Messages in this thread | | | Subject | Re: ixgbe truesize underestimation fix missing? | From | Eric Dumazet <> | Date | Mon, 13 Feb 2012 11:46:00 +0100 |
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Le lundi 13 février 2012 à 10:57 +0100, Christian Brunner a écrit : > 2012/2/13 Eric Dumazet <eric.dumazet@gmail.com>: > > Le lundi 13 février 2012 à 09:45 +0100, Christian Brunner a écrit : > >> Back in Oktober, there was a patch by Eric Dumazet for the ixgbe > >> driver to fix the skb truesize underestimation (commit > >> 98130646770db42cd14c44ba0d7f2d0eb8078820). It changed only one line in > >> ixgbe_main.c: > >> > >> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> @@ -1326,7 +1326,7 @@ static bool ixgbe_clean_rx_irq(struct > >> ixgbe_q_vector *q_vector, > >> skb->len += upper_len; > >> skb->data_len += upper_len; > >> - skb->truesize += upper_len; > >> + skb->truesize += PAGE_SIZE / 2; > >> } i++; > >> > >> > >> But when I look at the current code (3.2.5 or 3.3rc), skb->truesize is > >> still increased by the same value as skb->data_len. > >> > >> 1228 skb->data_len += frag_list_size; > >> 1229 skb->truesize += frag_list_size; > >> > >> Is it posible that there was a merge conflict, or am I missing something here? > > > > Maybe a problem in your local tree ? > > > > I can see proper fix in current tree. > > Ahh... Sorry. I Was looking at the wrong place - > ixgbe_transform_rsc_queue() has code that is quite similar. > > This however makes me wonder, why we are using "skb->len" for > increasing the frag_list_size, as skb->len might be smaller than > skb->truesize. > > Shouldn't we add a frag_list_truesize counter in ixgbe_transform_rsc_queue() ?
Probably, but you should raise this discussion on netdev, not lkml, and based on net-next tree, as ixgbe_transform_rsc_queue() doesnt exist anymore ;)
Note that in this case (RSC) truesize underestimation is small since typical segment size is very close to PAGE_SIZE/2
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