Re: [PATCH] mm: vmscan: drop zone id from kswapd tracepoints

[Yafang Shao <laoar.shao@gmail.com>]

On Wed, Mar 13, 2019 at 4:03 PM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Wed 13-03-19 12:36:53, Yafang Shao wrote:
> > The zid is meaningless to the user.
>
> This is quite bold statement. We do not know whether that is useful.
> Quite likely not. I would go with
>
> "It is not clear how is the zone id useful in kswapd tracepoints and the
> id itself is not really easy to process because it depends on the
> configuration (available zones). Let's drop the id for now. If somebody
> really needs that information the the zone name should be used instead."
>

Thanks for your improvements on the commit log :-)

> > If we really want to expose it, we'd better expose the zone type
> > (i.e. ZONE_NORMAL) intead of this number.
> > Per discussion with Michal, seems this zid is not so userful in kswapd
> > tracepoints, so we'd better drop it to avoid making noise.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
>
> Acked-by: Michal Hocko <mhocko@suse.com>
>
> > ---
> >  include/trace/events/vmscan.h | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
> > index a1cb913..d3f029f 100644
> > --- a/include/trace/events/vmscan.h
> > +++ b/include/trace/events/vmscan.h
> > @@ -73,7 +73,9 @@
> >               __entry->order  = order;
> >       ),
> >
> > -     TP_printk("nid=%d zid=%d order=%d", __entry->nid, __entry->zid, __entry->order)
> > +     TP_printk("nid=%d order=%d",
> > +             __entry->nid,
> > +             __entry->order)
> >  );
> >
> >  TRACE_EVENT(mm_vmscan_wakeup_kswapd,
> > @@ -96,9 +98,8 @@
> >               __entry->gfp_flags      = gfp_flags;
> >       ),
> >
> > -     TP_printk("nid=%d zid=%d order=%d gfp_flags=%s",
> > +     TP_printk("nid=%d order=%d gfp_flags=%s",
> >               __entry->nid,
> > -             __entry->zid,
> >               __entry->order,
> >               show_gfp_flags(__entry->gfp_flags))
> >  );
> > --
> > 1.8.3.1
>
> --
> Michal Hocko
> SUSE Labs