---

yaml
---
r: 191012
b: refs/heads/master
c: 77e38ed
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d14aada8e20bdf81ffd43f433b123972cf575b32
+refs/heads/master: 77e38ed347162423c6b72e06c865a121081c2bb6

trunk/kernel/rcutree_plugin.h

@@ -1051,19 +1051,27 @@ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff);
 int rcu_needs_cpu(int cpu)
 {
 	int c = 0;
+	int snap;
+	int snap_nmi;
 	int thatcpu;
 
 	/* Check for being in the holdoff period. */
 	if (per_cpu(rcu_dyntick_holdoff, cpu) == jiffies)
 		return rcu_needs_cpu_quick_check(cpu);
 
 	/* Don't bother unless we are the last non-dyntick-idle CPU. */
-	for_each_cpu_not(thatcpu, nohz_cpu_mask)
-		if (cpu_online(thatcpu) && thatcpu != cpu) {
+	for_each_online_cpu(thatcpu) {
+		if (thatcpu == cpu)
+			continue;
+		snap = per_cpu(rcu_dynticks, thatcpu)->dynticks;
+		snap_nmi = per_cpu(rcu_dynticks, thatcpu)->dynticks_nmi;
+		smp_mb(); /* Order sampling of snap with end of grace period. */
+		if (((snap & 0x1) != 0) || ((snap_nmi & 0x1) != 0)) {
 			per_cpu(rcu_dyntick_drain, cpu) = 0;
 			per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
 			return rcu_needs_cpu_quick_check(cpu);
 		}
+	}
 
 	/* Check and update the rcu_dyntick_drain sequencing. */
 	if (per_cpu(rcu_dyntick_drain, cpu) <= 0) {