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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 391E9C2BA19 for ; Fri, 24 Apr 2020 00:50:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EEBD22087E for ; Fri, 24 Apr 2020 00:50:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VMXQGgTx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEBD22087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 984B88E0005; Thu, 23 Apr 2020 20:50:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 935188E0003; Thu, 23 Apr 2020 20:50:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 823398E0005; Thu, 23 Apr 2020 20:50:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0093.hostedemail.com [216.40.44.93]) by kanga.kvack.org (Postfix) with ESMTP id 6887F8E0003 for ; Thu, 23 Apr 2020 20:50:16 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1B1FE181AC9B6 for ; Fri, 24 Apr 2020 00:50:16 +0000 (UTC) X-FDA: 76740917232.02.skate44_3c853331a560d X-HE-Tag: skate44_3c853331a560d X-Filterd-Recvd-Size: 3895 Received: from mail-il1-f193.google.com (mail-il1-f193.google.com [209.85.166.193]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Fri, 24 Apr 2020 00:50:15 +0000 (UTC) Received: by mail-il1-f193.google.com with SMTP id i16so7696455ils.12 for ; Thu, 23 Apr 2020 17:50:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DH+1wZRFcAGugGUmHt8yA2LS6AHEpgK1G4ZlJe1XPRQ=; b=VMXQGgTx7+K/Em1P83QYLS414PnUEe61KtkU2fgIvtDkyZWw/7tzsAUOYZD4+rJUlp jL9BSfo5L4JSkP10d4OQi1NbJAqFDVUEwe7cWxwGZb0CVUYvSIyIvewXQv9KLHPfuLDp g8V8kMgbXhVqhdzCKx7HWgUJWjinSKqvQpAcGJt1rV7ZKzMJf0tzSc6Z/2mR6XlUE7Cz ICff4Aqp7sYHi0XPhlV7fhzkfSii9mHlssTn7KVHOJpX4E9oTSmRsBP72SoSDoPMEVRM Ft9TybbLUpUyJk8mopOeYOo1a/9o6/pgRnLSjC8On3I3M0v+n4K0OV7y7oOQ2X35EBi3 M5Eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DH+1wZRFcAGugGUmHt8yA2LS6AHEpgK1G4ZlJe1XPRQ=; b=iDYLBJsN1rg99qSRfwg0BU7AJ7/Vhen2M2kiAUWTQkgZKcKPgM49Twe0c+L7ae8YBn d+kP1lXI/N3UCODrST4ISPgpnS+T5+Kaeuto+cpaZISKmFR2wKdNB8H85CooTypoETVj C4xDle/Qamh/2D5cmYTvZb3VEHdR06j3x8JonW55iI1iY8Ap5vQpqTFzXPyndhDzIqWx 22pozH6PtDqHnLZB7qanFj0zwHEnNpbOCotNugx4y0VabzNuLUG64PbAHBUM6QabeLNE YBpKk/wxWG591HCdvEtHtx5ScJJST6dX2Ru/lOhuoiTMCwKoJn1x/NKhpNprTkgTHrg8 qa9w== X-Gm-Message-State: AGi0PuazA0H4VFOxz7Nolvvmp/YdPGQ6uOW+cZpbQ8urCG1hIRJPBopL b5jVY3Hbk0K8ukd53EQsqcCIrRszttmAAA8W4zI= X-Google-Smtp-Source: APiQypKIgHCGiEpeXA+KLO8dYsM6xOSLsa/ChQtYmxiRH78xTuvjsRNT4OP9jLukE2QcPVu7dTZZF1hxiQpHD3EKJJU= X-Received: by 2002:a92:5c57:: with SMTP id q84mr6354958ilb.203.1587689415194; Thu, 23 Apr 2020 17:50:15 -0700 (PDT) MIME-Version: 1.0 References: <20200423061629.24185-1-laoar.shao@gmail.com> <20200423153323.GA1318256@chrisdown.name> In-Reply-To: <20200423153323.GA1318256@chrisdown.name> From: Yafang Shao Date: Fri, 24 Apr 2020 08:49:39 +0800 Message-ID: Subject: Re: [PATCH] mm, memcg: fix wrong mem cgroup protection To: Chris Down Cc: Andrew Morton , Michal Hocko , Vladimir Davydov , Linux MM , Roman Gushchin , stable@vger.kernel.org, Johannes Weiner Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Apr 23, 2020 at 11:33 PM Chris Down wrote: > > Hi Yafang, > > I'm afraid I'm just as confused as Michal was about the intent of this patch. > > Can you please be more concise and clear about the practical ramifications and > demonstrate some pathological behaviour? I really can't visualise what's wrong > here from your explanation, and if I can't understand it as the person who > wrote this code, I am not surprised others are also confused :-) > Hi Chris, 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. > Or maybe Roman can try to explain, since he acked the previous patch? At least > to me, the emin/elow behaviour seems fairly non-trivial to reason about right > now. > -- Thanks Yafang