ref: 4308f6e7e6586e3a27aa46c4d54c434b8533b16d
dir: /sys/src/9/port/page.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
Palloc palloc;
void
pageinit(void)
{
int color, i, j;
Page *p;
Pallocmem *pm;
vlong m, v, u;
if(palloc.pages == nil){
ulong np;
np = 0;
for(i=0; i<nelem(palloc.mem); i++){
pm = &palloc.mem[i];
np += pm->npage;
}
palloc.pages = xalloc(np*sizeof(Page));
if(palloc.pages == nil)
panic("pageinit");
}
color = 0;
palloc.head = nil;
p = palloc.pages;
for(i=0; i<nelem(palloc.mem); i++){
pm = &palloc.mem[i];
for(j=0; j<pm->npage; j++){
memset(p, 0, sizeof *p);
p->pa = pm->base+j*BY2PG;
if(cankaddr(p->pa) && (KADDR(p->pa) == nil || KADDR(p->pa) == (void*)-BY2PG))
continue;
p->color = color;
color = (color+1)%NCOLOR;
pagechainhead(p);
p++;
}
}
palloc.user = p - palloc.pages;
u = palloc.user*BY2PG;
v = u + conf.nswap*BY2PG;
/* Paging numbers */
swapalloc.highwater = (palloc.user*5)/100;
swapalloc.headroom = swapalloc.highwater + (swapalloc.highwater/4);
m = 0;
for(i=0; i<nelem(conf.mem); i++)
if(conf.mem[i].npage)
m += conf.mem[i].npage*BY2PG;
m += PGROUND(end - (char*)KTZERO);
print("%lldM memory: ", (m+1024*1024-1)/(1024*1024));
print("%lldM kernel data, ", (m-u+1024*1024-1)/(1024*1024));
print("%lldM user, ", u/(1024*1024));
print("%lldM swap\n", v/(1024*1024));
}
void
pagechainhead(Page *p)
{
p->next = palloc.head;
palloc.head = p;
palloc.freecount++;
}
void
pagechaindone(void)
{
if(palloc.pwait[0].p != nil && wakeup(&palloc.pwait[0]) != nil)
return;
if(palloc.pwait[1].p != nil)
wakeup(&palloc.pwait[1]);
}
static void
freepages(Page *head, Page *tail, ulong np)
{
lock(&palloc);
tail->next = palloc.head;
palloc.head = head;
palloc.freecount += np;
pagechaindone();
unlock(&palloc);
}
ulong
pagereclaim(Image *i, ulong pages)
{
Page **h, **l, **x, *p;
Page *fh, *ft;
ulong np;
if(pages == 0)
return 0;
lock(i);
if(i->pgref == 0){
unlock(i);
return 0;
}
incref(i);
np = 0;
fh = ft = nil;
for(h = i->pghash; h < &i->pghash[PGHSIZE]; h++){
l = h;
x = nil;
for(p = *l; p != nil; p = p->next){
if(p->ref == 0)
x = l;
l = &p->next;
}
if(x == nil)
continue;
p = *x;
*x = p->next;
p->next = nil;
p->image = nil;
p->daddr = ~0;
i->pgref--;
decref(i);
if(fh == nil)
fh = p;
else
ft->next = p;
ft = p;
if(++np >= pages)
break;
}
unlock(i);
putimage(i);
if(np > 0)
freepages(fh, ft, np);
return np;
}
static int
ispages(void*)
{
return palloc.freecount > swapalloc.highwater || up->noswap && palloc.freecount > 0;
}
Page*
newpage(int clear, Segment **s, uintptr va)
{
Page *p, **l;
KMap *k;
int color;
lock(&palloc);
while(!ispages(nil)){
unlock(&palloc);
if(s != nil)
qunlock(*s);
if(!waserror()){
Rendezq *q;
q = &palloc.pwait[!up->noswap];
eqlock(q);
if(!waserror()){
kickpager();
sleep(q, ispages, nil);
poperror();
}
qunlock(q);
poperror();
}
/*
* If called from fault and we lost the segment from
* underneath don't waste time allocating and freeing
* a page. Fault will call newpage again when it has
* reacquired the segment locks
*/
if(s != nil){
*s = nil;
return nil;
}
lock(&palloc);
}
/* First try for our colour */
color = getpgcolor(va);
l = &palloc.head;
for(p = *l; p != nil; p = p->next){
if(p->color == color)
break;
l = &p->next;
}
if(p == nil) {
l = &palloc.head;
p = *l;
}
*l = p->next;
p->next = nil;
palloc.freecount--;
unlock(&palloc);
p->ref = 1;
p->va = va;
p->modref = 0;
p->txtflush = 0;
if(clear) {
k = kmap(p);
memset((void*)VA(k), 0, BY2PG);
kunmap(k);
}
return p;
}
void
putpage(Page *p)
{
if(onswap(p)) {
putswap(p);
return;
}
if(p->image != nil) {
decref(p);
return;
}
if(decref(p) == 0)
freepages(p, p, 1);
}
void
copypage(Page *f, Page *t)
{
KMap *ks, *kd;
