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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 066C6C432C3 for ; Thu, 28 Nov 2019 14:13:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 91464217BC for ; Thu, 28 Nov 2019 14:13:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hpuWfwCw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91464217BC 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 0E5C06B0537; Thu, 28 Nov 2019 09:13:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 098626B0538; Thu, 28 Nov 2019 09:13:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC8D16B0539; Thu, 28 Nov 2019 09:13:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0183.hostedemail.com [216.40.44.183]) by kanga.kvack.org (Postfix) with ESMTP id D237A6B0537 for ; Thu, 28 Nov 2019 09:13:18 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 97CCD2C89 for ; Thu, 28 Nov 2019 14:13:18 +0000 (UTC) X-FDA: 76205878476.04.room14_39c601129ca58 X-HE-Tag: room14_39c601129ca58 X-Filterd-Recvd-Size: 9660 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-2.mimecast.com [205.139.110.61]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Thu, 28 Nov 2019 14:13:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574950396; 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:autocrypt:autocrypt; bh=Ve7szSjvJh3kgquZxWaubs6vKIh8plfJL95O1zxuWm4=; b=hpuWfwCwUDRcWe5sqMtkQmcziE9D545Rcy/jNC5Jh8DifOTcwNoj+N7yC5ye6eWrdgmhFj Ytfxq+AST/mXoaBB/PVh1NXkqoHKcsV2EAJwpBHsA0DPqtkde9DTJMeSF4z58Nhx8zjasG hL7zcFtdeF0u8CpsDu7k6Ql1TXQc6qk= 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-330-pO5zVa9iNUOjll4krIJdEA-1; Thu, 28 Nov 2019 09:13:10 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E84BB593AF; Thu, 28 Nov 2019 14:13:08 +0000 (UTC) Received: from [10.36.118.27] (unknown [10.36.118.27]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A68B1000337; Thu, 28 Nov 2019 14:13:07 +0000 (UTC) Subject: Re: [PATCH v1] drivers/base/node.c: get rid of get_nid_for_pfn() From: David Hildenbrand To: Michal Hocko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Oscar Salvador , Andrew Morton References: <20191128102051.GI26807@dhcp22.suse.cz> <5E2F5866-0605-4DD2-9AEA-4B1C44E57D9F@redhat.com> <20191128115021.GJ26807@dhcp22.suse.cz> <20191128120121.GL26807@dhcp22.suse.cz> <17785662-d004-21ad-16a6-296c82779c8f@redhat.com> Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAj4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+uQINBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABiQIl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <3f597f0d-a0d0-4bff-28cc-3fa92aa0b70f@redhat.com> Date: Thu, 28 Nov 2019 15:13:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <17785662-d004-21ad-16a6-296c82779c8f@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: pO5zVa9iNUOjll4krIJdEA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable 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 28.11.19 13:19, David Hildenbrand wrote: > On 28.11.19 13:01, Michal Hocko wrote: >> On Thu 28-11-19 12:52:16, David Hildenbrand wrote: >>> On 28.11.19 12:50, Michal Hocko wrote: >>>> On Thu 28-11-19 12:23:08, David Hildenbrand wrote: >>>> [...] >>>>> >From fc13fd540a1702592e389e821f6266098e41e2bd Mon Sep 17 00:00:00 20= 01 >>>>> From: David Hildenbrand >>>>> Date: Wed, 27 Nov 2019 16:18:42 +0100 >>>>> Subject: [PATCH] drivers/base/node.c: optimize get_nid_for_pfn() >>>>> >>>>> Since commit d84f2f5a7552 ("drivers/base/node.c: simplify >>>>> unregister_memory_block_under_nodes()") we only have a single user of >>>>> get_nid_for_pfn(). The remaining user calls this function when bootin= g - >>>>> where all added memory is online. >>>>> >>>>> Make it clearer that this function should only be used during boot ( >>>>> e.g., calling it on offline memory would be bad) by renaming the >>>>> function to something meaningful, optimize out the ifdef and the addi= tional >>>>> system_state check, and add a comment why CONFIG_DEFERRED_STRUCT_PAGE= _INIT >>>>> handling is in place at all. >>>>> >>>>> Also, optimize the call site. There is no need to check against >>>>> page_nid < 0 - it will never match the nid (nid >=3D 0). >>>>> >>>>> Cc: Greg Kroah-Hartman >>>>> Cc: "Rafael J. Wysocki" >>>>> Cc: Michal Hocko >>>>> Cc: Oscar Salvador >>>>> Cc: Andrew Morton >>>>> Signed-off-by: David Hildenbrand >>>> >>>> Yes this looks much better! I am not sure this will pass all weird >>>> config combinations because IS_ENABLED will not hide early_pfn_to_nid >>>> from the early compiler stages so it might complain. But if this passe= s >>>> 0day compile scrutiny then this is much much better. If not then we ju= st >>>> have to use ifdef which is a minor thing. >>> >>> The compiler should optimize out >>> >>> if (0) >>> =09code >>> >>> and therefore never link to early_pfn_to_nid. >> >> You are right, but there is a catch. The optimization phase is much >> later than the syntactic check so if the code doesn't make sense >> for the syntactic point of view then it will complain. This is a notable >> difference to #ifdef which just removes the whole block in the >> preprocessor phase. >> >=20 > We should always have a declaration of early_pfn_to_nid(). The > interesting part AFAIKS is include/linux/mmzone.h: >=20 > #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ > =09!defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) > static inline unsigned long early_pfn_to_nid(unsigned long pfn) > { > =09BUILD_BUG_ON(IS_ENABLED(CONFIG_NUMA)); > =09return 0; > } > #endif >=20 > so we would have >=20 > if (IS_ENABLED(...)) > =09BUILD_BUG_ON(IS_ENABLED(CONFIG_NUMA)); >=20 > Let's see how that will turn out :) Will do some test builds > (CONFIG_NUMA, !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID and > !CONFIG_HAVE_MEMBLOCK_NODE_MAP) ... if possible >=20 So ... the code is fenced by MEMORY_HOTPLUG_SPARSE, which requires "SPARSEMEM && MEMORY_HOTPLUG". MEMORY_HOTPLUG requires ARCH_ENABLE_MEMORY_HOTPLUG Architectures with ARCH_ENABLE_MEMORY_HOTPLUG (conditional): arm64, ia64, powerpc, s390, sh, x86 Architectures with HAVE_MEMBLOCK_NODE_MAP (unconditional): arm64, ia64, mips, powerpc, riscv, s390, sh, sparc, x86 Which implies that we will always have mm/page_alloc.c:early_pfn_to_nid() and therefore no compile issues with if (IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) =09return early_pfn_to_nid(pfn); Will do more testing and send this as an official patch. Thanks! --=20 Thanks, David / dhildenb