Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753214AbcLEWKK (ORCPT ); Mon, 5 Dec 2016 17:10:10 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:34626 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752253AbcLEWKF (ORCPT ); Mon, 5 Dec 2016 17:10:05 -0500 Date: Mon, 5 Dec 2016 23:02:21 +0100 From: Pavel Machek To: Lino Sanfilippo Cc: Giuseppe CAVALLARO , alexandre.torgue@st.com, David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Message-ID: <20161205220221.GA19135@amd> References: <20161123105125.GA26394@amd> <20161124085506.GA25007@amd> <20161124.110416.198867271899443489.davem@davemloft.net> <20161124212540.GA24796@amd> <20161202084511.GA32294@amd> <3192a4b6-1e97-048f-a0dd-bfc0f3d96ed8@st.com> <20161205101516.GA24936@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uAKRQypu60I7Lcqm" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1285 Lines: 49 --uAKRQypu60I7Lcqm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >=20 > > Actually, I was wrong. irqlock protection is needed, since > > stmmac_tx_clean() is called from timer, and that's interrupt context, > > as you can confirm using BUG_ON(in_interrupt()); > >=20 >=20 > in_interrupt() can mean both softirq and hardirq context. In this case it > means softirq. So I guess you were right before, and no irq locking is ne= eded. Are you absolutely sure? Because my testing seems to indicate otherwise (but I may have made a mistake). According to https://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/c214.ht= ml we need spin_lock_bh at minimum, as we are locking user context against timer. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --uAKRQypu60I7Lcqm Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlhF4+0ACgkQMOfwapXb+vKCqACgoTqzIrl2YFvozduG2epyVzHd PiYAnAyPKui7xtlNQmpw4gVzUUI5Lqc7 =+ilP -----END PGP SIGNATURE----- --uAKRQypu60I7Lcqm--