dpc.c File Reference

#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for dpc.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
VOID NTAPI	KiCheckTimerTable (IN ULARGE_INTEGER CurrentTime)
VOID NTAPI	KiTimerExpiration (IN PKDPC Dpc, IN PVOID DeferredContext, IN PVOID SystemArgument1, IN PVOID SystemArgument2)
VOID FASTCALL	KiTimerListExpire (IN PLIST_ENTRY ExpiredListHead, IN KIRQL OldIrql)
	_Requires_lock_not_held_ (Prcb->PrcbLock) VOID NTAPI KiQuantumEnd(VOID)
VOID FASTCALL	KiRetireDpcList (IN PKPRCB Prcb)
VOID NTAPI	KiInitializeDpc (IN PKDPC Dpc, IN PKDEFERRED_ROUTINE DeferredRoutine, IN PVOID DeferredContext, IN KOBJECTS Type)
VOID NTAPI	KeInitializeThreadedDpc (IN PKDPC Dpc, IN PKDEFERRED_ROUTINE DeferredRoutine, IN PVOID DeferredContext)
VOID NTAPI	KeInitializeDpc (IN PKDPC Dpc, IN PKDEFERRED_ROUTINE DeferredRoutine, IN PVOID DeferredContext)
BOOLEAN NTAPI	KeInsertQueueDpc (IN PKDPC Dpc, IN PVOID SystemArgument1, IN PVOID SystemArgument2)
BOOLEAN NTAPI	KeRemoveQueueDpc (IN PKDPC Dpc)
VOID NTAPI	KeFlushQueuedDpcs (VOID)
BOOLEAN NTAPI	KeIsExecutingDpc (VOID)
VOID NTAPI	KeSetImportanceDpc (IN PKDPC Dpc, IN KDPC_IMPORTANCE Importance)
VOID NTAPI	KeSetTargetProcessorDpc (IN PKDPC Dpc, IN CCHAR Number)
VOID NTAPI	KeGenericCallDpc (IN PKDEFERRED_ROUTINE Routine, IN PVOID Context)
VOID NTAPI	KeSignalCallDpcDone (IN PVOID SystemArgument1)
BOOLEAN NTAPI	KeSignalCallDpcSynchronize (IN PVOID SystemArgument2)

Variables
ULONG	KiMaximumDpcQueueDepth = 4
ULONG	KiMinimumDpcRate = 3
ULONG	KiAdjustDpcThreshold = 20
ULONG	KiIdealDpcRate = 20
BOOLEAN	KeThreadDpcEnable
FAST_MUTEX	KiGenericCallDpcMutex
KDPC	KiTimerExpireDpc
ULONG	KiTimeLimitIsrMicroseconds
ULONG	KiDPCTimeout = 110

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 14 of file dpc.c.

Function Documentation

_Requires_lock_not_held_()

_Requires_lock_not_held_

(

Prcb->

PrcbLock

)

Definition at line 463 of file dpc.c.

{
    PKPRCB Prcb = KeGetCurrentPrcb();
    PKTHREAD NextThread, Thread = Prcb->CurrentThread;

    /* Check if a DPC Event was requested to be signaled */
    if (InterlockedExchange(&Prcb->DpcSetEventRequest, 0))
    {
        /* Signal it */
        KeSetEvent(&Prcb->DpcEvent, 0, 0);
    }

    /* Raise to synchronization level and lock the PRCB and thread */
    KeRaiseIrqlToSynchLevel();
    KiAcquireThreadLock(Thread);
    KiAcquirePrcbLock(Prcb);

    /* Check if Quantum expired */
    if (Thread->Quantum <= 0)
    {
        /* Check if we're real-time and with quantums disabled */
        if ((Thread->Priority >= LOW_REALTIME_PRIORITY) &&
            (Thread->ApcState.Process->DisableQuantum))
        {
            /* Otherwise, set maximum quantum */
            Thread->Quantum = MAX_QUANTUM;
        }
        else
        {
            /* Reset the new Quantum */
            Thread->Quantum = Thread->QuantumReset;

            /* Calculate new priority */
            Thread->Priority = KiComputeNewPriority(Thread, 1);

            /* Check if a new thread is scheduled */
            if (!Prcb->NextThread)
            {
                /* Get a new ready thread */
                NextThread = KiSelectReadyThread(Thread->Priority, Prcb);
                if (NextThread)
                {
                    /* Found one, set it on standby */
                    NextThread->State = Standby;
                    Prcb->NextThread = NextThread;
                }
            }
            else
            {
                /* Otherwise, make sure that this thread doesn't get preempted */
                Thread->Preempted = FALSE;
            }
        }
    }

    /* Release the thread lock */
    KiReleaseThreadLock(Thread);

    /* Check if there's no thread scheduled */
    if (!Prcb->NextThread)
    {
        /* Just leave now */
        KiReleasePrcbLock(Prcb);
        KeLowerIrql(DISPATCH_LEVEL);
        return;
    }

    /* Get the next thread now */
    NextThread = Prcb->NextThread;

    /* Set current thread's swap busy to true */
    KiSetThreadSwapBusy(Thread);

    /* Switch threads in PRCB */
    Prcb->NextThread = NULL;
    Prcb->CurrentThread = NextThread;

    /* Set thread to running and the switch reason to Quantum End */
    NextThread->State = Running;
    Thread->WaitReason = WrQuantumEnd;

    /* Queue it on the ready lists */
    KxQueueReadyThread(Thread, Prcb);

    /* Set wait IRQL to APC_LEVEL */
    Thread->WaitIrql = APC_LEVEL;

    /* Swap threads */
    KiSwapContext(APC_LEVEL, Thread);

    /* Lower IRQL back to DISPATCH_LEVEL */
    KeLowerIrql(DISPATCH_LEVEL);
}

KeFlushQueuedDpcs()

VOID NTAPI KeFlushQueuedDpcs

(

VOID

)

Definition at line 919 of file dpc.c.

