FreeBSD Hot Swap kernel upgrade & run-time switching without reboot.
From BSDCan 2012 Talk summary:
- Linux has the ability to quickly reboot a system by loading a new kernel image into memory while they system is running and then restart into the new kernel bypassing the reset bios post process.
- By utilizing the excellent work already done in the loader userboot.so project kload (kernel loader) provides must of the same functionality as kexec. Kload load a new kernel image into temporary kernel space prior to shutdown / reboot. The final step of reboot it then changed to overwrite the existing kernel image with the new image currently in temporary space, and jump to the new start address.
- This process bypasses the entire bios cycle and slow bios disk reads.
- Overall time saving varies based each bios cycle time.
- Driver testing