Re: [RFC PATCH 1/4] softirq: Limit vector to a single iteration on IRQ tail

Frederic Weisbecker
2018-01-21T16:30:14Z

On Fri, Jan 19, 2018 at 01:47:27PM -0500, David Miller wrote:
> From: Linus Torvalds <torvalds@linux-foundation.org>
> Date: Fri, 19 Jan 2018 10:25:03 -0800
>
> > On Fri, Jan 19, 2018 at 8:16 AM, David Miller <davem@davemloft.net> wrote:
> >>
> >> So this "get requeued" condition I think will trigger always for
> >> networking tunnel decapsulation.
> >
> > Hmm. Interesting and a perhaps bit discouraging.
> >
> > Will it always be just a _single_ level of indirection, or will double
> > tunnels (I assume some people do that, just because the universe is
> > out to get us) then result in this perhaps repeating several times?
>
> Every level of tunnel encapsulation will trigger a new softirq.
>
> So if you have an IP tunnel inside of an IP tunnel that will trigger
> twice.

So we may likely need to come back to a call counter based limit :-s