From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752774AbbDBQEo (ORCPT <rfc822;w@1wt.eu>);
	Thu, 2 Apr 2015 12:04:44 -0400
Received: from mail-wg0-f53.google.com ([74.125.82.53]:33148 "EHLO
	mail-wg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751260AbbDBQEk (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 2 Apr 2015 12:04:40 -0400
Date: Thu, 2 Apr 2015 18:04:35 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>, Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Kevin Hilman <khilman@linaro.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>,
        Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 2/3] clockevents: Restart clockevent device before using
 it again
Message-ID: <20150402160435.GA8045@gmail.com>
References: <cover.1427475606.git.viresh.kumar@linaro.org>
 <a8bce41503c36f6de6be94b0f8854ab646f6745d.1427475606.git.viresh.kumar@linaro.org>
 <20150402133403.GY23123@twins.programming.kicks-ass.net>
 <CAKohpok=HEL4H22-OggBqokgdJvMcK2kBeccpfFk9+aacRX2Mw@mail.gmail.com>
 <20150402150649.GD23123@twins.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20150402150649.GD23123@twins.programming.kicks-ass.net>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Apr 02, 2015 at 07:20:50PM +0530, Viresh Kumar wrote:
> > > Or am I completely missing something?
> > 
> > So yes, if we would have done that in tick_program_event(), it would have
> > been a single place for doing this change..
> > 
> > But, when Thomas ranted [1] at me on this earlier, he said:
> > 
> > "
> > No, we are not doing a state change behind the scene and a magic
> > restore.
> > 
> > 2B) Implement the ONESHOT_STOPPED logic and make sure all of the core
> >     code is aware of it.
> > "
> > 
> 
> lkml.org didn't work for me, alternative link:
> 
> http://marc.info/?l=linux-kernel&m=139966616803683&w=2
> 
> So I've read that (several times) and I thing Thomas meant something
> else.
> 
> So I think he disliked what you did to the clockevent layer, not so much
> you touching tick_program_event(). But the last_state thing (which was
> broken), and you imposing the SHUTDOWN policy for everybody.
> 
> But with the optional ONESHOT_STOPPED state both those are gone, and
> we'd end up with the much simpler patch below.
> 
> Further note that tick-oneshot is the natural place to do this, that is
> the glue layer between the (oneshot) clockevents stuff and the timer
> stuff. Pulling clockevents into hrtimers feels wrong.
> 
> Ingo, do you agree with that after reading Thomas' email?

Yeah, I suppose ...

Thanks,

	Ingo