diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4b55ab2bedf5b1c7f09914ba3e37d936750f0e8f..1a110ea94335938b7a06bb428cc9c77308352513 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1297,15 +1297,21 @@ static void packet_sock_destruct(struct sock *sk)
 
 static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
 {
-	u32 rxhash;
+	u32 *history = po->rollover->history;
+	u32 victim, rxhash;
 	int i, count = 0;
 
 	rxhash = skb_get_hash(skb);
 	for (i = 0; i < ROLLOVER_HLEN; i++)
-		if (po->rollover->history[i] == rxhash)
+		if (READ_ONCE(history[i]) == rxhash)
 			count++;
 
-	po->rollover->history[prandom_u32() % ROLLOVER_HLEN] = rxhash;
+	victim = prandom_u32() % ROLLOVER_HLEN;
+
+	/* Avoid dirtying the cache line if possible */
+	if (READ_ONCE(history[victim]) != rxhash)
+		WRITE_ONCE(history[victim], rxhash);
+
 	return count > (ROLLOVER_HLEN >> 1);
 }