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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
worker.c
Abstract:
This module defines functions for the worker thread pool.
Author:
Gurdeep Singh Pall (gurdeep) Nov 13, 1997
Revision History:
lokeshs - extended/modified threadpool.
Rob Earhart (earhart) September 29, 2000 Split off from threads.c
Environment:
These routines are statically linked in the caller's executable and are callable only from user mode. They make use of Nt system services.
--*/
#include <ntos.h>
#include <ntrtl.h>
#include "ntrtlp.h"
#include "threads.h"
// Worker Thread Pool
// ------------------
// Clients can submit functions to be executed by a worker thread. Threads are
// created if the work queue exceeds a threshold. Clients can request that the
// function be invoked in the context of a I/O thread. I/O worker threads
// can be used for initiating asynchronous I/O requests. They are not terminated if
// there are pending IO requests. Worker threads terminate if inactivity exceeds a
// threshold.
// Clients can also associate IO completion requests with the IO completion port
// waited upon by the non I/O worker threads. One should not post overlapped IO requests
// in worker threads.
ULONG StartedWorkerInitialization ; // Used for Worker thread startup synchronization
ULONG CompletedWorkerInitialization ; // Used to check if Worker thread pool is initialized
ULONG NumFutureWorkItems = 0 ; // Future work items (timers, waits, &c to exec in workers)
ULONG NumFutureIOWorkItems = 0 ; // Future IO work items (timers, waits, &c to exec in IO workers)
ULONG NumIOWorkerThreads ; // Count of IO Worker Threads alive
ULONG NumWorkerThreads ; // Count of Worker Threads alive
ULONG NumMinWorkerThreads ; // Min worker threads should be alive: 1 if ioCompletion used, else 0
ULONG NumIOWorkRequests ; // Count of IO Work Requests pending
ULONG NumLongIOWorkRequests ; // IO Worker threads executing long worker functions
ULONG NumWorkRequests ; // Count of Work Requests pending.
ULONG NumQueuedWorkRequests; // Count of work requests pending on IO completion
ULONG NumLongWorkRequests ; // Worker threads executing long worker functions
ULONG NumExecutingWorkerThreads ; // Worker threads currently executing worker functions
ULONG TotalExecutedWorkRequests ; // Total worker requests that were picked up
ULONG OldTotalExecutedWorkRequests ; // Total worker requests since last timeout.
HANDLE WorkerThreadTimerQueue = NULL ; // Timer queue used by worker threads
HANDLE WorkerThreadTimer = NULL ; // Timer used by worker threads
RTL_CRITICAL_SECTION WorkerTimerCriticalSection; // Synchronizes access to the worker timer
ULONG LastThreadCreationTickCount ; // Tick count at which the last thread was created
LIST_ENTRY IOWorkerThreads ; // List of IOWorkerThreads
PRTLP_IOWORKER_TCB PersistentIOTCB ; // ptr to TCB of persistest IO worker thread
HANDLE WorkerCompletionPort ; // Completion port used for queuing tasks to Worker threads
RTL_CRITICAL_SECTION WorkerCriticalSection ; // Exclusion used by worker threads
NTSTATUSRtlpStartWorkerThread ( VOID );
VOIDRtlpWorkerThreadCancelTimer( VOID ){ if (! RtlTryEnterCriticalSection(&WorkerTimerCriticalSection)) { //
// Either another thread is setting a timer, or clearing it.
// Either way, there's no reason for us to clear the timer --
// return immediately.
//
return; }
__try { if (WorkerThreadTimer) { ASSERT(WorkerThreadTimerQueue); RtlDeleteTimer(WorkerThreadTimerQueue, WorkerThreadTimer, NULL); } } __finally {
WorkerThreadTimer = NULL;
RtlLeaveCriticalSection(&WorkerTimerCriticalSection);
}}
VOIDRtlpWorkerThreadTimerCallback( PVOID Context, BOOLEAN NotUsed )/*++
Routine Description:
This routine checks if new worker thread has to be created
Arguments: None
Return Value: None
--*/{ IO_COMPLETION_BASIC_INFORMATION Info ; BOOLEAN bCreateThread = FALSE ; NTSTATUS Status ; ULONG QueueLength, Threshold, ShortWorkRequests ;
Status = NtQueryIoCompletion( WorkerCompletionPort, IoCompletionBasicInformation, &Info, sizeof(Info), NULL ) ;
if (!NT_SUCCESS(Status)) return ;
QueueLength = Info.Depth ;
if (!QueueLength) { OldTotalExecutedWorkRequests = TotalExecutedWorkRequests ; return ; }
RtlEnterCriticalSection (&WorkerCriticalSection) ;
// if there are queued work items and no new work items have been scheduled
// in the last 30 seconds then create a new thread.
// this will take care of deadlocks.
