tcp: invalidate rate samples during SACK reneging
Mark tcp_sock during a SACK reneging event and invalidate rate samples while marked. Such rate samples may overestimate bw by including packets that were SACKed before reneging. < ack 6001 win 10000 sack 7001:38001 < ack 7001 win 0 sack 8001:38001 // Reneg detected > seq 7001:8001 // RTO, SACK cleared. < ack 38001 win 10000 In above example the rate sample taken after the last ack will count 7001-38001 as delivered while the actual delivery rate likely could be much lower i.e. 7001-8001. This patch adds a new field tcp_sock.sack_reneg and marks it when we declare SACK reneging and entering TCP_CA_Loss, and unmarks it after the last rate sample was taken before moving back to TCP_CA_Open. This patch also invalidates rate samples taken while tcp_sock.is_sack_reneg is set. Fixes: b9f64820 ("tcp: track data delivery rate for a TCP connection") Signed-off-by:Yousuk Seung <ysseung@google.com> Signed-off-by:
Neal Cardwell <ncardwell@google.com> Signed-off-by:
Yuchung Cheng <ycheng@google.com> Acked-by:
Soheil Hassas Yeganeh <soheil@google.com> Acked-by:
Eric Dumazet <edumazet@google.com> Acked-by:
Priyaranjan Jha <priyarjha@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
195bd525
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