kernel/system/do_schedctl.c

   1 #include "kernel/system.h"
   2 #include <minix/endpoint.h>
   3
   4 /*===========================================================================*
   5  *                                do_schedctl                        *
   6  *===========================================================================*/
   7 int do_schedctl(struct proc * caller, message * m_ptr)
   8 {
   9         struct proc *p;
  10         unsigned flags;
  11         int priority, quantum, cpu;
  12         int proc_nr;
  13         int r;
  14
  15         /* check parameter validity */
  16         flags = (unsigned) m_ptr->SCHEDCTL_FLAGS;
  17         if (flags & ~SCHEDCTL_FLAG_KERNEL) {
  18                 printf("do_schedctl: flags 0x%x invalid, caller=%d\n",
  19                         flags, caller - proc);
  20                 return EINVAL;
  21         }
  22
  23         if (!isokendpt(m_ptr->SCHEDCTL_ENDPOINT, &proc_nr))
  24                 return EINVAL;
  25
  26         p = proc_addr(proc_nr);
  27
  28         if ((flags & SCHEDCTL_FLAG_KERNEL) == SCHEDCTL_FLAG_KERNEL) {
  29                 /* the kernel becomes the scheduler and starts
  30                  * scheduling the process.
  31                  */
  32                 priority = (int) m_ptr->SCHEDCTL_PRIORITY;
  33                 quantum = (int) m_ptr->SCHEDCTL_QUANTUM;
  34                 cpu = (int) m_ptr->SCHEDCTL_CPU;
  35
  36                 /* Try to schedule the process. */
  37                 if((r = sched_proc(p, priority, quantum, cpu) != OK))
  38                         return r;
  39                 p->p_scheduler = NULL;
  40         } else {
  41                 /* the caller becomes the scheduler */
  42                 p->p_scheduler = caller;
  43         }
  44
  45         return(OK);
  46 }