4 files changed, 42 insertions, 15 deletions

diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c
index 3f7dab46626b..9b9c2ac5c4c2 100644
--- a/drivers/net/ethernet/marvell/skge.c
+++ b/drivers/net/ethernet/marvell/skge.c
@@ -3189,7 +3189,7 @@ static int skge_poll(struct napi_struct *napi, int to_do)
         if (work_done < to_do) {
                 unsigned long flags;
 
-                napi_gro_flush(napi);
+                napi_gro_flush(napi, false);
                 spin_lock_irqsave(&hw->hw_lock, flags);
                 __napi_complete(napi);
                 hw->intr_mask |= napimask[skge->port];
diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c
index 995d0cfc4c06..1c818254b7be 100644
--- a/drivers/net/ethernet/realtek/8139cp.c
+++ b/drivers/net/ethernet/realtek/8139cp.c
@@ -563,7 +563,7 @@ rx_next:
                 if (cpr16(IntrStatus) & cp_rx_intr_mask)
                         goto rx_status_loop;
 
-                napi_gro_flush(napi);
+                napi_gro_flush(napi, false);
                 spin_lock_irqsave(&cp->lock, flags);
                 __napi_complete(napi);
                 cpw16_f(IntrMask, cp_intr_mask);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a659fd0ba965..0a36fff75bd5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1497,19 +1497,22 @@ struct napi_gro_cb {
         /* This indicates where we are processing relative to skb->data. */
         int data_offset;
 
-        /* This is non-zero if the packet may be of the same flow. */
-        int same_flow;
-
         /* This is non-zero if the packet cannot be merged with the new skb. */
         int flush;
 
         /* Number of segments aggregated. */
-        int count;
+        u16     count;
+
+        /* This is non-zero if the packet may be of the same flow. */
+        u8      same_flow;
 
         /* Free the skb? */
-        int free;
+        u8      free;
 #define NAPI_GRO_FREE             1
 #define NAPI_GRO_FREE_STOLEN_HEAD 2
+
+        /* jiffies when first packet was created/queued */
+        unsigned long age;
 };
 
 #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
@@ -2156,7 +2159,7 @@ extern gro_result_t	dev_gro_receive(struct napi_struct *napi,
 extern gro_result_t     napi_skb_finish(gro_result_t ret, struct sk_buff *skb);
 extern gro_result_t     napi_gro_receive(struct napi_struct *napi,
                                          struct sk_buff *skb);
-extern void             napi_gro_flush(struct napi_struct *napi);
+extern void             napi_gro_flush(struct napi_struct *napi, bool flush_old);
 extern struct sk_buff * napi_get_frags(struct napi_struct *napi);
 extern gro_result_t     napi_frags_finish(struct napi_struct *napi,
                                           struct sk_buff *skb,
diff --git a/net/core/dev.c b/net/core/dev.c
index de2bad717d56..d44668f63c88 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3471,17 +3471,31 @@ out:
         return netif_receive_skb(skb);
 }
 
-inline void napi_gro_flush(struct napi_struct *napi)
+/* napi->gro_list contains packets ordered by age.
+ * youngest packets at the head of it.
+ * Complete skbs in reverse order to reduce latencies.
+ */
+void napi_gro_flush(struct napi_struct *napi, bool flush_old)
 {
-        struct sk_buff *skb, *next;
+        struct sk_buff *skb, *prev = NULL;
 
-        for (skb = napi->gro_list; skb; skb = next) {
-                next = skb->next;
+        /* scan list and build reverse chain */
+        for (skb = napi->gro_list; skb != NULL; skb = skb->next) {
+                skb->prev = prev;
+                prev = skb;
+        }
+
+        for (skb = prev; skb; skb = prev) {
                 skb->next = NULL;
+
+                if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
+                        return;
+
+                prev = skb->prev;
                 napi_gro_complete(skb);
+                napi->gro_count--;
         }
 
-        napi->gro_count = 0;
         napi->gro_list = NULL;
 }
 EXPORT_SYMBOL(napi_gro_flush);
@@ -3542,6 +3556,7 @@ enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
 
         napi->gro_count++;
         NAPI_GRO_CB(skb)->count = 1;
+        NAPI_GRO_CB(skb)->age = jiffies;
         skb_shinfo(skb)->gso_size = skb_gro_len(skb);
         skb->next = napi->gro_list;
         napi->gro_list = skb;
@@ -3878,7 +3893,7 @@ void napi_complete(struct napi_struct *n)
         if (unlikely(test_bit(NAPI_STATE_NPSVC, &n->state)))
                 return;
 
-        napi_gro_flush(n);
+        napi_gro_flush(n, false);
         local_irq_save(flags);
         __napi_complete(n);
         local_irq_restore(flags);
@@ -3983,8 +3998,17 @@ static void net_rx_action(struct softirq_action *h)
                                 local_irq_enable();
                                 napi_complete(n);
                                 local_irq_disable();
-                        } else
+                        } else {
+                                if (n->gro_list) {
+                                        /* flush too old packets
+                                         * If HZ < 1000, flush all packets.
+                                         */
+                                        local_irq_enable();
+                                        napi_gro_flush(n, HZ >= 1000);
+                                        local_irq_disable();
+                                }
                                 list_move_tail(&n->poll_list, &sd->poll_list);
+                        }
                 }
 
                 netpoll_poll_unlock(have);