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	<20130324081701.GA13328@gmail.com>
Date: Sun, 24 Mar 2013 15:46:40 +0100
Message-ID: <CAFTL4hx4FLaRR6i9ap9UrCZY4ikhVtLfUqWSsjTpsO3dvShUjQ@mail.gmail.com>
Subject: Re: [GIT PULL] nohz: Full dynticks base interface
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Chris Metcalf <cmetcalf@tilera.com>, Christoph Lameter <cl@linux.com>,
        Geoff Levand <geoff@infradead.org>,
        Gilad Ben Yossef <gilad@benyossef.com>,
        Hakan Akkan <hakanakkan@gmail.com>, Kevin Hilman <khilman@linaro.org>,
        Li Zhong <zhong@linux.vnet.ibm.com>,
        Namhyung Kim <namhyung.kim@lge.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>
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2013/3/24 Ingo Molnar <mingo@kernel.org>:
>
> * Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
>> Hi Ingo,
>>
>> This settles the initial ground to start a special full dynticks tree in -tip
>> that we can iterate incrementally to accelerate the development.
>> It is based on tip:sched/core.
>>
>> I tried to rearrange a bit the naming. We are probably not yet done with
>> that but I guess we can fix it along with the rest.
>>
>> Please pull from:
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
>>       full-dynticks-for-mingo
>>
>> Changes on these commits since they were part of 3.9-rc1-nohz1:
>>
>> * Force a timekeeping CPU over the full dynticks range
>> * Rename CONFIG_NO_HZ_FULL to CONFIG_NO_HZ_EXTENDED
>> * Following *_nohz_extended_* APIs renames
>> * Handle CPU hotplug for timekeeping
>> * Rename full_nohz= kernel parameter to nohz_extended=
>
> Note that boot parameters suck for pretty much any purpose but quirks -
> please also add a (default off!) Kconfig option to easily enable
> nohz_extended for all CPUs.
>
> That way I will be able to test it automatically via randconfig and such.

Sure, I'm adding such an option.

>
> My next question/request after that would be: could we make sure that
> enabling this option does not break any applications or kernel
> functionality, ASAP? Once that is offered, it becomes pushable to v3.10 I
> think.

So that's already the case. I'm careful that, as we iterate, the
changes aren't supposed to break something in the middle. the final
code that eventually shuts the tick down should be the last one in the
series: once we know it is safe to do so.

>
> Meanwhile I have pulled your tree into tip:sched/nohz to stage and test
> it, in the hope that it becomes mergable quickly! :-)

Thanks! :)
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