Re: [patch -mm 1/2] oom: badness heuristic rewrite

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Mon, 2 Aug 2010 18:52:40 -0700 (PDT)
David Rientjes <rientjes@google.com> wrote:

> On Tue, 3 Aug 2010, KAMEZAWA Hiroyuki wrote:
> 
> > > Hmm, then, oom_score shows the values for all limitations in array ?
> > > 
> > Anyway, the fact "oom_score can be changed by the context of OOM" may
> > confuse admins. "OMG, why low oom_score application is killed! Shit!"
> > 
> > Please add additional cares for users if we go this way or remove
> > user visible oom_score file from /proc.
> > 
> 
> Sure, a task could be killed with a very low /proc/pid/oom_score, but only 
> if its cpuset is oom, for example, and it has the highest score of all 
> tasks attached to that oom_score.  So /proc/pid/oom_score needs to be 
> considered in the context in which the oom occurs: system-wide, cpuset, 
> mempolicy, or memcg.  That's unchanged from the old oom killer.
> 

unchanged ?

Assume 2 proceses A, B which has oom_score_adj of 300 and 0
And A uses 200M, B uses 1G of memory under 4G system

Under the system. 
	A's socre = (200M *1000)/4G + 300 = 350
	B's score = (1G * 1000)/4G = 250.

In the cpuset, it has 2G of memory.
	A's score = (200M * 1000)/2G + 300 = 400
	B's socre = (1G * 1000)/2G = 500

This priority-inversion don't happen in current system.

I misunderstand ?


Thanks,
-Kame



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