Source code of Windows XP (NT5)
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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
rxworkq.c
Abstract:
This module implements the Work queue routines for the Rx File system.
Author:
JoeLinn [JoeLinn] 8-8-94 Initial Implementation
Balan Sethu Raman [SethuR] 22-11-95 Implemented dispatch support for mini rdrs
Balan Sethu Raman [SethuR] 20-03-96 Delinked from executive worker threads
Notes:
There are two kinds of support for asynchronous resumption provided in the RDBSS.
The I/O requests that cannot be completed in the context of the thread in which
the request was made are posted to a file system process for completion.
The mini redirectors also require support for asynchronously completing requests as
well as post requests that cannot be completed at DPC level.
The requests for posting from the mini redirectors are classified into Critical(blocking and
non blocking requests. In order to ensure progress these requests are handled through
separate resources. There is no well known mechanism to ensure that the hyper critical
requests will not block.
The two functions that are available to all mini redirector writers are
RxDispatchToWorkerThread
RxPostToWorkerThread.
These two routines enable the mini redirector writer to make the appropriate space
time tradeoffs. The RxDispatchToWorkerThread trades time for reduction in space by
dynamically allocating the work item as and when required, while RxPostToWorkerThread
trades space for time by pre allocating a work item.
--*/
#include "precomp.h"
#pragma hdrstop
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, RxInitializeDispatcher)
#pragma alloc_text(PAGE, RxInitializeMRxDispatcher)
#pragma alloc_text(PAGE, RxSpinDownMRxDispatcher)
#pragma alloc_text(PAGE, RxInitializeWorkQueueDispatcher)
#pragma alloc_text(PAGE, RxInitializeWorkQueue)
#pragma alloc_text(PAGE, RxTearDownDispatcher)
#pragma alloc_text(PAGE, RxTearDownWorkQueueDispatcher)
#pragma alloc_text(PAGE, RxpSpinUpWorkerThreads)
#pragma alloc_text(PAGE, RxBootstrapWorkerThreadDispatcher)
#pragma alloc_text(PAGE, RxWorkerThreadDispatcher)
#endif
//
// The local debug trace level
//
#define Dbg (DEBUG_TRACE_FSP_DISPATCHER)
//
// had to steal this from ntifs.h in order to use ntsrv.h
extern POBJECT_TYPE *PsThreadType;
//
// Prototype forward declarations.
//
extern NTSTATUS
RxInitializeWorkQueueDispatcher(
PRX_WORK_QUEUE_DISPATCHER pDispatcher);
extern
VOID
RxInitializeWorkQueue(
PRX_WORK_QUEUE pWorkQueue,
WORK_QUEUE_TYPE WorkQueueType,
ULONG MaximumNumberOfWorkerThreads,
ULONG MinimumNumberOfWorkerThreads);
extern VOID
RxTearDownWorkQueueDispatcher(
PRX_WORK_QUEUE_DISPATCHER pDispatcher);
extern VOID
RxTearDownWorkQueue(
PRX_WORK_QUEUE pWorkQueue);
extern NTSTATUS
RxSpinUpWorkerThread(
PRX_WORK_QUEUE pWorkQueue,
PRX_WORKERTHREAD_ROUTINE Routine,
PVOID Parameter);
extern VOID
RxSpinUpWorkerThreads(
PRX_WORK_QUEUE pWorkQueue);
extern VOID
RxSpinDownWorkerThreads(
PRX_WORK_QUEUE pWorkQueue);
extern VOID
RxpWorkerThreadDispatcher(
IN PRX_WORK_QUEUE pWorkQueue,
IN PLARGE_INTEGER pWaitInterval);
VOID
RxBootstrapWorkerThreadDispatcher(
IN PRX_WORK_QUEUE pWorkQueue);
VOID
RxWorkerThreadDispatcher(
IN PRX_WORK_QUEUE pWorkQueue);
extern VOID
RxWorkItemDispatcher(
PVOID pContext);
extern VOID
RxSpinUpRequestsDispatcher(
PRX_DISPATCHER pDispatcher);
// The spin up requests thread
PETHREAD RxSpinUpRequestsThread = NULL;
//
// The delay parameter for KQUEUE wait requests in the RX_WORK_QUEUE implemenation
//
LARGE_INTEGER RxWorkQueueWaitInterval[MaximumWorkQueue];
LARGE_INTEGER RxSpinUpDispatcherWaitInterval;
//
// Currently the levels correspond to the three levels defined in ex.h
// Delayed,Critical and HyperCritical. As regards mini redirectors if any work
// is not dependent on any mini redirector/RDBSS resource, i.e., it will not wait
// it can be classified as a hypercritical1 work item. There is no good way to
// enforce this, therefore one should exercise great caution before classifying
// something as hypercritical.
//
NTSTATUS
RxInitializeDispatcher()
/*++
Routine Description:
This routine initializes the work queues dispatcher
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate failure to initialize
Notes:
The dispatching mechanism is implemented as a two tiered approach. Each
processor in the system is associated with a set of work queues. A best
effort is made to schedule all work emanating from a processor onto the
same processor. This prevents excessive sloshing of state information from
one processor cache to another.
For a given processor there are three work queues corresponding to three
levels of classification -- Delayed Work items, Critical Work items and
Hyper Critical work items. Each of these levels is associated with a
Kernel Queue (KQUEUE). The number of threads associated with each of these
queues can be independently controlled.
Currently the tuning parameters for the dispatcher are all hard coded. A
mechanism to intialize them from the registry needs to be implemented.
The following parameters associated with the dispatcher can be tuned ...
1) the wait time intervals associated with the kernel queue for each level.
2) the minimum and amximum number of worker threads associated with each
level.
--*/
{
ULONG ProcessorIndex,NumberOfProcessors;
NTSTATUS Status;
PAGED_CODE();
// Currently we set the number of processors to 1. In future the
// dispatcher can be tailored to multi processor implementation
// by appropriately initializing it as follows
// NumberOfProcessors = KeNumberProcessors;
NumberOfProcessors = 1;
RxFileSystemDeviceObject->DispatcherContext.NumberOfWorkerThreads = 0;
RxFileSystemDeviceObject->DispatcherContext.pTearDownEvent = NULL;
// Currently the default values for the wait intervals are set as
// 10 seconds ( expressed in system time units of 100 ns ticks ).
