Subject: panic: kmem malloc: mb_map too small
To: None <,>
From: Gordon W. Ross <>
List: tech-kern
Date: 10/23/1995 12:05:22
> From: Jason Thorpe <>
> Date: Sat, 21 Oct 1995 17:08:08 -0700

> > panic: kmem_malloc: mb_map too small

> This can happen if your system is dealing with alot of network traffic.  

> As computer networks get larger, and applications grow increasingly 
> network-oriented, I would tend to favor the default NMBCLUSTERS being 
> raised from 256/512 to 1024/2048 (without/with GATEWAY).  Just like we 
> recently raised CHILD_MAX frm 40 to 80, the lower value just doesn't seem 
> to make sense for modern systems anymore...
> Comments?

We can make the problem less likely to occur by increasing NMBCLUSTERS.
However, I think a better solution would be to make the network code
drop packets when it can not allocate more mbufs (not panic).

Perhaps this would require a priority scheme for mbuf allocations,
so you can drop the right ones (usually just Ethernet input).

Gordon Ross