Author: tuexen
Date: Fri May 17 08:21:27 2019
New Revision: 347901
URL: https://svnweb.freebsd.org/changeset/base/347901
Log:
MFC r347381:
Prevent cwnd to collapse down to 1 MSS after exiting recovery.
This is descrined in RFC 6582, which updates RFC 3782.
Modified:
stable/12/sys/netinet/cc/cc_cubic.c
stable/12/sys/netinet/cc/cc_htcp.c
stable/12/sys/netinet/cc/cc_newreno.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/netinet/cc/cc_cubic.c
==============================================================================
--- stable/12/sys/netinet/cc/cc_cubic.c Fri May 17 08:19:43 2019
(r347900)
+++ stable/12/sys/netinet/cc/cc_cubic.c Fri May 17 08:21:27 2019
(r347901)
@@ -324,7 +324,12 @@ cubic_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
- CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+ /*
+ * Ensure that cwnd does not collapse to 1 MSS under
+ * adverse conditions. Implements RFC6582
+ */
+ CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
+ CCV(ccv, t_maxseg);
else
/* Update cwnd based on beta and adjusted max_cwnd. */
CCV(ccv, snd_cwnd) = max(1, ((CUBIC_BETA *
Modified: stable/12/sys/netinet/cc/cc_htcp.c
==============================================================================
--- stable/12/sys/netinet/cc/cc_htcp.c Fri May 17 08:19:43 2019
(r347900)
+++ stable/12/sys/netinet/cc/cc_htcp.c Fri May 17 08:21:27 2019
(r347901)
@@ -366,7 +366,12 @@ htcp_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
- CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+ /*
+ * Ensure that cwnd down not collape to 1 MSS under
+ * adverse conditions. Implements RFC6582
+ */
+ CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
+ CCV(ccv, t_maxseg);
else
CCV(ccv, snd_cwnd) = max(1, ((htcp_data->beta *
htcp_data->prev_cwnd / CCV(ccv, t_maxseg))
Modified: stable/12/sys/netinet/cc/cc_newreno.c
==============================================================================
--- stable/12/sys/netinet/cc/cc_newreno.c Fri May 17 08:19:43 2019
(r347900)
+++ stable/12/sys/netinet/cc/cc_newreno.c Fri May 17 08:21:27 2019
(r347901)
@@ -299,7 +299,12 @@ newreno_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
- CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+ /*
+ * Ensure that cwnd does not collapse to 1 MSS under
+ * adverse conditons. Implements RFC6582
+ */
+ CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
+ CCV(ccv, t_maxseg);
else
CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
}
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