9/port: revert timer wheel change, breaks pi4 boot, needs more time investigating

1 files changed, 84 insertions, 66 deletions

diff --git a/sys/src/9/port/alarm.c b/sys/src/9/port/alarm.c
index 95516222f..49dec2ccb 100644
--- a/sys/src/9/port/alarm.c
+++ b/sys/src/9/port/alarm.c
@@ -3,91 +3,109 @@
 #include	"mem.h"
 #include	"dat.h"
 #include	"fns.h"
-#include	"error.h"
 
-static Proc	*tripped;
+static Alarms	alarms;
 static Rendez	alarmr;
-static Lock	triplk;
-
-static int
-tfn(void *)
-{
-	int t;
-
-	ilock(&triplk);
-	t = (tripped != nil);
-	iunlock(&triplk);
-	return t;
-}
-
-/*
- *  called every clock tick on cpu0
- */
-static void
-tripalarm(Ureg*, Timer *t)
-{
-	ilock(&triplk);
-	t->p->palarm = tripped;
-	tripped = t->p;
-	iunlock(&triplk);
-
-	wakeup(&alarmr);
-}
 
 void
 alarmkproc(void*)
 {
-	static Note alarmnote = {
-		"alarm",
-		NUser,
-		1,
-	};
-	Proc *p, *n;
-	Timer *a;
+	Proc *rp;
+	ulong now, when;
 
 	while(waserror())
 		;
 
-	while(1){
-		ilock(&triplk);
-		p = tripped;
-		tripped = nil;
-		iunlock(&triplk);
-
-		for(; p != nil; p = n){
-			n = p->palarm;
-			a = &p->alarm;
-			if(!canqlock(&p->debug)){
-				a->tns = MS2NS(10);
-				timeradd(a);
+	for(;;){
+		now = MACHP(0)->ticks;
+		qlock(&alarms);
+		for(rp = alarms.head; rp != nil; rp = rp->palarm){
+			if((when = rp->alarm) == 0)
 				continue;
+			if((long)(now - when) < 0)
+				break;
+			if(!canqlock(&rp->debug))
+				break;
+			if(rp->alarm != 0){
+				static Note alarm = {
+					"alarm",
+					NUser,
+					1,
+				};
+				incref(&alarm);
+				pushnote(rp, &alarm);
+				rp->alarm = 0;
 			}
-			incref(&alarmnote);
-			pushnote(p, &alarmnote);
-			qunlock(&p->debug);
+			qunlock(&rp->debug);
 		}
-		sleep(&alarmr, tfn, nil);
+		alarms.head = rp;
+		qunlock(&alarms);
+
+		sleep(&alarmr, return0, 0);
+	}
+}
+
+/*
+ *  called every clock tick on cpu0
+ */
+void
+checkalarms(void)
+{
+	Proc *p;
+	ulong now, when;
+
+	p = alarms.head;
+	if(p != nil){
+		now = MACHP(0)->ticks;
+		when = p->alarm;
+		if(when == 0 || (long)(now - when) >= 0)
+			wakeup(&alarmr);
 	}
 }
 
 ulong
 procalarm(ulong time)
 {
-	uvlong old;
-	Timer *a;
+	Proc **l, *f;
+	ulong when, old;
+
+	when = MACHP(0)->ticks;
+	old = up->alarm;
+	if(old) {
+		old -= when;
+		if((long)old > 0)
+			old = tk2ms(old);
+		else
+			old = 0;
+	}
+	if(time == 0) {
+		up->alarm = 0;
+		return old;
+	}
+	when += ms2tk(time);
+	if(when == 0)
+		when = 1;
 
-	a = &up->alarm;
-	old = a->tns;
-	timerdel(a);
+	qlock(&alarms);
+	l = &alarms.head;
+	for(f = *l; f; f = f->palarm) {
+		if(up == f){
+			*l = f->palarm;
+			break;
+		}
+		l = &f->palarm;
+	}
+	l = &alarms.head;
+	for(f = *l; f; f = f->palarm) {
+		time = f->alarm;
+		if(time != 0 && (long)(time - when) >= 0)
+			break;
+		l = &f->palarm;
+	}
+	up->palarm = f;
+	*l = up;
+	up->alarm = when;
+	qunlock(&alarms);
 
-	lock(a);
-	a->tns = MS2NS(time);
-	a->tf = tripalarm;
-	a->tmode = Trelative;
-	a->p = up;
-	a->ta = nil;
-	unlock(a);
-	if(time != 0)
-		timeradd(a);
-	return NS2MS(old);
+	return old;
 }