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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 7D39AC433E0 for ; Tue, 23 Feb 2021 08:04:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EBC3464DE7 for ; Tue, 23 Feb 2021 08:04:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBC3464DE7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 49A5D6B006E; Tue, 23 Feb 2021 03:04:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 44B2B6B0070; Tue, 23 Feb 2021 03:04:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 339676B0071; Tue, 23 Feb 2021 03:04:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0168.hostedemail.com [216.40.44.168]) by kanga.kvack.org (Postfix) with ESMTP id 1BAD66B006E for ; Tue, 23 Feb 2021 03:04:51 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D7BC28248047 for ; Tue, 23 Feb 2021 08:04:50 +0000 (UTC) X-FDA: 77848796340.12.6534B87 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf27.hostedemail.com (Postfix) with ESMTP id 80BEC80192D5 for ; Tue, 23 Feb 2021 08:04:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614067489; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TvIJWNY4/1GkazmbPNAwia/J/m5uVDdO8zNLf6UfHyc=; b=PghX9CnoOxvbWUo4w9lr4hKJrzriHfT8Bks71Zf8rMRRJoBc8i05xpHpoAPMuRuPy+8lE5 zvNI2VUfp1hps+SdYq2TItPGIw5NOl28MPIO4/Jcb2hn2y5nQDa349e1GGKW9HURZ7OEwt 7/pH/JryIBjClET/6O67FhsDXeaeahk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-415-RMz4k9mhMuqSZi37eipL3A-1; Tue, 23 Feb 2021 03:04:45 -0500 X-MC-Unique: RMz4k9mhMuqSZi37eipL3A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AA3B780197A; Tue, 23 Feb 2021 08:04:27 +0000 (UTC) Received: from [10.36.114.0] (ovpn-114-0.ams2.redhat.com [10.36.114.0]) by smtp.corp.redhat.com (Postfix) with ESMTP id ABF4719725; Tue, 23 Feb 2021 08:04:20 +0000 (UTC) Subject: Re: [PATCH v6 1/1] mm/page_alloc.c: refactor initialization of struct page for holes in memory layout To: Mike Rapoport , Andrew Morton Cc: Andrea Arcangeli , Baoquan He , Borislav Petkov , Chris Wilson , "H. Peter Anvin" , Ingo Molnar , Linus Torvalds , =?UTF-8?Q?=c5=81ukasz_Majczak?= , Mel Gorman , Michal Hocko , Mike Rapoport , Qian Cai , "Sarvela, Tomi P" , Thomas Gleixner , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, x86@kernel.org References: <20210222105728.28636-1-rppt@kernel.org> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Tue, 23 Feb 2021 09:04:19 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210222105728.28636-1-rppt@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 80BEC80192D5 X-Stat-Signature: 55n5eqancndb8ywyca1f6awms5qxkqow Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf27; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614067484-783822 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 22.02.21 11:57, Mike Rapoport wrote: > From: Mike Rapoport > > There could be struct pages that are not backed by actual physical memory. > This can happen when the actual memory bank is not a multiple of > SECTION_SIZE or when an architecture does not register memory holes > reserved by the firmware as memblock.memory. > > Such pages are currently initialized using init_unavailable_mem() function > that iterates through PFNs in holes in memblock.memory and if there is a > struct page corresponding to a PFN, the fields of this page are set to > default values and it is marked as Reserved. > > init_unavailable_mem() does not take into account zone and node the page > belongs to and sets both zone and node links in struct page to zero. > > Before commit 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions > rather that check each PFN") the holes inside a zone were re-initialized > during memmap_init() and got their zone/node links right. However, after > that commit nothing updates the struct pages representing such holes. > > On a system that has firmware reserved holes in a zone above ZONE_DMA, for > instance in a configuration below: > > # grep -A1 E820 /proc/iomem > 7a17b000-7a216fff : Unknown E820 type > 7a217000-7bffffff : System RAM > > unset zone link in struct page will trigger > > VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); > > because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link > in struct page) in the same pageblock. > > Interleave initialization of the unavailable pages with the normal > initialization of memory map, so that zone and node information will be > properly set on struct pages that are not backed by the actual memory. > > With this change the pages for holes inside a zone will get proper > zone/node links and the pages that are not spanned by any node will get > links to the adjacent zone/node. Does this include pages in the last section has handled by ... ... > - /* > - * Early sections always have a fully populated memmap for the whole > - * section - see pfn_valid(). If the last section has holes at the > - * end and that section is marked "online", the memmap will be > - * considered initialized. Make sure that memmap has a well defined > - * state. > - */ > - pgcnt += init_unavailable_range(PFN_DOWN(next), > - round_up(max_pfn, PAGES_PER_SECTION)); > - ^ this code? Or how is that case handled now? -- Thanks, David / dhildenb