BUG/MEDIUM: freq-ctr: Don't compute overshoot value for empty counters
The function computing the excess of events of a frequency counter over the
current period for a target frequency must handle empty counters (no event
and no start date). In this case, no excess must be reported.
Because of this bug, long pauses may be experienced on the bandwith
limitation filter.
This patch must be backported to 2.7.
diff --git a/src/freq_ctr.c b/src/freq_ctr.c
index 602ad9b..9b001e3 100644
--- a/src/freq_ctr.c
+++ b/src/freq_ctr.c
@@ -147,8 +147,9 @@
}
/* Returns the excess of events (may be negative) over the current period for
- * target frequency <freq>. It returns 0 if the counter is in the future. The
- * result considers the position of the current time within the current period.
+ * target frequency <freq>. It returns 0 if the counter is in the future or if
+ * the counter is empty. The result considers the position of the current time
+ * within the current period.
*
* The caller may safely add new events if result is negative or null.
*/
@@ -195,6 +196,11 @@
__ha_cpu_relax();
};
+ if (!curr && !tick) {
+ /* The counter is empty, there is no overshoot */
+ return 0;
+ }
+
elapsed = HA_ATOMIC_LOAD(&global_now_ms) - tick;
if (unlikely(elapsed < 0)) {
/* The counter is in the future, there is no overshoot */