relative to <code>src</code> (in principle, this could be |
| * negative). |
| * @param dst The mutated object, i.e. the destination of the copy. |
| * @param dstOffset The offset of the first destination address, in |
| * bytes relative to <code>tgt</code> (in principle, this could be |
| * negative). |
| * @param bytes The size of the region being copied, in bytes. |
| * @return True if the update was performed by the barrier, false if |
| * left to the caller (always false in this case). |
| */ |
| @Inline |
| public final boolean writeBarrier(ObjectReference src, Offset srcOffset, |
| ObjectReference dst, Offset dstOffset, int bytes) { |
| if (Plan.logRequired(src)) |
| logSource(src); |
| return false; |
| } |
| |
| /** |
| * Add an object to the modified objects buffer and mark the |
| * object has having been logged. Since duplicate entries do |
| * not raise any correctness issues, we do <i>not</i> worry |
| * about synchronization and allow threads to race to log the |
| * object, potentially including it twice (unlike reference |
| * counting where duplicates would lead to incorrect reference |
| * counts). |
| * |
| * @param src The object to be logged |
| */ |
| private void logSource(ObjectReference src) { |
| Plan.markAsLogged(src); |
| modBuffer.push(src); |
| } |
| |
| /** |
| * Flush per-mutator remembered sets into the global remset pool. |
| */ |
| public final void flushRememberedSets() { |
| modBuffer.flushLocal(); |
| assertRemsetFlushed(); |
| } |
| |
| /** |
| * Assert that the remsets have been flushed. This is critical to |
| * correctness. We need to maintain the invariant that remset entries |
| * do not accrue during GC. If the host JVM generates barrier entires |
| * it is its own responsibility to ensure that they are flushed before |
| * returning to MMTk. |
| */ |
| public final void assertRemsetFlushed() { |
| if (VM.VERIFY_ASSERTIONS) { |
| VM.assertions._assert(modBuffer.isFlushed()); |
| } |
| } |
| |
| |
| /**************************************************************************** |
| * |
| * Collection |
| */ |
| |
| /** |
| * Perform a per-mutator collection phase. |
| * |
| * @param phaseId The collection phase to perform |
| * @param primary Perform any single-threaded activities using this thread. |
| */ |
| @Inline |
| public final void collectionPhase(short phaseId, boolean primary) { |
| if (phaseId == StickyImmix.PREPARE) { |
| flushRememberedSets(); |
| } |
| if (phaseId == StickyImmix.RELEASE) { |
| assertRemsetFlushed(); |
| } |
| |
| if (!global().collectWholeHeap) { |
| if (phaseId == StickyImmix.PREPARE) { |
| immix.prepare(); |
| return; |
| } |
| |
| if (phaseId == StickyImmix.RELEASE) { |
| immix.release(); |
| return; |
| } |
| } |
| |
| super.collectionPhase(phaseId, primary); |
| } |
| |
| /**************************************************************************** |
| * |
| * Miscellaneous |
| */ |
| |
| /** @return The active global plan as an <code>MSGen</code> instance. */ |
| @Inline |
| private static StickyImmix global() { |
| return (StickyImmix) VM.activePlan.global(); |
| } |
| } |