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15070919f8
Adding ethtool stats for when XDP transmitted packets overrun the TX queue. This is recorded separately for XDP_TX and ndo_xdp_xmit. This is an important aid for troubleshooting XDP based setups. It is currently a known weakness and property of XDP that there isn't any push-back or congestion feedback when transmitting frames via XDP. It's easy to realise when redirecting from a higher speed link into a slower speed link, or simply two ingress links into a single egress. The situation can also happen when Ethernet flow control is active. For testing the patch and provoking the situation to occur on my Espressobin board, I configured the TX-queue to be smaller (434) than RX-queue (512) and overload network with large MTU size frames (as a larger frame takes longer to transmit). Hopefully the upcoming XDP TX hook can be extended to provide insight into these TX queue overflows, to allow programmable adaptation strategies. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.