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 <[email protected]> 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 <[email protected]>
> > Signed-off-by: Paul E. McKenney <[email protected]>
> >
> > ---
> >
> > 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++;
> > }