RxWorkQueueWaitInterval[DelayedWorkQueue].QuadPart = -10 * TICKS_PER_SECOND;
RxWorkQueueWaitInterval[CriticalWorkQueue].QuadPart = -10 * TICKS_PER_SECOND;
RxWorkQueueWaitInterval[HyperCriticalWorkQueue].QuadPart = -10 * TICKS_PER_SECOND;
RxSpinUpDispatcherWaitInterval.QuadPart = -60 * TICKS_PER_SECOND;
RxDispatcher.NumberOfProcessors = NumberOfProcessors;
RxDispatcher.OwnerProcess = IoGetCurrentProcess();
RxDispatcher.pWorkQueueDispatcher = &RxDispatcherWorkQueues;
if (RxDispatcher.pWorkQueueDispatcher != NULL) {
for (
ProcessorIndex = 0;
ProcessorIndex < NumberOfProcessors;
ProcessorIndex++
) {
Status = RxInitializeWorkQueueDispatcher(
&RxDispatcher.pWorkQueueDispatcher[ProcessorIndex]);
if (Status != STATUS_SUCCESS) {
break;
}
}
if (Status == STATUS_SUCCESS) {
Status = RxInitializeMRxDispatcher(RxFileSystemDeviceObject);
}
} else {
Status = STATUS_INSUFFICIENT_RESOURCES;
}
if (Status == STATUS_SUCCESS) {
HANDLE ThreadHandle;
KeInitializeEvent(
&RxDispatcher.SpinUpRequestsEvent,
NotificationEvent,
FALSE);
KeInitializeEvent(
&RxDispatcher.SpinUpRequestsTearDownEvent,
NotificationEvent,
FALSE);
InitializeListHead(
&RxDispatcher.SpinUpRequests);
RxDispatcher.State = RxDispatcherActive;
KeInitializeSpinLock(&RxDispatcher.SpinUpRequestsLock);
Status = PsCreateSystemThread(
&ThreadHandle,
PROCESS_ALL_ACCESS,
NULL,
NULL,
NULL,
RxSpinUpRequestsDispatcher,
&RxDispatcher);
if (NT_SUCCESS(Status)) {
// Close the handle so the thread can die when needed
ZwClose(ThreadHandle);
}
}
return Status;
}
NTSTATUS
RxInitializeMRxDispatcher(PRDBSS_DEVICE_OBJECT pMRxDeviceObject)
/*++
Routine Description:
This routine initializes the dispatcher context for a mini rdr
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate failure to initialize
Notes:
--*/
{
PAGED_CODE();
pMRxDeviceObject->DispatcherContext.NumberOfWorkerThreads = 0;
pMRxDeviceObject->DispatcherContext.pTearDownEvent = NULL;
return STATUS_SUCCESS;
}
NTSTATUS
RxSpinDownMRxDispatcher(PRDBSS_DEVICE_OBJECT pMRxDeviceObject)
/*++
Routine Description:
This routine tears down the dispatcher context for a mini rdr
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate failure to initialize
Notes:
--*/
{
LONG FinalRefCount;
KEVENT TearDownEvent;
KIRQL SavedIrql;
PAGED_CODE();
KeInitializeEvent(
&TearDownEvent,
NotificationEvent,
FALSE);
InterlockedIncrement(&pMRxDeviceObject->DispatcherContext.NumberOfWorkerThreads);
pMRxDeviceObject->DispatcherContext.pTearDownEvent = &TearDownEvent;
FinalRefCount = InterlockedDecrement(&pMRxDeviceObject->DispatcherContext.NumberOfWorkerThreads);
if (FinalRefCount > 0) {
KeWaitForSingleObject(
&TearDownEvent,
Executive,
KernelMode,
FALSE,
NULL);
} else {
InterlockedExchangePointer(
&pMRxDeviceObject->DispatcherContext.pTearDownEvent,
NULL);
}
ASSERT(pMRxDeviceObject->DispatcherContext.pTearDownEvent == NULL);
return STATUS_SUCCESS;
}
NTSTATUS
RxInitializeWorkQueueDispatcher(
PRX_WORK_QUEUE_DISPATCHER pDispatcher)
/*++
Routine Description:
This routine initializes the work queue dispatcher for a particular processor
Arguments:
pDispatcher - Work Queue Dispatcher
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate failure to initialize
Notes:
For each of the work queues associated with a processor the minimum number of
worker threads and maximum number of worker threads can be independently
specified and tuned.
The two factors that influence these decision are (1) the cost of spinnning up/
spinning down worker threads and (2) the amount of resources consumed by an
idle worker thread.
Currently these numbers are hard coded, a desirable extension would be a mechanism
to initialize them from a registry setting. This will enable us to tune the
parameters easily. This has to be implemented.
--*/
{
NTSTATUS Status;
MM_SYSTEMSIZE SystemSize;
ULONG NumberOfCriticalWorkerThreads;
PAGED_CODE();
SystemSize = MmQuerySystemSize();
RxInitializeWorkQueue(
&pDispatcher->WorkQueue[DelayedWorkQueue],DelayedWorkQueue,2,1);
if (SystemSize == MmLargeSystem) {
NumberOfCriticalWorkerThreads = 10;
} else {
NumberOfCriticalWorkerThreads = 5;
}
RxInitializeWorkQueue(
&pDispatcher->WorkQueue[CriticalWorkQueue],
CriticalWorkQueue,
NumberOfCriticalWorkerThreads,
1);
RxInitializeWorkQueue(
&pDispatcher->WorkQueue[HyperCriticalWorkQueue],
HyperCriticalWorkQueue,
5,
1);
Status = RxSpinUpWorkerThread(
&pDispatcher->WorkQueue[HyperCriticalWorkQueue],
RxBootstrapWorkerThreadDispatcher,
&pDispatcher->WorkQueue[HyperCriticalWorkQueue]);
if (Status == STATUS_SUCCESS) {
Status = RxSpinUpWorkerThread(
&pDispatcher->WorkQueue[CriticalWorkQueue],
RxBootstrapWorkerThreadDispatcher,
&pDispatcher->WorkQueue[CriticalWorkQueue]);
}
if (Status == STATUS_SUCCESS) {
Status = RxSpinUpWorkerThread(
&pDispatcher->WorkQueue[DelayedWorkQueue],
RxBootstrapWorkerThreadDispatcher,
&pDispatcher->WorkQueue[DelayedWorkQueue]);
}
return Status;
}
VOID
RxInitializeWorkQueue(
PRX_WORK_QUEUE pWorkQueue,
WORK_QUEUE_TYPE WorkQueueType,
ULONG MaximumNumberOfWorkerThreads,
ULONG MinimumNumberOfWorkerThreads)
/*++
Routine Description:
This routine initializes a work queue
Arguments:
pWorkQueue - Work Queue Dispatcher
MaximumNumberOfWorkerThreads - the upper bound on worker threads
MinimumNumberOfWorkerThreads - the lower bound on the threads.
