From mboxrd@z Thu Jan  1 00:00:00 1970
From: Artem Bityutskiy <dedekind1@gmail.com>
Subject: Re: [RFC][PATCH 14/16] writeback: move bdi threads exiting logic
 to the forker thread
Date: Tue, 20 Jul 2010 15:23:19 +0300
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Cc: Jens Axboe <axboe@kernel.dk>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Christoph Hellwig <hch@infradead.org>
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In-Reply-To: <20100718070231.GK23811@infradead.org>
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List-Id: linux-fsdevel.vger.kernel.org

On Sun, 2010-07-18 at 03:02 -0400, Christoph Hellwig wrote:
> > +	if (wakeup_default) {
> >  		trace_writeback_nothread(bdi, work);
> >  		wake_up_process(default_backing_dev_info.wb.task);
>=20
> Why not simply do the defaul thread wakeup under wb_lock, too?
> It keeps the code a lot simpler, and this is not a typical path anywa=
y.

Will address.

> >  		if (dirty_writeback_interval) {
> > +			unsigned long wait_jiffies;
> > +
> >  			wait_jiffies =3D msecs_to_jiffies(dirty_writeback_interval * 10=
);
> >  			schedule_timeout(wait_jiffies);
>=20
> No real need for a local variable here.

Will address.

> > @@ -364,7 +395,7 @@ static int bdi_forker_thread(void *ptr)
> >  		if (!list_empty(&me->bdi->work_list))
> >  			__set_current_state(TASK_RUNNING);
> > =20
> > -		if (!fork) {
> > +		if (!fork && !kill) {
>=20
> I think the code here would be a lot cleaner if you implement the
> suggestion I have for the forking restructuring.

As I replied earlier, to fork/kill the the thread from inside list walk
we'd need to drop the spinlock, which is not very nice. So I am keeping
this part intact so far.

--=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)