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, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 8753DC433DB for ; Thu, 25 Feb 2021 11:56:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F009764F13 for ; Thu, 25 Feb 2021 11:56:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F009764F13 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ghiti.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5A6DA8D001A; Thu, 25 Feb 2021 06:56:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 558418D0005; Thu, 25 Feb 2021 06:56:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 494D58D001A; Thu, 25 Feb 2021 06:56:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0053.hostedemail.com [216.40.44.53]) by kanga.kvack.org (Postfix) with ESMTP id 320788D0005 for ; Thu, 25 Feb 2021 06:56:22 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E18BB81534E6 for ; Thu, 25 Feb 2021 11:56:21 +0000 (UTC) X-FDA: 77856637362.23.D4F6084 Received: from relay12.mail.gandi.net (relay12.mail.gandi.net [217.70.178.232]) by imf13.hostedemail.com (Postfix) with ESMTP id 719ACE000108 for ; Thu, 25 Feb 2021 11:56:18 +0000 (UTC) Received: from [192.168.43.237] (35.161.185.81.rev.sfr.net [81.185.161.35]) (Authenticated sender: alex@ghiti.fr) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 85E2B200008; Thu, 25 Feb 2021 11:56:12 +0000 (UTC) Subject: Re: [PATCH 2/3] Documentation: riscv: Add documentation that describes the VM layout To: David Hildenbrand , Jonathan Corbet , Paul Walmsley , Palmer Dabbelt , Albert Ou , Arnd Bergmann , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-mm@kvack.org References: <20210225080453.1314-1-alex@ghiti.fr> <20210225080453.1314-3-alex@ghiti.fr> <5279e97c-3841-717c-2a16-c249a61573f9@redhat.com> From: Alex Ghiti Message-ID: <7d9036d9-488b-47cc-4673-1b10c11baad0@ghiti.fr> Date: Thu, 25 Feb 2021 06:56:11 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <5279e97c-3841-717c-2a16-c249a61573f9@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr X-Stat-Signature: byq69igfg93r6f8jrki5t8xm1ayjq6og X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 719ACE000108 Received-SPF: none (ghiti.fr>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=relay12.mail.gandi.net; client-ip=217.70.178.232 X-HE-DKIM-Result: none/none X-HE-Tag: 1614254178-273979 Content-Transfer-Encoding: quoted-printable 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: Le 2/25/21 =C3=A0 5:34 AM, David Hildenbrand a =C3=A9crit=C2=A0: > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0 |> +=20 > ffffffc000000000 | -256=C2=A0=C2=A0=C2=A0 GB | ffffffc7ffffffff |=C2=A0= =C2=A0 32 GB | kasan >> +=C2=A0=C2=A0 ffffffcefee00000 | -196=C2=A0=C2=A0=C2=A0 GB | ffffffcef= effffff |=C2=A0=C2=A0=C2=A0 2 MB | fixmap >> +=C2=A0=C2=A0 ffffffceff000000 | -196=C2=A0=C2=A0=C2=A0 GB | ffffffcef= fffffff |=C2=A0=C2=A0 16 MB | PCI io >> +=C2=A0=C2=A0 ffffffcf00000000 | -196=C2=A0=C2=A0=C2=A0 GB | ffffffcff= fffffff |=C2=A0=C2=A0=C2=A0 4 GB | vmemmap >> +=C2=A0=C2=A0 ffffffd000000000 | -192=C2=A0=C2=A0=C2=A0 GB | ffffffdff= fffffff |=C2=A0=C2=A0 64 GB |=20 >> vmalloc/ioremap space >> +=C2=A0=C2=A0 ffffffe000000000 | -128=C2=A0=C2=A0=C2=A0 GB | ffffffff7= fffffff |=C2=A0 126 GB |=20 >> direct mapping of all physical memory >=20 > ^ So you could never ever have more than 126 GB, correct? >=20 > I assume that's nothing new. >=20 Before this patch, the limit was 128GB, so in my sense, there is nothing=20 new. If ever we want to increase that limit, we'll just have to lower=20 PAGE_OFFSET, there is still some unused virtual addresses after kasan=20 for example. Thanks, Alex