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=-8.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 8EA7CC433DF for ; Mon, 24 Aug 2020 10:39:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AD8B2067C for ; Mon, 24 Aug 2020 10:39:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726977AbgHXKj1 (ORCPT ); Mon, 24 Aug 2020 06:39:27 -0400 Received: from mx2.suse.de ([195.135.220.15]:57344 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725999AbgHXKjV (ORCPT ); Mon, 24 Aug 2020 06:39:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 4CF8EAC98; Mon, 24 Aug 2020 10:39:50 +0000 (UTC) Date: Mon, 24 Aug 2020 12:39:18 +0200 From: Oscar Salvador To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Andrew Morton , Wei Yang , Baoquan He , Pankaj Gupta Subject: Re: [PATCH v2 02/10] mm/memory_hotplug: enforce section granularity when onlining/offlining Message-ID: <20200824103917.GB6315@linux> References: <20200819175957.28465-1-david@redhat.com> <20200819175957.28465-3-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200819175957.28465-3-david@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 19, 2020 at 07:59:49PM +0200, David Hildenbrand wrote: > Already two people (including me) tried to offline subsections, because > the function looks like it can deal with it. But we really can only > online/offline full sections that are properly aligned (e.g., we can only > mark full sections online/offline via SECTION_IS_ONLINE). > > Add a simple safety net to document the restriction now. Current users > (core and powernv/memtrace) respect these restrictions. It's been a while since I looked at sub-section handling stuff so sorry to ask this, but was it true that we can hot-{remove,add} sub-section granularity, while we can only online /offline on section granularity? > > Acked-by: Michal Hocko > Cc: Andrew Morton > Cc: Michal Hocko > Cc: Wei Yang > Cc: Baoquan He > Cc: Pankaj Gupta > Cc: Oscar Salvador > Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE L3