/proc/interrupts

cat /proc/interrupts 

读取到的内容从左到右，分别为：1、逻辑中断号，2、中断在各CPU发生的次数，3、中断所属设备类名称，4、硬件中断号，5、中断处理函数。

如下图：

代码实现分析如下红色字体1～ 5 . 

489  int show_interrupts(struct seq_file *p, void *v)
490  {
491  	static int prec;
492  
493  	unsigned long flags, any_count = 0;
494  	int i = *(loff_t *) v, j;
495  	struct irqaction *action;
496  	struct irq_desc *desc;
497  
498  	if (i > ACTUAL_NR_IRQS)
499  		return 0;
500  
501  	if (i == ACTUAL_NR_IRQS)
502  		return arch_show_interrupts(p, prec);
503 
504  	/* print header and calculate the width of the first column */   
505  	if (i == 0) {
506  		for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
507  			j *= 10;
508  
509  		seq_printf(p, "%*s", prec + 8, "");
510  		for_each_online_cpu(j)
511  			seq_printf(p, "CPU%-8d", j);
512  		seq_putc(p, '\n');
513  	}
514  
515  	irq_lock_sparse();
516  	desc = irq_to_desc(i);
517  	if (!desc)
518  		goto outsparse;
519  
520  	raw_spin_lock_irqsave(&desc->lock, flags);
521  	for_each_online_cpu(j)
522  		any_count |= kstat_irqs_cpu(i, j);
523  	action = desc->action;
524  	if (!action && !any_count)
525  		goto out;
526  
527  	seq_printf(p, "%*d: ", prec, i);     //1、打印逻辑中断号

528  	for_each_online_cpu(j)
529  		seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));    //2、打印中断次数
530  
531  	if (desc->irq_data.chip) {
532  		if (desc->irq_data.chip->irq_print_chip)
533  			desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
534  		else if (desc->irq_data.chip->name)
535  			seq_printf(p, " %8s", desc->irq_data.chip->name);   //3、打印中断名称
536  		else
537  			seq_printf(p, " %8s", "-");
538  	} else {
539  		seq_printf(p, " %8s", "None");
540  	}
541  	if (desc->irq_data.domain)
542  		seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);        //4、打印硬件中断号，比如，gpio number 
543  #ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
544  	seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");  //打印中断触发类型
545  #endif
546  	if (desc->name)
547  		seq_printf(p, "-%-8s", desc->name);
548  
549  	if (action) {
550  		seq_printf(p, "  %s", action->name);
551  		while ((action = action->next) != NULL)
552  			seq_printf(p, ", %s", action->name);    //5、打印中断处理函数名称
553  	}
554  
555  	seq_putc(p, '\n');
556  out:
557  	raw_spin_unlock_irqrestore(&desc->lock, flags);
558  outsparse:
559  	irq_unlock_sparse();
560  	return 0;
561  }
562