From e0850bdedc22ccc536039b1cb832cf383cafc6f8 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 16 Jan 2018 15:08:50 -0800 Subject: [PATCH] tc: red: allow setting th_min and th_max to the same value Setting th_min and th_max to the same value may be useful for DCTCP deployments. The original DCTCP paper describes it as a simplest way of achieving simple ECN threshold marking. Indeed, there doesn't seem to be any simpler qdisc in Linux which would allow such a setup today. Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Signed-off-by: David Ahern --- tc/tc_red.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tc/tc_red.c b/tc/tc_red.c index 1f82ef1a..178fe088 100644 --- a/tc/tc_red.c +++ b/tc/tc_red.c @@ -30,7 +30,9 @@ int tc_red_eval_P(unsigned int qmin, unsigned int qmax, double prob) { int i = qmax - qmin; - if (i <= 0) + if (!i) + return 0; + if (i < 0) return -1; prob /= i;