From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752088AbaILRzZ (ORCPT ); Fri, 12 Sep 2014 13:55:25 -0400 Received: from mail-pd0-f178.google.com ([209.85.192.178]:46730 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092AbaILRzX (ORCPT ); Fri, 12 Sep 2014 13:55:23 -0400 Date: Sat, 13 Sep 2014 02:55:16 +0900 From: Tejun Heo To: Michal Hocko Cc: Vladimir Davydov , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, Li Zefan , "David S. Miller" , Johannes Weiner , Kamezawa Hiroyuki , Glauber Costa , Pavel Emelianov , Andrew Morton , Greg Thelen , Eric Dumazet , "Eric W. Biederman" Subject: Re: [PATCH RFC] memcg: revert kmem.tcp accounting Message-ID: <20140912175516.GB6298@mtj.dyndns.org> References: <1410535618-9601-1-git-send-email-vdavydov@parallels.com> <20140912171809.GA24469@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140912171809.GA24469@dhcp22.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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