V5/usr/sys/ken/slp.c

#
/*
 *	Copyright 1973 Bell Telephone Laboratories Inc
 */

#include "../param.h"
#include "../user.h"
#include "../proc.h"
#include "../text.h"
#include "../systm.h"
#include "../file.h"
#include "../inode.h"
#include "../buf.h"

#define	PS	0177776
struct	{
	int integ;
};

sleep(chan, pri)
{
	register *rp, s;

	u.u_dsleep = 0;
	s = PS->integ;
	rp = u.u_procp;
	if(pri >= 0) {
		if(issig())
			goto psig;
		rp->p_wchan = chan;
		rp->p_stat = SWAIT;
		rp->p_pri = pri;
		spl0();
		if(runin != 0) {
			runin = 0;
			wakeup(&runin);
		}
		swtch();
		if(issig()) {
		psig:
			aretu(u.u_qsav);
			return;
		}
	} else {
		rp->p_wchan = chan;
		rp->p_stat = SSLEEP;
		rp->p_pri = pri;
		spl0();
		swtch();
	}
	PS->integ = s;
}

wakeup(chan)
{
	register struct proc *p;
	register n, c;

loop:
	c = chan;
	n = 0;
	for(p = &proc[0]; p < &proc[NPROC]; p++)
		if(p->p_wchan == c) {
			if(runout!=0 && (p->p_flag&SLOAD)==0) {
				runout = 0;
				n++;
			}
			p->p_wchan = 0;
			p->p_stat = SRUN;
			runrun++;
		}
	if(n) {
		chan = &runout;
		goto loop;
	}
}

sched()
{
	struct proc *p1;
	register struct proc *rp;
	register a, n;

	/*
	 * find user to swap in
	 * of users ready, select one out longest
	 */

	goto loop;

sloop:
	runin++;
	sleep(&runin, PSWP);

loop:
	spl6();
	n = -1;
	for(rp = &proc[0]; rp < &proc[NPROC]; rp++)
	if(rp->p_stat==SRUN && (rp->p_flag&SLOAD)==0 &&
	    rp->p_time > n) {
		p1 = rp;
		n = rp->p_time;
	}
	if(n == -1) {
		runout++;
		sleep(&runout, PSWP);
		goto loop;
	}

	/*
	 * see if there is core for that process
	 */

	spl0();
	rp = p1;
	a = rp->p_size;
	if((rp=rp->p_textp) != NULL)
		if(rp->x_ccount == 0)
			a =+ rp->x_size;
	if((a=malloc(coremap, a)) != NULL)
		goto found2;

	/*
	 * none found,
	 * look around for easy core
	 */

	spl6();
	for(rp = &proc[0]; rp < &proc[NPROC]; rp++)
	if((rp->p_flag&(SSYS|SLOCK|SLOAD))==SLOAD &&
	    rp->p_stat == SWAIT)
		goto found1;

	/*
	 * no easy core,
	 * if this process is deserving,
	 * look around for
	 * oldest process in core
	 */

	if(n < 3)
		goto sloop;
	n = -1;
	for(rp = &proc[0]; rp < &proc[NPROC]; rp++)
	if((rp->p_flag&(SSYS|SLOCK|SLOAD))==SLOAD &&
	   (rp->p_stat==SRUN || rp->p_stat==SSLEEP) &&
	    rp->p_time > n) {
		p1 = rp;
		n = rp->p_time;
	}
	if(n < 2)
		goto sloop;
	rp = p1;

	/*
	 * swap user out
	 */

found1:
	spl0();
	rp->p_flag =& ~SLOAD;
	xswap(rp, 1, 0);
	goto loop;

