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=-0.8 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 51E8DC54FD0 for ; Fri, 24 Apr 2020 12:18:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F08AE20700 for ; Fri, 24 Apr 2020 12:18:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="oXb1uRcV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F08AE20700 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 498C48E0005; Fri, 24 Apr 2020 08:18:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4499D8E0003; Fri, 24 Apr 2020 08:18:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 35EFD8E0005; Fri, 24 Apr 2020 08:18:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id 1BE418E0003 for ; Fri, 24 Apr 2020 08:18:40 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C9D0F6100 for ; Fri, 24 Apr 2020 12:18:39 +0000 (UTC) X-FDA: 76742651958.17.rule03_68b2abefdd70a X-HE-Tag: rule03_68b2abefdd70a X-Filterd-Recvd-Size: 4023 Received: from mail-wr1-f68.google.com (mail-wr1-f68.google.com [209.85.221.68]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 24 Apr 2020 12:18:39 +0000 (UTC) Received: by mail-wr1-f68.google.com with SMTP id d17so10509914wrg.11 for ; Fri, 24 Apr 2020 05:18:39 -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=ipnrAc+3cHuR7HETpLSOZ/5pb3ou/GVUIiWBM3QfP6g=; b=oXb1uRcV2TeRQZCyd2HB+GxacyKPmMxcmjkLte3Sr9bBviXfK0IoR739gYNHZ9Yxf7 DNr0j345PtdEonwsua9UDFDZjp8vGhGAMP/PzLxaAzB0lnkjTqv1AjS+21a7nGBYTxGk o8SfE+AnlTC4o0q52FcxEkOFUFrlirhzEY4rs= 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=ipnrAc+3cHuR7HETpLSOZ/5pb3ou/GVUIiWBM3QfP6g=; b=Y2DArYIo3wKA0X2OrjJodzPCa9dYNVg2QDlUSUFaqeO3VZLGFe+4s8qJBR05s1GkG+ E3ob37iLJDYTXkWECQrNFRwn2i0wCL3YpeboeEkjM1RetVz9ZsBb+snMnhZXBZyxH0O4 FDMHRfn0Osg0pmCGYpcCvnJqi2YnIykub934pxwrb3SLbZpH8B8KMXqlgQQ+aUdARLzm n+p4to7LyF+KnN5DtdgwK+CuLbDBelHpdWcO/H7Us/hY8m4VYcOdIHmGsrNcDP4Hnt6t W3u54DdVdM6loyvW/QBQMu/FDsrjx2TyOEiO97Bb24Csx5mHJrCeFUWXR4H75aUjNZHZ y1ow== X-Gm-Message-State: AGi0PuaCjY84xe9nJQu2jZdyBLM9y1iNN2Y4pb+Gp66zU/QJDBvdDk+6 DhW81oJnPfUTG4znT0kT/adVCg== X-Google-Smtp-Source: APiQypK3jlRPBnbzBDYDGr5uzrtczZ4y7sMSF3ZqM2froUtG5ZL3FCYUnhBNyfri73DaJTjbZ/jiHQ== X-Received: by 2002:adf:e5c7:: with SMTP id a7mr11138306wrn.241.1587730718065; Fri, 24 Apr 2020 05:18:38 -0700 (PDT) Received: from localhost ([2a01:4b00:8432:8a00:56e1:adff:fe3f:49ed]) by smtp.gmail.com with ESMTPSA id p6sm8083667wrt.3.2020.04.24.05.18.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2020 05:18:37 -0700 (PDT) Date: Fri, 24 Apr 2020 13:18:36 +0100 From: Chris Down To: Yafang Shao Cc: Andrew Morton , Michal Hocko , Vladimir Davydov , Linux MM , Roman Gushchin , stable@vger.kernel.org, Johannes Weiner Subject: Re: [PATCH] mm, memcg: fix wrong mem cgroup protection Message-ID: <20200424121836.GA1379200@chrisdown.name> References: <20200423061629.24185-1-laoar.shao@gmail.com> <20200423153323.GA1318256@chrisdown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000754, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Yafang Shao writes: >If the author can't understand deeply in the code worte by >himself/herself, I think the author should do more test on his/her >patches. >Regarding the issue in this case, my understanding is you know the >benefit of proportional reclaim, but I'm wondering that do you know >the loss if the proportional is not correct ? >I don't mean to affend you, while I just try to explain how the >community should cooperate. I'm pretty sure that since multiple people on mm list have already expressed confusion at this patch, this isn't a question of testing, but of lack of clarity in usage :-) Promoting "testing" as a panacea for this issue misses a significant part of the real problem: that the intended semantics and room for allowed races is currently unclear, which is why there is a general sense of confusion around your proposed patch and what it solves. If more testing would help, then the benefit of your patch should be patently obvious -- but it isn't.