mirror of https://github.com/tongzx/nt5src
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
513 lines
14 KiB
513 lines
14 KiB
/*++
|
|
|
|
Copyright (C) 2001 Microsoft Corporation
|
|
|
|
Module Name:
|
|
|
|
THRPOOL.H
|
|
|
|
Abstract:
|
|
|
|
General purpose thread pool.
|
|
|
|
History:
|
|
|
|
raymcc 25-Feb-99 Created
|
|
|
|
--*/
|
|
|
|
|
|
/*
|
|
(1) Flexible thread pool size. Starts at zero and only creates threads
|
|
as required.
|
|
(2) Threads wait to be reused and if not reused within the alloted time,
|
|
they self-terminate. Therefore, the thread pool drops to zero
|
|
within the specified timeout if no activity occurs.
|
|
(3) To avoid creating a lot of threads quickly, a request will attempt
|
|
to wait a small amount of time for a thread to free up before requesting
|
|
a new thread creation.
|
|
*/
|
|
|
|
#include "precomp.h"
|
|
#include <stdio.h>
|
|
#include <assert.h>
|
|
|
|
#include "corepol.h"
|
|
#include <thrpool.h>
|
|
|
|
|
|
#define THREAD_STACK_SIZE 0x2000 /* 8K */
|
|
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::CThreadPool
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
CThreadPool::CThreadPool(
|
|
DWORD dwMsMaxIdleBeforeDie,
|
|
LONG lIdleThreadLimit,
|
|
LONG lMaxThreads
|
|
)
|
|
{
|
|
m_dwMsMaxIdle = dwMsMaxIdleBeforeDie;
|
|
m_lMaxThreads = lMaxThreads;
|
|
m_lIdleThreadLimit = lIdleThreadLimit;
|
|
|
|
m_lTotalThreads = 0;
|
|
m_lIdleThreads = 0;
|
|
|
|
m_hReleaseThread = CreateEvent(0, 0, 0, 0);
|
|
m_hBeginRendezvous = CreateEvent(0, 0, 0, 0);
|
|
m_hParmXfer = CreateEvent(0, 0, 0, 0);
|
|
m_hEndRendezvous = CreateEvent(0, 0, 0, 0);
|
|
|
|
InitializeCriticalSection(&m_cs_dispatch);
|
|
InitializeCriticalSection(&m_cs_pool);
|
|
|
|
m_bPendingRequest = false;
|
|
m_bShutdown = false;
|
|
|
|
m_pXferUserParms = 0;
|
|
m_pXferUserProc = 0;
|
|
m_pXferReturnCode = 0;
|
|
m_pXferElapsedTime = 0;
|
|
}
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::~CThreadPool
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
CThreadPool::~CThreadPool()
|
|
{
|
|
bool bRes = Shutdown(); // Let all threads terminate
|
|
|
|
|
|
if (bRes)
|
|
{
|
|
CloseHandle(m_hReleaseThread);
|
|
CloseHandle(m_hBeginRendezvous);
|
|
CloseHandle(m_hParmXfer);
|
|
CloseHandle(m_hEndRendezvous);
|
|
|
|
DeleteCriticalSection(&m_cs_dispatch);
|
|
DeleteCriticalSection(&m_cs_pool);
|
|
}
|
|
// Else we will have to leak, since all the threads didn't shut down.
|
|
}
|
|
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::_ThreadEntry()
|
|
//
|
|
// Win32 entry point, which wraps and call the per-object entry point.
|
|
// We do this because Win32 cannot easily call an entry point in a C++
|
|
// instance unless we use various weird calling convention override
|
|
// tricks, which I don't remember right now. :)
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
DWORD WINAPI CThreadPool::_ThreadEntry(LPVOID pArg)
|
|
{
|
|
CThreadPool *pThis = (CThreadPool *) pArg;
|
|
pThis->Pool();
|
|
return 0; // Not used
|
|
}
|
|
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::Pool
|
|
//
|
|
// The basic pool is implemented here. All active threads remain in this
|
|
// loop. Any threads which get too old waiting for work are allowed to
|
|
// retire. New threads are created from the DispatchThread() member.
|
|
//
|
|
// Note that the <m_lTotalThreads> and <m_lIdleThreads> are not part
|
|
// of the algorithm; they are simply there for statistical purposes.
