Re: additional oom-killer tuneable worth submitting?

["Chris Friesen" <cfriesen@nortel.com>]

Alan wrote:

>>The "oom-thresh" value maps to the max expected memory consumption for 
>>that process.  As long as a process uses less memory than the specified 
>>threshold, then it is immune to the oom-killer.

> You've just introduced a deadlock. What happens if nobody is over that
> predicted memory and the kernel uses more resource ?

Based on the discussion with Jesper, we fall back to regular behaviour. 
  (Or possibly hang or reboot, if we added another switch).

>>On an embedded platform this allows the designer to engineer the system 
>>and protect critical apps based on their expected memory consumption. 
>>If one of those apps goes crazy and starts chewing additional memory 
>>then it becomes vulnerable to the oom killer while the other apps remain 
>>protected.

> That is why we have no-overcommit support. Now there is an argument for
> a meaningful rlimit-as to go with it, and together I think they do what
> you really need.

No overcommit only protects the system as a whole, not any particular 
processes.  The purpose of this is to protect specific daemons from 
being killed when the system as a whole is short on memory.  Same 
rationale as for oomadj, but different knob to twiddle.

Chris