Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750984Ab3F1EJg (ORCPT ); Fri, 28 Jun 2013 00:09:36 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:37981 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769Ab3F1EJe (ORCPT ); Fri, 28 Jun 2013 00:09:34 -0400 Date: Thu, 27 Jun 2013 21:09:30 -0700 From: Tejun Heo To: Mike Galbraith Cc: Tim Hockin , Li Zefan , Containers , Cgroups , bsingharora , "dhaval.giani" , Kay Sievers , jpoimboe , "Daniel P. Berrange" , lpoetter , workman-devel , "linux-kernel@vger.kernel.org" Subject: Re: cgroup: status-quo and userland efforts Message-ID: <20130628040930.GC2500@htj.dyndns.org> References: <20130422214159.GG12543@htj.dyndns.org> <20130625000118.GT1918@mtj.dyndns.org> <20130626212047.GB4536@htj.dyndns.org> <1372311907.5871.78.camel@marge.simpson.net> <20130627180143.GD5599@mtj.dyndns.org> <1372391198.5989.110.camel@marge.simpson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1372391198.5989.110.camel@marge.simpson.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3374 Lines: 73 Hello, Mike. On Fri, Jun 28, 2013 at 05:46:38AM +0200, Mike Galbraith wrote: > Sure, because in private property and I mandatory agent, I see "gimme > yer wallet bitch", an incredibly arrogant and brutal mugging. That's > not the way it's meant, I know that, but that's how it comes across. > You asked, so you get the straight up answer. I don't know. It reads more like tungue-in-cheek thing to me rather than being actually arrogant, and some part of the brutality is necessary at this point. > Offering to manage cgroups is one thing, very generous, forcefully > placing itself between user and kernel quite another. Perhaps I > misread, but my interpretation was that the intent is to make systemd a > mandatory agent, even saw reference to it taking up residence in the > kernel tree (that bit made me chuckle, pull request would have to be > very cleverly worded methinks). I'm sure it will be quite capable, its > authors are. However, when I want to talk to my kernel, I expect to be > able to tell anyone else using the phone to hang up.. now. I don't know how to respond to this. It feels more emotional than technical. > It's useful now, usable to the point that enterprise users exist who > have integrated cgroups into their business model. But then you know > that. Sure, there are problems, things could and no doubt will get a > lot better. No, it's completely messed up. We're now starting to see users trying to embed low level cgroup details into their binaries and cgroup is exposing sysctl-level konbs which are directly tied to internal implementation of core subsystems. cgroup successfully bypassed the usual kernel API policing with the help of hierarchical filesystem interface which allows delegation on the surface. We completely fucked up. This is a full scale disaster unrolling. > However, wrt userspace agent, no agent is going to be the right answer > for all, so that agent needs to have a step aside button so another > agent can be tasked with the managerial duties, whether that be little > ole /me or Aunt Tilly piddling with this and that because we damn well > feel like it, or BigFoot company X going massively wild and crazy doing > their business thing. *ANY* agent is better than now. We need to back the hell out of direct usages as soon as possible. cgroup is leaking kernel implementation details into individual binaries. The current situation is dangerous and putting an agent inbetween is a good way of gradually backing out of it. > No, it's not at all crazy, _offering_ the user a managerial service is > great, generous, way to go guys, pass out the white hats. Use force, > and those pretty white hats turn black as night, hero to villain. No, it's completely crazy. Full psycho crazy. You just don't realize it yet. > systemd and no systemd is also a valid issue. I'm sure it'll all get > worked out, but that link, and others like it make me see bright red. That red is nothing compared to the kernel implementation detail leak going on right now. The alarm for that has been blinking psychedelically for some time now. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/