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
void CThreadPool::Pool()
|
|
{
|
|
InterlockedIncrement(&m_lTotalThreads);
|
|
|
|
// Pool.
|
|
// =====
|
|
|
|
for (;;)
|
|
{
|
|
if (m_bShutdown)
|
|
break;
|
|
|
|
if (m_lIdleThreadLimit != -1 && m_lIdleThreads > m_lIdleThreadLimit)
|
|
break;
|
|
|
|
// Wait for either the thread to be idle or else until a new
|
|
// request causes it to be released.
|
|
// =========================================================
|
|
|
|
InterlockedIncrement(&m_lIdleThreads);
|
|
|
|
DWORD dwRes = WaitForSingleObject(m_hReleaseThread, m_dwMsMaxIdle);
|
|
|
|
// We don't know why the thread was released. Maybe it was tired
|
|
// of waiting or maybe the user is shutting down our little operation.
|
|
// ===================================================================
|
|
|
|
if (dwRes == WAIT_TIMEOUT || m_bShutdown)
|
|
{
|
|
InterlockedDecrement(&m_lIdleThreads);
|
|
break;
|
|
}
|
|
|
|
// If here, we now enter the pool critical section and attempt
|
|
// to enter into a synchronized rendezvous with the dispacher.
|
|
// ============================================================
|
|
|
|
EnterCriticalSection(&m_cs_pool);
|
|
|
|
if (m_bPendingRequest)
|
|
{
|
|
InterlockedDecrement(&m_lIdleThreads);
|
|
|
|
SetEvent(m_hBeginRendezvous);
|
|
WaitForSingleObject(m_hParmXfer, INFINITE);
|
|
|
|
// Copy the parameters that the user specified in
|
|
// DispatchThread(). We cannot be here unless
|
|
// DispatchThread() signaled us.
|
|
// ==============================================
|
|
|
|
LPVOID pUserArg = m_pXferUserParms;
|
|
LPTHREAD_START_ROUTINE pUserEntry = m_pXferUserProc;
|
|
LPDWORD pElapsed = m_pXferElapsedTime;
|
|
LPDWORD pRetVal = m_pXferReturnCode;
|
|
HANDLE hCompleted = m_hXferThreadCompleted;
|
|
m_bPendingRequest = false;
|
|
|
|
// No longer in 'request' mode, so a new dispatch can occur.
|
|
// Note that the user's parms are safely in local variables.
|
|
// Allow further dispatches to occur.
|
|
// ========================================================
|
|
|
|
SetEvent(m_hEndRendezvous);
|
|
|
|
LeaveCriticalSection(&m_cs_pool);
|
|
|
|
// If user wants elapsed time, record start time.
|
|
// ==============================================
|
|
|
|
DWORD dwStart = 0;
|
|
if (m_pXferElapsedTime)
|
|
dwStart = GetCurrentTime();
|
|
|
|
// Call user's entry point.
|
|
// ========================
|
|
|
|
DWORD dwResToRet = pUserEntry(pUserArg);
|
|
|
|
// If user wants return value, forward it.
|
|
// =======================================
|
|
|
|
if (pRetVal)
|
|
*pRetVal = dwResToRet;
|
|
|
|
// If user wants elapsed time, record stop time
|
|
// and forward elapsed time.
|
|
// ============================================
|
|
|
|
if (m_pXferElapsedTime)
|
|
*m_pXferElapsedTime = GetCurrentTime() - dwStart;
|
|
|
|
// If user wants event signaled, do it.
|
|
// ====================================
|
|
|
|
if (hCompleted)
|
|
SetEvent(hCompleted);
|
|
|
|
}
|
|
|
|
// If here, somehow the event got signaled and nobody wanted
|
|
// the thread. This could occur if somebody executed Shutdown()
|
|
// and then Restart() before Shutdown() was finished.
|
|
// Simply return to top of loop.
|
|
// =============================================================
|
|
|
|
else
|
|
{
|
|
LeaveCriticalSection(&m_cs_pool);
|
|
InterlockedDecrement(&m_lIdleThreads);
|
|
}
|
|
}
|
|
|
|
InterlockedDecrement(&m_lTotalThreads);
|
|
// printf("---Thread Ending--- 0x%X\n", GetCurrentThreadId());
|
|
}
|
|
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::Shutdown
|
|
//
|
|
// Alas, the pool is doomed and must be drained. Inform each thread of
|
|
// its fate.
