[Bridge] [PATCH net-next] net: bridge: add STP xstats

[Vivien Didelot]

On Tue, 10 Dec 2019 22:15:26 +0200, Nikolay Aleksandrov <nikolay at cumulusnetworks.com> wrote:
> >>>> Why do you need percpu ? All of these seem to be incremented with the
> >>>> bridge lock held. A few more comments below.
> >>>
> >>> All other xstats are incremented percpu, I simply followed the pattern.
> >>>
> >>
> >> We have already a lock, we can use it and avoid the whole per-cpu memory handling.
> >> It seems to be acquired in all cases where these counters need to be changed.
> > 
> > Since the other xstats counters are currently implemented this way, I prefer
> > to keep the code as is, until we eventually change them all if percpu is in
> > fact not needed anymore.
> > 
> > The new series is ready and I can submit it now if there's no objection.
> 
> There is a reason other counters use per-cpu - they're incremented without any locking from fast-path.
> The bridge STP code already has a lock which is acquired in all of these paths and we don't need
> this overhead and the per-cpu memory allocations. Unless you can find a STP codepath which actually
> needs per-cpu, I'd prefer you drop it.

Ho ok I understand what you mean now. I'll drop the percpu attribute.


Thanks,

	Vivien