From mboxrd@z Thu Jan  1 00:00:00 1970
From: Artem Bityutskiy <dedekind1@gmail.com>
Subject: Re: [PATCHv5 12/15] writeback: optimize periodic bdi thread wakeups
Date: Sun, 25 Jul 2010 13:41:09 +0300
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	 <1280046581-23623-13-git-send-email-dedekind1@gmail.com>
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Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
To: Jens Axboe <axboe@kernel.dk>
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On Sun, 2010-07-25 at 11:29 +0300, Artem Bityutskiy wrote:
> +static void wakeup_timer_fn(unsigned long data)
> +{
> +	struct backing_dev_info *bdi =3D (struct backing_dev_info *)data;
> +
> +	spin_lock(&bdi->wb_lock);
> +	if (bdi->wb.task) {
> +		wake_up_process(bdi->wb.task);
> +	} else {
> +		/*
> +		 * When bdi tasks are inactive for long time, they are killed.
> +		 * In this case we have to wake-up the forker thread which
> +		 * should create and run the bdi thread.
> +		 */
> +		wake_up_process(default_backing_dev_info.wb.task);
> +	}
> +	spin_unlock(&bdi->wb_lock);
> +}

OK, since now we use this lock in a timer, this should become a
spin_lock_bh().

--=20
Best Regards,
Artem Bityutskiy (=D0=90=D1=80=D1=82=D1=91=D0=BC =D0=91=D0=B8=D1=82=D1=8E=
=D1=86=D0=BA=D0=B8=D0=B9)