// this will create a problem only if some thread is running for a long time
if (TotalExecutedWorkRequests == OldTotalExecutedWorkRequests) {
bCreateThread = TRUE ; }
// if there are a lot of queued work items, then create a new thread
{ ULONG NumEffWorkerThreads = NumWorkerThreads > NumLongWorkRequests ? NumWorkerThreads - NumLongWorkRequests : 0; ULONG ShortWorkRequests ; ULONG CapturedNumExecutingWorkerThreads;
ULONG ThreadCreationDampingTime = NumWorkerThreads < NEW_THREAD_THRESHOLD ? THREAD_CREATION_DAMPING_TIME1 : (NumWorkerThreads < 30 ? THREAD_CREATION_DAMPING_TIME2 : (NumWorkerThreads << 13)); // *100ms
Threshold = (NumWorkerThreads < MAX_WORKER_THREADS ? (NumEffWorkerThreads < 7 ? NumEffWorkerThreads*NumEffWorkerThreads : ((NumEffWorkerThreads<40) ? NEW_THREAD_THRESHOLD * NumEffWorkerThreads : NEW_THREAD_THRESHOLD2 * NumEffWorkerThreads)) : 0xffffffff) ;
CapturedNumExecutingWorkerThreads = NumExecutingWorkerThreads;
ShortWorkRequests = QueueLength + CapturedNumExecutingWorkerThreads > NumLongWorkRequests ? QueueLength + CapturedNumExecutingWorkerThreads - NumLongWorkRequests : 0;
if (LastThreadCreationTickCount > NtGetTickCount()) LastThreadCreationTickCount = NtGetTickCount() ;
if (ShortWorkRequests > Threshold && (LastThreadCreationTickCount + ThreadCreationDampingTime < NtGetTickCount())) { bCreateThread = TRUE ; }
}
if (bCreateThread && NumWorkerThreads<MaxThreads) {
RtlpStartWorkerThread(); RtlpWorkerThreadCancelTimer(); }
OldTotalExecutedWorkRequests = TotalExecutedWorkRequests ;
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
}
NTSTATUSRtlpWorkerThreadSetTimer( VOID ){ NTSTATUS Status; HANDLE NewTimerQueue; HANDLE NewTimer;
Status = STATUS_SUCCESS;
if (! RtlTryEnterCriticalSection(&WorkerTimerCriticalSection)) { //
// Either another thread is setting a timer, or clearing it.
// Either way, there's no reason for us to set the timer --
// return immediately.
//
return STATUS_SUCCESS; }
__try {
if (! WorkerThreadTimerQueue) { Status = RtlCreateTimerQueue(&NewTimerQueue); if (! NT_SUCCESS(Status)) { __leave; } WorkerThreadTimerQueue = NewTimerQueue; } ASSERT(WorkerThreadTimerQueue != NULL);
if (! WorkerThreadTimer) { Status = RtlCreateTimer( WorkerThreadTimerQueue, &NewTimer, RtlpWorkerThreadTimerCallback, NULL, 60000, 60000, WT_EXECUTEINTIMERTHREAD ) ; if (! NT_SUCCESS(Status)) { __leave; }
WorkerThreadTimer = NewTimer; }
} __finally {
RtlLeaveCriticalSection(&WorkerTimerCriticalSection);
}
return Status;}
#if _MSC_FULL_VER >= 13008827
#pragma warning(push)
#pragma warning(disable:4715) // Not all control paths return (due to infinite loop)
#endif
LONGRtlpWorkerThread ( PVOID Parameter )/*++
Routine Description:
All non I/O worker threads execute in this routine. Worker thread will try to terminate when it has not serviced a request for
STARTING_WORKER_SLEEP_TIME + STARTING_WORKER_SLEEP_TIME << 1 + ... STARTING_WORKER_SLEEP_TIME << MAX_WORKER_SLEEP_TIME_EXPONENT
Arguments:
HandlePtr - Pointer to our handle. N.B. This is closed by RtlpStartWorkerThread, but we're still responsible for the memory.
Return Value:
--*/{ NTSTATUS Status ; PVOID WorkerProc ; PVOID Context ; IO_STATUS_BLOCK IoSb ; ULONG SleepTime ; LARGE_INTEGER TimeOut ; ULONG Terminate ; PVOID Overlapped ;
UNREFERENCED_PARAMETER(Parameter);
#if DBG
DbgPrintEx(DPFLTR_RTLTHREADPOOL_ID, RTLP_THREADPOOL_TRACE_MASK, "Starting worker thread\n");#endif
// Set default sleep time for 40 seconds.
#define WORKER_IDLE_TIMEOUT 40000 // In Milliseconds
SleepTime = WORKER_IDLE_TIMEOUT ;
// Loop servicing I/O completion requests
for ( ; ; ) {
TimeOut.QuadPart = Int32x32To64( SleepTime, -10000 ) ;
Status = NtRemoveIoCompletion( WorkerCompletionPort, (PVOID) &WorkerProc, &Overlapped, &IoSb, &TimeOut ) ;
if (Status == STATUS_SUCCESS) {
TotalExecutedWorkRequests ++ ;//interlocked op not req
InterlockedIncrement(&NumExecutingWorkerThreads) ; InterlockedDecrement(&NumQueuedWorkRequests);
if (NumExecutingWorkerThreads == NumWorkerThreads && NumQueuedWorkRequests > 0) { RtlpWorkerThreadSetTimer(); }
// Call the work item.
// If IO APC, context1 contains number of IO bytes transferred, and context2
// contains the overlapped structure.
// If (IO)WorkerFunction, context1 contains the actual WorkerFunction to be
// executed and context2 contains the actual context
Context = (PVOID) IoSb.Information ;
RtlpApcCallout(WorkerProc, IoSb.Status, Context, Overlapped);
SleepTime = WORKER_IDLE_TIMEOUT ;
InterlockedDecrement(&NumExecutingWorkerThreads) ;
RtlpWorkerThreadCancelTimer();
} else if (Status == STATUS_TIMEOUT) {
// NtRemoveIoCompletion timed out. Check to see if have hit our limit
// on waiting. If so terminate.
