cpumask_nth
ctx->cb_cpu = cpumask_nth(cpu_index, cpu_online_mask);
curr_cpu = cpumask_nth(possible / ht, &node_affinity.real_cpu_mask) + 1;
curr_cpu = cpumask_nth(num_cores * node_affinity.num_online_nodes, hw_thread_mask) + 1;
cpu = *stored_cpu = cpumask_nth(id % num_online_cpus(), cpu_online_mask);
*cb_cpu = cpumask_nth(cpu_index, pd->cpumask.cbcpu);
return cpumask_nth(cpu_index, pd->cpumask.pcpu);
cpumask_nth(1, mask) >= nr_cpu_ids;
cpumask_nth(1, mask) < nr_cpu_ids;