Re: [patch -mm 08/18] oom: badness heuristic rewrite

From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: David Rientjes <rientjes@google.com>
Cc: kosaki.motohiro@jp.fujitsu.com, Nick Piggin <npiggin@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Rik van Riel <riel@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Balbir Singh <balbir@linux.vnet.ibm.com>,
	linux-mm@kvack.org
Subject: Re: [patch -mm 08/18] oom: badness heuristic rewrite
Date: Wed,  2 Jun 2010 22:54:02 +0900 (JST)	[thread overview]
Message-ID: <20100602222347.F527.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1006011144340.32024@chino.kir.corp.google.com>

> > Such that you can look at your test case or workload and see that
> > it is really improved?
> > 
> 
> I'm glad you asked that because some recent conversation has been 
> slightly confusing to me about how this affects the desktop; this rewrite 
> significantly improves the oom killer's response for desktop users.  The 
> core ideas were developed in the thread from this mailing list back in 
> February called "Improving OOM killer" at 
> http://marc.info/?t=126506191200004&r=4&w=2 -- users constantly report 
> that vital system tasks such as kdeinit are killed whenever a memory 
> hogging task is forked either intentionally or unintentionally.  I argued 
> for a while that KDE should be taking proper precautions by adjusting its 
> own oom_adj score and that of its forked children as it's an inherited 
> value, but I was eventually convinced that an overall improvement to the 
> heuristic must be made to kill a task that was known to free a large 
> amount of memory that is resident in RAM and that we have a consistent way 
> of defining oom priorities when a task is run uncontained and when it is a 
> member of a memcg or cpuset (or even mempolicy now), even in the case when 
> it's contained out from under the task's knowledge.  When faced with 
> memory pressure from an out of control or memory hogging task on the 
> desktop, the oom killer now kills it instead of a vital task such as an X 
> server (and oracle, webserver, etc on server platforms) because of the use 
> of the task's rss instead of total_vm statistic.

The above story teach us oom-killer need some improvement. but it haven't
prove your patches are correct solution. that's why you got to ask testing way.

Nobody have objection to fix KDE OOM issue.

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