4.10-RELEASE and -STABLE crashing regularly under load

[Andrew Kinney]

On 16 Jun 2004 at 0:52, Tamas TEVESZ wrote:

> On Tue, 15 Jun 2004, Andrew Kinney wrote:
> 
>  > There's your problem.  va=0 usually happens when your run out of
>  KVA > and pmap functions choke (trap 12 panic) when they see va=0 or
>  > numbers derived from that variable.  It's not nice, but it's what >
>  happens.  This is the number one problem on systems with 2GB+ of RAM
>  > (you have 4GB, so you'll run into this a lot). > > Try increasing
>  KVA_PAGES in your kernel config and recompiling.  It's > worked in
>  almost every other case like this where large memory > configurations
>  are in use.
> 
> thank you very much. do you perhaps have any suggestions what sould i
> set for it? as far as i can track, depending on whether PAE is in use
> KVA_PAGES will be either 256 or 512. for starters, i don't even know
> whether i'm really using pae (i am, i assume?), and in either case,
> what would be a likely value for KVA_PAGES?
> 

Set it to 512.  Unless something has changed since 4.8 (what we're 
using here), PAE is not enabled by default and you probably wouldn't 
want to use it unless you had more than 4GB of RAM since it does take 
a performance hit from the additional paging algorithms.  KVA_PAGES 
set to 512 gives you a 2GB/2GB user space / kernel space split which 
is necessary for a 4GB machine to run reliably at any decent load.  
You would set it in your kernel config and then rebuild the kernel.  
If you use linux emulation at all, you'll want to rebuild the world 
instead.  How to do this is covered in the documentation at 
freebsd.org.

Sincerely,
Andrew Kinney
President and
Chief Technology Officer
Advantagecom Networks, Inc.
http://www.advantagecom.net