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
bool CThreadPool::Shutdown(DWORD dwMaxWait)
|
|
{
|
|
m_bShutdown = true;
|
|
m_bPendingRequest = false;
|
|
|
|
DWORD dwStart = GetCurrentTime();
|
|
|
|
while (m_lTotalThreads && m_bShutdown) // No need to protect this
|
|
{
|
|
SetEvent(m_hReleaseThread); // Allow thread to realize it is doomed
|
|
if (GetCurrentTime() - dwStart > dwMaxWait)
|
|
break;
|
|
Sleep(10);
|
|
}
|
|
|
|
if (m_lTotalThreads == 0)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::Restart
|
|
//
|
|
// Allow a thread pool to get back into business again.
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
bool CThreadPool::Restart()
|
|
{
|
|
m_bShutdown = false;
|
|
return true;
|
|
}
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::CreateNewThread
|
|
//
|
|
// Helper to create a new thread.
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
bool CThreadPool::CreateNewThread()
|
|
{
|
|
DWORD dwId;
|
|
|
|
HANDLE hThread = CreateThread(
|
|
0, // Security
|
|
THREAD_STACK_SIZE, // 8k stack
|
|
_ThreadEntry, // Thread proc address
|
|
LPVOID(this), // Thread parm
|
|
0, // Flags
|
|
&dwId
|
|
);
|
|
|
|
if (hThread == NULL)
|
|
return false;
|
|
|
|
// printf("--Created Thread 0x%X\n", dwId);
|
|
|
|
CloseHandle(hThread);
|
|
return true;
|
|
}
|
|
|
|
|
|
//***************************************************************************
|
|
//
|
|
// CThreadPool::DispatchThread
|
|
//
|
|
// Called by the user to dispatch a thread to an entry point.
|
|
//
|
|
// Returns:
|
|
// NoError -- Success
|
|
// ExceededPool -- No threads available within the timeout.
|
|
// Shutdown -- Thread pool is being shut down
|
|
// ThreadCreationFailure -- Couldn't create a thread.
|
|
//
|
|
//***************************************************************************
|
|
// ok
|
|
|
|
|
|
int CThreadPool::DispatchThread(
|
|
IN DWORD dwMaxPreferredWait,
|
|
IN DWORD dwMaxWaitBeforeFail,
|
|
IN LPTHREAD_START_ROUTINE pEntry,
|
|
IN LPVOID pArg,
|
|
IN DWORD *pdwReturnCode,
|
|
IN DWORD *pdwElapsedTime,
|
|
IN HANDLE hThreadCompleted
|
|
)
|
|
{
|
|
DWORD dwRes;
|
|
|
|
// Don't allow new requests during a shutdown.
|
|
// ===========================================
|
|
|
|
if (m_bShutdown)
|
|
return ShutdownInProgress;
|
|
|
|
|
|
// Serialize all access to thread acquisition.
|
|
// ===========================================
|
|
|
|
EnterCriticalSection(&m_cs_dispatch);
|
|
|
|
// If zero threads, create one.
|
|
// ============================
|
|
|
|
if (m_lTotalThreads == 0)
|
|
{
|
|
if (CreateNewThread() != true)
|
|
{
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
return ThreadCreationFailure;
|
|
}
|
|
}
|
|
|
|
|
|
// Flag for the pool to look at to determine
|
|
// if a dispatch is in progress.
|
|
// =========================================
|
|
|
|
m_bPendingRequest = true;
|
|
|
|
// Release at least one thread. If there aren't any
|
|
// available, this is harmless. Likewise, if this
|
|
// releases threads which don't in fact become acquired
|
|
// by this dispatch, again it is harmless.
