Hesham/wintun
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Minimize TransitionLock when receiving packets

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We do not need to share-lock the TransitionLock for the whole life of
receiver thread.

Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman 2019-07-18 14:51:15 +02:00
parent 9bf25d873b
commit f5eadb50c4
1 changed files with 11 additions and 13 deletions
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24
wintun.c
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@ -279,7 +279,6 @@ TunSendNetBufferLists(
KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
LONG Flags = InterlockedGet(&Ctx->Flags);
NDIS_STATUS Status;
if ((Status = NDIS_STATUS_ADAPTER_REMOVED, !(Flags & TUN_FLAGS_PRESENT)) ||
(Status = NDIS_STATUS_PAUSED, !(Flags & TUN_FLAGS_RUNNING)) ||
@ -399,24 +398,22 @@ _Function_class_(KSTART_ROUTINE)
static void
TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
{
KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
TUN_RING *Ring = Ctx->Device.Receive.Ring;
ULONG RingCapacity = Ctx->Device.Receive.Capacity;
const ULONG SpinMax = 10000 * 50 / KeQueryTimeIncrement(); /* 50ms */
VOID *Events[] = { &Ctx->Device.Disconnected, Ctx->Device.Receive.TailMoved };
ASSERT(RTL_NUMBER_OF(Events) <= THREAD_WAIT_OBJECTS);
ULONG RingHead = InterlockedGetU(&Ring->Head);
if (RingHead >= RingCapacity)
goto cleanup;
while (!KeReadStateEvent(&Ctx->Device.Disconnected))
{
/* Get next packet from the ring. */
ULONG RingHead = InterlockedGetU(&Ring->Head);
if (RingHead >= RingCapacity)
break;
ULONG RingTail = InterlockedGetU(&Ring->Tail);
if (RingHead == RingTail)
{
ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
ULONG64 SpinStart;
KeQueryTickCount(&SpinStart);
for (;;)
@ -444,13 +441,11 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
KeWaitForMultipleObjects(
RTL_NUMBER_OF(Events), Events, WaitAny, Executive, KernelMode, FALSE, NULL, NULL);
InterlockedExchange(&Ring->Alertable, FALSE);
Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
continue;
}
InterlockedExchange(&Ring->Alertable, FALSE);
KeClearEvent(Ctx->Device.Receive.TailMoved);
}
Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
}
if (RingTail >= RingCapacity)
break;
@ -494,6 +489,7 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
NET_BUFFER_LIST_STATUS(Nbl) = NDIS_STATUS_SUCCESS;
/* Inform NDIS of the packet. */
KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
if ((InterlockedGet(&Ctx->Flags) & (TUN_FLAGS_PRESENT | TUN_FLAGS_RUNNING)) !=
(TUN_FLAGS_PRESENT | TUN_FLAGS_RUNNING))
goto cleanupFreeNbl;
@ -505,23 +501,25 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
NDIS_DEFAULT_PORT_NUMBER,
1,
NDIS_RECEIVE_FLAGS_DISPATCH_LEVEL | NDIS_RECEIVE_FLAGS_RESOURCES | NDIS_RECEIVE_FLAGS_SINGLE_ETHER_TYPE);
ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
NdisFreeNetBufferList(Nbl);
InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCInOctets, PacketSize);
InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCInUcastOctets, PacketSize);
InterlockedIncrement64((LONG64 *)&Ctx->Statistics.ifHCInUcastPkts);
NdisFreeNetBufferList(Nbl);
goto nextPacket;
cleanupFreeNbl:
ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
NdisFreeNetBufferList(Nbl);
cleanupDiscardPacket:
InterlockedIncrement64((LONG64 *)&Ctx->Statistics.ifInDiscards);
nextPacket:
InterlockedExchangeU(&Ring->Head, TUN_RING_WRAP(RingHead + AlignedPacketSize, RingCapacity));
RingHead = TUN_RING_WRAP(RingHead + AlignedPacketSize, RingCapacity);
InterlockedExchangeU(&Ring->Head, RingHead);
}
cleanup:
InterlockedExchangeU(&Ring->Head, MAXULONG);
ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
}
_IRQL_requires_max_(PASSIVE_LEVEL)