diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2016-11-23 16:52:01 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-11 16:03:51 +0200 |
| commit | 5be6e45d184c8a9dfa35626092b7a71e42ef5ee2 (patch) | |
| tree | 40fc2b8a82df2ab2bd998de8a5a50bbe312c33ec /drivers | |
| parent | bf4e6336ccbc57bb8898c6fadd904139dd9bd927 (diff) | |
dm bufio: don't take the lock in dm_bufio_shrink_count
commit d12067f428c037b4575aaeb2be00847fc214c24a upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-bufio.c | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 767b5c049736..b1d5fa0bc8f7 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1574,19 +1574,11 @@ 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; - unsigned long retain_target; - - 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; + struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker); + unsigned long count = READ_ONCE(c->n_buffers[LIST_CLEAN]) + + READ_ONCE(c->n_buffers[LIST_DIRTY]); + unsigned long retain_target = get_retain_buffers(c); - count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; - retain_target = get_retain_buffers(c); - dm_bufio_unlock(c); return (count < retain_target) ? 0 : (count - retain_target); } |