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 D03DCC04FFE for ; Wed, 8 May 2024 07:09:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0B5DC6B0082; Wed, 8 May 2024 03:09:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 065F36B0083; Wed, 8 May 2024 03:09:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E48DF6B0089; Wed, 8 May 2024 03:09:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id C83D06B0082 for ; Wed, 8 May 2024 03:09:01 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 5BEF9160F3A for ; Wed, 8 May 2024 07:09:01 +0000 (UTC) X-FDA: 82094351682.09.603CCE7 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf06.hostedemail.com (Postfix) with ESMTP id 083B5180018 for ; Wed, 8 May 2024 07:08:58 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=cp2WxqPi; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1715152139; 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=OXKliv38RKyk33UIE1OloI2gQJb7d5lm3TUylexLlhU=; b=ngZ0w43nNGVaHJUCHq8Dw6MkjQ9K/gTgI1Ui79GBnghhLYotJ/wmfJ9fub4lFrlcHD3Ut9 VBEBHi+wr2YOQwg+NBegujE1junxWhJdR1+PiY7VE+e/n5cjKCHQxEGpgTj4nAmLDzaIu+ m9+pC/OOnNAgs9ljGENnYGIfaND0zSQ= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=cp2WxqPi; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1715152139; a=rsa-sha256; cv=none; b=hrJgJFcGozVk31ISu5c1akKXEFl/XvCcHcYC4UuS/hTif+Pe+X3Q0DcR6l1++X2F9hHhiE phTz06X9L5uMZNYK6XYzfO+sqR4UGKXcT4Q1KlXEZiPOj3KfwSqRdBZyLzd7VU1nHJ6VHX 4rqzzqR2TMavsmE5TQ0T4amrWxji87E= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1715152138; 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=OXKliv38RKyk33UIE1OloI2gQJb7d5lm3TUylexLlhU=; b=cp2WxqPif9FvqNAFnL0ISCWcz5TQgo4Mz1Tq/lUG6bwuWvEdhUdT/ZUBRU0iX0trh9G+GT x3VLx4Yo1mY8/4J6SvzlwYQ/pUrZjzCTueNqExrxqJfmvGnnWNIT+tErdck7gdIWhevmqC XEsWbNYw8b0xmi3OaR8NcCkP8D8Fy+o= 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-498-cHMeiZZoMH22e3_gaRnRNw-1; Wed, 08 May 2024 03:08:54 -0400 X-MC-Unique: cHMeiZZoMH22e3_gaRnRNw-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-34d9055c7e0so2708029f8f.3 for ; Wed, 08 May 2024 00:08:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715152133; x=1715756933; 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=OXKliv38RKyk33UIE1OloI2gQJb7d5lm3TUylexLlhU=; b=eJ5aTjdjS+qWkcXaipcBAm555qONNlVxgQhXh0zgea7CD64LPJzSq6thcSSkD+/Ock Z/czcWGs6mWLsz6zFR9g+fbeiWnpALX/EtQW7H7faWHhyNK509Rs304k4ruRnw5b8KEU 7Moi0pRCd8cHahazrYH2bJIkmI+detsUFWN26lxGvVHeEVRf6BZem9qbw8PBWD1zVmzM upfeS87zNy42sBfr8tvWOWkE/Kvn+E/vSo5DuVfdtmNq4OKKnX5CpLfGYg+YBCP6Bl1P jmrlLvaoEUvFUVcJ4QhrSct7Ia+b4rmyWpRSw5MGUMm1ywwg3alr6+WFP1EBwfgfeFiQ vsWw== X-Forwarded-Encrypted: i=1; AJvYcCViC3xhGiB/c4/gAip98kE5CVFyd0sPQjeRIfnVcWkPcemKg3BzGKL3rWo9SdCE93n/21+eok3I6FxbjTUU5DwAPVA= X-Gm-Message-State: AOJu0Yx//AfrXKT4O7N+knX40klqvaaYapQwWPwo5ASLIRQ5Vh85ch5M Auh5vXqzhwB9mXk7R+4Ni+qmfcxUxMXeyhe3oogovIDKV8wTJltk3yhclBDj1VfREjIYD11CCFi 5C/7h9PqH5pz/l8IaP2ZnToIX+eZBVgVeMcxEtHgBwcpwvAP5 X-Received: by 2002:a5d:4904:0:b0:346:92d2:a496 with SMTP id ffacd0b85a97d-34fca42eb91mr1339551f8f.29.1715152133611; Wed, 08 May 2024 00:08:53 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEkQfbqBKr1MxjDAN0f7SWjWAq181oVgHKdyz6l1NGCIZ4y6Y7yr8wG9pNDYxjQNgldNRWNHg== X-Received: by 2002:a5d:4904:0:b0:346:92d2:a496 with SMTP id ffacd0b85a97d-34fca42eb91mr1339526f8f.29.1715152133097; Wed, 08 May 2024 00:08:53 -0700 (PDT) Received: from [192.168.3.108] (p5b0c6bc3.dip0.t-ipconnect.de. [91.12.107.195]) by smtp.gmail.com with ESMTPSA id v23-20020a5d5917000000b00346ceb9e060sm14586294wrd.103.2024.05.08.00.08.