Re: 2.6.19-rc6-mm1

Mariusz Kozlowski
2006-11-23T19:23:25Z

Hello,

> > Hmmm ... didn't apply cleanly.
> >
> > patching file kernel/tsacct.c
> > Hunk #1 FAILED at 97.
> > 1 out of 1 hunk FAILED -- saving rejects to file kernel/tsacct.c.rej
>
> I think your local tree is not clean.

Nope. I've seen it on three boxes.

> > Anyway this is what I get on my laptop:
> >
> > =================================
> > [ INFO: inconsistent lock state ]
> > 2.6.19-rc6-mm1 #1
> > ---------------------------------
> > inconsistent {hardirq-on-R} -> {in-hardirq-W} usage.
>
> hm, nested read_lock_irq()+read_unlock_irq() in the readahead code..

I guess what you meant was sth like the patch below. That helped. Thanks.

--- linux-2.6.19-rc6-mm1-a/mm/readahead.c 2006-11-23 20:03:53.000000000 +0100
+++ linux-2.6.19-rc6-mm1-b/mm/readahead.c 2006-11-23 19:57:26.000000000 +0100
@@ -1227,10 +1227,10 @@ static inline unsigned long inactive_pag

/*
* Count/estimate cache hits in range [begin, end).
- * The estimation is simple and optimistic.
+ * The estimation is simple and optimistic. The caller must hold tree_lock.
*/
#define CACHE_HIT_HASH_KEY 29 /* some prime number */
-static int count_cache_hit(struct address_space *mapping,
+static int __count_cache_hit(struct address_space *mapping,
pgoff_t begin, pgoff_t end)
{
int size = end - begin;
@@ -1243,14 +1243,12 @@ static int count_cache_hit(struct addres
* behavior guarantees a readahead when (size < ra_max) and
* (readahead_hit_rate >= 8).
*/
- read_lock_irq(&mapping->tree_lock);
for (i = 0; i < 8;) {
struct page *page = radix_tree_lookup(&mapping->page_tree,
begin + size * ((i++ * CACHE_HIT_HASH_KEY) & 7) / 8);
if (inactive_page_refcnt(page) >= PAGE_REFCNT_1 && ++count >= 2)
break;
}
- read_unlock_irq(&mapping->tree_lock);

return size * count / i;
}
@@ -1282,7 +1280,7 @@ static unsigned long count_history_pages
*/
if (!(ra->flags & RA_FLAG_NFSD)) {
unsigned long hit_rate = max(readahead_hit_rate, 1);
- if (count_cache_hit(mapping, head, offset) * hit_rate < count)
+ if (__count_cache_hit(mapping, head, offset) * hit_rate < count)
count = 0;
}

--
Regards,

Mariusz Kozlowski