Subject: Re: 7GB memtest causes hard system hang.
To: Greg Oster <>
From: Frank van der Linden <>
List: port-amd64
Date: 01/16/2006 22:22:24
On Mon, Jan 16, 2006 at 11:33:08AM -0600, Greg Oster wrote:
> (Without the "options NKMEMPAGES=150000" tweak, the machine is basically
> useless to me -- I can easily run "too much stuff" that gets me to the 
> "no pv entries available" panic :( )
> The proper fix is to fix the pmap code.  A short-term workaround is to 
> do the NKMEMPAGES bump above...

The pmap code isn't really the problem here. Running out of kernel
memory (kmem_map in this case) is hard to recover from. With the current
setup, all that we can do is set nkmempages to a better default value.

Currently, the default maximum for amd64 is still 128M, which is way
too low for machines with > 4G of memory. 1G is probably a better
value for those. Tuning these parameters is somewhat of a black art.

- Frank