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Rewrite to remove dependence on rendezvous and its bizarre

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data structures.  Makes it easier to use pthreads too.
Still need to add code for non-pthreads systems.

Just a checkpoint to switch work to another machine.
This commit is contained in:
rsc 2004-09-17 00:38:29 +00:00
parent 984e353160
commit 06bb4ed20d
15 changed files with 205 additions and 218 deletions
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87
src/lib9/qlock.c
View file

@ -16,13 +16,15 @@ enum
Waking,
};
static ulong (*_rendezvousp)(ulong, ulong) = rendezvous;
static void (*procsleep)(_Procrend*) = _procsleep;
static void (*procwakeup)(_Procrend*) = _procwakeup;
/* this gets called by the thread library ONLY to get us to use its rendezvous */
void
_qlockinit(ulong (*r)(ulong, ulong))
_qlockinit(void (*sleep)(_Procrend*), void (*wakeup)(_Procrend*))
{
_rendezvousp = r;
procsleep = sleep;
procwakeup = wakeup;
}
/* find a free shared memory location to queue ourselves in */
@ -39,7 +41,7 @@ getqlp(void)
fprint(2, "qlock: out of qlp\n");
abort();
}
if(_tas(&(p->inuse)) == 0){
if(canlock(&p->inuse)){
ql.p = p;
p->next = nil;
break;
@ -70,13 +72,11 @@ qlock(QLock *q)
p->next = mp;
q->tail = mp;
mp->state = Queuing;
mp->rend.l = &q->lock;
_procsleep(&mp->rend);
unlock(&q->lock);
/* wait */
while((*_rendezvousp)((ulong)mp, 1) == ~0)
;
assert(mp->state == Waking);
mp->inuse = 0;
unlock(&mp->inuse);
}
void
@ -91,10 +91,9 @@ qunlock(QLock *q)
q->head = p->next;
if(q->head == nil)
q->tail = nil;
unlock(&q->lock);
p->state = Waking;
while((*_rendezvousp)((ulong)p, 0x12345) == ~0)
;
_procwakeup(&p->rend);
unlock(&q->lock);
return;
}
q->locked = 0;
@ -137,13 +136,11 @@ rlock(RWLock *q)
q->tail = mp;
mp->next = nil;
mp->state = QueuingR;
mp->rend.l = &q->lock;
_procsleep(&mp->rend);
unlock(&q->lock);
/* wait in kernel */
while((*_rendezvousp)((ulong)mp, 1) == ~0)
;
assert(mp->state == Waking);
mp->inuse = 0;
unlock(&mp->inuse);
}
int
@ -181,12 +178,11 @@ runlock(RWLock *q)
if(q->head == 0)
q->tail = 0;
q->writer = 1;
unlock(&q->lock);
/* wakeup waiter */
p->state = Waking;
while((*_rendezvousp)((ulong)p, 0) == ~0)
;
_procwakeup(&p->rend);
unlock(&q->lock);
}
void
@ -212,13 +208,13 @@ wlock(RWLock *q)
q->tail = mp;
mp->next = nil;
mp->state = QueuingW;
unlock(&q->lock);
/* wait in kernel */
while((*_rendezvousp)((ulong)mp, 1) == ~0)
;
mp->rend.l = &q->lock;
_procsleep(&mp->rend);
unlock(&q->lock);
assert(mp->state == Waking);
mp->inuse = 0;
unlock(&mp->inuse);
}
int
@ -256,10 +252,9 @@ wunlock(RWLock *q)
q->head = p->next;
if(q->head == nil)
q->tail = nil;
unlock(&q->lock);
p->state = Waking;
while((*_rendezvousp)((ulong)p, 0) == ~0)
;
_procwakeup(&p->rend);
unlock(&q->lock);
return;
}
@ -274,8 +269,7 @@ wunlock(RWLock *q)
q->head = p->next;
q->readers++;
p->state = Waking;
while((*_rendezvousp)((ulong)p, 0) == ~0)
;
_procwakeup(&p->rend);
}
if(q->head == nil)
q->tail = nil;
@ -315,20 +309,17 @@ rsleep(Rendez *r)
r->l->head = t->next;
if(r->l->head == nil)
r->l->tail = nil;
unlock(&r->l->lock);
t->state = Waking;
while((*_rendezvousp)((ulong)t, 0x12345) == ~0)
;
}else{
_procwakeup(&t->rend);
}else
r->l->locked = 0;
unlock(&r->l->lock);
}
/* wait for a wakeup */
while((*_rendezvousp)((ulong)me, 0x23456) == ~0)
;
me->rend.l = &r->l->lock;
_procsleep(&me->rend);
assert(me->state == Waking);
me->inuse = 0;
unlock(&me->inuse);
if(!r->l->locked){
fprint(2, "rsleep: not locked after wakeup\n");
abort();
@ -384,3 +375,23 @@ rwakeupall(Rendez *r)
;
return i;
}
void
_procsleep(_Procrend *rend)
{
//print("sleep %p %d\n", rend, getpid());
pthread_cond_init(&rend->cond, 0);
rend->asleep = 1;
while(rend->asleep)
pthread_cond_wait(&rend->cond, &rend->l->mutex);
pthread_cond_destroy(&rend->cond);
}
void
_procwakeup(_Procrend *rend)
{
//print("wakeup %p\n", rend);
rend->asleep = 0;
pthread_cond_signal(&rend->cond);
}