The 5.15 merge window is off to a fast start; stay tuned for our usual full
summary. It is worth mentioning, though, that the realtime preemption
locking code has been pulled into the
mainline with little fanfare. This
work began in 2004 and has fundamentally
changed many parts of the core kernel. With this pull, the sleepable locks
that make deterministic realtime response possible have finally joined all
of that other work (though the kernel must be built with the
REALTIME configuration option to use them).
Congratulations are due to all of the realtime developers who pushed this
project forward for nearly two decades.