From: Patrick McHardy <kaber@xxxxxxxxx> Date: Fri, 11 Apr 2008 15:02:06 +0200 > Al Viro wrote: > > On Fri, Apr 11, 2008 at 02:46:35PM +0200, Patrick McHardy wrote: > >> Brian Oostenbrink wrote: > >>> In vlan_skb_recv, packets are generally stripped of their vlan header, > >>> and then re-queued via netif_rx(). Is there a reason for re-queuing > >>> these instead of calling netif_receive_skb() directly? On our system > >>> (an embedded linux router), this re-queuing has a significant > >>> performance penalty. > >> Its done to save stack space. There's currently a discussion > >> about making loopback use netif_receive_skb in case enough > >> stack is still available. Once that patch gets merged I'll > >> change VLAN in a similar way. > > > > Another possibility would be to allow ->func() of packet_type to return an > > skb for reprocessing... > > That should work fine for VLAN, but not for loopback since its > called on the TX path. I think I prefer Eric's suggested way > because it doesn't require to change all the other existing > packet_type users. I think Al's idea is the most elegant proposed so far and we could do something similar on the TX side as well. Yes, it means diddling with a lot of call sites, but we do that all the time and it's heaps better then these "check the stack space remaining" hacks being proposed. -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
