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[76.102.12.149]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2b6b34c0f7fsm24054451eec.3.2026.01.21.20.07.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Jan 2026 20:07:12 -0800 (PST) Date: Wed, 21 Jan 2026 20:07:11 -0800 From: Stanislav Fomichev To: Jakub Kicinski Cc: Bobby Eshleman , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , Neal Cardwell , David Ahern , Mina Almasry , Arnd Bergmann , Jonathan Corbet , Andrew Lunn , Shuah Khan , Donald Hunter , Stanislav Fomichev , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, asml.silence@gmail.com, matttbe@kernel.org, skhawaja@google.com, Bobby Eshleman Subject: Re: [PATCH net-next v10 4/5] net: devmem: document NETDEV_A_DMABUF_AUTORELEASE netlink attribute Message-ID: References: <20260115-scratch-bobbyeshleman-devmem-tcp-token-upstream-v10-0-686d0af71978@meta.com> <20260115-scratch-bobbyeshleman-devmem-tcp-token-upstream-v10-4-686d0af71978@meta.com> <20260120163650.5a962648@kernel.org> <20260121173512.748e2155@kernel.org> <20260121185021.446b00e8@kernel.org> <20260121194615.33dc0812@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260121194615.33dc0812@kernel.org> On 01/21, Jakub Kicinski wrote: > On Wed, 21 Jan 2026 19:25:27 -0800 Bobby Eshleman wrote: > > > > That is correct, neither is true. If the two sockets share a binding the > > > > kernel doesn't care which socket received the token or which one > > > > returned it. No token <> socket association. There is no > > > > queued-but-not-read race either. If any tokens are not returned, as long > > > > as all of the binding references are eventually released and all sockets > > > > that used the binding are closed, then all references will be accounted > > > > for and everything cleaned up. > > > > > > Naming is hard, but I wonder whether the whole feature wouldn't be > > > better referred to as something to do with global token accounting > > > / management? AUTORELEASE makes sense but seems like focusing on one > > > particular side effect. > > > > Good point. The only real use case for autorelease=on is for backwards > > compatibility... so I thought maybe DEVMEM_A_DMABUF_COMPAT_TOKEN > > or DEVMEM_A_DMABUF_COMPAT_DONTNEED would be clearer? > > Hm. Maybe let's return to naming once we have consensus on the uAPI. > > Does everyone think that pushing this via TCP socket opts still makes > sense, even tho in practice the TCP socket is just how we find the > binding? I'm not a fan of the existing cmsg scheme, but we already have userspace using it, so getting more performance out of it seems like an easy win?