On Fri, 11 Mar 2005, Jean-Michel Caricand wrote:

> I have 4go on my server. Only 800 mo are use. When I launch a uml 
> instance with mem=256M param that work fine. But when launch a uml 
> instance with mem=512M, I get this message : SegFault ....

4go means quatre giga-octets, right?  

As a defense against denial of service, there's a limit of 2^16 memory map 
zones per process.  This interacts badly with UML, for which each 2^12 
bytes is a separate zone, for a max of 2^24 bytes (256 MB).  To raise the 
limit, take the mem= parameter for your largest guest, divide by 2^16 
(65536) and round up by 1 if necessary.  Echo the resulting number (or a 
convenient higher number) into /proc/sys/vm/max_map_count.

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA  90095-1555
Email: [EMAIL PROTECTED]    http://www.math.ucla.edu/~jimc (q.v. for PGP key)


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