Date: Tue, 28 Jan 2014 20:30:01 GMT From: dfilter@FreeBSD.ORG (dfilter service) To: freebsd-net@FreeBSD.org Subject: Re: kern/183659: commit references a PR Message-ID: <201401282030.s0SKU15n097273@freefall.freebsd.org>
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The following reply was made to PR kern/183659; it has been noted by GNATS. From: dfilter@FreeBSD.ORG (dfilter service) To: bug-followup@FreeBSD.org Cc: Subject: Re: kern/183659: commit references a PR Date: Tue, 28 Jan 2014 20:28:45 +0000 (UTC) Author: gnn Date: Tue Jan 28 20:28:32 2014 New Revision: 261242 URL: http://svnweb.freebsd.org/changeset/base/261242 Log: Decrease lock contention within the TCP accept case by removing the INP_INFO lock from tcp_usr_accept. As the PR/patch states this was following the advice already in the code. See the PR below for a full disucssion of this change and its measured effects. PR: 183659 Submitted by: Julian Charbon Reviewed by: jhb Modified: head/sys/netinet/tcp_syncache.c head/sys/netinet/tcp_usrreq.c Modified: head/sys/netinet/tcp_syncache.c ============================================================================== --- head/sys/netinet/tcp_syncache.c Tue Jan 28 19:12:31 2014 (r261241) +++ head/sys/netinet/tcp_syncache.c Tue Jan 28 20:28:32 2014 (r261242) @@ -682,7 +682,7 @@ syncache_socket(struct syncache *sc, str * connection when the SYN arrived. If we can't create * the connection, abort it. */ - so = sonewconn(lso, SS_ISCONNECTED); + so = sonewconn(lso, 0); if (so == NULL) { /* * Drop the connection; we will either send a RST or @@ -922,6 +922,8 @@ syncache_socket(struct syncache *sc, str INP_WUNLOCK(inp); + soisconnected(so); + TCPSTAT_INC(tcps_accepts); return (so); Modified: head/sys/netinet/tcp_usrreq.c ============================================================================== --- head/sys/netinet/tcp_usrreq.c Tue Jan 28 19:12:31 2014 (r261241) +++ head/sys/netinet/tcp_usrreq.c Tue Jan 28 20:28:32 2014 (r261242) @@ -610,13 +610,6 @@ out: /* * Accept a connection. Essentially all the work is done at higher levels; * just return the address of the peer, storing through addr. - * - * The rationale for acquiring the tcbinfo lock here is somewhat complicated, - * and is described in detail in the commit log entry for r175612. Acquiring - * it delays an accept(2) racing with sonewconn(), which inserts the socket - * before the inpcb address/port fields are initialized. A better fix would - * prevent the socket from being placed in the listen queue until all fields - * are fully initialized. */ static int tcp_usr_accept(struct socket *so, struct sockaddr **nam) @@ -633,7 +626,6 @@ tcp_usr_accept(struct socket *so, struct inp = sotoinpcb(so); KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL")); - INP_INFO_RLOCK(&V_tcbinfo); INP_WLOCK(inp); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { error = ECONNABORTED; @@ -653,7 +645,6 @@ tcp_usr_accept(struct socket *so, struct out: TCPDEBUG2(PRU_ACCEPT); INP_WUNLOCK(inp); - INP_INFO_RUNLOCK(&V_tcbinfo); if (error == 0) *nam = in_sockaddr(port, &addr); return error; _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
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