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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 01C01C433DB for ; Fri, 8 Jan 2021 19:36:20 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8896423A9D for ; Fri, 8 Jan 2021 19:36:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8896423A9D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oo3Ec8zoJ7AEiHOtYzZAaucgliJtHw5jGe8CSFUBJ3c=; b=109q+Fhl1oovbaEcPg1PdQ539 +ia4QjMnv00AcLPS1uEV+sDWTZx/qJBf7xshADNloD13CWbr4VV/xWQCKvg0GCY5VaNKU8aAzYAjX bjgzYZqDeBDjdK7/zMWLXt73l8hhsvINOaUcDGrEj9LHO9eAKM0wxCvbzjQ7wd5kkpydegi5UGxVa 1i14fE6f/hqjn/ocdIOw1Cpa1cYANjLZDabG6ZLNl7cPwsJ3xarm6XpgLA5WYgl9FFOFk7tBdo7U6 ARywsVsD5Dyft+4+MkYzdNqzs7xzL7AHsnAUvcq+hUzPDHMb8M6Au27CJ/8ixb+eFK404C63jqvjP zYUu6CkCw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxxX5-0006Ku-Cf; Fri, 08 Jan 2021 19:34:47 +0000 Received: from mail-lf1-x12f.google.com ([2a00:1450:4864:20::12f]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxxWm-0006Dk-Ew for linux-arm-kernel@lists.infradead.org; Fri, 08 Jan 2021 19:34:45 +0000 Received: by mail-lf1-x12f.google.com with SMTP id o19so25642910lfo.1 for ; Fri, 08 Jan 2021 11:34:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=t+MJWRxDTU36V8xE19m5WjjSjbefnbmENuppDaMSAKg=; b=WhBZKnikJ7D+9OF0OeU9baHQ4dnixiMFFXPibHM5X49KiX9Ewm7jxNN5GWUiTkR5xU /Ai8HlPNgCtZp7Y6PHdYR0cKx3eNJ6hyPyLd/NXT/eNP/2htauiFUzovR6ePM0cZ32sN zrEq5XGLLpxSteRwMBBZP5CMTtHvGKLevDWuo= 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=t+MJWRxDTU36V8xE19m5WjjSjbefnbmENuppDaMSAKg=; b=ZPra5/R8t4ZxxO7YpUVhxSZvSfT9+G+3ZcYVQikMhadEFM/6BE2xldfN/dG8dnYIp1 XzVgmCJ2f+52hFAMN9ZEgXR93RPOm68zu2ssdZ2imZEOGeUzTXTkZGlNanlxhE7EJJtr sZphzXYJx+0UGOtmtVhCjqomIUKLXgbZTAntp6989NXH8Tym4c465ONiWTZW6n8A/uLt RPz0+AKd2t0xTWoFUpvgOUSImGoYVc7CiOoU7CnUzgJ9qInJHFTKkbEBPemVx8FgSlN3 +DrJKhvQE/tH/+jJScTzU6yiSsxrk277uG+QQfqfeWC0/9N+OajXrfsAb9D/zPa4FARI aKzA== X-Gm-Message-State: AOAM532pZOMPPZ7A3mbZe56kNZHgUJRw4df2GHC7WbZX5zmHUmqc5m9K +LcPbRe6V5OKdG9+H/HfnQHsnOreVSLZHA== X-Google-Smtp-Source: ABdhPJzb1MABVb/PelTsk57Tjk3hswkwOITiX/1DDHHk6nfdfhj9nwUeTD/ljsFlbWZ5leiIslMaBg== X-Received: by 2002:a05:651c:551:: with SMTP id q17mr2011001ljp.311.1610134466095; Fri, 08 Jan 2021 11:34:26 -0800 (PST) Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com. [209.85.167.51]) by smtp.gmail.com with ESMTPSA id j7sm2109636lfe.165.2021.01.08.11.34.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 Jan 2021 11:34:25 -0800 (PST) Received: by mail-lf1-f51.google.com with SMTP id l11so25696042lfg.0 for ; Fri, 08 Jan 2021 11:34:25 -0800 (PST) X-Received: by 2002:a2e:9ad7:: with SMTP id p23mr2022603ljj.465.1610134464854; Fri, 08 Jan 2021 11:34:24 -0800 (PST) MIME-Version: 1.0 References: <20210108171517.5290-1-will@kernel.org> In-Reply-To: <20210108171517.5290-1-will@kernel.org> From: Linus Torvalds Date: Fri, 8 Jan 2021 11:34:08 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 0/3] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag To: Will Deacon X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210108_143428_631995_9D1EDC96 X-CRM114-Status: GOOD ( 16.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jan Kara , Minchan Kim , Catalin Marinas , Hugh Dickins , Linux Kernel Mailing List , Linux-MM , Vinayak Menon , "Kirill A . Shutemov" , Andrew Morton , Android Kernel Team , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 8, 2021 at 9:15 AM Will Deacon wrote: > > The big difference in this version is that I have reworked it based on > Kirill's patch which he posted as a follow-up to the original. However, > I can't tell where we've landed on that -- Linus seemed to like it, but > Hugh was less enthusiastic. Yeah, I like it, but I have to admit that it had a disturbingly high number of small details wrong for several versions. I hope you picked up the final version of the code. At the same time, I do think that the "disturbingly high number of issues" was primarily exactly _because_ the old code was so incomprehensible, and I think the end result is much cleaner, so I still like it. >I think that my subsequent patches are an > awful lot cleaner after the rework Yeah, I think that's a side effect of "now the code really makes a lot more sense". Your subsequent patches 2-3 certainly are much simpler now, although I'd be inclined to add an argument to "do_set_pte()" that has the "write" and "pretault" bits in it, instead of having to modify the 'vmf' structure. I still dislike how we basically randomly modify the information in that 'vmf' thing. That said, now it's just a small detail - not really objectionable, just a "this could be cleaner, I think". I think it was Kirill who pointed out that we sadly cannot make 'vmf' read-only anyway, because it does also contain those pre-allocation details etc (vmf->pte etc) that are very much about what the current "state" of the fault is. So while I would hope it could be more read-only than it is, my wish that it could _actually_ be 'const' is clearly just an irrelevant dream. Linus _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel