@@ -218,10 +216,36 @@ static bool psi_update_stats(struct psi_group *group)
 	for_each_online_cpu(cpu) {
 		struct psi_group_cpu *groupc = per_cpu_ptr(group->cpus, cpu);
 		unsigned long nonidle;
+		struct rq_flags rf;
+		struct rq *rq;
+		u64 now;
 
-		if (!groupc->nonidle_time)
+		if (!groupc->nonidle_time && !groupc->nonidle)
 			continue;
 
+		/*
+		 * We come here for two things: 1) periodic per-cpu
+		 * bucket flushing and averaging and 2) when the user
+		 * wants to read a pressure file. For flushing and
+		 * averaging, which is relatively infrequent, we can
+		 * be lazy and tolerate some raciness with concurrent
+		 * updates to the per-cpu counters. However, if a user
+		 * polls the pressure state, we want to give them the
+		 * most uptodate information we have, including any
+		 * currently active state which hasn't been timed yet,
+		 * because in case of an iowait or a reclaim run, that
+		 * can be significant.
+		 */
+		if (ondemand) {
+			rq = cpu_rq(cpu);
+			rq_lock_irq(rq, &rf);