{
    PKPRCB CurrentPrcb = KeGetCurrentPrcb();
    PAGED_CODE();

    /* Check if this is an UP machine */
    if (KeActiveProcessors == 1)
    {
        /* Check if there are DPCs on either queues */
        if ((CurrentPrcb->DpcData[DPC_NORMAL].DpcQueueDepth > 0) ||
            (CurrentPrcb->DpcData[DPC_THREADED].DpcQueueDepth > 0))
        {
            /* Request an interrupt */
            HalRequestSoftwareInterrupt(DISPATCH_LEVEL);
        }
    }
    else
    {
        /* FIXME: SMP support required */
        ASSERT(FALSE);
    }
}

Referenced by FxDpc::Cancel(), DeviceEvtSelfManagedIoCleanup(), FxUsbDevice::Dispose(), ExpDeleteTimer(), FxDpc::FlushAndRundown(), FxInterrupt::FlushQueuedDpcs(), InPortRemoveDevice(), MmPageEntireDriver(), and Mx::MxFlushQueuedDpcs().

KeGenericCallDpc()

VOID NTAPI KeGenericCallDpc	(	IN PKDEFERRED_ROUTINE	Routine,
		IN PVOID	Context
	)

Definition at line 984 of file dpc.c.

{
    ULONG Barrier = KeNumberProcessors;
    KIRQL OldIrql;
    DEFERRED_REVERSE_BARRIER ReverseBarrier;
    ASSERT(KeGetCurrentIrql () < DISPATCH_LEVEL);

    //
    // The barrier is the number of processors, each processor will decrement it
    // by one, so when all processors have run the DPC, the barrier reaches zero
    //
    ReverseBarrier.Barrier = Barrier;
    ReverseBarrier.TotalProcessors = Barrier;

    //
    // But we don't need the barrier on UP, since we can simply call the routine
    // directly while at DISPATCH_LEVEL and not worry about anything else
    //
    KeRaiseIrql(DISPATCH_LEVEL, &OldIrql);
    Routine(&KeGetCurrentPrcb()->CallDpc, Context, &Barrier, &ReverseBarrier);
    KeLowerIrql(OldIrql);
}

Referenced by ExGetPoolTagInfo().

KeInitializeDpc()

VOID NTAPI KeInitializeDpc	(	IN PKDPC	Dpc,
		IN PKDEFERRED_ROUTINE	DeferredRoutine,
		IN PVOID	DeferredContext
	)

Definition at line 712 of file dpc.c.

{
    /* Call the internal routine */
    KiInitializeDpc(Dpc, DeferredRoutine, DeferredContext, DpcObject);
}

Referenced by _Requires_lock_held_(), acpi_bus_init(), AddControllers(), AfdSelect(), CcInitializeCacheManager(), ClasspInitializeIdleTimer(), ClasspInitializeTimer(), ClassPnpStartDevice(), CmpCmdInit(), CmpInitDelayDerefKCBEngine(), CmpInitializeDelayedCloseTable(), FxUsbPipeContinuousReader::Config(), CServiceGroup::CServiceGroup(), CTEInitTimer(), DispEchoRequest(), DriverEntry(), Ext2StartFloppyFlushDpc(), FreeBT_AddDevice(), FxInterrupt::FxInterrupt(), FxIoQueue::FxIoQueue(), i8042KbdInternalDeviceControl(), i8042MouInternalDeviceControl(), InitController(), MxTimer::Initialize(), FxDpc::Initialize(), InitializeDeviceData(), InitPiceRunningTimer(), IntVideoPortCreateAdapterDeviceObject(), IoInitializeDpcRequest(), IoInitSystem(), IopRestartLogWorker(), KdInitSystem(), KeBalanceSetManager(), KeyboardDeviceWorker(), KiInitializeKernel(), KiInitSpinLocks(), KiInitSystem(), KsCreateBusEnumObject(), MsfsRead(), NdisIAddDevice(), NdisInitializeTimer(), NdisMInitializeTimer(), NdisMRegisterInterrupt(), NpAddWaiter(), NtCreateTimer(), PoInitializePrcb(), RxInitializeRxTimer(), ScratchBuffer_ReadWriteCompletionRoutine(), ScsiPortInitialize(), SerialAddDeviceInternal(), START_TEST(), StorPortNotification(), StreamClassAddDevice(), TCPAllocateConnectionEndpoint(), TransferPacketQueueRetryDpc(), USBH_SyncSubmitUrb(), USBPORT_RequestAsyncCallback(), USBPORT_SoftInterrupt(), USBPORT_StartDevice(), and USBPORT_StartTimer().

