KSE terminology in the comments for cpu_set_upcall_kse() confuses much more than explains.
Remove two XXX in kern_thread.c. One is probably rotten as is, another one required better formulation.
Remove code duplication in weed_inhib().
The question: does it make sense to rename cpu_set_upcall_kse() ? I stopped there. Good name could be e.g. cpu_set_userret().