Commit 70355602 authored Nov 26, 2008 by Eric Dumazet Committed by David S. Miller Nov 26, 2008

net: release skb->dst in sock_queue_rcv_skb()



When queuing a skb to sk->sk_receive_queue, we can release its dst,
not anymore needed.  Since current cpu did the dst_hold(), refcount is
probably still hot int this cpu caches.

This avoids readers to access the original dst to decrement its
refcount, possibly a long time after packet reception. This should
speedup UDP and RAW receive path.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent dd24c001

net/core/sock.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -289,7 +289,11 @@ int sock_queue_rcv_skb(struct sock sk, struct sk_buff skb)

		skb->dev = NULL;
		skb_set_owner_r(skb, sk);

		/*
		* release dst right now while its hot
		*/
		dst_release(skb->dst);
		skb->dst = NULL;
		/* Cache the SKB length before we tack it onto the receive
		* queue. Once it is added it no longer belongs to us and
		* may be freed by other threads of control pulling packets

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