Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756237Ab3JNMD1 (ORCPT ); Mon, 14 Oct 2013 08:03:27 -0400 Received: from merlin.infradead.org ([205.233.59.134]:54688 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755979Ab3JNMD0 (ORCPT ); Mon, 14 Oct 2013 08:03:26 -0400 Date: Mon, 14 Oct 2013 14:03:06 +0200 From: Peter Zijlstra To: Juri Lelli Cc: tglx@linutronix.de, mingo@redhat.com, rostedt@goodmis.org, oleg@redhat.com, fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch, linux-kernel@vger.kernel.org, claudio@evidence.eu.com, michael@amarulasolutions.com, fchecconi@gmail.com, tommaso.cucinotta@sssup.it, nicola.manica@disi.unitn.it, luca.abeni@unitn.it, dhaval.giani@gmail.com, hgu1972@gmail.com, paulmck@linux.vnet.ibm.com, raistlin@linux.it, insop.song@gmail.com, liming.wang@windriver.com, jkacur@redhat.com, harald.gustafsson@ericsson.com, vincent.guittot@linaro.org, bruce.ashfield@windriver.com--no-chain-reply-to Subject: Re: [PATCH 04/14] sched: SCHED_DEADLINE SMP-related data structures & logic. Message-ID: <20131014120306.GH3081@twins.programming.kicks-ass.net> References: <1381747426-31334-1-git-send-email-juri.lelli@gmail.com> <1381747426-31334-5-git-send-email-juri.lelli@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381747426-31334-5-git-send-email-juri.lelli@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 Content-Length: 811 Lines: 25 On Mon, Oct 14, 2013 at 12:43:36PM +0200, Juri Lelli wrote: > +static inline void dl_set_overload(struct rq *rq) > +{ > + if (!rq->online) > + return; > + > + cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask); > + /* > + * Must be visible before the overload count is > + * set (as in sched_rt.c). > + */ > + wmb(); > + atomic_inc(&rq->rd->dlo_count); > +} Please, make that smp_wmb() and modify the comment to point to the matching barrier ; I couldn't find one! Which suggests something is amiss. Ideally we'd have something like smp_wmb__after_set_bit() but alas. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/