Commit 90638a04 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller

tcp: don't clear lost_skb_hint when not necessary

Most importantly avoid doing it with cumulative ACK. However,
since we have lost_cnt_hint in the picture as well needing
adjustments, it's not as trivial as dealing with
retransmit_skb_hint (and cannot be done in the all place we
could trivially leave retransmit_skb_hint untouched).

With the previous patch, this should mostly remove O(n^2)
behavior while cumulative ACKs start flowing once rexmit
after a lossy round-trip made it through.
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ef9da47c
...@@ -2844,6 +2844,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) ...@@ -2844,6 +2844,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets)
int flag = 0; int flag = 0;
u32 pkts_acked = 0; u32 pkts_acked = 0;
u32 reord = tp->packets_out; u32 reord = tp->packets_out;
u32 prior_sacked = tp->sacked_out;
s32 seq_rtt = -1; s32 seq_rtt = -1;
s32 ca_seq_rtt = -1; s32 ca_seq_rtt = -1;
ktime_t last_ackt = net_invalid_timestamp(); ktime_t last_ackt = net_invalid_timestamp();
...@@ -2925,9 +2926,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) ...@@ -2925,9 +2926,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets)
tcp_unlink_write_queue(skb, sk); tcp_unlink_write_queue(skb, sk);
sk_wmem_free_skb(sk, skb); sk_wmem_free_skb(sk, skb);
tcp_clear_retrans_hints_partial(tp); tp->scoreboard_skb_hint = NULL;
if (skb == tp->retransmit_skb_hint) if (skb == tp->retransmit_skb_hint)
tp->retransmit_skb_hint = NULL; tp->retransmit_skb_hint = NULL;
if (skb == tp->lost_skb_hint)
tp->lost_skb_hint = NULL;
} }
if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
...@@ -2946,6 +2949,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) ...@@ -2946,6 +2949,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets)
/* Non-retransmitted hole got filled? That's reordering */ /* Non-retransmitted hole got filled? That's reordering */
if (reord < prior_fackets) if (reord < prior_fackets)
tcp_update_reordering(sk, tp->fackets_out - reord, 0); tcp_update_reordering(sk, tp->fackets_out - reord, 0);
/* No need to care for underflows here because
* the lost_skb_hint gets NULLed if we're past it
* (or something non-trivial happened)
*/
if (tcp_is_fack(tp))
tp->lost_cnt_hint -= pkts_acked;
else
tp->lost_cnt_hint -= prior_sacked - tp->sacked_out;
} }
tp->fackets_out -= min(pkts_acked, tp->fackets_out); tp->fackets_out -= min(pkts_acked, tp->fackets_out);
......
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