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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 A2107C7618B for ; Fri, 26 Jul 2019 08:44:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 725B82166E for ; Fri, 26 Jul 2019 08:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564130651; bh=YhISmhfLwfVFIPeWh2qFHPe2omgNrVMCeuEpRODXV3M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Otz1K/PcE1r3n5QzjlU56PlKUolIVGG46ss9YOyB/4nwSu3ll9bUOiS2toqihjSri KjWX6mMjXwfbwzrrPVBxNmR6EJ9egFIFbqLOoPWZcMZ+873xbmRFHqG21NtKffc0XR voni+MupGrKwJE2dkH9WFR6T4XuETdAY+qddlA/Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726007AbfGZIoK (ORCPT ); Fri, 26 Jul 2019 04:44:10 -0400 Received: from mx2.suse.de ([195.135.220.15]:45864 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725944AbfGZIoK (ORCPT ); Fri, 26 Jul 2019 04:44:10 -0400 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 40DBAAD5E; Fri, 26 Jul 2019 08:44:09 +0000 (UTC) Date: Fri, 26 Jul 2019 10:44:08 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, "Rafael J. Wysocki" , Andrew Morton , Oscar Salvador Subject: Re: [PATCH v1] ACPI / scan: Acquire device_hotplug_lock in acpi_scan_init() Message-ID: <20190726084408.GK6142@dhcp22.suse.cz> References: <20190725125636.GA3582@dhcp22.suse.cz> <6dc566c2-faf6-565d-4ef1-2ac3a366bc76@redhat.com> <20190725135747.GB3582@dhcp22.suse.cz> <447b74ca-f7c7-0835-fd50-a9f7191fe47c@redhat.com> <20190725191943.GA6142@dhcp22.suse.cz> <20190726075729.GG6142@dhcp22.suse.cz> <20190726083117.GJ6142@dhcp22.suse.cz> <38d76051-504e-c81a-293a-0b0839e829d3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <38d76051-504e-c81a-293a-0b0839e829d3@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Fri 26-07-19 10:36:42, David Hildenbrand wrote: > On 26.07.19 10:31, Michal Hocko wrote: [...] > > Anyway, my dislike of the device_hotplug_lock persists. I would really > > love to see it go rather than grow even more to the hotplug code. We > > should be really striving for mem hotplug internal and ideally range > > defined locking longterm. > > Yes, and that is a different story, because it will require major > changes to all add_memory() users. (esp, due to the documented race > conditions). Having that said, memory hotplug locking is not ideal yet. I am really happy to hear that we are on the same page here. Do we have any document (I am sorry but I am lacking behind recent development in this area) that describes roadblocks to remove device_hotplug_lock? -- Michal Hocko SUSE Labs