Terminate = FALSE ;
RtlEnterCriticalSection (&WorkerCriticalSection) ;
// The thread terminates if there are > 1 threads and the queue is small
// OR if there is only 1 thread and there is no request pending
if (NumWorkerThreads > 1) {
ULONG NumEffWorkerThreads = NumWorkerThreads > NumLongWorkRequests ? NumWorkerThreads - NumLongWorkRequests : 0;
if (NumEffWorkerThreads<=NumMinWorkerThreads) {
Terminate = FALSE ;
} else {
//
// have been idle for very long time. terminate irrespective of number of
// work items. (This is useful when the set of runnable threads is taking
// care of all the work items being queued). dont terminate if
// (NumEffWorkerThreads == 1)
//
if (NumEffWorkerThreads > 1) { Terminate = TRUE ; } else { Terminate = FALSE ; }
}
} else {
if ( NumMinWorkerThreads == 0 && NumWorkRequests == 0 && NumFutureWorkItems == 0) {
Terminate = TRUE ;
} else {
Terminate = FALSE ;
}
}
if (Terminate) {
THREAD_BASIC_INFORMATION ThreadInfo; ULONG IsIoPending ;
Terminate = FALSE ;
Status = NtQueryInformationThread( NtCurrentThread(), ThreadIsIoPending, &IsIoPending, sizeof( IsIoPending ), NULL ); if (NT_SUCCESS( Status )) {
if (! IsIoPending ) Terminate = TRUE ; } }
if (Terminate) {
ASSERT(NumWorkerThreads > 0); NumWorkerThreads--;
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
RtlpExitThreadFunc( 0 );
} else {
// This is the condition where a request was queued *after* the
// thread woke up - ready to terminate because of inactivity. In
// this case dont terminate - service the completion port.
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
}
} else {
ASSERTMSG ("NtRemoveIoCompletion failed", (Status != STATUS_SUCCESS) && (Status != STATUS_TIMEOUT)) ;
}
}
return 1 ;}
#if _MSC_FULL_VER >= 13008827
#pragma warning(pop)
#endif
NTSTATUSRtlpStartWorkerThread ( VOID )/*++
Routine Description:
This routine starts a regular worker thread
Arguments:
Return Value:
NTSTATUS error codes resulting from attempts to create a thread STATUS_SUCCESS
--*/{ HANDLE ThreadHandle; ULONG CurrentTickCount; NTSTATUS Status;
// Create worker thread
Status = RtlpStartThreadpoolThread (RtlpWorkerThread, NULL, &ThreadHandle);
if (NT_SUCCESS(Status)) {
#if DBG
DbgPrintEx(DPFLTR_RTLTHREADPOOL_ID, RTLP_THREADPOOL_TRACE_MASK, "Created worker thread; handle %d (closing)\n", ThreadHandle);#endif
// We don't care about worker threads' handles.
NtClose(ThreadHandle);
// Update the time at which the current thread was created
LastThreadCreationTickCount = NtGetTickCount() ;
// Increment the count of the thread type created
NumWorkerThreads++;
} else {
#if DBG
DbgPrintEx(DPFLTR_RTLTHREADPOOL_ID, RTLP_THREADPOOL_TRACE_MASK, "Failed to create worker thread; status %p\n", Status);#endif
// Thread creation failed. If there is even one thread present do not return
// failure - else queue the request anyway.
if (NumWorkerThreads <= NumLongWorkRequests) {
return Status ; }
}
return STATUS_SUCCESS ;}
NTSTATUSRtlpInitializeWorkerThreadPool ( )/*++
Routine Description:
This routine initializes all aspects of the thread pool.
Arguments:
None
Return Value:
None
--*/{ NTSTATUS Status = STATUS_SUCCESS ; LARGE_INTEGER TimeOut ; SYSTEM_BASIC_INFORMATION BasicInfo;
// Initialize the timer component if it hasnt been done already
if (CompletedTimerInitialization != 1) {
Status = RtlpInitializeTimerThreadPool () ;
if ( !NT_SUCCESS(Status) ) return Status ;
}
// In order to avoid an explicit RtlInitialize() function to initialize the thread pool
// we use StartedInitialization and CompletedInitialization to provide us the necessary
// synchronization to avoid multiple threads from initializing the thread pool.
// This scheme does not work if RtlInitializeCriticalSection() fails - but in this case the
// caller has no choices left.
