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#include "threadimpl.h"
#include <signal.h>
//static Thread *runthread(Proc*);
static char *_psstate[] = {
"Dead",
"Running",
"Ready",
"Rendezvous",
};
static char*
psstate(int s)
{
if(s < 0 || s >= nelem(_psstate))
return "unknown";
return _psstate[s];
}
void
_schedinit(void *arg)
{
Proc *p;
Thread *t;
extern void ignusr1(void), _threaddie(int);
ignusr1();
signal(SIGTERM, _threaddie);
p = arg;
p->pid = _threadgetpid();
_threadsetproc(p);
while(_setlabel(&p->sched))
;
_threaddebug(DBGSCHED, "top of schedinit, _threadexitsallstatus=%p", _threadexitsallstatus);
if(_threadexitsallstatus)
exits(_threadexitsallstatus);
lock(&p->lock);
if((t=p->thread) != nil){
p->thread = nil;
if(t->moribund){
assert(t->moribund == 1);
t->state = Dead;
if(t->prevt)
t->prevt->nextt = t->nextt;
else
p->threads.head = t->nextt;
if(t->nextt)
t->nextt->prevt = t->prevt;
else
p->threads.tail = t->prevt;
unlock(&p->lock);
if(t->inrendez){
_threadflagrendez(t);
_threadbreakrendez();
}
_stackfree(t->stk);
free(t->cmdname);
free(t); /* XXX how do we know there are no references? */
t = nil;
_sched();
}
if(p->needexec){
t->ret = _schedexec(&p->exec);
p->needexec = 0;
}
if(p->newproc){
t->ret = _schedfork(p->newproc);
if(t->ret < 0){
//fprint(2, "_schedfork: %r\n");
abort();
}
p->newproc = nil;
}
t->state = t->nextstate;
if(t->state == Ready)
_threadready(t);
}
unlock(&p->lock);
_sched();
}
static inline Thread*
runthread(Proc *p)
{
Thread *t;
Tqueue *q;
if(p->nthreads==0)
return nil;
q = &p->ready;
lock(&p->readylock);
if(q->head == nil){
q->asleep = 1;
_threaddebug(DBGSCHED, "sleeping for more work");
unlock(&p->readylock);
while(rendezvous((ulong)q, 0) == ~0){
if(_threadexitsallstatus)
exits(_threadexitsallstatus);
}
/* lock picked up from _threadready */
}
t = q->head;
q->head = t->next;
unlock(&p->readylock);
return t;
}
void
_sched(void)
{
Proc *p;
Thread *t;
Resched:
p = _threadgetproc();
//fprint(2, "p %p\n", p);
if((t = p->thread) != nil){
if((ulong)&p < (ulong)t->stk){ /* stack overflow */
fprint(2, "stack overflow %lux %lux\n", (ulong)&p, (ulong)t->stk);
abort();
}
// _threaddebug(DBGSCHED, "pausing, state=%s set %p goto %p",
// psstate(t->state), &t->sched, &p->sched);
if(_setlabel(&t->sched)==0)
_gotolabel(&p->sched);
return;
}else{
t = runthread(p);
if(t == nil){
_threaddebug(DBGSCHED, "all threads gone; exiting");
_threaddelproc();
_schedexit(p);
}
// _threaddebug(DBGSCHED, "running %d.%d", t->proc->pid, t->id);
p->thread = t;
if(t->moribund){
_threaddebug(DBGSCHED, "%d.%d marked to die");
goto Resched;
}
t->state = Running;
t->nextstate = Ready;
_gotolabel(&t->sched);
}
}
long
threadstack(void)
{
Proc *p;
Thread *t;
p = _threadgetproc();
t = p->thread;
return (ulong)&p - (ulong)t->stk;
}
void
_threadready(Thread *t)
{
Tqueue *q;
assert(t->state == Ready);
_threaddebug(DBGSCHED, "readying %d.%d", t->proc->pid, t->id);
q = &t->proc->ready;
lock(&t->proc->readylock);
t->next = nil;
if(q->head==nil)
q->head = t;
else
q->tail->next = t;
q->tail = t;
if(q->asleep){
q->asleep = 0;
/* lock passes to runthread */
_threaddebug(DBGSCHED, "waking process %d", t->proc->pid);
while(rendezvous((ulong)q, 0) == ~0){
if(_threadexitsallstatus)
exits(_threadexitsallstatus);
}
}else
unlock(&t->proc->readylock);
}
void
yield(void)
{
_sched();
}
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