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Date: Thu, 15 May 2014 00:50:11 -0400
From: Tejun Heo <tj@kernel.org>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Vojtech Pavlik <vojtech@suse.cz>, Jiri Slaby <jslaby@suse.cz>,
        Jiri Kosina <jkosina@suse.cz>, linux-kernel@vger.kernel.org,
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        Frederic Weisbecker <fweisbec@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>, Dipankar Sarma <dipankar@in.ibm.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [RFC 09/16] kgr: mark task_safe in some kthreads
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Hello, Mike.

On Thu, May 15, 2014 at 06:46:18AM +0200, Mike Galbraith wrote:
> > I think it'd be healthier to identify the use cases and then provide
> > proper interface for it.  Note that workqueue can now expose interface
> > to modify concurrency, priority and cpumask to userland which
> > writeback workers are already using.
> 
> You can't identify a specific thing, any/all of it can land on the
> user's diner plate, so he should be able to make the decisions.  Power
> to the user and all that, if he does something stupid, tuff titty.  User
> getting to call the shots, and getting to keep the pieces when he fscks
> it all up is wonderful stuff, lets kernel people off the hook :)

Do we know specific kthreads which need to be exposed with this way?
If there are good enough reasons for specific ones, sure, but I don't
think "we can't change any of the kthreads because someone might be
diddling with it" is something we can sustain in the long term.

Thanks.

-- 
tejun