linux tasklet

http://blog.chinaunix.net/u/24474/showart_227121.html
Çý¶¯³ÌÐòʹÓÃtasklet»úÖÆ
ת×Ô£ºhttp://blog.chinaunix.net/u/15169/showart.php?id=82989
Çý
¶¯³ÌÐòÔÚ³õʼ»¯Ê±£¬Í¨¹ýº¯Êýtask_init½¨Á¢Ò»¸ötasklet£¬È»ºóµ÷Óú¯Êýtasklet_schedule½«Õâ¸ötasklet·ÅÔÚ
tasklet_vecÁ´±íµÄÍ·²¿£¬²¢»½ÐѺǫ́Ïß³Ìksoftirqd¡£µ±ºǫ́Ïß³ÌksoftirqdÔËÐе÷ÓÃ__do_softirqʱ£¬»áÖ´ÐÐÔÚÖжÏ
ÏòÁ¿±ísoftirq_vecÀïÖжϺÅTASKLET_SOFTIRQ¶ÔÓ¦µÄtasklet_actionº¯Êý£¬È»ºótasklet_action±éÀú
tasklet_vecÁ´±í£¬µ÷ÓÃÿ¸ötaskletµÄº¯ÊýÍê³ÉÈíÖжϲÙ×÷¡£
 
ÏÂÃæ¶Ôº¯Êýtasklet_initºÍtasklet_schedule·ÖÎö£º
   º¯Êýtasklet_init³õʼ»¯Ò»¸ötasklet,Æä²ÎÊýtÊÇtasklet_struct½á¹¹ÃèÊöµÄtasklet,²ÎÊý(*func)ÊÇÈíÖжÏÏìÓ¦º¯Êý¡£
void tasklet_init(struct tasklet_struct *t,
    void (*func)(unsigned long), unsigned long data)
{
 t->next = NULL;
 t->state = 0;
 atomic_set(&t->count, 0);
 t->func = func;
 t->data = data;
}
Çý¶¯³ÌÐòµ÷Óú¯Êýtasklet_scheduleÀ´ÔËÐÐtasklet¡£
static inline void tasklet_schedule(struct tasklet_struct *t)
{
 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
  __tasklet_schedule(t);
}
º¯Êý__tasklet_scheduleµÃµ½µ±Ç°CPUµÄtasklet_vecÁ´±í£¬²¢Ö´ÐÐTASKLET_SOFTIRQÈíÖжϡ£
void fastcall __tasklet_schedule(struct tasklet_struct *t)
{
 unsigned long flags;
 local_irq_save(flags);
 t->next = __get_cpu_var(tasklet_vec).list;
 __get_cpu_var(tasklet_vec).list = t;
 raise_softirq_irqoff(TASKLET_SOFTIRQ);
 local_irq_restore(flags);
}
º¯Êýraise_softirq_irqoffÉèÖÃÈíÖжÏnrΪ¹ÒÆð״̬£¬²¢ÔÚûÓÐÖжÏʱ»½ÐÑÏß³Ìksoftirqd¡£º¯Êýraise_softirq_irqoff±ØÐëÔÚ¹ØÖжÏÇé¿öÏÂÔËÐС£
inline fastcall void raise_softirq_irqoff(unsigned int nr)
{
 __raise_softirq_irqoff(nr);
 /*
  * If we're in an interrupt or softirq, we're done
  * (this also catches softirq-disabled code). We will
  * actually run the softirq once we return from
  * the irq or softirq.
  *
  *