--*/
{
PAGED_CODE();
pWorkQueue->Type = (UCHAR)WorkQueueType;
pWorkQueue->State = RxWorkQueueActive;
pWorkQueue->SpinUpRequestPending = FALSE;
pWorkQueue->pRundownContext = NULL;
pWorkQueue->NumberOfWorkItemsDispatched = 0;
pWorkQueue->NumberOfWorkItemsToBeDispatched = 0;
pWorkQueue->CumulativeQueueLength = 0;
pWorkQueue->NumberOfSpinUpRequests = 0;
pWorkQueue->MaximumNumberOfWorkerThreads = MaximumNumberOfWorkerThreads;
pWorkQueue->MinimumNumberOfWorkerThreads = MinimumNumberOfWorkerThreads;
pWorkQueue->NumberOfActiveWorkerThreads = 0;
pWorkQueue->NumberOfIdleWorkerThreads = 0;
pWorkQueue->NumberOfFailedSpinUpRequests = 0;
pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse = 0;
ExInitializeWorkItem(&pWorkQueue->WorkQueueItemForTearDownWorkQueue,NULL,NULL);
ExInitializeWorkItem(&pWorkQueue->WorkQueueItemForSpinUpWorkerThread,NULL,NULL);
ExInitializeWorkItem(&pWorkQueue->WorkQueueItemForSpinDownWorkerThread,NULL,NULL);
pWorkQueue->WorkQueueItemForSpinDownWorkerThread.pDeviceObject = NULL;
pWorkQueue->WorkQueueItemForSpinUpWorkerThread.pDeviceObject = NULL;
pWorkQueue->WorkQueueItemForTearDownWorkQueue.pDeviceObject = NULL;
KeInitializeQueue(&pWorkQueue->Queue,MaximumNumberOfWorkerThreads);
KeInitializeSpinLock(&pWorkQueue->SpinLock);
}
NTSTATUS
RxTearDownDispatcher()
/*++
Routine Description:
This routine tears down the dispatcher
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate failure to initialize
--*/
{
LONG ProcessorIndex;
NTSTATUS Status;
PAGED_CODE();
if (RxDispatcher.pWorkQueueDispatcher != NULL) {
RxDispatcher.State = RxDispatcherInactive;
KeSetEvent(
&RxDispatcher.SpinUpRequestsEvent,
IO_NO_INCREMENT,
FALSE);
KeWaitForSingleObject(
&RxDispatcher.SpinUpRequestsTearDownEvent,
Executive,
KernelMode,
FALSE,
NULL);
if (RxSpinUpRequestsThread != NULL) {
if (!PsIsThreadTerminating(RxSpinUpRequestsThread)) {
// Wait for the thread to terminate.
KeWaitForSingleObject(
RxSpinUpRequestsThread,
Executive,
KernelMode,
FALSE,
NULL);
ASSERT(PsIsThreadTerminating(RxSpinUpRequestsThread));
}
ObDereferenceObject(RxSpinUpRequestsThread);
}
for (
ProcessorIndex = 0;
ProcessorIndex < RxDispatcher.NumberOfProcessors;
ProcessorIndex++
) {
RxTearDownWorkQueueDispatcher(&RxDispatcher.pWorkQueueDispatcher[ProcessorIndex]);
}
//RxFreePool(RxDispatcher.pWorkQueueDispatcher);
}
return STATUS_SUCCESS;
}
VOID
RxTearDownWorkQueueDispatcher(
PRX_WORK_QUEUE_DISPATCHER pDispatcher)
/*++
Routine Description:
This routine tears dwon the work queue dispatcher for a particular processor
Arguments:
pDispatcher - Work Queue Dispatcher
--*/
{
PAGED_CODE();
RxTearDownWorkQueue(
&pDispatcher->WorkQueue[DelayedWorkQueue]);
RxTearDownWorkQueue(
&pDispatcher->WorkQueue[CriticalWorkQueue]);
RxTearDownWorkQueue(
&pDispatcher->WorkQueue[HyperCriticalWorkQueue]);
}
VOID
RxTearDownWorkQueue(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine tears down a work queue
Arguments:
pWorkQueue - Work Queue
Notes:
Tearing down a work queue is a more complex process when compared to initializing
a work queue. This is because of the threads associated with the queue. In order
to ensure that the work queue can be torn down correctly each of the threads
associated with the queue must be spun down correctly.
This is accomplished by changing the state of the work queue from
RxWorkQueueActive to RxWorkQueueRundownInProgress. This prevents further requests
from being inserted into the queue. Having done that the currently active threads
must be spundown.
The spinning down process is accelerated by posting a dummy work item onto the
work queue so that the waits are immediately satisfied.
