org.jikesrvm.objectmodel

Class ThinLockConstants

java.lang.Object

org.jikesrvm.objectmodel.ThinLockConstants

public final class ThinLockConstants
extends Object

Constants used to implement thin locks.

A portion of a word, either in the object header or in some other location, is used to provide light weight synchronization operations. This class defines how the bits available for thin locks are allocated. Either a lock is in fat state, in which case it looks like 1Z..Z where Z..Z is the id of a heavy lock, or it is in thin state in which case it looks like 0I..IC..C where I is the thread id of the thread that owns the lock and C is the recursion count of the lock.

 aaaaTTTTTTTTTTbbbbb
 JavaHeader.NUM_THIN_LOCK_BITS = # of T's
 JavaHeader.THIN_LOCK_SHIFT = # of b's
 

Field Summary

Fields

Modifier and Type	Field and Description
static int	TL_DEDICATED_U16_OFFSET
static int	TL_DEDICATED_U16_SHIFT
static Word	TL_LOCK_COUNT_MASK
static int	TL_LOCK_COUNT_SHIFT
static Word	TL_LOCK_COUNT_UNIT
static Word	TL_LOCK_ID_MASK
static int	TL_LOCK_ID_SHIFT
static int	TL_NUM_BITS_RC
static int	TL_NUM_BITS_STAT
static int	TL_NUM_BITS_TID
static Word	TL_STAT_BIASABLE
static Word	TL_STAT_FAT
static Word	TL_STAT_MASK
static int	TL_STAT_SHIFT
static Word	TL_STAT_THIN
static Word	TL_THREAD_ID_MASK
static int	TL_THREAD_ID_SHIFT
static Word	TL_UNLOCK_MASK

Constructor Summary

Constructors

Modifier	Constructor and Description
private	ThinLockConstants()

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TL_NUM_BITS_STAT

public static final int TL_NUM_BITS_STAT

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Constant Field Values

TL_NUM_BITS_TID

public static final int TL_NUM_BITS_TID

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Constant Field Values

TL_NUM_BITS_RC

public static final int TL_NUM_BITS_RC

TL_THREAD_ID_SHIFT

public static final int TL_THREAD_ID_SHIFT

TL_LOCK_COUNT_SHIFT

public static final int TL_LOCK_COUNT_SHIFT

TL_STAT_SHIFT

public static final int TL_STAT_SHIFT

TL_LOCK_ID_SHIFT

public static final int TL_LOCK_ID_SHIFT

TL_DEDICATED_U16_OFFSET

public static final int TL_DEDICATED_U16_OFFSET

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Constant Field Values

TL_DEDICATED_U16_SHIFT

public static final int TL_DEDICATED_U16_SHIFT

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Constant Field Values

TL_LOCK_COUNT_UNIT

public static final Word TL_LOCK_COUNT_UNIT

TL_LOCK_COUNT_MASK

public static final Word TL_LOCK_COUNT_MASK

TL_THREAD_ID_MASK

public static final Word TL_THREAD_ID_MASK

TL_LOCK_ID_MASK

public static final Word TL_LOCK_ID_MASK

TL_STAT_MASK

public static final Word TL_STAT_MASK

TL_UNLOCK_MASK

public static final Word TL_UNLOCK_MASK

TL_STAT_BIASABLE

public static final Word TL_STAT_BIASABLE

TL_STAT_THIN

public static final Word TL_STAT_THIN

TL_STAT_FAT

public static final Word TL_STAT_FAT

Constructor Detail

ThinLockConstants

private ThinLockConstants()