allocating 14KB memory per packet compression/decompression results in vm_fault

Peter Jeremy PeterJeremy at
Fri Nov 4 01:49:09 PST 2005

[dropping -net]
On Thu, 2005-Nov-03 22:56:30 -0800, kamal kc wrote:
>as i said before the compression/decompression works
>fine. but soon the kernel would panic with one 
>of the vm_fault: error message.

What's the exact panic and traceback?  Have you enabled the various

>what would be the best possible way to 
>allocate/deallocate 14KB memory per packet without 
>causing vm_faults ?? 

The most efficient way would be to statically allocate the dictionary
and string tables.  The downside is that you then need to serialise
the [de]compression.

You could look at zone(9) as an alternative to malloc(9).

>is there anything i am missing ??

- Are you correctly allocating the mbuf for the outgoing packet correctly?
- Are you correctly freeing the mbuf for the incoming packet?
- Are you sure that you're not writing outside the bounds of one of the
  memory blocks you're allocating?

Peter Jeremy

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