Device Memory TCP Included With The Networking Changes For Linux 6.12

Jakub Kicinski submitted the networking subsystem updates over the weekend for the Linux 6.12 merge window. Most notable this cycle is Device Memory TCP for zero-copy receive of TCP payloads to DMA-BUF regions.

Over the past year Google engineers led the work on Device Memory TCP as a means of going from the network straight to device memory such as for accelerators in a very efficient manner without having to first copy the data to a host memory buffer. This has big implications for GPUs/TPUs and other AI accelerator hardware.

The Device Memory TCP work has been maturing well and the core network code now submitted for Linux 6.12. Jakub explains in the networking pull request:

"Support Device Memory TCP, ability to zero-copy receive TCP payloads to a DMABUF region of memory while packet headers land separately in normal kernel buffers, and TCP processes then as usual."

In addition to the Device Memory TCP core support, the networking changes for Linux 6.12 also include IPv6 IOAM6 support, improving IPsec control path performance, various other performance improvements, and more.

On the network drvier side the NVIDIA Mellanox code now supports hardware-managed steering tables, the AMD Pensando driver now uses page pool to increase receive performance, there is a new driver for Realtek automotive PCIe devices such as RTL9054 / RTL9068 / RTL9072 / RTL9075 / RTL9068 / RTL9071 chipsets, EN7581 support within the MediaTek MT7530 driver, RTL8126A rev.b support within the Realtek RT8169 driver, and the Rust driver for the Applied Micro QT2025 PHY. There is also a new Motorcomm yt8821 2.5G Ethernet PHY driver, the Realtek RTW89 WiFi driver now supports the WiFi 6 chipsets of RTL8852BT and 8852BE-VT, USB 3 support in the Realtek RTW89 driver for the RTL8822CU/RTL8822BU chipsets, and various other network driver enhancements.

More details on the Linux 6.12 networking changes via this pull request.