Re: BNX Double Buffer Allocation

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Thu, Aug 28, 2008 at 01:24:23PM -0500, David Young wrote:
> On Thu, Aug 28, 2008 at 11:13:12AM -0700, Aaron J. Grier wrote:
> > On Tue, Aug 26, 2008 at 04:03:48PM -0500, David Dudley wrote:
> > > The system compiled with no problem, however when I start the system
> > > with 2 network interfaces connected (bnx0 & bnx1), I get "WARNING:
> > > mclpool limit reached; increase NMBCLUSTERS", and both network
> > > interfaces stop.  I don't get a panic, just the network connections
> > > won't pass data any more.
> > 
> > I have seen this on our NAT at work as well.  bumping NMBCLUSTERS has
> > helped, but what I don't understand is why the network gets completely
> > wedged.  why can't it recover by dropping packets and reclaiming mbufs?
> 
> Drivers for network interfaces reserve many mbufs for receiving packets,
> and they are not smart enough to shrink their reservation.

The mbuf can also be in socket queues; if you drop them you're
effectively killing the connection.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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