diff options
| author | Jens Axboe <axboe@fb.com> | 2015-04-17 16:23:59 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-05-05 13:32:49 -0600 |
| commit | dac56212e8127dbc0bff7be35c508bc280213309 (patch) | |
| tree | a1a066d7f6deb7d66403137b8edafb394ce0ca6a /fs/btrfs/volumes.c | |
| parent | c4cf5261f8bffd9de132b50660a69148e7575bd6 (diff) | |
bio: skip atomic inc/dec of ->bi_cnt for most use cases
Struct bio has a reference count that controls when it can be freed.
Most uses cases is allocating the bio, which then returns with a
single reference to it, doing IO, and then dropping that single
reference. We can remove this atomic_dec_and_test() in the completion
path, if nobody else is holding a reference to the bio.
If someone does call bio_get() on the bio, then we flag the bio as
now having valid count and that we must properly honor the reference
count when it's being put.
Tested-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 96aebf3bcd5b..8e8d1d1e28a5 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -345,7 +345,7 @@ loop_lock: waitqueue_active(&fs_info->async_submit_wait)) wake_up(&fs_info->async_submit_wait); - BUG_ON(atomic_read(&cur->bi_cnt) == 0); + BUG_ON(atomic_read(&cur->__bi_cnt) == 0); /* * if we're doing the sync list, record that our |