if (!InterlockedExchange(&StartedWorkerInitialization, 1L)) {
if (CompletedWorkerInitialization) InterlockedExchange( &CompletedWorkerInitialization, 0 ) ;
do {
// Initialize Critical Sections
Status = RtlInitializeCriticalSection( &WorkerCriticalSection ); if (!NT_SUCCESS(Status)) break ;
Status = RtlInitializeCriticalSection( &WorkerTimerCriticalSection ); if (! NT_SUCCESS(Status)) { RtlDeleteCriticalSection( &WorkerCriticalSection ); break; }
InitializeListHead (&IOWorkerThreads) ;
// get number of processors
Status = NtQuerySystemInformation ( SystemBasicInformation, &BasicInfo, sizeof(BasicInfo), NULL ) ;
if ( !NT_SUCCESS(Status) ) { BasicInfo.NumberOfProcessors = 1 ; }
// Create completion port used by worker threads
Status = NtCreateIoCompletion ( &WorkerCompletionPort, IO_COMPLETION_ALL_ACCESS, NULL, BasicInfo.NumberOfProcessors );
if (!NT_SUCCESS(Status)) { RtlDeleteCriticalSection( &WorkerCriticalSection ); RtlDeleteCriticalSection( &WorkerTimerCriticalSection ); break; }
} while ( FALSE ) ;
if (!NT_SUCCESS(Status) ) {
StartedWorkerInitialization = 0 ; InterlockedExchange( &CompletedWorkerInitialization, ~0 ) ; return Status ; }
// Signal that initialization has completed
InterlockedExchange (&CompletedWorkerInitialization, 1L) ;
} else {
LARGE_INTEGER Timeout ;
// Sleep 1 ms and see if the other thread has completed initialization
ONE_MILLISECOND_TIMEOUT(TimeOut) ;
while (!*((ULONG volatile *)&CompletedWorkerInitialization)) {
NtDelayExecution (FALSE, &TimeOut) ; }
if (CompletedWorkerInitialization != 1) return STATUS_NO_MEMORY ;
}
return NT_SUCCESS(Status) ? STATUS_SUCCESS : Status ;}
LONGRtlpIOWorkerThread ( PVOID Parameter )/*++
Routine Description:
All I/O worker threads execute in this routine. All the work requests execute as APCs in this thread.
Arguments:
HandlePtr - Pointer to our handle.
Return Value:
--*/{ #define IOWORKER_IDLE_TIMEOUT 40000 // In Milliseconds
LARGE_INTEGER TimeOut ; ULONG SleepTime = IOWORKER_IDLE_TIMEOUT ; PRTLP_IOWORKER_TCB ThreadCB ; // Control Block allocated on the
// heap by the parent thread
NTSTATUS Status ; BOOLEAN Terminate ;
ASSERT(Parameter != NULL);
ThreadCB = (PRTLP_IOWORKER_TCB) Parameter;
#if DBG
DbgPrintEx(DPFLTR_RTLTHREADPOOL_ID, RTLP_THREADPOOL_TRACE_MASK, "Starting IO worker thread\n");#endif
// Sleep alertably so that all the activity can take place
// in APCs
for ( ; ; ) {
// Set timeout for IdleTimeout
TimeOut.QuadPart = Int32x32To64( SleepTime, -10000 ) ;
Status = NtDelayExecution (TRUE, &TimeOut) ;
// Status is STATUS_SUCCESS only when it has timed out
if (Status != STATUS_SUCCESS) { continue ; }
//
// idle timeout. check if you can terminate the thread
//
Terminate = FALSE ;
RtlEnterCriticalSection (&WorkerCriticalSection) ;
// dont terminate if it is a persistent thread
if (ThreadCB->Flags & WT_EXECUTEINPERSISTENTIOTHREAD) {
TimeOut.LowPart = 0x0; TimeOut.HighPart = 0x80000000;
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
continue ; }
// The thread terminates if there are > 1 threads and the queue is small
// OR if there is only 1 thread and there is no request pending
if (NumIOWorkerThreads > 1) {
ULONG NumEffIOWorkerThreads = NumIOWorkerThreads > NumLongIOWorkRequests ? NumIOWorkerThreads - NumLongIOWorkRequests : 0; ULONG Threshold;
if (NumEffIOWorkerThreads == 0) {
Terminate = FALSE ;
} else {
// Check if we need to shrink worker thread pool
Threshold = NEW_THREAD_THRESHOLD * (NumEffIOWorkerThreads-1);
if (NumIOWorkRequests-NumLongIOWorkRequests < Threshold) {
Terminate = TRUE ;
} else {
Terminate = FALSE ; SleepTime <<= 1 ; } }
} else {
if (NumIOWorkRequests == 0 && NumFutureIOWorkItems == 0) {
// delay termination of last thread
if (SleepTime < 4*IOWORKER_IDLE_TIMEOUT) {
SleepTime <<= 1 ; Terminate = FALSE ;
} else {
Terminate = TRUE ; }
} else {
Terminate = FALSE ;
}
}
//
// terminate only if no io is pending
//
if (Terminate) {
NTSTATUS Status; THREAD_BASIC_INFORMATION ThreadInfo; ULONG IsIoPending ;
Terminate = FALSE ;
Status = NtQueryInformationThread( ThreadCB->ThreadHandle, ThreadIsIoPending, &IsIoPending, sizeof( IsIoPending ), NULL ); if (NT_SUCCESS( Status )) {
if (! IsIoPending ) Terminate = TRUE ; } }
if (Terminate) {
ASSERT(NumIOWorkerThreads > 0); NumIOWorkerThreads--;
RemoveEntryList (&ThreadCB->List) ; NtClose( ThreadCB->ThreadHandle ) ; RtlpFreeTPHeap( ThreadCB );
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
RtlpExitThreadFunc( 0 );
} else {
// This is the condition where a request was queued *after* the
// thread woke up - ready to terminate because of inactivity. In
// this case dont terminate - service the completion port.
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
} }
return 0 ; // Keep compiler happy
}
NTSTATUSRtlpStartIOWorkerThread ( )/*++
Routine Description:
This routine starts an I/O worker thread
N.B. Callers MUST hold the WorkerCriticalSection.
