From 16c2bd6d14bab9dea7d12a7db27524c85f1a2671 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 9 Jan 1995 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1995-01-09

---
 carrera/clock.c |  9 ++-------
 carrera/trap.c  |  2 +-
 pc/clock.c      |  2 +-
 port/proc.c     | 14 ++++++++++----
 port/taslock.c  | 44 ++++++++++++++++++++++----------------------
 power/clock.c   |  2 +-
 6 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/carrera/clock.c b/carrera/clock.c
index 7e655480160d484ed99486f586c3db6707f3d09f..da3bef9a3b828bcac5a48e7c52715b419742ff92 100644
--- a/carrera/clock.c
+++ b/carrera/clock.c
@@ -78,13 +78,8 @@ clock(Ureg *ur)
 	if(up == 0 || up->state != Running)
 		return;
 
-	if(anyready()) {
-		n = up->inlock;
-		if(n == 0)
-			sched();
-		else
-			up->inlock = n-1;
-	}
+	if(anyready() && !up->inlock)
+		sched();
 
 	/* user profiling clock */
 	if(ur->status & KUSER)
diff --git a/carrera/trap.c b/carrera/trap.c
index 1f6bcaf59cd3db5c559cfb1710c26f9d171385d3..a98f8308343eb7377e904c9de80dcc652889fff5 100644
--- a/carrera/trap.c
+++ b/carrera/trap.c
@@ -397,7 +397,7 @@ intr(Ureg *ur)
 	}
 
 	/* preemptive scheduling */
-	if(up && up->state == Running && anyhigher() && up->inlock == 0)
+	if(up && up->state == Running && anyhigher() && !up->inlock)
 		sched();
 }
 
diff --git a/pc/clock.c b/pc/clock.c
index 713f6efe2db9333190f94f19197ce9e9db36f84d..042928816766422d5f33b0f16128ea0444c7b475 100644
--- a/pc/clock.c
+++ b/pc/clock.c
@@ -45,7 +45,7 @@ clock(Ureg *ur, void *arg)
 	uartclock();
 
 	if(up && up->state == Running){
-		if(anyready())
+		if(anyready() && !up->inlock)
 			sched();
 	
 		/* user profiling clock */
diff --git a/port/proc.c b/port/proc.c
index 734ea01b58c829886bf8fb3cc4736027908fcc04..005ac95edfe44b3dfd36776d233faf565fb63297 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -115,7 +115,6 @@ anyhigher(void)
 	Proc *p;
 	int pri;
 
-	return runq.n;
 	pri = up->pri;
 	for(p=runq.head; p; p=p->rnext)
 		if(p->pri <= pri)
@@ -961,6 +960,13 @@ accounttime(void)
 		p->pri += priconst[p->nice];
 	}
 
+	if(up) {
+		i = up->inlock-1;
+		if(i < 0)
+			i = 0;
+		up->inlock = i;
+	}
+
 	/* only one processor gets to compute system load averages */
 	if(m->machno != 0)
 		return;
@@ -974,8 +980,8 @@ accounttime(void)
 
 	/*
 	 * decay per-process cpu usage
-	 *	pri = (7/8)*pri twice per second
-	 *	tc = (7/8)^2/(1-(7/8)^2) = 3.27 sec
+	 *	pri = (3/4)*pri twice per second
+	 *	tc = (3/4)^2/(1-(3/4)^2) = 1.286 sec
 	 */
 	m0ticks--;
 	if(m0ticks <= 0) {
@@ -984,7 +990,7 @@ accounttime(void)
 		for(i=conf.nproc-1; i!=0; i--,p++)
 			if(p->state != Dead) {
 				pri = p->pri;
-				pri -= pri >> 3;
+				pri -= pri >> 2;
 				p->pri = pri;
 			}
 	}
diff --git a/port/taslock.c b/port/taslock.c
index ad282313701c979078730b19ae048bb597a3493e..4b47aabad23cffc51b8f183406a946b5155e56b6 100644
--- a/port/taslock.c
+++ b/port/taslock.c
@@ -38,33 +38,23 @@ lock(Lock *l)
 	}
 }
 
-void
-ilock(Lock *l)
+int
+canlock(Lock *l)
 {
-	ulong x;
-
-	x = splhi();
-	if(tas(&l->key) == 0){
-		l->sr = x;
-		return;
-	}
+	int n;
 
-	for(;;){
-		while(l->key)
-			;
-		if(tas(&l->key) == 0){
-			l->sr = x;
-			return;
+	if(up) {
+		n = up->inlock;
+		up->inlock = n+2;
+		if(tas(&l->key)) {
+			up->inlock = n;
+			return 0;
 		}
+		return 1;
 	}
-}
 
-int
-canlock(Lock *l)
-{
 	if(tas(&l->key))
 		return 0;
-
 	return 1;
 }
 
@@ -73,13 +63,23 @@ unlock(Lock *l)
 {
 	int n;
 
-	l->key = 0;
 	if(up) {
 		n = up->inlock-2;
 		if(n < 0)
 			n = 0;
 		up->inlock = n;
 	}
+	l->key = 0;
+}
+
+void
+ilock(Lock *l)
+{
+	ulong sr;
+
+	sr = splhi();
+	lock(l);
+	l->sr = sr;
 }
 
 void
@@ -88,6 +88,6 @@ iunlock(Lock *l)
 	ulong sr;
 
 	sr = l->sr;
-	l->key = 0;
+	unlock(l);
 	splx(sr);
 }
diff --git a/power/clock.c b/power/clock.c
index 4c865ca970782c07b1a0525d1f9c443db082d348..e7caaf0fac7bcbc00e731946a4c73c65f5c11b4a 100644
--- a/power/clock.c
+++ b/power/clock.c
@@ -103,7 +103,7 @@ clock(Ureg *ur)
 	if(up == 0 || (ur->status&IEP) == 0 || up->state != Running)
 		return;
 
-	if(anyready())
+	if(anyready() && !up->inlock)
 		sched();
 
 	/* user profiling clock */