KeInitializeThreadedDpc()

VOID NTAPI KeInitializeThreadedDpc	(	IN PKDPC	Dpc,
		IN PKDEFERRED_ROUTINE	DeferredRoutine,
		IN PVOID	DeferredContext
	)

Definition at line 699 of file dpc.c.

{
    /* Call the internal routine */
    KiInitializeDpc(Dpc, DeferredRoutine, DeferredContext, ThreadedDpcObject);
}

Referenced by IoInitializeThreadedDpcRequest().

KeInsertQueueDpc()

BOOLEAN NTAPI KeInsertQueueDpc	(	IN PKDPC	Dpc,
		IN PVOID	SystemArgument1,
		IN PVOID	SystemArgument2
	)

Definition at line 725 of file dpc.c.

{
    KIRQL OldIrql;
    PKPRCB Prcb, CurrentPrcb;
    ULONG Cpu;
    PKDPC_DATA DpcData;
    BOOLEAN DpcConfigured = FALSE, DpcInserted = FALSE;
    ASSERT_DPC(Dpc);

    /* Check IRQL and Raise it to HIGH_LEVEL */
    KeRaiseIrql(HIGH_LEVEL, &OldIrql);
    CurrentPrcb = KeGetCurrentPrcb();

    /* Check if the DPC has more then the maximum number of CPUs */
    if (Dpc->Number >= MAXIMUM_PROCESSORS)
    {
        /* Then substract the maximum and get that PRCB. */
        Cpu = Dpc->Number - MAXIMUM_PROCESSORS;
        Prcb = KiProcessorBlock[Cpu];
    }
    else
    {
        /* Use the current one */
        Prcb = CurrentPrcb;
        Cpu = Prcb->Number;
    }

    /* ROS Sanity Check */
    ASSERT(Prcb == CurrentPrcb);

    /* Check if this is a threaded DPC and threaded DPCs are enabled */
    if ((Dpc->Type == ThreadedDpcObject) && (Prcb->ThreadDpcEnable))
    {
        /* Then use the threaded data */
        DpcData = &Prcb->DpcData[DPC_THREADED];
    }
    else
    {
        /* Otherwise, use the regular data */
        DpcData = &Prcb->DpcData[DPC_NORMAL];
    }

    /* Acquire the DPC lock */
    KiAcquireSpinLock(&DpcData->DpcLock);

    /* Get the DPC Data */
    if (!InterlockedCompareExchangePointer(&Dpc->DpcData, DpcData, NULL))
    {
        /* Now we can play with the DPC safely */
        Dpc->SystemArgument1 = SystemArgument1;
        Dpc->SystemArgument2 = SystemArgument2;
        DpcData->DpcQueueDepth++;
        DpcData->DpcCount++;
        DpcConfigured = TRUE;

        /* Check if this is a high importance DPC */
        if (Dpc->Importance == HighImportance)
        {
            /* Pre-empty other DPCs */
            InsertHeadList(&DpcData->DpcListHead, &Dpc->DpcListEntry);
        }
        else
        {
            /* Add it at the end */
            InsertTailList(&DpcData->DpcListHead, &Dpc->DpcListEntry);
        }

        /* Check if this is the DPC on the threaded list */
        if (&Prcb->DpcData[DPC_THREADED] == DpcData)
        {
            /* Make sure a threaded DPC isn't already active */
            if (!(Prcb->DpcThreadActive) && !(Prcb->DpcThreadRequested))
            {
                /* FIXME: Setup Threaded DPC */
                UNIMPLEMENTED_FATAL("Threaded DPC not supported\n");
            }
        }
        else
        {
            /* Make sure a DPC isn't executing already */
            if (!(Prcb->DpcRoutineActive) && !(Prcb->DpcInterruptRequested))
            {
                /* Check if this is the same CPU */
                if (Prcb != CurrentPrcb)
                {
                    /*
                     * Check if the DPC is of high importance or above the
                     * maximum depth. If it is, then make sure that the CPU
                     * isn't idle, or that it's sleeping.
                     */
                    if (((Dpc->Importance == HighImportance) ||
                        (DpcData->DpcQueueDepth >=
                         Prcb->MaximumDpcQueueDepth)) &&
                        (!(AFFINITY_MASK(Cpu) & KiIdleSummary) ||
                         (Prcb->Sleeping)))
                    {
                        /* Set interrupt requested */
                        Prcb->DpcInterruptRequested = TRUE;

                        /* Set DPC inserted */
                        DpcInserted = TRUE;
                    }
                }
                else
                {
                    /* Check if the DPC is of anything but low importance */
                    if ((Dpc->Importance != LowImportance) ||
                        (DpcData->DpcQueueDepth >=
                         Prcb->MaximumDpcQueueDepth) ||
                        (Prcb->DpcRequestRate < Prcb->MinimumDpcRate))
                    {
                        /* Set interrupt requested */
                        Prcb->DpcInterruptRequested = TRUE;

                        /* Set DPC inserted */
                        DpcInserted = TRUE;
                    }
                }
            }
        }
    }

    /* Release the lock */
    KiReleaseSpinLock(&DpcData->DpcLock);

