From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754239AbaENJJK (ORCPT ); Wed, 14 May 2014 05:09:10 -0400 Received: from casper.infradead.org ([85.118.1.10]:48300 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751557AbaENJJH (ORCPT ); Wed, 14 May 2014 05:09:07 -0400 Date: Wed, 14 May 2014 11:09:03 +0200 From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , Andrew Morton , Ingo Molnar , Kevin Hilman , "Paul E. McKenney" , Thomas Gleixner , Viresh Kumar Subject: Re: [PATCH 3/3] nohz: Use IPI implicit full barrier against rq->nr_running r/w Message-ID: <20140514090903.GD30445@twins.programming.kicks-ass.net> References: <1400019956-25511-1-git-send-email-fweisbec@gmail.com> <1400019956-25511-4-git-send-email-fweisbec@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="GaDTZZn2ADWB060d" Content-Disposition: inline In-Reply-To: <1400019956-25511-4-git-send-email-fweisbec@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --GaDTZZn2ADWB060d Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 14, 2014 at 12:25:56AM +0200, Frederic Weisbecker wrote: > @@ -670,10 +670,11 @@ bool sched_can_stop_tick(void) > =20 > rq =3D this_rq(); > =20 > - /* Make sure rq->nr_running update is visible after the IPI */ > - smp_rmb(); > - > - /* More than one running task need preemption */ > + /* > + * More than one running task need preemption. > + * nr_running update is assumed to be visible > + * after IPI is sent from wakers. > + */ > if (rq->nr_running > 1) > return false; Looks like whitespace damage on that comment's indenting. --GaDTZZn2ADWB060d Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTczKvAAoJEHZH4aRLwOS6zpUP/jOEN7ZcCRk9jvKs+bc7ZWar a4G/I7/NtdR0ZYeqGBOAjpmrdVNdWCYbbqQJ87fTghikXNjuMYc7O3rIZO7Dcqpy HbjE2dO1mNPyc/MB5Cr9xMUDbIsGIp1nSjeQG9YZYMCXmPHdUAg0f7mVPshw/vaJ Bn1Z96KxFKdVpaPJsGQdcbA3eRCAY0u4Wwf5D73C2SQJGezG8jDzlLijxb+WT8Ok PqVgAGwaBjVu0z7ASOY8uFZaSrkcDI0Z8SrXCvpxMRLqsvRm4BaUu6DE8R/1B0Ng aZm/mnYuvxPPwBaBW0sDbG+XTJf7U2OWZhJfdH6/IsFhHvJs5h3nVLQiRIWU2VB1 P267A1pCI4FkA8bdw6B9vdpURxR8P+pttjztwZTjYOfEDGXuzLV7jELK90p9x3Cd jNJ5sCIWMXHbb2dkpxmhNFpGmNWLupNiniGr0XhPbbe286kcjDx/G9V5dmmd4qKW iUpp2w5gy43xJrPqVP1Aq4NHF49G1Em/RMlfBXodJ68Fboiht3WXPzMDzNtsxCK6 26K5OfR/oL8AO6xhxSC1O8Gbuo6vuwHf9U92SRXdRhIchcs9Ut0I2DVB4j4igDLR 73hnsN4des2FtDe0ZGChm8vMN9uhDe9LuHoGMN8/cg4b2zFEzjovQ+t8sAzQn78H wNVl9usICIeQDpTGvUiL =CvlI -----END PGP SIGNATURE----- --GaDTZZn2ADWB060d--