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 ECA01C433E1 for ; Tue, 25 Aug 2020 12:03:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0E8220706 for ; Tue, 25 Aug 2020 12:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729027AbgHYMDN convert rfc822-to-8bit (ORCPT ); Tue, 25 Aug 2020 08:03:13 -0400 Received: from foss.arm.com ([217.140.110.172]:57188 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725893AbgHYMAS (ORCPT ); Tue, 25 Aug 2020 08:00:18 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EC1B01FB; Tue, 25 Aug 2020 05:00:17 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F9B13F66B; Tue, 25 Aug 2020 05:00:16 -0700 (PDT) References: <20200824153902.57875-1-andriy.shevchenko@linux.intel.com> <20200825082636.GQ1891694@smile.fi.intel.com> <20200825112405.GU1891694@smile.fi.intel.com> <20200825112605.GV1891694@smile.fi.intel.com> <20200825113202.GX1891694@smile.fi.intel.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Andy Shevchenko 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 In-reply-to: <20200825113202.GX1891694@smile.fi.intel.com> Date: Tue, 25 Aug 2020 13:00:12 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/08/20 12:32, Andy Shevchenko wrote: > On Tue, Aug 25, 2020 at 02:26:05PM +0300, Andy Shevchenko wrote: >> 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. > > And even without compiler or any other analyzer / bot I can 100% sure tell that > spi.c does *not* use that symbol. Aye aye, this is a daft constvar placement from my end, apologies. For the SD_DEGENERATE_GROUPS_MASK, that one could directly be shoved into kernel/sched/topology.c (or done via an enum, I don't care too much). I suppose the other one causing you grief is sd_flag_debug[]; that one too really shouldn't be in a header. I need to access that in two separate files, so I guess I'll have to cook up some wrappers. Let me take a jab at it, it's my own mess after all...