On Tue, Mar 07, 2023 at 02:35:52PM +0000, Valentin Schneider wrote: > trace_ipi_raise() is unsuitable for generically tracing IPI sources due to > its "reason" argument being an uninformative string (on arm64 all you get > is "Function call interrupts" for SMP calls). > > Add a variant of it that exports a target cpumask, a callsite and a callback. > > Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx> > Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> > --- > include/trace/events/ipi.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h > index 0be71dad6ec03..b1125dc27682c 100644 > --- a/include/trace/events/ipi.h > +++ b/include/trace/events/ipi.h > @@ -35,6 +35,28 @@ TRACE_EVENT(ipi_raise, > TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason) > ); > > +TRACE_EVENT(ipi_send_cpumask, > + > + TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback), > + > + TP_ARGS(cpumask, callsite, callback), > + > + TP_STRUCT__entry( > + __cpumask(cpumask) > + __field(void *, callsite) > + __field(void *, callback) > + ), > + > + TP_fast_assign( > + __assign_cpumask(cpumask, cpumask_bits(cpumask)); > + __entry->callsite = (void *)callsite; > + __entry->callback = callback; > + ), > + > + TP_printk("cpumask=%s callsite=%pS callback=%pS", > + __get_cpumask(cpumask), __entry->callsite, __entry->callback) > +); Would it make sense to add a variant like: ipi_send_cpu() that records a single cpu instead of a cpumask. A lot of sites seems to do: cpumask_of(cpu) for that first argument, and it seems to me it is quite daft to have to memcpy a full multi-word cpumask in those cases. Remember, nr_possible_cpus > 64 is quite common these days.