f52ac7028b
Here we add support for multi-buffer XDP handling in Striding RQ, which is our default out-of-the-box RQ type. Before this series, loading such an XDP program would fail, until you switch to the legacy RQ (by unsetting the rx_striding_rq priv-flag). To overcome the lack of headroom and tailroom between the strides, we allocate a side page to be used for the descriptor (xdp_buff / skb) and the linear part. When an XDP program is attached, we structure the xdp_buff so that it contains no data in the linear part, and the whole packet resides in the fragments. In case of XDP_PASS, where an SKB still needs to be created, we copy up to 256 bytes to its linear part, to match the current behavior, and satisfy functions that assume finding the packet headers in the SKB linear part (like eth_type_trans). Performance testing: Packet rate test, 64 bytes, 32 channels, MTU 9000 bytes. CPU: Intel(R) Xeon(R) Platinum 8380 CPU @ 2.30GHz. NIC: ConnectX-6 Dx, at 100 Gbps. +----------+-------------+-------------+---------+ | Test | Legacy RQ | Striding RQ | Speedup | +----------+-------------+-------------+---------+ | XDP_DROP | 101,615,544 | 117,191,020 | +15% | +----------+-------------+-------------+---------+ | XDP_TX | 95,608,169 | 117,043,422 | +22% | +----------+-------------+-------------+---------+ Reviewed-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> 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.