shithub: riscv

Info  •  Files  •  Log  •  Branches

kernel: add pidalloc() and reuse pid once the counter wraps arround

--- a/sys/src/9/port/portdat.h

+++ b/sys/src/9/port/portdat.h

@@ -768,7 +768,6 @@

 extern	char	hostdomain[];

 extern	uchar	initcode[];

 extern	Queue*	kprintoq;

-extern 	Ref	noteidalloc;

 extern	int	nsyscall;

 extern	Palloc	palloc;

 extern	Queue*	serialoq;

--- a/sys/src/9/port/portfns.h

+++ b/sys/src/9/port/portfns.h

@@ -214,6 +214,7 @@

 void		pexit(char*, int);

 void		pgrpcpy(Pgrp*, Pgrp*);

 void		pgrpnote(ulong, char*, long, int);

+int		pidalloc(Proc*);

 void		pio(Segment *, ulong, ulong, Page **);

 #define		poperror()		up->nerrlab--

 void		portcountpagerefs(ulong*, int);

--- a/sys/src/9/port/proc.c

+++ b/sys/src/9/port/proc.c

@@ -9,7 +9,6 @@

 int	schedgain = 30;	/* units in seconds */

 int	nrdy;

-Ref	noteidalloc;

 void updatecpu(Proc*);

 int reprioritize(Proc*);

@@ -19,8 +18,6 @@

 long preempts;

 ulong load;

-static Ref	pidalloc;

-

 static struct Procalloc

 {

 	Lock;

@@ -56,8 +53,7 @@

 	"Waitrelease",

 };

-static void pidhash(Proc*);

-static void pidunhash(Proc*);

+static void pidfree(Proc*);

 static void rebalance(void);

 /*

@@ -637,11 +633,7 @@

 	p->nargs = 0;

 	p->setargs = 0;

 	memset(p->seg, 0, sizeof p->seg);

-	p->pid = incref(&pidalloc);

-	pidhash(p);

-	p->noteid = incref(&noteidalloc);

-	if(p->pid==0 || p->noteid==0)

-		panic("pidalloc");

+	p->noteid = pidalloc(p);

 	if(p->kstack == 0)

 		p->kstack = smalloc(KSTACK);

@@ -1182,7 +1174,7 @@

 	qunlock(&up->seglock);

 	lock(&up->exl);		/* Prevent my children from leaving waits */

-	pidunhash(up);

+	pidfree(up);

 	up->pid = 0;

 	wakeup(&up->waitr);

 	unlock(&up->exl);

@@ -1597,20 +1589,33 @@

 	m->load = (m->load*(HZ-1)+n)/HZ;

 }

-static void

-pidhash(Proc *p)

+int

+pidalloc(Proc *p)

 {

-	int h;

+	static Ref ref;

+	int pid, h;

+	Proc *x;

-	h = p->pid % nelem(procalloc.ht);

 	lock(&procalloc);

-	p->pidhash = procalloc.ht[h];

-	procalloc.ht[h] = p;

+Retry:

+	pid = incref(&ref) & 0x7FFFFFFF;

+	if(pid == 0)

+		goto Retry;

+	h = pid % nelem(procalloc.ht);

+	for(x = procalloc.ht[h]; x != nil; x = x->pidhash)

+		if(x->pid == pid)

+			goto Retry;

+	if(p){

+		p->pid = pid;

+		p->pidhash = procalloc.ht[h];

+		procalloc.ht[h] = p;

+	}

 	unlock(&procalloc);

+	return pid;

 }

 static void

-pidunhash(Proc *p)

+pidfree(Proc *p)

 {

 	int h;

 	Proc **l;

--- a/sys/src/9/port/sysproc.c

+++ b/sys/src/9/port/sysproc.c

@@ -78,7 +78,7 @@

 			closeegrp(oeg);

 		}

 		if(flag & RFNOTEG)

-			up->noteid = incref(&noteidalloc);

+			up->noteid = pidalloc(0);

 		return 0;

 	}