* is used on S/390 to stop all activity when a cpus is idle.
* This functions needs to be called disabled.
*/
-unsigned long next_timer_interrupt(void)
+static unsigned long __next_timer_interrupt(tvec_base_t *base)
{
- tvec_base_t *base;
- struct list_head *list;
+ unsigned long timer_jiffies = base->timer_jiffies;
+ unsigned long expires = timer_jiffies + (LONG_MAX >> 1);
+ int index, slot, array, found = 0;
struct timer_list *nte;
- unsigned long expires;
- unsigned long hr_expires = MAX_JIFFY_OFFSET;
- ktime_t hr_delta;
tvec_t *varray[4];
- int i, j;
-
- hr_delta = hrtimer_get_next_event();
- if (hr_delta.tv64 != KTIME_MAX) {
- struct timespec tsdelta;
- tsdelta = ktime_to_timespec(hr_delta);
- hr_expires = timespec_to_jiffies(&tsdelta);
- if (hr_expires < 3)
- return hr_expires + jiffies;
- }
- hr_expires += jiffies;
-
- base = __get_cpu_var(tvec_bases);
- spin_lock(&base->lock);
- expires = base->timer_jiffies + (LONG_MAX >> 1);
- list = NULL;
/* Look for timer events in tv1. */
- j = base->timer_jiffies & TVR_MASK;
+ index = slot = timer_jiffies & TVR_MASK;
do {
- list_for_each_entry(nte, base->tv1.vec + j, entry) {
+ list_for_each_entry(nte, base->tv1.vec + slot, entry) {
+ found = 1;
expires = nte->expires;
- if (j < (base->timer_jiffies & TVR_MASK))
- list = base->tv2.vec + (INDEX(0));
- goto found;
+ /* Look at the cascade bucket(s)? */
+ if (!index || slot < index)
+ goto cascade;
+ return expires;
}
- j = (j + 1) & TVR_MASK;
- } while (j != (base->timer_jiffies & TVR_MASK));
+ slot = (slot + 1) & TVR_MASK;
+ } while (slot != index);
+
+cascade:
+ /* Calculate the next cascade event */
+ if (index)
+ timer_jiffies += TVR_SIZE - index;
+ timer_jiffies >>= TVR_BITS;
/* Check tv2-tv5. */
varray[0] = &base->tv2;
varray[1] = &base->tv3;
varray[2] = &base->tv4;
varray[3] = &base->tv5;
- for (i = 0; i < 4; i++) {
- j = INDEX(i);
+
+ for (array = 0; array < 4; array++) {
+ tvec_t *varp = varray[array];
+
+ index = slot = timer_jiffies & TVN_MASK;
do {
- if (list_empty(varray[i]->vec + j)) {
- j = (j + 1) & TVN_MASK;
- continue;
- }
- list_for_each_entry(nte, varray[i]->vec + j, entry)
+ list_for_each_entry(nte, varp->vec + slot, entry) {
+ found = 1;
if (time_before(nte->expires, expires))
expires = nte->expires;
- if (j < (INDEX(i)) && i < 3)
- list = varray[i + 1]->vec + (INDEX(i + 1));
- goto found;
- } while (j != (INDEX(i)));
- }
-found:
- if (list) {
- /*
- * The search wrapped. We need to look at the next list
- * from next tv element that would cascade into tv element
- * where we found the timer element.
- */
- list_for_each_entry(nte, list, entry) {
- if (time_before(nte->expires, expires))
- expires = nte->expires;
- }
+ }
+ /*
+ * Do we still search for the first timer or are
+ * we looking up the cascade buckets ?
+ */
+ if (found) {
+ /* Look at the cascade bucket(s)? */
+ if (!index || slot < index)
+ break;
+ return expires;
+ }
+ slot = (slot + 1) & TVN_MASK;
+ } while (slot != index);
+
+ if (index)
+ timer_jiffies += TVN_SIZE - index;
+ timer_jiffies >>= TVN_BITS;
}
- spin_unlock(&base->lock);
+ return expires;
+}
- /*
- * It can happen that other CPUs service timer IRQs and increment
- * jiffies, but we have not yet got a local timer tick to process
- * the timer wheels. In that case, the expiry time can be before
- * jiffies, but since the high-resolution timer here is relative to
- * jiffies, the default expression when high-resolution timers are
- * not active,
- *
- * time_before(MAX_JIFFY_OFFSET + jiffies, expires)
- *
- * would falsely evaluate to true. If that is the case, just
- * return jiffies so that we can immediately fire the local timer
- */
- if (time_before(expires, jiffies))
- return jiffies;
+/*
+ * Check, if the next hrtimer event is before the next timer wheel
+ * event:
+ */
+static unsigned long cmp_next_hrtimer_event(unsigned long now,
+ unsigned long expires)
+{
+ ktime_t hr_delta = hrtimer_get_next_event();
+ struct timespec tsdelta;
- if (time_before(hr_expires, expires))
- return hr_expires;
+ if (hr_delta.tv64 == KTIME_MAX)
+ return expires;
+ if (hr_delta.tv64 <= TICK_NSEC)
+ return now;
+
+ tsdelta = ktime_to_timespec(hr_delta);
+ now += timespec_to_jiffies(&tsdelta);
+ if (time_before(now, expires))
+ return now;
return expires;
}
+
+/**
+ * next_timer_interrupt - return the jiffy of the next pending timer
+ */
+unsigned long next_timer_interrupt(void)
+{
+ tvec_base_t *base = __get_cpu_var(tvec_bases);
+ unsigned long expires, now = jiffies;
+
+ spin_lock(&base->lock);
+ expires = __next_timer_interrupt(base);
+ spin_unlock(&base->lock);
+
+ if (time_before_eq(expires, now))
+ return now;
+
+ return cmp_next_hrtimer_event(now, expires);
+}
#endif
/******************************************************************/
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / blobdiff