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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 62DC7C433E0 for ; Wed, 24 Feb 2021 09:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B56664EBA for ; Wed, 24 Feb 2021 09:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234613AbhBXJcI (ORCPT ); Wed, 24 Feb 2021 04:32:08 -0500 Received: from mx2.suse.de ([195.135.220.15]:55904 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232563AbhBXJbo (ORCPT ); Wed, 24 Feb 2021 04:31:44 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1614159058; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RHDb1EdzW6ls0b9fIDV8fGOOuVEVrb7XhiXVWuec/l4=; b=sdh8e/w5oTQCb745WEPHxOHWYf5r0wxjB/z4beRQ4u39gmoCbGLGEmfsRGI/HaRqjS4Kmh YIK7mWaAXmjWIOSgk8wZ8aFvrivXgmVghdLlilVsChCKuTF/XPP7ZwytmBizpe8HCFizS8 ZBToJTW5QZiLS+U7WWzpcvk663uYC9s= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 60CA8AE05; Wed, 24 Feb 2021 09:30:58 +0000 (UTC) Date: Wed, 24 Feb 2021 10:30:57 +0100 From: Michal Hocko To: Shakeel Butt Cc: Johannes Weiner , Roman Gushchin , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] memcg: cleanup root memcg checks Message-ID: References: <20210223205625.2792891-1-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210223205625.2792891-1-shakeelb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 23-02-21 12:56:25, Shakeel Butt wrote: > Replace the implicit checking of root memcg with explicit root memcg > checking i.e. !css->parent with mem_cgroup_is_root(). > > Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Thanks! > --- > mm/memcontrol.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index dcb5665aeb69..79046ad3eec0 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4141,7 +4141,7 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, > if (val > 100) > return -EINVAL; > > - if (css->parent) > + if (!mem_cgroup_is_root(memcg)) > memcg->swappiness = val; > else > vm_swappiness = val; > @@ -4491,7 +4491,7 @@ static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, > struct mem_cgroup *memcg = mem_cgroup_from_css(css); > > /* cannot set to root cgroup and only 0 and 1 are allowed */ > - if (!css->parent || !((val == 0) || (val == 1))) > + if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1))) > return -EINVAL; > > memcg->oom_kill_disable = val; > -- > 2.30.0.617.g56c4b15f3c-goog -- Michal Hocko SUSE Labs