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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 034E2C71155 for ; Mon, 16 Jun 2025 14:26:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 961A66B00BC; Mon, 16 Jun 2025 10:26:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 912276B00BD; Mon, 16 Jun 2025 10:26:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7DA746B00BE; Mon, 16 Jun 2025 10:26:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 6B4826B00BC for ; Mon, 16 Jun 2025 10:26:48 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 575CE160502 for ; Mon, 16 Jun 2025 14:26:47 +0000 (UTC) X-FDA: 83561490054.16.2665C3D Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id D1A9B140004 for ; Mon, 16 Jun 2025 14:26:44 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="E/zVWsF0"; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1750084005; h=from:from:sender: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:dkim-signature; bh=1fgPDBu0KJ43+rGAV2urrNF2orX2coVnVUvF2z+7Yq8=; b=jJzeNYDa7Q5OXxA+vTaYyX1KJ9+MKUeEtdbDnEZofwDrGvEVeYs+Z9u9XMVg6g0/9H5RIq YpNlmTtBVQtbZ9cJ7MVmfUtMiCBds8f91Sp1pgijOkhl04ogUqQZlpbR74nXJZM4DMrpap 9TA7E5A9Bp+hX2otrHep1XYk/B82SF8= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="E/zVWsF0"; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750084005; a=rsa-sha256; cv=none; b=3jirYY3GqElVvDr+ZVo3vOaOPSZi5eeKzFNShtPCPxzJksHC8XWbEiiIQfdwph6KxGeSp7 o2lBeJV+2rBs55qw5fY15NIbybzFSSev0oI++Z1iKzUkoJS21e9xUPXB1ViUZarbQQxViz GudxeezRZWSGGRpLrhRw7NOJLQ+FWGs= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750084004; 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=1fgPDBu0KJ43+rGAV2urrNF2orX2coVnVUvF2z+7Yq8=; b=E/zVWsF0QrABHsLOzOMTp48WVNOaXkqgSoHarnJ9yBx0h/1c+uMgJX8BX82NC58U7PvWnB RpBuFriI+SFAfn+Hi8C52Vz9bfF2ZjEaQFAipSLt62OQ+eG4p1jsVXvadugKei9uU2q5U6 ZwzYBPk/2khEOFvrtKTVFO7MhX3uaI4= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-673-P2SiHxz2PDGTL7PGRhZ2kA-1; Mon, 16 Jun 2025 10:26:40 -0400 X-MC-Unique: P2SiHxz2PDGTL7PGRhZ2kA-1 X-Mimecast-MFC-AGG-ID: P2SiHxz2PDGTL7PGRhZ2kA_1750084000 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3a50816ccc6so2578537f8f.1 for ; Mon, 16 Jun 2025 07:26:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750083999; x=1750688799; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=1fgPDBu0KJ43+rGAV2urrNF2orX2coVnVUvF2z+7Yq8=; b=fsSBP0iFoTqA1cfGxPrFSosPByz7ZJm6eXMxhWkOLFKMEHq659AJtHPHo88p9M4dfH 3vEUeVJrAm+AE9R6j7cP/yZN0FZMIVw4rbaC2QX4C1mSAtPgfjdng01YcikGrhARRcD/ VVrK1TnD3WgdbLYaB3vFnHCIu4lle8fpBAJK6mdCgBI1L4yzo8wcRDxjmhKD+olVQ3mz oTblIkqqbb3Hv4yI9nF1Fh/fmzCPhzv9wcYYGIKWJJmEy93kMtcShhHoV2nQXRnIMy61 LekZyJfIsgsrx/6k32Q2f14PkZ47zMR7J03x7ZBgExviAPdO1LZt4MqYNwOcjWdzlKBQ BTvA== X-Gm-Message-State: AOJu0Yy+DO03/LxGEc4mh2dQnKVp5nt6/QiU3xp804fFkyBoMAbNjtjw wlru1lZe3R3itGpdJsM0bbAk1vAKlzyRb96Ksdhm0GaJwjPRZKaEBLdlG5CgHyxnDgedh0i4iWr 1KsKdWRjRIZl+YYv9R3to2/chygv28qRo4OlL4p8m/rWsegjfk+7b X-Gm-Gg: ASbGncvVfufcxItg6kQZ3XQPoYf9lyaH2D75XiZLaVYPRc64rTamkrJICvLIOqBHZ0P tkRnqqkgvGejX9PozQFliXPd44e3sO90OBxK62F736AcJTPuzm6h0ejoCOfhZ8pyGWtcYPL78kJ pK12UcdZj2yZWY6yrwTH/Jl+/zG1hU+5xELX9OY8ZCTYRQ7kDV7pPlsHvdoX2/SljVQjRswXpoF irEzMXzCc68McAmVs4uKzzfBvoPNl7FGfsF1o1TVkhbUIwFH3dVcGI6uzJ7c1RJoCiOEJoT0Bkb 4nbqtRzezm+5PWCn/Jh4CuaOiaPxmQ/DesQU4QpFP/jfQg2Md1v+eSgHSFT7UgUfpmMhf0jIyhn it+tR6785Js0T3j7k5CjbCt1DwMthDY8otx5MA789aiYP95Q= X-Received: by 2002:a05:6000:40c9:b0:3a4:ef70:e0e1 with SMTP id ffacd0b85a97d-3a572e897camr7732324f8f.55.1750083999568; Mon, 16 Jun 2025 07:26:39 -0700 (PDT) X-Google-Smtp-Source: AGHT+IELzKc0dIQdYFnjNJSpzNmGnjL9tXEIqxyGsvGT7be6pTwRa2ROwBpc3G5nO8T5y+xiz3UZiQ== X-Received: by 2002:a05:6000:40c9:b0:3a4:ef70:e0e1 with SMTP id ffacd0b85a97d-3a572e897camr7732303f8f.55.1750083999132; Mon, 16 Jun 2025 07:26:39 -0700 (PDT) Received: from ?IPV6:2003:d8:2f25:bd00:949:b5a9:e02a:f265? (p200300d82f25bd000949b5a9e02af265.dip0.t-ipconnect.de. [2003:d8:2f25:bd00:949:b5a9:e02a:f265]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a568b28240sm11292833f8f.72.2025.06.16.07.26.