989e04c5bc
Upon timeout, undo (via both timestamps/Eifel and DSACKs) was disabled if any retransmits were still in flight. The concern was perhaps that spurious retransmission sent in a previous recovery episode may trigger DSACKs to falsely undo the current recovery. However, this inadvertently misses undo opportunities (using either TCP timestamps or DSACKs) when timeout occurs during a loss episode, i.e. recurring timeouts or timeout during fast recovery. In these cases some retransmissions will be in flight but we should allow undo. Furthermore, we should only reset undo_marker and undo_retrans upon timeout if we are starting a new recovery episode. Finally, when we do reset our undo state, we now do so in a manner similar to tcp_enter_recovery(), so that we require a DSACK for each of the outstsanding retransmissions. This will achieve the original goal by requiring that we receive the same number of DSACKs as retransmissions. This patch increases the undo events by 50% on Google servers. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| soc/tegra | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||