--*/
{
KIRQL SavedIrql;
ULONG NumberOfActiveThreads;
PLIST_ENTRY pFirstListEntry,pNextListEntry;
PRX_WORK_QUEUE_RUNDOWN_CONTEXT pRundownContext;
pRundownContext = (PRX_WORK_QUEUE_RUNDOWN_CONTEXT)
RxAllocatePoolWithTag(
NonPagedPool,
sizeof(RX_WORK_QUEUE_RUNDOWN_CONTEXT) +
pWorkQueue->MaximumNumberOfWorkerThreads * sizeof(PETHREAD),
RX_WORKQ_POOLTAG);
if (pRundownContext != NULL) {
KeInitializeEvent(
&pRundownContext->RundownCompletionEvent,
NotificationEvent,
FALSE);
pRundownContext->NumberOfThreadsSpunDown = 0;
pRundownContext->ThreadPointers = (PETHREAD *)(pRundownContext + 1);
KeAcquireSpinLock(&pWorkQueue->SpinLock,&SavedIrql);
ASSERT((pWorkQueue->pRundownContext == NULL) &&
(pWorkQueue->State == RxWorkQueueActive));
pWorkQueue->pRundownContext = pRundownContext;
pWorkQueue->State = RxWorkQueueRundownInProgress;
NumberOfActiveThreads = pWorkQueue->NumberOfActiveWorkerThreads;
KeReleaseSpinLock(&pWorkQueue->SpinLock,SavedIrql);
if (NumberOfActiveThreads > 0) {
pWorkQueue->WorkQueueItemForTearDownWorkQueue.pDeviceObject = RxFileSystemDeviceObject;
InterlockedIncrement(&RxFileSystemDeviceObject->DispatcherContext.NumberOfWorkerThreads);
ExInitializeWorkItem(&pWorkQueue->WorkQueueItemForTearDownWorkQueue,RxSpinDownWorkerThreads,pWorkQueue);
KeInsertQueue(&pWorkQueue->Queue,&pWorkQueue->WorkQueueItemForTearDownWorkQueue.List);
KeWaitForSingleObject(
&pWorkQueue->pRundownContext->RundownCompletionEvent,
Executive,
KernelMode,
FALSE,
NULL);
}
if (pRundownContext->NumberOfThreadsSpunDown > 0) {
LONG Index = 0;
for (
Index = pRundownContext->NumberOfThreadsSpunDown - 1;
Index >= 0;
Index--
) {
PETHREAD pThread;
pThread = pRundownContext->ThreadPointers[Index];
ASSERT(pThread != NULL);
if (!PsIsThreadTerminating(pThread)) {
// Wait for the thread to terminate.
KeWaitForSingleObject(
pThread,
Executive,
KernelMode,
FALSE,
NULL);
ASSERT(PsIsThreadTerminating(pThread));
}
ObDereferenceObject(pThread);
}
}
RxFreePool(pRundownContext);
}
ASSERT(pWorkQueue->NumberOfActiveWorkerThreads == 0);
pFirstListEntry = KeRundownQueue(&pWorkQueue->Queue);
if (pFirstListEntry != NULL) {
pNextListEntry = pFirstListEntry;
do {
PWORK_QUEUE_ITEM pWorkQueueItem;
pWorkQueueItem = (PWORK_QUEUE_ITEM)
CONTAINING_RECORD(
pNextListEntry,
WORK_QUEUE_ITEM,
List);
pNextListEntry = pNextListEntry->Flink;
if (pWorkQueueItem->WorkerRoutine == RxWorkItemDispatcher) {
RxFreePool(pWorkQueueItem);
}
} while (pNextListEntry != pFirstListEntry);
}
}
NTSTATUS
RxSpinUpWorkerThread(
PRX_WORK_QUEUE pWorkQueue,
PRX_WORKERTHREAD_ROUTINE Routine,
PVOID Parameter)
/*++
Routine Description:
This routine spins up a worker thread associated with the given queue.
Arguments:
pWorkQueue - the WorkQueue instance.
Routine - the thread routine
Parameter - the thread routine parameter
Return Value:
STATUS_SUCCESS if successful,
otherwise appropriate error code
--*/
{
NTSTATUS Status;
HANDLE ThreadHandle;
KIRQL SavedIrql;
PAGED_CODE();
KeAcquireSpinLock(&pWorkQueue->SpinLock,&SavedIrql);
if( pWorkQueue->State == RxWorkQueueActive )
{
pWorkQueue->NumberOfActiveWorkerThreads++;
Status = STATUS_SUCCESS;
//RxLogRetail(("SpinUpWT %x %d %d\n", pWorkQueue, pWorkQueue->State, pWorkQueue->NumberOfActiveWorkerThreads ));
}
else
{
Status = STATUS_UNSUCCESSFUL;
RxLogRetail(("SpinUpWT Fail %x %d %d\n", pWorkQueue, pWorkQueue->State, pWorkQueue->NumberOfActiveWorkerThreads ));
//DbgPrint("[dkruse] RDBSS would have crashed here without this fix!\n");
}
KeReleaseSpinLock(&pWorkQueue->SpinLock, SavedIrql );
if( NT_SUCCESS(Status) )
{
Status = PsCreateSystemThread(
&ThreadHandle,
PROCESS_ALL_ACCESS,
NULL,
NULL,
NULL,
Routine,
Parameter);
if (NT_SUCCESS(Status)) {
// Close the handle so the thread can die when needed
ZwClose(ThreadHandle);
} else {
// Log the inability to create a worker thread.
RxLog(("WorkQ: %lx SpinUpStat %lx\n",pWorkQueue,Status));
RxWmiLogError(Status,
LOG,
RxSpinUpWorkerThread,
LOGPTR(pWorkQueue)
LOGULONG(Status));
// Change the thread count back, and set the rundown completion event if necessary
KeAcquireSpinLock( &pWorkQueue->SpinLock, &SavedIrql );
pWorkQueue->NumberOfActiveWorkerThreads--;
pWorkQueue->NumberOfFailedSpinUpRequests++;
if( (pWorkQueue->NumberOfActiveWorkerThreads == 0) &&
(pWorkQueue->State == RxWorkQueueRundownInProgress) )
{
KeSetEvent(
&pWorkQueue->pRundownContext->RundownCompletionEvent,
IO_NO_INCREMENT,
FALSE);
}
RxLogRetail(("SpinUpWT Fail2 %x %d %d\n", pWorkQueue, pWorkQueue->State, pWorkQueue->NumberOfActiveWorkerThreads ));
KeReleaseSpinLock( &pWorkQueue->SpinLock, SavedIrql );
}
}
return Status;
}
VOID
RxpSpinUpWorkerThreads(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine ensures that the dispatcher is not torn down while requests
are pending in the kernel worker threads for spin ups
Arguments:
pWorkQueue - the WorkQueue instance.
Notes:
There is implicit reliance on the fact that the RxDispatcher owner process
is the same as the system process. If this is not TRUE then an alternate
way needs to be implemented for ensuring that spinup requests are not stuck
behind other requests.
--*/
{
LONG NumberOfWorkerThreads;
PAGED_CODE();
ASSERT(IoGetCurrentProcess() == RxDispatcher.OwnerProcess);
RxSpinUpWorkerThreads(pWorkQueue);
NumberOfWorkerThreads = InterlockedDecrement(
&RxFileSystemDeviceObject->DispatcherContext.NumberOfWorkerThreads);
if (NumberOfWorkerThreads == 0) {
PKEVENT pTearDownEvent;
pTearDownEvent = (PKEVENT)
InterlockedExchangePointer(
&RxFileSystemDeviceObject->DispatcherContext.pTearDownEvent,
NULL);
if (pTearDownEvent != NULL) {
KeSetEvent(
pTearDownEvent,
IO_NO_INCREMENT,
FALSE);
}
}
}
VOID
RxSpinUpRequestsDispatcher(
PRX_DISPATCHER pDispatcher)
/*++
Routine Description:
This routine ensures that there is an independent thread to handle spinup
requests for all types of threads. This routine will be active as long as
the dispatcher is active
Arguments:
pDispatcher - the dispatcher instance.
