erroneous message from locked-up machine

Terry Lambert tlambert2 at
Tue Nov 11 04:08:05 PST 2003

Alex Wilkinson wrote:
> Can someone please elaborate on the acronym KVA ?
> $ sysctl -d kern.ipc.maxpipekva
> kern.ipc.maxpipekva: Pipe KVA limit
> This doesn't tell me enough.

Kernel Virtual Address

The fast pipe code in FreeBSD usesX-Mozilla-Status: 0009the
processes participating in the pipe endpoints, so it uses a
set of wired memory to do its job.  By definition, this means
that it takes a chunk of KVA space in order to get the wired

This tunable value is an administrative limit on the amount
of KVA that can be used up by pipes.  In general, you should
never feel this, unless you are doing strange things with your
pipes.  Massively parallel compiles using pipes to communicate
between the compiler stages, for example.

-- Terry

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