    /* Check if the DPC was inserted */
    if (DpcInserted)
    {
        /* Check if this was SMP */
        if (Prcb != CurrentPrcb)
        {
            /* It was, request and IPI */
            KiIpiSend(AFFINITY_MASK(Cpu), IPI_DPC);
        }
        else
        {
            /* It wasn't, request an interrupt from HAL */
            HalRequestSoftwareInterrupt(DISPATCH_LEVEL);
        }
    }

    /* Lower IRQL */
    KeLowerIrql(OldIrql);
    return DpcConfigured;
}

Referenced by acpi_bus_generate_event(), i8042KbdInterruptService(), i8042KbdQueuePacket(), i8042MouInterruptService(), i8042MouQueuePacket(), IoRequestDpc(), Isr(), KdExitDebugger(), KeyboardDeviceWorker(), KiSignalTimer(), KiTimerExpiration(), KiTimerListExpire(), KsGenerateEvent(), Mx::MxInsertQueueDpc(), FxInterrupt::QueueDpcForIsr(), SerialInterruptService(), ServiceRoutine(), START_TEST(), StreamClassInterruptRoutine(), TransferPacketQueueRetryDpc(), USBPORT_HcQueueWakeDpc(), USBPORT_InterruptService(), USBPORT_InvalidateEndpointHandler(), USBPORT_IsrDpcHandler(), USBPORT_QueueDoneTransfer(), USBPORT_SoftInterruptDpc(), and VideoPortQueueDpc().

KeIsExecutingDpc()

BOOLEAN NTAPI KeIsExecutingDpc

(

VOID

)

Definition at line 947 of file dpc.c.

{
    /* Return if the Dpc Routine is active */
    return KeGetCurrentPrcb()->DpcRoutineActive;
}

Referenced by ExAcquireResourceExclusiveLite(), ExAcquireResourceSharedLite(), ExAcquireSharedStarveExclusive(), ExAcquireSharedWaitForExclusive(), ExConvertExclusiveToSharedLite(), ExDeleteResourceLite(), ExTryToAcquireResourceExclusiveLite(), FsRtlCopyRead(), FsRtlCopyWrite(), FsRtlMdlReadDev(), KdbpAttachToThread(), KeAttachProcess(), KeSetPriorityThread(), and KeStackAttachProcess().

KeRemoveQueueDpc()

BOOLEAN NTAPI KeRemoveQueueDpc

(

IN PKDPC

Dpc

)

Definition at line 878 of file dpc.c.

{
    PKDPC_DATA DpcData;
    BOOLEAN Enable;
    ASSERT_DPC(Dpc);

    /* Disable interrupts */
    Enable = KeDisableInterrupts();

    /* Get DPC data */
    DpcData = Dpc->DpcData;
    if (DpcData)
    {
        /* Acquire the DPC lock */
        KiAcquireSpinLock(&DpcData->DpcLock);

        /* Make sure that the data didn't change */
        if (DpcData == Dpc->DpcData)
        {
            /* Remove the DPC */
            DpcData->DpcQueueDepth--;
            RemoveEntryList(&Dpc->DpcListEntry);
            Dpc->DpcData = NULL;
        }

        /* Release the lock */
        KiReleaseSpinLock(&DpcData->DpcLock);
    }

    /* Re-enable interrupts */
    if (Enable) _enable();

    /* Return if the DPC was in the queue or not */
    return DpcData ? TRUE : FALSE;
}

Referenced by _Requires_lock_held_(), FxDpc::Cancel(), ExTimerRundown(), FatDeleteVcb(), NtCancelTimer(), NtSetTimer(), and START_TEST().

KeSetImportanceDpc()

VOID NTAPI KeSetImportanceDpc	(	IN PKDPC	Dpc,
		IN KDPC_IMPORTANCE	Importance
	)

Definition at line 958 of file dpc.c.

{
    /* Set the DPC Importance */
    ASSERT_DPC(Dpc);
    Dpc->Importance = Importance;
}

Referenced by CServiceGroup::CServiceGroup(), and KiInitSpinLocks().

KeSetTargetProcessorDpc()

VOID NTAPI KeSetTargetProcessorDpc	(	IN PKDPC	Dpc,
		IN CCHAR	Number
	)

Definition at line 971 of file dpc.c.

{
    /* Set a target CPU */
    ASSERT_DPC(Dpc);
    Dpc->Number = Number + MAXIMUM_PROCESSORS;
}

Referenced by KiInitializeKernel(), KiInitSpinLocks(), KiInitSystem(), and PoInitializePrcb().

KeSignalCallDpcDone()

VOID NTAPI KeSignalCallDpcDone

(

IN PVOID

SystemArgument1

)

Definition at line 1013 of file dpc.c.

{
    //
    // Decrement the barrier, which is actually the processor count
    //
    InterlockedDecrement((PLONG)SystemArgument1);
}

Referenced by ExpGetPoolTagInfoTarget().

KeSignalCallDpcSynchronize()

BOOLEAN NTAPI KeSignalCallDpcSynchronize

(

IN PVOID

SystemArgument2

)

Definition at line 1026 of file dpc.c.

{
    //
    // There is nothing to do on UP systems -- the processor calling this wins
    //
    UNREFERENCED_PARAMETER(SystemArgument2);
    return TRUE;
}

Referenced by ExpGetPoolTagInfoTarget().

