If new callout scheduled to another CPU and we are using global timer,

there is high probability that timer is already programmed by some other
CPU. Especially by one that registered this callout, and so active now.

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/kern/kern_clocksource.c b/sys/kern/kern_clocksource.c
index 455564b..e9a7c9d 100644
--- a/sys/kern/kern_clocksource.c
+++ b/sys/kern/kern_clocksource.c
@@ -785,14 +785,18 @@ cpu_new_callout(int cpu, int ticks)
 	}
 	/*
 	 * If timer is periodic - just update next event time for target CPU.
+	 * If timer is global - there is chance it is already programmed.
 	 */
-	if (periodic) {
+	if (periodic || (timer->et_flags & ET_FLAGS_PERCPU) == 0) {
 		state->nextevent = state->nexthard;
 		tmp = hardperiod;
 		bintime_mul(&tmp, ticks - 1);
 		bintime_add(&state->nextevent, &tmp);
-		ET_HW_UNLOCK(state);
-		return;
+		if (periodic ||
+		    bintime_cmp(&state->nextevent, &nexttick, >=)) {
+			ET_HW_UNLOCK(state);
+			return;
+		}
 	}
 	/*
 	 * Otherwise we have to wake that CPU up, as we can't get present