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af_packet: Avoid cache line dirtying

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While doing multiple captures, I found af_packet was dirtying cache line
containing its prot_hook.

This slow down machines where several cpus are necessary to handle capture
traffic, as each prot_hook is traversed for each packet coming in or out
the host.

This patches moves "struct packet_type prot_hook" to the end of
packet_sock, and uses a ____cacheline_aligned_in_smp to make sure
this remains shared by all cpus.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2009-10-16 04:02:20 +00:00 committed by David S. Miller
parent 7b6856a029
commit 94b059520d
1 changed files with 1 additions and 1 deletions
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2
net/packet/af_packet.c
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@ -188,7 +188,6 @@ struct packet_sock {
struct packet_ring_buffer tx_ring;
int copy_thresh;
#endif
struct packet_type prot_hook;
spinlock_t bind_lock;
struct mutex pg_vec_lock;
unsigned int running:1, /* prot_hook is attached*/
@ -204,6 +203,7 @@ struct packet_sock {
unsigned int tp_reserve;
unsigned int tp_loss:1;
#endif
struct packet_type prot_hook ____cacheline_aligned_in_smp;
};
struct packet_skb_cb {