Notes:
There is implicit reliance on the fact that the RxDispatcher owner process
is the same as the system process. If this is not TRUE then an alternate
way needs to be implemented for ensuring that spinup requests are not stuck
behind other requests.
--*/
{
PETHREAD ThisThread;
NTSTATUS Status;
RxDbgTrace(0,Dbg,("+++++ Worker SpinUp Requests Thread Startup %lx\n",PsGetCurrentThread()));
ThisThread = PsGetCurrentThread();
Status = ObReferenceObjectByPointer(
ThisThread,
THREAD_ALL_ACCESS,
*PsThreadType,
KernelMode);
if (Status == STATUS_SUCCESS) {
RxSpinUpRequestsThread = ThisThread;
for (;;) {
NTSTATUS Status;
RX_DISPATCHER_STATE State;
KIRQL SavedIrql;
LIST_ENTRY SpinUpRequests;
PLIST_ENTRY pListEntry;
InitializeListHead(&SpinUpRequests);
Status = KeWaitForSingleObject(
&pDispatcher->SpinUpRequestsEvent,
Executive,
KernelMode,
FALSE,
&RxSpinUpDispatcherWaitInterval);
ASSERT((Status == STATUS_SUCCESS) || (Status == STATUS_TIMEOUT));
KeAcquireSpinLock(
&pDispatcher->SpinUpRequestsLock,
&SavedIrql);
RxTransferList(
&SpinUpRequests,
&pDispatcher->SpinUpRequests);
State = pDispatcher->State;
KeResetEvent(
&pDispatcher->SpinUpRequestsEvent);
KeReleaseSpinLock(
&pDispatcher->SpinUpRequestsLock,
SavedIrql);
// Process the spin up requests
while (!IsListEmpty(&SpinUpRequests)) {
PRX_WORKERTHREAD_ROUTINE Routine;
PVOID pParameter;
PWORK_QUEUE_ITEM pWorkQueueItem;
PRX_WORK_QUEUE pWorkQueue;
LONG ItemInUse;
pListEntry = RemoveHeadList(&SpinUpRequests);
pWorkQueueItem = (PWORK_QUEUE_ITEM)
CONTAINING_RECORD(
pListEntry,
WORK_QUEUE_ITEM,
List);
Routine = pWorkQueueItem->WorkerRoutine;
pParameter = pWorkQueueItem->Parameter;
pWorkQueue = (PRX_WORK_QUEUE)pParameter;
ItemInUse = InterlockedDecrement(&pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse);
RxLog(("WORKQ:SR %lx %lx\n", Routine, pParameter ));
RxWmiLog(LOG,
RxSpinUpRequestsDispatcher,
LOGPTR(Routine)
LOGPTR(pParameter));
Routine(pParameter);
}
if (State != RxDispatcherActive) {
KeSetEvent(
&pDispatcher->SpinUpRequestsTearDownEvent,
IO_NO_INCREMENT,
FALSE);
break;
}
}
}
PsTerminateSystemThread(STATUS_SUCCESS);
}
VOID
RxSpinUpWorkerThreads(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine spins up one or more worker thread associated with the given queue.
Arguments:
pWorkQueue - the WorkQueue instance.
Return Value:
STATUS_SUCCESS if successful,
otherwise appropriate error code
--*/
{
NTSTATUS Status = STATUS_SUCCESS;
HANDLE ThreadHandle;
LONG NumberOfThreads;
KIRQL SavedIrql;
LONG ItemInUse;
if ((IoGetCurrentProcess() != RxDispatcher.OwnerProcess) ||
(KeGetCurrentIrql() != PASSIVE_LEVEL)) {
ItemInUse = InterlockedIncrement(&pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse);
if (ItemInUse > 1) {
// A work queue item is already on the SpinUpRequests waiting to be processed.
// No need to post another one.
InterlockedDecrement(&pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse);
return;
}
InterlockedIncrement(
&RxFileSystemDeviceObject->DispatcherContext.NumberOfWorkerThreads);
ExInitializeWorkItem(
(PWORK_QUEUE_ITEM)&pWorkQueue->WorkQueueItemForSpinUpWorkerThread,
RxpSpinUpWorkerThreads,
pWorkQueue);
KeAcquireSpinLock(&RxDispatcher.SpinUpRequestsLock, &SavedIrql);
InsertTailList(
&RxDispatcher.SpinUpRequests,
&pWorkQueue->WorkQueueItemForSpinUpWorkerThread.List);
KeSetEvent(
&RxDispatcher.SpinUpRequestsEvent,
IO_NO_INCREMENT,
FALSE);
KeReleaseSpinLock(&RxDispatcher.SpinUpRequestsLock,SavedIrql);
} else {
// Decide on the number of worker threads that need to be spun up.
KeAcquireSpinLock(&pWorkQueue->SpinLock, &SavedIrql);
if( pWorkQueue->State != RxWorkQueueRundownInProgress )
{
NumberOfThreads = pWorkQueue->MaximumNumberOfWorkerThreads -
pWorkQueue->NumberOfActiveWorkerThreads;
if (NumberOfThreads > pWorkQueue->NumberOfWorkItemsToBeDispatched) {
NumberOfThreads = pWorkQueue->NumberOfWorkItemsToBeDispatched;
}
}
else
{
// We're running down, so don't increment
NumberOfThreads = 0;
//DbgPrint( "[dkruse] Preventing rundown!\n" );
}
pWorkQueue->SpinUpRequestPending = FALSE;
KeReleaseSpinLock(&pWorkQueue->SpinLock, SavedIrql);
while (NumberOfThreads-- > 0) {
Status = RxSpinUpWorkerThread(
pWorkQueue,
RxWorkerThreadDispatcher,
pWorkQueue);
if (Status != STATUS_SUCCESS) {
break;
}
}
if (Status != STATUS_SUCCESS) {
ItemInUse = InterlockedIncrement(&pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse);
if (ItemInUse > 1) {
// A work queue item is already on the SpinUpRequests waiting to be processed.
