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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [win-pv-devel] [PATCH for 8.2] Remove unnecessary complexity from the controller frontend
The controller ring is driven much like the store ring in XENBUS for
request/response but, unlike the store ring, there are no asynchronous
events (like watches) so we really don't need a DPC and an asynchronous
poll, or a watchdog.
This patch removes that code, and also shortens the poll timeout when
waiting for a response since use of XENBUS_EVTCHN(...Wait...) is
inherently racey.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
src/xenvif/controller.c | 152 +++---------------------------------------------
1 file changed, 7 insertions(+), 145 deletions(-)
diff --git a/src/xenvif/controller.c b/src/xenvif/controller.c
index 6414819..243295f 100644
--- a/src/xenvif/controller.c
+++ b/src/xenvif/controller.c
@@ -69,8 +69,6 @@ struct _XENVIF_CONTROLLER {
xen_netif_ctrl_sring_t *Shared;
PXENBUS_GNTTAB_ENTRY Entry;
PXENBUS_EVTCHN_CHANNEL Channel;
- KDPC Dpc;
- ULONG Dpcs;
ULONG Events;
BOOLEAN Connected;
USHORT RequestId;
@@ -81,7 +79,6 @@ struct _XENVIF_CONTROLLER {
XENBUS_STORE_INTERFACE StoreInterface;
XENBUS_DEBUG_INTERFACE DebugInterface;
PXENBUS_DEBUG_CALLBACK DebugCallback;
- PXENVIF_THREAD WatchdogThread;
};
#define XENVIF_CONTROLLER_TAG 'TNOC'
@@ -202,7 +199,11 @@ ControllerPutRequest(
goto fail2;
Controller->Request.type = Type;
+
Controller->Request.id = Controller->RequestId++;
+ if (Controller->Request.id == 0) // Make sure we skip zero
+ Controller->Request.id = Controller->RequestId++;
+
Controller->Request.data[0] = Data0;
Controller->Request.data[1] = Data1;
Controller->Request.data[2] = Data2;
@@ -242,10 +243,9 @@ fail1:
#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_CONTROLLER_POLL_PERIOD 5
+#define XENVIF_CONTROLLER_POLL_PERIOD 100 // ms
static NTSTATUS
ControllerGetResponse(
@@ -256,7 +256,7 @@ ControllerGetResponse(
LARGE_INTEGER Timeout;
NTSTATUS status;
- Timeout.QuadPart = TIME_RELATIVE(TIME_S(XENVIF_CONTROLLER_POLL_PERIOD));
+ Timeout.QuadPart = TIME_RELATIVE(TIME_MS(XENVIF_CONTROLLER_POLL_PERIOD));
for (;;) {
ControllerPoll(Controller);
@@ -270,7 +270,7 @@ ControllerGetResponse(
Controller->Channel,
&Timeout);
if (status == STATUS_TIMEOUT)
- Warning("TIMED OUT\n");
+ __ControllerSend(Controller);
}
ASSERT3U(Controller->Response.type, ==, Controller->Request.type);
@@ -308,103 +308,6 @@ ControllerGetResponse(
return status;
}
-#define XENVIF_CONTROLLER_WATCHDOG_PERIOD 15
-
-static NTSTATUS
-ControllerWatchdog(
- IN PXENVIF_THREAD Self,
- IN PVOID Context
- )
-{
- PXENVIF_CONTROLLER Controller = Context;
- LARGE_INTEGER Timeout;
- RING_IDX rsp_prod;
- RING_IDX rsp_cons;
-
- Trace("====>\n");
-
- Timeout.QuadPart =
TIME_RELATIVE(TIME_S(XENVIF_CONTROLLER_WATCHDOG_PERIOD));
-
- rsp_prod = 0;
- rsp_cons = 0;
-
- for (;;) {
- PKEVENT Event;
- KIRQL Irql;
-
- Event = ThreadGetEvent(Self);
-
- (VOID) KeWaitForSingleObject(Event,
- Executive,
- KernelMode,
- FALSE,
- &Timeout);
- KeClearEvent(Event);
-
- if (ThreadIsAlerted(Self))
- break;
-
- KeRaiseIrql(DISPATCH_LEVEL, &Irql);
- __ControllerAcquireLock(Controller);
-
- if (Controller->Connected) {
- KeMemoryBarrier();
-
