/*!
* Deactivate thread because:
* 1. higher priority thread becomes active
* 2. this thread time slice is expired
* 3. this thread blocks on some queue
*/
static int rr_thread_deactivate ( kthread_t *kthread )
{
/* Get current time and recalculate remainder */
time_t t;
kthread_sched_data_t *tsched = kthread_get_sched_param ( kthread );
ksched_t *gsched = ksched_get ( tsched->sched_policy );
if (tsched->params.rr.remainder.sec + tsched->params.rr.remainder.nsec)
{
/*
* "slice interrupted"
* recalculate remainder
*/
k_get_time ( &t );
time_sub ( &tsched->params.rr.slice_end, &t );
tsched->params.rr.remainder = tsched->params.rr.slice_end;
if ( kthread_is_ready ( kthread ) )
{
/* is remainder too small or not? */
if ( time_cmp ( &tsched->params.rr.remainder,
&gsched->params.rr.threshold ) <= 0 )
{
kthread_move_to_ready ( kthread, LAST );
}
else {
kthread_move_to_ready ( kthread, FIRST );
}
}
}
/* else = remainder is zero, thread is already enqueued in ready queue*/
return 0;
}
/*! Start time slice for thread (or countinue interrupted) */
static int rr_thread_activate ( kthread_t *kthread )
{
kthread_sched_data_t *tsched = kthread_get_sched_param ( kthread );
ksched_t *gsched = ksched_get ( tsched->sched_policy );
/* check remainder if needs to be replenished */
if ( time_cmp ( &tsched->params.rr.remainder,
&gsched->params.rr.threshold ) <= 0 )
{
time_add ( &tsched->params.rr.remainder,
&gsched->params.rr.time_slice );
}
/* Get current time and store it */
k_get_time ( &tsched->params.rr.slice_start );
/* When to wake up? */
tsched->params.rr.slice_end = tsched->params.rr.slice_start;
time_add ( &tsched->params.rr.slice_end, &tsched->params.rr.remainder );
/* Set alarm for remainder time */
gsched->params.rr.alarm.exp_time = tsched->params.rr.slice_end;
gsched->params.rr.alarm.param = kthread;
k_alarm_set ( gsched->params.rr.rr_alarm, &gsched->params.rr.alarm );
return 0;
}
static int rr_set_sched_parameters ( int sched_policy, sched_t *params )
{
ksched_t *gsched = ksched_get ( sched_policy );
gsched->params.rr.time_slice = params->rr.time_slice;
return 0;
}
/*! Add thread to RR scheduler (give him initial time slice) */
static int rr_thread_add ( kthread_t *kthread )
{
kthread_sched_data_t *tsched = kthread_get_sched_param ( kthread );
ksched_t *gsched = ksched_get ( tsched->sched_policy );
tsched->params.rr.remainder = gsched->params.rr.time_slice;
return 0;
}
static int edf_thread_remove ( kthread_t *kthread )
{
kthread_sched_data_t *tsched = kthread_get_sched_param ( kthread );
ksched_t *gsched = ksched_get ( tsched->sched_policy );
if ( gsched->params.edf.active == kthread )
gsched->params.edf.active = NULL;
if ( tsched->params.edf.edf_period_alarm )
{
k_alarm_remove ( tsched->params.edf.edf_period_alarm );
tsched->params.edf.edf_period_alarm = NULL;
}
tsched->sched_policy = SCHED_FIFO;
k_edf_schedule ();
return 0;
}
static int k_edf_schedule ()
{
kthread_t *first, *next, *edf_active;
kthread_sched_data_t *sch_first, *sch_next;
ksched_t *gsched = ksched_get ( SCHED_EDF );
int retval = 0;
edf_active = gsched->params.edf.active;
first = kthreadq_get ( &gsched->params.edf.ready );
LOG( DEBUG, "%x [active]", edf_active );
LOG( DEBUG, "%x [first]", first );
//LOG( DEBUG, "%x [next]", next );
if ( !first )
return 0; /* no threads in edf.ready queue, edf.active unch. */
if ( edf_active )
{
next = first;
first = edf_active;
LOG( DEBUG, "%x [next]", kthreadq_get_next ( next ) );
}
else {
next = kthreadq_get_next ( first );
LOG( DEBUG, "%x [next]", next );
}
while ( first && next )
{
sch_first = kthread_get_sched_param ( first );
sch_next = kthread_get_sched_param ( next );
if ( time_cmp ( &sch_first->params.edf.active_deadline,
&sch_next->params.edf.active_deadline ) > 0 )
{
first = next;
}
next = kthreadq_get_next ( next );
}
if ( first && first != edf_active )
{
next = kthreadq_remove ( &gsched->params.edf.ready, first );
