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 037AFC3ABDD for ; Tue, 20 May 2025 15:00:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 959B56B0095; Tue, 20 May 2025 11:00:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 90A076B0099; Tue, 20 May 2025 11:00:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7D1936B009A; Tue, 20 May 2025 11:00:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 56C5F6B0095 for ; Tue, 20 May 2025 11:00:13 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 02D095A246 for ; Tue, 20 May 2025 15:00:12 +0000 (UTC) X-FDA: 83463596706.04.8B0555C Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf30.hostedemail.com (Postfix) with ESMTP id 594908000B for ; Tue, 20 May 2025 15:00:10 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=c0RmGBTf; spf=pass (imf30.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747753210; 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=i2s5zJn6VDiqf+Oamn2t1mC0KNMDw8+pdHeLY6X/rWw=; b=C4bYv7uSA+smrE9pwme1TyBCCObGJySXYdua9wz4HtZm0WuoVECn6NeqZj52dNlKDRStrl vlO/CdsFs6m9IYyObim6JmhRtSnx56wjsd/8GjS/9CYcU9NRXxNilNmLEzc7u5G8/05LDk azMZLSPTCt+VATwXI1e9x5707xY9Ag0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747753210; a=rsa-sha256; cv=none; b=56akK+Q+va537dAMI2kI3jzGuhbfLtZ/jEmBbbrnzhk+4Qnh+dV74mz0wN4IqJLMmXqtGJ 8azr8pDEX2AsVHrkCIf2dFDVKA4bOrEqwfJeyp4e9HsYNrmiKDptimp0/1M7Cry9l3G0Qk SxOMhnPyaVOISflQa9vE5hSK6UrjTIw= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=c0RmGBTf; spf=pass (imf30.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1747753209; 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=i2s5zJn6VDiqf+Oamn2t1mC0KNMDw8+pdHeLY6X/rWw=; b=c0RmGBTfqOOlBuNpmLs0tufr/7bJlUtSAEO/1ZNUdlVzudDByIHPemCQnhmpUs890zE0jE d+rwQfV6TMS8XW/UoAmaJrE2q/XIMfdIgxt0puj4EaVuQwlWewuoml4tlqq7L0w+jl1hD3 WW0wKCk1HYmd0RPiROZrWRN4u0x2aB0= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-665-hqTKFvUQNA2XCcqsXqpZqQ-1; Tue, 20 May 2025 11:00:08 -0400 X-MC-Unique: hqTKFvUQNA2XCcqsXqpZqQ-1 X-Mimecast-MFC-AGG-ID: hqTKFvUQNA2XCcqsXqpZqQ_1747753207 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-43e9a3d2977so42854755e9.1 for ; Tue, 20 May 2025 08:00:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747753207; x=1748358007; 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=i2s5zJn6VDiqf+Oamn2t1mC0KNMDw8+pdHeLY6X/rWw=; b=AVRekpwBORT6zcrNv1RNbNwGGGbfkBPBJKZDktrsYTeROJ4r/iH/D3/9YQS0hbVXTK 2NCrpuWOr5YoVAS14/yqaodxTANGtGZTw1OAXPW6szGYtcyTtJwntGTwHzJODe1B0T2/ 2W6seXrQgnWzLI/nt/I7JtGYVW8/UbRny1FgdmJvy5dVS1cDiWKSeqc8ZVKX63rO90Nd gY3ELEvvwiPnPOQwrNF6Fbo4HsMGUbDEcvpT2Zp0YPILICfQBE0IgSCZnxdjC6k97zKr SS4bawTiblOAwBV7h7Uy1ELzemqVLu5ykvMPz0/PNkdsm42l5KDsTV9vZDKicCgkMnod E4/Q== X-Forwarded-Encrypted: i=1; AJvYcCXFl2dYUvT8X5yspTtTuzQlrJAZ7kl2AcA5MtKLzsFXwDnJpT8hYu7awDCkDtXsYPj1JAWklVqdXQ==@kvack.org X-Gm-Message-State: AOJu0Ywnf2Zh8quQDluUfxOo2ORwspHVoCh4+Dbc97Gln+qtJEmSSnHE ufPZhk49PiBO7/iAQT8w48XL2htbUREEbnVz5UckxfxBtgeBA5m46NHP6r2zxLq/Mc2BdTKw6C6 TXNUIotvYYU2RUTyKeGopMmam24wxDSdeOdmvQnfSriYMEuB4kwWy X-Gm-Gg: ASbGnct0OEfykN0iWCPcIDSsTIHnw551sRQ9ZD3EMS59IpZSgArRU7k9z6IdFifD9GH xl+z1KUPtdcNANpVm3pc0koFD5A286UE23nGeNHE+UaSo2f3Y4I+KbjgX5ISKOgxs8WFQBfF4Jv sOiZIiM1ZTLyyaUAdlD6Ks9FGQTsmw0QTVAfbWtQSvKhQn5/TE16WyGjJbPi7/p0wJ5dR5E0fmj wgfqLi84dWOdqD1pysLAisjhv88C9RJsjzrmh0WnhMNaLvrmGhKLywhZV20CeGEIC6NTisLsQjv xEIA9Kw+j2MhIqBH1iMN2F9ukpNckQ0t8QUpIYV8BetYMdphEosp0Aik8gAqTuc2RzSPys03IIk lyZFdeIRvMGCBxDoQjQVAVo0im5j6Qc0D+u+1aVQ= X-Received: by 2002:a05:600c:34d4:b0:442:e0e0:250 with SMTP id 5b1f17b1804b1-442fd67200emr158111215e9.29.1747753207165; Tue, 20 May 2025 08:00:07 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHQDqxiGKA4tkeiSH2PDNWUB5/u9yZfVoEssPnM5TVx5ileUuEXFfJoIauzZIlle9PhXQ+k0g== X-Received: by 2002:a05:600c:34d4:b0:442:e0e0:250 with SMTP id 5b1f17b1804b1-442fd67200emr158110825e9.29.1747753206705; Tue, 20 May 2025 08:00:06 -0700 (PDT) Received: from ?IPV6:2003:d8:2f28:7c00:a95e:ac49:f2ad:ab84? (p200300d82f287c00a95eac49f2adab84.dip0.t-ipconnect.de. [2003:d8:2f28:7c00:a95e:ac49:f2ad:ab84]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-447f78b2f19sm33137685e9.32.2025.05.20.08.00.