- if (Controller->Shared->rsp_prod != rsp_prod &&
- Controller->Front.rsp_cons == rsp_cons) {
- XENBUS_DEBUG(Trigger,
- &Controller->DebugInterface,
- Controller->DebugCallback);
-
- // Try to move things along
- ControllerPoll(Controller);
- __ControllerSend(Controller);
- }
-
- KeMemoryBarrier();
-
- rsp_prod = Controller->Shared->rsp_prod;
- rsp_cons = Controller->Front.rsp_cons;
- }
-
- __ControllerReleaseLock(Controller);
- KeLowerIrql(Irql);
- }
-
- Trace("<====\n");
-
- return STATUS_SUCCESS;
-}
-
-__drv_functionClass(KDEFERRED_ROUTINE)
-__drv_maxIRQL(DISPATCH_LEVEL)
-__drv_minIRQL(DISPATCH_LEVEL)
-__drv_requiresIRQL(DISPATCH_LEVEL)
-__drv_sameIRQL
-static VOID
-ControllerDpc(
- IN PKDPC Dpc,
- IN PVOID Context,
- IN PVOID Argument1,
- IN PVOID Argument2
- )
-{
- PXENVIF_CONTROLLER Controller = Context;
-
- UNREFERENCED_PARAMETER(Dpc);
- UNREFERENCED_PARAMETER(Argument1);
- UNREFERENCED_PARAMETER(Argument2);
-
- ASSERT(Controller != NULL);
-
- __ControllerAcquireLock(Controller);
-
- if (Controller->Connected)
- ControllerPoll(Controller);
-
- __ControllerReleaseLock(Controller);
-}
-
KSERVICE_ROUTINE ControllerEvtchnCallback;
BOOLEAN
@@ -421,9 +324,6 @@ ControllerEvtchnCallback(
Controller->Events++;
- if (KeInsertQueueDpc(&Controller->Dpc, NULL, NULL))
- Controller->Dpcs++;
-
return TRUE;
}
@@ -466,41 +366,16 @@ ControllerInitialize(
&(*Controller)->EvtchnInterface);
KeInitializeSpinLock(&(*Controller)->Lock);
- KeInitializeDpc(&(*Controller)->Dpc, ControllerDpc, *Controller);
KeQuerySystemTime(&Now);
Seed = Now.LowPart;
(*Controller)->RequestId = (USHORT)RtlRandomEx(&Seed);
- status = ThreadCreate(ControllerWatchdog,
- *Controller,
- &(*Controller)->WatchdogThread);
- if (!NT_SUCCESS(status))
- goto fail2;
-
(*Controller)->Frontend = Frontend;
return STATUS_SUCCESS;
-fail2:
- Error("fail2\n");
-
- RtlZeroMemory(&(*Controller)->Lock,
- sizeof (KSPIN_LOCK));
-
- RtlZeroMemory(&(*Controller)->GnttabInterface,
- sizeof (XENBUS_GNTTAB_INTERFACE));
-
- RtlZeroMemory(&(*Controller)->StoreInterface,
- sizeof (XENBUS_STORE_INTERFACE));
-
- RtlZeroMemory(&(*Controller)->DebugInterface,
- sizeof (XENBUS_DEBUG_INTERFACE));
-
- RtlZeroMemory(&(*Controller)->EvtchnInterface,
- sizeof (XENBUS_EVTCHN_INTERFACE));
-
fail1:
Error("fail1 (%08x)\n", status);
@@ -638,9 +513,6 @@ ControllerConnect(
Controller->Connected = TRUE;
- if (KeInsertQueueDpc(&Controller->Dpc, NULL, NULL))
- Controller->Dpcs++;
-
__ControllerReleaseLock(Controller);
done:
@@ -656,7 +528,6 @@ fail10:
Controller->Channel = NULL;
Controller->Events = 0;
- Controller->Dpcs = 0;
fail9:
Error("fail9\n");
@@ -818,7 +689,6 @@ ControllerDisconnect(
Controller->Channel = NULL;
Controller->Events = 0;
- Controller->Dpcs = 0;
(VOID) XENBUS_GNTTAB(RevokeForeignAccess,
&Controller->GnttabInterface,
@@ -858,19 +728,11 @@ ControllerTeardown(
)
{
ASSERT3U(KeGetCurrentIrql(), ==, PASSIVE_LEVEL);
- KeFlushQueuedDpcs();
Controller->Frontend = NULL;
- ThreadAlert(Controller->WatchdogThread);
- ThreadJoin(Controller->WatchdogThread);
- Controller->WatchdogThread = NULL;
-
Controller->RequestId = 0;
- RtlZeroMemory(&Controller->Dpc,
- sizeof (KDPC));
-
RtlZeroMemory(&Controller->Lock,
sizeof (KSPIN_LOCK));
--
2.5.3
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