From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id 611986B000A for ; Thu, 4 Oct 2018 11:28:15 -0400 (EDT) Received: by mail-ed1-f71.google.com with SMTP id g36-v6so5798122edb.3 for ; Thu, 04 Oct 2018 08:28:15 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 23-v6si475892ejr.103.2018.10.04.08.28.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Oct 2018 08:28:13 -0700 (PDT) Date: Thu, 4 Oct 2018 17:28:07 +0200 From: Michal =?UTF-8?B?U3VjaMOhbmVr?= Subject: Re: [PATCH RFC] mm/memory_hotplug: Introduce memory block types Message-ID: <20181004172807.1eef3a6b@kitsune.suse.cz> In-Reply-To: References: <20181001084038.GD18290@dhcp22.suse.cz> <20181002134734.GT18290@dhcp22.suse.cz> <98fb8d65-b641-2225-f842-8804c6f79a06@redhat.com> <8736tndubn.fsf@vitty.brq.redhat.com> <20181003134444.GH4714@dhcp22.suse.cz> <87zhvvcf3b.fsf@vitty.brq.redhat.com> <49456818-238e-2d95-9df6-d1934e9c8b53@linux.intel.com> <87tvm3cd5w.fsf@vitty.brq.redhat.com> <06a35970-e478-18f8-eae6-4022925a5192@redhat.com> <20181004061938.GB22173@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Hildenbrand Cc: Michal Hocko , Kate Stewart , Rich Felker , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Dave Hansen , Heiko Carstens , linux-mm@kvack.org, Paul Mackerras , "H. Peter Anvin" , Stephen Rothwell , Rashmica Gupta , Dan Williams , linux-s390@vger.kernel.org, Michael Neuling , Stephen Hemminger , Yoshinori Sato , linux-acpi@vger.kernel.org, Ingo Molnar , xen-devel@lists.xenproject.org, Len Brown , Pavel Tatashin , Rob Herring , "mike.travis@hpe.com" , Haiyang Zhang , Jonathan =?UTF-8?B?TmV1c2Now6Rm?= =?UTF-8?B?ZXI=?= , Nicholas Piggin , Martin Schwidefsky , =?UTF-8?B?SsOpcsO0bWU=?= Glisse , Mike Rapoport , Borislav Petkov , Andy Lutomirski , Boris Ostrovsky , Joonsoo Kim , Oscar Salvador , Juergen Gross , Tony Luck , Andrew Morton , Mathieu Malaterre , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Fenghua Yu , Mauricio Faria de Oliveira , Thomas Gleixner , Philippe Ombredanne , Joe Perches , devel@linuxdriverproject.org, Vitaly Kuznetsov , linuxppc-dev@lists.ozlabs.org, "Kirill A. Shutemov" On Thu, 4 Oct 2018 10:13:48 +0200 David Hildenbrand wrote: ok, so what is the problem here? Handling the hotplug in userspace through udev may be suboptimal and kernel handling might be faster but that's orthogonal to the problem at hand. The state of the art is to determine what to do with hotplugged memory in userspace based on platform and virtualization type. Changing the default to depend on the driver that added the memory rather than platform type should solve the issue of VMs growing different types of memory device emulation. Am I missing something? Thanks Michal