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 May 2025 08:00:06 -0700 (PDT) Message-ID: Date: Tue, 20 May 2025 17:00:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 0/5] mm, bpf: BPF based THP adjustment To: Usama Arif , Lorenzo Stoakes , Yafang Shao Cc: Matthew Wilcox , Nico Pache , akpm@linux-foundation.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, gutierrez.asier@huawei-partners.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org References: <20250520060504.20251-1-laoar.shao@gmail.com> <2345b8b9-b084-4661-8b55-61fd7fc7de57@lucifer.local> <82f7bca5-384f-41e5-a0fc-0e1e8e260607@gmail.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: <82f7bca5-384f-41e5-a0fc-0e1e8e260607@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: HI3_ZEcL-Sm2OU7S-IDBl7KPdH1x_AQjtOHwZ14hSMs_1747753207 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: 5u5hby551kye7a14pq9snqbig7w6tz8r X-Rspamd-Queue-Id: 594908000B X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1747753210-917454 X-HE-Meta: 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 ewgfHMrZ 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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 20.05.25 16:32, Usama Arif wrote: > > > On 20/05/2025 15:22, Lorenzo Stoakes wrote: >> On Tue, May 20, 2025 at 10:08:03PM +0800, Yafang Shao wrote: >>> On Tue, May 20, 2025 at 9:10 PM Matthew Wilcox wrote: >>>> >>>> On Tue, May 20, 2025 at 03:25:07PM +0800, Yafang Shao wrote: >>>>> The challenge we face is that our system administration team doesn't >>>>> permit enabling THP globally in production by setting it to "madvise" >>>>> or "always". As a result, we can only experiment with your feature on >>>>> our test servers at this stage. >>>> >>>> That's a you problem. >>> >>> perhaps. >>> >>>> You need to figure out how to influence your >>>> sysadmin team to change their mind; whether it's by talking to their >>>> superiors or persuading them directly. >>> >>> I believe that "practicing" matters more than "talking" or "persuading". >>> I’m surprised your suggestion relies on "talking" ;-) >>> If I understand correctly, we all agree that "talk is cheap", right? >>> >>>> It's not a justification for why >>>> upstream should take this patch. >>> >>> I believe Johannes has clearly explained the challenges the community >>> is currently facing [0]. >>> >>> [0]. https://lore.kernel.org/linux-mm/20250430174521.GC2020@cmpxchg.org/ >> >> (Sorry to interject on your conversation, but :) >> >> I don't think anybody denies we have issues in configuring this stuff >> sensibly. A global-only control isn't going to cut it in the real world it >> seems. >> >> To me as you say yourself, definining the ABI/API here is what really matters, >> and we're right now inundated with several series all at once (you wait for one >> bus then 3 come at once... :). >> >> So this I think, should be the question. >> >> I like the idea of just exposing something like madvise(), which is something >> we're going to maintain indefinitely. >> >> Though any such exposure would in my view would need to be opt-in i.e. have a >> list of MADV_... options that are accepted, as we'd need to very cautiously >> determine which are safe from this context. >> >> Of course then this leads to the whole thing (and I really know very little >> about BPF internals - obviously happy to understand more) of whether we can just >> use the madvise() code direct or what locking we can do or how all that works. >> >> At any rate, a custom thing that is specific as 'switch mode for mTHP pages of >> size X to Y' is just something I'd rather us not tie ourselves to. >> >>> >>> >>> -- >>> Regards >>> >>> Yafang >> >> What do you think re: bpf vs. something like my proposed process_madvise() >> extensions or Usama's proposed prctl()? >> >> Simpler, but really just using madvise functionality and having a means of >> defaulting across fork/exec (notwithstanding Jann's concerns in this area). > > Unfortunately I think the issue is that neither prctl or process_madvise would work > for Yafangs usecase? Its usecase 3 mentioned in [1], i.e. > global system policy=never, process wants "madvise" policy for itself. If the global system policy would be "madvise", you'd need a way to just disable it for processes where you wouldn't ever want them. -- Cheers, David / dhildenb