Re: route cache DoS testing and softirqs

[kuznet]

Hello!

> > We had one full solution for this issue not changing anything
> > in scheduler/softirq relationship: to run rcu task for the things
> > sort of dst cache not from process context, but essentially as part
> > of do_softirq(). Simple, stupid and apparently solves new problems
> > which rcu created.
> 
> Can you be a little bit more specific about this solution ?

It is about that your suggestion, which you outlined below :-)

> as indicated by my earlier experiments. We have potential fixes
> for RCU through a call_rcu_bh() interface where completion of a
> softirq handler is a quiescent state. I am working on forward porting
> that old patch from our discussion last year and testing in my
> environment. That should increase the number of quiescent state
> points significantly and hopefully reduce the grace period significantly.
> But this does nothing to help userland starvation.

Alexey
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/