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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3A913C433DB for ; Fri, 26 Mar 2021 08:57:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 67DC2619FC for ; Fri, 26 Mar 2021 08:57:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67DC2619FC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BABAA6B006E; Fri, 26 Mar 2021 04:57:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B82B26B0070; Fri, 26 Mar 2021 04:57:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A4A366B0071; Fri, 26 Mar 2021 04:57:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0156.hostedemail.com [216.40.44.156]) by kanga.kvack.org (Postfix) with ESMTP id 89F1B6B006E for ; Fri, 26 Mar 2021 04:57:48 -0400 (EDT) Received: from smtpin40.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 407991E06 for ; Fri, 26 Mar 2021 08:57:48 +0000 (UTC) X-FDA: 77961422616.40.D94DF1E Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf15.hostedemail.com (Postfix) with ESMTP id 0A074A0000FC for ; Fri, 26 Mar 2021 08:57:45 +0000 (UTC) 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 63FDDAB8A; Fri, 26 Mar 2021 08:57:46 +0000 (UTC) Date: Fri, 26 Mar 2021 09:57:43 +0100 From: Oscar Salvador To: David Hildenbrand Cc: Michal Hocko , Andrew Morton , Anshuman Khandual , Vlastimil Babka , Pavel Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/5] mm,memory_hotplug: Allocate memmap from the added memory range Message-ID: References: <40fac999-2d28-9205-23f0-516fa9342bbe@redhat.com> <92fe19d0-56ac-e929-a9c1-d6a4e0da39d1@redhat.com> <5be95091-b4ac-8e05-4694-ac5c65f790a4@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5be95091-b4ac-8e05-4694-ac5c65f790a4@redhat.com> X-Stat-Signature: t8cn8amuzg78t8g7cepdtbquj81h47as X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0A074A0000FC Received-SPF: none (suse.de>: No applicable sender policy available) receiver=imf15; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1616749065-310811 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 Fri, Mar 26, 2021 at 09:52:58AM +0100, David Hildenbrand wrote: > Might have to set fully spanned section online. (vmemmap >= SECTION_SIZE) Hi David, could you elaborate on this a bit? > Something else to note: > > > We'll not call the memory notifier (e.g., MEM_ONLINE) for the vmemmap. The > result is that > > 1. We won't allocate extended struct pages for the range. Don't think this > is really problematic (pages are never allocated/freed, so I guess we don't > care - like ZONE_DEVICE code). > > 2. We won't allocate kasan shadow memory. We most probably have to do it > explicitly via kasan_add_zero_shadow()/kasan_remove_zero_shadow(), see > mm/memremap.c:pagemap_range() > > > Further a locking rework might be necessary. We hold the device hotplug > lock, but not the memory hotplug lock. E.g., for get_online_mems(). Might > have to move that out online_pages. I will have a look and see how it goes. -- Oscar Salvador SUSE L3