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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 83087C433DB for ; Fri, 26 Feb 2021 06:42:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F320464EE2 for ; Fri, 26 Feb 2021 06:42:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F320464EE2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 280D06B0005; Fri, 26 Feb 2021 01:42:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 22EBF6B0006; Fri, 26 Feb 2021 01:42:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 145F76B006C; Fri, 26 Feb 2021 01:42:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0107.hostedemail.com [216.40.44.107]) by kanga.kvack.org (Postfix) with ESMTP id F23706B0005 for ; Fri, 26 Feb 2021 01:42:40 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id A9E781839E10C for ; Fri, 26 Feb 2021 06:42:40 +0000 (UTC) X-FDA: 77859475680.16.BE3BFB8 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf11.hostedemail.com (Postfix) with ESMTP id 9636A20001EA for ; Fri, 26 Feb 2021 06:42:29 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 132F160238; Fri, 26 Feb 2021 06:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614321758; bh=hX4Qhz8Qgp1SzWBjSDDYOU56u7r54bsxVnDXREAgGN8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=R25R6XdINokIbzL59wiY4Rkm7fp/nYt523xLNqSO0+TQ5gWmHqqUDlZEpbY5jiNIP YfzetFUC3HabYiPDRO+DwX3HrzfMbqYEB8cqbIelYbyk2KvtGQtLlyY1oZaJjr/cVI KxfBlbqWJS863wM/eXzhvONJqNtWukSRuusF3u8A= Date: Fri, 26 Feb 2021 07:42:36 +0100 From: Greg KH To: Mike Rapoport Cc: Andrew Morton , Andrea Arcangeli , Baoquan He , Borislav Petkov , Chris Wilson , David Hildenbrand , "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 Subject: Re: [PATCH v8 1/1] mm/page_alloc.c: refactor initialization of struct page for holes in memory layout Message-ID: References: <20210225224351.7356-1-rppt@kernel.org> <20210225224351.7356-2-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210225224351.7356-2-rppt@kernel.org> X-Stat-Signature: suo9dezk1f3swix4qmdfxofsjqiq5dsu X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9636A20001EA Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf11; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614321749-440061 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 Fri, Feb 26, 2021 at 12:43:51AM +0200, 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); > > in set_pfnblock_flags_mask() when called with a struct page from a range > other than E820_TYPE_RAM because there are pages in the range of ZONE_DMA32 > but the unset zone link in struct page makes them appear as a part of > ZONE_DMA. > > 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. The holes between nodes will be prepended > to the zone/node above the hole and the trailing pages in the last section > that will be appended to the zone/node below. > > Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that check each PFN") > Signed-off-by: Mike Rapoport > Reported-by: Qian Cai > Reported-by: Andrea Arcangeli > Reviewed-by: Baoquan He > Acked-by: Vlastimil Babka > --- > mm/page_alloc.c | 158 +++++++++++++++++++++++------------------------- > 1 file changed, 75 insertions(+), 83 deletions(-) This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.