Re: [PATCH V2] mac80211: Revise,pending queue depth in ieee80211_local data structure

[Johannes Berg <johannes@sipsolutions.net>]

On Sun, 2010-03-21 at 11:01 +0900, Bruno Randolf wrote:
> On Sunday 21 March 2010 05:40:05 Johannes Berg wrote:
> > On Sat, 2010-03-20 at 21:02 +0100, Lorenzo Bianconi wrote:
> > > >> setup 2 wireless cards, talking to each other (i use IBSS) on
> > > >> different
> > > 
> > > >> machines. then setup routing like this:
> > > PC1<--ethernet cable-->Device1<--wireless link-->Device2<--ethernet
> > > cable-->PC2
> > 
> > I'm not really sure how this scenario differs from injecting traffic
> > locally, but I'll try to reproduce.
> 
> if you generate traffic locally it's enough to stop the queues, this will 
> cause userspace to stop generating traffic. in the forwarding case (which we 
> are talking about) stopping the queues will not stop the sender to send 
> traffic, thus we have to start dropping packets at some point. 

So I tried this scenario, and I see the queues stopping, and traffic
being dropped quite as you'd want it. Even the race condition that I
noticed didn't ever trigger.

Please make sure you're using a kernel recent enough to include the
fixes, maybe try compat-wireless.

johannes