android - 如何在 linux 内核中定义和触发我自己的新 softirq？

Question

我想在 linux 内核中创建我自己的 softirq。这是正确的做法吗:

在模块的 init 中，我想触发 softirq，我将添加一个调用:

394 void open_softirq(int nr, void (*action)(struct softirq_action *))
395 {
396         softirq_vec[nr].action = action;
397 }

在我想引发软中断的代码 fragment 中，我将添加对 raise_softirq 函数的调用:

379 void raise_softirq(unsigned int nr)
380 {
381         unsigned long flags;
382 
383         local_irq_save(flags);
384         raise_softirq_irqoff(nr);
385         local_irq_restore(flags);
386 }

并将我的新softirq添加到:

411 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
412    frequency threaded job scheduling. For almost all the purposes
413    tasklets are more than enough. F.e. all serial device BHs et
414    al. should be converted to tasklets, not to softirqs.
415  */
416 
417 enum
418 {
419         HI_SOFTIRQ=0,
420         TIMER_SOFTIRQ,
421         NET_TX_SOFTIRQ,
422         NET_RX_SOFTIRQ,
423         BLOCK_SOFTIRQ,
424         BLOCK_IOPOLL_SOFTIRQ,
425         TASKLET_SOFTIRQ,
426         SCHED_SOFTIRQ,
427         HRTIMER_SOFTIRQ,
428         RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
429         MY_NEW_SOFTIRQ
430         NR_SOFTIRQS
431 };

在这里:

 60 char *softirq_to_name[NR_SOFTIRQS] = {
 61         "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
 62         "TASKLET", "SCHED", "HRTIMER", "RCU", "MY_NEW_SOFTIRQ"
 63 };

问题:

• 我是对的还是我漏掉了什么？
• 这样做正确吗？还有其他选择吗？

Answer 1

如果您想修补内核并重新编译它，您可能做对了(除非您应该将它移到 RCU_SOFTIRQ 之前)。

否则，如果您想在内核模块中执行 IOW，则必须使用基于 SoftIRQ 的 tasklet 在 SoftIRQ 上下文中执行某些操作:

tasklet_init() 用于初始化您的钩子(Hook)。

tasklet_schedule() 调度您注册的 tasklet。