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 D63CBC10DCE for ; Wed, 11 Mar 2020 00:04:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BA4921D56 for ; Wed, 11 Mar 2020 00:04:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="E2WEtHLm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727709AbgCKAEP (ORCPT ); Tue, 10 Mar 2020 20:04:15 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:36944 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726899AbgCKAEP (ORCPT ); Tue, 10 Mar 2020 20:04:15 -0400 Received: by mail-qk1-f196.google.com with SMTP id y126so435282qke.4 for ; Tue, 10 Mar 2020 17:04:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=kC2peWxJ+qm6+wzfyf0pDsl2H945cR1gyhQhbsBrJUE=; b=E2WEtHLmwgB1sqZ9NdN+PYhK/kzD9WlEKX/XMkqkvWCWgVvKOdHt3kMMRwtGfKRedx QsHdLUiE9T/DCGZnU+D3JmKEHaXbAlZw33XyyKsnL4XHMyDuuZcaq2W0rlKEV98nBwyh Q+YaCLmxO0cP74zP1i1WT34kG+5Y6HXbSFaP7yuHmRzWGFTGDRQ4I0VPFwEmU408GL9t YFrllVedIhQ7MkNwS5EzCYRzr3NTi8htqDcq920NygGPq565EI+nBd7M53aNAKuMiePM LSo5JbqR4rfT8Blrr8ChWL888Avah/D0nF/RIs3usG2MvXnSKLbhKaBlylwEX3uJkwrK lgbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=kC2peWxJ+qm6+wzfyf0pDsl2H945cR1gyhQhbsBrJUE=; b=PJlv4OzO9fB021yMGJqHtfmr0wDsBLfx0Tmb21f4mEbZ/dgP01ciSJTi7vrtVjqgSh QYi83oM0103Si8kQYiC9TfV/K++OvtDHsvnVa6VrpjKAEOMF3owfjNbSK2KieXEBY+NU qqYM+8QDdzzkZ+2UyhDarHI3/W3/5Dd05WJfjbhC7DdjT1S8BWmVN0wxSJ626qkLq2fv wjGB1xuUW/ofDEy4dZZbOT6BXwp9lFRLYuiIdEzKRnqrjQpEf1AvNaRafCp1c5PjPCFv BrEcM4UbLl70SFXch3cNC8Zesjw6GzTk4wcHvfCCsVf5NqviUXoLBAXV0Pch3hBs1D/z hV5Q== X-Gm-Message-State: ANhLgQ0UpKeAqU2QC+ZNK4QpSozJJiTGaQULlKoAWZxMJobaSm6IpwXM 49gV+EP4PH9b1XEqNWfXIFXg6A== X-Google-Smtp-Source: ADFU+vtmJ6y6O/Iq61etnzU2K2Cxevzv7kwYYoSGBz/QzRp5dQLU85KeY+jR709MQ0G+347olKfG2g== X-Received: by 2002:a05:620a:109a:: with SMTP id g26mr416744qkk.166.1583885053989; Tue, 10 Mar 2020 17:04:13 -0700 (PDT) Received: from [192.168.1.153] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id i28sm25764085qtc.57.2020.03.10.17.04.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Mar 2020 17:04:13 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.60.0.2.5\)) Subject: Re: [PATCH] mm, numa: fix bad pmd by atomically check for pmd_trans_huge when marking page tables prot_numa From: Qian Cai In-Reply-To: <20200309150531.GD25642@optiplex-lnx> Date: Tue, 10 Mar 2020 20:04:11 -0400 Cc: Linus Torvalds , Linux Memory Management List , LKML , mgorman , Andrew Morton , Michal Hocko , Vlastimil Babka Content-Transfer-Encoding: quoted-printable Message-Id: <917137D2-FD66-4175-AC69-23F8206186C5@lca.pw> References: <20200216191800.22423-1-aquini@redhat.com> <2E0766B8-DDD1-4448-8605-8535A16670FC@lca.pw> <20200307030530.GB4093@t490s> <9124C8B9-FB47-44F5-8606-DD9261BCB383@lca.pw> <20200308231423.GA22348@t490s> <20200309150531.GD25642@optiplex-lnx> To: Rafael Aquini X-Mailer: Apple Mail (2.3608.60.0.2.5) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Mar 9, 2020, at 11:05 AM, Rafael Aquini wrote: > I'm still waiting on a similar system to become available, so I can > work on your reproducer case, as well as to dig and wrap my head = around it. >=20 > I still don't think that skipping the pmd_none() in the = change-protection walk=20 > should cause a big fuss like you observed here (yet, it seems it = does), and=20 > the fact that we need that race window to take the __split_huge_pmd() = suggests, > at least to me, that we might be missing this proper split somewhere = else. I have sent out another patch which should be more correct, https://lore.kernel.org/lkml/20200310235846.1319-1-cai@lca.pw/=