Subject: Re: [PATCHv2 11/11] writeback: prevent unnecessary bdi threads
 wakeups
From: Artem Bityutskiy <dedekind1@gmail.com>
Reply-To: dedekind1@gmail.com
To: Nick Piggin <npiggin@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
In-Reply-To: <20100722080511.GA9377@amd>
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	 <20100722031922.GA3446@amd> <1279781304.3044.12.camel@localhost>
	 <20100722080511.GA9377@amd>
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Date: Fri, 23 Jul 2010 18:03:02 +0300
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On Thu, 2010-07-22 at 18:05 +1000, Nick Piggin wrote:
> This is producing 2 unrequired context switches, so I really would
> like to see it done properly. Setting up a timer is really pretty
> simple (or if you would care to implement a delayed process wakeup
> API, I think that would be useful -- I'm surprised there isn't one
> already).

It reduces flusher thread wake-up count a lot, BTW. I've just sent v4 of
the patch set which implements this, see patch 12.

Nick, could you please take a look at patch 10 in that v4 series. I've
added memory barriers, they are always tricky, and last time I remember
you helped me to use barriers properly.

Thanks!

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

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