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([2a01:e0a:b41:c160:6a1d:efff:fe52:1959]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-449c576d0a2sm3615047f8f.31.2026.04.30.08.44.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 30 Apr 2026 08:44:54 -0700 (PDT) Message-ID: <3f8d63a3-e39e-48f9-a0d0-517be7c05498@6wind.com> Date: Thu, 30 Apr 2026 17:44:53 +0200 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: nicolas.dichtel@6wind.com Subject: Re: [RFC PATCH net-next 0/3] netns: optionally inherit IPv4 TCP sysctls from old net To: nmreadelf , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, corbet@lwn.net, dsahern@kernel.org Cc: horms@kernel.org, chia-yu.chang@nokia-bell-labs.com, idosch@nvidia.com, ij@kernel.org, brauner@kernel.org, jack@suse.cz, kuniyu@google.com, jlayton@kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, lance.yang@linux.dev, leon.hwang@linux.dev References: From: Nicolas Dichtel Content-Language: en-US Organization: 6WIND In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Le 30/04/2026 à 03:30, nmreadelf a écrit : > a new network namespace starts with built-in TCP defaults. > In container-heavy setups, operators often tune TCP sysctls in init_net and then > need to re-apply the same values for each new netns. > > This series adds an opt-in mechanism to initialize per-netns IPv4 TCP sysctl > settings from init_net at netns creation time. > > Behavior: > > Default is unchanged. > When net.ipv4.netns_inherit_tcp_sysctls=1, new netns inherit > TCP sysctl from old_net. There is the same kind of sysctl for net.{ipv4,ipv6}.conf.{all,default}.*: net.core.devconf_inherit_init_net. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/sysctl/net.rst#n401 I'm not sure if it's acceptable to use this existing entry to control the TCP sysctl. At least, putting the new one in the same place + using the same template for the name + the same values would be nice. Something like net.core.tcp_inherit_init_net. Regards, Nicolas