From 908525d98b4afe88ef50ce13bd388c319597465d Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 6 Jun 1998 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1998-06-06

---
 carrera/dat.h   |  2 +-
 carrera/l.s     |  2 ++
 pc/dat.h        |  3 +-
 pc/etherelnk3.c |  2 ++
 pc/l.s          |  2 +-
 pc/trap.c       |  4 ---
 port/portdat.h  |  4 +--
 port/portfns.h  |  1 +
 port/proc.c     |  9 +++--
 port/taslock.c  | 94 +++++++++++++++++++++++++------------------------
 10 files changed, 65 insertions(+), 58 deletions(-)

diff --git a/carrera/dat.h b/carrera/dat.h
index 0998b88da103745be6edacbdd62cee8987e94c2d..b340c7bfa21fcc38cefde1cca3c21e861c64b380 100644
--- a/carrera/dat.h
+++ b/carrera/dat.h
@@ -28,7 +28,6 @@ struct Lock
 	ulong	sr;
 	ulong	pc;
 	Proc	*p;
-	ushort	pri;
 	ushort	isilock;
 };
 
@@ -114,6 +113,7 @@ struct Mach
 	int	speed;			/* cpu speed */
 	ulong	delayloop;		/* for the delay() routine */
 	int	nrdy;
+	ulong	fairness;		/* for runproc */
 
 	int	pfault;
 	int	cs;
diff --git a/carrera/l.s b/carrera/l.s
index f9c0da80966a353e4be16ee96e8a47aca375c6ec..9b4b363e7bb3864a062a287b1dcdd64c3e0f44f3 100644
--- a/carrera/l.s
+++ b/carrera/l.s
@@ -103,6 +103,8 @@ TEXT	splhi(SB), $0
 
 TEXT	splx(SB), $0
 	MOVW	R31, 12(R(MACH))	/* save PC in m->splpc */
+
+TEXT	splxpc(SB), $0			/* for iunlock */
 	MOVW	M(STATUS), R2
 	WAIT
 	AND	$IE, R1
diff --git a/pc/dat.h b/pc/dat.h
index fbe1649d735a7181a8de50d2093f2a33331ebcea..b4d22fed551cc980806dcef5588a46ea9d7fd1c1 100644
--- a/pc/dat.h
+++ b/pc/dat.h
@@ -28,7 +28,6 @@ struct Lock
 	ulong	sr;
 	ulong	pc;
 	Proc	*p;
-	ushort	pri;
 	ushort	isilock;
 };
 
@@ -162,6 +161,8 @@ struct Mach
 	Lock	alarmlock;		/* access to alarm list */
 	void*	alarm;			/* alarms bound to this clock */
 
+	ulong	fairness;		/* for runproc */
+
 	int	tlbfault;
 	int	tlbpurge;
 	int	pfault;
diff --git a/pc/etherelnk3.c b/pc/etherelnk3.c
index 7a69e452d9f285cbbe6698c4786101476d9a0267..1b5be6abd00e18e47c8c0234030f087e05ac80d9 100644
--- a/pc/etherelnk3.c
+++ b/pc/etherelnk3.c
@@ -1763,6 +1763,8 @@ else
 		for(i = 0; i < ether->nopt; i++){
 			if(cistrcmp(ether->opt[i], "fullduplex") == 0)
 				an |= 0x0100;
+			else if(cistrcmp(ether->opt[i], "100BASE-TXFD") == 0)
+				an |= 0x0100;
 			else if(cistrcmp(ether->opt[i], "force100") == 0)
 				an |= 0x0080;
 		}
diff --git a/pc/l.s b/pc/l.s
index 10085d14f356a66dfa0f5ae53dbdecbeb847eb52..0df9016e60f89da59b0c5e90d9e5c70f01fad70a 100644
--- a/pc/l.s
+++ b/pc/l.s
@@ -441,7 +441,7 @@ TEXT splx(SB), $0
 	MOVL	(SP), BX
 	MOVL	BX, (AX)
 
-TEXT _splx(SB), $0				/* for iunlock */
+TEXT splxpc(SB), $0				/* for iunlock */
 	MOVL	s+0(FP), AX
 	PUSHL	AX
 	POPFL
diff --git a/pc/trap.c b/pc/trap.c
index 51dc482024088afc2996ed52274d74557f6d41d2..274071db6012fa7e38150a600cf8351d712dacc2 100644
--- a/pc/trap.c
+++ b/pc/trap.c
@@ -419,10 +419,6 @@ syscall(Ureg* ureg)
 		splhi();
 		notify(ureg);
 	}
-	if (up->nlocks != 0) {
-		print("nlock = %d\n", up->nlocks);
-		up->nlocks = 0;
-	}
 }
 
