Re: [PATCH net-next v2 2/5] vsock/virtio: amortize RX socket locking for stream packets

[sashiko-bot@kernel.org]

> The virtio-vsock RX worker currently acquires and releases the socket lock
> for every received packet. Keep the lock held while processing a bounded
> run of packets that belongs to the same socket.
> 
> Only ordinary RW packets for an established STREAM socket whose transport
> and protocol remain unchanged are eligible. Control packets, SEQPACKET
> traffic, state or transport changes, malformed packets, and sockets whose
> protocol has been replaced end the active batch and retain their existing
> handling.
> 
> Serialize the initial eligibility check with sk_callback_lock because
> sockmap removal restores the protocol without taking the socket lock.
> 
> Limit each batch to 64 packets or 64KB of payload, bounding the work under
> one socket lock. Keep the lookup reference until the batch finishes.
> 
> Keep a batch only while another skb metadata charge fits in the receive
> buffer. Share this predicate with virtio_transport_inc_rx_pkt(). When an
> enqueued skb consumes the final metadata slot, finish the batch and release
> the socket lock before processing another packet, restoring the reader's
> scheduling opportunity from the per-packet path.
> 
> The virtqueue callback remains a queue_work() callback. Batching runs only
> in the process-context RX worker.
> 
> Introduce virtio_transport_rx_batch_finish() to tear down the batch and
> release the socket lock and lookup reference.
> 
> Signed-off-by: Jia Jia <physicalmtea@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261010142247.99223-1-physicalmtea@gmail.com?part=2