net: Performance fix for process_backlog

[deliverable/linux.git] / net / core / dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index 30eedf6779138d77ae9c54ca5efa8bf57587e7ac..77c19c7bb490b3fc05f658ec80a3afeeba8f5c97 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4227,9 +4227,8 @@ static int process_backlog(struct napi_struct *napi, int quota)
 #endif
        napi->weight = weight_p;
        local_irq_disable();
-       while (work < quota) {
+       while (1) {
                struct sk_buff *skb;
-               unsigned int qlen;
 
                while ((skb = __skb_dequeue(&sd->process_queue))) {
                        local_irq_enable();
@@ -4243,24 +4242,24 @@ static int process_backlog(struct napi_struct *napi, int quota)
                }
 
                rps_lock(sd);
-               qlen = skb_queue_len(&sd->input_pkt_queue);
-               if (qlen)
-                       skb_queue_splice_tail_init(&sd->input_pkt_queue,
-                                                  &sd->process_queue);
-
-               if (qlen < quota - work) {
+               if (skb_queue_empty(&sd->input_pkt_queue)) {
                        /*
                         * Inline a custom version of __napi_complete().
                         * only current cpu owns and manipulates this napi,
-                        * and NAPI_STATE_SCHED is the only possible flag set on backlog.
-                        * we can use a plain write instead of clear_bit(),
+                        * and NAPI_STATE_SCHED is the only possible flag set
+                        * on backlog.
+                        * We can use a plain write instead of clear_bit(),
                         * and we dont need an smp_mb() memory barrier.
                         */
                        list_del(&napi->poll_list);
                        napi->state = 0;
+                       rps_unlock(sd);
 
-                       quota = work + qlen;
+                       break;
                }
+
+               skb_queue_splice_tail_init(&sd->input_pkt_queue,
+                                          &sd->process_queue);
                rps_unlock(sd);
        }
        local_irq_enable();