On Tue, 8 Apr 2025, Paul E. McKenney wrote: > RCU handles this by iterating from zero to nr_cpu_ids, which is set during > early boot. It also builds its tree-shaped data structures during early > boot based on nr_cpu_ids.
nr_cpu_ids is better but there are funky things like the default bios of a major server vendor indicating 256 or so possible cpus although only 2 were installed. Thus nr_cpu_id is 256. Presumably some hardware configurations can support onlining 256 cpus....
