From mboxrd@z Thu Jan  1 00:00:00 1970
From: Artem Bityutskiy <dedekind1@gmail.com>
Subject: Re: [PATCHv4 17/17] writeback: lessen sync_supers wakeup count
Date: Thu, 27 May 2010 13:19:03 +0300
Message-ID: <1274955543.32558.11.camel@localhost>
References: <1274795352-3551-1-git-send-email-dedekind1@gmail.com>
	 <1274795352-3551-18-git-send-email-dedekind1@gmail.com>
	 <20100527065041.GA31073@ZenIV.linux.org.uk>
Reply-To: dedekind1@gmail.com
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: LKML <linux-kernel@vger.kernel.org>,
	Jens Axboe <jens.axboe@oracle.com>,
	linux-fsdevel@vger.kernel.org
To: Al Viro <viro@ZenIV.linux.org.uk>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20100527065041.GA31073@ZenIV.linux.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

On Thu, 2010-05-27 at 07:50 +0100, Al Viro wrote:
> On Tue, May 25, 2010 at 04:49:12PM +0300, Artem Bityutskiy wrote:
> > From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> > +void mark_sb_dirty(struct super_block *sb)
> > +{
> > +	sb->s_dirty =3D 1;
> > +
> > +	spin_lock(&supers_timer_lock);
> > +	if (!supers_timer_armed) {
> > +		bdi_arm_supers_timer();
> > +		supers_timer_armed =3D 1;
> > +	} else if (supers_timer_armed =3D=3D -1)
> > +		supers_timer_armed =3D 1;
> > +	spin_unlock(&supers_timer_lock);
> > +}
> > +EXPORT_SYMBOL(mark_sb_dirty);
>=20
> Ouch...   That turns a previously trivial operation into something
> much heavier; moreover, I'd rather see serious review of s_dirt
> uses.

OK, I'll try to do something lighter with atomic variables or something
like Nick posted - need to think about this. And I'll try to review
s_dirty usage as much as my time and knowledge allow. Thanks.

--=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)