On Mon, Mar 22, 2021 at 04:12:17PM +0800, Li, Aubrey wrote: > > But suppose there is an imbalance; then this cookie crud can forever > > stall balance. > > > > Imagine this cpu running a while(1); with a uniqie cookie on, then it > > will _never_ accept other tasks == BAD. > > > > How about putting the following check in sched_core_cookie_match()? > > + /* > + * Ignore cookie match if there is a big imbalance between the src rq > + * and dst rq. > + */ > + if ((src_rq->cfs.h_nr_running - rq->cfs.h_nr_running) > 1) > + return true;
That's just tinkering... cookie matching should not also look at imbalance of any kind. > Do you have any suggestions before we drop it? Yeah, how about you make it part of task_hot() ? Have task_hot() refuse migration it the cookie doesn't match. task_hot() is a hint and will get ignored when appropriate.
