Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755689AbYGNPkE (ORCPT ); Mon, 14 Jul 2008 11:40:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753900AbYGNPjz (ORCPT ); Mon, 14 Jul 2008 11:39:55 -0400 Received: from mx1.redhat.com ([66.187.233.31]:34623 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753510AbYGNPjy (ORCPT ); Mon, 14 Jul 2008 11:39:54 -0400 Date: Mon, 14 Jul 2008 11:21:42 -0400 From: Vivek Goyal To: David Collier-Brown Cc: KAMEZAWA Hiroyuki , Rik van Riel , Paul Menage , linux kernel mailing list , Libcg Devel Mailing List , Balbir Singh , Dhaval Giani , Peter Zijlstra , Kazunaga Ikeno , Morton Andrew Morton , Thomas Graf , Ulrich Drepper Subject: Re: [RFC] How to handle the rules engine for cgroups Message-ID: <20080714152142.GJ16673@redhat.com> References: <20080701191126.GA17376@redhat.com> <20080703101957.b3856904.kamezawa.hiroyu@jp.fujitsu.com> <20080703155446.GB9275@redhat.com> <6599ad830807100223m2453963cwcfbe6eb1ad54d517@mail.gmail.com> <20080710104852.797fe79c@cuia.bos.redhat.com> <20080710154035.GA12043@redhat.com> <20080711095501.cefff6df.kamezawa.hiroyu@jp.fujitsu.com> <20080714135719.GE16673@redhat.com> <487B665B.9080205@sun.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <487B665B.9080205@sun.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3334 Lines: 81 On Mon, Jul 14, 2008 at 10:44:43AM -0400, David Collier-Brown wrote: > Vivek Goyal wrote: >> If admin has decided to group applications and has written the rules for >> it then applications should not know anything about grouping. So I think >> application writing an script for being placed into the right group should >> be out of question. Now how does an admin write a wrapper around existing >> application without breaking anything else. > > In the Solaris world, processes are placed into cgroups (projects) by > one of two mechanisms: > > 1) inheritance, with everything I create in my existing project. > To get this started, there is a mechanism under login/getty/whatever > reading the /etc/projects file and, for example, tossing user davecb > into a "user.davecb" project. > Placing the login sessions in right cgroup based on uid/gid rules is probably easy as check needs to be placed only on system entry upon login (Pam plugin should do). And after that any job started by the user will automatically start in the same cgroup. > 2) explicit placement with newtask, which starts a program or moves > a process into a project/cgroup > explicit placement of task based on application type will be tricky. > I have a "bg" project which I use for limiting resource consumption of > background jobs, and a background command which either starts or moves > jobs, thusly: > > case "$1" in > [0-9]*) # It's a pid > newtask -p bg -c $1 Ok, this is moving of tasks from one cgroup to other based on pid. This is really easy to do through cgroup file system. Just a matter of writing to task file. > ;; > *) # It's a command-line > newtask -p bg "$@" & > ;; So here a user explicitly invokes the wrapper passing it the targeted cgroup and the application to be launched in that cgroup. This should work if there is a facility if user has created its own cgroups (lets say under user controlled cgroup dir in the hierarchy) and user explicitly wants to control the resources of applications under its dir. For example, /mnt/cgroup | | gid1 gid2 | | | | uid1 uid2 uid3 uid4 | | proj1 proj2 Here probably admin can write the rules for how users are allocated the resources and give ability to users to create subdirs under their cgroups where users can create more cgroups and can do their own resource management based on application tasks and place applications in the right cgroup by writing wrappers as mentioned by you "newtask". But here there is no discrimination of application type by admin. Admin controls resource divisions only based on uid/gid. And users can manage applications within their user groups. In fact I am having hard time thinking in what kind of scenarios, there is a need for an admin to control resource based on application type? Do we really need setups like, on a system databases should get network bandwidth of 30%. If yes, then it becomes tricky where admin need to write a wrapper to place the task in right cgroup without application/user knowing it. Thanks Vivek -- 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/