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 449E5C433DB for ; Wed, 20 Jan 2021 11:58:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AA975221F8 for ; Wed, 20 Jan 2021 11:58:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA975221F8 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 AF3756B0005; Wed, 20 Jan 2021 06:58:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AA2596B0006; Wed, 20 Jan 2021 06:58:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 943C66B0007; Wed, 20 Jan 2021 06:58:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id 7B49D6B0005 for ; Wed, 20 Jan 2021 06:58:19 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 432B5180AD81F for ; Wed, 20 Jan 2021 11:58:19 +0000 (UTC) X-FDA: 77726005518.27.feast18_230474c2755a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 286753D663 for ; Wed, 20 Jan 2021 11:58:19 +0000 (UTC) X-HE-Tag: feast18_230474c2755a X-Filterd-Recvd-Size: 3393 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Wed, 20 Jan 2021 11:58:18 +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 7B1E1AAAE; Wed, 20 Jan 2021 11:58:17 +0000 (UTC) Date: Wed, 20 Jan 2021 12:58:14 +0100 From: Oscar Salvador To: David Hildenbrand Cc: Anshuman Khandual , linux-mm@kvack.org, akpm@linux-foundation.org, hca@linux.ibm.com, catalin.marinas@arm.com, Vasily Gorbik , Will Deacon , Ard Biesheuvel , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 1/3] mm/memory_hotplug: Prevalidate the address range being added with platform Message-ID: <20210120115814.GA7107@localhost.localdomain> References: <1610975582-12646-1-git-send-email-anshuman.khandual@arm.com> <1610975582-12646-2-git-send-email-anshuman.khandual@arm.com> <691872bb-b251-83e0-126e-afd54683c83e@redhat.com> <3d4f3b14-0715-b2b3-b015-04b8a77abfb8@arm.com> <30bbf862-06a4-bd1d-b902-61aa4183b819@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <30bbf862-06a4-bd1d-b902-61aa4183b819@redhat.com> 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 Wed, Jan 20, 2021 at 11:41:53AM +0100, David Hildenbrand wrote: > On 20.01.21 09:33, Anshuman Khandual wrote: > > > > > > On 1/19/21 5:51 PM, David Hildenbrand wrote: > >> On 18.01.21 14:12, Anshuman Khandual wrote: > >>> This introduces memhp_range_allowed() which can be called in various memory > >>> hotplug paths to prevalidate the address range which is being added, with > >>> the platform. Then memhp_range_allowed() calls memhp_get_pluggable_range() > >>> which provides applicable address range depending on whether linear mapping > >>> is required or not. For ranges that require linear mapping, it calls a new > >>> arch callback arch_get_mappable_range() which the platform can override. So > >>> the new callback, in turn provides the platform an opportunity to configure > >>> acceptable memory hotplug address ranges in case there are constraints. > >>> > >>> This mechanism will help prevent platform specific errors deep down during > >>> hotplug calls. This drops now redundant check_hotplug_memory_addressable() > >>> check in __add_pages() but instead adds a VM_BUG_ON() check which would > >> > >> In this patch, you keep the __add_pages() checks. But as discussed, we > >> could perform it in mm/memremap.c:pagemap_range() insted and convert it > >> to a VM_BUG_ON(). > > > > Just to be sure, will the following change achieve what you are > > suggesting here. pagemap_range() after this change, will again > > be the same like the V1 series. > > Yeah, as we used to have in v1. Maybe other reviewers (@Oscar?) have a > different opinion. No, I think that placing the check in pagemap_range() out of the if-else makes much more sense. Actually, unless my memory fails me that is what I suggested in v2. I plan to have a look at the series later this week as I am fairly busy atm. Thanks -- Oscar Salvador SUSE L3