|
|
// ====================================================
|
|
|
|
SetEvent(m_hReleaseThread);
|
|
|
|
// We now try to rendevous with a thread within the
|
|
// dwMaxPreferredWait time by waiting for a 'thready ready'
|
|
// event from the thread pool. If no thread responds,
|
|
// because they are busy, we will timeout.
|
|
// ========================================================
|
|
|
|
dwRes = WaitForSingleObject(m_hBeginRendezvous, dwMaxPreferredWait);
|
|
|
|
if (dwRes == WAIT_OBJECT_0)
|
|
{
|
|
// We are now in a synchronized rendevous with the thread pool.
|
|
// Next, make the interthread parameter transfer.
|
|
// ============================================================
|
|
|
|
m_pXferUserParms = pArg;
|
|
m_pXferUserProc = pEntry;
|
|
m_pXferElapsedTime = pdwElapsedTime;
|
|
m_pXferReturnCode = pdwReturnCode;
|
|
m_hXferThreadCompleted = hThreadCompleted;
|
|
|
|
m_bPendingRequest = false; // No longer needed
|
|
|
|
// Now, release the thread pool thread to grab the parameters.
|
|
// ===========================================================
|
|
|
|
SetEvent(m_hParmXfer);
|
|
|
|
WaitForSingleObject(m_hEndRendezvous, INFINITE);
|
|
|
|
LeaveCriticalSection(&m_cs_dispatch); // Allow more dispatches
|
|
|
|
return NoError;
|
|
}
|
|
|
|
if (m_bShutdown)
|
|
{
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
return ShutdownInProgress;
|
|
}
|
|
|
|
// If here, we didn't acquire a thread. Let's create another one.
|
|
// If, in the meantime, the event shows up anyway (and we simply
|
|
// didn't wait long enough!), then we ended up with another thread.
|
|
// So what? If one is good, two is better.
|
|
// ================================================================
|
|
|
|
if (m_lMaxThreads == -1 || (m_lTotalThreads < m_lMaxThreads))
|
|
{
|
|
if (CreateNewThread() != true)
|
|
{
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
return ThreadCreationFailure;
|
|
}
|
|
}
|
|
|
|
if (m_bShutdown)
|
|
{
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
return ShutdownInProgress;
|
|
}
|
|
|
|
// Now, wait for that same old event, indicating we have begun
|
|
// a synchronized rendevous with the thread pool.
|
|
// ============================================================
|
|
|
|
dwRes = WaitForSingleObject(m_hBeginRendezvous, dwMaxWaitBeforeFail);
|
|
|
|
if (m_bShutdown)
|
|
{
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
return ShutdownInProgress;
|
|
}
|
|
|
|
if (dwRes == WAIT_OBJECT_0)
|
|
{
|
|
// We are now in a synchronized rendevous with the thread pool.
|
|
// Next, make the interthread parameter transfer.
|
|
// ============================================================
|
|
|
|
m_pXferUserParms = pArg;
|
|
m_pXferUserProc = pEntry;
|
|
m_pXferElapsedTime = pdwElapsedTime;
|
|
m_pXferReturnCode = pdwReturnCode;
|
|
m_hXferThreadCompleted = hThreadCompleted;
|
|
|
|
m_bPendingRequest = false; // No longer needed
|
|
|
|
// Now, release the thread pool thread to grab the parameters.
|
|
// ===========================================================
|
|
|
|
SetEvent(m_hParmXfer);
|
|
|
|
WaitForSingleObject(m_hEndRendezvous, INFINITE);
|
|
|
|
LeaveCriticalSection(&m_cs_dispatch); // Allow more dispatches
|
|
|
|
return NoError;
|
|
}
|
|
|
|
// If here, we simply ran out of time. If in the meantime
|
|
// the event gets signaled, it will benefit any new thread coming
|
|
// in looking for a request!
|
|
// ==============================================================
|
|
|
|
m_bPendingRequest = false; // We may be too late, but it looks good anyway.
|
|
|
|
LeaveCriticalSection(&m_cs_dispatch);
|
|
|
|
return ExceededPool;
|
|
}
|
|
|
|
|