More RT Code Out For Review, RT Patches Updated Against Linux 5.14

The real-time (RT) patches for the Linux kernel still appear a ways off from mainline but at least there is movement on this important patch series for embedded and other use-cases needing real-time support.

While mainlining the long out-of-tree Linux "RT" patches has been brought up many times in recent years, earlier this year the developers noted the mainlining has been held up by a lack of funding in getting the patches across the finish line. The PREEMPT_RT "development and maintenance is currently stalled" at least as was the case earlier this year but does seem to be loosening up a bit now.

Following last month's RT rebasing to Linux 5.13, the first RT patches against the current Linux 5.14 development code has been published. v5.14-rc3-rt1 was posted on Friday. The real-time patches were re-based against the Linux 5.14 development state, the locking code saw some updates, some SLUB code was also updated, MEMCG support was disabled, and some ARM64 fixes also incorporated.

Also on Friday a set of 63 patches around the PREEMPT-RT locking infrastructure was posted for review. This represents most of RT's locking code. These patches shouldn't affect non-RT kernel behavior but still need to go through an extensive review before mainlining. This is also just a portion of the overall RT work with no clear indication yet when the entire patch series may go into the mainline tree.