// No need to post another one.
InterlockedDecrement(&pWorkQueue->WorkQueueItemForSpinUpWorkerThreadInUse);
return;
}
ExInitializeWorkItem(
(PWORK_QUEUE_ITEM)&pWorkQueue->WorkQueueItemForSpinUpWorkerThread,
RxpSpinUpWorkerThreads,
pWorkQueue);
KeAcquireSpinLock(&pWorkQueue->SpinLock, &SavedIrql);
pWorkQueue->SpinUpRequestPending = TRUE;
KeReleaseSpinLock(&pWorkQueue->SpinLock, SavedIrql);
KeAcquireSpinLock(&RxDispatcher.SpinUpRequestsLock, &SavedIrql);
// An attempt to spin up a worker thread failed. Reschedule the
// requests to attempt this operation later.
InterlockedIncrement(
&RxFileSystemDeviceObject->DispatcherContext.NumberOfWorkerThreads);
InsertTailList(
&RxDispatcher.SpinUpRequests,
&pWorkQueue->WorkQueueItemForSpinUpWorkerThread.List);
KeReleaseSpinLock(&RxDispatcher.SpinUpRequestsLock,SavedIrql);
}
}
}
VOID
RxSpinDownWorkerThreads(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine spins down one or more worker thread associated with the given queue.
Arguments:
pWorkQueue - the WorkQueue instance.
--*/
{
KIRQL SavedIrql;
BOOLEAN RepostSpinDownRequest = FALSE;
// Decide on the number of worker threads that need to be spun up.
KeAcquireSpinLock(&pWorkQueue->SpinLock, &SavedIrql);
if (pWorkQueue->NumberOfActiveWorkerThreads > 1) {
RepostSpinDownRequest = TRUE;
}
KeReleaseSpinLock(&pWorkQueue->SpinLock, SavedIrql);
if (RepostSpinDownRequest) {
if (pWorkQueue->WorkQueueItemForSpinDownWorkerThread.pDeviceObject == NULL) {
pWorkQueue->WorkQueueItemForSpinDownWorkerThread.pDeviceObject = RxFileSystemDeviceObject;
}
ExInitializeWorkItem(&pWorkQueue->WorkQueueItemForSpinDownWorkerThread,RxSpinDownWorkerThreads,pWorkQueue);
KeInsertQueue(&pWorkQueue->Queue,&pWorkQueue->WorkQueueItemForSpinDownWorkerThread.List);
}
}
BOOLEAN DumpDispatchRoutine = FALSE;
VOID
RxpWorkerThreadDispatcher(
IN PRX_WORK_QUEUE pWorkQueue,
IN PLARGE_INTEGER pWaitInterval)
/*++
Routine Description:
This routine dispatches a work item and frees the associated work item
Arguments:
pWorkQueue - the WorkQueue instance.
pWaitInterval - the interval for waiting on the KQUEUE.
--*/
{
NTSTATUS Status;
PLIST_ENTRY pListEntry;
PRX_WORK_QUEUE_ITEM pWorkQueueItem;
PRX_WORKERTHREAD_ROUTINE Routine;
PVOID pParameter;
BOOLEAN SpindownThread,DereferenceThread;
KIRQL SavedIrql;
PETHREAD ThisThread;
RxDbgTrace(0,Dbg,("+++++ Worker Thread Startup %lx\n",PsGetCurrentThread()));
InterlockedIncrement(&pWorkQueue->NumberOfIdleWorkerThreads);
ThisThread = PsGetCurrentThread();
Status = ObReferenceObjectByPointer(
ThisThread,
THREAD_ALL_ACCESS,
*PsThreadType,
KernelMode);
ASSERT(Status == STATUS_SUCCESS);
SpindownThread = FALSE;
DereferenceThread = FALSE;
for (;;) {
pListEntry = KeRemoveQueue(
&pWorkQueue->Queue,
KernelMode,
pWaitInterval);
if ((NTSTATUS)(ULONG_PTR)pListEntry != STATUS_TIMEOUT) {
LONG FinalRefCount;
PRDBSS_DEVICE_OBJECT pMRxDeviceObject;
InterlockedIncrement(&pWorkQueue->NumberOfWorkItemsDispatched);
InterlockedDecrement(&pWorkQueue->NumberOfWorkItemsToBeDispatched);
InterlockedDecrement(&pWorkQueue->NumberOfIdleWorkerThreads);
InitializeListHead(pListEntry);
pWorkQueueItem = (PRX_WORK_QUEUE_ITEM)
CONTAINING_RECORD(
pListEntry,
RX_WORK_QUEUE_ITEM,
List);
pMRxDeviceObject = pWorkQueueItem->pDeviceObject;
// This is a regular work item. Invoke the routine in the context of
// a try catch block.
Routine = pWorkQueueItem->WorkerRoutine;
pParameter = pWorkQueueItem->Parameter;
// Reset the fields in the Work item.
ExInitializeWorkItem(pWorkQueueItem,NULL,NULL);
pWorkQueueItem->pDeviceObject = NULL;
RxDbgTrace(0, Dbg, ("RxWorkerThreadDispatcher Routine(%lx) Parameter(%lx)\n",Routine,pParameter));
//RxLog(("WORKQ:Ex Dev(%lx) %lx %lx\n", pMRxDeviceObject,Routine, pParameter ));
//RxWmiLog(LOG,
// RxpWorkerThreadDispatcher,
// LOGPTR(pMRxDeviceObject)
// LOGPTR(Routine)
// LOGPTR(pParameter));
Routine(pParameter);
FinalRefCount = InterlockedDecrement(&pMRxDeviceObject->DispatcherContext.NumberOfWorkerThreads);
if (FinalRefCount == 0) {
PKEVENT pTearDownEvent;
pTearDownEvent = (PKEVENT)
InterlockedExchangePointer(
&pMRxDeviceObject->DispatcherContext.pTearDownEvent,
NULL);
if (pTearDownEvent != NULL) {
KeSetEvent(
pTearDownEvent,
IO_NO_INCREMENT,
FALSE);
}
}
InterlockedIncrement(&pWorkQueue->NumberOfIdleWorkerThreads);
}
KeAcquireSpinLock(&pWorkQueue->SpinLock,&SavedIrql);
switch (pWorkQueue->State) {
case RxWorkQueueActive:
{
if (pWorkQueue->NumberOfWorkItemsToBeDispatched > 0) {
// Delay spinning down a worker thread till the existing work
// items have been dispatched.
break;
}
}
// lack of break intentional.
