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Date: Wed, 9 May 2012 17:26:46 +0300
Message-ID: <CAOtvUMcrymsv3_sN8mTmAmf1fbJYNq-k4wD4i_wBMuojGiRLRQ@mail.gmail.com>
Subject: Re: [PATCH v1 3/6] workqueue: introduce schedule_on_each_cpu_cond
From: Gilad Ben-Yossef <gilad@benyossef.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        John Stultz <johnstul@us.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Mel Gorman <mel@csn.ul.ie>, Mike Frysinger <vapier@gentoo.org>,
        David Rientjes <rientjes@google.com>, Hugh Dickins <hughd@google.com>,
        Minchan Kim <minchan.kim@gmail.com>,
        Konstantin Khlebnikov <khlebnikov@openvz.org>,
        Christoph Lameter <cl@linux.com>, Chris Metcalf <cmetcalf@tilera.com>,
        Hakan Akkan <hakanakkan@gmail.com>,
        Max Krasnyansky <maxk@qualcomm.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, linux-mm@kvack.org
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On Mon, May 7, 2012 at 8:17 PM, Tejun Heo <tj@kernel.org> wrote:
> Hello,
>
> On Sun, May 06, 2012 at 04:15:30PM +0300, Gilad Ben-Yossef wrote:
>> A single helper function called schedule_on_each_cpu_cond() is very
>> obvious to find to someone reading the source or documentation. On
>> the other hand figuring out that the helper functions that handle
>> cpu hotplug and cpumask allocation are there for that purpose is a
>> bit more involved.
>>
>> That was my thinking at least.
>
> Yeah, having common mechanism is nice, but I just prefer iterators /
> helpers which can be embedded in the caller to interface which takes a
> callback unless the execution context is actually asynchronous to the
> caller. ?We don't use nested functions / scopes in kernel which makes
> those callbacks (higher order functions, lambdas, gammas, zetas
> whatever) painful to use and follow.
>
>> The way i see it, I can either obliterate on_each_cpu_cond() and out
>> its code in place in the LRU path, or fix the callback to get an
>> extra private data parameter -
>
> Unless we can code up something pretty, I vote for just open coding it
> for now. ?If we grow more usages like this, maybe we'll be able to see
> the pattern better and come up with better abstraction.

Got you. Will do.

Thanks.
Gilad


> --
> tejun


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Gilad Ben-Yossef
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