| Message ID | 1375792738-19099-1-git-send-email-tingw.liu@gmail.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Tingwei Liu <tingw.liu@gmail.com> Date: Tue, 6 Aug 2013 20:38:58 +0800 > When tcp keepalive working elapsed calculated twice while the first time is not needed! > > CC: Eric Dumazet <eric.dumazet@gmail.com> > CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> > Signed-off-by: Tingwei Liu <tingw.liu@gmail.com> Please put a space after "tcp:" in your Subject line prefixes, it looks awful the way you've done it here. > @@ -591,11 +591,11 @@ static void tcp_keepalive_timer (unsigned long data) > if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) > goto out; > > - elapsed = keepalive_time_when(tp); > - > /* It is alive without keepalive 8) */ > - if (tp->packets_out || tcp_send_head(sk)) > + if (tp->packets_out || tcp_send_head(sk)) { > + elapsed = keepalive_time_when(tp); > goto resched; > + } > > elapsed = keepalive_time_elapsed(tp); This is overkill, just delete the second assignment. Your version makes the code look less elegant and also makes it harder to audit. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 2013-08-09 at 11:12 -0700, David Miller wrote: > From: Tingwei Liu <tingw.liu@gmail.com> > Date: Tue, 6 Aug 2013 20:38:58 +0800 > > > When tcp keepalive working elapsed calculated twice while the first time is not needed! > > > > CC: Eric Dumazet <eric.dumazet@gmail.com> > > CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> > > Signed-off-by: Tingwei Liu <tingw.liu@gmail.com> > > > Please put a space after "tcp:" in your Subject line prefixes, it looks > awful the way you've done it here. > > > @@ -591,11 +591,11 @@ static void tcp_keepalive_timer (unsigned long data) > > if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) > > goto out; > > > > - elapsed = keepalive_time_when(tp); > > - > > /* It is alive without keepalive 8) */ > > - if (tp->packets_out || tcp_send_head(sk)) > > + if (tp->packets_out || tcp_send_head(sk)) { > > + elapsed = keepalive_time_when(tp); > > goto resched; > > + } > > > > elapsed = keepalive_time_elapsed(tp); > > This is overkill, just delete the second assignment. Your version makes > the code look less elegant and also makes it harder to audit. > -- As a matter of fact, keepalive_time_when(tp) and keepalive_time_elapsed(tp) are different ;) This is very slow path in TCP stack, so it should not matter a lot. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 4b85e6f..03091d9 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -591,11 +591,11 @@ static void tcp_keepalive_timer (unsigned long data) if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) goto out; - elapsed = keepalive_time_when(tp); - /* It is alive without keepalive 8) */ - if (tp->packets_out || tcp_send_head(sk)) + if (tp->packets_out || tcp_send_head(sk)) { + elapsed = keepalive_time_when(tp); goto resched; + } elapsed = keepalive_time_elapsed(tp);
When tcp keepalive working elapsed calculated twice while the first time is not needed! CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: Tingwei Liu <tingw.liu@gmail.com> --- net/ipv4/tcp_timer.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)