Fix DPC accounting

The DPC count is not zeroed when the event count is zeroed leading to some
odd looking stats. Also the DPC count should really be incremented by the
DPC itself to ensure serialization.

While in the neighbourhood, the ring notify functions in transmitter and
receiver look a little superfluous; they can easily be folded directly
into the DPC if the receiver code triggers the transmmitter DPC in the case
of a combined event channel.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>

diff --git a/src/xenvif/receiver.c b/src/xenvif/receiver.c
index 62ca1c8ecda9ab8138760f0c5cf5b5c98bf550d6..29877f237a40f3903dca0c4f8a4320a1465291e0 100644 (file)
--- a/src/xenvif/receiver.c
+++ b/src/xenvif/receiver.c
@@ -1981,16 +1981,6 @@ ReceiverRingPoll(
 #undef  XENVIF_RECEIVER_BATCH
 }
 
-static FORCEINLINE VOID
-__ReceiverRingNotify(
-    IN  PXENVIF_RECEIVER_RING   Ring
-    )
-{
-    __ReceiverRingAcquireLock(Ring);
-    ReceiverRingPoll(Ring);
-    __ReceiverRingReleaseLock(Ring);
-}
-
 static FORCEINLINE VOID
 __ReceiverRingUnmask(
     IN  PXENVIF_RECEIVER_RING   Ring
@@ -2023,8 +2013,6 @@ ReceiverRingDpc(
     )
 {
     PXENVIF_RECEIVER_RING   Ring = Context;
-    PXENVIF_RECEIVER        Receiver;
-    PXENVIF_FRONTEND        Frontend;
 
     UNREFERENCED_PARAMETER(Dpc);
     UNREFERENCED_PARAMETER(Argument1);
@@ -2032,16 +2020,14 @@ ReceiverRingDpc(
 
     ASSERT(Ring != NULL);
 
-    Receiver = Ring->Receiver;
-    Frontend = Receiver->Frontend;
+    Ring->Dpcs++;
 
-    if (Ring->Enabled) {
-        __ReceiverRingNotify(Ring);
-        if (!FrontendIsSplit(Frontend))
-            TransmitterNotify(FrontendGetTransmitter(Frontend),
-                              Ring->Index);
-    }
+    __ReceiverRingAcquireLock(Ring);
+
+    if (Ring->Enabled)
+        ReceiverRingPoll(Ring);
 
+    __ReceiverRingReleaseLock(Ring);
     __ReceiverRingUnmask(Ring);
 }
 
@@ -2054,6 +2040,8 @@ ReceiverRingEvtchnCallback(
     )
 {
     PXENVIF_RECEIVER_RING       Ring = Argument;
+    PXENVIF_RECEIVER            Receiver;
+    PXENVIF_FRONTEND            Frontend;
 
     UNREFERENCED_PARAMETER(InterruptObject);
 
@@ -2061,8 +2049,14 @@ ReceiverRingEvtchnCallback(
 
     Ring->Events++;
 
-    if (KeInsertQueueDpc(&Ring->Dpc, NULL, NULL))
-        Ring->Dpcs++;
+    (VOID) KeInsertQueueDpc(&Ring->Dpc, NULL, NULL);
+
+    Receiver = Ring->Receiver;
+    Frontend = Receiver->Frontend;
+
+    if (!FrontendIsSplit(Frontend))
+        TransmitterNotify(FrontendGetTransmitter(Frontend),
+                          Ring->Index);
 
     return TRUE;
 }
@@ -2529,8 +2523,7 @@ __ReceiverRingEnable(
 
     Ring->Enabled = TRUE;
 
-    if (KeInsertQueueDpc(&Ring->Dpc, NULL, NULL))
-        Ring->Dpcs++;
+    (VOID) KeInsertQueueDpc(&Ring->Dpc, NULL, NULL);
 
     __ReceiverRingReleaseLock(Ring);
 
@@ -2581,6 +2574,7 @@ __ReceiverRingDisconnect(
     Ring->Channel = NULL;
 
     Ring->Events = 0;
+    Ring->Dpcs = 0;
 
     ASSERT3U(Ring->ResponsesProcessed, ==, Ring->RequestsPushed);
     ASSERT3U(Ring->RequestsPushed, ==, Ring->RequestsPosted);
@@ -2635,7 +2629,6 @@ __ReceiverRingTeardown(
     Receiver = Ring->Receiver;
     Frontend = Receiver->Frontend;
 
-    Ring->Dpcs = 0;
     RtlZeroMemory(&Ring->Dpc, sizeof (KDPC));
 
     Ring->BackfillSize = 0;

diff --git a/src/xenvif/transmitter.c b/src/xenvif/transmitter.c
index f6766ce722514b4a7cb3cba12c20c78f61bf7eee..fdb13348351a91830ff16d699d4df13095c09068 100644 (file)
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -2912,16 +2912,6 @@ TransmitterRingReleaseLock(
     __TransmitterRingReleaseLock(Ring);
 }
 
