On 03/03/2013 20:35, Eric Dumazet wrote:
On Wed, 2013-02-27 at 09:55 -0800, Eliezer Tamir wrote:
index 821c7f4..d1d1016 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -408,6 +408,10 @@ struct sk_buff {
struct sock *sk;
struct net_device *dev;
+#ifdef CONFIG_INET_LL_RX_POLL
+ struct napi_struct *dev_ref; /* where this skb came from */
+#endif
+
/*
* This is the control buffer. It is free to use for every
* layer. Please put your private variables there. If you
Yes, thats the killer, because :
1) It adds 8 bytes per skb, and we are going to reach the 256 bytes per
sk_buff boundary. cloned skbs will use an extra cache line.
It might make sense to union this on dma_cookie, as dma_cookie is only
used on TX path.
I will try this out.
2) We need to reference count napi structs.
For 2) , we would need to add a percpu ref counter (a bit like struct
netdevice -> pcpu_refcnt)
Alternative to 2) would be to use a generation id, incremented every
time a napi used in spin polling enabled driver is dismantled (and freed
after RCU grace period)
I like this option, because one would assume that the life expectancy of
a napi is rather long. We can just increment the generation id any time
any napi is disabled, which simplifies things.
There could be other configuration changes that would make our notion on
where to poll outdated, for example, someone may have reprogrammed an RX
filter. This is not as catastrophic as a napi going away but still.
Would it make sense to make this a generic mechanism?
One could for example increment the generation id every time the RTNL is
taken. or is this too much?
Thanks,
Eliezer
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