// Ensure that the number of idle threads is not more than the
// minimum number of worker threads permitted for the work queue
case RxWorkQueueInactive:
{
ASSERT(pWorkQueue->NumberOfActiveWorkerThreads > 0);
if (pWorkQueue->NumberOfActiveWorkerThreads >
pWorkQueue->MinimumNumberOfWorkerThreads) {
SpindownThread = TRUE;
DereferenceThread = TRUE;
InterlockedDecrement(&pWorkQueue->NumberOfActiveWorkerThreads);
}
}
break;
case RxWorkQueueRundownInProgress:
{
PRX_WORK_QUEUE_RUNDOWN_CONTEXT pRundownContext;
pRundownContext = pWorkQueue->pRundownContext;
// The work queue is no longer active. Spin down all the worker
// threads associated with the work queue.
ASSERT(pRundownContext != NULL);
pRundownContext->ThreadPointers[pRundownContext->NumberOfThreadsSpunDown++] = ThisThread;
InterlockedDecrement(&pWorkQueue->NumberOfActiveWorkerThreads);
SpindownThread = TRUE;
DereferenceThread = FALSE;
if (pWorkQueue->NumberOfActiveWorkerThreads == 0) {
KeSetEvent(
&pWorkQueue->pRundownContext->RundownCompletionEvent,
IO_NO_INCREMENT,
FALSE);
}
}
break;
default:
ASSERT(!"Valid State For Work Queue");
}
if (SpindownThread) {
InterlockedDecrement(&pWorkQueue->NumberOfIdleWorkerThreads);
}
KeReleaseSpinLock(&pWorkQueue->SpinLock,SavedIrql);
if (SpindownThread) {
RxDbgTrace(0,Dbg,("----- Worker Thread Exit %lx\n",PsGetCurrentThread()));
break;
}
}
if (DereferenceThread) {
ObDereferenceObject(ThisThread);
}
if (DumpDispatchRoutine) {
// just to keep them around on free build for debug purpose
DbgPrint("Dispatch routine %lx %lx %lx\n",Routine,pParameter,pWorkQueueItem);
}
PsTerminateSystemThread(STATUS_SUCCESS);
}
VOID
RxBootstrapWorkerThreadDispatcher(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine is for worker threads that use a infinite time interval
for waiting on the KQUEUE data structure. These threads cannot be throtled
back and are used for ensuring that the bare minimum number of threads
are always active ( primarily startup purposes )
Arguments:
pWorkQueue - the WorkQueue instance.
--*/
{
PAGED_CODE();
RxpWorkerThreadDispatcher(pWorkQueue,NULL);
}
VOID
RxWorkerThreadDispatcher(
PRX_WORK_QUEUE pWorkQueue)
/*++
Routine Description:
This routine is for worker threads that use a finite time interval to wait
on the KQUEUE data structure. Such threads have a self regulatory mechanism
built in which causes them to spin down if the work load eases off. The
time interval is based on the type of the work queue
Arguments:
pWorkQueue - the WorkQueue instance.
--*/
{
PAGED_CODE();
RxpWorkerThreadDispatcher(
pWorkQueue,
&RxWorkQueueWaitInterval[pWorkQueue->Type]);
}
NTSTATUS
RxInsertWorkQueueItem(
PRDBSS_DEVICE_OBJECT pDeviceObject,
WORK_QUEUE_TYPE WorkQueueType,
PRX_WORK_QUEUE_ITEM pWorkQueueItem)
/*++
Routine Description:
This routine inserts a work item into the appropriate queue.
Arguments:
pDeviceObject - the device object
WorkQueueType - the type of work item
pWorkQueueItem - the work queue item
Return Value:
STATUS_SUCCESS -- successful
other status codes indicate error conditions
STATUS_INSUFFICIENT_RESOURCES -- could not dispatch
Notes:
This routine inserts the work item into the appropriate queue and spins
up a worker thread if required.
There are some extensions to this routine that needs to be implemented. These
have been delayed in order to get an idea of the costs and the benefits of
the various tradeoffs involved.
The current implementation follows a very simple logic in queueing work
from the various sources onto the same processor from which it originated.
The benefits associated with this approach are the prevention of cache/state
sloshing as the work is moved around from one processor to another. The
undesirable charecterstic is the skewing of work load on the various processors.
The important question that needs to be answered is when is it beneficial to
sacrifice the affinity to a processor. This depends upon the workload associated
with the current processor and the amount of information associated with the
given processor. The later is more difficult to determine.
--*/
{
NTSTATUS Status = STATUS_SUCCESS;
KIRQL SavedIrql;
BOOLEAN SpinUpWorkerThread = FALSE;
ULONG ProcessorNumber;
// If the dispatcher were on a per processor basis the ProcessorNumber
// would be indx for accessing the dispatcher data structure
// ProcessorNumber = KeGetCurrentProcessorNumber();
PRX_WORK_QUEUE_DISPATCHER pWorkQueueDispatcher;
PRX_WORK_QUEUE pWorkQueue;
ProcessorNumber = 0;
pWorkQueueDispatcher = &RxDispatcher.pWorkQueueDispatcher[ProcessorNumber];
pWorkQueue = &pWorkQueueDispatcher->WorkQueue[WorkQueueType];
if (RxDispatcher.State != RxDispatcherActive)
{
return STATUS_UNSUCCESSFUL;
}
KeAcquireSpinLock(&pWorkQueue->SpinLock, &SavedIrql);
if ((pWorkQueue->State == RxWorkQueueActive) &&
(pDeviceObject->DispatcherContext.pTearDownEvent == NULL)) {
pWorkQueueItem->pDeviceObject = pDeviceObject;
InterlockedIncrement(&pDeviceObject->DispatcherContext.NumberOfWorkerThreads);
pWorkQueue->CumulativeQueueLength += pWorkQueue->NumberOfWorkItemsToBeDispatched;
InterlockedIncrement(&pWorkQueue->NumberOfWorkItemsToBeDispatched);
if ((pWorkQueue->NumberOfIdleWorkerThreads < pWorkQueue->NumberOfWorkItemsToBeDispatched) &&
(pWorkQueue->NumberOfActiveWorkerThreads < pWorkQueue->MaximumNumberOfWorkerThreads) &&
(!pWorkQueue->SpinUpRequestPending)) {
pWorkQueue->SpinUpRequestPending = TRUE;
SpinUpWorkerThread = TRUE;
}
} else {
Status = STATUS_UNSUCCESSFUL;
}
KeReleaseSpinLock(&pWorkQueue->SpinLock, SavedIrql);
if (Status == STATUS_SUCCESS) {
KeInsertQueue(&pWorkQueue->Queue,&pWorkQueueItem->List);
if (SpinUpWorkerThread) {
RxSpinUpWorkerThreads(
pWorkQueue);
}
} else {
RxWmiLogError(Status,
LOG,
RxInsertWorkQueueItem,
LOGPTR(pDeviceObject)
LOGULONG(WorkQueueType)
LOGPTR(pWorkQueueItem)
LOGUSTR(pDeviceObject->DeviceName));
}
return Status;
}
VOID
RxWorkItemDispatcher(
PVOID pContext)
/*++
Routine Description:
This routine serves as a wrapper for dispatching a work item and for
performing the related cleanup actions
Arguments:
pContext - the Context parameter that is passed to the driver routine.
