Rewrite to remove dependence on rendezvous and its bizarre

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.

src/libthread/rendez.c

@@ -1,104 +1,38 @@
 #include "threadimpl.h"
 
-Rgrp _threadrgrp;
-static int isdirty;
 int _threadhighnrendez;
 int _threadnrendez;
-static int nrendez;
 
-static ulong
-finish(Thread *t, ulong val)
+void
+_threadsleep(_Procrend *r)
 {
-	ulong ret;
+	Thread *t;
 
-	ret = t->rendval;
-	t->rendval = val;
+	t = _threadgetproc()->thread;
+	r->arg = t;
+	t->nextstate = Rendezvous;
+	t->inrendez = 1;
+	unlock(r->l);
+	_sched();
+	t->inrendez = 0;
+	lock(r->l);
+}
+
+void
+_threadwakeup(_Procrend *r)
+{
+	Thread *t;
+
+	t = r->arg;
 	while(t->state == Running)
 		sleep(0);
 	lock(&t->proc->lock);
-	if(t->state == Rendezvous){	/* not always true: might be Dead */
-		t->state = Ready;
-		_threadready(t);
+	if(t->state == Dead){
+		unlock(&t->proc->lock);
+		return;
 	}
+	assert(t->state == Rendezvous && t->inrendez);
+	t->state = Ready;
+	_threadready(t);
 	unlock(&t->proc->lock);
-	return ret;
-}
-
-ulong
-_threadrendezvous(ulong tag, ulong val)
-{
-	ulong ret;
-	Thread *t, **l;
-
-	lock(&_threadrgrp.lock);
-_threadnrendez++;
-	l = &_threadrgrp.hash[tag%nelem(_threadrgrp.hash)];
-	for(t=*l; t; l=&t->rendhash, t=*l){
-		if(t->rendtag==tag){
-			_threaddebug(DBGREND, "Rendezvous with thread %d.%d", t->proc->pid, t->id);
-			*l = t->rendhash;
-			ret = finish(t, val);
-			--nrendez;
-			unlock(&_threadrgrp.lock);
-			return ret;
-		}
-	}
-
-	/* Going to sleep here. */
-	t = _threadgetproc()->thread;
-	t->rendbreak = 0;
-	t->inrendez = 1;
-	t->rendtag = tag;
-	t->rendval = val;
-	t->rendhash = *l;
-	*l = t;
-	++nrendez;
-	if(nrendez > _threadhighnrendez)
-		_threadhighnrendez = nrendez;
-	_threaddebug(DBGREND, "Rendezvous for tag %lud (m=%d)", t->rendtag, t->moribund);
-	unlock(&_threadrgrp.lock);
-	t->nextstate = Rendezvous;
-	_sched();
-	t->inrendez = 0;
-	_threaddebug(DBGREND, "Woke after rendezvous; val is %lud", t->rendval);
-	return t->rendval;
-}
-
-/*
- * This is called while holding _threadpq.lock and p->lock,
- * so we can't lock _threadrgrp.lock.  Instead our caller has 
- * to call _threadbreakrendez after dropping those locks.
- */
-void
-_threadflagrendez(Thread *t)
-{
-	t->rendbreak = 1;
-	isdirty = 1;
-}
-
-void
-_threadbreakrendez(void)
-{
-	int i;
-	Thread *t, **l;
-
-	if(isdirty == 0)
-		return;
-	lock(&_threadrgrp.lock);
-	if(isdirty == 0){
-		unlock(&_threadrgrp.lock);
-		return;
-	}
-	isdirty = 0;
-	for(i=0; i<nelem(_threadrgrp.hash); i++){
-		l = &_threadrgrp.hash[i];
-		for(t=*l; t; t=*l){
-			if(t->rendbreak){
-				*l = t->rendhash;
-				finish(t, ~0);
-			}else
-				 l=&t->rendhash;
-		}
-	}
-	unlock(&_threadrgrp.lock);
 }