ks = kmap(f);
kd = kmap(t);
memmove((void*)VA(kd), (void*)VA(ks), BY2PG);
kunmap(ks);
kunmap(kd);
}
void
cachepage(Page *p, Image *i)
{
Page **h;
lock(i);
p->image = i;
h = &PGHASH(i, p->daddr);
p->next = *h;
*h = p;
incref(i);
i->pgref++;
unlock(i);
}
void
uncachepage(Page *p)
{
Page **l, *x;
Image *i;
i = p->image;
if(i == nil)
return;
lock(i);
if(p->image != i){
unlock(i);
return;
}
l = &PGHASH(i, p->daddr);
for(x = *l; x != nil; x = x->next) {
if(x == p){
*l = p->next;
p->next = nil;
p->image = nil;
p->daddr = ~0;
i->pgref--;
unlock(i);
putimage(i);
return;
}
l = &x->next;
}
unlock(i);
}
Page*
lookpage(Image *i, uintptr daddr)
{
Page *p, **h, **l;
lock(i);
l = h = &PGHASH(i, daddr);
for(p = *l; p != nil; p = p->next){
if(p->daddr == daddr){
*l = p->next;
p->next = *h;
*h = p;
incref(p);
unlock(i);
return p;
}
l = &p->next;
}
unlock(i);
return nil;
}
void
cachedel(Image *i, uintptr daddr)
{
Page *p;
while((p = lookpage(i, daddr)) != nil){
uncachepage(p);
putpage(p);
}
}
Pte*
ptecpy(Pte *old)
{
Pte *new;
Page **src, **dst;
new = ptealloc();
dst = &new->pages[old->first-old->pages];
new->first = dst;
for(src = old->first; src <= old->last; src++, dst++)
if(*src != nil) {
if(onswap(*src))
dupswap(*src);
else
incref(*src);
new->last = dst;
*dst = *src;
}
return new;
}
Pte*
ptealloc(void)
{
Pte *new;
new = smalloc(sizeof(Pte));
new->first = &new->pages[PTEPERTAB];
new->last = new->pages;
return new;
}
void
freepte(Segment *s, Pte *p)
{
Page **pg, **pe;
pg = p->first;
pe = p->last;
switch(s->type&SG_TYPE) {
case SG_PHYSICAL:
while(pg <= pe){
if(*pg != nil && decref(*pg) == 0)
free(*pg);
pg++;
}
break;
default:
while(pg <= pe){
if(*pg != nil)
putpage(*pg);
pg++;
}
}
free(p);
}
ulong
pagenumber(Page *p)
{
return p-palloc.pages;
}
void
checkpagerefs(void)
{
int s;
ulong i, np, nwrong;
ulong *ref;
np = palloc.user;
ref = malloc(np*sizeof ref[0]);
if(ref == nil){
print("checkpagerefs: out of memory\n");
return;
}
/*
* This may not be exact if there are other processes
* holding refs to pages on their stacks. The hope is
* that if you run it on a quiescent system it will still
* be useful.
*/
s = splhi();
lock(&palloc);
countpagerefs(ref, 0);
portcountpagerefs(ref, 0);
nwrong = 0;
for(i=0; i<np; i++){
if(palloc.pages[i].ref != ref[i]){
iprint("page %#p ref %ld actual %lud\n",
palloc.pages[i].pa, palloc.pages[i].ref, ref[i]);
ref[i] = 1;
nwrong++;
}else
ref[i] = 0;
}
countpagerefs(ref, 1);
portcountpagerefs(ref, 1);
iprint("%lud mistakes found\n", nwrong);
unlock(&palloc);
splx(s);
}
void
portcountpagerefs(ulong *ref, int print)
{
ulong i, j, k, ns, n;
Page **pg, *entry;
Proc *p;
Pte *pte;
Segment *s;
/*
* Pages in segments. s->mark avoids double-counting.
*/
n = 0;
ns = 0;
for(i=0; i<conf.nproc; i++){
p = proctab(i);
for(j=0; j<NSEG; j++){
s = p->seg[j];
if(s != nil)
s->mark = 0;
}
}
for(i=0; i<conf.nproc; i++){
p = proctab(i);
for(j=0; j<NSEG; j++){
s = p->seg[j];
if(s == nil || s->mark++)
continue;
if((s->type&SG_TYPE) == SG_PHYSICAL)
continue;
ns++;
for(k=0; k<s->mapsize; k++){
pte = s->map[k];
if(pte == nil)
continue;
for(pg = pte->first; pg <= pte->last; pg++){
entry = *pg;
if(pagedout(entry))
continue;
if(print){
if(ref[pagenumber(entry)])
iprint("page %#p in segment %#p\n", entry->pa, s);
continue;
}
if(ref[pagenumber(entry)]++ == 0)
n++;
}
}
}
}
if(!print){
iprint("%lud pages in %lud segments\n", n, ns);
for(i=0; i<conf.nproc; i++){
p = proctab(i);
for(j=0; j<NSEG; j++){
s = p->seg[j];
if(s == nil)
continue;
if(s->ref != s->mark){
iprint("segment %#p (used by proc %lud pid %lud) has bad ref count %lud actual %lud\n",
s, i, p->pid, s->ref, s->mark);
}
}
}
}
}