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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 D5A5CC43387 for ; Mon, 17 Dec 2018 16:51:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A66E02145D for ; Mon, 17 Dec 2018 16:51:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388295AbeLQQvB (ORCPT ); Mon, 17 Dec 2018 11:51:01 -0500 Received: from ale.deltatee.com ([207.54.116.67]:33222 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbeLQQvB (ORCPT ); Mon, 17 Dec 2018 11:51:01 -0500 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1gYw6H-0002lM-Kq; Mon, 17 Dec 2018 09:50:38 -0700 To: Nick Kossifidis Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-sh@vger.kernel.org, Rob Herring , Albert Ou , Andrew Waterman , Arnd Bergmann , Palmer Dabbelt , Stephen Bates , Zong Li , Olof Johansson , Andrew Morton , Michael Clark , Christoph Hellwig References: <20181015175702.9036-1-logang@deltatee.com> <20181015175702.9036-7-logang@deltatee.com> <4b591ba933363e29392dba218ef63267@mailhost.ics.forth.gr> From: Logan Gunthorpe Message-ID: <5fd0880c-5896-ffee-4d3c-4fce1649382e@deltatee.com> Date: Mon, 17 Dec 2018 09:50:30 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <4b591ba933363e29392dba218ef63267@mailhost.ics.forth.gr> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: hch@lst.de, michaeljclark@mac.com, akpm@linux-foundation.org, olof@lixom.net, zong@andestech.com, sbates@raithlin.com, palmer@sifive.com, arnd@arndb.de, andrew@sifive.com, aou@eecs.berkeley.edu, robh@kernel.org, linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mick@ics.forth.gr X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v2 6/6] RISC-V: Implement sparsemem X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-12-17 7:59 a.m., Nick Kossifidis wrote: > Having memory blocks of a minimum size of 1GB doesn't make much sense. > It makes it harder to implement hotplug on top of this since we'll only > able to add/remove 1GB at a time. ARM used to do the same and they > switched to 27bits (https://patchwork.kernel.org/patch/9172845/), ARM64 > still uses 1GB, x86 also uses 27bits and most archs also use something > below 30. I believe we should go for 27bits as well or even better have > this as a compile time option. Thanks, that makes sense. I'll make the change for the next time we submit. > BTW memblocks_present is on master now (got merged 3 days ago). Great! We'll send an updated patch set after the merge window. Logan