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=-5.7 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,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 E360BC432BE for ; Thu, 12 Aug 2021 18:29:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 82CE8610CF for ; Thu, 12 Aug 2021 18:29:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 82CE8610CF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D339D8D0002; Thu, 12 Aug 2021 14:29:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CBD8C8D0001; Thu, 12 Aug 2021 14:29:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B5DF18D0002; Thu, 12 Aug 2021 14:29:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0077.hostedemail.com [216.40.44.77]) by kanga.kvack.org (Postfix) with ESMTP id 9D2A18D0001 for ; Thu, 12 Aug 2021 14:29:51 -0400 (EDT) Received: from smtpin40.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3F1BA1EA0F for ; Thu, 12 Aug 2021 18:29:51 +0000 (UTC) X-FDA: 78467267382.40.0A965EF Received: from mail-ed1-f47.google.com (mail-ed1-f47.google.com [209.85.208.47]) by imf21.hostedemail.com (Postfix) with ESMTP id B5824D021694 for ; Thu, 12 Aug 2021 18:29:50 +0000 (UTC) Received: by mail-ed1-f47.google.com with SMTP id i6so11149307edu.1 for ; Thu, 12 Aug 2021 11:29:50 -0700 (PDT) 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=IkXJUR2wo/lfdijzxf9i2+gB15K2x3AMKk03NvuHrAg=; b=DgletMF3GIx03R+Prc+kYYByk45jic0DRscnKADZUoHI1P+YyPtvtoPTQ7QnJ7IPQd SXOSwOUdkx2aiZaMFMOp1dhadasdgIRxU7GtFMCT7AGdEYsSqpb/znDsiIrZCbOQNfg4 VzUm5rt2KFFchQnCpyiuGLbfU1kLNH4SQV4x0= 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=IkXJUR2wo/lfdijzxf9i2+gB15K2x3AMKk03NvuHrAg=; b=lXv46augnMUQvWNjL3Y3xsOZ3wx4LFTJAEZQrg9C9yyKwHEm59tf1KOia5TQFxtE4T pu2upRqlAofLjTVi7Ourd0dz4YUY00EowJ/HyDzq1gkoYsNn9YOTmc6sZrTi/BPElGTR /1cMaeayCvLIssoN9IYSpRLaFbKOYHlnDe5SKziTJ/esedZvBSCGdQ87/UI5Qn1IfHhe J9dzBjAQQj3QWU88TOeUtrBpEWpaRhn024PBC9fAi/YGyXjAVY3dq2xxTKLcklbIucea OSxXhT7/+cNMN8Rk/KboaeFnc+1a7nzNxaYDole2puZNy56J/3kfrOR3fUCRiJ2NyVse DPPg== X-Gm-Message-State: AOAM533RSxD32E5kilVQRsm7Onq83KoqHEIqUoK359mptwndyl2E5ZwL d05llqK6weNb+9CjLY9Emst8W1m0X0npqCVrA64= X-Google-Smtp-Source: ABdhPJxUUTNxaZh5z6grfFumItZlajEmhBvReP4cG1NAbafGLfRRbNa+hAB3PoYIDLYHC8LCcF+wfA== X-Received: by 2002:aa7:da4a:: with SMTP id w10mr7166907eds.206.1628792989272; Thu, 12 Aug 2021 11:29:49 -0700 (PDT) Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com. [209.85.221.44]) by smtp.gmail.com with ESMTPSA id s18sm1147863ejh.12.2021.08.12.11.29.49 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Aug 2021 11:29:49 -0700 (PDT) Received: by mail-wr1-f44.google.com with SMTP id q18so2710520wrm.6 for ; Thu, 12 Aug 2021 11:29:49 -0700 (PDT) X-Received: by 2002:a2e:944c:: with SMTP id o12mr3785844ljh.411.1628792497006; Thu, 12 Aug 2021 11:21:37 -0700 (PDT) MIME-Version: 1.0 References: <20210812084348.6521-1-david@redhat.com> <87o8a2d0wf.fsf@disp2133> <60db2e61-6b00-44fa-b718-e4361fcc238c@www.fastmail.com> <87lf56bllc.fsf@disp2133> <87lf56edgz.fsf@oldenburg.str.redhat.com> In-Reply-To: <87lf56edgz.fsf@oldenburg.str.redhat.com> From: Linus Torvalds Date: Thu, 12 Aug 2021 08:21:20 -1000 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 0/7] Remove in-tree usage of MAP_DENYWRITE To: Florian Weimer Cc: "Eric W. Biederman" , Andy Lutomirski , David Hildenbrand , Linux Kernel Mailing List , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Al Viro , Alexey Dobriyan , Steven Rostedt , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Michel Lespinasse , Catalin Marinas , "Matthew Wilcox (Oracle)" , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Collin Fijalkovich , Michal Hocko , Miklos Szeredi , Chengguang Xu , =?UTF-8?Q?Christian_K=C3=B6nig?= , linux-unionfs@vger.kernel.org, Linux API , "the arch/x86 maintainers" , linux-fsdevel , Linux-MM Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=DgletMF3; dmarc=none; spf=pass (imf21.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.47 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org X-Stat-Signature: 4yq8837jzhgpfbspd8r1ssygp4u7mt89 X-Rspamd-Queue-Id: B5824D021694 X-Rspamd-Server: rspam05 X-HE-Tag: 1628792990-886548 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 12, 2021 at 8:16 AM Florian Weimer wrote: > > I think this is called MAP_COPY: > > Please don't even consider the crazy notions that GNU Hurd did. It's a fundamental design mistake. The Hurd VM was horrendous, and MAP_COPY was a prime example of the kinds of horrors it had. I'm not sure how much of the mis-designs were due to Hurd, and how much of it due to Mach 3. But please don't point to Hurd VM documentation except possibly to warn people. We want people to _forget_ those mistakes, not repeat them. Linus