Arguments:
Return Value:
NTSTATUS error codes resulting from attempts to create a thread STATUS_SUCCESS
--*/{ ULONG CurrentTickCount ; NTSTATUS Status ; PRTLP_IOWORKER_TCB ThreadCB;
// Create the worker's control block
ThreadCB = (PRTLP_IOWORKER_TCB) RtlpAllocateTPHeap(sizeof(RTLP_IOWORKER_TCB), 0); if (! ThreadCB) { return STATUS_NO_MEMORY; }
// Fill in the control block
ThreadCB->Flags = 0; ThreadCB->LongFunctionFlag = FALSE;
// Create worker thread
Status = RtlpStartThreadpoolThread (RtlpIOWorkerThread, ThreadCB, &ThreadCB->ThreadHandle);
if (NT_SUCCESS(Status)) {
// Update the time at which the current thread was created,
// and insert the ThreadCB into the IO worker thread list.
LastThreadCreationTickCount = NtGetTickCount() ; NumIOWorkerThreads++; InsertHeadList(&IOWorkerThreads, &ThreadCB->List);
} else {
// Thread creation failed.
RtlpFreeTPHeap(ThreadCB);
// If there is even one thread present do not return
// failure since we can still service the work request.
if (NumIOWorkerThreads <= NumLongIOWorkRequests) {
return Status ;
} }
return STATUS_SUCCESS ;}
VOIDRtlpExecuteLongIOWorkItem ( PVOID Function, PVOID Context, PVOID ThreadCB )/*++
Routine Description:
Executes an IO Work function. RUNs in a APC in the IO Worker thread.
Arguments:
Function - Worker function to call
Context - Argument for the worker function.
NotUsed - Argument is not used in this function.
Return Value:
--*/{ RtlpWorkerCallout(Function, Context, NULL, NULL);
((PRTLP_IOWORKER_TCB)ThreadCB)->LongFunctionFlag = FALSE ;
RtlEnterCriticalSection(&WorkerCriticalSection);
// Decrement pending IO requests count
NumIOWorkRequests--;
// decrement pending long funcitons
NumLongIOWorkRequests--;
RtlLeaveCriticalSection(&WorkerCriticalSection);}
VOIDRtlpExecuteIOWorkItem ( PVOID Function, PVOID Context, PVOID NotUsed )/*++
Routine Description:
Executes an IO Work function. RUNs in a APC in the IO Worker thread.
Arguments:
Function - Worker function to call
Context - Argument for the worker function.
NotUsed - Argument is not used in this function.
Return Value:
--*/{ RtlpWorkerCallout(Function, Context, NULL, NULL);
RtlEnterCriticalSection(&WorkerCriticalSection);
// Decrement pending IO requests count
NumIOWorkRequests--;
RtlLeaveCriticalSection(&WorkerCriticalSection);}
NTSTATUSRtlpQueueIOWorkerRequest ( WORKERCALLBACKFUNC Function, PVOID Context, ULONG Flags )
/*++
Routine Description:
This routine queues up the request to be executed in an IO worker thread.
Arguments:
Function - Routine that is called by the worker thread
Context - Opaque pointer passed in as an argument to WorkerProc
Return Value:
--*/
{ NTSTATUS Status ; PRTLP_IOWORKER_TCB TCB ; BOOLEAN LongFunction = (Flags & WT_EXECUTELONGFUNCTION) ? TRUE : FALSE ; PLIST_ENTRY ple ;
if (Flags & WT_EXECUTEINPERSISTENTIOTHREAD) {
if (!PersistentIOTCB) { for (ple=IOWorkerThreads.Flink; ple!=&IOWorkerThreads; ple=ple->Flink) { TCB = CONTAINING_RECORD (ple, RTLP_IOWORKER_TCB, List) ; if (! TCB->LongFunctionFlag) break; }
if (ple == &IOWorkerThreads) { return STATUS_NO_MEMORY; }
PersistentIOTCB = TCB ; TCB->Flags |= WT_EXECUTEINPERSISTENTIOTHREAD ;
} else { TCB = PersistentIOTCB ; }
} else { for (ple=IOWorkerThreads.Flink; ple!=&IOWorkerThreads; ple=ple->Flink) {
TCB = CONTAINING_RECORD (ple, RTLP_IOWORKER_TCB, List) ;
// do not queue to the thread if it is executing a long function, or
// if you are queueing a long function and the thread is a persistent thread
if (! TCB->LongFunctionFlag && (! ((TCB->Flags&WT_EXECUTEINPERSISTENTIOTHREAD) && (Flags&WT_EXECUTELONGFUNCTION)))) { break ; }
}
if ((ple == &IOWorkerThreads) && (NumIOWorkerThreads<1)) {
#if DBG
DbgPrintEx(DPFLTR_RTLTHREADPOOL_ID, RTLP_THREADPOOL_WARNING_MASK, "Out of memory. " "Could not execute IOWorkItem(%x)\n", (ULONG_PTR)Function);#endif
return STATUS_NO_MEMORY; } else { ple = IOWorkerThreads.Flink; TCB = CONTAINING_RECORD (ple, RTLP_IOWORKER_TCB, List) ;
// treat it as a short function so that counters work fine.
LongFunction = FALSE; }
// In order to implement "fair" assignment of work items between IO worker threads
// each time remove the entry and reinsert at back.
