cpumask_xor
cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
cpumask_xor(available_mask, allocated_mask, cpumask_of_node(numa_node));
cpumask_xor((struct cpumask *)dst, src1, src2);