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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 4FA1FC2BA2B for ; Mon, 13 Apr 2020 19:31:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EA13A20731 for ; Mon, 13 Apr 2020 19:31:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="vvLr0PCo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA13A20731 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chrisdown.name Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4BB018E0135; Mon, 13 Apr 2020 15:31:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4738A8E0104; Mon, 13 Apr 2020 15:31:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2E4978E0135; Mon, 13 Apr 2020 15:31:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0103.hostedemail.com [216.40.44.103]) by kanga.kvack.org (Postfix) with ESMTP id 174F18E0104 for ; Mon, 13 Apr 2020 15:31:14 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CCD1F180AD802 for ; Mon, 13 Apr 2020 19:31:13 +0000 (UTC) X-FDA: 76703825226.19.milk38_27cce6e37f816 X-HE-Tag: milk38_27cce6e37f816 X-Filterd-Recvd-Size: 3773 Received: from mail-wm1-f65.google.com (mail-wm1-f65.google.com [209.85.128.65]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Mon, 13 Apr 2020 19:31:13 +0000 (UTC) Received: by mail-wm1-f65.google.com with SMTP id g12so3329540wmh.3 for ; Mon, 13 Apr 2020 12:31:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=+1oIAGp/+mYXSIibcKMNOMtcUpS8aqG4LNCJREQx4I0=; b=vvLr0PCo3ceEpektVTQVrt0+tx94n9iBTlGZAK0bjFj/z9kb8ZLiWacNCe2ovRkYDT cqOTXc2bCABkHPKafkdRaCpUWJs0kvwVhY5edDr5xdnOe/nbMibOHRjEi0kINxp+kLCb lKVPejbfruG/nFaxDR1iyxn4c+Dh4XO/cyw28= 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:in-reply-to; bh=+1oIAGp/+mYXSIibcKMNOMtcUpS8aqG4LNCJREQx4I0=; b=FcoNRNQcUAYLcyLSffAotLIvJK8kWyV2256nul8UGG4KuSjRbvRvruppjDMhIK7KIu rUeK5GTrSnSkkmTMXrhHAw+MEBIBdH7yE2AnIEVVJ3KsPl2OAxrqW19llWum1IwcoRyt LME9SiDMZAn4StKd4KNB7MeD6ECQ9YtTW7C3CZXzQ9mlj7TVZ8vAbZ7I/BaMyxOdyg3e K87wFNgbvmYwNGnnq4p0doqdj7A8kG81sN0iB+rlc3aIeZLVvvKrqsGH/EeXbO0TvG4F gIOCqZZn6zeLWVS7iHib6bGlkXmMTcTG1gitHmmErGm90ogPcTMmJXMjfYDMcLnaGbJm i4fw== X-Gm-Message-State: AGi0PuYVuIlp41puL9ycZOMeRzxNgBcspXl9a11LB7y0Lm1Nun7imoMx ELUvRzyuq0O6m7WTnXUJSkq8mw== X-Google-Smtp-Source: APiQypJ/mpnsEUj9pgbNcu3Pv9+/pt/Nlq9mWca5Q620EPZGmW/XoR58jV5Qp4yL6uvl0K4Q65v1QQ== X-Received: by 2002:a1c:3b09:: with SMTP id i9mr19450264wma.19.1586806272067; Mon, 13 Apr 2020 12:31:12 -0700 (PDT) Received: from localhost ([2a01:4b00:8432:8a00:fa59:71ff:fe7e:8d21]) by smtp.gmail.com with ESMTPSA id v10sm3754208wrq.45.2020.04.13.12.31.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Apr 2020 12:31:11 -0700 (PDT) Date: Mon, 13 Apr 2020 20:31:11 +0100 From: Chris Down To: Yafang Shao Cc: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, akpm@linux-foundation.org, linux-mm@kvack.org, Shakeel Butt , stable@vger.kernel.org Subject: Re: [PATCH] mm, memcg: fix inconsistent oom event behavior Message-ID: <20200413193111.GA1559372@chrisdown.name> References: <20200412140427.6732-1-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200412140427.6732-1-laoar.shao@gmail.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000005, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Yafang, Yafang Shao writes: >A recent commit 9852ae3fe529 ("mm, memcg: consider subtrees in >memory.events") changes the behavior of memcg events, which will >consider subtrees in memory.events. But oom_kill event is a special one >as it is used in both cgroup1 and cgroup2. In cgroup1, it is displayed >in memory.oom_control. The file memory.oom_control is in both root memcg >and non root memcg, that is different with memory.event as it only in >non-root memcg. That commit is okay for cgroup2, but it is not okay for >cgroup1 as it will cause inconsistent behavior between root memcg and >non-root memcg. >Let's recover the original behavior for cgroup1. Can you please explain the practical ramifications of this and show an explicitly laid out example of how this manifests, with numbers and scenarios? It's unclear to me that this is a real problem as is -- it may be, but there certainly needs to be more information. Thanks, Chris