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Tsirkin" To: Simon Schippers Cc: willemdebruijn.kernel@gmail.com, jasowang@redhat.com, eperezma@redhat.com, stephen@networkplumber.org, leiyang@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org Subject: Re: [PATCH net-next v5 0/8] TUN/TAP & vhost_net: netdev queue flow control to avoid ptr_ring tail drop Message-ID: <20250924031105-mutt-send-email-mst@kernel.org> References: <20250922221553.47802-1-simon.schippers@tu-dortmund.de> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250922221553.47802-1-simon.schippers@tu-dortmund.de> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: QAMs5UBPFZCSfKv8ssLv7y7Snwv-o7toOtLLpxWTV5E_1758698323 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 23, 2025 at 12:15:45AM +0200, Simon Schippers wrote: > This patch series deals with TUN, TAP and vhost_net which drop incoming > SKBs whenever their internal ptr_ring buffer is full. Instead, with this > patch series, the associated netdev queue is stopped before this happens. > This allows the connected qdisc to function correctly as reported by [1] > and improves application-layer performance, see our paper [2]. Meanwhile > the theoretical performance differs only slightly: About this whole approach. What if userspace is not consuming packets? Won't the watchdog warnings appear? Is it safe to allow userspace to block a tx queue indefinitely? -- MST