From: Johannes Weiner <hannes@cmpxchg.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Michal Hocko <mhocko@suse.cz>,
Balbir Singh <bsingharora@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch] mm, memcg: do not allow tasks to be attached with zero limit
Date: Tue, 13 Mar 2012 17:51:18 +0100 [thread overview]
Message-ID: <20120313165117.GA1708@cmpxchg.org> (raw)
In-Reply-To: <20120309105706.4001646a.kamezawa.hiroyu@jp.fujitsu.com>
On Fri, Mar 09, 2012 at 10:57:06AM +0900, KAMEZAWA Hiroyuki wrote:
> On Thu, 8 Mar 2012 17:38:18 -0800
> Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > On Fri, 9 Mar 2012 10:22:55 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> >
> > > On Thu, 8 Mar 2012 12:29:51 -0800
> > > Andrew Morton <akpm@linux-foundation.org> wrote:
> > >
> > > > On Wed, 7 Mar 2012 19:14:49 -0800 (PST)
> > > > David Rientjes <rientjes@google.com> wrote:
> > > >
> > > > > This patch prevents tasks from being attached to a memcg if there is a
> > > > > hard limit of zero.
> > > >
> > > > We're talking about the memcg's limit_in_bytes here, yes?
> > > >
> > > > > Additionally, the hard limit may not be changed to
> > > > > zero if there are tasks attached.
> > > >
> > > > hm, well... why? That would be user error, wouldn't it? What is
> > > > special about limit_in_bytes=0? The memcg will also be unviable if
> > > > limit_in_bytes=1, but we permit that.
> > > >
> > > > IOW, confused.
> > > >
> > > Ah, yes. limit_in_bytes < some small size can cause the same trouble.
> > > Hmm... should we have configurable min_limit_in_bytes as sysctl or root memcg's
> > > attaribute.. ?
> >
> > Why do *anything*? If the operator chose an irrational configuration
> > then things won't work correctly and the operator will then fix the
> > configuration?
> >
>
> Because the result of 'error operaton' is SIGKILL to a task, which may be
> owned by very importang customer of hosting service.
>
> Isn't this severe punishment for error operation ?
>
> Considering again, I have 2 thoughts.
>
> - it should be guarded by MiddleWare, it's not kernel job !
> - memcg should be more easy-to-use, friendly to users.
>
> If the result is just an error as EINVAL or EBUSY, I may not be nervous....
You can still disable the OOM killer. If you don't, you can always
get killed, so I'm not convinced by this patch or a sysctl, either.
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next prev parent reply other threads:[~2012-03-13 16:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-08 3:14 [patch] mm, memcg: do not allow tasks to be attached with zero limit David Rientjes
2012-03-08 6:15 ` KAMEZAWA Hiroyuki
2012-03-08 20:29 ` Andrew Morton
2012-03-09 1:22 ` KAMEZAWA Hiroyuki
2012-03-09 1:38 ` Andrew Morton
2012-03-09 1:57 ` KAMEZAWA Hiroyuki
2012-03-13 16:51 ` Johannes Weiner [this message]
2012-03-14 9:42 ` Michal Hocko
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