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Date: Sat, 27 Nov 2010 17:36:54 -0800 (PST)
From: David Rientjes <rientjes@google.com>
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To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Andrew Morton <akpm@osdl.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2]mm/oom-kill: direct hardware access processes should
 get bonus
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On Tue, 23 Nov 2010, KOSAKI Motohiro wrote:

> > > > I think in cases of heuristics like this where we obviously want to give 
> > > > some bonus to CAP_SYS_ADMIN that there is consistency with other bonuses 
> > > > given elsewhere in the kernel.
> > > 
> > > Keep comparision apple to apple. vm_enough_memory() account _virtual_ memory.
> > > oom-killer try to free _physical_ memory. It's unrelated.
> > > 
> > 
> > It's not unrelated, the LSM function gives an arbitrary 3% bonus to 
> > CAP_SYS_ADMIN.  
> 
> Unrelated. LSM _is_ security module. and It only account virtual memory.
> 

I needed a small bias for CAP_SYS_ADMIN tasks so I chose 3% since it's the 
same proportion used elsewhere in the kernel and works nicely since the 
badness score is now a proportion.  If you'd like to propose a different 
percentage or suggest removing the bias for root tasks altogether, feel 
free to propose a patch.  Thanks!