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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 7D937C433DF for ; Wed, 1 Jul 2020 11:31:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3EDEB20760 for ; Wed, 1 Jul 2020 11:31:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZYhZvrvb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3EDEB20760 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 A26C26B00D3; Wed, 1 Jul 2020 07:31:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9D72E6B00D4; Wed, 1 Jul 2020 07:31:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8C68E6B00D5; Wed, 1 Jul 2020 07:31:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id 770646B00D3 for ; Wed, 1 Jul 2020 07:31:06 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 1BDFF2DFD for ; Wed, 1 Jul 2020 11:31:06 +0000 (UTC) X-FDA: 76989290532.06.coal52_2a1757d26e80 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id D3A1D1003A841 for ; Wed, 1 Jul 2020 11:31:05 +0000 (UTC) X-HE-Tag: coal52_2a1757d26e80 X-Filterd-Recvd-Size: 9603 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Wed, 1 Jul 2020 11:31:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593603064; 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=7cAEZ0VUk04rqXCh5EEKOgMEkG2PuKnDXKZqj/gtn1g=; b=ZYhZvrvbKKygILSwrw0sWl9j9fmI83y1Fwogw1DCpapN6/vieG9zmUVOiUGeNhMWipKU1L owSDI9N5YYS9rhVWuIWfMMZXJGt5X7MnosGNujj/P+bG+coGoUpBsk+foeBScO/ThgOx1W Waob5og7ZgxLbfO9hRBHiKQ/5M21sJo= 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-343-wCTosYe2O8Wa42tj-lYTiw-1; Wed, 01 Jul 2020 07:31:02 -0400 X-MC-Unique: wCTosYe2O8Wa42tj-lYTiw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9C71C107ACCA; Wed, 1 Jul 2020 11:31:00 +0000 (UTC) Received: from [10.36.112.52] (ovpn-112-52.ams2.redhat.com [10.36.112.52]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7CDD5C1D0; Wed, 1 Jul 2020 11:30:57 +0000 (UTC) Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline From: David Hildenbrand To: Srikar Dronamraju Cc: Michal Hocko , Andrew Morton , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman , Vlastimil Babka , "Kirill A. Shutemov" , Christopher Lameter , Michael Ellerman , Linus Torvalds , Gautham R Shenoy , Satheesh Rajendran References: <20200624092846.9194-1-srikar@linux.vnet.ibm.com> <20200624092846.9194-4-srikar@linux.vnet.ibm.com> <20200701084200.GN2369@dhcp22.suse.cz> <20200701100442.GB17918@linux.vnet.ibm.com> <184102af-ecf2-c834-db46-173ab2e66f51@redhat.com> <20200701110145.GC17918@linux.vnet.ibm.com> <0468f965-8762-76a3-93de-3987cf859927@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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: <12945273-d788-710d-e8d7-974966529c7d@redhat.com> Date: Wed, 1 Jul 2020 13:30:57 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <0468f965-8762-76a3-93de-3987cf859927@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Rspamd-Queue-Id: D3A1D1003A841 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 01.07.20 13:06, David Hildenbrand wrote: > On 01.07.20 13:01, Srikar Dronamraju wrote: >> * David Hildenbrand [2020-07-01 12:15:54]: >> >>> On 01.07.20 12:04, Srikar Dronamraju wrote: >>>> * Michal Hocko [2020-07-01 10:42:00]: >>>> >>>>> >>>>>> >>>>>> 2. Also existence of dummy node also leads to inconsistent information. The >>>>>> number of online nodes is inconsistent with the information in the >>>>>> device-tree and resource-dump >>>>>> >>>>>> 3. When the dummy node is present, single node non-Numa systems end up showing >>>>>> up as NUMA systems and numa_balancing gets enabled. This will mean we take >>>>>> the hit from the unnecessary numa hinting faults. >>>>> >>>>> I have to say that I dislike the node online/offline state and directly >>>>> exporting that to the userspace. Users should only care whether the node >>>>> has memory/cpus. Numa nodes can be online without any memory. Just >>>>> offline all the present memory blocks but do not physically hot remove >>>>> them and you are in the same situation. If users are confused by an >>>>> output of tools like numactl -H then those could be updated and hide >>>>> nodes without any memory&cpus. >>>>> >>>>> The autonuma problem sounds interesting but again this patch doesn't >>>>> really solve the underlying problem because I strongly suspect that the >>>>> problem is still there when a numa node gets all its memory offline as >>>>> mentioned above. >>>>> >>>>> While I completely agree that making node 0 special is wrong, I have >>>>> still hard time to review this very simply looking patch because all the >>>>> numa initialization is so spread around that this might just blow up >>>>> at unexpected places. IIRC we have discussed testing in the previous >>>>> version and David has provided a way to emulate these configurations >>>>> on x86. Did you manage to use those instruction for additional testing >>>>> on other than ppc architectures? >>>>> >>>> >>>> I have tried all the steps that David mentioned and reported back at >>>> https://lore.kernel.org/lkml/20200511174731.GD1961@linux.vnet.ibm.com/t/#u >>>> >>>> As a summary, David's steps are still not creating a memoryless/cpuless on >>>> x86 VM. >>> >>> Now, that is wrong. You get a memoryless/cpuless node, which is *not >>> online*. Once you hotplug some memory, it will switch online. Once you >>> remove memory, it will switch back offline. >>> >> >> Let me clarify, we are looking for a node 0 which is cpuless/memoryless at >> boot. The code in question tries to handle a cpuless/memoryless node 0 at >> boot. > > I was just correcting your statement, because it was wrong. > > Could be that x86 code maps PXM 1 to node 0 because PXM 1 does neither > have CPUs nor memory. That would imply that we can, in fact, never have > node 0 offline during boot. > Yep, looks like it. [ 0.009726] SRAT: PXM 1 -> APIC 0x00 -> Node 0 [ 0.009727] SRAT: PXM 1 -> APIC 0x01 -> Node 0 [ 0.009727] SRAT: PXM 1 -> APIC 0x02 -> Node 0 [ 0.009728] SRAT: PXM 1 -> APIC 0x03 -> Node 0 [ 0.009731] ACPI: SRAT: Node 0 PXM 1 [mem 0x00000000-0x0009ffff] [ 0.009732] ACPI: SRAT: Node 0 PXM 1 [mem 0x00100000-0xbfffffff] [ 0.009733] ACPI: SRAT: Node 0 PXM 1 [mem 0x100000000-0x13fffffff] -- Thanks, David / dhildenb