Re: [PATCH v2]oom-kill: CAP_SYS_RESOURCE should get bonus

[David Rientjes]

On Tue, 9 Nov 2010, Alan Cox wrote:

> The reverse can be argued equally - that they can unprotect themselves if
> necessary. In fact it seems to be a "point of view" sort of question
> which way you deal with CAP_SYS_RESOURCE, and that to me argues that
> changing from old expected behaviour to a new behaviour is a regression.
> 

I didn't check earlier, but CAP_SYS_RESOURCE hasn't had a place in the oom 
killer's heuristic in over five years, so what regression are we referring 
to in this thread?  These tasks already have full control over 
oom_score_adj to modify its oom killing priority in either direction.

And, as I said, giving these threads a bonus to be less preferred doesn't 
seem appropriate since (1) it's not a defined or expected behavior of 
CAP_SYS_RESOURCE like it is for sysadmin tasks, and (2) these threads are 
not bound by resource limits and thus have a higher liklihood of consuming 
larger amounts of memory.

That's why I nack'd the patch in the first place and still do, there's no 
regression here and it's not in the best interest of freeing a large 
amount of memory which is the sole purpose of the oom killer.

Futhermore, the heuristic was entirely rewritten, but I wouldn't consider 
all the old factors such as cputime and nice level being removed as 
"regressions" since the aim was to make it more predictable and more 
likely to kill a large consumer of memory such that we don't have to kill 
more tasks in the near future.
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