On Wed, Dec 18, 2019 at 03:19:40PM +0800, Ming Lei wrote: > Scheduler runqueue maintains its own software clock that is periodically > synchronised with hardware. Export this clock so that it can be used > by interrupt flood detection for saving the cost of reading from hardware. But you don't have much, if any, guarantees the thing gets updated. > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 90e4b00ace89..03e2e3c36067 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -219,6 +219,11 @@ void update_rq_clock(struct rq *rq) > update_rq_clock_task(rq, delta); > } > > +u64 sched_local_rq_clock(void) > +{ > + return this_rq()->clock; > +} > +EXPORT_SYMBOL_GPL(sched_local_rq_clock); Also, more NAK, you're exporting a variant of __rq_clock_broken(). (which, now that I git-grep for it, has become unused, good!)