Subject: Re: [RFC PATCH net-next 0/3] TC: Introduce qevents

From: Petr Machata <[email-masked]>
Date: Wed, 27 May 2020 18:25:10 +0200

Vladimir Oltean <[email-masked]> writes:

> I only took a cursory glance at your patches. Can these "qevents" be
> added to code outside of the packet scheduler, like to the bridge, for
> example? Or can the bridge mark the packets somehow, and then any
> generic qdisc be able to recognize this mark without specific code?
> A very common use case which is currently not possible to implement is
> to rate-limit flooded (broadcast, unknown unicast, unknown multicast)
> traffic. Can your "qevents" be used to describe this, or must it be
> described separately?

You mean something like a "flood" qevent? In principle nothing prevents
this, but it does not strike me as a very good fit. These events are
meant to be used on qdiscs, hence the "q" in the name. I am not sure it
makes sense to reuse them for bridge traffic policing.

Peeking in 802.1Q, I see "Managed objects for per-stream filtering and
policing". If that's related, it seems like it would be conservative to
model the policing directly in the bridge, instead of this round-about
through TC.