From: Marcelo Tosatti <marcelo@conectiva.com.br>
Date: Tue, 25 Sep 2001 14:49:40 -0300 (BRT)
Do you really need to do this ?
if (unlikely(!spin_trylock(&pagecache_lock))) {
/* we hold the page lock so the page cannot go away from under us */
spin_unlock(&pagemap_lru_lock);
spin_lock(&pagecache_lock);
spin_lock(&pagemap_lru_lock);
}
Have you actually seen bad hold times of pagecache_lock by
shrink_caches() ?
Marcelo, this is needed because of the spin lock ordering rules.
The pagecache_lock must be obtained before the pagemap_lru_lock
or else deadlock is possible. The spin_trylock is an optimization.
Franks a lot,
David S. Miller
davem@redhat.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Sep 30 2001 - 21:00:33 EST