}
}
-
-/*
- * Get the preferred target CPU for NOHZ
- */
-static int hrtimer_get_target(int this_cpu, int pinned)
-{
-#ifdef CONFIG_NO_HZ_COMMON
- if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
- return get_nohz_timer_target();
-#endif
- return this_cpu;
-}
-
/*
* With HIGHRES=y we do not migrate the timer when it is expiring
* before the next event on the target cpu because we cannot reprogram
struct hrtimer_clock_base *new_base;
struct hrtimer_cpu_base *new_cpu_base;
int this_cpu = smp_processor_id();
- int cpu = hrtimer_get_target(this_cpu, pinned);
+ int cpu = get_nohz_timer_target(pinned);
int basenum = base->index;
again:
goto again;
}
timer->base = new_base;
+ } else {
+ if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
+ cpu = this_cpu;
+ goto again;
+ }
}
return new_base;
}
cpu_base->expires_next.tv64 = expires_next.tv64;
+ /*
+ * If a hang was detected in the last timer interrupt then we
+ * leave the hang delay active in the hardware. We want the
+ * system to make progress. That also prevents the following
+ * scenario:
+ * T1 expires 50ms from now
+ * T2 expires 5s from now
+ *
+ * T1 is removed, so this code is called and would reprogram
+ * the hardware to 5s from now. Any hrtimer_start after that
+ * will not reprogram the hardware due to hang_detected being
+ * set. So we'd effectivly block all timers until the T2 event
+ * fires.
+ */
+ if (cpu_base->hang_detected)
+ return;
+
if (cpu_base->expires_next.tv64 != KTIME_MAX)
tick_program_event(cpu_base->expires_next, 1);
}