Notes:
There are two cases of dispatching to worker threads. When an instance is going to
be repeatedly dispatched time is conserved by allocating the WORK_QUEUE_ITEM as
part of the data structure to be dispatched. On the other hand if it is a very
infrequent operation space can be conserved by dynamically allocating and freeing
memory for the work queue item. This tradesoff time for space.
This routine implements a wrapper for those instances in which time was traded
off for space. It invokes the desired routine and frees the memory.
--*/
{
PRX_WORK_DISPATCH_ITEM pDispatchItem;
PRX_WORKERTHREAD_ROUTINE Routine;
PVOID Parameter;
pDispatchItem = (PRX_WORK_DISPATCH_ITEM)pContext;
Routine = pDispatchItem->DispatchRoutine;
Parameter = pDispatchItem->DispatchRoutineParameter;
//RxLog(("WORKQ:Ds %lx %lx\n", Routine, Parameter ));
//RxWmiLog(LOG,
// RxWorkItemDispatcher,
// LOGPTR(Routine)
// LOGPTR(Parameter));
Routine(Parameter);
RxFreePool(pDispatchItem);
}
NTSTATUS
RxDispatchToWorkerThread(
IN OUT PRDBSS_DEVICE_OBJECT pMRxDeviceObject,
IN WORK_QUEUE_TYPE WorkQueueType,
IN PRX_WORKERTHREAD_ROUTINE Routine,
IN PVOID pContext)
/*++
Routine Description:
This routine invokes the routine in the context of a worker thread.
Arguments:
pMRxDeviceObject - the device object of the corresponding mini redirector
WorkQueueType - the type of the work queue
Routine - routine to be invoked
pContext - the Context parameter that is passed to the driver routine.
Return Value:
STATUS_SUCCESS -- successful
STATUS_INSUFFICIENT_RESOURCES -- could not dispatch
Notes:
There are two cases of dispatching to worker threads. When an instance is going to
be repeatedly dispatched time is conserved by allocating the WORK_QUEUE_ITEM as
part of the data structure to be dispatched. On the other hand if it is a very
infrequent operation space can be conserved by dynamically allocating and freeing
memory for the work queue item. This tradesoff time for space.
--*/
{
NTSTATUS Status;
PRX_WORK_DISPATCH_ITEM pDispatchItem;
KIRQL SavedIrql;
pDispatchItem = RxAllocatePoolWithTag(
NonPagedPool,
sizeof(RX_WORK_DISPATCH_ITEM),
RX_WORKQ_POOLTAG);
if (pDispatchItem != NULL) {
pDispatchItem->DispatchRoutine = Routine;
pDispatchItem->DispatchRoutineParameter = pContext;
ExInitializeWorkItem(
&pDispatchItem->WorkQueueItem,
RxWorkItemDispatcher,
pDispatchItem);
Status = RxInsertWorkQueueItem(pMRxDeviceObject,WorkQueueType,&pDispatchItem->WorkQueueItem);
} else {
Status = STATUS_INSUFFICIENT_RESOURCES;
}
if (Status != STATUS_SUCCESS) {
if (pDispatchItem != NULL) {
RxFreePool(pDispatchItem);
}
RxLog(("WORKQ:Queue(D) %ld %lx %lx %lx\n", WorkQueueType,Routine,pContext,Status));
RxWmiLogError(Status,
LOG,
RxDispatchToWorkerThread,
LOGULONG(WorkQueueType)
LOGPTR(Routine)
LOGPTR(pContext)
LOGULONG(Status));
}
return Status;
}
NTSTATUS
RxPostToWorkerThread(
IN OUT PRDBSS_DEVICE_OBJECT pMRxDeviceObject,
IN WORK_QUEUE_TYPE WorkQueueType,
IN OUT PRX_WORK_QUEUE_ITEM pWorkQueueItem,
IN PRX_WORKERTHREAD_ROUTINE Routine,
IN PVOID pContext)
/*++
Routine Description:
This routine invokes the routine in the context of a worker thread.
Arguments:
WorkQueueType - the priority of the task at hand.
WorkQueueItem - the work queue item
Routine - routine to be invoked
pContext - the Context parameter that is passed to the driver routine.
Return Value:
STATUS_SUCCESS -- successful
STATUS_INSUFFICIENT_RESOURCES -- could not dispatch
Notes:
There are two cases of dispatching to worker threads. When an instance is going to
be repeatedly dispatched time is conserved by allocating the WORK_QUEUE_ITEM as
part of the data structure to be dispatched. On the other hand if it is a very
infrequent operation space can be conserved by dynamically allocating and freeing
memory for the work queue item. This tradesoff time for space.
--*/
{
NTSTATUS Status;
ExInitializeWorkItem( pWorkQueueItem,Routine,pContext );
Status = RxInsertWorkQueueItem(pMRxDeviceObject,WorkQueueType,pWorkQueueItem);
if (Status != STATUS_SUCCESS) {
RxLog(("WORKQ:Queue(P) %ld %lx %lx %lx\n", WorkQueueType,Routine,pContext,Status));
RxWmiLogError(Status,
LOG,
RxPostToWorkerThread,
LOGULONG(WorkQueueType)
LOGPTR(Routine)
LOGPTR(pContext)
LOGULONG(Status));
}
return Status;
}
PEPROCESS
RxGetRDBSSProcess()
{
return RxData.OurProcess;
}