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,URIBL_BLOCKED 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 168B7C35247 for ; Thu, 6 Feb 2020 23:56:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B23E72068E for ; Thu, 6 Feb 2020 23:56:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="a57dANPf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B23E72068E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 42A6E6B0003; Thu, 6 Feb 2020 18:56:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DC086B0006; Thu, 6 Feb 2020 18:56:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F0FE6B0007; Thu, 6 Feb 2020 18:56:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id 1CC056B0003 for ; Thu, 6 Feb 2020 18:56:00 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B7A75246E for ; Thu, 6 Feb 2020 23:55:59 +0000 (UTC) X-FDA: 76461362838.23.power00_344cca2a03927 X-HE-Tag: power00_344cca2a03927 X-Filterd-Recvd-Size: 3542 Received: from mail-qv1-f68.google.com (mail-qv1-f68.google.com [209.85.219.68]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Thu, 6 Feb 2020 23:55:59 +0000 (UTC) Received: by mail-qv1-f68.google.com with SMTP id m5so168812qvv.4 for ; Thu, 06 Feb 2020 15:55:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=wfPvgghFf2DMJhy7eadDruUT5v7p4a/ZvJyom2rl9Po=; b=a57dANPf8EWe3YJhbkTClCTBrBFUaDTCV0iV+QivehVRNEcg9CL/EUY32PYUQnanJZ qAzSgKf3ZALLRbngIhfGb5khLDd4cZLBKBYOIsLHWu9wpRn0F02jcdIso2EQEtxYwFXD FXr8EHoW2dOr9Rvm97hVP8bmnP57sf/vycWbKg4phZaJtH9czqcZosnW6nsyGtCqFjsr xghw1RHZozmBj0TmviYOv+IbIcyllNfCu45HlGDdY6LrrzE7MRsWN4ApDgdOwMsilcoS qb64I8/Jh2crWOx+Ob5amurO0GDUyzrVxeIdm3PztalA+wU1/jBYFpbeiUw//k4CZlpp BjYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=wfPvgghFf2DMJhy7eadDruUT5v7p4a/ZvJyom2rl9Po=; b=Co3KlCU8jgmgvr3qJJtbb7yw2bvM35TTDup8WVso4NVsyoVG5/nwAgestPvsalEEKy gBoQXONkj/o34F9GBFhoFrktu5CUW4WsPpq7YbEdjRe0JQM6p7ZnuEZUYcI0H3ug8pvl ATi0xsUWWZNjsxbaQmAfFxSc66Q2+xyn30mEVdlVW483WYgpShOqLi2+HK0hF0JX06Jh s58MjElO/C7LLCwKc7BfmzI8obrAgZbQOADpJK/6IixSgSYRRnD7a0pmnKP/RkuOOAtT uLNOTMcILEmaSrnhCd/ClCFtxjKeLjdDfF3nT+2cDEyTcMQ8pLhQRkoTKXmchAtn4Bdy eOeQ== X-Gm-Message-State: APjAAAVg/ei/I0WPEuM8BtbiSjqwFToOiwDpvz0Uvijb5lzH5ZruYWb4 C+44/pJOn8pRvmZvqHgFkB/zKQ== X-Google-Smtp-Source: APXvYqyLv1a07nLKvYHfyJJThCFq1CF4peeEnd3zHiXWJDV3fk3XprrXrJa7fXlpLb6KzkW2DUC5HQ== X-Received: by 2002:ad4:4f47:: with SMTP id eu7mr4615264qvb.69.1581033358641; Thu, 06 Feb 2020 15:55:58 -0800 (PST) Received: from [192.168.1.183] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id g77sm429615qke.129.2020.02.06.15.55.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Feb 2020 15:55:58 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] mm: fix a data race in put_page() Date: Thu, 6 Feb 2020 18:55:57 -0500 Message-Id: References: <079c4429-8a11-154d-cf5c-473d2698d18d@nvidia.com> Cc: Jan Kara , David Hildenbrand , akpm@linux-foundation.org, ira.weiny@intel.com, dan.j.williams@intel.com, elver@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org In-Reply-To: <079c4429-8a11-154d-cf5c-473d2698d18d@nvidia.com> To: John Hubbard X-Mailer: iPhone Mail (17D50) X-Bogosity: Ham, tests=bogofilter, spamicity=0.008762, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Feb 6, 2020, at 6:34 PM, John Hubbard wrote: >=20 > * data_race(): there is no race on the N bits worth of page zone number da= ta. There > is only a perceived race, due to tools that look at word-level granularit= y. I=E2=80=99d like to think this from the compiler level. There is a data race= from the compiler load and store point of view. It is just in the case it i= s harmless to affect the actual code logic.=