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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DCA3DC64E8A for ; Wed, 2 Dec 2020 12:16:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3C0E1221FE for ; Wed, 2 Dec 2020 12:16:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C0E1221FE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 317AE8D0001; Wed, 2 Dec 2020 07:16:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2C7A36B006C; Wed, 2 Dec 2020 07:16:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E0618D0001; Wed, 2 Dec 2020 07:16:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id 0A07B6B0068 for ; Wed, 2 Dec 2020 07:16:00 -0500 (EST) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C4FAD180AD81A for ; Wed, 2 Dec 2020 12:15:59 +0000 (UTC) X-FDA: 77548238838.10.berry35_0606662273b3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin10.hostedemail.com (Postfix) with ESMTP id 910E016A06B for ; Wed, 2 Dec 2020 12:15:59 +0000 (UTC) X-HE-Tag: berry35_0606662273b3 X-Filterd-Recvd-Size: 4398 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Wed, 2 Dec 2020 12:15:59 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 34FC7101E; Wed, 2 Dec 2020 04:15:58 -0800 (PST) Received: from [192.168.0.130] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5E52D3F718; Wed, 2 Dec 2020 04:15:56 -0800 (PST) Subject: Re: [RFC V2 1/3] mm/hotplug: Prevalidate the address range being added with platform To: David Hildenbrand , linux-mm@kvack.org, akpm@linux-foundation.org Cc: linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <1606706992-26656-1-git-send-email-anshuman.khandual@arm.com> <1606706992-26656-2-git-send-email-anshuman.khandual@arm.com> <864c701a-4391-f768-1b95-1992e21835a2@redhat.com> From: Anshuman Khandual Message-ID: <349f7b33-cd5b-4240-e7c0-d8ad39c8ba71@arm.com> Date: Wed, 2 Dec 2020 17:45:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <864c701a-4391-f768-1b95-1992e21835a2@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 12/2/20 2:50 PM, David Hildenbrand wrote: > On 30.11.20 04:29, 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(). >> > > > [...] > >> /* >> * Reasonably generic function for adding memory. It is >> * expected that archs that support memory hotplug will >> @@ -317,10 +304,6 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, >> if (WARN_ON_ONCE(!params->pgprot.pgprot)) >> return -EINVAL; >> >> - err = check_hotplug_memory_addressable(pfn, nr_pages); >> - if (err) >> - return err; >> - > > I was wondering if we should add a VM_BUG_ON(!memhp_range_allowed()) > here to make it clearer that callers are expected to check that first. > Maybe an other places as well (e.g., arch code where we remove the > original checks) Makes sense, will add them. > > [...] > > >> #endif /* CONFIG_MEMORY_HOTREMOVE */ >> diff --git a/mm/memremap.c b/mm/memremap.c >> index 16b2fb482da1..26c1825756cc 100644 >> --- a/mm/memremap.c >> +++ b/mm/memremap.c >> @@ -185,6 +185,7 @@ static void dev_pagemap_percpu_release(struct percpu_ref *ref) >> static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, >> int range_id, int nid) >> { >> + const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE; >> struct range *range = &pgmap->ranges[range_id]; >> struct dev_pagemap *conflict_pgmap; >> int error, is_ram; >> @@ -230,6 +231,9 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, >> if (error) >> goto err_pfn_remap; >> >> + if (!memhp_range_allowed(range->start, range_len(range), !is_private)) >> + goto err_pfn_remap; >> + >> mem_hotplug_begin(); >> >> /* >> @@ -243,7 +247,7 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, >> * the CPU, we do want the linear mapping and thus use >> * arch_add_memory(). >> */ >> - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { >> + if (is_private) { >> error = add_pages(nid, PHYS_PFN(range->start), >> PHYS_PFN(range_len(range)), params); >> } else { >> > > In general, LGTM. > Okay