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From: <leonid.moiseichuk@nokia.com>
To: <kosaki.motohiro@gmail.com>
CC: <anton.vorontsov@linaro.org>, <penberg@kernel.org>,
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Subject: RE: [PATCH 2/5] vmevent: Convert from deferred timer to deferred
 work
Thread-Topic: [PATCH 2/5] vmevent: Convert from deferred timer to deferred
 work
Thread-Index: AQHNP/HM8KMmZkc4xkKq2ZDXaeCP2Zbvq0sAgAA7gACAACLOoP//4JWAgAAi/oD//+B6AIAAIckQ///hF4AABKRTEA==
Date: Fri, 8 Jun 2012 07:49:06 +0000
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> -----Original Message-----
> From: ext KOSAKI Motohiro [mailto:kosaki.motohiro@gmail.com]
> Sent: 08 June, 2012 10:33
> To: Moiseichuk Leonid (Nokia-MP/Espoo)
.. 
> Wrong. CPU don't realized the running code belong to userspace or kernel.
> Every code just consume a power. That's why polling timer is wrong from
> point of power consumption view.
???
We are talking about different things.
User-space code could be dropped, distributed between several applications and has not deferred timers support.
For polling API the user-space code has to be executed quite often.
Localizing this code in kernel additionally allows to avoid vmsat/meminfo generation and parsing overhead as well.