/*
* uthread_setprio
*
* Changes the priority of the indicated thread. Note that if the thread
* is in the UT_RUNNABLE state (it's runnable but not on cpu) you should
* change the list it's waiting on so the effect of this call is
* immediate.
*/
void
uthread_setprio(uthread_id_t id, int prio)
{
uthread_t* thread_to_change = &uthreads[id];
if(thread_to_change->ut_state == UT_RUNNABLE){
int previous_prio = thread_to_change->ut_prio;
thread_to_change->ut_prio = prio;
utqueue_remove(&runq_table[previous_prio], thread_to_change);
utqueue_enqueue(&runq_table[prio], thread_to_change);
}
else{
//change directly
thread_to_change->ut_prio = prio;
}
return;
}
/*
* uthread_block
*
* Put the current thread to sleep, pending an appropriate call to
* uthread_wake().
*/
void
uthread_block(void)
{
/* Already waiting? deadlock */
if (ut_curthr->ut_state == UT_WAIT)
{
uthread_switch();
}
/* If the current thread is on cpu, then do context switch */
if (ut_curthr->ut_state == UT_ON_CPU)
{
ut_curthr->ut_state = UT_WAIT;
uthread_switch();
}
/* If the current thread is in the queue, remove it from the queue */
else if (ut_curthr->ut_state == UT_RUNNABLE)
{
ut_curthr->ut_state = UT_WAIT;
utqueue_remove(&runq_table[ut_curthr->ut_prio], ut_curthr);
}
}
/*
* uthread_setprio
*
* Changes the priority of the indicated thread.
* param id: the uthread id
* param prio: the priority to be set
*/
int
uthread_setprio(uthread_id_t id, int prio)
{
/* If prio is invalid */
if (prio < 0 || prio > UTH_MAXPRIO)
{
ut_curthr->ut_errno = EINVAL;
return EINVAL;
}
/* Invalid thread id */
if (id < 0 || id >= UTH_MAX_UTHREADS ||
uthreads[id].ut_state == UT_NO_STATE ||
uthreads[id].ut_state == UT_ZOMBIE)
{
ut_curthr->ut_errno = ESRCH;
return ESRCH;
}
/* If the current state is runnable */
if (uthreads[id].ut_state == UT_RUNNABLE)
{
if (uthreads[id].ut_link.l_prev != NULL &&
uthreads[id].ut_link.l_next != NULL)
utqueue_remove(&runq_table[uthreads[id].ut_prio], &uthreads[id]);
uthreads[id].ut_prio = prio;
utqueue_enqueue(&runq_table[prio], &uthreads[id]);
}
else
{
/* If it is waiting or on CPU, just set the priority */
/* Because it's not in the queue! */
uthreads[id].ut_prio = prio;
}
return 0;
}
