Updated Printk Rework Patches - Necessary Step For Mainlining Linux Real-Time "RT"

John Ogness of Linutronix today sent out the second iteration of his patches working on threaded printing support for printk() and related rework of that code that is a necessary step before the real-time (RT) kernel patches can be finally mainlined.

This threaded printing / atomic consoles support as part of non-blocking consoles has been the last major blocker before the real-time kernel patches can be finally mainlined. These printk code changes though have been slow in getting over the finish line for un-blocking the RT mainlining.

Ogness explained in today's v2 patch series:

"This is v2 of a series to implement threaded console printing as well as some other minor pieces (such as proc and sysfs support). This series is only a subset of the original v1. In particular, this series represents patches 11, 12, 15 of the v1 series. For information about the motivation of the nbcon consoles, please read the cover letter of v1.

This series provides the remaining pieces of the printk rework. All other components are either already mainline or are currently in linux-next. In particular this series does:

- Implement dedicated printing threads per nbcon console.

- Implement "threadprintk" boot argument to force threading of legacy consoles.

- Implement nbcon support for proc and sysfs console-related files.

- Provide a new helper function nbcon_reacquire() to allow nbcon console drivers to reacquire ownership.

Note that this series does *not* provide an nbcon console driver. That will come in a follow-up series."

With the other patches in linux-next gives them good chances of in turn making it into the Linux 6.11 kernel. We'll see if all of this work and pushing the real-time (PREEMPT_RT) support to mainline can finally happen in 2024.

See today's v2 patch series for those interested in the threaded printing work itself.