Author: jtl
Date: Wed Oct 12 02:30:33 2016
New Revision: 307083
URL: https://svnweb.freebsd.org/changeset/base/307083
Log:
Currently, when tcp_input() receives a packet on a session that matches a
TCPCB, it checks (so->so_options & SO_ACCEPTCONN) to determine whether or
not the socket is a listening socket. However, this causes the code to
access a different cacheline. If we first check if the socket is in the
LISTEN state, we can avoid accessing so->so_options when processing packets
received for ESTABLISHED sessions.
If INVARIANTS is defined, the code still needs to access both variables to
check that so->so_options is consistent with the state.
Reviewed by: gallatin
MFC after: 1 week
Sponsored by: Netflix
Modified:
head/sys/netinet/tcp_input.c
Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c Wed Oct 12 02:16:42 2016
(r307082)
+++ head/sys/netinet/tcp_input.c Wed Oct 12 02:30:33 2016
(r307083)
@@ -1071,11 +1071,11 @@ relocked:
* state) we look into the SYN cache if this is a new connection
* attempt or the completion of a previous one.
*/
- if (so->so_options & SO_ACCEPTCONN) {
+ KASSERT(tp->t_state == TCPS_LISTEN || !(so->so_options & SO_ACCEPTCONN),
+ ("%s: so accepting but tp %p not listening", __func__, tp));
+ if (tp->t_state == TCPS_LISTEN && (so->so_options & SO_ACCEPTCONN)) {
struct in_conninfo inc;
- KASSERT(tp->t_state == TCPS_LISTEN, ("%s: so accepting but "
- "tp not listening", __func__));
bzero(&inc, sizeof(inc));
#ifdef INET6
if (isipv6) {
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