Re: rbuf starvation in the iwn driver

[David Young <dyoung%pobox.com@localhost>]

On Mon, Apr 05, 2010 at 08:38:41AM -0600, Sverre Froyen wrote:
> Monitoring the number-of-free-rbufs counter during network traffic, I find 
> that 
> it normally stays at 32, occasionally dropping into the twenties. Sometimes, 
> however, the count will abruptly jump to zero. At this point, the free count 
> does not recover but remains at zero for a *long* time. The interface does 
> not 
> receive any packets as long as the driver has no free rbufs. After about ten 
> minutes, I see a flurry of calls to iwn_free_rbuf and the free count returns 
> to 
> 32. At this point the interface is working properly again.

During the flurry of calls to iwn_free_rbuf(), can you get a backtrace
in iwn_free_rbuf()?  I hope that will show us what mechanism frees them
in a flurry.

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933