The PREEMPT_RT Locking Code Is Merged For Linux 5.15

It looks like the real-time (RT) patches for the Linux kernel are almost to the point of being fully upstream in the mainline Linux kernel. Merged for Linux 5.15 is the PREEMPT_RT locking code that represents a bulk of the outstanding RT patches.

Noted earlier this month was how the PREEMPT_RT locking code appeared ready for Linux 5.15 with it being queued up as part of the "sched/core" changes. Sure enough, on the first day of this Linux 5.15 merge window the pull request was sent out and already merged by Linus Torvalds to mainline.

As noted in that prior article, the real-time upstreaming was held up due to resources/funding but over the summer we've begun to see more patches flowing. The 72 locking patches now merged for Linux 5.15 make up a large part of the remaining work but as can be seen from linux-rt-devel's patches there still is more RT work to be upstreamed.

For those not building a real-time kernel, these locking patches should have no impact on their system. More details on all the work involved with these PREEMPT_RT locking changes can be found via this pull request now part of the mainline kernel.