KiCheckTimerTable()

VOID NTAPI KiCheckTimerTable

(

IN ULARGE_INTEGER

CurrentTime

)

Definition at line 33 of file dpc.c.

{
#if DBG
    ULONG i = 0;
    PLIST_ENTRY ListHead, NextEntry;
    KIRQL OldIrql;
    PKTIMER Timer;

    /* Raise IRQL to high and loop timers */
    KeRaiseIrql(HIGH_LEVEL, &OldIrql);
    do
    {
        /* Loop the current list */
        ListHead = &KiTimerTableListHead[i].Entry;
        NextEntry = ListHead->Flink;
        while (NextEntry != ListHead)
        {
            /* Get the timer and move to the next one */
            Timer = CONTAINING_RECORD(NextEntry, KTIMER, TimerListEntry);
            NextEntry = NextEntry->Flink;

            /* Check if it expired */
            if (Timer->DueTime.QuadPart <= CurrentTime.QuadPart)
            {
                /* Check if the DPC was queued, but didn't run */
                if (!(KeGetCurrentPrcb()->TimerRequest) &&
                    !(*((volatile PULONG*)(&KiTimerExpireDpc.DpcData))))
                {
                    /* This is bad, breakpoint! */
                    DPRINT1("Invalid timer state!\n");
                    DbgBreakPoint();
                }
            }
        }

        /* Move to the next timer */
        i++;
    } while(i < TIMER_TABLE_SIZE);

    /* Lower IRQL and return */
    KeLowerIrql(OldIrql);
#endif
}

Referenced by KiTimerExpiration().

KiInitializeDpc()

VOID NTAPI KiInitializeDpc	(	IN PKDPC	Dpc,
		IN PKDEFERRED_ROUTINE	DeferredRoutine,
		IN PVOID	DeferredContext,
		IN KOBJECTS	Type
	)

Definition at line 678 of file dpc.c.

{
    /* Setup the DPC Object */
    Dpc->Type = Type;
    Dpc->Number = 0;
    Dpc->Importance= MediumImportance;
    Dpc->DeferredRoutine = DeferredRoutine;
    Dpc->DeferredContext = DeferredContext;
    Dpc->DpcData = NULL;
}

Referenced by KeInitializeDpc(), and KeInitializeThreadedDpc().

KiRetireDpcList()

VOID FASTCALL KiRetireDpcList

(

IN PKPRCB

Prcb

)

Definition at line 562 of file dpc.c.

{
    PKDPC_DATA DpcData;
    PLIST_ENTRY ListHead, DpcEntry;
    PKDPC Dpc;
    PKDEFERRED_ROUTINE DeferredRoutine;
    PVOID DeferredContext, SystemArgument1, SystemArgument2;
    ULONG_PTR TimerHand;
#ifdef CONFIG_SMP
    KIRQL OldIrql;
#endif

    /* Get data and list variables before starting anything else */
    DpcData = &Prcb->DpcData[DPC_NORMAL];
    ListHead = &DpcData->DpcListHead;

    /* Main outer loop */
    do
    {
        /* Set us as active */
        Prcb->DpcRoutineActive = TRUE;

        /* Check if this is a timer expiration request */
        if (Prcb->TimerRequest)
        {
            /* It is, get the timer hand and disable timer request */
            TimerHand = Prcb->TimerHand;
            Prcb->TimerRequest = 0;

            /* Expire timers with interrups enabled */
            _enable();
            KiTimerExpiration(NULL, NULL, (PVOID)TimerHand, NULL);
            _disable();
        }

        /* Loop while we have entries in the queue */
        while (DpcData->DpcQueueDepth != 0)
        {
            /* Lock the DPC data and get the DPC entry*/
            KeAcquireSpinLockAtDpcLevel(&DpcData->DpcLock);
            DpcEntry = ListHead->Flink;

            /* Make sure we have an entry */
            if (DpcEntry != ListHead)
            {
                /* Remove the DPC from the list */
                RemoveEntryList(DpcEntry);
                Dpc = CONTAINING_RECORD(DpcEntry, KDPC, DpcListEntry);

                /* Clear its DPC data and save its parameters */
                Dpc->DpcData = NULL;
                DeferredRoutine = Dpc->DeferredRoutine;
                DeferredContext = Dpc->DeferredContext;
                SystemArgument1 = Dpc->SystemArgument1;
                SystemArgument2 = Dpc->SystemArgument2;

                /* Decrease the queue depth */
                DpcData->DpcQueueDepth--;

#if DBG
                /* Clear DPC Time */
                Prcb->DebugDpcTime = 0;
#endif

                /* Release the lock */
                KeReleaseSpinLockFromDpcLevel(&DpcData->DpcLock);

                /* Re-enable interrupts */
                _enable();

                /* Call the DPC */
                DeferredRoutine(Dpc,
                                DeferredContext,
                                SystemArgument1,
                                SystemArgument2);
                ASSERT(KeGetCurrentIrql() == DISPATCH_LEVEL);

                /* Disable interrupts and keep looping */
                _disable();
            }
            else
            {
                /* The queue should be flushed now */
                ASSERT(DpcData->DpcQueueDepth == 0);

                /* Release DPC Lock */
                KeReleaseSpinLockFromDpcLevel(&DpcData->DpcLock);
            }
        }

        /* Clear DPC Flags */
        Prcb->DpcRoutineActive = FALSE;
        Prcb->DpcInterruptRequested = FALSE;

#ifdef CONFIG_SMP
        /* Check if we have deferred threads */
        if (Prcb->DeferredReadyListHead.Next)
        {

            /* Re-enable interrupts and raise to synch */
            _enable();
            OldIrql = KeRaiseIrqlToSynchLevel();

            /* Process deferred threads */
            KiProcessDeferredReadyList(Prcb);

            /* Lower IRQL back and disable interrupts */
            KeLowerIrql(OldIrql);
            _disable();
        }
#endif
    } while (DpcData->DpcQueueDepth != 0);
}

Referenced by KiDispatchInterrupt(), and KiIdleLoop().