RemoveEntryList (&TCB->List) ; InsertTailList (&IOWorkerThreads, &TCB->List) ; }
// Increment the outstanding work request counter
NumIOWorkRequests++; if (LongFunction) { NumLongIOWorkRequests++; TCB->LongFunctionFlag = TRUE ; }
// Queue an APC to the IoWorker Thread
Status = NtQueueApcThread( TCB->ThreadHandle, LongFunction? (PPS_APC_ROUTINE)RtlpExecuteLongIOWorkItem: (PPS_APC_ROUTINE)RtlpExecuteIOWorkItem, (PVOID)Function, Context, TCB );
if (! NT_SUCCESS( Status ) ) { NumIOWorkRequests--; if (LongFunction) NumLongIOWorkRequests--; }
return Status ;
}
NTSTATUSRtlSetIoCompletionCallback ( IN HANDLE FileHandle, IN APC_CALLBACK_FUNCTION CompletionProc, IN ULONG Flags )
/*++
Routine Description:
This routine binds an Handle and an associated callback function to the IoCompletionPort which queues work items to worker threads.
Arguments:
Handle - handle to be bound to the IO completion port
CompletionProc - callback function to be executed when an IO request pending on the IO handle completes.
Flags - Reserved. pass 0.
--*/
{ IO_STATUS_BLOCK IoSb ; FILE_COMPLETION_INFORMATION CompletionInfo ; NTSTATUS Status;
if (LdrpShutdownInProgress) { return STATUS_UNSUCCESSFUL; }
// Make sure that the worker thread pool is initialized as the file handle
// is bound to IO completion port.
if (CompletedWorkerInitialization != 1) {
Status = RtlpInitializeWorkerThreadPool () ;
if (! NT_SUCCESS(Status) ) return Status ;
}
//
// from now on NumMinWorkerThreads should be 1. If there is only 1 worker thread
// create a new one.
//
if ( NumMinWorkerThreads == 0 ) {
// Take lock for the global worker thread pool
RtlEnterCriticalSection (&WorkerCriticalSection) ;
if ((NumWorkerThreads-NumLongWorkRequests) == 0) {
Status = RtlpStartWorkerThread () ;
if ( ! NT_SUCCESS(Status) ) {
RtlLeaveCriticalSection (&WorkerCriticalSection) ; return Status ; } }
// from now on, there will be at least 1 worker thread
NumMinWorkerThreads = 1 ;
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
}
// bind to IoCompletionPort, which queues work items to worker threads
CompletionInfo.Port = WorkerCompletionPort ; CompletionInfo.Key = (PVOID) CompletionProc ;
Status = NtSetInformationFile ( FileHandle, &IoSb, //not initialized
&CompletionInfo, sizeof(CompletionInfo), FileCompletionInformation //enum flag
) ; return Status ;}
VOIDRtlpExecuteWorkerRequest ( NTSTATUS StatusIn, //not used
PVOID Context, PVOID WorkContext )/*++
Routine Description:
This routine executes a work item.
Arguments:
Context - contains context to be passed to the callback function.
WorkContext - contains callback function ptr and flags
Return Value:
Notes: This function executes in a worker thread or a timer thread if WT_EXECUTEINTIMERTHREAD flag is set.
--*/
{ PRTLP_WORK WorkEntry = (PRTLP_WORK) WorkContext; NTSTATUS Status;
RtlpWorkerCallout(WorkEntry->Function, Context, WorkEntry->ActivationContext, WorkEntry->ImpersonationToken);
RtlEnterCriticalSection(&WorkerCriticalSection); NumWorkRequests--; if (WorkEntry->Flags & WT_EXECUTELONGFUNCTION) { NumLongWorkRequests--; } RtlLeaveCriticalSection(&WorkerCriticalSection);
if (WorkEntry->ActivationContext != INVALID_ACTIVATION_CONTEXT) RtlReleaseActivationContext(WorkEntry->ActivationContext);
if (WorkEntry->ImpersonationToken) { NtClose(WorkEntry->ImpersonationToken); }
RtlpFreeTPHeap( WorkEntry ) ;}
NTSTATUSRtlpQueueWorkerRequest ( WORKERCALLBACKFUNC Function, PVOID Context, ULONG Flags )/*++
Routine Description:
This routine queues up the request to be executed in a worker thread.
