From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754499Ab3KKP7h (ORCPT ); Mon, 11 Nov 2013 10:59:37 -0500 Received: from merlin.infradead.org ([205.233.59.134]:37432 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753926Ab3KKP7b (ORCPT ); Mon, 11 Nov 2013 10:59:31 -0500 Date: Mon, 11 Nov 2013 16:59:05 +0100 From: Peter Zijlstra To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, ak@linux.intel.com, acme@redhat.com, jolsa@redhat.com, zheng.z.yan@intel.com, bp@alien8.de, maria.n.dimakopoulou@gmail.com Subject: Re: [PATCH v6 3/4] perf,x86: add Intel RAPL PMU support Message-ID: <20131111155905.GM19203@twins.programming.kicks-ass.net> References: <1383939963-7750-1-git-send-email-eranian@google.com> <1383939963-7750-4-git-send-email-eranian@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1383939963-7750-4-git-send-email-eranian@google.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 On Fri, Nov 08, 2013 at 08:46:02PM +0100, Stephane Eranian wrote: > +static DEFINE_SPINLOCK(rapl_hotplug_lock); What is this thing protecting? Like last time it appears to be used only from hotplug notifier callbacks and those are already fully serialized.