/*
* called with s->lk locked
*/
void
mfreeseg(Segment *s, ulong start, int pages)
{
int i, j, size;
ulong soff;
Page *pg;
Page *list;
soff = start-s->base;
j = (soff&(PTEMAPMEM-1))/BY2PG;
size = s->mapsize;
list = nil;
for(i = soff/PTEMAPMEM; i < size; i++) {
if(pages <= 0)
break;
if(s->map[i] == 0) {
pages -= PTEPERTAB-j;
j = 0;
continue;
}
while(j < PTEPERTAB) {
pg = s->map[i]->pages[j];
/*
* We want to zero s->map[i]->page[j] and putpage(pg),
* but we have to make sure other processors flush the
* entry from their TLBs before the page is freed.
* We construct a list of the pages to be freed, zero
* the entries, then (below) call procflushseg, and call
* putpage on the whole list.
*
* Swapped-out pages don't appear in TLBs, so it's okay
* to putswap those pages before procflushseg.
*/
if(pg){
if(onswap(pg))
putswap(pg);
else{
pg->next = list;
list = pg;
}
s->map[i]->pages[j] = 0;
}
if(--pages == 0)
goto out;
j++;
}
j = 0;
}
out:
/* flush this seg in all other processes */
if(s->ref > 1)
procflushseg(s);
/* free the pages */
for(pg = list; pg != nil; pg = list){
list = list->next;
putpage(pg);
}
}
void
putpage(Page *p)
{
if(onswap(p)) {
putswap(p);
return;
}
lock(&palloc);
lock(p);
if(p->ref == 0)
panic("putpage");
if(--p->ref > 0) {
unlock(p);
unlock(&palloc);
return;
}
if(p->image && p->image != &swapimage)
pagechaintail(p);
else
pagechainhead(p);
if(palloc.r.p != 0)
wakeup(&palloc.r);
unlock(p);
unlock(&palloc);
}
