From 4981fc0100c459a32cb9144f980972f15fb1fd2a Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 15 Mar 2001 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2001-03-15

---
 pc/devi82365.c  |   2 +-
 port/devproc.c  |  15 ++++++
 port/portdat.h  |   2 +
 port/portfns.h  |   4 ++
 port/proc.c     |  40 +++++++-------
 port/sysproc.c  |   1 +
 port/watchdog.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 181 insertions(+), 19 deletions(-)
 create mode 100644 port/watchdog.c

diff --git a/pc/devi82365.c b/pc/devi82365.c
index 3fe515536bf05adaddf59696fc879cdde77337c8..2d08091849fac8c57df880c4a947d18516ec2aab 100644
--- a/pc/devi82365.c
+++ b/pc/devi82365.c
@@ -294,7 +294,7 @@ pcmmap(int slotno, ulong offset, int len, int attr)
 		}
 		m->isa = PADDR(umbmalloc(0, len, Mgran));
 		if(m->isa == 0){
-			print("pcmmap: out of isa space\n");
+			print("pcmmap: %d out of isa space\n", len);
 			unlock(&pp->mlock);
 			return 0;
 		}
diff --git a/port/devproc.c b/port/devproc.c
index 5422f71247f38dcebd8fa0fde0bff1a2bb27b3ef..ff0fe91a0687aae05646fe73222bdf699821f6cf 100644
--- a/port/devproc.c
+++ b/port/devproc.c
@@ -948,6 +948,21 @@ procctlreq(Proc *p, char *va, int n)
 		if(i > p->basepri && !iseve())
 			error(Eperm);
 		p->basepri = i;
+		p->fixedpri = 0;
+	}
+	else
+	if(strncmp(buf, "fixedpri", 8) == 0) {
+		if(n < 9)
+			error(Ebadctl);
+		i = atoi(buf+9);
+		if(i < 0)
+			i = 0;
+		if(i >= Nrq)
+			i = Nrq - 1;
+		if(i > p->basepri && !iseve())
+			error(Eperm);
+		p->basepri = i;
+		p->fixedpri = 1;
 	}
 	else
 	if(strncmp(buf, "wired", 5) == 0) {
diff --git a/port/portdat.h b/port/portdat.h
index 4d007c2336a8790ca2778afb03e7f84db2518928..eeba31aec8eed3d6c59850df08de2fb285cb5f3c 100644
--- a/port/portdat.h
+++ b/port/portdat.h
@@ -41,6 +41,7 @@ typedef struct Session	Session;
 typedef struct Talarm	Talarm;
 typedef struct Target	Target;
 typedef struct Waitq	Waitq;
+typedef struct Watchdog	Watchdog;
 typedef int    Devgen(Chan*, Dirtab*, int, int, Dir*);
 
 
@@ -613,6 +614,7 @@ struct Proc
 	Mach	*mp;		/* machine this process last ran on */
 	ulong	priority;	/* priority level */
 	ulong	basepri;	/* base priority level */
+	uchar	fixedpri;	/* priority level deson't change */
 	ulong	rt;		/* # ticks used since last blocked */
 	ulong	art;		/* avg # ticks used since last blocked */
 	ulong	movetime;	/* last time process switched processors */
diff --git a/port/portfns.h b/port/portfns.h
index d74f7175dc776c6d68723708bd7da124b90e5421..15e770f6a7f8d05e32ad8a8f6259a4176c402518 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -323,6 +323,10 @@ void*		vmemchr(void*, int, int);
 Proc*		wakeup(Rendez*);
 int		walk(Chan**, char*, int);
 int		walkname(Chan**, char*, int);
+Watchdog*	wdCreate(void);
+char*		wdDelete(Watchdog*);
+char*		wdStart(Watchdog*, ulong, void (*)(int), int);
+char*		wdCancel(Watchdog*);
 void		wlock(RWlock*);
 void		wunlock(RWlock*);
 void*		xalloc(ulong);
diff --git a/port/proc.c b/port/proc.c
index ebb8e429c6a54e8100a7491ece01f44c1060da1f..906fe0feb65b53c5ab85079317b3887fed029b95 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -146,26 +146,30 @@ ready(Proc *p)
 
 	s = splhi();
 
-	/* history counts */
-	if(p->state == Running){
-		p->rt++;
-		pri = ((p->art + (p->rt<<1))>>2)/Squantum;
+	if(p->fixedpri){
+		pri = p->basepri;
 	} else {
-		p->art = (p->art + (p->rt<<1))>>2;
-		p->rt = 0;
-		pri = p->art/Squantum;
-	}
-	pri = p->basepri - pri;
-	if(pri < 0)
-		pri = 0;
-
-	/* the only intersection between the classes is at PriNormal */
-	if(pri < PriNormal && p->basepri > PriNormal)
-		pri = PriNormal;
+		/* history counts */
+		if(p->state == Running){
+			p->rt++;
+			pri = ((p->art + (p->rt<<1))>>2)/Squantum;
+		} else {
+			p->art = (p->art + (p->rt<<1))>>2;
+			p->rt = 0;
+			pri = p->art/Squantum;
+		}
+		pri = p->basepri - pri;
+		if(pri < 0)
+			pri = 0;
+	
+		/* the only intersection between the classes is at PriNormal */
+		if(pri < PriNormal && p->basepri > PriNormal)
+			pri = PriNormal;
 
