9/port: allow kiloprocs -- allocate procs lazily

Treallocate the small data structures around procs eagerly,
but use malloc to allocate the large proc data structures
when we need them, which allows us to scale to many more procs.

There are still many scalability bottlenecks, so we only crank
up the nproc limit by a little bit this time around, and crank
it up more as we optimize more.

1 files changed, 11 insertions, 9 deletions

diff --git a/sys/src/9/port/devproc.c b/sys/src/9/port/devproc.c
index d19d4a9a0..503b00922 100644
--- a/sys/src/9/port/devproc.c
+++ b/sys/src/9/port/devproc.c
@@ -149,7 +149,8 @@ static char *sname[]={ "Text", "Data", "Bss", "Stack", "Shared", "Phys", "Fixed"
 #define	QSHIFT	5	/* location in qid of proc slot # */
 
 #define	QID(q)		((((ulong)(q).path)&0x0000001F)>>0)
-#define	SLOT(q)		(((((ulong)(q).path)&0x07FFFFFE0)>>QSHIFT)-1)
+#define	SLOTMAX		0x4000000
+#define	SLOT(q)		(((((ulong)(q).path)>>QSHIFT)&(SLOTMAX-1))-1)
 #define	PID(q)		((q).vers)
 #define	NOTEID(q)	((q).vers)
 
@@ -202,6 +203,8 @@ procgen(Chan *c, char *name, Dirtab *tab, int, int s, Dir *dp)
 			return -1;
 
 		p = proctab(s);
+		if(p == nil)
+			return 0;
 		pid = p->pid;
 		if(pid == 0)
 			return 0;
@@ -227,7 +230,7 @@ procgen(Chan *c, char *name, Dirtab *tab, int, int s, Dir *dp)
 		panic("procgen");
 
 	tab = &procdir[s];
-	path = c->qid.path&~(((1<<QSHIFT)-1));	/* slot component */
+	path = c->qid.path&~((1<<QSHIFT)-1);	/* slot component */
 
 	/* p->procmode determines default mode for files in /proc */
 	p = proctab(SLOT(c->qid));
@@ -281,8 +284,9 @@ _proctrace(Proc* p, Tevent etype, vlong ts)
 static void
 procinit(void)
 {
-	if(conf.nproc >= (1<<(16-QSHIFT))-1)
-		print("warning: too many procs for devproc\n");
+	/* slot masks: lets see how big we can go */
+	if(conf.nproc > SLOTMAX)
+		panic("warning: too many procs for devproc\n");
 }
 
 static Chan*
@@ -335,8 +339,7 @@ changenoteid(Proc *p, ulong noteid)
 		setnoteid(p, noteid);
 		return;
 	}
-	for(i = 0; i < conf.nproc; i++){
-		pp = proctab(i);
+	for(i = 0; (pp = proctab(i)) != nil; i++){
 		if(pp->noteid != noteid || pp->kp)
 			continue;
 		if(strcmp(pp->user, p->user) == 0){
@@ -354,8 +357,7 @@ postnotepg(ulong noteid, char *n, int flag)
 	Proc *p;
 	int i;
 
-	for(i = 0; i < conf.nproc; i++){
-		p = proctab(i);
+	for(i = 0; (p = proctab(i)) != nil; i++){
 		if(p == up)
 			continue;
 		if(p->noteid != noteid || p->kp)
@@ -414,7 +416,7 @@ procopen(Chan *c, int omode0)
 		nexterror();
 	}
 	pid = PID(c->qid);
-	if(p->pid != pid)
+	if(p == nil || p->pid != pid)
 		error(Eprocdied);
 
 	omode = openmode(omode0);