 /*
diff --git a/port/portdat.h b/port/portdat.h
index 82bb8e299c99b0e8b1c2b587f201dc3265c573a8..5ff0086f13f3736aa02abecc670c7c1ca92be3a7 100644
--- a/port/portdat.h
+++ b/port/portdat.h
@@ -518,7 +518,7 @@ enum
 	NNOTE = 5,
 
 	Nrq		= 20,	/* number of scheduler priority levels */
-	PriLock		= 19,	/* priority for processes holding locks */
+	PriLock		= 0,	/* priority for processes waiting on a lock */
 	PriNormal	= 10,	/* base priority for normal processes */
 	PriKproc	= 13,	/* base priority for kernel processes */
 	PriRoot		= 13,	/* base priority for root processes */
@@ -601,7 +601,7 @@ struct Proc
 	Note	lastnote;
 	int	(*notify)(void*, char*);
 
-	int	nlocks;		/* Number of locks held */
+	int	lockwait;	/* waiting for lock to be released */
 
 	Mach	*wired;
 	Mach	*mp;		/* machine this process last ran on */
diff --git a/port/portfns.h b/port/portfns.h
index 1f72be919f451921b2141a5236df949a7e048cb6..4b442324d11e0d60af37e550631eb2439af36658 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -284,6 +284,7 @@ void*		smalloc(ulong);
 int		splhi(void);
 int		spllo(void);
 void		splx(int);
+void		splxpc(int);
 void		srvrecover(Chan*, Chan*);
 void		swapinit(void);
 Block*		trimblock(Block*, int, int);
diff --git a/port/proc.c b/port/proc.c
index 2ec0be280740885897969364aef7bb6c5d3b6b9b..e40c1179f9fee8f6b90fef99cb99801fb6437351 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -158,6 +158,10 @@ ready(Proc *p)
 	if(pri < PriNormal && p->basepri > PriNormal)
 		pri = PriNormal;
 
+	/* stick at low priority any process waiting for a lock */
+	if(p->lockwait)
+		pri = PriLock;
+
 	p->priority = pri;
 	rq = &runq[p->priority];
 
@@ -198,7 +202,7 @@ loop:
 		 *  processor can run given affinity constraints
 		 *  and that hasn't run in a while
 		 */
-		if((m->ticks & 3) == 0){
+		if((m->fairness++ & 3) == 0){
 			for(rq = runq; rq < &runq[Nrq]; rq++){
 				p = rq->head;
 				if(p == 0)
@@ -331,7 +335,6 @@ newproc(void)
 		panic("pidalloc");
 	if(p->kstack == 0)
 		p->kstack = smalloc(KSTACK);
-	p->nlocks = 0;
 
 	return p;
 }
@@ -893,7 +896,7 @@ dumpaproc(Proc *p)
 	s = p->psstate;
 	if(s == 0)
 		s = "kproc";
-	print("%3d:%10s pc %8lux dbgpc %8lux  %8s (%s) ut %ld st %ld bss %lux\n",
+	print("%3d:%10s pc %8lux dbgpc %8lux  %8s (%s) ut %ld st %ld bss %lux pri %d\n",
 		p->pid, p->text, p->pc, dbgpc(p),  s, statename[p->state],
 		p->time[0], p->time[1], bss, p->priority);
 }
diff --git a/port/taslock.c b/port/taslock.c
index a161e07f03e6027b8afb3f829e052a7d5a635ff1..78425bcf39a6593703b975419dcbc4dfeae2b0ba 100644
--- a/port/taslock.c
+++ b/port/taslock.c
@@ -5,12 +5,23 @@
 #include "fns.h"
 #include "../port/error.h"
 
+struct {
+	ulong	locks;
+	ulong	glare;
+	ulong	inglare;
+} lockstats;
+
 void
 lockloop(Lock *l, ulong pc)
 {
+	Proc *p;
+
+	p = l->p;
 	print("lock loop key 0x%lux pc 0x%lux held by pc 0x%lux proc %d\n",
-		l->key, pc, l->pc, l->p ? l->p->pid : 0);
+		l->key, pc, l->pc, p ? p->pid : 0);
 	dumpaproc(up);
+	if(p != nil)
+		dumpaproc(p);
 
 	if(up && up->state == Running && islo())
 		sched();
@@ -19,27 +30,33 @@ lockloop(Lock *l, ulong pc)
 void
 lock(Lock *l)
 {
-	int i;
-	ulong pc;
+	int i, cansched;
+	ulong pc, oldpri;
 
 	pc = getcallerpc(l);
 
