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([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-434d52cbd42sm192472705e9.38.2024.12.09.06.09.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Dec 2024 06:09:27 -0800 (PST) Message-ID: Date: Mon, 9 Dec 2024 15:09:26 +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 Cc: Andrew Morton , "Liam R . Howlett" , Vlastimil Babka , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20241206191600.45119-1-lorenzo.stoakes@oracle.com> <23d3d7f6-d6d1-430e-8ea0-ccae76b253fd@redhat.com> 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 09.12.24 11:06, Lorenzo Stoakes wrote: > On Mon, Dec 09, 2024 at 10:16:21AM +0100, 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 ;) ). > > And large parts of the VMA logic interface with page tables, see - the entire > 6.12 cycle - around recent changes in mmap() MAP_FIXED - which... the VMA > maintainers fixed :) > > And then there were the issues around VMA and mm locking relating to page > table work which... oh right yeah we had to fix again... :>) > > I mean you can make this argument about probably all of these files (mremap > has -tons- of page table-specific stuff), and then we get back to not being > notified about key changes that interface with memory mapping/VMA which we > end up having to deal with anyway. > > A lot of the reason we have 'magic' in these files anyway is because we > don't have a decent generic page table handler. Not sure I'd actually use > the word 'magic' for that though. > > I am planning to make significant changes to mprotect/mlock soon, which > have some terribly duplicated horrible handling logic, and both are key > considerations in VMA logic as a whole. > > Anyway, as far as I'm concerned page table manipulation after the point of > faulting is completely within the purvue of VMA manipulation and a side > product of it. > > However, can concede mm/madvise.c if you feel strongly about that as that's > a bit blurry, but of course contains a whole bunch of VMA and... page table > manipulation :) I mean it still to me seems very pertinent. > And then we have mprotect.c being heavily used by uffd-wp and NUMA hinting, which don't perform any VMA modification. That's why I don't think the change proposed here is really the right step. >>>> They have much more in common with memory.c, which I wouldn't want to see in >> here either. Hm. > > No, memory.c is really dedicated to fault handling. This is really > different from manipulating page tables in specific cases in my opinion. And fork and such stuff. And if you look into huge_memory.c, we actually moved all of the THP logic for mprotect()/madvise()/... in there. Not sure if something similar should have been done for memory.c, or if the THP stuff should actually also have gone into the respective files. To me it sounds wrong to have VMA maintainers maintain a lot of the code in these files code because these files somehow modify VMAs, sorry. -- Cheers, David / dhildenb