On Fri, 22 Jan 2021 11:53:46 +0100 Eric Dumazet wrote: > On Fri, Jan 22, 2021 at 11:28 AM Pengcheng Yang <yan...@wangsu.com> wrote: > > > > When CA_STATE is in DISORDER, the TLP timer is not set when receiving > > an ACK (a cumulative ACK covered out-of-order data) causes CA_STATE to > > change from DISORDER to OPEN. If the sender is app-limited, it can only > > wait for the RTO timer to expire and retransmit. > > > > The reason for this is that the TLP timer is set before CA_STATE changes > > in tcp_ack(), so we delay the time point of calling tcp_set_xmit_timer() > > until after tcp_fastretrans_alert() returns and remove the > > FLAG_SET_XMIT_TIMER from ack_flag when the RACK reorder timer is set. > > > > This commit has two additional benefits: > > 1) Make sure to reset RTO according to RFC6298 when receiving ACK, to > > avoid spurious RTO caused by RTO timer early expires. > > 2) Reduce the xmit timer reschedule once per ACK when the RACK reorder > > timer is set. > > > > Link: > > https://lore.kernel.org/netdev/1611139794-11254-1-git-send-email-yan...@wangsu.com > > Signed-off-by: Pengcheng Yang <yan...@wangsu.com> > > Cc: Neal Cardwell <ncardw...@google.com> > > This looks like a very nice patch, let me run packetdrill tests on it. > > By any chance, have you cooked a packetdrill test showing the issue > (failing on unpatched kernel) ?
Any guidance on backporting / fixes tag? (once the packetdrill questions are satisfied)