+lockstats.locks++;
 	if(tas(&l->key) == 0){
 		l->pc = pc;
 		l->p = up;
 		l->isilock = 0;
-		if(up){
-			up->nlocks++;
-			l->pri = up->priority;
-			up->priority = PriLock;
-		}
 		return;
 	}
 
+lockstats.glare++;
+	cansched = up != nil && up->state == Running;
+	if(cansched){
+		oldpri = up->priority;
+		up->lockwait = 1;
+		up->priority = PriLock;
+	} else
+		oldpri = 0;
+
 	for(;;){
+lockstats.inglare++;
 		i = 0;
 		while(l->key){
-			if(conf.nmach < 2){
+			if(conf.nmach < 2 && cansched){
 				if(i++ > 1000){
 					i = 0;
 					lockloop(l, pc);
@@ -56,10 +73,9 @@ lock(Lock *l)
 			l->pc = pc;
 			l->p = up;
 			l->isilock = 0;
-			if(up){
-				up->nlocks++;
-				l->pri = up->priority;
-				up->priority = PriLock;
+			if(cansched){
+				up->lockwait = 0;
+				up->priority = oldpri;
 			}
 			return;
 		}
@@ -70,14 +86,14 @@ void
 ilock(Lock *l)
 {
 	ulong x;
-	ulong pc;
+	ulong pc, oldpri;
+	int cansched;
 
 	pc = getcallerpc(l);
+lockstats.locks++;
 
 	x = splhi();
 	if(tas(&l->key) == 0){
-		if (up)
-			up->nlocks++;
 		l->sr = x;
 		l->pc = pc;
 		l->p = up;
@@ -85,21 +101,32 @@ ilock(Lock *l)
 		return;
 	}
 
+lockstats.glare++;
+	cansched = up != nil && up->state == Running;
+	if(cansched){
+		oldpri = up->priority;
+		up->lockwait = 1;
+		up->priority = PriLock;
+	} else
+		oldpri = 0;
 	if(conf.nmach < 2)
 		panic("ilock: no way out: pc %uX\n", pc);
 
 	for(;;){
+lockstats.inglare++;
 		splx(x);
 		while(l->key)
 			;
 		x = splhi();
 		if(tas(&l->key) == 0){
-			if (up)
-			 up->nlocks++;
 			l->sr = x;
 			l->pc = pc;
 			l->p = up;
 			l->isilock = 1;
+			if(cansched){
+				up->lockwait = 0;
+				up->priority = oldpri;
+			}
 			return;
 		}
 	}
@@ -114,41 +141,19 @@ canlock(Lock *l)
 	l->pc = getcallerpc(l);
 	l->p = up;
 	l->isilock = 0;
-	if(up){
-		up->nlocks++;
-		l->pri = up->priority;
-		up->priority = PriLock;
-	}
 	return 1;
 }
 
 void
 unlock(Lock *l)
 {
-	int p;
-	ulong pc;
-
-	pc = getcallerpc(l);
 
-	p = l->pri;
 	if(l->key == 0)
 		print("unlock: not locked: pc %uX\n", getcallerpc(l));
 	if(l->isilock)
 		print("iunlock of lock: pc %lux, held by %lux\n", getcallerpc(l), l->pc);
 	l->pc = 0;
 	l->key = 0;
-	if(up) {
-		if (up != l->p) {
-			print("different unlocker 0x%lux pc 0x%lux held by pc 0x%lux proc %d\n",
-				l->key, pc, l->pc, l->p ? l->p->pid : 0);
-			dumpaproc(up);
-		}
-		if (--up->nlocks < 0)
-			print("number of locks < 0: pc %lux, held by %lux\n",
-				getcallerpc(l), l->pc);
-		if (p < up->priority)
-			up->priority = p;
-	}
 	coherence();
 }
 
@@ -165,11 +170,8 @@ iunlock(Lock *l)
 	sr = l->sr;
 	l->pc = 0;
 	l->key = 0;
-	if(up) {
-		if (--up->nlocks < 0)
-			print("number of locks < 0: pc %lux, held by %lux\n",
-				getcallerpc(l), l->pc);
-	}
-	splx(sr);
 	coherence();
+
+	m->splpc = getcallerpc(l);
+	splxpc(sr);
 }