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 92A8BC56202 for ; Wed, 25 Nov 2020 11:42:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D2DE206D9 for ; Wed, 25 Nov 2020 11:42:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eCAuAmVO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729060AbgKYLmG (ORCPT ); Wed, 25 Nov 2020 06:42:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41504 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728515AbgKYLmF (ORCPT ); Wed, 25 Nov 2020 06:42:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606304524; 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=kcga+3U3k+ggBjhVVfMJediaLV/QYUipju37iPGkLXg=; b=eCAuAmVOS+FlPRhGnNgpX9dTLG81YJPGF80vwQYZT1Z+ZFOW1JY5RZodUk6OWzTCa2Zcxh QKLm/5b18Xowjjf2KvCft4+rafp0pTBw27utLieodlf/2r/9dfBXA7fcOYChaV0dZy2V/e kTBFRDc+e8UYTP1zjYp7q2EgzW7vgnU= 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-499-UaTaFx1OOpiQPcHNG11D1g-1; Wed, 25 Nov 2020 06:42:00 -0500 X-MC-Unique: UaTaFx1OOpiQPcHNG11D1g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9AB0A1E7CE; Wed, 25 Nov 2020 11:41:58 +0000 (UTC) Received: from [10.36.112.131] (ovpn-112-131.ams2.redhat.com [10.36.112.131]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9F415D9C2; Wed, 25 Nov 2020 11:41:56 +0000 (UTC) Subject: Re: [PATCH 1/1] mm: compaction: avoid fast_isolate_around() to set pageblock_skip on reserved pages From: David Hildenbrand To: Mel Gorman Cc: Andrea Arcangeli , Vlastimil Babka , Andrew Morton , linux-mm@kvack.org, Qian Cai , Michal Hocko , linux-kernel@vger.kernel.org, Mike Rapoport , Baoquan He References: <35F8AADA-6CAA-4BD6-A4CF-6F29B3F402A4@redhat.com> <20201125103933.GM3306@suse.de> <5f01bde6-fe31-9b0e-f288-06b82598a8b3@redhat.com> Organization: Red Hat GmbH Message-ID: <33612969-92a1-6c49-a2e0-3a95715b1e7f@redhat.com> Date: Wed, 25 Nov 2020 12:41:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <5f01bde6-fe31-9b0e-f288-06b82598a8b3@redhat.com> Content-Type: text/plain; charset=iso-8859-15 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.11.20 12:04, David Hildenbrand wrote: > On 25.11.20 11:39, Mel Gorman wrote: >> On Wed, Nov 25, 2020 at 07:45:30AM +0100, David Hildenbrand wrote: >>>> Something must have changed more recently than v5.1 that caused the >>>> zoneid of reserved pages to be wrong, a possible candidate for the >>>> real would be this change below: >>>> >>>> + __init_single_page(pfn_to_page(pfn), pfn, 0, 0); >>>> >>> >>> Before that change, the memmap of memory holes were only zeroed out. So the zones/nid was 0, however, pages were not reserved and had a refcount of zero - resulting in other issues. >>> >>> Most pfn walkers shouldn???t mess with reserved pages and simply skip them. That would be the right fix here. >>> >> >> Ordinarily yes, pfn walkers should not care about reserved pages but it's >> still surprising that the node/zone linkages would be wrong for memory >> holes. If they are in the middle of a zone, it means that a hole with >> valid struct pages could be mistaken for overlapping nodes (if the hole >> was in node 1 for example) or overlapping zones which is just broken. > > I agree within zones - but AFAIU, the issue is reserved memory between > zones, right? Double checking, I was confused. This applies also to memory holes within zones in x86. -- Thanks, David / dhildenb