rom/exec/service.c

   1 /*
   2     Copyright © 1995-2017, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: exec.library's internal service task. Performs memory management according
   6           to task scheduler's requests.
   7     Lang: english
   8 */
   9
  10 #include <exec/execbase.h>
  11 #include <exec/tasks.h>
  12 #include <aros/libcall.h>
  13 #include <proto/exec.h>
  14
  15 #include "exec_intern.h"
  16 #include "exec_util.h"
  17 #include "exec_debug.h"
  18
  19 void ServiceTask(struct ExecBase *SysBase)
  20 {
  21 #if defined(__AROSEXEC_SMP__)
  22     struct Task *serviceTask;
  23 #endif
  24     struct Task *task;
  25     struct MemList *mb, *mbnext;
  26     BOOL taskRequeue;
  27     DINIT("ServiceTask: Started up");
  28
  29 #if defined(__AROSEXEC_SMP__)
  30     serviceTask = FindTask(NULL);
  31     DINIT("ServiceTask: task @ 0x%p", serviceTask);
  32 #endif
  33
  34     do
  35     { /* forever */
  36
  37
  38         while ((task = (struct Task *)GetMsg(PrivExecBase(SysBase)->ServicePort)))
  39         {
  40             DREMTASK("ServiceTask: Request for Task 0x%p, State %08X\n", task, task->tc_State);
  41             taskRequeue = TRUE;
  42
  43             /*
  44              * If we ever need to use TSS here, we'll need to explicitly check its size here.
  45              * However we don't need this, because we never call so high-level libraries.
  46              * So, currently we ignore this.
  47              */
  48
  49             switch (task->tc_State)
  50             {
  51 #if defined(__AROSEXEC_SMP__)
  52             case TS_TOMBSTONED:
  53                 if (!(PrivExecBase(SysBase)->IntFlags & EXECF_CPUAffinity) || (GetIntETask(serviceTask)->iet_CpuNumber== (IPTR)task->tc_UserData))
  54                 {
  55                     DREMTASK("ServiceTask: Task is running on this CPU (%03u)\n", task->tc_UserData);
  56                     taskRequeue = FALSE;
  57                 }
  58 #endif
  59             case TS_REMOVED:
  60                 if (taskRequeue)
  61                 {
  62                     DREMTASK("ServiceTask: Requeueing request for Task 0x%p <%s> (State:%08x)", task, task->tc_Node.ln_Name, task->tc_State);
  63                     InternalPutMsg(PrivExecBase(SysBase)->ServicePort,
  64                         (struct Message *)task, SysBase);
  65                     break;
  66                 }
  67             case TS_INVALID:
  68                 DREMTASK("ServiceTask: Removal request for Task 0x%p <%s> (State:%08x)", task, task->tc_Node.ln_Name, task->tc_State);
  69
  70                 // TODO: Make sure the task has terminated..
  71                 task->tc_State = TS_INVALID;
  72
  73                 /*
  74                  * Note tc_MemEntry list is part of the task structure which
  75                  * usually is also placed in tc_MemEntry. MungWall_Check()
  76                  * will fill freed memory and destroy our list while we are
  77                  * iterating or the freed memory including our list could be
  78                  * reused by some other task. We take special care of this by
  79                  * resetting ln_Succ of the last node to NULL. This way we
  80                  * avoid getting back to our List structure.
  81                  */
  82                 task->tc_MemEntry.lh_TailPred->ln_Succ = NULL;
  83
  84                 for (mb = (struct MemList *)task->tc_MemEntry.lh_Head; mb; mb = mbnext)
  85                 {
  86                     /* Free one MemList node */
  87                     mbnext = (struct MemList *)mb->ml_Node.ln_Succ;
  88
  89                     DREMTASK("ServiceTask: Freeing MemList 0x%p", mb);
  90                     FreeEntry(mb);
  91                 }
  92                 break;
  93
  94             default:
  95                 if ((task->tc_Node.ln_Type == NT_TASK) || (task->tc_Node.ln_Type == NT_PROCESS))
  96                 {
  97                     /* FIXME: Add fault handling here. Perhaps kernel-level GURU. */
  98                     DREMTASK("ServiceTask: Task 0x%p <%s> not in servicable state!\n", task, task->tc_Node.ln_Name);
  99                     DREMTASK("ServiceTask: State = %08X\n", task->tc_State);
 100
 101                     /*
 102                      * Mark the task as ready to run again. Move it back to TaskReady list.
 103                      */
 104 #if !defined(EXEC_REMTASK_NEEDSSWITCH)
 105                     task->tc_State = TS_READY;
 106                     Enqueue(&SysBase->TaskReady, &task->tc_Node);
 107 #else
 108                     krnSysCallReschedTask(task, TS_READY);
 109 #endif
 110                 }
 111                 else
 112                 {
 113                     DREMTASK("ServiceTask: Called with something that is not a task??\n");
 114                 }
 115                 break;
 116             }
 117         }
 118
 119         WaitPort(PrivExecBase(SysBase)->ServicePort);
 120     } while(1);
 121 }