panic: kmem_map too small

Robert Watson rwatson at
Thu Oct 26 08:14:56 UTC 2006

On Wed, 25 Oct 2006, Scott Long wrote:

> There are no obvious culprits from what you posted.  The kernel was only 
> trying to allocate 60 bytes, and the 64-byte bucket didn't look to be overly 
> used.  None of the other zones look terribly over-used either. The 'show 
> malloc' command doesn't really give enough stats to be terribly useful, 

What would you add to the output to make it more useful?  The main difference 
between "show malloc" and "vmstat -m", other than any "use over time" 
associated with multiple runs of vmstat -m, is the malloc size bitmask.  This 
is relatively easily added to kern_malloc.c.

> And neither of the commands can effectively track things like contig memory 
> allocator.  Can you try the following two commands:

Want to add "show contigmalloc"?

I've found it significantly easier to debug memory leaks since adding these 
DDB commands, but they are easily enhanced to carry more information than they 
do now.

Robert N M Watson
Computer Laboratory
University of Cambridge

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