[win-pv-devel] [PATCH 1/3] Fix DPC accounting

[Paul Durrant <pdurrant@xxxxxxxxx>]

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@xxxxxxxxxx>
---
 src/xenvif/receiver.c    | 43 ++++++++++++++++++-------------------------
 src/xenvif/transmitter.c | 48 +++++++++++++++++++++++++-----------------------
 2 files changed, 43 insertions(+), 48 deletions(-)

diff --git a/src/xenvif/receiver.c b/src/xenvif/receiver.c
index 62ca1c8..29877f2 100644
--- a/src/xenvif/receiver.c
+++ b/src/xenvif/receiver.c
@@ -1982,16 +1982,6 @@ ReceiverRingPoll(
 }
 
 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 f6766ce..fdb1334 100644
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -2913,16 +2913,6 @@ TransmitterRingReleaseLock(
 }
 
 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
-- 
2.1.1


_______________________________________________
win-pv-devel mailing list
win-pv-devel@xxxxxxxxxxxxxxxxxxxx
http://lists.xenproject.org/cgi-bin/mailman/listinfo/win-pv-devel