[4.2.y-ckt stable] Patch "tcp: convert cached rtt from usec to jiffies when feeding initial rto" has been added to the 4.2.y-ckt tree

Kamal Mostafa kamal at canonical.com
Tue Mar 15 23:26:43 UTC 2016


This is a note to let you know that I have just added a patch titled

    tcp: convert cached rtt from usec to jiffies when feeding initial rto

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From e040b6cb6cebaacecf49b2901ddcbdb86e9b6b1b Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov at yandex-team.ru>
Date: Sun, 21 Feb 2016 10:12:39 +0300
Subject: tcp: convert cached rtt from usec to jiffies when feeding initial rto

commit 9bdfb3b79e61c60e1a3e2dc05ad164528afa6b8a upstream.

Currently it's converted into msecs, thus HZ=1000 intact.

Signed-off-by: Konstantin Khlebnikov <khlebnikov at yandex-team.ru>
Fixes: 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution")
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv4/tcp_metrics.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index a51d63a..9c840c5 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -566,7 +566,7 @@ reset:
 	 */
 	if (crtt > tp->srtt_us) {
 		/* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
-		crtt /= 8 * USEC_PER_MSEC;
+		crtt /= 8 * USEC_PER_SEC / HZ;
 		inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
 	} else if (tp->srtt_us == 0) {
 		/* RFC6298: 5.7 We've failed to get a valid RTT sample from
--
2.7.0





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