@ -18,7 +18,8 @@ type LockTable[T comparable] struct {
type LockEntry struct {
mu sync . Mutex
waiters [ ] * ActiveLock // ordered waiters that are blocked by exclusive locks
activeLockOwnerCount int32
activeSharedLockOwnerCount int32
activeExclusiveLockOwnerCount int32
lockType LockType
cond * sync . Cond
}
@ -34,6 +35,7 @@ type ActiveLock struct {
ID int64
isDeleted bool
intention string // for debugging
lockType LockType
}
func NewLockTable [ T comparable ] ( ) * LockTable [ T ] {
@ -42,9 +44,9 @@ func NewLockTable[T comparable]() *LockTable[T] {
}
}
func ( lt * LockTable [ T ] ) NewActiveLock ( intention string ) * ActiveLock {
func ( lt * LockTable [ T ] ) NewActiveLock ( intention string , lockType LockType ) * ActiveLock {
id := atomic . AddInt64 ( & lt . lockIdSeq , 1 )
l := & ActiveLock { ID : id , intention : intention }
l := & ActiveLock { ID : id , intention : intention , lockType : lockType }
return l
}
@ -65,7 +67,7 @@ func (lt *LockTable[T]) AcquireLock(intention string, key T, lockType LockType)
entry . mu . Lock ( )
if len ( entry . waiters ) > 0 || lockType == ExclusiveLock {
if glog . V ( 4 ) {
fmt . Printf ( "ActiveLock %d %s wait for %+v type=%v with waiters %d active %d.\n" , lock . ID , lock . intention , key , lockType , len ( entry . waiters ) , entry . activeLockOwnerCount )
fmt . Printf ( "ActiveLock %d %s wait for %+v type=%v with waiters %d active r%d w %d.\n" , lock . ID , lock . intention , key , lockType , len ( entry . waiters ) , entry . activeSharedLockOwnerCount , entry . activeExclus iveLockOwnerCount )
if len ( entry . waiters ) > 0 {
for _ , waiter := range entry . waiters {
fmt . Printf ( " %d" , waiter . ID )
@ -75,11 +77,11 @@ func (lt *LockTable[T]) AcquireLock(intention string, key T, lockType LockType)
}
entry . waiters = append ( entry . waiters , lock )
if lockType == ExclusiveLock {
for ! lock . isDeleted && ( ( len ( entry . waiters ) > 0 && lock . ID != entry . waiters [ 0 ] . ID ) || entry . activeLockOwnerCount > 0 ) {
for ! lock . isDeleted && ( ( len ( entry . waiters ) > 0 && lock . ID != entry . waiters [ 0 ] . ID ) || entry . activeExclusiveLockOwnerCount > 0 || entry . activeShared LockOwnerCount > 0 ) {
entry . cond . Wait ( )
}
} else {
for ! lock . isDeleted && ( len ( entry . waiters ) > 0 && lock . ID != entry . waiters [ 0 ] . ID ) {
for ! lock . isDeleted && ( len ( entry . waiters ) > 0 && lock . ID != entry . waiters [ 0 ] . ID ) || entry . activeExclusiveLockOwnerCount > 0 {
entry . cond . Wait ( )
}
}
@ -93,7 +95,7 @@ func (lt *LockTable[T]) AcquireLock(intention string, key T, lockType LockType)
// Otherwise, grant the lock
entry . lockType = lockType
if glog . V ( 4 ) {
fmt . Printf ( "ActiveLock %d %s locked %+v type=%v with waiters %d active %d.\n" , lock . ID , lock . intention , key , lockType , len ( entry . waiters ) , entry . activeLockOwnerCount )
fmt . Printf ( "ActiveLock %d %s locked %+v type=%v with waiters %d active r%d w %d.\n" , lock . ID , lock . intention , key , lockType , len ( entry . waiters ) , entry . activeSharedLockOwnerCount , entry . activeExclus iveLockOwnerCount )
if len ( entry . waiters ) > 0 {
for _ , waiter := range entry . waiters {
fmt . Printf ( " %d" , waiter . ID )
@ -101,7 +103,11 @@ func (lt *LockTable[T]) AcquireLock(intention string, key T, lockType LockType)
fmt . Printf ( "\n" )
}
}
entry . activeLockOwnerCount ++
if lock . lockType == ExclusiveLock {
entry . activeExclusiveLockOwnerCount ++
} else {
entry . activeSharedLockOwnerCount ++
}
entry . mu . Unlock ( )
return lock
@ -134,7 +140,7 @@ func (lt *LockTable[T]) ReleaseLock(key T, lock *ActiveLock) {
}
if glog . V ( 4 ) {
fmt . Printf ( "ActiveLock %d %s unlocked %+v type=%v with waiters %d active %d.\n" , lock . ID , lock . intention , key , entry . lockType , len ( entry . waiters ) , entry . activeLockOwnerCount )
fmt . Printf ( "ActiveLock %d %s unlocked %+v type=%v with waiters %d active r%d w %d.\n" , lock . ID , lock . intention , key , entry . lockType , len ( entry . waiters ) , entry . activeSharedLockOwnerCount , entry . activeExclus iveLockOwnerCount )
if len ( entry . waiters ) > 0 {
for _ , waiter := range entry . waiters {
fmt . Printf ( " %d" , waiter . ID )
@ -142,7 +148,11 @@ func (lt *LockTable[T]) ReleaseLock(key T, lock *ActiveLock) {
fmt . Printf ( "\n" )
}
}
entry . activeLockOwnerCount --
if lock . lockType == ExclusiveLock {
entry . activeExclusiveLockOwnerCount --
} else {
entry . activeSharedLockOwnerCount --
}
// Notify the next waiter
entry . cond . Broadcast ( )