NT4/private/ntos/afd/spinlock.txt
2020-09-30 17:12:29 +02:00

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AfdSpinLock Usage
~~~~~~~~~~~~~~~~~
ACCEPT.C
Function: AfdDeferAccept
Protects: Endpoint->Common.VcListening.UnacceptedConnectionListHead
Synopsis: Used when deferring an accept (putting a connection back
on the endpoint's unaccepted connection queue).
Strategy: None. Deferring accepted connections is a very low
frequency operation (and is impossible in WinSock 1.1).
BIND.C
Function: AfdRestartGetAddress
Protects: Endpoint->LocalAddress[Length]
Synopsis: Used when allocating an endpoint's local address buffer
to prevent multiple processors from allocating the buffer.
Strategy: None. AfdGetAddress is only called during bind() and
getsockname() APIs. The bind() call is certainly more
interesting than getsockname(), but even bind() is only
called once per socket, so it is unlikely there would be
any benefit in tuning this.
BLKCONN.C
Function: AfdAddFreeConnection
Protects: Endpoint->Common.VcListening.FreeConnectionListHead
Synopsis: Used when adding free connections to the endpoint's
free connection queue.
Strategy: Use SLIST for free connection queue.
Function: AfdFreeConnection
Protects: Endpoint->Common.VcListening.FreeConnectionListHead
Synopsis: Used when appending a reused connection to the endpoint's
free connection queue.
Strategy: Use SLIST for free connection queue.
Function: AfdDereferenceConnection
Protects: Connection->ReferenceCount
Synopsis: Synchronizes access to reference count member.
Strategy: Use InterlockedDecrement. If updated value is now zero,
then acquire AfdSpinLock, and recheck the value for zero.
If it's still zero, do the usual dereference stuff. This
will eliminate all spinlock acquisitions on reference/
dereference except the *last* dereference.
Function: AfdGetFreeConnection
Protects: Endpoint->Common.VcListening.FreeConnectionListHead
Synopsis: Used when removing a free connection from the endpoint's
free connection queue.
Strategy: Use SLIST for free connection queue.
Function: AfdGetReturnedConnection
Protects: Endpoint->Common.VcListening.ReturnedConnectionListHead
Synopsis: Used when scanning the returned connection queue for a
specific sequence number.
Strategy: None (for now).
Function: AfdReferenceConnection
Protects: Connection->ReferenceCount
Synopsis: Synchronizes access to reference count member.
Strategy: Use InterlockedIncrement instead.
BLKENDP.C
Function: AfdFreeQueuedConnections
Protects: Endpoint->Common.VcListening.UnacceptedConnectionListHead
Synopsis: Used when puring the endpoint's unaccepted connection
queue.
Strategy: None (for now).
Function: AfdDereferenceEndpoint
Protects: Endpoint->ReferenceCount
Synopsis: Synchronizes access to reference count member.
Strategy: Use InterlockedDecrement. If updated value is now zero,
then acquire AfdSpinLock, and recheck the value for zero.
If it's still zero, do the usual dereference stuff. This
will eliminate all spinlock acquisitions on reference/
dereference except the *last* dereference.
Function: AfdReferenceEndpoint
Protects: Endpoint->ReferenceCount
Synopsis: Synchronizes access to reference count member.
Strategy: Use InterlockedIncrement instead.
CLOSE.C
Function: AfdCleanup
Protects:
Synopsis:
Strategy:
CONNECT.C
Function: AfdSetupConnectDataBuffers
Protects: Endpoint->ConnectDataBuffers
Synopsis: Used to guard connect data buffers when they're moved
from an endpoint to a connection.
Strategy: Do the "double compare" trick to avoid acquiring the
spinlock if there are no connect data buffers on the
endpoint.
Function: AfdRestartConnect
Protects: Connection->ConnectDataBuffers
Synopsis: Used to guard connect data buffers after a connect
completes.
Strategy: Do the "double compare" trick to avoid acquiring the
spinlock if there are no connect data buffers on the
connection.
DISCONN.C
Function: AfdPartialDisconnect(1)
Protects: Endpoint->DisconnectMode
Synopsis: Used to guard the disconnect mode bits when shutting
down a datagram endpoint.
Strategy: Test a Bunch-O-Bits in the endpoint, and only if
at least one of these is nonzero acquire the spinlock,
then proceed with the current tests.
Function: AfdPartialDisconnect(2)
Protects: Connection->Common.Bufferring.Receive[Expedited]BytesTaken
Synopsis: Used to guard access to the byte counters in the connection
when receives are shutdown so that the connection can be
aborted if necessary.
Strategy: None (for now).
Function: AfdDisconnectEventHandler
Protects: Connection->ConnectDataBuffers
Synopsis: Used to guard disconnect data buffers when a disconnect
indication is received.
Strategy: Do the "double compare" trick to avoid acquiring the
spinlock if there are no connect data buffers on the
connection.
Function: AfdBeginAbort
Protects: Bunch-O-Crap
Synopsis:
Strategy:
Function: AfdBeginDisconnect
Protects: Bunch-O-Crap, including disconnect buffers
Synopsis:
Strategy:
Function: AfdRestartDisconnect
Protects: DisconnectContext->DisconnectListEntry
Synopsis: Guards access to AfdDisconnectListHead
Strategy: AfdDisconnectListHead no longer used. Nuke it!
