Linux 5.18 Brings Many Networking Changes, New WiFi / Wired Hardware Support

The networking subsystem updates are busy as always with each Linux kernel merge window.

Jakub Kicinski on Wednesday submitted the networking updates for the in-development Linux 5.18 kernel with the changes as usual being a mix of new hardware support, various protocol improvements, and network optimizations. Some of the Linux 5.18 networking highlights are below.

On the WiFi side there is now support for Mediatek MT7916 and MT7921U wireless hardware within the MT76 driver. The BRCMFMAC driver meanwhile has added support for Broadcom BCM43454/6 WiFi. The Intel IOSM driver has added support for the Intel M.2 7360 WWAN card. There is also a lot of new wired networking hardware support including for the Realtek RTL83675 and RTL8367RB-VB, Microchip KSZ8563 switches, Netronome NFP3800 SmartNICs, Fungible SmartNICs, and Mediatek MT8195 switches.

Some of the other driver work includes multi-buffer XDP handling in the Mellanox MLX5 driver, the Realtek R8169 driver will now enable ASPM L1.2 power savings if the system vendor flags it is safe, RJ45 ports handling in the Mellanox MLXSW driver, offloading work for the Marvell Presetera Ethernet driver code, various Intel WiFi (IWLWIFI) additions, background radar detection for the Mediatek MT76 driver, the Realtek RTW89 driver adds AP mode support and 6GHz band coverage.

Most Linux kernel cycles also see new (e)BPF work and for Linux 5.18 that is the case. (e)BPF has added a packaging allocator for BPF JIT images and can lead to more efficient memory use, lower instruction TLB pressure, and other benefits. BPF also adds support for JIT'ing of add/and/or/xor/xchg atomic operations on AArch64.. There are also libbpf API improvements and a range of other enhancements.

There is also never-ending work on Linux network performance optimizations. For Linux 5.18 there are UDP IPv6 transfer optimizations, yielding up to a 5% improvement on a dummy net device. Additionally there are TSO packet size adjustments so very low latency links like those in data centers can always send full-sized TSO super-frames. Meanwhile the netns dismantling path is as much as five times faster while also having lower memory usage. Within the Intel Ethernet code is also improved AF_XDP performance.

See this pull request for the full assortment of networking updates for Linux 5.18.