Prompt the account Scheduling O(1)

Hello!  E xcuse me for my english. I study source code scheduler O(1) code : if (hardirq_count())                 per_cpu(cpu_hardirq_time, cpu) +=delta; else if (in_serving_softirq() && !(curr->flags & PF_KSOFTIRQD))                 per_cpu(cpu_softirq_time, cpu) +=delta; question: tell me what 's going on here ? I have this code in paper form , so I can not give you a link to the code . If there is a need to rewrite your page please help !