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Fri, 21 Mar 2025 04:15:01 -0700 (PDT) Message-ID: Date: Fri, 21 Mar 2025 05:14:59 -0600 Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC -next 00/10] Add ZC notifications to splice and sendfile To: Christoph Hellwig , Joe Damato , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, asml.silence@gmail.com, linux-fsdevel@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, kuba@kernel.org, shuah@kernel.org, sdf@fomichev.me, mingo@redhat.com, arnd@arndb.de, brauner@kernel.org, akpm@linux-foundation.org, tglx@linutronix.de, jolsa@kernel.org, linux-kselftest@vger.kernel.org References: <20250319001521.53249-1-jdamato@fastly.com> <2d68bc91-c22c-4b48-a06d-fa9ec06dfb25@kernel.dk> <19e3056c-2f7b-4f41-9c40-98955c4a9ed3@kernel.dk> From: Jens Axboe Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/20/25 11:56 PM, Christoph Hellwig wrote: >> I don't know the entire historical context, but I presume sendmsg >> did that because there was no other mechanism at the time. > > At least aio had been around for about 15 years at the point, but > networking folks tend to be pretty insular and reinvent things. Yep... >> It seems like Jens suggested that plumbing this through for splice >> was a possibility, but sounds like you disagree. > > Yes, very strongly. And that is very much not what I suggested, fwiw. >> As mentioned above and in other messages, it seems like it is >> possible to improve the networking parts of splice (and therefore >> sendfile) to make them safer to use without introducing a new system >> call. >> >> Are you saying that you are against doing that, even if the code is >> network specific (but lives in fs/)? > > Yes. > > Please take the work and integrate it with the kiocb-based system > we use for all other in-kernel I/O that needs completion notifications > and which makes it trivial to integate with io_uring instead of > spreading an imcompatible and inferior event system. Exactly, this is how we do async IO elsewhere, not sure why networking needs to be special here, and definitely not special in a good way. -- Jens Axboe