On Wed, 2013-02-20 at 07:11 -0800, Eric Dumazet wrote: > On Wed, 2013-02-20 at 10:15 +0100, Johannes Berg wrote: > > > OTOH, this affects the protocol, and when you really can't allocate any > > order-1 pages you pointed out yourself that many other things also won't > > work, so I'm not really sure it makes a big difference if we change the > > driver? > > It will make a huge difference, even on non pressure mode, as TCP > receive window will grow twice faster. Hmm, why does that depend on the allocation size? > Unless wifi speed reaches 10Gbps, following patch should do the trick > > > diff --git a/drivers/net/wireless/iwlwifi/dvm/rx.c b/drivers/net/wireless/iwlwifi/dvm/rx.c > index a4eed20..77a3ee3 100644 > --- a/drivers/net/wireless/iwlwifi/dvm/rx.c > +++ b/drivers/net/wireless/iwlwifi/dvm/rx.c > @@ -750,7 +750,12 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv, > /* Dont use dev_alloc_skb(), we'll have enough headroom once > * ieee80211_hdr pulled. > */ > - skb = alloc_skb(128, GFP_ATOMIC); > + fraglen = 128; > + /* if we use order-1 pages, copy to get better TCP performance */ > + if (rxb->truesize > PAGE_SIZE) > + fraglen = max_t(unsigned, fraglen, len); > + > + skb = alloc_skb(fraglen, GFP_ATOMIC); Hmm, I don't quite understand -- that's not doing any copy? FWIW if you do the copy you should not "steal" the pages, then they'd be recycled in the RX ring right away. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
