Fast Kernel Headers Work Restarted For Linux To Ultimately Speed Up Build Times

Posted at the start of 2022 was a set of 2.3k patches dubbed "fast kernel headers" to massively speed-up build times for compiling the kernel and to address dependency hell situations. While it was quick to iterate at first and some bits got upstreamed, it's been months since hearing anything new on the fast kernel headers topic. But today a new patch series was posted that's restarting the effort in working towards massively speeding up kernel build times.

Max Kellermann posted a set of 28 patches today that are working to retake on the fast kernel headers effort. The initial patches are working on reducing various kernel header dependencies. Various initial prep work is in this patch series, which by itself isn't leading to any magnificent build time improvements. Max noted:

"Just like the other attempts to reduce header dependencies in the past, this is just the beginning. There are still too many dependencies, and the speedup gained by this large patch set is not yet impressive.
...
For more gains, huge headers like "linux/mm.h", "linux/fs.h" and "linux/sched.h" would need to be optimized. Nearly everybody includes them, and they include nearly everything."

Those interested can see today's patch series while hopefully the more fruitful fast kernel headers optimizations will come about soon.