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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 48ADDC63777 for ; Tue, 17 Nov 2020 05:32:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0045E246BE for ; Tue, 17 Nov 2020 05:32:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726537AbgKQFca (ORCPT ); Tue, 17 Nov 2020 00:32:30 -0500 Received: from outpost1.zedat.fu-berlin.de ([130.133.4.66]:46347 "EHLO outpost1.zedat.fu-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726339AbgKQFc3 (ORCPT ); Tue, 17 Nov 2020 00:32:29 -0500 X-Greylist: delayed 449 seconds by postgrey-1.27 at vger.kernel.org; Tue, 17 Nov 2020 00:32:28 EST Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.94) with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (envelope-from ) id 1ketU5-001CTB-2k; Tue, 17 Nov 2020 06:24:53 +0100 Received: from p57bd9382.dip0.t-ipconnect.de ([87.189.147.130] helo=[192.168.178.139]) by inpost2.zedat.fu-berlin.de (Exim 4.94) with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (envelope-from ) id 1ketU4-000ZYQ-Qv; Tue, 17 Nov 2020 06:24:52 +0100 Subject: Re: [PATCH v2 00/13] arch, mm: deprecate DISCONTIGMEM To: Mike Rapoport , Andrew Morton Cc: Alexey Dobriyan , Catalin Marinas , Geert Uytterhoeven , Greg Ungerer , Jonathan Corbet , Matt Turner , Meelis Roos , Michael Schmitz , Mike Rapoport , Russell King , Tony Luck , Vineet Gupta , Will Deacon , linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mm@kvack.org, linux-snps-arc@lists.infradead.org References: <20201101170454.9567-1-rppt@kernel.org> From: John Paul Adrian Glaubitz Message-ID: <43c53597-6267-bdc2-a975-0aab5daa0d37@physik.fu-berlin.de> Date: Tue, 17 Nov 2020 06:24:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201101170454.9567-1-rppt@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 87.189.147.130 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi! On 11/1/20 6:04 PM, Mike Rapoport wrote: > It's been a while since DISCONTIGMEM is generally considered deprecated, > but it is still used by four architectures. This set replaces DISCONTIGMEM > with a different way to handle holes in the memory map and marks > DISCONTIGMEM configuration as BROKEN in Kconfigs of these architectures with > the intention to completely remove it in several releases. > > While for 64-bit alpha and ia64 the switch to SPARSEMEM is quite obvious > and was a matter of moving some bits around, for smaller 32-bit arc and > m68k SPARSEMEM is not necessarily the best thing to do. > > On 32-bit machines SPARSEMEM would require large sections to make section > index fit in the page flags, but larger sections mean that more memory is > wasted for unused memory map. > > Besides, pfn_to_page() and page_to_pfn() become less efficient, at least on > arc. > > So I've decided to generalize arm's approach for freeing of unused parts of > the memory map with FLATMEM and enable it for both arc and m68k. The > details are in the description of patches 10 (arc) and 13 (m68k). Apologies for the late reply. Is this still relevant for testing? I have already successfully tested v1 of the patch set, shall I test v2? Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaubitz@debian.org `. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913