reactos/ntoskrnl/mm/pager.c

   1 /* $Id: pager.c,v 1.18 2004/08/15 16:39:08 chorns Exp $
   2  *
   3  * COPYRIGHT:    See COPYING in the top level directory
   4  * PROJECT:      ReactOS kernel
   5  * FILE:         ntoskrnl/mm/pager.c
   6  * PURPOSE:      Moves infrequently used data out of memory
   7  * PROGRAMMER:   David Welch (welch@cwcom.net)
   8  * UPDATE HISTORY:
   9  *               27/05/98: Created
  10  */
  11
  12 /* INCLUDES ****************************************************************/
  13
  14 #include <ntoskrnl.h>
  15 #define NDEBUG
  16 #include <internal/debug.h>
  17
  18 /* GLOBALS *******************************************************************/
  19
  20 #if 0
  21 static HANDLE PagerThreadHandle;
  22 static CLIENT_ID PagerThreadId;
  23 static KEVENT PagerThreadEvent;
  24 static BOOLEAN PagerThreadShouldTerminate;
  25 static ULONG PagerThreadWorkCount;
  26 #endif
  27
  28 /* FUNCTIONS *****************************************************************/
  29
  30 #if 0
  31 BOOLEAN
  32 MiIsPagerThread(VOID)
  33 {
  34    return(PsGetCurrentThreadId() == PagerThreadId.UniqueThread);
  35 }
  36
  37 VOID
  38 MiStartPagerThread(VOID)
  39 {
  40    ULONG WasWorking;
  41
  42    WasWorking = InterlockedIncrement(&PagerThreadWorkCount);
  43    if (WasWorking == 1)
  44    {
  45       KeSetEvent(&PagerThreadEvent, IO_NO_INCREMENT, FALSE);
  46    }
  47 }
  48
  49 VOID
  50 MiStopPagerThread(VOID)
  51 {
  52    (VOID)InterlockedDecrement(&PagerThreadWorkCount);
  53 }
  54
  55 static NTSTATUS STDCALL
  56 MmPagerThreadMain(PVOID Ignored)
  57 {
  58    NTSTATUS Status;
  59
  60    for(;;)
  61    {
  62       /* Wake for a low memory situation or a terminate request. */
  63       Status = KeWaitForSingleObject(&PagerThreadEvent,
  64                                      0,
  65                                      KernelMode,
  66                                      FALSE,
  67                                      NULL);
  68       if (!NT_SUCCESS(Status))
  69       {
  70          DbgPrint("PagerThread: Wait failed\n");
  71          KEBUGCHECK(0);
  72       }
  73       if (PagerThreadShouldTerminate)
  74       {
  75          DbgPrint("PagerThread: Terminating\n");
  76          return(STATUS_SUCCESS);
  77       }
  78       do
  79       {
  80          /* Try and make some memory available to the system. */
  81          MmRebalanceMemoryConsumers();
  82       }
  83       while(PagerThreadWorkCount > 0);
  84    }
  85 }
  86
  87 NTSTATUS MmInitPagerThread(VOID)
  88 {
  89    NTSTATUS Status;
  90
  91    PagerThreadShouldTerminate = FALSE;
  92    PagerThreadWorkCount = 0;
  93    KeInitializeEvent(&PagerThreadEvent,
  94                      SynchronizationEvent,
  95                      FALSE);
  96
  97    Status = PsCreateSystemThread(&PagerThreadHandle,
  98                                  THREAD_ALL_ACCESS,
  99                                  NULL,
 100                                  NULL,
 101                                  &PagerThreadId,
 102                                  (PKSTART_ROUTINE) MmPagerThreadMain,
 103                                  NULL);
 104    if (!NT_SUCCESS(Status))
 105    {
 106       return(Status);
 107    }
 108
 109    return(STATUS_SUCCESS);
 110 }
 111 #endif