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Date: Thu, 10 Jul 2008 11:40:35 -0400
From: Vivek Goyal <vgoyal@redhat.com>
To: Rik van Riel <riel@redhat.com>
Cc: Paul Menage <menage@google.com>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       linux kernel mailing list <linux-kernel@vger.kernel.org>,
       Libcg Devel Mailing List <libcg-devel@lists.sourceforge.net>,
       Balbir Singh <balbir@linux.vnet.ibm.com>,
       Dhaval Giani <dhaval@linux.vnet.ibm.com>,
       Peter Zijlstra <pzijlstr@redhat.com>,
       Kazunaga Ikeno <k-ikeno@ak.jp.nec.com>,
       Morton Andrew Morton <akpm@linux-foundation.org>,
       Thomas Graf <tgraf@redhat.com>, Ulrich Drepper <drepper@redhat.com>
Subject: Re: [RFC] How to handle the rules engine for cgroups
Message-ID: <20080710154035.GA12043@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>
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On Thu, Jul 10, 2008 at 10:48:52AM -0400, Rik van Riel wrote:
> On Thu, 10 Jul 2008 02:23:52 -0700
> "Paul Menage" <menage@google.com> wrote:
> 
> > I don't see the rule-based approach being all that useful for our needs.
> 
> Agreed, there really is no need for a rule-based approach in kernel space.
> 
> There are basically three different cases:
> 
> 1) daemons get started up in their own process groups, this can
>    be handled by the initscripts
> 
> 2) user sessions (ssh, etc) start in their own process groups,
>    this can be handled by PAM
> 
> 3) users fork processes that should go into special process
>    groups - this could be handled by having a small ruleset
>    in userspace handle things, right before calling exec(),

That means application launcher (ex, shell) is aware of the right cgroup
targeted application should go in and then move forked pid to right
cgroup and call exec? Or you had something else in mind?
 
>    it can even be hidden from the application by hooking into
>    the exec() call
> 

This means hooking into libc. So libc will parse rules file, determine
the right cgroup, place application there and then call exec?

CCing, Ulrich also in case he has some thoughts.

Thanks
Vivek