Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757461AbcCCNEa (ORCPT ); Thu, 3 Mar 2016 08:04:30 -0500 Received: from casper.infradead.org ([85.118.1.10]:37887 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbcCCNE2 (ORCPT ); Thu, 3 Mar 2016 08:04:28 -0500 Date: Thu, 3 Mar 2016 14:04:24 +0100 From: Peter Zijlstra To: Juri Lelli Cc: "Rafael J. Wysocki" , Linux PM list , Steve Muckle , ACPI Devel Maling List , Linux Kernel Mailing List , Srinivas Pandruvada , Viresh Kumar , Vincent Guittot , Michael Turquette Subject: Re: [PATCH 1/6] cpufreq: Reduce cpufreq_update_util() overhead a bit Message-ID: <20160303130424.GP6356@twins.programming.kicks-ass.net> References: <2495375.dFbdlAZmA6@vostro.rjw.lan> <3575770.L1lplNLqVv@vostro.rjw.lan> <20160303114701.GT18792@e106622-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160303114701.GT18792@e106622-lin> 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: 348 Lines: 12 On Thu, Mar 03, 2016 at 11:47:01AM +0000, Juri Lelli wrote: > > +#ifdef CONFIG_LOCKDEP > > + WARN_ON(debug_locks && !rcu_read_lock_sched_held()); > > +#endif > > > > data = rcu_dereference(*this_cpu_ptr(&cpufreq_update_util_data)); > > I think you need to s/rcu_dereference/rcu_dereference_sched/ here or > RCU will complain: Ah, indeed ;-)