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[79.224.244.72]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a35ca8caaasm15564347f8f.83.2025.05.20.02.44.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 May 2025 02:44:20 -0700 (PDT) Message-ID: <746e8123-2332-41c8-851b-787cb8c144a1@redhat.com> Date: Tue, 20 May 2025 11:43:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 0/5] mm, bpf: BPF based THP adjustment To: Yafang Shao , akpm@linux-foundation.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: bpf@vger.kernel.org, linux-mm@kvack.org References: <20250520060504.20251-1-laoar.shao@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: <20250520060504.20251-1-laoar.shao@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ItqvIj8FuX90SnmVzIJkAt0Rf2mdLJ8WwkQnyWHiJYk_1747734262 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: as1ddp7cbsyrwdehsaqmeehxgeg9apiu X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 1DDF9C000F X-HE-Tag: 1747734264-370484 X-HE-Meta: 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 L9WS673d 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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: > Conclusion > ---------- > > Introducing a new "bpf" mode for BPF-based per-task THP adjustments is the > most effective solution for our requirements. This approach represents a > small but meaningful step toward making THP truly usable—and manageable—in > production environments. A new "bpf" mode sounds way too special. We currently have: never -> never madvise -> MADV_HUGEPAGE, except PR_SET_THP_DISABLE always -> always, except PR_SET_THP_DISABLE and MADV_NOHUGEPAGE Whatever new mode we add, it should honor PR_SET_THP_DISABLE + MADV_NOHUGEPAGE. So, if we want another way to enable things, it would live between "never" and "madvise". I'm wondering how we could make that generic: likely we want this new mechanism to *not* be triggerable by the process itself (madvise). I am not convinced bpf is the answer here ... -- Cheers, David / dhildenb