minix/lib/libsys/sched_start.c

   1 #include "syslib.h"
   2 #include <assert.h>
   3 #include <machine/archtypes.h>
   4 #include <minix/timers.h>
   5 #include <minix/sched.h>
   6 #include <string.h>
   7
   8 /*===========================================================================*
   9  *                              sched_inherit                                *
  10  *===========================================================================*/
  11 int sched_inherit(endpoint_t scheduler_e,
  12         endpoint_t schedulee_e, endpoint_t parent_e, unsigned maxprio,
  13         endpoint_t *newscheduler_e)
  14 {
  15         int rv;
  16         message m;
  17
  18         assert(_ENDPOINT_P(scheduler_e) >= 0);
  19         assert(_ENDPOINT_P(schedulee_e) >= 0);
  20         assert(_ENDPOINT_P(parent_e) >= 0);
  21         assert(maxprio < NR_SCHED_QUEUES);
  22         assert(newscheduler_e);
  23
  24         memset(&m, 0, sizeof(m));
  25         m.m_lsys_sched_scheduling_start.endpoint        = schedulee_e;
  26         m.m_lsys_sched_scheduling_start.parent          = parent_e;
  27         m.m_lsys_sched_scheduling_start.maxprio         = maxprio;
  28
  29         /* Send the request to the scheduler */
  30         if ((rv = _taskcall(scheduler_e, SCHEDULING_INHERIT, &m))) {
  31                 return rv;
  32         }
  33
  34         /* Store the process' scheduler. Note that this might not be the
  35          * scheduler we sent the SCHEDULING_INHERIT message to. That scheduler
  36          * might have forwarded the scheduling message on to another scheduler
  37          * before returning the message.
  38          */
  39         *newscheduler_e = m.m_sched_lsys_scheduling_start.scheduler;
  40         return (OK);
  41 }
  42
  43 /*===========================================================================*
  44  *                              sched_start                                  *
  45  *===========================================================================*/
  46 int sched_start(endpoint_t scheduler_e,
  47                         endpoint_t schedulee_e,
  48                         endpoint_t parent_e,
  49                         int maxprio,
  50                         int quantum,
  51                         int cpu,
  52                         endpoint_t *newscheduler_e)
  53 {
  54         int rv;
  55         message m;
  56
  57         /* No scheduler given? We are done. */
  58         if(scheduler_e == NONE) {
  59                 return OK;
  60         }
  61
  62         assert(_ENDPOINT_P(schedulee_e) >= 0);
  63         assert(_ENDPOINT_P(parent_e) >= 0);
  64         assert(maxprio >= 0);
  65         assert(maxprio < NR_SCHED_QUEUES);
  66         assert(quantum > 0);
  67         assert(newscheduler_e);
  68
  69         /* The KERNEL must schedule this process. */
  70         if(scheduler_e == KERNEL) {
  71                 if ((rv = sys_schedctl(SCHEDCTL_FLAG_KERNEL,
  72                         schedulee_e, maxprio, quantum, cpu)) != OK) {
  73                         return rv;
  74                 }
  75                 *newscheduler_e = scheduler_e;
  76                 return OK;
  77         }
  78
  79         /* A user-space scheduler must schedule this process. */
  80         memset(&m, 0, sizeof(m));
  81         m.m_lsys_sched_scheduling_start.endpoint        = schedulee_e;
  82         m.m_lsys_sched_scheduling_start.parent          = parent_e;
  83         m.m_lsys_sched_scheduling_start.maxprio         = maxprio;
  84         m.m_lsys_sched_scheduling_start.quantum         = quantum;
  85
  86         /* Send the request to the scheduler */
  87         if ((rv = _taskcall(scheduler_e, SCHEDULING_START, &m))) {
  88                 return rv;
  89         }
  90
  91         /* Store the process' scheduler. Note that this might not be the
  92          * scheduler we sent the SCHEDULING_START message to. That scheduler
  93          * might have forwarded the scheduling message on to another scheduler
  94          * before returning the message.
  95          */
  96         *newscheduler_e = m.m_sched_lsys_scheduling_start.scheduler;
  97         return (OK);
  98 }