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kernel: duppage cleanup

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remove the sched() call and retry loop from duppage() and just
drop the page lock, then reacquire it after lock(&palloc).
This commit is contained in:
cinap_lenrek 2012-10-16 16:10:26 +02:00
parent 45b99937be
commit fcacce0f2f
1 changed files with 8 additions and 22 deletions
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30
sys/src/9/port/page.c
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@ -264,29 +264,11 @@ auxpage(void)
return p;
}
static int dupretries = 15000;
void
duppage(Page *p) /* Always call with p locked */
{
Page *np;
int color;
int retries;
retries = 0;
retry:
/* don't dup pages that are shared or have no image */
if(p->ref != 1 || p->image == nil || p->image->notext)
return;
if(retries++ > dupretries){
print("duppage %d, up %p\n", retries, up);
dupretries += 100;
if(dupretries > 100000)
panic("duppage");
uncachepage(p);
return;
}
/*
* normal lock ordering is to call
@ -295,14 +277,18 @@ retry:
* our locks and try again. as the page
* is from the image cache, this might
* let someone else come in and grab it
* so we check page ref above.
* so we check page ref below.
*/
if(!canlock(&palloc)){
unlock(p);
if(up)
sched();
lock(&palloc);
lock(p);
goto retry;
}
/* don't dup pages that are shared or have no image */
if(p->ref != 1 || p->image == nil || p->image->notext){
unlock(&palloc);
return;
}
/* No freelist cache when memory is very low */