wine/dlls/ntdll/threadpool.c
2007-03-17 20:03:57 +01:00

221 lines
6.5 KiB
C

/*
* Thread pooling
*
* Copyright (c) 2006 Robert Shearman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include "config.h"
#include "wine/port.h"
#include <stdarg.h>
#include <limits.h>
#define NONAMELESSUNION
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "winternl.h"
#include "wine/debug.h"
#include "wine/list.h"
#include "ntdll_misc.h"
WINE_DEFAULT_DEBUG_CHANNEL(threadpool);
#define WORKER_TIMEOUT 30000 /* 30 seconds */
static LONG num_workers;
static LONG num_work_items;
static LONG num_busy_workers;
static struct list work_item_list = LIST_INIT(work_item_list);
static HANDLE work_item_event;
static RTL_CRITICAL_SECTION threadpool_cs;
static RTL_CRITICAL_SECTION_DEBUG critsect_debug =
{
0, 0, &threadpool_cs,
{ &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
0, 0, { (DWORD_PTR)(__FILE__ ": threadpool_cs") }
};
static RTL_CRITICAL_SECTION threadpool_cs = { &critsect_debug, -1, 0, 0, 0, 0 };
struct work_item
{
struct list entry;
PRTL_WORK_ITEM_ROUTINE function;
PVOID context;
};
static inline LONG interlocked_inc( PLONG dest )
{
return interlocked_xchg_add( (int *)dest, 1 ) + 1;
}
static inline LONG interlocked_dec( PLONG dest )
{
return interlocked_xchg_add( (int *)dest, -1 ) - 1;
}
static void WINAPI worker_thread_proc(void * param)
{
interlocked_inc(&num_workers);
/* free the work item memory sooner to reduce memory usage */
while (TRUE)
{
if (num_work_items > 0)
{
struct list *item;
RtlEnterCriticalSection(&threadpool_cs);
item = list_head(&work_item_list);
if (item)
{
struct work_item *work_item_ptr = LIST_ENTRY(item, struct work_item, entry);
struct work_item work_item;
list_remove(&work_item_ptr->entry);
interlocked_dec(&num_work_items);
RtlLeaveCriticalSection(&threadpool_cs);
work_item = *work_item_ptr;
RtlFreeHeap(GetProcessHeap(), 0, work_item_ptr);
TRACE("executing %p(%p)\n", work_item.function, work_item.context);
interlocked_inc(&num_busy_workers);
/* do the work */
work_item.function(work_item.context);
interlocked_dec(&num_busy_workers);
}
else
RtlLeaveCriticalSection(&threadpool_cs);
}
else
{
NTSTATUS status;
LARGE_INTEGER timeout;
timeout.QuadPart = -(WORKER_TIMEOUT * (ULONGLONG)10000);
status = NtWaitForSingleObject(work_item_event, FALSE, &timeout);
if (status != STATUS_WAIT_0)
break;
}
}
interlocked_dec(&num_workers);
RtlExitUserThread(0);
/* never reached */
}
static NTSTATUS add_work_item_to_queue(struct work_item *work_item)
{
NTSTATUS status;
RtlEnterCriticalSection(&threadpool_cs);
list_add_tail(&work_item_list, &work_item->entry);
num_work_items++;
RtlLeaveCriticalSection(&threadpool_cs);
if (!work_item_event)
{
HANDLE sem;
status = NtCreateSemaphore(&sem, SEMAPHORE_ALL_ACCESS, NULL, 1, LONG_MAX);
if (interlocked_cmpxchg_ptr( (PVOID *)&work_item_event, (PVOID)sem, 0 ))
NtClose(sem); /* somebody beat us to it */
}
else
status = NtReleaseSemaphore(work_item_event, 1, NULL);
return status;
}
/***********************************************************************
* RtlQueueWorkItem (NTDLL.@)
*
* Queues a work item into a thread in the thread pool.
*
* PARAMS
* Function [I] Work function to execute.
* Context [I] Context to pass to the work function when it is executed.
* Flags [I] Flags. See notes.
*
* RETURNS
* Success: STATUS_SUCCESS.
* Failure: Any NTSTATUS code.
*
* NOTES
* Flags can be one or more of the following:
*|WT_EXECUTEDEFAULT - Executes the work item in a non-I/O worker thread.
*|WT_EXECUTEINIOTHREAD - Executes the work item in an I/O worker thread.
*|WT_EXECUTEINPERSISTENTTHREAD - Executes the work item in a thread that is persistent.
*|WT_EXECUTELONGFUNCTION - Hints that the execution can take a long time.
*|WT_TRANSFER_IMPERSONATION - Executes the function with the current access token.
*/
NTSTATUS WINAPI RtlQueueWorkItem(PRTL_WORK_ITEM_ROUTINE Function, PVOID Context, ULONG Flags)
{
HANDLE thread;
NTSTATUS status;
struct work_item *work_item = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(struct work_item));
if (!work_item)
return STATUS_NO_MEMORY;
work_item->function = Function;
work_item->context = Context;
if (Flags & ~WT_EXECUTELONGFUNCTION)
FIXME("Flags 0x%x not supported\n", Flags);
status = add_work_item_to_queue(work_item);
/* FIXME: tune this algorithm to not be as aggressive with creating threads
* if WT_EXECUTELONGFUNCTION isn't specified */
if ((status == STATUS_SUCCESS) &&
((num_workers == 0) || (num_workers == num_busy_workers)))
{
status = RtlCreateUserThread( GetCurrentProcess(), NULL, FALSE,
NULL, 0, 0,
worker_thread_proc, NULL, &thread, NULL );
if (status == STATUS_SUCCESS)
NtClose( thread );
/* NOTE: we don't care if we couldn't create the thread if there is at
* least one other available to process the request */
if ((num_workers > 0) && (status != STATUS_SUCCESS))
status = STATUS_SUCCESS;
}
if (status != STATUS_SUCCESS)
{
RtlEnterCriticalSection(&threadpool_cs);
interlocked_dec(&num_work_items);
list_remove(&work_item->entry);
RtlFreeHeap(GetProcessHeap(), 0, work_item);
RtlLeaveCriticalSection(&threadpool_cs);
return status;
}
return STATUS_SUCCESS;
}