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Date: Wed, 18 Nov 2009 19:40:53 +0000
From: Matthew Garrett <mjg@redhat.com>
To: Kay Sievers <kay.sievers@vrfy.org>
Cc: David Zeuthen <david@fubar.dk>, linux-kernel@vger.kernel.org,
       axboe@kernel.dk, linux-hotplug@vger.kernel.org
Subject: Re: [PATCH] [RFC] Add support for uevents on block device idle
	changes
Message-ID: <20091118194053.GB12944@srcf.ucam.org>
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On Wed, Nov 18, 2009 at 08:30:07PM +0100, Kay Sievers wrote:

> Wouldn't it be good enough, if we add a file "idle_since" which
> contains the time of the actual disk idle time, and userspace can
> schedule a re-examination of that value at the actual end of the idle
> time it is looking for?

That would require either polling or waking up a userspace application 
on every disk access. Doing it in-kernel involves only a single timer 
wakeup for every active/idle transition.

-- 
Matthew Garrett | mjg59@srcf.ucam.org
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