Quoting David Hildenbrand (2023-07-27 09:41:51)
> On 10.05.23 14:18, Nico Boehr wrote:
> > The gmap notifier is called for changes in table entries with the
> > notifier bit set. To diagnose performance issues, it can be useful to
> > see what causes certain changes in the gmap.
> >
> > Hence, add a tracepoint in the gmap notifier.
> >
> > Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
> > ---
> > arch/s390/kvm/kvm-s390.c | 2 ++
> > arch/s390/kvm/trace-s390.h | 23 +++++++++++++++++++++++
> > 2 files changed, 25 insertions(+)
> >
> > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > index ded4149e145b..e8476c023b07 100644
> > --- a/arch/s390/kvm/kvm-s390.c
> > +++ b/arch/s390/kvm/kvm-s390.c
> > @@ -3982,6 +3982,8 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start,
> > unsigned long prefix;
> > unsigned long i;
> >
> > + trace_kvm_s390_gmap_notifier(start, end, gmap_is_shadow(gmap));
> > +
> > if (gmap_is_shadow(gmap))
> > return;
> > if (start >= 1UL << 31)
> > diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h
> > index 6f0209d45164..5dabd0b64d6e 100644
> > --- a/arch/s390/kvm/trace-s390.h
> > +++ b/arch/s390/kvm/trace-s390.h
> > @@ -333,6 +333,29 @@ TRACE_EVENT(kvm_s390_airq_suppressed,
> > __entry->id, __entry->isc)
> > );
> >
> > +/*
> > + * Trace point for gmap notifier calls.
> > + */
> > +TRACE_EVENT(kvm_s390_gmap_notifier,
> > + TP_PROTO(unsigned long start, unsigned long end, unsigned int shadow),
> > + TP_ARGS(start, end, shadow),
> > +
> > + TP_STRUCT__entry(
> > + __field(unsigned long, start)
> > + __field(unsigned long, end)
> > + __field(unsigned int, shadow)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->start = start;
> > + __entry->end = end;
> > + __entry->shadow = shadow;
> > + ),
> > +
> > + TP_printk("gmap notified (start:0x%lx end:0x%lx shadow:%d)",
> > + __entry->start, __entry->end, __entry->shadow)
> > + );
> > +
> >
> > #endif /* _TRACE_KVMS390_H */
> >
>
> In the context of vsie, I'd have thought you'd be tracing
> kvm_s390_vsie_gmap_notifier() instead.
Right, I can change that if you / others have a preference for that.