Arguments:
Function - Routine that is called by the worker thread
Context - Opaque pointer passed in as an argument to WorkerProc
Flags - flags passed to RtlQueueWorkItem
Return Value:
--*/
{ NTSTATUS Status ; PRTLP_WORK WorkEntry ;
WorkEntry = (PRTLP_WORK) RtlpAllocateTPHeap ( sizeof (RTLP_WORK), HEAP_ZERO_MEMORY) ;
if (! WorkEntry) { return STATUS_NO_MEMORY; }
if (NtCurrentTeb()->IsImpersonating) { Status = NtOpenThreadToken(NtCurrentThread(), MAXIMUM_ALLOWED, TRUE, &WorkEntry->ImpersonationToken); if (! NT_SUCCESS(Status)) { RtlpFreeTPHeap(WorkEntry); return Status; } } else { WorkEntry->ImpersonationToken = NULL; }
Status = RtlpThreadPoolGetActiveActivationContext(&WorkEntry->ActivationContext); if (!NT_SUCCESS(Status)) { if (Status == STATUS_SXS_THREAD_QUERIES_DISABLED) { WorkEntry->ActivationContext = INVALID_ACTIVATION_CONTEXT; Status = STATUS_SUCCESS; } else { if (WorkEntry->ImpersonationToken) { NtClose(WorkEntry->ImpersonationToken); } RtlpFreeTPHeap(WorkEntry); return Status; } }
// Increment the outstanding work request counter
NumWorkRequests++; if (Flags & WT_EXECUTELONGFUNCTION) { NumLongWorkRequests++; }
WorkEntry->Function = Function ; WorkEntry->Flags = Flags ;
if (Flags & WT_EXECUTEINPERSISTENTTHREAD) {
// Queue APC to timer thread
Status = NtQueueApcThread( TimerThreadHandle, (PPS_APC_ROUTINE)RtlpExecuteWorkerRequest, (PVOID) STATUS_SUCCESS, (PVOID) Context, (PVOID) WorkEntry ) ;
} else {
InterlockedIncrement(&NumQueuedWorkRequests);
Status = NtSetIoCompletion ( WorkerCompletionPort, RtlpExecuteWorkerRequest, (PVOID) WorkEntry, STATUS_SUCCESS, (ULONG_PTR)Context ); if (! NT_SUCCESS(Status)) { InterlockedDecrement(&NumQueuedWorkRequests); } }
if ( ! NT_SUCCESS(Status) ) { NumWorkRequests--; if (Flags & WT_EXECUTELONGFUNCTION) { NumLongWorkRequests--; }
if (WorkEntry->ActivationContext != INVALID_ACTIVATION_CONTEXT) RtlReleaseActivationContext(WorkEntry->ActivationContext);
if (WorkEntry->ImpersonationToken) { NtClose(WorkEntry->ImpersonationToken); }
RtlpFreeTPHeap( WorkEntry ) ; }
return Status ;}
NTSTATUSRtlQueueWorkItem( IN WORKERCALLBACKFUNC Function, IN PVOID Context, IN ULONG Flags )
/*++
Routine Description:
This routine queues up the request to be executed in a worker thread.
Arguments:
Function - Routine that is called by the worker thread
Context - Opaque pointer passed in as an argument to WorkerProc
Flags - Can be:
WT_EXECUTEINIOTHREAD - Specifies that the WorkerProc should be invoked by a thread that is never destroyed when there are pending IO requests. This can be used by threads that invoke I/O and/or schedule APCs.
The below flag can also be set: WT_EXECUTELONGFUNCTION - Specifies that the function might block for a long duration.
Return Value:
STATUS_SUCCESS - Queued successfully.
STATUS_NO_MEMORY - There was not sufficient heap to perform the requested operation.
--*/
{ ULONG Threshold ; ULONG CurrentTickCount ; NTSTATUS Status = STATUS_SUCCESS ;
if (LdrpShutdownInProgress) { return STATUS_UNSUCCESSFUL; }
// Make sure the worker thread pool is initialized
if (CompletedWorkerInitialization != 1) {
Status = RtlpInitializeWorkerThreadPool () ;
if (! NT_SUCCESS(Status) ) return Status ; }
// Take lock for the global worker thread pool
RtlEnterCriticalSection (&WorkerCriticalSection) ;
if (Flags&0xffff0000) { MaxThreads = (Flags & 0xffff0000)>>16; }
if (NEEDS_IO_THREAD(Flags)) {
//
// execute in IO Worker thread
//
ULONG NumEffIOWorkerThreads = NumIOWorkerThreads > NumLongIOWorkRequests ? NumIOWorkerThreads - NumLongIOWorkRequests : 0; ULONG ThreadCreationDampingTime = NumIOWorkerThreads < NEW_THREAD_THRESHOLD ? THREAD_CREATION_DAMPING_TIME1 : THREAD_CREATION_DAMPING_TIME2 ;
if (NumEffIOWorkerThreads && PersistentIOTCB && (Flags&WT_EXECUTELONGFUNCTION)) NumEffIOWorkerThreads -- ;
// Check if we need to grow I/O worker thread pool
Threshold = (NumEffIOWorkerThreads < MAX_WORKER_THREADS ? NEW_THREAD_THRESHOLD * NumEffIOWorkerThreads : 0xffffffff) ;
if (LastThreadCreationTickCount > NtGetTickCount()) LastThreadCreationTickCount = NtGetTickCount() ;
if (NumEffIOWorkerThreads == 0 || ((NumIOWorkRequests - NumLongIOWorkRequests > Threshold) && (LastThreadCreationTickCount + ThreadCreationDampingTime < NtGetTickCount()))) {
// Grow the IO worker thread pool
Status = RtlpStartIOWorkerThread () ;
}
if (NT_SUCCESS(Status)) {
// Queue the work request
