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[2604:1380:45d1:ec00::1]) by mx.google.com with ESMTPS id op53-20020a05620a537500b00788258b007esi9350465qkn.715.2024.03.07.03.12.28 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Mar 2024 03:12:28 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-95390-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1; Authentication-Results: mx.google.com; arc=pass (i=1); spf=pass (google.com: domain of linux-kernel+bounces-95390-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) smtp.mailfrom="linux-kernel+bounces-95390-linux.lists.archive=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id 2D1721C20EDA for ; Thu, 7 Mar 2024 11:12:28 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 129F812B154; Thu, 7 Mar 2024 11:11:03 +0000 (UTC) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0A2F12AACA; Thu, 7 Mar 2024 11:10:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.201.40.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709809862; cv=none; b=XN9RNUVpc9HZ1/ZrPBuJWfSaG8hg1N86bZLxQLPyNymo2yo1bq1Pju18W5/xDJ3Qf3QVxkiwGe5HJmUPOHZxhCkj+n52F+M+8hxtClGXOgddSueOUazR6CoDtR0USfOiCcvdfOUaX87Z05VElCLYztvpTwc8Gj7BfCxBQ5FKK34= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709809862; c=relaxed/simple; bh=d9qXCwBy0OCnjmukXXQYfDDhyk8g3sbgN8e6gFFm7+o=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: MIME-Version:Content-Type; b=rDG9HdqDrnRrgXWucIZD8DXUU4F1x7hTYdTHgyGFTb8ue1fpnMrmUDlcvrEkgUFsQTHOCdX9EHPHh/pHgh0D4uwy9lcWOM5dBbRMxUri8vya0zM9Vky2iXCyCGw/zDmPZdIeAQwBZhAV/KADuF21KZ9k1TJNyzlZ9ZTn+EPKawo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=nod.at; spf=fail smtp.mailfrom=nod.at; arc=none smtp.client-ip=195.201.40.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=nod.at Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nod.at Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 56BBB644CE85; Thu, 7 Mar 2024 12:10:58 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id UdxeGAjGXPBj; Thu, 7 Mar 2024 12:10:57 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 84261644CE7E; Thu, 7 Mar 2024 12:10:57 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id JXqFNTpdyqQP; Thu, 7 Mar 2024 12:10:57 +0100 (CET) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id 4C4FE644CE85; Thu, 7 Mar 2024 12:10:57 +0100 (CET) Date: Thu, 7 Mar 2024 12:10:57 +0100 (CET) From: Richard Weinberger To: David Hildenbrand Cc: linux-mm , linux-fsdevel , linux-kernel , Linux Doc Mailing List , upstream+pagemap@sigma-star.at, adobriyan@gmail.com, wangkefeng wang , ryan roberts , hughd@google.com, peterx@redhat.com, avagin@google.com, lstoakes@gmail.com, vbabka , Andrew Morton , usama anjum , Jonathan Corbet Message-ID: <861682210.23281.1709809857201.JavaMail.zimbra@nod.at> In-Reply-To: References: <20240306232339.29659-1-richard@nod.at> <20240306232339.29659-2-richard@nod.at> Subject: Re: [PATCH 2/2] [RFC] pagemap.rst: Document write bit Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF97 (Linux)/8.8.12_GA_3809) Thread-Topic: pagemap.rst: Document write bit Thread-Index: m4Aa6cZ4OAmz6WBRgPq7/2CUVSqXkA== ----- Urspr=C3=BCngliche Mail ----- > Von: "David Hildenbrand" > An: "richard" , "linux-mm" >> + Bit 58 is useful to detect CoW mappings; however, it does not indica= te >> + whether the page mapping is writable or not. If an anonymous mapping= is >> + writable but the write bit is not set, it means that the next write = access >> + will cause a page fault, and copy-on-write will happen. >=20 > That is not true. Can you please help me correct my obvious misunderstanding?