-static FORCEINLINE VOID
-__TransmitterRingNotify(
-    IN  PXENVIF_TRANSMITTER_RING    Ring
-    )
-{
-    __TransmitterRingAcquireLock(Ring);
-    TransmitterRingPoll(Ring);
-    __TransmitterRingReleaseLock(Ring);
-}
-
 static FORCEINLINE VOID
 __TransmitterRingUnmask(
     IN  PXENVIF_TRANSMITTER_RING    Ring
@@ -2954,7 +2944,6 @@ TransmitterRingDpc(
     )
 {
     PXENVIF_TRANSMITTER_RING    Ring = Context;
-    PXENVIF_TRANSMITTER         Transmitter;
 
     UNREFERENCED_PARAMETER(Dpc);
     UNREFERENCED_PARAMETER(Argument1);
@@ -2962,11 +2951,14 @@ TransmitterRingDpc(
 
     ASSERT(Ring != NULL);
 
-    Transmitter = Ring->Transmitter;
+    Ring->Dpcs++;
+
+    __TransmitterRingAcquireLock(Ring);
 
     if (Ring->Enabled)
-        __TransmitterRingNotify(Ring);
+        TransmitterRingPoll(Ring);
 
+    __TransmitterRingReleaseLock(Ring);
     __TransmitterRingUnmask(Ring);
 }
 
@@ -2980,17 +2972,20 @@ TransmitterRingEvtchnCallback(
 {
     PXENVIF_TRANSMITTER_RING    Ring = Argument;
     PXENVIF_TRANSMITTER         Transmitter;
+    PXENVIF_FRONTEND            Frontend;
 
     UNREFERENCED_PARAMETER(InterruptObject);
 
     ASSERT(Ring != NULL);
 
     Transmitter = Ring->Transmitter;
+    Frontend = Transmitter->Frontend;
+
+    ASSERT(FrontendIsSplit(Frontend));
 
     Ring->Events++;
 
-    if (KeInsertQueueDpc(&Ring->Dpc, NULL, NULL))
-        Ring->Dpcs++;
+    (VOID) KeInsertQueueDpc(&Ring->Dpc, NULL, NULL);
 
     return TRUE;
 }
@@ -3565,9 +3560,8 @@ __TransmitterRingEnable(
     ASSERT(!Ring->Enabled);
     Ring->Enabled = TRUE;
 
-    if (FrontendIsSplit(Frontend) &&
-        KeInsertQueueDpc(&Ring->Dpc, NULL, NULL))
-        Ring->Dpcs++;
+    if (FrontendIsSplit(Frontend))
+        KeInsertQueueDpc(&Ring->Dpc, NULL, NULL);
 
     __TransmitterRingReleaseLock(Ring);
 
@@ -3681,6 +3675,8 @@ __TransmitterRingDisconnect(
         Ring->Events = 0;
     }
 
+    Ring->Dpcs = 0;
+
     ASSERT3U(Ring->ResponsesProcessed, ==, Ring->RequestsPushed);
     ASSERT3U(Ring->RequestsPushed, ==, Ring->RequestsPosted);
 
@@ -3755,7 +3751,6 @@ __TransmitterRingTeardown(
     Transmitter = Ring->Transmitter;
     Frontend = Transmitter->Frontend;
 
-    Ring->Dpcs = 0;
     RtlZeroMemory(&Ring->Dpc, sizeof (KDPC));
 
     ASSERT3U(Ring->PacketsCompleted, ==, Ring->PacketsSent);
@@ -4568,16 +4563,18 @@ __TransmitterHashPacket(
     PIP_HEADER                      IpHeader;
     ULONG                           Value;
 
-    Value = 0;
-
     StartVa = Packet->Header;
     Info = &Packet->Info;
 
-    if (Info->IpHeader.Length == 0)
+    if (Info->IpHeader.Length == 0) {
+        Value = KeGetCurrentProcessorNumberEx(NULL);
         goto done;
+    }
 
     IpHeader = (PIP_HEADER)(StartVa + Info->IpHeader.Offset);
 
+    Value = 0;
+
     if (IpHeader->Version == 4) {
         PIPV4_HEADER    Version4 = &IpHeader->Version4;
 
@@ -4781,11 +4778,16 @@ TransmitterNotify(
     IN  ULONG                   Index
     )
 {
+    PXENVIF_FRONTEND            Frontend;
     PXENVIF_TRANSMITTER_RING    Ring;
 
+    Frontend = Transmitter->Frontend;
+
+    ASSERT(!FrontendIsSplit(Frontend));
+
     Ring = Transmitter->Ring[Index];
 
-    __TransmitterRingNotify(Ring);
+    (VOID) KeInsertQueueDpc(&Ring->Dpc, NULL, NULL);
 }
 
 VOID