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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, 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 10990C3A5A6 for ; Mon, 23 Sep 2019 12:30:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D4A71207FD for ; Mon, 23 Sep 2019 12:30:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4A71207FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 807D06B000A; Mon, 23 Sep 2019 08:30:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 791416B000C; Mon, 23 Sep 2019 08:30:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6A5CB6B000D; Mon, 23 Sep 2019 08:30:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id 437686B000A for ; Mon, 23 Sep 2019 08:30:11 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id E5173AF80 for ; Mon, 23 Sep 2019 12:30:10 +0000 (UTC) X-FDA: 75966117780.26.bite97_75f1e83550135 X-HE-Tag: bite97_75f1e83550135 X-Filterd-Recvd-Size: 2923 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Mon, 23 Sep 2019 12:30:10 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 316D9AF16; Mon, 23 Sep 2019 12:30:09 +0000 (UTC) Date: Mon, 23 Sep 2019 14:30:08 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Souptick Joarder , linux-hyperv@vger.kernel.org, Andrew Morton , Dan Williams , Haiyang Zhang , "K. Y. Srinivasan" , Oscar Salvador , Pavel Tatashin , Qian Cai , Sasha Levin , Stephen Hemminger , Wei Yang Subject: Re: [PATCH v1 0/3] mm/memory_hotplug: Export generic_online_page() Message-ID: <20190923123008.GP6016@dhcp22.suse.cz> References: <20190909114830.662-1-david@redhat.com> <20190923085807.GD6016@dhcp22.suse.cz> <20190923111559.GK6016@dhcp22.suse.cz> <88ac3511-4ad8-d5c8-8e6a-0cca0a0f0989@redhat.com> <20190923120719.GM6016@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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: On Mon 23-09-19 14:20:05, David Hildenbrand wrote: > On 23.09.19 14:07, Michal Hocko wrote: > > On Mon 23-09-19 13:34:18, David Hildenbrand wrote: > >> On 23.09.19 13:15, Michal Hocko wrote: > > [...] > >>> I am wondering why those pages get onlined when they are, in fact, > >>> supposed to be offline. > >>> > >> > >> It's the current way of emulating sub-memory-block hotplug on top of the > >> memory bock device API we have. Hyper-V and XEN have been using that for > >> a long time. > > > > Do they really have to use the existing block interface when they in > > fact do not operate on the block granularity? Zone device memory already > > acts on sub section/block boundaries. > > > > Yes, we need memory blocks, especially for user space to properly online > them (as we discussed a while back, to decide on a zone) and for udev > events, to e.g., properly reload kexec when memory blocks get > added/removed/onlined/offlined. Just to make sure I really follow. We need a user interface to control where the memory gets onlined but it is the driver which determines which part of the block really gets onlined, right? -- Michal Hocko SUSE Labs