net: don't bother calling list RX functions on empty lists
Generally the check should be very cheap, as the sk_buff_head is in cache.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 5e22719..7e6a2f6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4887,7 +4887,8 @@ static void __netif_receive_skb_list(struct list_head *head)
/* Handle the previous sublist */
list_cut_before(&sublist, head, &skb->list);
- __netif_receive_skb_list_core(&sublist, pfmemalloc);
+ if (!list_empty(&sublist))
+ __netif_receive_skb_list_core(&sublist, pfmemalloc);
pfmemalloc = !pfmemalloc;
/* See comments in __netif_receive_skb */
if (pfmemalloc)
@@ -4897,7 +4898,8 @@ static void __netif_receive_skb_list(struct list_head *head)
}
}
/* Handle the remaining sublist */
- __netif_receive_skb_list_core(head, pfmemalloc);
+ if (!list_empty(head))
+ __netif_receive_skb_list_core(head, pfmemalloc);
/* Restore pflags */
if (pfmemalloc)
memalloc_noreclaim_restore(noreclaim_flag);
@@ -5058,6 +5060,8 @@ void netif_receive_skb_list(struct list_head *head)
{
struct sk_buff *skb;
+ if (list_empty(head))
+ return;
list_for_each_entry(skb, head, list)
trace_netif_receive_skb_list_entry(skb);
netif_receive_skb_list_internal(head);