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Date: Thu, 23 Jun 2016 16:46:14 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Topi Miettinen <toiwoton@gmail.com>
Cc: linux-kernel@vger.kernel.org, luto@kernel.org, serge@hallyn.com,
        keescook@chromium.org, Jonathan Corbet <corbet@lwn.net>,
        Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Serge Hallyn <serge.hallyn@canonical.com>,
        James Morris <james.l.morris@oracle.com>,
        David Howells <dhowells@redhat.com>,
        David Woodhouse <David.Woodhouse@intel.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Petr Mladek <pmladek@suse.com>,
        linux-doc@vger.kernel.org (open list:DOCUMENTATION),
        cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)),
        linux-security-module@vger.kernel.org (open list:CAPABILITIES)
Subject: Re: [PATCH] capabilities: add capability cgroup controller
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On Thu, 23 Jun 2016 18:07:10 +0300 Topi Miettinen <toiwoton@gmail.com> wrote:

> There are many basic ways to control processes, including capabilities,
> cgroups and resource limits. However, there are far fewer ways to find
> out useful values for the limits, except blind trial and error.
> 
> Currently, there is no way to know which capabilities are actually used.
> Even the source code is only implicit, in-depth knowledge of each
> capability must be used when analyzing a program to judge which
> capabilities the program will exercise.
> 
> Add a new cgroup controller for monitoring of capabilities
> in the cgroup.

I'm having trouble understanding how valuable this feature is to our
users, and that's a rather important thing!

Perhaps it would help if you were to explain your motivation:
particular use cases which benefited from this, for example.