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=-1.0 required=3.0 tests=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 69C3AC3F2CD for ; Thu, 5 Mar 2020 10:00:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 34D2F208CD for ; Thu, 5 Mar 2020 10:00:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 34D2F208CD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B2C9C6B0003; Thu, 5 Mar 2020 05:00:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B04EF6B0005; Thu, 5 Mar 2020 05:00:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A417F6B0007; Thu, 5 Mar 2020 05:00:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0157.hostedemail.com [216.40.44.157]) by kanga.kvack.org (Postfix) with ESMTP id 8D2116B0003 for ; Thu, 5 Mar 2020 05:00:26 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 81B37181AC9CC for ; Thu, 5 Mar 2020 10:00:26 +0000 (UTC) X-FDA: 76560863652.16.elbow84_3e03292fab809 X-HE-Tag: elbow84_3e03292fab809 X-Filterd-Recvd-Size: 3942 Received: from mail-wm1-f65.google.com (mail-wm1-f65.google.com [209.85.128.65]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Mar 2020 10:00:25 +0000 (UTC) Received: by mail-wm1-f65.google.com with SMTP id a132so5499404wme.1 for ; Thu, 05 Mar 2020 02:00:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=N+VHYLrvI+7e0ZVMs5A2YwvXMlQT1Gheq6HEnWaXrHg=; b=V83WwH5vI9ghn1TxIxXJrTN3N6neRGifA6xebUnAfDz7IWMz37CNIlvn6H/pYmDx/V Su+8iJSUYO+IAjYoJ1ewBBHFbOSkzA1DkXMjbfzg9GnyaeJe9zbutEHqyNykuLV5a73l Sl6pMffQWCw9/MJ1p2gy7Lvoto5SJgzdMzrMmfpLieJKDs1u7jq7NK7frCegsLvgIiRb wcl/CkCsDL106wbqweq45HhT75aaXk9l7W+lr4VXaQ7SHSGXsoMvDylobMKx2Cnv7HCA djq1f4nFnVww7fxCAWsLFlqWWiIgJtW5DFzraoZrFGu3prx2xtluGTZ+Lz/HjGiPrqFB S1ag== X-Gm-Message-State: ANhLgQ24r1sOqdCC6T4u+55HM1LakjcB/uq9NYTpsBPhVaSjNgRcMJNq 4j9bid+/ntOgzHsljMimsus= X-Google-Smtp-Source: ADFU+vsjaigYaEU+QZdTj0scvF+IN/q3UIp8DX+Zj1RxoQokICpr/pwGVXS7WJffS4KX2QC2pN6duQ== X-Received: by 2002:a1c:7c08:: with SMTP id x8mr8419345wmc.71.1583402424648; Thu, 05 Mar 2020 02:00:24 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id 25sm8514392wmg.30.2020.03.05.02.00.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Mar 2020 02:00:23 -0800 (PST) Date: Thu, 5 Mar 2020 11:00:23 +0100 From: Michal Hocko To: Vincenzo Frascino Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Vladimir Davydov , Andrew Morton Subject: Re: [PATCH] mm: Make mem_cgroup_id_get_many dependent on MMU and MEMCG_SWAP Message-ID: <20200305100023.GR16139@dhcp22.suse.cz> References: <20200304142348.48167-1-vincenzo.frascino@arm.com> <20200304165336.GO16139@dhcp22.suse.cz> <8c489836-b824-184e-7cfe-25e55ab73000@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8c489836-b824-184e-7cfe-25e55ab73000@arm.com> Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 05-03-20 09:49:23, Vincenzo Frascino wrote: > Hi Michal, >=20 > 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_SW= AP > >> configuration options are enabled. Having them disabled triggers the > >> following warning at compile time: > >> > >> linux/mm/memcontrol.c:4797:13: warning: =E2=80=98mem_cgroup_id_get_m= any=E2=80=99 defined > >> but not used [-Wunused-function] > >> static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsign= ed > >> int n) > >> > >> Make mem_cgroup_id_get_many() dependent on MMU and MEMCG_SWAP to add= ress > >> the issue. > >=20 > > A similar patch has been proposed recently > > http://lkml.kernel.org/r/87fthjh2ib.wl-kuninori.morimoto.gx@renesas.c= om. > > The conclusion was that the warning is not really worth adding code. > >=20 >=20 > Thank you for pointing this out, I was not aware of it. I understand th= at 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 ov= er 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. We have discussed __maybe_unused in the email thread as well. I am not a great fan of that as mentioed there. --=20 Michal Hocko SUSE Labs