KiTimerExpiration()

VOID NTAPI KiTimerExpiration	(	IN PKDPC	Dpc,
		IN PVOID	DeferredContext,
		IN PVOID	SystemArgument1,
		IN PVOID	SystemArgument2
	)

Definition at line 79 of file dpc.c.

{
    ULARGE_INTEGER SystemTime, InterruptTime;
    LARGE_INTEGER Interval;
    LONG Limit, Index, i;
    ULONG Timers, ActiveTimers, DpcCalls;
    PLIST_ENTRY ListHead, NextEntry;
    KIRQL OldIrql;
    PKTIMER Timer;
    PKDPC TimerDpc;
    ULONG Period;
    DPC_QUEUE_ENTRY DpcEntry[MAX_TIMER_DPCS];
    PKSPIN_LOCK_QUEUE LockQueue;
    PKPRCB Prcb = KeGetCurrentPrcb();

    /* Disable interrupts */
    _disable();

    /* Query system and interrupt time */
    KeQuerySystemTime((PLARGE_INTEGER)&SystemTime);
    InterruptTime.QuadPart = KeQueryInterruptTime();
    Limit = KeTickCount.LowPart;

    /* Bring interrupts back */
    _enable();

    /* Get the index of the timer and normalize it */
    Index = PtrToLong(SystemArgument1);
    if ((Limit - Index) >= TIMER_TABLE_SIZE)
    {
        /* Normalize it */
        Limit = Index + TIMER_TABLE_SIZE - 1;
    }

    /* Setup index and actual limit */
    Index--;
    Limit &= (TIMER_TABLE_SIZE - 1);

    /* Setup accounting data */
    DpcCalls = 0;
    Timers = 24;
    ActiveTimers = 4;

    /* Lock the Database and Raise IRQL */
    OldIrql = KiAcquireDispatcherLock();

    /* Start expiration loop */
    do
    {
        /* Get the current index */
        Index = (Index + 1) & (TIMER_TABLE_SIZE - 1);

        /* Get list pointers and loop the list */
        ListHead = &KiTimerTableListHead[Index].Entry;
        while (ListHead != ListHead->Flink)
        {
            /* Lock the timer and go to the next entry */
            LockQueue = KiAcquireTimerLock(Index);
            NextEntry = ListHead->Flink;

            /* Get the current timer and check its due time */
            Timers--;
            Timer = CONTAINING_RECORD(NextEntry, KTIMER, TimerListEntry);
            if ((NextEntry != ListHead) &&
                (Timer->DueTime.QuadPart <= InterruptTime.QuadPart))
            {
                /* It's expired, remove it */
                ActiveTimers--;
                KiRemoveEntryTimer(Timer);

                /* Make it non-inserted, unlock it, and signal it */
                Timer->Header.Inserted = FALSE;
                KiReleaseTimerLock(LockQueue);
                Timer->Header.SignalState = 1;

                /* Get the DPC and period */
                TimerDpc = Timer->Dpc;
                Period = Timer->Period;

                /* Check if there's any waiters */
                if (!IsListEmpty(&Timer->Header.WaitListHead))
                {
                    /* Check the type of event */
                    if (Timer->Header.Type == TimerNotificationObject)
                    {
                        /* Unwait the thread */
                        KxUnwaitThread(&Timer->Header, IO_NO_INCREMENT);
                    }
                    else
                    {
                        /* Otherwise unwait the thread and signal the timer */
                        KxUnwaitThreadForEvent((PKEVENT)Timer, IO_NO_INCREMENT);
                    }
                }

                /* Check if we have a period */
                if (Period)
                {
                    /* Calculate the interval and insert the timer */
                    Interval.QuadPart = Int32x32To64(Period, -10000);
                    while (!KiInsertTreeTimer(Timer, Interval));
                }