-	/* stick at low priority any process waiting for a lock */
-	if(p->lockwait)
-		pri = PriLock;
+		/* stick at low priority any process waiting for a lock */
+		if(p->lockwait)
+			pri = PriLock;
+	}
 
 	p->priority = pri;
 	rq = &runq[p->priority];
diff --git a/port/sysproc.c b/port/sysproc.c
index 4dc60186198b824622f9aa56bb9c119f2f095827..db255d84bfdf5dd0a5bfd5dfce84524b4f036d6f 100644
--- a/port/sysproc.c
+++ b/port/sysproc.c
@@ -187,6 +187,7 @@ sysrfork(ulong *arg)
 	flushmmu();
 	p->priority = up->priority;
 	p->basepri = up->basepri;
+	p->fixedpri = up->fixedpri;
 	p->mp = up->mp;
 	wm = up->wired;
 	if(wm)
diff --git a/port/watchdog.c b/port/watchdog.c
new file mode 100644
index 0000000000000000000000000000000000000000..27327d64a6c528e7fefe4d5b5a4e3ad282f190c8
--- /dev/null
+++ b/port/watchdog.c
@@ -0,0 +1,136 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"../port/error.h"
+
+#define WDMAGIC 0xfaceface
+
+struct Watchdog
+{
+	Watchdog *next;
+	ulong	magic;
+	ulong	ticks;
+	void	(*f)(int);
+	ulong	arg;
+	uchar	armed;
+};
+
+struct {
+	Lock;
+	Watchdog *wd;
+} wdalloc;
+
+Watchdog*
+wdCreate(void)
+{
+	Watchdog *wd;
+
+	wd = mallocz(sizeof(Watchdog), 1);
+	if(wd == nil)
+		return nil;
+	wd->magic = WDMAGIC;
+	return wd;
+}
+
+static char*
+wdunlink(Watchdog *wd, ulong magic)
+{
+	char *rv;
+	Watchdog **l;
+
+	rv = "not started";
+	ilock(&wdalloc);
+	wd->magic = magic;
+	for(l = &wdalloc.wd; *l != nil; l = &(*l)->next)
+		if(*l == wd){
+			*l = wd->next;
+			rv = nil;
+			break;
+		}
+	wd->armed = 0;
+	iunlock(&wdalloc);
+	return rv;
+}
+
+char*
+wdDelete(Watchdog *wd)
+{
+	if(wd->magic != WDMAGIC)
+		return "not a watchdog";
+
+	wdunlink(wd, ~WDMAGIC);
+	free(wd);
+
+	return nil;
+}
+
+char*
+wdStart(Watchdog *wd, ulong ms, void (*f)(int), int arg)
+{
+	Watchdog **l;
+
+	if(wd->magic != WDMAGIC)
+		return "not a watchdog";
+
+	/* unchain it in case it already is chained */
+	if(wd->armed)
+		wdunlink(wd, WDMAGIC);
+
+	/* chain the watchdogs in time order */
+	ilock(&wdalloc);
+	wd->ticks = MS2TK(ms) + MACHP(0)->ticks;
+	wd->f = f;
+	wd->arg = arg;
+	wd->armed = 1;
+	for(l = &wdalloc.wd; *l != nil; l = &(*l)->next)
+		if(wd->ticks < (*l)->ticks)
+			break;
+	wd->next = *l;
+	*l = wd;
+	iunlock(&wdalloc);
+
+	return nil;
+}
+
+char*
+wdCancel(Watchdog *wd)
+{
+	if(wd->magic != WDMAGIC)
+		return "not a watchdog";
+	return wdunlink(wd, WDMAGIC);
+}
+
+static void
+wdclock(void)
+{
+	Watchdog *wd, **l;
+
+	/* find the barking dogs, remoe from the chain */
+	ilock(&wdalloc);
+	wd = wdalloc.wd;
+	for(l = &wdalloc.wd; *l != nil; l = &(*l)->next)
+		if(MACHP(0)->ticks - (*l)->ticks >= 0x10000000)
+			break;
+	if(l == &wdalloc.wd)
+		wd = nil;
+	else {
+		wdalloc.wd = *l;
+		*l = nil;
+	}
+	iunlock(&wdalloc);
+
+	/* let them run */
+	for(; wd != nil; wd = wd->next){
+		wd->ticks = 0;
+		wd->armed = 0;
+		(*wd->f)(wd->arg);
+	}
+}
+
+void
+watchdoglink(void)
+{
+	addclock0link(wdclock);
+}