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Jun 2025 07:26:38 -0700 (PDT) Message-ID: <51662e0b-4ca2-4841-b8ba-cbf32178eea2@redhat.com> Date: Mon, 16 Jun 2025 16:26:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 1/4] mm/mempolicy: Expose policy_nodemask() in include/linux/mempolicy.h To: Bijan Tabatabai Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, sj@kernel.org, akpm@linux-foundation.org, corbet@lwn.net, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, bijantabatab@micron.com, venkataravis@micron.com, emirakhur@micron.com, ajayjoshi@micron.com, vtavarespetr@micron.com, damon@lists.linux.dev References: <20250612181330.31236-1-bijan311@gmail.com> <20250612181330.31236-2-bijan311@gmail.com> <5a50eeba-b26d-4913-8016-45278608a1ee@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz 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+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: sdQW8G3dorsYYuCYRrerekwwA1yvDrTVxGzvwDk5hTk_1750084000 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D1A9B140004 X-Stat-Signature: rs35xhd8u4c34uw98fh7jfomty5ftoca X-Rspam-User: X-HE-Tag: 1750084004-829122 X-HE-Meta: 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 etVBCVi1 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 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: List-Subscribe: List-Unsubscribe: On 16.06.25 16:16, Bijan Tabatabai wrote: > On Mon, Jun 16, 2025 at 4:46 AM David Hildenbrand wrote: >> >> On 13.06.25 18:33, Bijan Tabatabai wrote: >>> On Fri, Jun 13, 2025 at 8:45 AM David Hildenbrand wrote: >>>> >>>> On 12.06.25 20:13, Bijan Tabatabai wrote: > [...] >> Hi, >> >>> >>> I did not use get_vma_policy or mpol_misplaced, which I believe is the >>> closest function that exists for what I want in this patch, because >>> those functions >> >> I think what you mean is, that you are performing an rmap walk. But >> there, you do have a VMA + MM available (stable). >> >>> seem to assume they are called inside of the task that the folio/vma >>> is mapped to. >> >> But, we do have a VMA at hand, so why would we want to ignore any set >> policy? (I think VMA policies so far only apply to shmem, but still). >> >> I really think you want to use get_vma_policy() instead of the task policy. > > Sorry, I think I misunderstood you before. You are right, we should > consider the VMA policy before using the task policy. I will do this > in the next revision. > >> >>> More specifically, mpol_misplaced assumes it is being called within a >>> page fault. >>> This doesn't work for us, because we call it inside of a kdamond process. >> >> Right. >> >> But it uses the vmf only for ... >> >> 1) Obtaining the VMA >> 2) Sanity-checking that the ptlock is held. >> >> Which, you also have during the rmap walk. > > There is another subtle dependency in get_vma_policy. > It first checks if a VMA policy exists, and if it doesn't, it uses the > task policy of the current task, which doesn't make sense when called > by a kdamond thread. Indeed, anything that depends on current task / nid / cpu might require care. -- Cheers, David / dhildenb