                /* Check if we have a DPC */
                if (TimerDpc)
                {
#ifdef CONFIG_SMP
                    /*
                     * If the DPC is targeted to another processor,
                     * then insert it into that processor's DPC queue
                     * instead of delivering it now.
                     * If the DPC is a threaded DPC, and the current CPU
                     * has threaded DPCs enabled (KiExecuteDpc is actively parsing DPCs),
                     * then also insert it into the DPC queue for threaded delivery,
                     * instead of doing it here.
                     */
                    if (((TimerDpc->Number >= MAXIMUM_PROCESSORS) &&
                        ((TimerDpc->Number - MAXIMUM_PROCESSORS) != Prcb->Number)) ||
                        ((TimerDpc->Type == ThreadedDpcObject) && (Prcb->ThreadDpcEnable)))
                    {
                        /* Queue it */
                        KeInsertQueueDpc(TimerDpc,
                                         UlongToPtr(SystemTime.LowPart),
                                         UlongToPtr(SystemTime.HighPart));
                    }
                    else
#endif
                    {
                        /* Setup the DPC Entry */
                        DpcEntry[DpcCalls].Dpc = TimerDpc;
                        DpcEntry[DpcCalls].Routine = TimerDpc->DeferredRoutine;
                        DpcEntry[DpcCalls].Context = TimerDpc->DeferredContext;
                        DpcCalls++;
                        ASSERT(DpcCalls < MAX_TIMER_DPCS);
                    }
                }

                /* Check if we're done processing */
                if (!(ActiveTimers) || !(Timers))
                {
                    /* Release the dispatcher while doing DPCs */
                    KiReleaseDispatcherLock(DISPATCH_LEVEL);

                    /* Start looping all DPC Entries */
                    for (i = 0; DpcCalls; DpcCalls--, i++)
                    {
#if DBG
                        /* Clear DPC Time */
                        Prcb->DebugDpcTime = 0;
#endif

                        /* Call the DPC */
                        DpcEntry[i].Routine(DpcEntry[i].Dpc,
                                            DpcEntry[i].Context,
                                            UlongToPtr(SystemTime.LowPart),
                                            UlongToPtr(SystemTime.HighPart));
                    }

                    /* Reset accounting */
                    Timers = 24;
                    ActiveTimers = 4;

                    /* Lock the dispatcher database */
                    KiAcquireDispatcherLock();
                }
            }
            else
            {
                /* Check if the timer list is empty */
                if (NextEntry != ListHead)
                {
                    /* Sanity check */
                    ASSERT(KiTimerTableListHead[Index].Time.QuadPart <=
                           Timer->DueTime.QuadPart);

                    /* Update the time */
                    _disable();
                    KiTimerTableListHead[Index].Time.QuadPart =
                        Timer->DueTime.QuadPart;
                    _enable();
                }

                /* Release the lock */
                KiReleaseTimerLock(LockQueue);

                /* Check if we've scanned all the timers we could */
                if (!Timers)
                {
                    /* Release the dispatcher while doing DPCs */
                    KiReleaseDispatcherLock(DISPATCH_LEVEL);

                    /* Start looping all DPC Entries */
                    for (i = 0; DpcCalls; DpcCalls--, i++)
                    {
#if DBG
                        /* Clear DPC Time */
                        Prcb->DebugDpcTime = 0;
#endif

                        /* Call the DPC */
                        DpcEntry[i].Routine(DpcEntry[i].Dpc,
                                            DpcEntry[i].Context,
                                            UlongToPtr(SystemTime.LowPart),
                                            UlongToPtr(SystemTime.HighPart));
                    }

                    /* Reset accounting */
                    Timers = 24;
                    ActiveTimers = 4;

                    /* Lock the dispatcher database */
                    KiAcquireDispatcherLock();
                }

                /* Done looping */
                break;
            }
        }
    } while (Index != Limit);

    /* Verify the timer table, on debug builds */
    if (KeNumberProcessors == 1) KiCheckTimerTable(InterruptTime);

    /* Check if we still have DPC entries */
    if (DpcCalls)
    {
        /* Release the dispatcher while doing DPCs */
        KiReleaseDispatcherLock(DISPATCH_LEVEL);

        /* Start looping all DPC Entries */
        for (i = 0; DpcCalls; DpcCalls--, i++)
        {
#if DBG
            /* Clear DPC Time */
            Prcb->DebugDpcTime = 0;
#endif

            /* Call the DPC */
            DpcEntry[i].Routine(DpcEntry[i].Dpc,
                                DpcEntry[i].Context,
                                UlongToPtr(SystemTime.LowPart),
                                UlongToPtr(SystemTime.HighPart));
        }

        /* Lower IRQL if we need to */
        if (OldIrql != DISPATCH_LEVEL) KeLowerIrql(OldIrql);
    }
    else
    {
        /* Unlock the dispatcher */
        KiReleaseDispatcherLock(OldIrql);
    }
}

Referenced by KiInitializeKernel(), KiInitSystem(), and KiRetireDpcList().

KiTimerListExpire()

VOID FASTCALL KiTimerListExpire	(	IN PLIST_ENTRY	ExpiredListHead,
		IN KIRQL	OldIrql
	)

Definition at line 338 of file dpc.c.