LOG ( DEBUG, "%x removed, %x is now first", next, kthreadq_get ( &gsched->params.edf.ready ) );
if ( edf_active )
{
LOG( DEBUG, "%x=>%x [EDF_SCHED_PREEMPT]",
edf_active, first );
/*
* change active EDF thread:
* -remove it from active/ready list
* -put it into edf.ready list
*/
if ( kthread_is_ready (edf_active) )
{
if ( !kthread_is_active (edf_active) )
{
kthread_remove_from_ready (edf_active);
/*
* set "deactivated" flag, don't need
* another call to "edf_schedule"
*/
}
else {
kthread_get_sched_param (edf_active)
->activated = 0;
}
kthread_enqueue ( edf_active,
&gsched->params.edf.ready );
}
/* else = thread is blocked - leave it there */
}
gsched->params.edf.active = first;
LOG( DEBUG, "%x [new active]", first );
kthread_move_to_ready ( first, LAST );
retval = 1;
}
return retval;
}
static int edf_set_thread_sched_parameters (kthread_t *kthread, sched_t *params)
{
time_t now;
alarm_t alarm;
kthread_sched_data_t *tsched = kthread_get_sched_param ( kthread );
ksched_t *gsched = ksched_get ( SCHED_EDF );
if ( gsched->params.edf.active == kthread )
gsched->params.edf.active = NULL;
k_get_time ( &now );
if ( params->edf.flags & EDF_SET )
{
/*LOG( DEBUG, "%x [SET]", kthread ); */
tsched->params.edf.period = params->edf.period;
tsched->params.edf.relative_deadline = params->edf.deadline;
tsched->params.edf.flags = params->edf.flags;
/* set periodic alarm */
tsched->params.edf.next_run = now;
time_add ( &tsched->params.edf.next_run, ¶ms->edf.period );
edf_arm_deadline ( kthread );
edf_arm_period ( kthread );
/*
* adjust "next_run" and "deadline" for "0" period
* - first "edf_wait" will set correct values for first period
*/
tsched->params.edf.next_run = now;
time_sub ( &tsched->params.edf.next_run, ¶ms->edf.period );
tsched->params.edf.active_deadline = now;
time_add ( &tsched->params.edf.active_deadline,
¶ms->edf.deadline );
}
else if ( params->edf.flags & EDF_WAIT )
{
if ( edf_check_deadline ( kthread ) )
return -1;
/* set times for next period */
if ( time_cmp ( &now, &tsched->params.edf.next_run ) > 0 )
{
time_add ( &tsched->params.edf.next_run,
&tsched->params.edf.period );
tsched->params.edf.active_deadline = tsched->params.edf.next_run;
time_add ( &tsched->params.edf.active_deadline,
&tsched->params.edf.relative_deadline );
if ( kthread == gsched->params.edf.active )
gsched->params.edf.active = NULL;
/* set (separate) alarm for deadline */
alarm.action = edf_deadline_timer;
alarm.param = kthread;
alarm.flags = 0;
alarm.period.sec = alarm.period.nsec = 0;
alarm.exp_time = tsched->params.edf.active_deadline;
k_alarm_set ( tsched->params.edf.edf_deadline_alarm, &alarm );
}
/* is task ready for execution, or must wait until next period */
if ( time_cmp ( &tsched->params.edf.next_run, &now ) > 0 )
{
/* wait till "next_run" */
LOG( DEBUG, "%x [EDF WAIT]", kthread );
kthread_enqueue ( kthread, &gsched->params.edf.wait );
kthreads_schedule (); /* will call edf_schedule() */
}
else {
/* "next_run" has already come,
* activate task => move it to "EDF ready tasks"
*/
LOG( DEBUG, "%x [EDF READY]", kthread );
LOG( DEBUG, "%x [1st READY]", kthreadq_get ( &gsched->params.edf.ready ) );
kthread_enqueue ( kthread, &gsched->params.edf.ready );
kthreads_schedule (); /* will call edf_schedule() */
}
}
else if ( params->edf.flags & EDF_EXIT )
{
if ( kthread == gsched->params.edf.active )
gsched->params.edf.active = NULL;
//LOG( DEBUG, "%x [EXIT]", kthread );
if ( edf_check_deadline ( kthread ) )
{
LOG( DEBUG, "%x [EXIT-error]", kthread );
return -1;
}
LOG( DEBUG, "%x [EXIT-normal]", kthread );
if ( tsched->params.edf.edf_period_alarm )
k_alarm_remove ( tsched->params.edf.edf_period_alarm );
if ( tsched->params.edf.edf_deadline_alarm )
k_alarm_remove ( tsched->params.edf.edf_deadline_alarm );
tsched->sched_policy = SCHED_FIFO;
LOG( DEBUG, "%x [EXIT]", kthread );
if ( k_edf_schedule () )
{
LOG( DEBUG, "%x [EXIT]", kthread );
kthreads_schedule (); /* will NOT call edf_schedule() */
}
LOG( DEBUG, "%x [EXIT]", kthread );
}
return 0;
}
