Continue switching library over to pthreads when possible.

Tprimes works on Linux 2.6.  You can only have 128 procs
though.

1 files changed, 31 insertions, 168 deletions

diff --git a/src/lib9/rendez-signal.c b/src/lib9/rendez-signal.c
index 5709dd76..e2abc3d3 100644
--- a/src/lib9/rendez-signal.c
+++ b/src/lib9/rendez-signal.c
@@ -1,58 +1,9 @@
-/*
-     NAME
-          rendezvous - user level process synchronization
-
-     SYNOPSIS
-          ulong rendezvous(ulong tag, ulong value)
-
-     DESCRIPTION
-          The rendezvous system call allows two processes to synchro-
-          nize and exchange a value.  In conjunction with the shared
-          memory system calls (see segattach(2) and fork(2)), it
-          enables parallel programs to control their scheduling.
-
-          Two processes wishing to synchronize call rendezvous with a
-          common tag, typically an address in memory they share.  One
-          process will arrive at the rendezvous first; it suspends
-          execution until a second arrives.  When a second process
-          meets the rendezvous the value arguments are exchanged
-          between the processes and returned as the result of the
-          respective rendezvous system calls.  Both processes are
-          awakened when the rendezvous succeeds.
-
-          The set of tag values which two processes may use to
-          rendezvous-their tag space-is inherited when a process
-          forks, unless RFREND is set in the argument to rfork; see
-          fork(2).
-
-          If a rendezvous is interrupted the return value is ~0, so
-          that value should not be used in normal communication.
-
- * This simulates rendezvous with shared memory, sigsuspend, and SIGUSR1.
- */
-
 #include <u.h>
 #include <signal.h>
 #include <libc.h>
 
 #define DBG 0
 
-enum
-{
-	VOUSHASH = 257,
-};
-
-typedef struct Vous Vous;
-struct Vous
-{
-	Vous *link;
-	int pid;
-	int wokeup;
-	ulong tag;
-	ulong val1;		/* value for the sleeper */
-	ulong val2;		/* value for the waker */
-};
-
 static void
 ign(int x)
 {
@@ -73,128 +24,40 @@ ignusr1(int restart)
 	sigaction(SIGUSR1, &sa, nil);
 }
 
-static Vous vouspool[2048];
-static int nvousused;
-static Vous *vousfree;
-static Vous *voushash[VOUSHASH];
-static Lock vouslock;
-
-static Vous*
-getvous(void)
-{
-	Vous *v;
-
-	if(vousfree){
-		v = vousfree;
-		vousfree = v->link;
-	}else if(nvousused < nelem(vouspool))
-		v = &vouspool[nvousused++];
-	else{
-		fprint(2, "rendezvous: out of vous!\n");
-		abort();
-	}
-	return v;
-}
-
-static void
-putvous(Vous *v)
-{
-	v->link = vousfree;
-	vousfree = v;
-}
-
-static Vous*
-findvous(ulong tag)
-{
-	int h;
-	Vous *v, **l;
-
-	h = tag%VOUSHASH;
-	for(l=&voushash[h], v=*l; v; l=&(*l)->link, v=*l){
-		if(v->tag == tag){
-			*l = v->link;
-			v->link = nil;
-			return v;
-		}
-	}
-	return nil;
-}
-
-static Vous*
-mkvous(ulong tag)
+void
+_procsleep(_Procrend *r)
 {
-	Vous *v;
-	int h;
+	sigset_t mask;
 
-	h = tag%VOUSHASH;
-	v = getvous();
-	v->link = voushash[h];
-	v->tag = tag;
-	voushash[h] = v;
-	return v;
+	/*
+	 * Go to sleep.
+	 *
+	 * Block USR1, set the handler to interrupt system calls,
+	 * unlock the vouslock so our waker can wake us,
+	 * and then suspend.
+	 */
+	r->asleep = 1;
+	r->pid = getpid();
+
+	sigprocmask(SIG_SETMASK, nil, &mask);
+	sigaddset(&mask, SIGUSR1);
+	sigprocmask(SIG_SETMASK, &mask, nil);
+	ignusr1(0);
+	unlock(r->l);
+	sigdelset(&mask, SIGUSR1);
+	sigsuspend(&mask);
+
+	/*
+	 * We're awake.  Make USR1 not interrupt system calls.
+	 */
+	ignusr1(1);
+	assert(r->asleep == 0);
 }
 
-ulong
-rendezvous(ulong tag, ulong val)
+void
+_procwakeup(_Procrend *r)
 {
-	int vpid, pid;
-	ulong rval;
-	Vous *v;
-	sigset_t mask;
-
-	pid = getpid();
-	lock(&vouslock);
-	if((v = findvous(tag)) == nil){
-		/*
-		 * Go to sleep.
-		 *
-		 * Block USR1, set the handler to interrupt system calls,
-		 * unlock the vouslock so our waker can wake us,
-		 * and then suspend.
-		 */
-		v = mkvous(tag);
-		v->pid = pid;
-		v->val2 = val;
-		v->wokeup = 0;
-		sigprocmask(SIG_SETMASK, nil, &mask);
-		sigaddset(&mask, SIGUSR1);
-		sigprocmask(SIG_SETMASK, &mask, nil);
-		ignusr1(0);
-		if(DBG) fprint(2, "%d rv(%lux, %lux) -> s\n", pid, tag, val);
-		unlock(&vouslock);
-		sigdelset(&mask, SIGUSR1);
-		sigsuspend(&mask);
-
-		/*
-		 * We're awake.  Make USR1 not interrupt system calls.
-		 * Were we awakened or interrupted?
-		 */
-		ignusr1(1);
-		lock(&vouslock);
-		if(v->wokeup){
-			rval = v->val1;
-			if(DBG) fprint(2, "%d rv(%lux, %lux) -> g %lux\n", pid, tag, val, rval);
-		}else{
-			if(findvous(tag) != v){
-				fprint(2, "rendezvous: interrupted but not found in hash table\n");
-				abort();
-			}
-			rval = ~(ulong)0;
-			if(DBG) fprint(2, "%d rv(%lux, %lux) -> g i\n", pid, tag, val);
-		}
-		putvous(v);
-		unlock(&vouslock);
-	}else{
-		/*
-		 * Wake up sleeper.
-		 */
-		rval = v->val2;
-		v->val1 = val;
-		vpid = v->pid;
-		v->wokeup = 1;
-		if(DBG) fprint(2, "%d rv(%lux, %lux) -> g %lux, w %d\n", pid, tag, val, rval, vpid);
-		unlock(&vouslock);
-		kill(vpid, SIGUSR1);
-	}
-	return rval;
+	r->asleep = 0;
+	assert(r->pid >= 1);
+	kill(r->pid, SIGUSR1);
 }