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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CC37BC3F2CD for ; Thu, 5 Mar 2020 09:49:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9EC2F2073D for ; Thu, 5 Mar 2020 09:49:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726861AbgCEJtE (ORCPT ); Thu, 5 Mar 2020 04:49:04 -0500 Received: from foss.arm.com ([217.140.110.172]:46020 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725897AbgCEJtE (ORCPT ); Thu, 5 Mar 2020 04:49:04 -0500 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 B221531B; Thu, 5 Mar 2020 01:49:03 -0800 (PST) Received: from [192.168.1.161] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 420DB3F6C4; Thu, 5 Mar 2020 01:49:02 -0800 (PST) Subject: Re: [PATCH] mm: Make mem_cgroup_id_get_many dependent on MMU and MEMCG_SWAP To: Michal Hocko Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Vladimir Davydov , Andrew Morton References: <20200304142348.48167-1-vincenzo.frascino@arm.com> <20200304165336.GO16139@dhcp22.suse.cz> From: Vincenzo Frascino Message-ID: <8c489836-b824-184e-7cfe-25e55ab73000@arm.com> Date: Thu, 5 Mar 2020 09:49:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200304165336.GO16139@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michal, On 3/4/20 4:53 PM, Michal Hocko wrote: > On Wed 04-03-20 14:23:48, Vincenzo Frascino wrote: >> mem_cgroup_id_get_many() is currently used only when MMU or MEMCG_SWAP >> configuration options are enabled. Having them disabled triggers the >> following warning at compile time: >> >> linux/mm/memcontrol.c:4797:13: warning: ‘mem_cgroup_id_get_many’ defined >> but not used [-Wunused-function] >> static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned >> int n) >> >> Make mem_cgroup_id_get_many() dependent on MMU and MEMCG_SWAP to address >> the issue. > > A similar patch has been proposed recently > http://lkml.kernel.org/r/87fthjh2ib.wl-kuninori.morimoto.gx@renesas.com. > The conclusion was that the warning is not really worth adding code. > Thank you for pointing this out, I was not aware of it. I understand that you are against "#ifdeffery" in this case, but isn't it the case of adding at least __maybe_unused? This would prevent people from reporting it over and over again and you to have to push them back :) Let me know what do you think, in case I am happy to change my patch accordingly. [...] -- Regards, Vincenzo