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([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-386219096adsm13599770f8f.85.2024.12.09.07.03.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Dec 2024 07:04:00 -0800 (PST) Message-ID: Date: Mon, 9 Dec 2024 16:03:59 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] MAINTAINERS: group all VMA-related files into the VMA section To: Lorenzo Stoakes , Jann Horn Cc: Vlastimil Babka , Andrew Morton , "Liam R . Howlett" , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20241206191600.45119-1-lorenzo.stoakes@oracle.com> <23d3d7f6-d6d1-430e-8ea0-ccae76b253fd@redhat.com> <41a14051-75ee-4de3-863c-d0532aa7e3aa@suse.cz> <1e4c3e31-ea9a-4af4-83f9-15a882732e69@redhat.com> <71beb3d1-21ac-4037-8363-6484c0c333b8@lucifer.local> <81fc4cd1-55f4-4569-aef7-0b0da9684fdf@lucifer.local> Content-Language: en-US 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: <81fc4cd1-55f4-4569-aef7-0b0da9684fdf@lucifer.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 09.12.24 15:45, Lorenzo Stoakes wrote: > On Mon, Dec 09, 2024 at 03:38:28PM +0100, Jann Horn wrote: >> On Mon, Dec 9, 2024 at 3:11 PM Lorenzo Stoakes >> wrote: >>> On Mon, Dec 09, 2024 at 03:00:08PM +0100, David Hildenbrand wrote: >>>> On 09.12.24 14:25, Vlastimil Babka wrote: >>>>> On 12/9/24 10:16, David Hildenbrand wrote: >>>>>> On 06.12.24 20:16, Lorenzo Stoakes wrote: >>>>>>> There are a number of means of interacting with VMA operations within mm, >>>>>>> and we have on occasion not been made aware of impactful changes due to >>>>>>> these sitting in different files, most recently in [0]. >>>>>>> >>>>>>> Correct this by bringing all VMA operations under the same section in >>>>>>> MAINTAINERS. Additionally take the opportunity to combine MEMORY MAPPING >>>>>>> with VMA as there needn't be two entries as they amount to the same thing. >>>>>>> >>>>>>> [0]:https://lore.kernel.org/linux-mm/CAG48ez0siYGB8GP5+Szgj2ovBZAkL6Zi4n6GUAjzzjFV9LTkRQ@mail.gmail.com/ >>>>>>> >>>>>>> Signed-off-by: Lorenzo Stoakes >>>>>>> --- >>>>>>> MAINTAINERS | 19 +++++++------------ >>>>>>> 1 file changed, 7 insertions(+), 12 deletions(-) >>>>>>> >>>>>>> diff --git a/MAINTAINERS b/MAINTAINERS >>>>>>> index 1e930c7a58b1..95db20c26f5f 100644 >>>>>>> --- a/MAINTAINERS >>>>>>> +++ b/MAINTAINERS >>>>>>> @@ -15060,18 +15060,6 @@ F: tools/mm/ >>>>>>> F: tools/testing/selftests/mm/ >>>>>>> N: include/linux/page[-_]* >>>>>>> >>>>>>> -MEMORY MAPPING >>>>>>> -M: Andrew Morton >>>>>>> -M: Liam R. Howlett >>>>>>> -M: Lorenzo Stoakes >>>>>>> -R: Vlastimil Babka >>>>>>> -R: Jann Horn >>>>>>> -L: linux-mm@kvack.org >>>>>>> -S: Maintained >>>>>>> -W: http://www.linux-mm.org >>>>>>> -T: git git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm >>>>>>> -F: mm/mmap.c >>>>>>> - >>>>>>> MEMORY TECHNOLOGY DEVICES (MTD) >>>>>>> M: Miquel Raynal >>>>>>> M: Richard Weinberger >>>>>>> @@ -25028,6 +25016,13 @@ L: linux-mm@kvack.org >>>>>>> S: Maintained >>>>>>> W: https://www.linux-mm.org >>>>>>> T: git git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm >>>>>>> +F: mm/madvise.c >>>>>>> +F: mm/mlock.c >>>>>>> +F: mm/mmap.c >>>>>>> +F: mm/mprotect.c >>>>>>> +F: mm/mremap.c >>>>>>> +F: mm/mseal.c >>>>>>> +F: mm/msync.c >>>>>> >>>>>> Not sure about mprotect.c, mlock.c and madvise.c, though. I'd claim that >>>>>> the real "magic" they perform is in page table handling and not >>>>>> primarily VMA handling (yes, both do VMA changes, but they are the >>>>>> "easy" part ;) ). >>>>> >>>>> I'd think that moving vma files into MEMORY MAPPING (and not the other way) >>>>> would result in a better overal name, that would be a better fit for the >>>>> newly added files too? >>>> >>>> Maybe. I think vma.c should likely have a different set of maintainers than >>>> madvise.c and mprotect.c. (again, the magic is in page table modifications) >>> >>> The bulk of the logic in mremap.c is related to page tables so by this >>> logic then, that is out too, right? >> >> FWIW, I think technically you can have multiple entries in MAINTAINERS >> that cover the same file, maybe that would make sense for files that >> belong to multiple parts of the kernel? Or maybe I'm making things too >> complicated and it'd be simpler to have some kind of more generic >> "core MM for userspace mappings" entry or such. > > I think it's faintly ludicrous to separate things on the basis of whether > they explicitly manipulate one part of the kernel or another, and it'd be > an odd thing to be trusted with one 'portion' of a file based on some fuzzy > sense of which bits are 'magic' and therefore out of bounds and which are > presumably not... > > I don't think it makes sense to separate the 'VMA' bits from these files > other than perhaps refactoring things a bit (badly needed actually). > > The page table manipulation very sorely needs improvement and > de-duplication, I am somewhat taken aback that it is thought that I might > not be able to do so given I had already paid serious consideration to > doing work in this area based on guard page work (not sure if that work > would now be welcome?) > > To me I politely disagree with the assessment made here, but if a senior > member of the kernel objects of course I'll withdraw it. > > But yeah I don't think that's workable. We will just have to hope that we > notice mremap changes that might be problematic going forward, I might > therefore update my lei settings accordingly... > I have the feeling you take this personally; please don't. Maybe my other mail with "VMA users" vs. "basic VMA functionality" makes it clearer what I mean. For example, mm/userfaultfd.c also performs VMA modifications. kernel/fork.c does a bunch of that. I neither think these should go under VMA nor that it should be split up. Maybe there is a better way to split up things or rework the code; likely we'd want this code that works on VMAs to have a clean interface with the core vma logic in vma.c, if the current way of handling it is a problem for you. -- Cheers, David / dhildenb