LISTEN.C
Function: AfdWaitForListen
Protects:
Synopsis:
Strategy:
Function: AfdCancelWaitForListen
Protects:
Synopsis:
Strategy:
Function: AfdConnectEventHandler
Protects:
Synopsis:
Strategy:
Function: AfdRestartAccept
Protects:
Synopsis:
Strategy:
MISC.C
Function: AfdInsertNewEndpointInList
Protects:
Synopsis:
Strategy:
Function: AfdRemoveEndpointFromList
Protects:
Synopsis:
Strategy:
Function: AfdInterlockedRemoveEntryList
Protects:
Synopsis:
Strategy:
Function: AfdGetConnectData
Protects:
Synopsis:
Strategy:
Function: AfdSetConnectData
Protects:
Synopsis:
Strategy:
Function: AfdQueueWorkItem
Protects:
Synopsis:
Strategy:
Function: AfdDoWork
Protects:
Synopsis:
Strategy:
POLL.C
Function: AfdPoll
Protects:
Synopsis:
Strategy:
Function: AfdCancelPoll
Protects:
Synopsis:
Strategy:
Function: AfdIndicatePollEvent
Protects:
Synopsis:
Strategy:
Function: AfdTimeoutPoll
Protects:
Synopsis:
Strategy:
RECEIVE.C
Function: AfdReceive
Protects:
Synopsis:
Strategy:
Function: AfdRestartReceive
Protects:
Synopsis:
Strategy:
Function: AfdReceiveEventHandler
Protects:
Synopsis:
Strategy:
Function: AfdReceiveExpeditedEventHandler
Protects:
Synopsis:
Strategy:
Function: AfdQueryReceiveInformation
Protects:
Synopsis:
Strategy:
SEND.C
Function: AfdRestartBufferSend
Protects: Connection->VcDisconnectIrp
Synopsis: Used to grab the disconnect IRP off a connection.
Strategy: Use InterlockedExchange. Will require changes to
blkconn!AfdFreeConnection.
AfdBufferSpinLock Usage
~~~~~~~~~~~~~~~~~~~~~~~
BUFFER.C
Function: AfdGetBuffer
Protects: Afd{Small|Medium|Large}BufferListHead
Synopsis: Serializes access to the various buffer lists.
Strategy: Use DaveC's SLIST instead. We'll still need the spinlock
for PPC.
Function: AfdReturnBuffer
Protects: Afd{Small|Medium|Large}BufferListHead
Synopsis: Serializes access to the various buffer lists.
Strategy: Use DaveC's SLIST instead. We'll still need the spinlock
for PPC.
Endpoint->SpinLock Usage
~~~~~~~~~~~~~~~~~~~~~~~~
ACCEPT.C
Function: AfdAcceptCore
Protects:
Synopsis:
Strategy:
BLKCONN.C
Function: AfdAddConnectedReference
Protects: Connection->ConnectedReferenceAdded
Synopsis:
Strategy:
Function: AfdDeleteConnectedReference
Protects:
Synopsis:
Strategy:
CLOSE.C
Function: AfdCleanup
Protects: Endpoint->{Receive|Peek}DatagramIrpListHead,
Endpoint->Vc{Receive|Send}IrpListHead,
Connection->CleanupBegun,
Endpoint->TransmitIrp
Synopsis:
Strategy:
CONNECT.C
Function: AfdDoDatagramConnect
Protects: Endpoint->Common.Datagram.RemoteAddress[Length]
Synopsis:
Strategy:
Function: AfdRestartConnect
Protects: Connection->ConnectedReferenceAdded
Synopsis:
Strategy:
Function: AfdEnabledFailedConnectEvent
Protects: Endpoint->EventsEnabled
Synopsis:
Strategy:
DISCONN.C
Function: AfdDisconnectEventHandler
Protects: Connection->Vc{Receive|Send}IrpListHead,
Connection->VcByteCounts
Synopsis:
Strategy:
Function: AfdBeginAbort
Protects: Connection->Vc{Receive|Send}IrpListHead,
Synopsis:
Strategy:
Function: AfdRestartAbort
Protects: Connection->Vc{Receive|Send}IrpListHead,
Synopsis:
Strategy:
EVENTSEL.C
Function: AfdEventSelect
Protects: Endpoint->EventSelectStuff
Synopsis:
Strategy:
Function: AfdEnumNetworkEvents
Protects: Endpoint->EventSelectStuff
Synopsis:
Strategy:
FASTIO.C
Function:
Protects:
Synopsis:
Strategy:
POLL.C
Function:
Protects:
Synopsis:
Strategy:
RECEIVE.C
Function:
Protects:
Synopsis:
Strategy:
RECVDG.C
Function:
Protects:
Synopsis:
Strategy:
RECVVC.C
Function:
Protects:
Synopsis:
Strategy:
SEND.C
Function:
Protects:
Synopsis:
Strategy:
TRANFILE.C
Function:
Protects:
Synopsis:
Strategy: