plan9port/src/libthread/rendez.c
rsc 912fba95e7 Changes for Mac OS X. Most important is stack sizes in samterm,
which were completely bogus.  (Libthread used to ignore them but
not anymore.  Maybe we really should ignore them, but that breaks
Venti, which needs *really* big stacks.)
2003-11-24 22:39:06 +00:00

104 lines
2 KiB
C

#include "threadimpl.h"
Rgrp _threadrgrp;
static int isdirty;
int _threadhighnrendez;
int _threadnrendez;
static int nrendez;
static ulong
finish(Thread *t, ulong val)
{
ulong ret;
ret = t->rendval;
t->rendval = val;
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);
}
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);
}