On Wed, 2015-05-27 at 09:38 +0800, Herbert Xu wrote: > On Tue, May 26, 2015 at 05:36:34PM -0700, Eric Dumazet wrote: > > > > tldr: "TSO with max_segs==1" <is the same than> "no TSO/GSO" > > Not really. They're not identical. For example, before your > patch a packet greater than MSS with TSO disabled would call > tcp_nagle_test, with your patch it will call tcp_tso_should_defer > instead.
Well, given that a device can set gso_max_segs to one, if there is a bug here we'll need to fix it asap. Fact that Nagle or tso should defer applies in this corner case is not very important here, unless you have a specific case in mind ? Anyway I double checked and I believes it is fine. We normally deal with dynamic MSS changes, even for non GSO cases. A non GSO packet temporarily becomes a GSO one in tcp_init_tso_segs() (because its skb->len is bigger than cur_mss) Then we split it. Nagle or tso should defer would take same decision : send one full MSS. By the time the last 'segment' (possibly smaller than mss) will be considered, Nagle might apply there. Thanks ! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
