On Mon, Mar 11, 2019 at 4:47 PM Michal Hocko <[email protected]> wrote: > > On Fri 01-03-19 15:38:54, Yafang Shao wrote: > > If we want to know the zone type, we have to check whether > > CONFIG_ZONE_DMA, CONFIG_ZONE_DMA32 and CONFIG_HIGHMEM are set or not, > > that's not so convenient. > > > > We'd better show the zone type directly. > > I do agree that zone number is quite PITA to process in general but do > we really need this information in the first place? Why do we even care? >
Sometimes we want to know this event occurs in which zone, then we can get the information of this zone, for example via /proc/zoneinfo. It could give us more information for debugging. > Zones are an MM internal implementation details and the more we export > to the userspace the more we are going to argue about breaking userspace > when touching them. So I would rather not export that information unless > it is terribly useful. > I 'm not sure whether zone type is terribly useful or not, but the 'zid' is useless at all. I don't agree that Zones are MM internal. We can get the zone type in many ways, for example /proc/zoneinfo. If we show this event occurs in which zone, we'd better show the zone type, or we should drop this 'zid'. > > Signed-off-by: Yafang Shao <[email protected]> > > --- > > include/trace/events/vmscan.h | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h > > index a1cb913..4c8880b 100644 > > --- a/include/trace/events/vmscan.h > > +++ b/include/trace/events/vmscan.h > > @@ -73,7 +73,10 @@ > > __entry->order = order; > > ), > > > > - TP_printk("nid=%d zid=%d order=%d", __entry->nid, __entry->zid, > > __entry->order) > > + TP_printk("nid=%d zid=%-8s order=%d", > > + __entry->nid, > > + __print_symbolic(__entry->zid, ZONE_TYPE), > > + __entry->order) > > ); > > > > TRACE_EVENT(mm_vmscan_wakeup_kswapd, > > @@ -96,9 +99,9 @@ > > __entry->gfp_flags = gfp_flags; > > ), > > > > - TP_printk("nid=%d zid=%d order=%d gfp_flags=%s", > > + TP_printk("nid=%d zid=%-8s order=%d gfp_flags=%s", > > __entry->nid, > > - __entry->zid, > > + __print_symbolic(__entry->zid, ZONE_TYPE), > > __entry->order, > > show_gfp_flags(__entry->gfp_flags)) > > ); > > -- > > 1.8.3.1 > > > > -- > Michal Hocko > SUSE Labs
