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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 C0905C433E0 for ; Wed, 6 Jan 2021 06:51:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E4B22076D for ; Wed, 6 Jan 2021 06:51:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726427AbhAFGvN (ORCPT ); Wed, 6 Jan 2021 01:51:13 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:43354 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725788AbhAFGvM (ORCPT ); Wed, 6 Jan 2021 01:51:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609915786; h=from:from:reply-to:subject:subject: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=mpnSCXynfZDg9JxezxrI3YVJuV9OmtsTh1Ys0ZNSFcs=; b=GHTiqaFdu19lIuNdyyGZZXf5wmHZvRSMEQR1gqx7ri/5Q/iowHLbf0R1gaEQuT09zbBm4F UwgrPgdWuvIvvn0vsp2/MtJFL82CvkBRqi6B9ZOTwbh4GzqqF2UK363gEIQ3MbGP7FIRIc sw3AqU9syOJ5i9hLEfTLQWAczhQ1KaM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-212-zZL9C3A1ND6CFuicSxuRDQ-1; Wed, 06 Jan 2021 01:49:40 -0500 X-MC-Unique: zZL9C3A1ND6CFuicSxuRDQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DC6798015C3; Wed, 6 Jan 2021 06:49:38 +0000 (UTC) Received: from localhost (ovpn-12-186.pek2.redhat.com [10.72.12.186]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E46805D9CD; Wed, 6 Jan 2021 06:49:37 +0000 (UTC) Date: Wed, 6 Jan 2021 14:49:35 +0800 From: Baoquan He To: Hugh Dickins Cc: Andrew Morton , Hui Su , Alex Shi , Lorenzo Stoakes , Michal Hocko , Johannes Weiner , Shakeel Butt , Roman Gushchin , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/memcontrol: fix warning in mem_cgroup_page_lruvec() Message-ID: <20210106064935.GA3338@MiWiFi-R3L-srv> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/03/21 at 09:03pm, Hugh Dickins wrote: > Boot a CONFIG_MEMCG=y kernel with "cgroup_disabled=memory" and you are > met by a series of warnings from the VM_WARN_ON_ONCE_PAGE(!memcg, page) > recently added to the inline mem_cgroup_page_lruvec(). > > An earlier attempt to place that warning, in mem_cgroup_lruvec(), had > been careful to do so after weeding out the mem_cgroup_disabled() case; > but was itself invalid because of the mem_cgroup_lruvec(NULL, pgdat) in > clear_pgdat_congested() and age_active_anon(). > > Warning in mem_cgroup_page_lruvec() was once useful in detecting a KSM > charge bug, so may be worth keeping: but skip if mem_cgroup_disabled(). > > Fixes: 9a1ac2288cf1 ("mm/memcontrol:rewrite mem_cgroup_page_lruvec()") > Signed-off-by: Hugh Dickins > --- > > include/linux/memcontrol.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- 5.11-rc2/include/linux/memcontrol.h 2020-12-27 20:39:36.751923135 -0800 > +++ linux/include/linux/memcontrol.h 2021-01-03 19:38:24.822978559 -0800 > @@ -665,7 +665,7 @@ static inline struct lruvec *mem_cgroup_ > { > struct mem_cgroup *memcg = page_memcg(page); > > - VM_WARN_ON_ONCE_PAGE(!memcg, page); > + VM_WARN_ON_ONCE_PAGE(!memcg && !mem_cgroup_disabled(), page); > return mem_cgroup_lruvec(memcg, pgdat); Thanks for fixing this. We also encountered this issue in kdump kernel with the mainline 5.10 kernel since 'cgroup_disable=memory' is added. Reviewed-by: Baoquan He