Remove KTIMERS from transmit and receive paths (again)

Even though the poller subsystem has been reverted, these still need to
go away as they do not adequately serve the purpose for which they were
added: DPC watchdog avoidance.

A subsequent patch will re-instate the threaded DPC in the receiver to
avoid the DPC watchdog.

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

diff --git a/src/xenvif/receiver.c b/src/xenvif/receiver.c
index 3ed5ee88052e6764315da0955bcd92adffb390b7..63f0e0eac34a243afd3f6c6f23b854d04d2b00ce 100644 (file)
--- a/src/xenvif/receiver.c
+++ b/src/xenvif/receiver.c
@@ -91,8 +91,6 @@ typedef struct _XENVIF_RECEIVER_RING {
     PXENBUS_EVTCHN_CHANNEL      Channel;
     KDPC                        Dpc;
     ULONG                       Dpcs;
-    KTIMER                      Timer;
-    KDPC                        TimerDpc;
     ULONG                       Events;
     PXENVIF_RECEIVER_FRAGMENT   Pending[XENVIF_RECEIVER_MAXIMUM_FRAGMENT_ID + 1];
     ULONG                       RequestsPosted;
@@ -2211,37 +2209,6 @@ __ReceiverRingUnmask(
                   TRUE);
 }
 
-static FORCEINLINE BOOLEAN
-__ReceiverRingDpcTimeout(
-    IN  PXENVIF_RECEIVER_RING   Ring
-    )
-{
-    KDPC_WATCHDOG_INFORMATION   Watchdog;
-    NTSTATUS                    status;
-
-    UNREFERENCED_PARAMETER(Ring);
-
-    RtlZeroMemory(&Watchdog, sizeof (Watchdog));
-
-    status = KeQueryDpcWatchdogInformation(&Watchdog);
-    ASSERT(NT_SUCCESS(status));
-
-    if (Watchdog.DpcTimeLimit == 0 ||
-        Watchdog.DpcWatchdogLimit == 0)
-        return FALSE;
-
-    if (Watchdog.DpcTimeCount > (Watchdog.DpcTimeLimit / 2) &&
-        Watchdog.DpcWatchdogCount > (Watchdog.DpcWatchdogLimit / 2))
-        return FALSE;
-
-    return TRUE;
-}
-
-#define TIME_US(_us)        ((_us) * 10)
-#define TIME_MS(_ms)        (TIME_US((_ms) * 1000))
-#define TIME_S(_s)          (TIME_MS((_s) * 1000))
-#define TIME_RELATIVE(_t)   (-(_t))
-
 __drv_functionClass(KDEFERRED_ROUTINE)
 __drv_maxIRQL(DISPATCH_LEVEL)
 __drv_minIRQL(DISPATCH_LEVEL)
@@ -2274,15 +2241,6 @@ ReceiverRingDpc(
             __ReceiverRingUnmask(Ring);
             break;
         }
-
-        if (__ReceiverRingDpcTimeout(Ring)) {
-            LARGE_INTEGER   Delay;
-
-            Delay.QuadPart = TIME_RELATIVE(TIME_US(100));
-
-            KeSetTimer(&Ring->Timer, Delay, &Ring->TimerDpc);
-            break;
-        }
     }
 }
 
@@ -2317,6 +2275,11 @@ ReceiverRingEvtchnCallback(
     return TRUE;
 }
 
+#define TIME_US(_us)        ((_us) * 10)
+#define TIME_MS(_ms)        (TIME_US((_ms) * 1000))
+#define TIME_S(_s)          (TIME_MS((_s) * 1000))
+#define TIME_RELATIVE(_t)   (-(_t))
+
 #define XENVIF_RECEIVER_WATCHDOG_PERIOD 30
 
 static NTSTATUS
@@ -2438,8 +2401,6 @@ __ReceiverRingInitialize(
     InitializeListHead(&(*Ring)->PacketList);
 
     KeInitializeDpc(&(*Ring)->Dpc, ReceiverRingDpc, *Ring);
-    KeInitializeTimer(&(*Ring)->Timer);
-    KeInitializeDpc(&(*Ring)->TimerDpc, ReceiverRingDpc, *Ring);
 
     status = RtlStringCbPrintfA(Name,
                                 sizeof (Name),
@@ -2524,8 +2485,6 @@ fail4:
 fail3:
     Error("fail3\n");
 
-    RtlZeroMemory(&(*Ring)->TimerDpc, sizeof (KDPC));
-    RtlZeroMemory(&(*Ring)->Timer, sizeof (KTIMER));
     RtlZeroMemory(&(*Ring)->Dpc, sizeof (KDPC));
 
     RtlZeroMemory(&(*Ring)->PacketList, sizeof (LIST_ENTRY));
@@ -2641,7 +2600,6 @@ __ReceiverRingConnect(
     ASSERT(NT_SUCCESS(status));
 
     KeSetTargetProcessorDpcEx(&Ring->Dpc, &ProcNumber);
-    KeSetTargetProcessorDpcEx(&Ring->TimerDpc, &ProcNumber);
 
     (VOID) XENBUS_EVTCHN(Bind,
                          &Receiver->EvtchnInterface,
@@ -2846,12 +2804,6 @@ __ReceiverRingDisable(
 
     __ReceiverRingReleaseLock(Ring);
 
-    //
-    // No new timers can be scheduled once Enabled goes to FALSE.
-    // Cancel any existing ones.
-    //
-    (VOID) KeCancelTimer(&Ring->Timer);
-
     Info("%s[%u]: <====\n",
          FrontendGetPath(Frontend),
          Ring->Index);
@@ -2925,8 +2877,6 @@ __ReceiverRingTeardown(
     Frontend = Receiver->Frontend;
 
