From: Vladimir Davydov <vdavydov@parallels.com>
To: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>, Greg Thelen <gthelen@google.com>,
Hugh Dickins <hughd@google.com>,
Motohiro Kosaki <Motohiro.Kosaki@us.fujitsu.com>,
Glauber Costa <glommer@gmail.com>, Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Pavel Emelianov <xemul@parallels.com>,
Konstantin Khorenko <khorenko@parallels.com>,
LKML-MM <linux-mm@kvack.org>,
LKML-cgroups <cgroups@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] memory cgroup: my thoughts on memsw
Date: Wed, 10 Sep 2014 16:01:57 +0400 [thread overview]
Message-ID: <20140910120157.GA13796@esperanza> (raw)
In-Reply-To: <540DB4EC.6060100@jp.fujitsu.com>
On Mon, Sep 08, 2014 at 10:53:48PM +0900, Kamezawa Hiroyuki wrote:
> (2014/09/08 20:01), Vladimir Davydov wrote:
> >On Sat, Sep 06, 2014 at 08:15:44AM +0900, Kamezawa Hiroyuki wrote:
> >>As you noticed, hitting anon+swap limit just means oom-kill.
> >>My point is that using oom-killer for "server management" just seems crazy.
> >>
> >>Let my clarify things. your proposal was.
> >> 1. soft-limit will be a main feature for server management.
> >> 2. Because of soft-limit, global memory reclaim runs.
> >> 3. Using swap at global memory reclaim can cause poor performance.
> >> 4. So, making use of OOM-Killer for avoiding swap.
> >>
> >>I can't agree "4". I think
> >>
> >> - don't configure swap.
> >
> >Suppose there are two containers, each having soft limit set to 50% of
> >total system RAM. One of the containers eats 90% of the system RAM by
> >allocating anonymous pages. Another starts using file caches and wants
> >more than 10% of RAM to work w/o issuing disk reads. So what should we
> >do then?
> >We won't be able to shrink the first container to its soft
> >limit, because there's no swap. Leaving it as is would be unfair from
> >the second container's point of view. Kill it? But the whole system is
> >going OK, because the working set of the second container is easily
> >shrinkable. Besides there may be some progress in shrinking file caches
> >from the first container.
> >
> >> - use zram
> >
> >In fact this isn't different from the previous proposal (working w/o
> >swap). ZRAM only compresses data while still storing them in RAM so we
> >eventually may get into a situation where almost all RAM is full of
> >compressed anon pages.
> >
>
> In above 2 cases, "vmpressure" works fine.
What if a container allocates memory so fast that the userspace thread
handling its threshold notifications won't have time to react before it
eats all memory?
Thanks,
Vladimir
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next prev parent reply other threads:[~2014-09-10 12:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-04 14:30 [RFC] memory cgroup: my thoughts on memsw Vladimir Davydov
2014-09-04 22:03 ` Kamezawa Hiroyuki
2014-09-05 8:28 ` Vladimir Davydov
2014-09-05 14:20 ` Kamezawa Hiroyuki
2014-09-05 16:00 ` Vladimir Davydov
2014-09-05 23:15 ` Kamezawa Hiroyuki
2014-09-08 11:01 ` Vladimir Davydov
2014-09-08 13:53 ` Kamezawa Hiroyuki
2014-09-09 10:39 ` Vladimir Davydov
2014-09-11 2:04 ` Kamezawa Hiroyuki
2014-09-11 8:23 ` Vladimir Davydov
2014-09-11 8:53 ` Kamezawa Hiroyuki
2014-09-11 9:50 ` Vladimir Davydov
2014-09-10 12:01 ` Vladimir Davydov [this message]
2014-09-11 1:22 ` Kamezawa Hiroyuki
2014-09-11 7:03 ` Vladimir Davydov
2014-09-15 19:14 ` Johannes Weiner
2014-09-16 1:34 ` Kamezawa Hiroyuki
2014-09-17 15:59 ` Vladimir Davydov
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