void
ast_check(void)
{
register int mycpu;
register processor_t myprocessor;
register thread_t thread = current_thread();
spl_t s = splsched();
mp_disable_preemption();
mycpu = cpu_number();
/*
* Check processor state for ast conditions.
*/
myprocessor = cpu_to_processor(mycpu);
switch(myprocessor->state) {
case PROCESSOR_OFF_LINE:
case PROCESSOR_IDLE:
case PROCESSOR_DISPATCHING:
/*
* No ast.
*/
break;
#if NCPUS > 1
case PROCESSOR_ASSIGN:
case PROCESSOR_SHUTDOWN:
/*
* Need ast to force action thread onto processor.
*
* XXX Should check if action thread is already there.
*/
ast_on(mycpu, AST_BLOCK);
break;
#endif /* NCPUS > 1 */
case PROCESSOR_RUNNING:
case PROCESSOR_VIDLE:
/*
* Propagate thread ast to processor. If we already
* need an ast, don't look for more reasons.
*/
ast_propagate(current_act(), mycpu);
if (ast_needed(mycpu))
break;
/*
* Context switch check.
*/
if (csw_needed(thread, myprocessor)) {
ast_on(mycpu, (myprocessor->first_quantum ?
AST_BLOCK : AST_QUANTUM));
}
break;
default:
panic("ast_check: Bad processor state");
}
mp_enable_preemption();
splx(s);
}
void
ast_check(void)
{
int mycpu = cpu_number();
processor_t myprocessor;
thread_t thread = current_thread();
run_queue_t rq;
spl_t s = splsched();
/*
* Check processor state for ast conditions.
*/
myprocessor = cpu_to_processor(mycpu);
switch(myprocessor->state) {
case PROCESSOR_OFF_LINE:
case PROCESSOR_IDLE:
case PROCESSOR_DISPATCHING:
/*
* No ast.
*/
break;
#if NCPUS > 1
case PROCESSOR_ASSIGN:
case PROCESSOR_SHUTDOWN:
/*
* Need ast to force action thread onto processor.
*
* XXX Should check if action thread is already there.
*/
ast_on(mycpu, AST_BLOCK);
break;
#endif /* NCPUS > 1 */
case PROCESSOR_RUNNING:
/*
* Propagate thread ast to processor. If we already
* need an ast, don't look for more reasons.
*/
ast_propagate(thread, mycpu);
if (ast_needed(mycpu))
break;
/*
* Context switch check. The csw_needed macro isn't
* used here because the rq->low hint may be wrong,
* and fixing it here avoids an extra ast.
* First check the easy cases.
*/
if (thread->state & TH_SUSP || myprocessor->runq.count > 0) {
ast_on(mycpu, AST_BLOCK);
break;
}
/*
* Update lazy evaluated runq->low if only timesharing.
*/
#if MACH_FIXPRI
if (myprocessor->processor_set->policies & POLICY_FIXEDPRI) {
if (csw_needed(thread,myprocessor)) {
ast_on(mycpu, AST_BLOCK);
break;
}
else {
/*
* For fixed priority threads, set first_quantum
* so entire new quantum is used.
*/
if (thread->policy == POLICY_FIXEDPRI)
myprocessor->first_quantum = TRUE;
}
}
else {
#endif /* MACH_FIXPRI */
rq = &(myprocessor->processor_set->runq);
if (!(myprocessor->first_quantum) && (rq->count > 0)) {
queue_t q;
/*
* This is not the first quantum, and there may
* be something in the processor_set runq.
* Check whether low hint is accurate.
*/
q = rq->runq + *(volatile int *)&rq->low;
if (queue_empty(q)) {
int i;
/*
* Need to recheck and possibly update hint.
*/
simple_lock(&rq->lock);
q = rq->runq + rq->low;
if (rq->count > 0) {
for (i = rq->low; i < NRQS; i++) {
if(!(queue_empty(q)))
break;
q++;
}
rq->low = i;
}
simple_unlock(&rq->lock);
}
if (rq->low <= thread->sched_pri) {
ast_on(mycpu, AST_BLOCK);
break;
}
}
#if MACH_FIXPRI
}
#endif /* MACH_FIXPRI */
break;
default:
panic("ast_check: Bad processor state (cpu %d processor %08x) state: %d",
mycpu, myprocessor, myprocessor->state);
}
(void) splx(s);
}
