Hi all,

I've been doing some reading on the OpenBSD kernel and found out that
the kernel is non-premeptible. So, if a process is running in kernel
mode, it can never be pre-empted unless it voluntarily calls tsleep() or
it returns to user space. Since, it is the timer interrupt handler that
calculates process run times and calls schedule() if some process
exceeded its time limit, how does it know not to do a schedule() if the
current process is in kernel mode? How can it know if the current
process is in user mode or kernel mode?

Regards,
Bijoy.