net: batch skb dequeueing from softnet input_pkt_queue

batch skb dequeueing from softnet input_pkt_queue to reduce potential lock
contention when RPS is enabled.

Note: in the worst case, the number of packets in a softnet_data may
be double of netdev_max_backlog.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c04ca246395d..40d4c20d034b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1388,6 +1388,7 @@ struct softnet_data {
         struct Qdisc            **output_queue_tailp;
         struct list_head        poll_list;
         struct sk_buff          *completion_queue;
+        struct sk_buff_head     process_queue;
 
 #ifdef CONFIG_RPS
         struct softnet_data     *rps_ipi_list;
@@ -1402,10 +1403,11 @@ struct softnet_data {
         struct napi_struct      backlog;
 };
 
-static inline void input_queue_head_incr(struct softnet_data *sd)
+static inline void input_queue_head_add(struct softnet_data *sd,
+                                        unsigned int len)
 {
 #ifdef CONFIG_RPS
-        sd->input_queue_head++;
+        sd->input_queue_head += len;
 #endif
 }