	/*
	 * swap user in
	 */

found2:
	if((rp=p1->p_textp) != NULL) {
		if(rp->x_ccount == 0) {
			if(swap(rp->x_daddr, a, rp->x_size, B_READ))
				goto swaper;
			rp->x_caddr = a;
			a =+ rp->x_size;
		}
		rp->x_ccount++;
	}
	rp = p1;
	if(swap(rp->p_addr, a, rp->p_size, B_READ))
		goto swaper;
	mfree(swapmap, (rp->p_size+7)/8, rp->p_addr);
	rp->p_addr = a;
	rp->p_flag =| SLOAD;
	rp->p_time = 0;
	goto loop;

swaper:
	panic("swap error");
}

swtch()
{
	static int *p;
	register i, n;
	register struct proc *rp;

	if(p == NULL)
		p = &proc[0];
	savu(u.u_rsav);
	retu(proc[0].p_addr);

loop:
	rp = p;
	p = NULL;
	n = 127;
	for(i=0; i<NPROC; i++) {
		rp++;
		if(rp >= &proc[NPROC])
			rp = &proc[0];
		if(rp->p_stat==SRUN && (rp->p_flag&SLOAD)!=0) {
			if(rp->p_pri < n) {
				p = rp;
				n = rp->p_pri;
			}
		}
	}
	if(p == NULL) {
		p = rp;
		idle();
		goto loop;
	}
	rp = p;
	retu(rp->p_addr);
	sureg();
	if(rp->p_flag&SSWAP) {
		rp->p_flag =& ~SSWAP;
		aretu(u.u_ssav);
	}
	return(1);
}

newproc()
{
	int a1, a2;
	struct proc *p, *up;
	register struct proc *rpp;
	register *rip, n;

	for(rpp = &proc[0]; rpp < &proc[NPROC]; rpp++)
		if(rpp->p_stat == NULL)
			goto found;
	panic("no procs");

found:
	/*
	 * make proc entry for new proc
	 */

	p = rpp;
	rip = u.u_procp;
	up = rip;
	rpp->p_stat = SRUN;
	rpp->p_flag = SLOAD;
	rpp->p_uid = rip->p_uid;
	rpp->p_ttyp = rip->p_ttyp;
	rpp->p_textp = rip->p_textp;
	rpp->p_pid = ++mpid;
	rpp->p_ppid = rip->p_pid;
	rpp->p_time = 0;

	/*
	 * make duplicate entries
	 * where needed
	 */

	for(rip = &u.u_ofile[0]; rip < &u.u_ofile[NOFILE];)
		if((rpp = *rip++) != NULL)
			rpp->f_count++;
	if((rpp=up->p_textp) != NULL) {
		rpp->x_count++;
		rpp->x_ccount++;
	}
	u.u_cdir->i_count++;

	/*
	 * swap out old process
	 * to make image of new proc
	 */

	savu(u.u_rsav);
	rpp = p;
	u.u_procp = rpp;
	rip = up;
	n = rip->p_size;
	a1 = rip->p_addr;
	rpp->p_size = n;
	a2 = malloc(coremap, n);
	if(a2 == NULL) {
		rip->p_stat = SIDL;
		rpp->p_addr = a1;
		savu(u.u_ssav);
		xswap(rpp, 0, 0);
		rpp->p_flag =| SSWAP;
		rip->p_stat = SRUN;
	} else {
		rpp->p_addr = a2;
		while(n--)
			copyseg(a1++, a2++);
	}
	u.u_procp = rip;
	return(0);
}

expand(newsize)
{
	int i, n;
	register *p, a1, a2;

	p = u.u_procp;
	n = p->p_size;
	p->p_size = newsize;
	a1 = p->p_addr;
	if(n >= newsize) {
		mfree(coremap, n-newsize, a1+newsize);
		return;
	}
	savu(u.u_rsav);
	a2 = malloc(coremap, newsize);
	if(a2 == NULL) {
		savu(u.u_ssav);
		xswap(p, 1, n);
		p->p_flag =| SSWAP;
		swtch();
		/* no return */
	}
	p->p_addr = a2;
	for(i=0; i<n; i++)
		copyseg(a1+i, a2++);
	mfree(coremap, n, a1);
	retu(p->p_addr);
	sureg();
}