/*
* Called from switchin when we discover that we want to run
* a swapped process. As all our processes are the same size
* for now this remains fairly simple.
*/
void swapper(ptptr p)
{
pagemap_alloc(p); /* May cause a swapout */
#ifdef DEBUG
kprintf("Swapping in %x (page %d), utab.ptab %x\n", p, p->p_page,
udata.u_ptab);
#endif
swapin(p);
#ifdef DEBUG
kprintf("Swapped in %x (page %d), udata.ptab %x\n",
p, p->p_page, udata.u_ptab);
#endif
}
ptptr ptab_alloc(void)
{
ptptr p, newp;
irqflags_t irq;
newp = NULL;
udata.u_error = EAGAIN;
irq = di();
for (p = ptab; p < ptab_end; p++)
if (p->p_status == P_EMPTY) {
newp = p;
break;
}
if (newp) { /* found a slot? */
/* zero process structure */
memset(newp, 0, sizeof(struct p_tab));
/* select a unique pid */
while (newp->p_pid == 0) {
if (nextpid++ > MAXPID)
nextpid = 20;
newp->p_pid = nextpid;
for (p = ptab; p < ptab_end; p++)
if (p->p_status != P_EMPTY
&& p->p_pid == nextpid) {
newp->p_pid = 0; /* try again */
break;
}
}
newp->p_top = udata.u_top;
if (pagemap_alloc(newp) == 0) {
newp->p_status = P_FORKING;
nproc++;
} else {
udata.u_error = ENOMEM;
newp = NULL;
}
newp->p_pgrp = udata.u_ptab->p_pgrp;
memcpy(newp->p_name, udata.u_ptab->p_name, sizeof(newp->p_name));
}
irqrestore(irq);
if (newp)
udata.u_error = 0;
return newp;
}
/*
* Called from switchin when we discover that we want to run
* a swapped process. We let pagemap_alloc cause any needed swap
* out of idle processes.
*/
void swapper(ptptr p)
{
uint16_t map = p->p_page2;
pagemap_alloc(p); /* May cause a swapout. May also destroy
the old value of p->page2 */
#ifdef DEBUG
kprintf("Swapping in %x (page %d), utab.ptab %x\n", p, p->p_page,
udata.u_ptab);
#endif
swapin(p, map);
swapmap_add(map);
#ifdef DEBUG
kprintf("Swapped in %x (page %d), udata.ptab %x\n",
p, p->p_page, udata.u_ptab);
#endif
}