Improving the Linux kernel with upstream contributions

This post details Meta's upstream-first philosophy for Linux kernel development, contributing changes to the mainline kernel before internal deployment. Specific contributions include: improvements to blk-mq for block layer queuing, stabilization of Btrfs with over 50 changes, implementation of the New Vegas congestion control algorithm, writeback support for cgroups to enable IO limiting, advancements in network virtualization (GUE, IPv6 flow label, ILA), IPv6 performance improvements to scale the routing tree, a caching layer for MD RAID 5/6 to address the write hole and improve performance, and progress in release engineering for faster kernel deployment.