On Mon, Jun 25, 2012 at 09:30:47AM -0400, Vivek Goyal wrote: > In slice_expired() we can probably put a BUG_ON() which checks following. > > BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list) && (cfqq->queued[0] || cfqq->queued[1]));
Nit: Please use WARN_ON_ONCE() instead. Multi-sec stalls tend to be better than panic. :)