On Tue, 28 Mar 2017 18:44:59 +0200 Peter Zijlstra <pet...@infradead.org> wrote:
> On Tue, Mar 28, 2017 at 10:46:00AM -0400, Steven Rostedt wrote: > > On Tue, 28 Mar 2017 07:35:38 +0100 > > Dietmar Eggemann <dietmar.eggem...@arm.com> wrote: > > > > > /* This part must be outside protection */ > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > index 03adf9fb48b1..ac19ab6ced8f 100644 > > > --- a/kernel/sched/fair.c > > > +++ b/kernel/sched/fair.c > > > @@ -2950,6 +2950,9 @@ __update_load_avg(u64 now, int cpu, struct > > > sched_avg *sa, > > > sa->util_avg = sa->util_sum / LOAD_AVG_MAX; > > > } > > > > > > + if (cfs_rq) > > > + trace_sched_load_cfs_rq(cfs_rq); > > > + > > > > Please use TRACE_EVENT_CONDITION(), and test for cfs_rq not NULL. > > I too suggested that; but then I looked again at that code and we can > actually do this. cfs_rq can be constant propagated and the if > determined at build time. > > Its not immediately obvious from the current code; but if we do > something like the below, it should be clearer. > But why play games, and rely on the design of the code? A TRACE_EVENT_CONDTION() is more robust and documents that this tracepoint should not be called when cfs_rq is NULL. -- Steve
