From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
cgroups@vger.kernel.org, Li Zefan <lizefan@huawei.com>,
"David S. Miller" <davem@davemloft.net>,
Johannes Weiner <hannes@cmpxchg.org>,
Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Glauber Costa <glommer@gmail.com>,
Pavel Emelianov <xemul@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Thelen <gthelen@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH RFC] memcg: revert kmem.tcp accounting
Date: Sat, 13 Sep 2014 02:55:16 +0900 [thread overview]
Message-ID: <20140912175516.GB6298@mtj.dyndns.org> (raw)
In-Reply-To: <20140912171809.GA24469@dhcp22.suse.cz>
Hello, guys.
On Fri, Sep 12, 2014 at 07:18:09PM +0200, Michal Hocko wrote:
> On Fri 12-09-14 19:26:58, Vladimir Davydov wrote:
> > memory.kmem.tcp.limit_in_bytes works as the system-wide tcp_mem sysctl,
> > but per memory cgroup. While the existence of the latter is justified
> > (it prevents the system from becoming unusable due to uncontrolled tcp
> > buffers growth) the reason why we need such a knob in containers isn't
> > clear to me.
>
> Parallels was the primary driver for this change. I haven't heard of
> anybody using the feature other than Parallels. I also remember there
> was a strong push for this feature before it was merged besides there
> were some complains at the time. I do not remember details (and I am
> one half way gone for the weekend now) so I do not have pointers to
> discussions.
>
> I would love to get rid of the code and I am pretty sure that networking
> people would love this go even more. I didn't plan to provide kmem.tcp.*
> knobs for the cgroups v2 interface but getting rid of it altogether
> sounds even better. I am just not sure whether some additional users
> grown over time.
> Nevertheless I am really curious. What has changed that Parallels is not
> interested in kmem.tcp anymore?
So, I'd love to see this happen too but I don't think we can do this.
People use published interface. The usages might be utterly one-off
and mental but let's please not underestimate the sometimes senseless
creativity found in the wild. We simply can't remove a bunch of
control knobs like this.
Thanks.
--
tejun
next prev parent reply other threads:[~2014-09-12 17:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-12 15:26 [PATCH RFC] memcg: revert kmem.tcp accounting Vladimir Davydov
2014-09-12 17:18 ` Michal Hocko
2014-09-12 17:55 ` Tejun Heo [this message]
2014-09-12 21:43 ` Andrew Morton
2014-09-16 6:16 ` Tejun Heo
2014-09-15 7:42 ` Vladimir Davydov
2014-09-16 6:14 ` Tejun Heo
2014-09-16 8:38 ` Vladimir Davydov
2014-09-15 7:36 ` Vladimir Davydov
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