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 A78C2C55191 for ; Fri, 24 Apr 2020 12:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 887EC20700 for ; Fri, 24 Apr 2020 12:18:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="oXb1uRcV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726698AbgDXMSl (ORCPT ); Fri, 24 Apr 2020 08:18:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726667AbgDXMSk (ORCPT ); Fri, 24 Apr 2020 08:18:40 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61618C09B045 for ; Fri, 24 Apr 2020 05:18:39 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id f13so10481009wrm.13 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=oycLVfVAHSpf5PIJqCPF2MUfXfj+AIppMAFVdc8iOI/cG5GT5bS7TQ4tnFoHL3KBss CQVWfO61oWgvFMGs0Xj+kbwyh/vm0wDa6dAssm/WUgl6OIDDXSRZHMqpKhQmXVJp64J0 sf7KmnUZ2yIgnnY3hwN8APnDdrSS0BjsnEeE5X6bWAbOTR2Tr8vXg7tDTNcvTYcA3g61 /3/0ShYCO0pEyKSunPdwxhnlT0VkgnkIz+f/KeexbDtBWHEcTGAUQZsFqq7xR45j6uWk uRmJ1Eo/DD+vWfF60ROml205JQaCV4buWE+umtQMQtFpLY/KUpP84/g6kf1aCxBsKfyU RVuw== X-Gm-Message-State: AGi0Pubrw1UmH4EQjNpspBEsxPMVqWt/9abXP9FNM5skRxNKAiXj9Awh G7k4cFfn0mUl0iNLXOJAgT+KhQ== 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: Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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.