[ECOS] MBUF leak

[Andrew Lunn <andrew dot lunn at ascom dot ch>]

Re: the mbuf/cluster leak message...

If you look at the trace, you see that both the number of mbufs and
the number of clusters slowly decreases. You happen to run out of
clusters first, but thats because there are less of them. Your real
problem is an mbuf leak. An mbuf is used to hold part of a packet. If
it has to hold more than about 100 bytes, a cluster is attached to the
mbuf, which can hold up to 2K bytes. If you loose an mbuf, you also
loose the cluster thats attached.

My experience is that the basic IP stack is OK. Leaks happen in either
the ethernet device driver or the eth_drv.c layer. Thats where i would
start looking. Try to use a UDP test program. Fire UDP packets at the
target and see if it leaks. If so its the receive path that has the
problem. If not, try sending UDP packets from the target. If that
leaks you know its the TX path that has a problem. Again from
experience problems happen during some sort of overload
condition. Check what happens when the RX or TX ring buffer overflows
in the device driver etc.

   Andrew