Hi Peter, On Fri, 18 Nov 2016 15:23:59 +0100 Peter Zijlstra <pet...@infradead.org> wrote: [...] > u64 running_bw; > > static void add_running_bw(struct sched_dl_entity *dl_se, struct > dl_rq *dl_rq) { > u64 old = dl_rq->running_bw; > > dl_rq->running_bw += dl_se->dl_bw; > SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ > } > > static void sub_running_bw(struct sched_dl_entity *dl_se, struct > dl_rq *dl_rq) { > u64 old = dl_rq->running_bw; > > dl_rq->running_bw -= dl_se->dl_bw; > SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ > }
I wanted to change "SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */" into "if (SCHED_WARN_ON(...)) dl_rq->running_bw = 0" (to avoid using nonsensical "running_bw" values), but I see that "SCHED_WARN_ON()" cannot be used inside an if (this seems to be a difference respect to "SCHED_WARN()"). This is because of the definition used when CONFIG_SCHED_DEBUG is not defined (I noticed the issue when testing with random kernel configurations). Is this expected? If yes, what should I do in this case? Something like SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ if (dl_rq->running_bw > old) dl_rq->running_bw = 0; ? Or something else? Thanks, Luca