On 2017年01月01日 01:31, David Miller wrote:
From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Fri, 30 Dec 2016 13:20:51 +0800
@@ -1283,10 +1314,15 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
skb_probe_transport_header(skb, 0);
rxhash = skb_get_hash(skb);
+
#ifndef CONFIG_4KSTACKS
- local_bh_disable();
- netif_receive_skb(skb);
- local_bh_enable();
+ if (!rx_batched) {
+ local_bh_disable();
+ netif_receive_skb(skb);
+ local_bh_enable();
+ } else {
+ tun_rx_batched(tfile, skb, more);
+ }
#else
netif_rx_ni(skb);
#endif
If rx_batched has been set, and we are talking to clients not using
this new MSG_MORE facility (or such clients don't have multiple TX
packets to send to you, thus MSG_MORE is often clear), you are doing a
lot more work per-packet than the existing code.
You take the queue lock, you test state, you splice into a local queue
on the stack, then you walk that local stack queue to submit just one
SKB to netif_receive_skb().
I think you want to streamline this sequence in such cases so that the
cost before and after is similar if not equivalent.
Yes, so I will do a skb_queue_empty() check if !MSG_MORE and call
netif_receive_skb() immediately in this case. This can save the wasted
efforts.
Thanks
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