[cgl_discussion] Re: About Replaceable OOM Killer

[Pavel Machek]

Hi!

> Right, once it is really OOM, you are SOL :-)  Really the only thing you can do at this point in the kernel is to not allocate any more memory, and functions that require more memory just don't work, and the recovery is to reboot..
> 
> IMO, the best answer is to detect a nearly-OOM, or trending-toward-OOM condition before it gets so bad.
> This would allow userland actions, but would require more customization to tune the detection criteria, which would also imply a userland implementation of the monitoring.  We've found that PCP works pretty well for this type of thing.
> See http://oss.sgi.com/projects/pcp/ and http://pcp4cgl.sourceforge.net/.  We did some work with this for CGL 1.0.
> 

Well, I see that as orthogonal.

With right daemon you may prevent OOM in most situations. Kernel still
needs some OOM killer for cases where faileure was just too fast, but
it can now be simpler (and that's good).
								Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]