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Message-ID: <5735F4B1.1010704@laposte.net>
Date: Fri, 13 May 2016 17:37:21 +0200
From: Sebastian Frias <sf84@laposte.net>
MIME-Version: 1.0
Subject: Re: [PATCH] mm: add config option to select the initial overcommit
 mode
References: <5731CC6E.3080807@laposte.net>	<20160513080458.GF20141@dhcp22.suse.cz>	<573593EE.6010502@free.fr>	<20160513095230.GI20141@dhcp22.suse.cz>	<5735AA0E.5060605@free.fr>	<20160513114429.GJ20141@dhcp22.suse.cz>	<5735C567.6030202@free.fr>	<20160513140128.GQ20141@dhcp22.suse.cz> <20160513160410.10c6cea6@lxorguk.ukuu.org.uk>
In-Reply-To: <20160513160410.10c6cea6@lxorguk.ukuu.org.uk>
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Sender: owner-linux-mm@kvack.org
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To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>, Michal Hocko <mhocko@kernel.org>
Cc: Mason <slash.tmp@free.fr>, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>

Hi Alan,

On 05/13/2016 05:04 PM, One Thousand Gnomes wrote:
>>> Perhaps Sebastian's choice could be made to depend on CONFIG_EMBEDDED,
>>> rather than CONFIG_EXPERT?  
>>
>> Even if the overcommit behavior is different on those systems the
>> primary question hasn't been answered yet. Why cannot this be done from
>> the userspace? In other words what wouldn't work properly?
> 
> Most allocations in C have no mechanism to report failure.
> 
> Stakc expansion failure is not reportable. Copy on write failure is not
> reportable and so on.

But wouldn't those affect a given process at at time?
Does that means that the OOM-killer is woken up to kill process X when those situations arise on process Y?

Also, under what conditions would copy-on-write fail?

Best regards,

Sebastian

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