Linux Interrupt Processing clock interrupt (ii)

The code for the

Internal_add_timer () is as follows:

static void Internal_add_timer (tvec_base_t *base, struct timer_list *timer)
{
//Timer arrival time
UN Signed Long expires = timer->expires; 　　　　
//calculation time interval
unsigned long idx = expires-base->timer_jiffies;
struct List_head *vec; 　　　　　　　　　
//According to the time interval, place the timer in the appropriate array location
if (idx < tvr_size) {
int i = expires & Tvr_mask;
VEC = Base->tv1.vec + i;
} else if (IDX < 1 << (tvr_bits + tvn_bits)) {
int i = (expires >> tvr_bits) & Tvn_mask;
Vec = Base->tv2.vec + i;
} else if (IDX < 1 << (tvr_bits + 2 * tvn_bits)) {
int i = (expires >> tvr_bits + tvn_bits)) & Tvn_mask;
Vec = Base->tv3.vec + i;
} else if (IDX < 1 << (tvr_bits + 3 * tvn_bits)) {
int i = (expires >> tvr_bits + 2 * tvn_bits)) & Tvn_mask;
Vec = Base->tv4.vec + i; 　　　　
else if (signed long idx < 0) {
/*
* Can happen if you add a timer with expires = = Jif Fies,
* or you are set a timer to go past
*/
//If interval is less than 0
Vec = Base->tv1.vec + (base->timer_jiffies & Tvr_mask); 　　　　　　　　　
} else {
int i;
　　　　　　　　　 /* If The timeout is larger than 0xFFFFFFFF in 64-bit
* Architectures Then we use the maximum timeout:
*/
//time interval is very long, set it to OXFFFFFFFF
if (idx > 0xffffffffUL) {
idx = 0xFF fffffful;
expires = idx + base->timer_jiffies; 　　　　　　　　　
}
i = (expires >> (tvr_bits + 3 * tvn_bits)) & Tvn_mask;
VEC = Base->tv5.vec + i;
}
/*
* timers are FIFO:
*/
//Add to end of list
List_add_tail (&timer->e Ntry, VEC);
}