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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 00905C63798 for ; Tue, 17 Nov 2020 06:23:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EA3B223BD for ; Tue, 17 Nov 2020 06:23:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qAUA5RVC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726756AbgKQGX2 (ORCPT ); Tue, 17 Nov 2020 01:23:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:42812 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725355AbgKQGX1 (ORCPT ); Tue, 17 Nov 2020 01:23:27 -0500 Received: from kernel.org (unknown [77.125.7.142]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7DA1C223AB; Tue, 17 Nov 2020 06:23:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605594206; bh=i6knV0DMO2RXQJYhiZxatZGtoKHulkxOl5sSaGDS0gM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qAUA5RVCTP0npaeRBIO8YpdBuUTgIPD0QBwHOr2UeiElqlVtKRczsIc13jS9qXhSM /m8cTkIY+QMvxEbuFwI36fTIAAvpIJ9fhQtB5SdUWJTnAGZetOklMyr9EQ9DA4BJIQ QteWhvERMCEW1EUrOIOHXVbp4uevZfdG2TI7hGQ8= Date: Tue, 17 Nov 2020 08:23:16 +0200 From: Mike Rapoport To: John Paul Adrian Glaubitz Cc: Andrew Morton , 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 Subject: Re: [PATCH v2 00/13] arch, mm: deprecate DISCONTIGMEM Message-ID: <20201117062316.GB370813@kernel.org> References: <20201101170454.9567-1-rppt@kernel.org> <43c53597-6267-bdc2-a975-0aab5daa0d37@physik.fu-berlin.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43c53597-6267-bdc2-a975-0aab5daa0d37@physik.fu-berlin.de> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Adrian, On Tue, Nov 17, 2020 at 06:24:51AM +0100, John Paul Adrian Glaubitz wrote: > 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? There were minor differences only for m68k between the versions. I've verified them on ARAnyM but if you have a real machine a run there would be nice. > 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 > > -- Sincerely yours, Mike.