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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 9B6F2C43459 for ; Thu, 25 Mar 2021 16:48:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75B8861A2F for ; Thu, 25 Mar 2021 16:48:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230062AbhCYQsG (ORCPT ); Thu, 25 Mar 2021 12:48:06 -0400 Received: from mx2.suse.de ([195.135.220.15]:47302 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229833AbhCYQri (ORCPT ); Thu, 25 Mar 2021 12:47:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1616690857; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wUJU1ZyQiULOm2uGJekEhkNryIBe6sBb+u3KEnxtjyw=; b=ixR9H4iP2iyMq+Ghj46uhoTg/mK9jfek7tT7cuk/lK9zT/cE5RnNCHVi3EVfKiHw6ShxZG /9HAKYeF56YpVnE/MF+0ZhH1ulfaWsuR4VXIT8oaS9CzZMWhfulU4d39gakKEWL5i6DSle LklhJ9PmjCZJ9lajmaRFRY1VdOjb+kY= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DAE63AA55; Thu, 25 Mar 2021 16:47:36 +0000 (UTC) Date: Thu, 25 Mar 2021 17:47:30 +0100 From: Michal Hocko To: David Hildenbrand Cc: Oscar Salvador , Andrew Morton , Anshuman Khandual , Vlastimil Babka , Pavel Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/5] mm,memory_hotplug: Allocate memmap from the added memory range Message-ID: References: <062bc5d7-a83c-1c1a-7b77-9f043643f4fa@redhat.com> <31c3e6f7-f631-7b00-2c33-518b0f24a75f@redhat.com> <40fac999-2d28-9205-23f0-516fa9342bbe@redhat.com> <92fe19d0-56ac-e929-a9c1-d6a4e0da39d1@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 25-03-21 17:36:22, Michal Hocko wrote: > If all it takes is to make pfn_to_online_page work (and my > previous attempt is incorrect because it should consult block rather > than section pfn range) This should work. diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 9697acfe96eb..e50d685be8ab 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -510,6 +510,23 @@ static struct memory_block *find_memory_block_by_id(unsigned long block_id) return mem; } +struct page *is_vmemmap_page(unsigned long pfn) +{ + unsigned long nr = pfn_to_section_nr(pfn); + struct memory_block *mem; + unsigned long block_pfn; + + mem = find_memory_block_by_id(memory_block_id(nr)); + if (!mem || !mem->nr_vmemmap_pages) + return NULL; + + block_pfn = section_nr_to_pfn(mem->start_section_nr); + if (pfn - block_pfn > mem->nr_vmemmap_pages) + return NULL; + + return pfn_to_page(pfn); +} + /* * Called under device_hotplug_lock. */ diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 754026a9164d..760bf3ad48d5 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -304,8 +304,16 @@ struct page *pfn_to_online_page(unsigned long pfn) return NULL; ms = __nr_to_section(nr); - if (!online_section(ms)) + if (!online_section(ms)) { + /* + * vmemmap reserved space can eat up a whole section which then + * never gets onlined because it doesn't contain any memory to + * online. + */ + if (memmap_on_memory) + return is_vmemmap_page(pfn); return NULL; + } /* * Save some code text when online_section() + -- Michal Hocko SUSE Labs