net_sched: sfb: optimize enqueue on full queue

In case SFB queue is full (hard limit reached), there is no point
spending time to compute hash and maximum qlen/p_mark.

We instead just early drop packet.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 5 deletions

diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c
index 0a833d0c1f61..e83c272c0325 100644
--- a/net/sched/sch_sfb.c
+++ b/net/sched/sch_sfb.c
@@ -287,6 +287,12 @@ static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
         u32 r, slot, salt, sfbhash;
         int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 
+        if (unlikely(sch->q.qlen >= q->limit)) {
+                sch->qstats.overlimits++;
+                q->stats.queuedrop++;
+                goto drop;
+        }
+
         if (q->rehash_interval > 0) {
                 unsigned long limit = q->rehash_time + q->rehash_interval;
 
@@ -332,12 +338,9 @@ static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
         slot ^= 1;
         sfb_skb_cb(skb)->hashes[slot] = 0;
 
-        if (unlikely(minqlen >= q->max || sch->q.qlen >= q->limit)) {
+        if (unlikely(minqlen >= q->max)) {
                 sch->qstats.overlimits++;
-                if (minqlen >= q->max)
-                        q->stats.bucketdrop++;
-                else
-                        q->stats.queuedrop++;
+                q->stats.bucketdrop++;
                 goto drop;
         }