Status = RtlpQueueIOWorkerRequest (Function, Context, Flags) ; }
} else {
//
// execute in regular worker thread
//
ULONG NumEffWorkerThreads = NumWorkerThreads > NumLongWorkRequests ? NumWorkerThreads - NumLongWorkRequests : 0; ULONG ThreadCreationDampingTime = NumWorkerThreads < NEW_THREAD_THRESHOLD ? THREAD_CREATION_DAMPING_TIME1 : (NumWorkerThreads < 30 ? THREAD_CREATION_DAMPING_TIME2 : NumWorkerThreads << 13);
// if io completion set, then have 1 more thread
if (NumMinWorkerThreads && NumEffWorkerThreads) NumEffWorkerThreads -- ;
// Check if we need to grow worker thread pool
Threshold = (NumWorkerThreads < MAX_WORKER_THREADS ? (NumEffWorkerThreads < 7 ? NumEffWorkerThreads*NumEffWorkerThreads : ((NumEffWorkerThreads<40) ? NEW_THREAD_THRESHOLD * NumEffWorkerThreads : NEW_THREAD_THRESHOLD2 * NumEffWorkerThreads)) : 0xffffffff) ;
if (LastThreadCreationTickCount > NtGetTickCount()) LastThreadCreationTickCount = NtGetTickCount() ;
if (NumEffWorkerThreads == 0 || ( (NumWorkRequests - NumLongWorkRequests >= Threshold) && (LastThreadCreationTickCount + ThreadCreationDampingTime < NtGetTickCount()))) { // Grow the worker thread pool
if (NumWorkerThreads<MaxThreads) { Status = RtlpStartWorkerThread () ;
} }
// Queue the work request
if (NT_SUCCESS(Status)) {
Status = RtlpQueueWorkerRequest (Function, Context, Flags) ; }
}
// Release lock on the worker thread pool
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
return Status ;}
NTSTATUSRtlpWorkerCleanup( VOID ){ PLIST_ENTRY Node; ULONG i; HANDLE TmpHandle; BOOLEAN Cleanup;
IS_COMPONENT_INITIALIZED( StartedWorkerInitialization, CompletedWorkerInitialization, Cleanup ) ;
if ( Cleanup ) {
RtlEnterCriticalSection (&WorkerCriticalSection) ;
if ( (NumWorkRequests != 0) || (NumIOWorkRequests != 0) ) {
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
return STATUS_UNSUCCESSFUL ; }
// queue a cleanup for each worker thread
for (i = 0 ; i < NumWorkerThreads ; i ++ ) {
NtSetIoCompletion ( WorkerCompletionPort, RtlpThreadCleanup, NULL, STATUS_SUCCESS, 0 ); }
// queue an apc to cleanup all IO worker threads
for (Node = IOWorkerThreads.Flink ; Node != &IOWorkerThreads ; Node = Node->Flink ) { PRTLP_IOWORKER_TCB ThreadCB ;
ThreadCB = CONTAINING_RECORD (Node, RTLP_IOWORKER_TCB, List) ; RemoveEntryList( &ThreadCB->List) ; TmpHandle = ThreadCB->ThreadHandle ;
NtQueueApcThread( ThreadCB->ThreadHandle, (PPS_APC_ROUTINE)RtlpThreadCleanup, NULL, NULL, NULL );
NtClose( TmpHandle ) ; }
NumWorkerThreads = NumIOWorkerThreads = 0 ;
RtlLeaveCriticalSection (&WorkerCriticalSection) ;
}
return STATUS_SUCCESS;}
NTSTATUSRtlpThreadPoolGetActiveActivationContext( PACTIVATION_CONTEXT* ActivationContext ){ ACTIVATION_CONTEXT_BASIC_INFORMATION ActivationContextInfo = {0}; NTSTATUS Status = STATUS_SUCCESS;
ASSERT(ActivationContext != NULL); *ActivationContext = NULL;
Status = RtlQueryInformationActivationContext( RTL_QUERY_INFORMATION_ACTIVATION_CONTEXT_FLAG_USE_ACTIVE_ACTIVATION_CONTEXT, NULL, 0, ActivationContextBasicInformation, &ActivationContextInfo, sizeof(ActivationContextInfo), NULL); if (!NT_SUCCESS(Status)) { goto Exit; } if ((ActivationContextInfo.Flags & ACTIVATION_CONTEXT_FLAG_NO_INHERIT) != 0) { RtlReleaseActivationContext(ActivationContextInfo.ActivationContext); ActivationContextInfo.ActivationContext = NULL; // fall through
} *ActivationContext = ActivationContextInfo.ActivationContext; Status = STATUS_SUCCESS;Exit: return Status;}
NTSTATUSRtlpAcquireWorker(ULONG Flags){ NTSTATUS Status = STATUS_SUCCESS; if (CompletedWorkerInitialization != 1) { Status = RtlpInitializeWorkerThreadPool () ;
if (! NT_SUCCESS(Status) ) return Status ; }
if (NEEDS_IO_THREAD(Flags)) { RtlEnterCriticalSection(&WorkerCriticalSection); InterlockedIncrement(&NumFutureIOWorkItems); if (NumIOWorkerThreads == 0) { Status = RtlpStartIOWorkerThread(); } RtlLeaveCriticalSection(&WorkerCriticalSection); } else { RtlEnterCriticalSection(&WorkerCriticalSection); InterlockedIncrement(&NumFutureWorkItems); if (NumWorkerThreads == 0) { Status = RtlpStartWorkerThread(); } RtlLeaveCriticalSection(&WorkerCriticalSection); }
return Status;}
VOIDRtlpReleaseWorker(ULONG Flags){ if (NEEDS_IO_THREAD(Flags)) { ASSERT(NumFutureIOWorkItems > 0); InterlockedDecrement(&NumFutureIOWorkItems); } else { ASSERT(NumFutureWorkItems > 0); InterlockedDecrement(&NumFutureWorkItems); }}
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