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 May 2024 00:08:52 -0700 (PDT) Message-ID: Date: Wed, 8 May 2024 09:08:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/8] mm: shmem: add multi-size THP sysfs interface for anonymous shmem To: Baolin Wang , Ryan Roberts , akpm@linux-foundation.org, hughd@google.com Cc: willy@infradead.org, ioworker0@gmail.com, wangkefeng.wang@huawei.com, ying.huang@intel.com, 21cnbao@gmail.com, shy828301@gmail.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <6b4afed1ef26dbd08ae9ec58449b329564dcef3e.1714978902.git.baolin.wang@linux.alibaba.com> <30329a82-45b9-4e78-8c48-bd56af113786@arm.com> <0b3735bc-2ad7-44f8-808b-37fc90d57199@linux.alibaba.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: <0b3735bc-2ad7-44f8-808b-37fc90d57199@linux.alibaba.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 083B5180018 X-Rspamd-Server: rspam06 X-Stat-Signature: ajp78itoqkm3ya8qmhe6bithbrjuwsxi X-HE-Tag: 1715152138-706899 X-HE-Meta: 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 LlJaszMx 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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 08.05.24 06:45, Baolin Wang wrote: > > > On 2024/5/7 18:52, Ryan Roberts wrote: >> On 06/05/2024 09:46, Baolin Wang wrote: >>> To support the use of mTHP with anonymous shmem, add a new sysfs interface >>> 'shmem_enabled' in the '/sys/kernel/mm/transparent_hugepage/hugepages-kB/' >>> directory for each mTHP to control whether shmem is enabled for that mTHP, >>> with a value similar to the top level 'shmem_enabled', which can be set to: >>> "always", "inherit (to inherit the top level setting)", "within_size", "advise", >>> "never", "deny", "force". These values follow the same semantics as the top >>> level, except the 'deny' is equivalent to 'never', and 'force' is equivalent >>> to 'always' to keep compatibility. >> >> We decided at [1] to not allow 'force' for non-PMD-sizes. >> >> [1] >> https://lore.kernel.org/linux-mm/533f37e9-81bf-4fa2-9b72-12cdcb1edb3f@redhat.com/ >> >> However, thinking about this a bit more, I wonder if the decision we made to >> allow all hugepages-xxkB/enabled controls to take "inherit" was the wrong one. >> Perhaps we should have only allowed the PMD-sized enable=inherit (this is just >> for legacy back compat after all, I don't think there is any use case where >> changing multiple mTHP size controls atomically is actually useful). Applying > > Agree. This is also our usage of 'inherit'. > >> that pattern here, it means the top level can always take "force" without any >> weird error checking. And we would allow "force" on the PMD-sized control but >> not on the others - again this is easy to error check. >> >> Does this pattern make more sense? If so, is it too late to change >> hugepages-xxkB/enabled interface? > > IMO, this sounds reasonable to me. Let's see what others think, David? Likely too late and we should try not to diverge too much from "enabled" for "shmem_enabled". Having that said, to me it's much cleaner to just have "inherit" for all sizes and disallow invalid configurations as discussed. Error checking cannot be too hard unless I am missing something important :) -- Cheers, David / dhildenb