BOOLEAN PhpCreateWorkQueueThread(
_Inout_ PPH_WORK_QUEUE WorkQueue
)
{
HANDLE threadHandle;
// Make sure the structure doesn't get deleted while the thread is running.
if (!PhAcquireRundownProtection(&WorkQueue->RundownProtect))
return FALSE;
threadHandle = PhCreateThread(0, PhpWorkQueueThreadStart, WorkQueue);
if (threadHandle)
{
PHLIB_INC_STATISTIC(WqWorkQueueThreadsCreated);
WorkQueue->CurrentThreads++;
NtClose(threadHandle);
return TRUE;
}
else
{
PHLIB_INC_STATISTIC(WqWorkQueueThreadsCreateFailed);
PhReleaseRundownProtection(&WorkQueue->RundownProtect);
return FALSE;
}
}
NTSTATUS PhpWorkQueueThreadStart(
_In_ PVOID Parameter
)
{
PPH_WORK_QUEUE workQueue = (PPH_WORK_QUEUE)Parameter;
while (TRUE)
{
NTSTATUS status;
HANDLE semaphoreHandle;
LARGE_INTEGER timeout;
PPH_WORK_QUEUE_ITEM workQueueItem = NULL;
// Check if we have more threads than the limit.
if (workQueue->CurrentThreads > workQueue->MaximumThreads)
{
BOOLEAN terminate = FALSE;
// Lock and re-check.
PhAcquireQueuedLockExclusive(&workQueue->StateLock);
// Check the minimum as well.
if (workQueue->CurrentThreads > workQueue->MaximumThreads &&
workQueue->CurrentThreads > workQueue->MinimumThreads)
{
workQueue->CurrentThreads--;
terminate = TRUE;
}
PhReleaseQueuedLockExclusive(&workQueue->StateLock);
if (terminate)
break;
}
semaphoreHandle = PhpGetSemaphoreWorkQueue(workQueue);
if (!workQueue->Terminating)
{
// Wait for work.
status = NtWaitForSingleObject(
semaphoreHandle,
FALSE,
PhTimeoutFromMilliseconds(&timeout, workQueue->NoWorkTimeout)
);
}
else
{
status = STATUS_UNSUCCESSFUL;
}
if (status == STATUS_WAIT_0 && !workQueue->Terminating)
{
PLIST_ENTRY listEntry;
// Dequeue the work item.
PhAcquireQueuedLockExclusive(&workQueue->QueueLock);
listEntry = RemoveHeadList(&workQueue->QueueListHead);
if (IsListEmpty(&workQueue->QueueListHead))
PhPulseCondition(&workQueue->QueueEmptyCondition);
PhReleaseQueuedLockExclusive(&workQueue->QueueLock);
// Make sure we got work.
if (listEntry != &workQueue->QueueListHead)
{
workQueueItem = CONTAINING_RECORD(listEntry, PH_WORK_QUEUE_ITEM, ListEntry);
PhpExecuteWorkQueueItem(workQueueItem);
_InterlockedDecrement(&workQueue->BusyCount);
PhpDestroyWorkQueueItem(workQueueItem);
}
}
else
{
BOOLEAN terminate = FALSE;
// No work arrived before the timeout passed, or we are terminating, or some error occurred.
// Terminate the thread.
PhAcquireQueuedLockExclusive(&workQueue->StateLock);
if (workQueue->Terminating || workQueue->CurrentThreads > workQueue->MinimumThreads)
{
workQueue->CurrentThreads--;
terminate = TRUE;
}
PhReleaseQueuedLockExclusive(&workQueue->StateLock);
if (terminate)
break;
}
}
PhReleaseRundownProtection(&workQueue->RundownProtect);
return STATUS_SUCCESS;
}
NTSTATUS PhpWorkQueueThreadStart(
__in PVOID Parameter
)
{
PPH_WORK_QUEUE workQueue = (PPH_WORK_QUEUE)Parameter;
while (TRUE)
{
NTSTATUS status;
LARGE_INTEGER timeout;
PPH_WORK_QUEUE_ITEM workQueueItem = NULL;
// Check if we have more threads than the limit.
if (workQueue->CurrentThreads > workQueue->MaximumThreads)
{
BOOLEAN terminate = FALSE;
// Lock and re-check.
PhAcquireQueuedLockExclusive(&workQueue->StateLock);
// Check the minimum as well.
if (
workQueue->CurrentThreads > workQueue->MaximumThreads &&
workQueue->CurrentThreads > workQueue->MinimumThreads
)
{
workQueue->CurrentThreads--;
terminate = TRUE;
}
PhReleaseQueuedLockExclusive(&workQueue->StateLock);
if (terminate)
break;
}
// Wait for work.
status = NtWaitForSingleObject(
workQueue->SemaphoreHandle,
FALSE,
PhTimeoutFromMilliseconds(&timeout, workQueue->NoWorkTimeout)
);
if (workQueue->Terminating)
{
// The work queue is being deleted.
PhAcquireQueuedLockExclusive(&workQueue->StateLock);
workQueue->CurrentThreads--;
PhReleaseQueuedLockExclusive(&workQueue->StateLock);
break;
}
if (status == STATUS_WAIT_0)
{
PLIST_ENTRY listEntry;
// Dequeue the work item.
PhAcquireQueuedLockExclusive(&workQueue->QueueLock);
listEntry = RemoveHeadList(&workQueue->QueueListHead);
PhReleaseQueuedLockExclusive(&workQueue->QueueLock);
// Make sure we got work.
if (listEntry != &workQueue->QueueListHead)
{
workQueueItem = CONTAINING_RECORD(listEntry, PH_WORK_QUEUE_ITEM, ListEntry);
_InterlockedIncrement(&workQueue->BusyThreads);
PhpExecuteWorkQueueItem(workQueueItem);
_InterlockedDecrement(&workQueue->BusyThreads);
PhFreeToFreeList(&PhWorkQueueItemFreeList, workQueueItem);
}
}
else
{
BOOLEAN terminate = FALSE;
// No work arrived before the timeout passed (or some error occurred).
// Terminate the thread.
PhAcquireQueuedLockExclusive(&workQueue->StateLock);
// Check the minimum.
if (workQueue->CurrentThreads > workQueue->MinimumThreads)
{
workQueue->CurrentThreads--;
terminate = TRUE;
}
PhReleaseQueuedLockExclusive(&workQueue->StateLock);
if (terminate)
break;
}
}
PhReleaseRundownProtection(&workQueue->RundownProtect);
return STATUS_SUCCESS;
}