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=-5.8 required=3.0 tests=BAYES_00,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 560E1C433DB for ; Fri, 8 Jan 2021 19:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D83B23AA7 for ; Fri, 8 Jan 2021 19:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728917AbhAHT0W (ORCPT ); Fri, 8 Jan 2021 14:26:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728864AbhAHT0W (ORCPT ); Fri, 8 Jan 2021 14:26:22 -0500 Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92B36C061381 for ; Fri, 8 Jan 2021 11:25:41 -0800 (PST) Received: by mail-lf1-x12a.google.com with SMTP id l11so25637835lfg.0 for ; Fri, 08 Jan 2021 11:25:41 -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=Wbp5uQXvEJj9vCd3uDLsS0MjLHCz/E8hBRej1ogMfSY=; b=CnoSYFDonWZ+Dgr+tiFEJynbekbzhxxmwqhGZRLPn7gyBa+bQCxiZCgqtJNAqqH7V7 TSFbUq82vxW5E7FhsuzaQeerMwZaOt0+C5QPZm1zSWCjM30scQoh2y1t/I0kXtd2Me5o PnboSZjV2P4J6KnmAMWXW033tv1LqjZapysIM= 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=Wbp5uQXvEJj9vCd3uDLsS0MjLHCz/E8hBRej1ogMfSY=; b=dEqjKp11esznCczAvaaFUB4Z+FAsBhb24PQ1GIblcwF4Nv+SW0/MhrNuITzUZW7C2L KhI2iAI63dK4tItgQnvk/dYF02lqOrIY0oX6zmub8tAC4Ui83D47xS/X/HumyFFQeY2+ Qd81ETLnT3y3WbKWb4S+2MpWgxa9nFHlPXmTRlrDR/lUc7wDr0IpUT1HNTeq6uYSz7IC gxdxNPZProy/x0BCDrXm19lZYTqa8lauMyBG4RfZy1wI+LuBL9gEngjQ3G5uO9qI7tzP qHqt2dA8cHjvIhZv/LNVCFjAD/ae+mG8b12EmWD4J9fSdSUbXyLDSRPnnstWxlwfKQG+ 0HtA== X-Gm-Message-State: AOAM53300IGNj6qq71ZrEWOcQIniIcHflC0wTMiLVk7S1PIPzkx9i71N 2BSFitXi9hZ7chWSj+gclA1A6dCSt1IEog== X-Google-Smtp-Source: ABdhPJzR9jNbshrafTEJ5wdjnILqlN06XI6ZpmyDCddxY96H0D1MyVQR7LQd1PFyn2A0krtUcoMGMA== X-Received: by 2002:a05:6512:208c:: with SMTP id t12mr2366268lfr.165.1610133939798; Fri, 08 Jan 2021 11:25:39 -0800 (PST) Received: from mail-lf1-f47.google.com (mail-lf1-f47.google.com. [209.85.167.47]) by smtp.gmail.com with ESMTPSA id y4sm2113903lfl.179.2021.01.08.11.25.38 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 Jan 2021 11:25:38 -0800 (PST) Received: by mail-lf1-f47.google.com with SMTP id x20so25436021lfe.12 for ; Fri, 08 Jan 2021 11:25:38 -0800 (PST) X-Received: by 2002:a2e:9b13:: with SMTP id u19mr2008203lji.48.1610133938011; Fri, 08 Jan 2021 11:25:38 -0800 (PST) MIME-Version: 1.0 References: <20210108124815.GA4512@willie-the-truck> In-Reply-To: From: Linus Torvalds Date: Fri, 8 Jan 2021 11:25:21 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/2] mm: soft_dirty: userfaultfd: introduce wrprotect_tlb_flush_pending To: Andrea Arcangeli Cc: Will Deacon , Linux-MM , Linux Kernel Mailing List , Yu Zhao , Andy Lutomirski , Peter Xu , Pavel Emelyanov , Mike Kravetz , Mike Rapoport , Minchan Kim , Peter Zijlstra , Hugh Dickins , "Kirill A. Shutemov" , Matthew Wilcox , Oleg Nesterov , Jann Horn , Kees Cook , John Hubbard , Leon Romanovsky , Jason Gunthorpe , Jan Kara , Kirill Tkhai , Nadav Amit , Andrew Morton Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 8, 2021 at 9:53 AM Andrea Arcangeli wrote: > > Do you intend to eventually fix the zygote vmsplice case or not? > Because in current upstream it's not fixed currently using the > enterprise default config. Is this the hugepage case? Neither of your patches actually touched that, so I've forgotten the details. > Irrelevant special case as in: long term GUP pin on the memory? Irrelevant special case in that (a) an extra COW shouldn't be a correctness issue unless somebody does something horribly wrong (and obviously the code that hasn't taken the mmap_lock for writing are then examples of that) and (b) it's not a performance issue either unless you can find a real load that does it. Hmm? Linus