From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31D64C433DF for ; Tue, 25 Aug 2020 11:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14C9820715 for ; Tue, 25 Aug 2020 11:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729985AbgHYL0g (ORCPT ); Tue, 25 Aug 2020 07:26:36 -0400 Received: from mga03.intel.com ([134.134.136.65]:21487 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729878AbgHYL0U (ORCPT ); Tue, 25 Aug 2020 07:26:20 -0400 IronPort-SDR: TAZ2jWpt8aSi+c7bhltOxbnpOox+QQ1ayN0d9zceJu6EAlfcYdOPnSe0Xv3mtpRA7VzjI2h2ja 4dGoZEwUGXLQ== X-IronPort-AV: E=McAfee;i="6000,8403,9723"; a="156081716" X-IronPort-AV: E=Sophos;i="5.76,352,1592895600"; d="scan'208";a="156081716" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2020 04:26:10 -0700 IronPort-SDR: 6njZOvBY1izLogjrobnUCx6enPHeHsLp5OjBK/HwLAvABspPgPwJ5lMJ9vQlcpjPct+HnP9Vmc hdhUmn5SVMaw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,352,1592895600"; d="scan'208";a="328838043" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga008.jf.intel.com with ESMTP; 25 Aug 2020 04:26:07 -0700 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1kAX5Z-00BJNP-2l; Tue, 25 Aug 2020 14:26:05 +0300 Date: Tue, 25 Aug 2020 14:26:05 +0300 From: Andy Shevchenko To: Valentin Schneider Cc: Ingo Molnar , Peter Zijlstra , Vincent Guittot , linux-kernel@vger.kernel.org, Dietmar Eggemann Subject: Re: [PATCH v1] sched/topology: Make compiler happy about unused constant definitions Message-ID: <20200825112605.GV1891694@smile.fi.intel.com> References: <20200824153902.57875-1-andriy.shevchenko@linux.intel.com> <20200825082636.GQ1891694@smile.fi.intel.com> <20200825112405.GU1891694@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200825112405.GU1891694@smile.fi.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 25, 2020 at 02:24:05PM +0300, Andy Shevchenko wrote: > On Tue, Aug 25, 2020 at 11:12:21AM +0100, Valentin Schneider wrote: > > On 25/08/20 10:03, Valentin Schneider wrote: > > > On 25/08/20 09:26, Andy Shevchenko wrote: > > >> On Mon, Aug 24, 2020 at 06:09:41PM +0100, Valentin Schneider wrote: > > >>> On 24/08/20 16:39, Andy Shevchenko wrote: > > >>> > Compilation of almost each file ends up with > > >>> > > > >>> > In file included from .../include/linux/energy_model.h:10, > > >>> > from .../include/linux/device.h:16, > > >>> > from .../drivers/spi/spi.c:8: > > >>> > .../include/linux/sched/topology.h:30:27: warning: ‘SD_DEGENERATE_GROUPS_MASK’ defined but not used [-Wunused-const-variable=] > > >>> > 30 | static const unsigned int SD_DEGENERATE_GROUPS_MASK = > > >>> > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > > >>> > ... > > >>> > > > >>> > Make compiler happy by annotating the static constants with __maybwe_unused. > > > > > Sorry, that's what I get for trying to be too succinct; what I tried to say > > > was that SD_DEGENERATE_GROUPS_MASK should very much be used for SMP. If the > > > build is !SMP, it shouldn't even be defined, IOW I'm perplexed as to where > > > this is coming from. > > > > So I see how having this as a constvar rather than a constexpr is somewhat > > daft (we get an instance per compilation unit), but none of my compilers > > seem to complain (even with W=1). AFAIA the kernelbot didn't catch any of > > it either. > > > > Out of curiosity, what's your compiler & compiler version? > > % gcc --version > gcc (Debian 10.2.0-5) 10.2.0 > > % make O=... W=1 C=1 CF=-D__CHECK_ENDIAN__ -j64 > > > Alternatively we can make this a "proper" constant expression with the > > below. > > It doesn't fix another static const in the same file, though that one requires > DEBUG_SCHED to be enabled. > > Do you want me to split this fix and fix only the other case? Just checked and the other case has been brought by b6e862f38672 ("sched/topology: Define and assign sched_domain flag metadata") with your authorship. -- With Best Regards, Andy Shevchenko