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org.mmtk.plan.marksweep
Class MS

java.lang.Object
  extended by org.mmtk.plan.Plan
      extended by org.mmtk.plan.Simple
          extended by org.mmtk.plan.StopTheWorld
              extended by org.mmtk.plan.marksweep.MS
All Implemented Interfaces:
Constants
Direct Known Subclasses:
Poisoned, StickyMS
public class MS
extends StopTheWorld

This class implements the global state of a simple mark-sweep collector. All plans make a clear distinction between global and thread-local 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.

Field Summary
static int MARK_SWEEP
           
static MarkSweepSpace msSpace
          Class variables
 Trace msTrace
          Instance variables
static int SCAN_MARK
           
 
Fields inherited from class org.mmtk.plan.StopTheWorld
postSanityPhase, preSanityPhase
 
Fields inherited from class org.mmtk.plan.Simple
CLOSURE, collection, collectionAttempt, COMPLETE, completeClosurePhase, FINALIZABLE, finishPhase, FORWARD, FORWARD_FINALIZABLE, FORWARD_REFS, forwardPhase, INITIATE, initPhase, PHANTOM_REFS, POST_SANITY_PLACEHOLDER, PRE_SANITY_PLACEHOLDER, PRECOPY, PREPARE, PREPARE_STACKS, prepareStacks, refTypeClosurePhase, RELEASE, rootClosurePhase, ROOTS, SANITY_BUILD_TABLE, SANITY_CHECK_TABLE, SANITY_COPY_ROOTS, SANITY_PREPARE, SANITY_RELEASE, SANITY_ROOTS, SANITY_SET_POSTGC, SANITY_SET_PREGC, sanityBuildPhase, sanityCheckPhase, SET_COLLECTION_KIND, SOFT_REFS, STACK_ROOTS, WEAK_REFS, WEAK_TRACK_REFS
 
Fields inherited from class org.mmtk.plan.Plan
ALLOC_CODE, ALLOC_COLD_CODE, ALLOC_DEFAULT, ALLOC_GCSPY, ALLOC_HOT_CODE, ALLOC_IMMORTAL, ALLOC_LARGE_CODE, ALLOC_LOS, ALLOC_NON_MOVING, ALLOC_NON_REFERENCE, ALLOC_PRIMITIVE_LOS, ALLOC_STACK, allocationSiteCount, ALLOCATORS, awaitingAsyncCollection, collectionTrigger, DEFAULT_MAX_NURSERY, DEFAULT_MIN_NURSERY, DEFAULT_POLL_FREQUENCY, DEFAULT_SITE, emergencyCollection, GATHER_WRITE_BARRIER_STATS, GC_PREPARE, GC_PROPER, HEAP_FULL_MINIMUM, HEAP_FULL_PERCENTAGE, IMMORTAL, immortalSpace, insideHarness, LARGE_CODE, largeCodeSpace, LOS, loSpace, MAX_COLLECTION_ATTEMPTS, MAX_NON_LOS_COPY_BYTES, MAX_NON_LOS_DEFAULT_ALLOC_BYTES, MAX_NON_LOS_NONMOVING_ALLOC_BYTES, META, META_DATA_POLL_FREQUENCY, metaDataSpace, NEEDS_LOG_BIT_IN_HEADER, NON_MOVING, NON_PARTICIPANT, nonMovingSpace, NOT_IN_GC, PLOS_FRAC, requiredAtStart, SANITY, sanityChecker, sanitySpace, SCAN_BOOT_IMAGE, SMALL_CODE, smallCodeSpace, stacksPrepared, timeCap, totalTime, USE_CODE_SPACE, VM_SPACE, vmSpace
 
