linux-kernel - Re: [PATCHv2 11/11] writeback: prevent unnecessary bdi threads wakeups

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Message-ID: <1279897382.9203.95.camel@localhost>
Date:	Fri, 23 Jul 2010 18:03:02 +0300
From:	Artem Bityutskiy <dedekind1@...il.com>
To:	Nick Piggin <npiggin@...e.de>
Cc:	Jens Axboe <axboe@...nel.dk>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 11/11] writeback: prevent unnecessary bdi threads
 wakeups

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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