diff options
Diffstat (limited to 'block/blk-throttle.c')
| -rw-r--r-- | block/blk-throttle.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 381b09bb562..a89043a3caa 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -168,7 +168,15 @@ static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td, * tree of blkg (instead of traversing through hash list all * the time. */ - tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key)); + + /* + * This is the common case when there are no blkio cgroups. + * Avoid lookup in this case + */ + if (blkcg == &blkio_root_cgroup) + tg = &td->root_tg; + else + tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key)); /* Fill in device details for root group */ if (tg && !tg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |