On Fri, Sep 07, 2018 at 09:51:04AM +0200, Vincent Guittot wrote: > It can happen that load_balance finds a busiest group and then a busiest rq > but the calculated imbalance is in fact null.
Cute. Does that happen often? > If the calculated imbalance is null, it's useless to try to find a busiest > rq as no task will be migrated and we can return immediately. > > This situation can happen with heterogeneous system or smp system when RT > tasks are decreasing the capacity of some CPUs. Is it the result of one of those "force_balance" conditions in find_busiest_group() ? Should we not fix that to then return NULL instead?
