+ if (now > group->polling_until) {
+ /*
+ * We are either about to start or might stop polling if no
+ * state change was recorded. Resetting poll_scheduled leaves
+ * a small window for psi_group_change to sneak in and schedule
+ * an immediate poll_work before we get to rescheduling. One
+ * potential extra wakeup at the end of the polling window
+ * should be negligible and polling_next_update still keeps
+ * updates correctly on schedule.
+ */
+ atomic_set(&group->poll_scheduled, 0);
+ /*
+ * A task change can race with the poll worker that is supposed to
+ * report on it. To avoid missing events, ensure ordering between
+ * poll_scheduled and the task state accesses, such that if the poll
+ * worker misses the state update, the task change is guaranteed to
+ * reschedule the poll worker:
+ *
+ * poll worker:
+ * atomic_set(poll_scheduled, 0)
+ * smp_mb()
+ * LOAD states
+ *
+ * task change:
+ * STORE states
+ * if atomic_xchg(poll_scheduled, 1) == 0:
+ * schedule poll worker
+ *
+ * The atomic_xchg() implies a full barrier.
+ */
+ smp_mb();
+ } else {
+ /* Polling window is not over, keep rescheduling */
+ force_reschedule = true;
+ }
+
+