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(p200300cbc7081d0099ec96567475678d.dip0.t-ipconnect.de. [2003:cb:c708:1d00:99ec:9656:7475:678d]) by smtp.gmail.com with ESMTPSA id n44-20020a05600c502c00b004083a105f27sm18382468wmr.26.2023.11.28.06.09.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Nov 2023 06:09:12 -0800 (PST) Message-ID: <137902b6-24dc-4d51-9be2-6f94aa9dbc3a@redhat.com> Date: Tue, 28 Nov 2023 15:09:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND PATCH v7 00/10] Small-sized THP for anonymous memory To: Ryan Roberts , John Hubbard , Alistair Popple Cc: Matthew Wilcox , Andrew Morton , Yin Fengwei , Yu Zhao , Catalin Marinas , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" , David Rientjes , Vlastimil Babka , Hugh Dickins , Kefeng Wang , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20231122162950.3854897-1-ryan.roberts@arm.com> <9c8f6d2a-7ed8-45d2-9684-d77489bd99b8@redhat.com> <26c361bc-6d87-4a57-9fae-ef635c9039c7@redhat.com> <87sf4rppuc.fsf@nvdebian.thelocal> <51e6c9f1-e863-464b-b5f3-d7f60a7ebed6@arm.com> <58af512c-3d7d-4774-88f7-6336c9384b61@arm.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: <58af512c-3d7d-4774-88f7-6336c9384b61@arm.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: 8bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 36EAD10004D X-Stat-Signature: wbsdsux3rmk4yr5gmi616iecodb6a351 X-Rspam-User: X-HE-Tag: 1701180557-419811 X-HE-Meta: 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 jMfzB7cM fMhisFeSkqZdhvXZzDeRvBm+ZFv7FrECzpmP38+PsdqKWfjEsZiYVey1tnBFa9+aTwQOvjbleqW747s4jQp+r8MD/N3Zt4UYh1+/RM3fOa8gqMDvsTgmj0ybwmbXAPCQ3vwSbrikrjrmqv//4XqVpxjQVapZY3RSaMkp0S85ACMmKyK/MSaejsgosmY0KITwiUv4vOyaeVH//Oo0y8tlW/UC27wEFtT7ILKVOpWP80OIe1XOGr6zhHbwDdQhVMV040jUXJzO2ArvSASqsmppLf+R7cKnN31AaYu7N8XGcRH0bHeQpPagNMC6M8iVahQMnBg5/yBd+zmq/TmUvyuNbyqdZfb2eF+qzEQzpVIKlBEydFks8QvHekt7gIMM1ZZwRdtJthn0odRh1nBcqkB5wdR3nFYE5FzdDQN3Ykv2OBkPxfwObhhINbcvhNckCAI/iUKauBAbcT4PRwkC7mDLLJthLaZvhhPb7C+RRmCFTzkb+BiX4X66oZ4iBkQ== 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 28.11.23 13:15, Ryan Roberts wrote: > On 28/11/2023 08:48, David Hildenbrand wrote: >> >>>> >>>> Agreed. We are bikeshedding here. But if we really can't swallow "small-sized >>>> THP" then perhaps the most efficient way to move this forwards is to review the >>>> documentation (where "small-sized THP" appears twice in order to differentiate >>>> from PMD-sized THP) - its in patch 3. Perhaps it will be easier to come up with >>>> a good description in the context of those prose? Then once we have that, >>>> hopefully a term will fall out that I'll update the commit logs with. >>>> >>> >>> I will see you over in patch 3, then. I've already looked at it and am going >>> to suggest a long and a short name. The long name is for use in comments and >>> documentation, and the short name is for variable fragments: >>> >>>       Long name:  "pte-mapped THPs" >>>       Short names: pte_thp, or pte-thp >> >> The issue is that any THP can be pte-mapped, even a PMD-sized THP. However, the >> "natural" way to map a PMD-sized THP is using a PMD. >> > > How about we just stop trying to come up with a term for the "small-sized THP" > vs "PMD-sized THP" and instead invent a name that covers ALL THP: > > "multi-size THP" vs "PMD-sized THP". > > Then in the docs we can talk about how multi-size THP introduces the ability to > allocate memory in blocks that are bigger than a base page but smaller than > traditional PMD-size, in increments of a power-of-2 number of pages. So you're thinking of something like "multi-size THP" as a feature name, and stating that for now we limit it to <= PMD size. mTHP would be the short name? For the stats, we'd document that "AnonHugePages" and friends only count traditional PMD-sized THP for historical reasons -- and that AnonHugePages should have been called AnonHugePmdMapped (which we could still add as an alias and document why AnonHugePages is weird). Regarding new stats, maybe an interface that indicates the actual sizes would be best. As discussed, extending the existing single-large-file statistics might not be possible and we'd have to come up with a new interface, that maybe completely lacks "AnonHugePages" and directly goes for the individual sizes. -- Cheers, David / dhildenb