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[195.231.47.232]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49cf7740d44sm847238405e9.15.2026.09.08.04.26.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Sep 2026 04:26:53 -0700 (PDT) Message-ID: <3e210ef7-f807-4de7-935d-09441710acbd@redhat.com> Date: Tue, 8 Sep 2026 13:26:52 +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 Subject: Re: [PATCH net-next] net: run netdev work under the ops-compat lock To: Jakub Kicinski Cc: netdev@vger.kernel.org, edumazet@google.com, andrew+netdev@lunn.ch, horms@kernel.org, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, sdf@fomichev.me, kuniyu@google.com, linux-doc@vger.kernel.org, davem@davemloft.net References: <20260904180058.3803849-1-kuba@kernel.org> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20260904180058.3803849-1-kuba@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/4/26 8:00 PM, Jakub Kicinski wrote: > netdev_work_proc() took rtnl_lock() for the whole batch, forcing > even ops-locked drivers onto rtnl just to run their rx_mode / ndo_work > callbacks. Take the per-device ops-compat lock instead: the instance > lock for ops-locked drivers, rtnl_lock for the rest. That's what the > callbacks already assert (e.g. netif_rx_mode_run() asserts > netdev_assert_locked_ops_compat()), and non-ops-locked work > such as vlan ndo_work keeps rtnl, since its compat lock resolves > to rtnl anyway. > > Without this adding more uses of ndo_work, for cases which don't > need rtnl_lock feels like a step back. > > We can drop the comment about the extra ref now, with the relocking > it's a necessity. > > Signed-off-by: Jakub Kicinski Dump question: can the `netdev_work_list` work list grow significantly under non pathological conditions? netdev_work_proc is now going to acquire and release the rtnl lock n-times for non ops-enabled drivers. Would it be overkill trying to acquire the rtnl lock at most once (i.e. keeping the netdev_need_ops_lock() and legacy drivers on separate list and process them accordingly?) /P