{
    ULARGE_INTEGER SystemTime;
    LARGE_INTEGER Interval;
    LONG i;
    ULONG DpcCalls = 0;
    PKTIMER Timer;
    PKDPC TimerDpc;
    ULONG Period;
    DPC_QUEUE_ENTRY DpcEntry[MAX_TIMER_DPCS];
    PKPRCB Prcb = KeGetCurrentPrcb();

    /* Query system */
    KeQuerySystemTime((PLARGE_INTEGER)&SystemTime);

    /* Loop expired list */
    while (ExpiredListHead->Flink != ExpiredListHead)
    {
        /* Get the current timer */
        Timer = CONTAINING_RECORD(ExpiredListHead->Flink, KTIMER, TimerListEntry);

        /* Remove it */
        RemoveEntryList(&Timer->TimerListEntry);

        /* Not inserted */
        Timer->Header.Inserted = FALSE;

        /* Signal it */
        Timer->Header.SignalState = 1;

        /* Get the DPC and period */
        TimerDpc = Timer->Dpc;
        Period = Timer->Period;

        /* Check if there's any waiters */
        if (!IsListEmpty(&Timer->Header.WaitListHead))
        {
            /* Check the type of event */
            if (Timer->Header.Type == TimerNotificationObject)
            {
                /* Unwait the thread */
                KxUnwaitThread(&Timer->Header, IO_NO_INCREMENT);
            }
            else
            {
                /* Otherwise unwait the thread and signal the timer */
                KxUnwaitThreadForEvent((PKEVENT)Timer, IO_NO_INCREMENT);
            }
        }

        /* Check if we have a period */
        if (Period)
        {
            /* Calculate the interval and insert the timer */
            Interval.QuadPart = Int32x32To64(Period, -10000);
            while (!KiInsertTreeTimer(Timer, Interval));
        }

        /* Check if we have a DPC */
        if (TimerDpc)
        {
#ifdef CONFIG_SMP
            /*
             * If the DPC is targeted to another processor,
             * then insert it into that processor's DPC queue
             * instead of delivering it now.
             * If the DPC is a threaded DPC, and the current CPU
             * has threaded DPCs enabled (KiExecuteDpc is actively parsing DPCs),
             * then also insert it into the DPC queue for threaded delivery,
             * instead of doing it here.
             */
            if (((TimerDpc->Number >= MAXIMUM_PROCESSORS) &&
                ((TimerDpc->Number - MAXIMUM_PROCESSORS) != Prcb->Number)) ||
                ((TimerDpc->Type == ThreadedDpcObject) && (Prcb->ThreadDpcEnable)))
            {
                /* Queue it */
                KeInsertQueueDpc(TimerDpc,
                                 UlongToPtr(SystemTime.LowPart),
                                 UlongToPtr(SystemTime.HighPart));
            }
            else
#endif
            {
                /* Setup the DPC Entry */
                DpcEntry[DpcCalls].Dpc = TimerDpc;
                DpcEntry[DpcCalls].Routine = TimerDpc->DeferredRoutine;
                DpcEntry[DpcCalls].Context = TimerDpc->DeferredContext;
                DpcCalls++;
                ASSERT(DpcCalls < MAX_TIMER_DPCS);
            }
        }
    }

    /* Check if we still have DPC entries */
    if (DpcCalls)
    {
        /* Release the dispatcher while doing DPCs */
        KiReleaseDispatcherLock(DISPATCH_LEVEL);

        /* Start looping all DPC Entries */
        for (i = 0; DpcCalls; DpcCalls--, i++)
        {
#if DBG
            /* Clear DPC Time */
            Prcb->DebugDpcTime = 0;
#endif

            /* Call the DPC */
            DpcEntry[i].Routine(DpcEntry[i].Dpc,
                                DpcEntry[i].Context,
                                UlongToPtr(SystemTime.LowPart),
                                UlongToPtr(SystemTime.HighPart));
        }

        /* Lower IRQL */
        KeLowerIrql(OldIrql);
    }
    else
    {
        /* Unlock the dispatcher */
        KiReleaseDispatcherLock(OldIrql);
    }
}

Referenced by KeSetSystemTime().

Variable Documentation

KeThreadDpcEnable

BOOLEAN KeThreadDpcEnable

Definition at line 23 of file dpc.c.

Referenced by KeInitSystem().

KiAdjustDpcThreshold

ULONG KiAdjustDpcThreshold = 20

Definition at line 21 of file dpc.c.

Referenced by KeUpdateRunTime(), KiInitializeKernel(), KiInitSpinLocks(), and QSI_DEF().

KiDPCTimeout

ULONG KiDPCTimeout = 110

Definition at line 27 of file dpc.c.

Referenced by KeUpdateRunTime().

KiGenericCallDpcMutex

FAST_MUTEX KiGenericCallDpcMutex

Definition at line 24 of file dpc.c.

Referenced by KiInitializeKernel(), and KiInitSystem().

KiIdealDpcRate

ULONG KiIdealDpcRate = 20

Definition at line 22 of file dpc.c.

Referenced by KeUpdateRunTime(), and QSI_DEF().

KiMaximumDpcQueueDepth

ULONG KiMaximumDpcQueueDepth = 4

Definition at line 19 of file dpc.c.

Referenced by KeUpdateRunTime(), KiInitializeKernel(), KiInitSpinLocks(), and QSI_DEF().

KiMinimumDpcRate

ULONG KiMinimumDpcRate = 3

Definition at line 20 of file dpc.c.

Referenced by KiInitializeKernel(), KiInitSpinLocks(), and QSI_DEF().

KiTimeLimitIsrMicroseconds

ULONG KiTimeLimitIsrMicroseconds

Definition at line 26 of file dpc.c.

Referenced by KiInitMachineDependent().

KiTimerExpireDpc

KDPC KiTimerExpireDpc

Definition at line 25 of file dpc.c.

Referenced by KiCheckTimerTable(), KiInitializeKernel(), and KiInitSystem().