Re: 2.6.19-rc6-mm1

[Andrew Morton]

On Thu, 23 Nov 2006 12:23:48 +0100
Mariusz Kozlowski <m.kozlowski@xxxxxxxxxx> wrote:

> 
> 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.

> 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..

--- a/mm/readahead.c~readahead-context-based-method-locking-fix
+++ a/mm/readahead.c
@@ -1171,10 +1171,10 @@ 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;
@@ -1187,14 +1187,12 @@ 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;
 }
_

-
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