     RtlZeroMemory(&Ring->Hash, sizeof (XENVIF_RECEIVER_HASH));
-    RtlZeroMemory(&Ring->TimerDpc, sizeof (KDPC));
-    RtlZeroMemory(&Ring->Timer, sizeof (KTIMER));
     RtlZeroMemory(&Ring->Dpc, sizeof (KDPC));
 
     Ring->BackfillSize = 0;

diff --git a/src/xenvif/transmitter.c b/src/xenvif/transmitter.c
index 770aca9e1659b8e65fb2873068a049ff97f9787e..02c0d3e5cebc95990d9d68790fd341433acf9830 100644 (file)
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -182,8 +182,6 @@ typedef struct _XENVIF_TRANSMITTER_RING {
     PXENBUS_EVTCHN_CHANNEL          Channel;
     KDPC                            Dpc;
     ULONG                           Dpcs;
-    KTIMER                          Timer;
-    KDPC                            TimerDpc;
     ULONG                           Events;
     BOOLEAN                         Connected;
     BOOLEAN                         Enabled;
@@ -3250,37 +3248,6 @@ __TransmitterRingUnmask(
                   TRUE);
 }
 
-static FORCEINLINE BOOLEAN
-__TransmitterRingDpcTimeout(
-    IN  PXENVIF_TRANSMITTER_RING    Ring
-    )
-{
-    KDPC_WATCHDOG_INFORMATION       Watchdog;
-    NTSTATUS                        status;
-
-    UNREFERENCED_PARAMETER(Ring);
-
-    RtlZeroMemory(&Watchdog, sizeof (Watchdog));
-
-    status = KeQueryDpcWatchdogInformation(&Watchdog);
-    ASSERT(NT_SUCCESS(status));
-
-    if (Watchdog.DpcTimeLimit == 0 ||
-        Watchdog.DpcWatchdogLimit == 0)
-        return FALSE;
-
-    if (Watchdog.DpcTimeCount > (Watchdog.DpcTimeLimit / 2) &&
-        Watchdog.DpcWatchdogCount > (Watchdog.DpcWatchdogLimit / 2))
-        return FALSE;
-
-    return TRUE;
-}
-
-#define TIME_US(_us)        ((_us) * 10)
-#define TIME_MS(_ms)        (TIME_US((_ms) * 1000))
-#define TIME_S(_s)          (TIME_MS((_s) * 1000))
-#define TIME_RELATIVE(_t)   (-(_t))
-
 __drv_functionClass(KDEFERRED_ROUTINE)
 __drv_maxIRQL(DISPATCH_LEVEL)
 __drv_minIRQL(DISPATCH_LEVEL)
@@ -3313,15 +3280,6 @@ TransmitterRingDpc(
             __TransmitterRingUnmask(Ring);
             break;
         }
-
-        if (__TransmitterRingDpcTimeout(Ring)) {
-            LARGE_INTEGER   Delay;
-
-            Delay.QuadPart = TIME_RELATIVE(TIME_US(100));
-
-            KeSetTimer(&Ring->Timer, Delay, &Ring->TimerDpc);
-            break;
-        }
     }
 }
 
@@ -3354,6 +3312,11 @@ TransmitterRingEvtchnCallback(
     return TRUE;
 }
 
+#define TIME_US(_us)        ((_us) * 10)
+#define TIME_MS(_ms)        (TIME_US((_ms) * 1000))
+#define TIME_S(_s)          (TIME_MS((_s) * 1000))
+#define TIME_RELATIVE(_t)   (-(_t))
+
 #define XENVIF_TRANSMITTER_WATCHDOG_PERIOD  30
 
 static NTSTATUS
@@ -3467,8 +3430,6 @@ __TransmitterRingInitialize(
     InitializeListHead(&(*Ring)->PacketComplete);
 
     KeInitializeDpc(&(*Ring)->Dpc, TransmitterRingDpc, *Ring);
-    KeInitializeTimer(&(*Ring)->Timer);
-    KeInitializeDpc(&(*Ring)->TimerDpc, TransmitterRingDpc, *Ring);
 
     status = RtlStringCbPrintfA(Name,
                                 sizeof (Name),
@@ -3789,7 +3750,6 @@ __TransmitterRingConnect(
         ASSERT(NT_SUCCESS(status));
 
         KeSetTargetProcessorDpcEx(&Ring->Dpc, &ProcNumber);
-        KeSetTargetProcessorDpcEx(&Ring->TimerDpc, &ProcNumber);
 
         (VOID) XENBUS_EVTCHN(Bind,
                              &Transmitter->EvtchnInterface,
@@ -4046,12 +4006,6 @@ __TransmitterRingDisable(
 
     __TransmitterRingReleaseLock(Ring);
 
-    //
-    // No new timers can be scheduled once Enabled goes to FALSE.
-    // Cancel any existing ones.
-    //
-    (VOID) KeCancelTimer(&Ring->Timer);
-
     Info("%s[%u]: <====\n",
          FrontendGetPath(Frontend),
          Ring->Index);
@@ -4127,8 +4081,6 @@ __TransmitterRingTeardown(
 
     Ring->Dpcs = 0;
 
-    RtlZeroMemory(&Ring->TimerDpc, sizeof (KDPC));
-    RtlZeroMemory(&Ring->Timer, sizeof (KTIMER));
     RtlZeroMemory(&Ring->Dpc, sizeof (KDPC));
 
     ASSERT3U(Ring->PacketsCompleted, ==, Ring->PacketsSent);