On Thu, 11 Jan 2024, Liming Sun wrote: > Starting from Linux 5.16 kernel, Tx timeout mechanism was added > in the virtio_net driver which prints the "Tx timeout" warning > message when a packet stays in Tx queue for too long. Below is an > example of the reported message: > > "[494105.316739] virtio_net virtio1 tmfifo_net0: TX timeout on > queue: 0, sq: output.0, vq: 0×1, name: output.0, usecs since > last trans: 3079892256". > > This issue could happen when external host driver which drains the > FIFO is restared, stopped or upgraded. To avoid such confusing > "Tx timeout" messages, this commit adds logic to drop the outstanding > Tx packet if it's not able to transmit in two seconds due to Tx FIFO > full, which can be considered as congestion or out-of-resource drop. > > This commit also handles the special case that the packet is half- > transmitted into the Tx FIFO. In such case, the packet is discarded > with remaining length stored in vring->rem_padding. So paddings with > zeros can be sent out when Tx space is available to maintain the > integrity of the packet format. The padded packet will be dropped on > the receiving side. > > Signed-off-by: Liming Sun <limings@xxxxxxxxxx> > --- > v2->v3: > Updates for Ilpo's comments: > - Revises commit message to avoid confusion. > v2: Fixed formatting warning > v1: Initial version Thanks, the commit message makes much more sense now! Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> -- i.
