svn commit: r343920 - head/sys/netinet/cc
Michael Tuexen
tuexen at FreeBSD.org
Fri Feb 8 20:42:50 UTC 2019
Author: tuexen
Date: Fri Feb 8 20:42:49 2019
New Revision: 343920
URL: https://svnweb.freebsd.org/changeset/base/343920
Log:
Ensure that when using the TCP CDG congestion control and setting the
sysctl variable net.inet.tcp.cc.cdg.smoothing_factor to 0, the smoothing
is disabled. Without this patch, a division by zero orrurs.
PR: 193762
Reviewed by: lstewart@, rrs@
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D19071
Modified:
head/sys/netinet/cc/cc_cdg.c
Modified: head/sys/netinet/cc/cc_cdg.c
==============================================================================
--- head/sys/netinet/cc/cc_cdg.c Fri Feb 8 20:34:47 2019 (r343919)
+++ head/sys/netinet/cc/cc_cdg.c Fri Feb 8 20:42:49 2019 (r343920)
@@ -592,7 +592,11 @@ cdg_ack_received(struct cc_var *ccv, uint16_t ack_type
qdiff_min = ((long)(cdg_data->minrtt_in_rtt -
cdg_data->minrtt_in_prevrtt) << D_P_E );
- calc_moving_average(cdg_data, qdiff_max, qdiff_min);
+ if (cdg_data->sample_q_size == 0) {
+ cdg_data->max_qtrend = qdiff_max;
+ cdg_data->min_qtrend = qdiff_min;
+ } else
+ calc_moving_average(cdg_data, qdiff_max, qdiff_min);
/* Probabilistic backoff with respect to gradient. */
if (slowstart && qdiff_min > 0)
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