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 42332C432C1 for ; Tue, 24 Sep 2019 11:45:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04E14214DA for ; Tue, 24 Sep 2019 11:45:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569325512; bh=nXOZ34zlCRJ8DltROMWOWKTuE1F8Q0RKzz9r8H8dQb8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=14dRG/M99kZKKCSXbhby7W8MM9rpo6E7jJqh+0jXaRlgVIizwH5UcmO+SzI/WuuQE EC+N1Wf6JtweqkswCXfST5xAnbt53h96FB/wfe47q2/X0AmNufebyALK2rLJO8VhsH fwtLp9B5s/EYU0iTW3l3G+Ht9DuudQzJex0saV9I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504794AbfIXLpL (ORCPT ); Tue, 24 Sep 2019 07:45:11 -0400 Received: from mx2.suse.de ([195.135.220.15]:60158 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2504767AbfIXLpK (ORCPT ); Tue, 24 Sep 2019 07:45:10 -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 B0DBEB033; Tue, 24 Sep 2019 11:45:04 +0000 (UTC) Date: Tue, 24 Sep 2019 13:45:03 +0200 From: Michal Hocko To: David Hildenbrand Cc: Alastair D'Silva , Andrew Morton , Oscar Salvador , Pavel Tatashin , Dan Williams , Wei Yang , Qian Cai , Jason Gunthorpe , Logan Gunthorpe , Ira Weiny , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/2] memory_hotplug: Add a bounds check to check_hotplug_memory_range() Message-ID: <20190924114503.GK23050@dhcp22.suse.cz> References: <20190917010752.28395-1-alastair@au1.ibm.com> <20190917010752.28395-2-alastair@au1.ibm.com> <20190923122513.GO6016@dhcp22.suse.cz> <25e0af4cb24a41466032d704b89d25559e7ad968.camel@d-silva.org> <20190924090934.GF23050@dhcp22.suse.cz> <32531671-77dd-7857-f34f-f73ea45f7e22@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <32531671-77dd-7857-f34f-f73ea45f7e22@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 Tue 24-09-19 11:13:31, David Hildenbrand wrote: > On 24.09.19 11:09, Michal Hocko wrote: > > On Tue 24-09-19 11:31:05, Alastair D'Silva wrote: > >> On Mon, 2019-09-23 at 14:25 +0200, Michal Hocko wrote: [...] > >>> This will result in a silent failure (unlike misaligned case). Is > >>> this > >>> what we want? > >> > >> Good point - I guess it comes down to, is there anything we expect an > >> end user to do about it? I'm not sure there is, in which case the bad > >> RC, which is reported up every call chain that I can see, should be > >> sufficient. > > > > It seems like a clear HW/platform bug to me. And that should better be > > reported loudly to the log to make sure people do complain to their FW > > friends and have it fixed. > > > > I don't agree in virtual environment. On s390x, MAX_PHYSMEM_BITS is > configurable. For example, if you have paravirtualized memory hotplug > (e.g., virtio-mem), you could add memory to the system that violates > this constraint. What happens if that is the case. Does the machine change the configuration in runtime or it needs a reboot? Anyway, seeing this to be the case in the log would help in whatever action is necessary to deal with the issue, right? -- Michal Hocko SUSE Labs