Messages in this thread | | | Date | Sat, 27 Jun 2020 14:46:29 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH tick-sched] Clarify "NOHZ: local_softirq_pending" warning |
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On Sat, Jun 27, 2020 at 02:02:15PM -0700, Andy Lutomirski wrote: > On Fri, Jun 26, 2020 at 2:05 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > Currently, can_stop_idle_tick() prints "NOHZ: local_softirq_pending HH" > > (where "HH" is the hexadecimal softirq vector number) when one or more > > non-RCU softirq handlers are still enablded when checking to stop the > > scheduler-tick interrupt. This message is not as enlightening as one > > might hope, so this commit changes it to "NOHZ tick-stop error: Non-RCU > > local softirq work is pending, handler #HH. > > Thank you! It would be even better if it would explain *why* the > problem happened, but I suppose this code doesn't actually know.
Glad to help!
To your point, is it possible to bisect the appearance of this message, or is it as usual non-reproducible? (Hey, had to ask!)
Thanx, Paul
> --Andy > > > > > Reported-by: Andy Lutomirski <luto@kernel.org> > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > --- > > > > tick-sched.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > > index f0199a4..349a25a 100644 > > --- a/kernel/time/tick-sched.c > > +++ b/kernel/time/tick-sched.c > > @@ -927,7 +927,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) > > > > if (ratelimit < 10 && > > (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) { > > - pr_warn("NOHZ: local_softirq_pending %02x\n", > > + pr_warn("NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #%02x\n", > > (unsigned int) local_softirq_pending()); > > ratelimit++; > > }
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