packet: rollover huge flows before small flows

[cascardo/linux.git] / net / packet / af_packet.c

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 3a383fd..8f0156b 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1341,6 +1341,20 @@ static int fanout_rr_next(struct packet_fanout *f, unsigned int num)
        return x;
 }
 
+static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
+{
+       u32 rxhash;
+       int i, count = 0;
+
+       rxhash = skb_get_hash(skb);
+       for (i = 0; i < ROLLOVER_HLEN; i++)
+               if (po->rollover->history[i] == rxhash)
+                       count++;
+
+       po->rollover->history[prandom_u32() % ROLLOVER_HLEN] = rxhash;
+       return count > (ROLLOVER_HLEN >> 1);
+}
+
 static unsigned int fanout_demux_hash(struct packet_fanout *f,
                                      struct sk_buff *skb,
                                      unsigned int num)
@@ -1381,11 +1395,16 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f,
                                          unsigned int num)
 {
        struct packet_sock *po, *po_next;
-       unsigned int i, j;
+       unsigned int i, j, room;
 
        po = pkt_sk(f->arr[idx]);
-       if (try_self && packet_rcv_has_room(po, skb) != ROOM_NONE)
-               return idx;
+
+       if (try_self) {
+               room = packet_rcv_has_room(po, skb);
+               if (room == ROOM_NORMAL ||
+                   (room == ROOM_LOW && !fanout_flow_is_huge(po, skb)))
+                       return idx;
+       }
 
        i = j = min_t(int, po->rollover->sock, num - 1);
        do {