reactos/ntoskrnl/ex/work.c

   1 /*
   2  * COPYRIGHT:          See COPYING in the top level directory
   3  * PROJECT:            ReactOS kernel
   4  * FILE:               mkernel/kernel/work.c
   5  * PURPOSE:            Manage system work queues
   6  * PROGRAMMER:         David Welch (welch@mcmail.com)
   7  * REVISION HISTORY:
   8  *             29/06/98: Created
   9  */
  10
  11 /* INCLUDES ******************************************************************/
  12
  13 #include <ddk/ntddk.h>
  14
  15 #include <internal/debug.h>
  16
  17 /* TYPES *********************************************************************/
  18
  19 typedef struct
  20 {
  21    /*
  22     * PURPOSE: Head of the list of waiting work items
  23     */
  24    LIST_ENTRY Head;
  25
  26    /*
  27     * PURPOSE: Sychronize access to the access
  28     */
  29    KSPIN_LOCK Lock;
  30
  31    /*
  32     * PURPOSE: Worker threads with nothing to do wait on this event
  33     */
  34    KEVENT Busy;
  35
  36    /*
  37     * PURPOSE: Thread associated with work queue
  38     */
  39    HANDLE Thread;
  40 } WORK_QUEUE, *PWORK_QUEUE;
  41
  42 /* GLOBALS *******************************************************************/
  43
  44 /*
  45  * PURPOSE: Queue of items waiting to be processed at normal priority
  46  */
  47 WORK_QUEUE normal_work_queue = {{0,}};
  48
  49 #define WAIT_INTERVAL (0)
  50
  51 /* FUNCTIONS ****************************************************************/
  52
  53 static NTSTATUS ExWorkerThreadEntryPoint(PVOID context)
  54 /*
  55  * FUNCTION: Entry point for a worker thread
  56  * ARGUMENTS:
  57  *         context = Parameters
  58  * RETURNS: Status
  59  * NOTE: To kill a worker thread you must queue an item whose callback
  60  * calls PsTerminateSystemThread
  61  */
  62 {
  63    PWORK_QUEUE param = (PWORK_QUEUE)context;
  64    PWORK_QUEUE_ITEM item;
  65    PLIST_ENTRY current;
  66
  67    while (1)
  68      {
  69         current = ExInterlockedRemoveHeadList(&param->Head,&param->Lock);
  70         if (current!=NULL)
  71           {
  72              item = CONTAINING_RECORD(current,WORK_QUEUE_ITEM,Entry);
  73              item->Routine(item->Context);
  74           }
  75         else
  76           {
  77              KeClearEvent(&param->Busy);
  78              KeWaitForSingleObject((PVOID)&param->Busy,Executive,KernelMode,
  79                                    FALSE,WAIT_INTERVAL);
  80           }
  81      };
  82 }
  83
  84 static VOID ExKillWorkerThreadCallback(PVOID Context)
  85 {
  86    PsTerminateSystemThread(STATUS_SUCCESS);
  87 }
  88
  89 void ExKillWorkerThreads(void)
  90 /*
  91  * FUNCTION: Kill all running worker threads in preparation for a shutdown
  92  */
  93 {
  94    WORK_QUEUE_ITEM item1;
  95
  96    ExInitializeWorkItem(&item1,ExKillWorkerThreadCallback,NULL);
  97    ExQueueWorkItem(&item1,DelayedWorkQueue);
  98 }
  99
 100 void ExInitializeWorkerThreads(void)
 101 {
 102    InitializeListHead(&normal_work_queue.Head);
 103    KeInitializeSpinLock(&normal_work_queue.Lock);
 104    KeInitializeEvent(&normal_work_queue.Busy,NotificationEvent,FALSE);
 105    PsCreateSystemThread(&normal_work_queue.Thread,THREAD_ALL_ACCESS,
 106                         NULL,NULL,NULL,ExWorkerThreadEntryPoint,
 107                         &normal_work_queue);
 108 }
 109
 110 VOID ExInitializeWorkItem(PWORK_QUEUE_ITEM Item,
 111                           PWORKER_THREAD_ROUTINE Routine,
 112                           PVOID Context)
 113 /*
 114  * FUNCTION: Initializes a work item to be processed by one of the system
 115  * worker threads
 116  * ARGUMENTS:
 117  *         Item = Pointer to the item to be initialized
 118  *         Routine = Routine to be called by the worker thread
 119  *         Context = Parameter to be passed to the callback
 120  */
 121 {
 122    ASSERT_IRQL(DISPATCH_LEVEL);
 123
 124    Item->Routine=Routine;
 125    Item->Context=Context;
 126    Item->Entry.Flink=NULL;
 127    Item->Entry.Blink=NULL;
 128 }
 129
 130 VOID ExQueueWorkItem(PWORK_QUEUE_ITEM WorkItem,
 131                      WORK_QUEUE_TYPE QueueType)
 132 /*
 133  * FUNCTION: Inserts a work item in a queue for one of the system worker
 134  * threads to process
 135  * ARGUMENTS:
 136  *        WorkItem = Item to insert
 137  *        QueueType = Queue to insert it in
 138  */
 139 {
 140    assert(WorkItem!=NULL);
 141    ASSERT_IRQL(DISPATCH_LEVEL);
 142
 143    /*
 144     * Insert the item in the appropiate queue and wake up any thread
 145     * waiting for something to do
 146     */
 147    switch(QueueType)
 148      {
 149       case DelayedWorkQueue:
 150         ExInterlockedInsertTailList(&normal_work_queue.Head,&(WorkItem->Entry),
 151                                     &normal_work_queue.Lock);
 152         KeSetEvent(&normal_work_queue.Busy,IO_NO_INCREMENT,FALSE);
 153         break;
 154      }
 155 }