Image*
attachimage(int type, Chan *c, ulong base, ulong len)
{
Image *i, **l;
lock(&imagealloc);
/*
* Search the image cache for remains of the text from a previous
* or currently running incarnation
*/
for(i = ihash(c->qid.path); i; i = i->hash) {
if(c->qid.path == i->qid.path) {
lock(i);
if(eqqid(c->qid, i->qid) &&
eqqid(c->mqid, i->mqid) &&
c->mchan == i->mchan &&
c->type == i->type) {
goto found;
}
unlock(i);
}
}
/*
* imagereclaim dumps pages from the free list which are cached by image
* structures. This should free some image structures.
*/
while(!(i = imagealloc.free)) {
unlock(&imagealloc);
imagereclaim();
if(!imagealloc.free){
freebroken(); /* can use the memory */
resrcwait("no image after reclaim");
}
lock(&imagealloc);
}
imagealloc.free = i->next;
lock(i);
incref(c);
c->flag &= ~CCACHE;
i->c = c;
i->type = c->type;
i->qid = c->qid;
i->mqid = c->mqid;
i->mchan = c->mchan;
l = &ihash(c->qid.path);
i->hash = *l;
*l = i;
found:
unlock(&imagealloc);
if(i->s == 0) {
i->ref++;
if(waserror()) {
unlock(i);
putimage(i);
nexterror();
}
i->s = newseg(type, base, len);
i->s->image = i;
poperror();
}
else
incref(i->s);
return i;
}
static void
pager(void *junk)
{
int i;
Segment *s;
Proc *p, *ep;
if(waserror())
panic("pager: os error\n");
p = proctab(0);
ep = &p[conf.nproc];
loop:
up->psstate = "Idle";
sleep(&swapalloc.r, needpages, 0);
print("uh oh. someone woke the pager\n");
while(needpages(junk)) {
if(swapimage.c) {
p++;
if(p >= ep)
p = proctab(0);
if(p->state == Dead || p->noswap)
continue;
if(!canqlock(&p->seglock))
continue; /* process changing its segments */
for(i = 0; i < NSEG; i++) {
if(!needpages(junk)){
qunlock(&p->seglock);
goto loop;
}
if((s = p->seg[i])) {
switch(s->type&SG_TYPE) {
default:
break;
case SG_TEXT:
pageout(p, s);
break;
case SG_DATA:
case SG_BSS:
case SG_STACK:
case SG_SHARED:
up->psstate = "Pageout";
pageout(p, s);
if(ioptr != 0) {
up->psstate = "I/O";
executeio();
}
break;
}
}
}
qunlock(&p->seglock);
}
else {
print("out of physical memory; no swap configured\n");
if(!cpuserver || freebroken() == 0)
killbig("out of memory");
/* Emulate the old system if no swap channel */
tsleep(&up->sleep, return0, 0, 5000);
wakeup(&palloc.r);
}
}
goto loop;
}
