Message-ID: <55425332.4050408@ezchip.com>
Date: Thu, 30 Apr 2015 12:07:14 -0400
From: Chris Metcalf <cmetcalf@ezchip.com>
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To: Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>
CC: Frederic Weisbecker <fweisbec@gmail.com>, Don Zickus <dzickus@redhat.com>,
        Ingo Molnar <mingo@kernel.org>, Andrew Jones <drjones@redhat.com>,
        chai wen <chaiw.fnst@cn.fujitsu.com>,
        Ulrich Obergfell <uobergfe@redhat.com>,
        Fabian Frederick <fabf@skynet.be>, Aaron Tomlin <atomlin@redhat.com>,
        Ben Zhang <benzh@chromium.org>, Christoph Lameter <cl@linux.com>,
        Gilad Ben-Yossef <gilad@benyossef.com>,
        Steven Rostedt <rostedt@goodmis.org>, <linux-kernel@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v9 1/3] smpboot: allow excluding cpus from the smpboot
 threads
References: <20150416152808.GA16270@lerouge>	<1429295838-6328-1-git-send-email-cmetcalf@ezchip.com> <20150429152613.1c93dc1387eb4b7af4faa954@linux-foundation.org>
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On 04/29/2015 06:26 PM, Andrew Morton wrote:
> On Fri, 17 Apr 2015 14:37:16 -0400 Chris Metcalf <cmetcalf@ezchip.com> wrote:
>
>> This change allows some cores to be excluded from running the
>> smp_hotplug_thread tasks.  The following commit to update
>> kernel/watchdog.c to use this functionality is the motivating
>> example, and more information on the motivation is provided there.
>>
>> A new smp_hotplug_thread field is introduced, "cpumask", which
>> is cpumask field managed by the smpboot subsystem that indicates whether
>> or not the given smp_hotplug_thread should run on that core; the
>> cpumask is checked when deciding whether to unpark the thread.
>>
>> To limit the cpumask to less than cpu_possible, you must call
>> smpboot_update_cpumask_percpu_thread() after registering.
> Has Thomas commented on any version of this?   t'would be nice.

He offered some specific feedback here:

   https://lkml.org/lkml/2015/4/8/684

that I reflected in the subsequent iteration of the patch series.

Thomas, any additional feedback would be appreciated.

-- 
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com

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