Re: kern/40462: bnx0: Double mbuf allocation failure!

["Michael L. Hitch" <mhitch%lightning.msu.montana.edu@localhost>]

On Fri, 23 Jan 2009, jarle%uninett.no@localhost wrote:

> > Description:
> The system is an IBM e-series rack server with two built-in ethernet
> ports.  The ports are driven by the bnx driver.  It had been running for
> some time using only one network port, and I was trying to bring up the
> second port when it paniced.  I gathered some console log output, and tried
> again.  Same panic.
..
> > How-To-Repeat:
> Bring up two bnx interface on a system?
>
> > Fix:

  I think this occurs because each bnx device attempts to allocate a large
number of receive buffers from the mbuf cluster pool.  The default size
is too small for two bnx devices, and the bnx driver appears to be the 
only one I've seen that panics when it can't allocate the receive buffers.

  You can override this with the NMBCLUSTERS kernel config option (which
required rebuilding the kernel).  Also, enabling the GATEWAY option will
usually double the default NMBCLUSTERS (but also requires a kernel 
rebuild).

  I think in the past I've been able to patch the nmbclusters value in
the kernel using gdb.

  I also seem to recall some comments or discussion about increasing the 
default NMBCLUSTERS, but I don't think anything ever came of that.

--
Michael L. Hitch                        mhitch%montana.edu@localhost
Computer Consultant
Information Technology Center
Montana State University        Bozeman, MT     USA