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dm bufio: don't take the lock in dm_bufio_shrink_count 

dm_bufio_shrink_count() is called from do_shrink_slab to find out how many
freeable objects are there. The reported value doesn't have to be precise,
so we don't need to take the dm-bufio lock.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2016-11-23 16:52:01 -05:00 committed by Mike Snitzer
parent 9ea61cac0b
commit d12067f428
1 changed files with 2 additions and 11 deletions
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13
drivers/md/dm-bufio.c
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@ -1588,18 +1588,9 @@ dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
static unsigned long
dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
{
struct dm_bufio_client *c;
unsigned long count;
struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker);
c = container_of(shrink, struct dm_bufio_client, shrinker);
if (sc->gfp_mask & __GFP_FS)
dm_bufio_lock(c);
else if (!dm_bufio_trylock(c))
return 0;
count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY];
dm_bufio_unlock(c);
return count;
return ACCESS_ONCE(c->n_buffers[LIST_CLEAN]) + ACCESS_ONCE(c->n_buffers[LIST_DIRTY]);
}
/*