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(p200300cbc7383c008b014fd9b833e1e9.dip0.t-ipconnect.de. [2003:cb:c738:3c00:8b01:4fd9:b833:e1e9]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43ec36699e0sm132802575e9.35.2025.04.07.07.46.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Apr 2025 07:46:50 -0700 (PDT) Message-ID: <9326367c-977d-4d55-80bd-f1ad3673f375@redhat.com> Date: Mon, 7 Apr 2025 16:46:48 +0200 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 v3 0/6] KVM: guest_memfd: support for uffd minor To: "Liam R. Howlett" , Nikita Kalyazin , Ackerley Tng , Vishal Annapurve , Fuad Tabba , akpm@linux-foundation.org, pbonzini@redhat.com, shuah@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, muchun.song@linux.dev, hughd@google.com, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, jack@suse.cz, lorenzo.stoakes@oracle.com, jannh@google.com, ryan.roberts@arm.com, jthoughton@google.com, peterx@redhat.com, graf@amazon.de, jgowans@amazon.com, roypat@amazon.co.uk, derekmn@amazon.com, nsaenz@amazon.es, xmarcalx@amazon.com References: <20250404154352.23078-1-kalyazin@amazon.com> <2iggdfimgfke5saxs74zmfrswgrxmmsyxzphq4mdfpj54wu4pl@5uiia4pzkxem> <63j2cdjh6oxzb5ehtetiaolobp6zzev7emgqvvfkf5tuwlnspx@7h5u4nrqwvsc> <2bohfxnbthvf3w4kz5u72wj5uxh5sb5s3mbhdk5eg2ingkpkqg@ylykphugpydy> From: David Hildenbrand Content-Language: en-US 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: <2bohfxnbthvf3w4kz5u72wj5uxh5sb5s3mbhdk5eg2ingkpkqg@ylykphugpydy> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 07.04.25 16:24, Liam R. Howlett wrote: > * Nikita Kalyazin [250407 10:05]: >> > > ... > >>> >>> All of this is extremely confusing because the onus of figuring out what >>> the final code will look like is put on the reviewer. As it is, we have >>> issues with people not doing enough review of the code (due to limited >>> time). One way to get reviews is to make the barrier of entry as low as >>> possible. >>> >>> I spent Friday going down a rabbit hole of patches referring to each >>> other as dependencies and I gave up. It looks like I mistook one set of >>> patches as required vs them requiring the same in-flight ones as your >>> patches. >>> >>> I am struggling to see how we can adequately support all of you given >>> the way the patches are sent out in batches with dependencies - it is >>> just too time consuming to sort out. >> >> I'm happy to do whatever I can to make the review easier. I suppose the >> extreme case is to wait for the dependencies to get accepted, effectively >> serialising submissions, but that slows the process down significantly. For >> example, I received very good feedback on v1 and v2 of this series and was >> able to address it instead of waiting for the dependency. Would including >> the required patches directly in the series help? My only concern is in >> that case the same patch will be submitted multiple times (as a part of >> every depending series), but if it's better, I'll be doing that instead. > > Don't resend patches that someone else is upstreaming, that'll cause > other problems. > > Three methods come to mind: > > 1. As you stated, wait for the dependencies to land. This is will mean > what you are working against is well tested and won't change (and you > won't have to re-spin due to an unstable base). > > 2. Combine them into a bigger patch set. I can then pull one patch set > and look at the parts of interest to the mm side. > > 3. Provide a git repo with the necessary changes together. > > I think 2 and 3 together should be used for the guest_memfd patches. > Someone needs to be managing these to send upstream. See the discussion > in another patch set on guest_memfd here [1]. The issue is that most extensions are fairly independent from each other, except that they built up on Fuad's mmap support, Sending all together as one thing might not be the best option. Once basic mmap support is upstream, some of the extensions (e.g., directmap removal) can go in next. So until that is upstream, I agree that tagging the stuff that builds up on that is the right thing to do, and providing git trees is another very good idea. I'll prioritize getting Fuad's mmap stuff reviewed. (I keep saying that, I know) -- Cheers, David / dhildenb