Fields inherited from interface org.mmtk.utility.Constants
ALIGNMENT_VALUE, ARRAY_ELEMENT, BITS_IN_ADDRESS, BITS_IN_BYTE, BITS_IN_CHAR, BITS_IN_INT, BITS_IN_PAGE, BITS_IN_SHORT, BITS_IN_WORD, BYTES_IN_ADDRESS, BYTES_IN_BYTE, BYTES_IN_CHAR, BYTES_IN_INT, BYTES_IN_KBYTE, BYTES_IN_MBYTE, BYTES_IN_PAGE, BYTES_IN_SHORT, BYTES_IN_WORD, CARD_MASK, CARD_META_PAGES_PER_REGION, INSTANCE_FIELD, LOG_BITS_IN_ADDRESS, LOG_BITS_IN_BYTE, LOG_BITS_IN_CHAR, LOG_BITS_IN_INT, LOG_BITS_IN_PAGE, LOG_BITS_IN_SHORT, LOG_BITS_IN_WORD, LOG_BYTES_IN_ADDRESS, LOG_BYTES_IN_ADDRESS_SPACE, LOG_BYTES_IN_BYTE, LOG_BYTES_IN_CHAR, LOG_BYTES_IN_INT, LOG_BYTES_IN_KBYTE, LOG_BYTES_IN_MBYTE, LOG_BYTES_IN_PAGE, LOG_BYTES_IN_SHORT, LOG_BYTES_IN_WORD, LOG_CARD_BYTES, LOG_CARD_GRAIN, LOG_CARD_META_BYTES, LOG_CARD_META_PAGES, LOG_CARD_META_SIZE, LOG_CARD_UNITS, LOG_MIN_ALIGNMENT, MAX_ALIGNMENT, MAX_BYTES_PADDING, MAX_INT, MIN_ALIGNMENT, MIN_INT, SUPPORT_CARD_SCANNING
 
Constructor Summary
MS()
           
 
Method Summary
 void collectionPhase(short phaseId)
          Perform a (global) collection phase.
 int getPagesRequired()
          Calculate the number of pages a collection is required to free to satisfy outstanding allocation requests.
 int getPagesUsed()
          Return the number of pages reserved for use given the pending allocation.
protected  void registerSpecializedMethods()
          Register specialized methods.
 boolean willNeverMove(ObjectReference object)
          Can this object ever move.
 
Methods inherited from class org.mmtk.plan.StopTheWorld
postBoot
 
Methods inherited from class org.mmtk.plan.Simple
replacePhase, replacePlaceholderPhase
 
Methods inherited from class org.mmtk.plan.Plan
availableMemory, boot, bootTimeWriteBarrier, checkForAsyncCollection, collectionComplete, collectionRequired, concurrentCollectionRequired, forceFullHeapCollection, freeMemory, fullyBooted, gcInProgress, gcInProgressProper, getAllocationSite, getCollectionReserve, getHeapFullThreshold, getMetaDataPagesUsed, getPagesAvail, getPagesReserved, getSpecializedScanClass, getTimeCap, getTotalPages, harnessBegin, harnessEnd, insertPhaseAfter, isCollectionTriggered, isCurrentGCNursery, isEmergencyCollection, isInitialized, lastCollectionFailed, lastCollectionFullHeap, lastCollectionWasExhaustive, loadObjectReference, notifyExit, poll, printDetailedTiming, printPostStats, printPreStats, printUsedPages, reservedMemory, sanityExpectedRC, sanityLinearScan, setAwaitingAsyncCollection, setCollectionTrigger, setCollectionTriggered, setGCStatus, stacksPrepared, startGCspyServer, storeObjectReference, stressTestGCRequired, totalMemory, usedMemory
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

msSpace

public static final MarkSweepSpace msSpace
Class variables

MARK_SWEEP

public static final int MARK_SWEEP

SCAN_MARK

public static final int SCAN_MARK
See Also:
Constant Field Values

msTrace

public final Trace msTrace
Instance variables

Constructor Detail

MS

public MS()
Method Detail

collectionPhase

public void collectionPhase(short phaseId)
Perform a (global) collection phase.

Overrides:
collectionPhase in class Simple
Parameters:
phaseId - Collection phase to execute.

getPagesUsed

public int getPagesUsed()
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.

Overrides:
getPagesUsed in class Plan
Returns:
The number of pages reserved given the pending allocation, excluding space reserved for copying.

getPagesRequired

public int getPagesRequired()
Calculate the number of pages a collection is required to free to satisfy outstanding allocation requests.

Overrides:
getPagesRequired in class Plan
Returns:
the number of pages a collection is required to free to satisfy outstanding allocation requests.

willNeverMove

public boolean willNeverMove(ObjectReference object)
Description copied from class: Plan
Can this object ever move. Used by the VM to make decisions about whether it needs to copy IO buffers etc.

Overrides:
willNeverMove in class Plan
Parameters:
object - Object in question
Returns:
True if the object will never move
See Also:
Plan.willNeverMove(org.vmmagic.unboxed.ObjectReference)

registerSpecializedMethods

protected void registerSpecializedMethods()
Register specialized methods.

Overrides:
registerSpecializedMethods in class Plan
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