From owner-svn-src-all@FreeBSD.ORG Sat Oct 16 05:37:45 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9B2881065670; Sat, 16 Oct 2010 05:37:45 +0000 (UTC) (envelope-from lstewart@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 892CC8FC0A; Sat, 16 Oct 2010 05:37:45 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o9G5bj1S025747; Sat, 16 Oct 2010 05:37:45 GMT (envelope-from lstewart@svn.freebsd.org) Received: (from lstewart@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o9G5bjFj025745; Sat, 16 Oct 2010 05:37:45 GMT (envelope-from lstewart@svn.freebsd.org) Message-Id: <201010160537.o9G5bjFj025745@svn.freebsd.org> From: Lawrence Stewart Date: Sat, 16 Oct 2010 05:37:45 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r213912 - head/sys/netinet X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 16 Oct 2010 05:37:45 -0000 Author: lstewart Date: Sat Oct 16 05:37:45 2010 New Revision: 213912 URL: http://svn.freebsd.org/changeset/base/213912 Log: - Switch the "net.inet.tcp.reass.cursegments" and "net.inet.tcp.reass.maxsegments" sysctl variables to be based on UMA zone stats. The value returned by the cursegments sysctl is approximate owing to the way in which uma_zone_get_cur is implemented. - Discontinue use of V_tcp_reass_qsize as a global reassembly segment count variable in the reassembly implementation. The variable was used without proper synchronisation and was duplicating accounting done by UMA already. The lack of synchronisation was particularly problematic on SMP systems terminating many TCP sessions, resulting in poor TCP performance for connections with non-zero packet loss. Sponsored by: FreeBSD Foundation Reviewed by: andre, gnn, rpaulo (as part of a larger patch) MFC after: 2 weeks Modified: head/sys/netinet/tcp_reass.c Modified: head/sys/netinet/tcp_reass.c ============================================================================== --- head/sys/netinet/tcp_reass.c Sat Oct 16 04:41:45 2010 (r213911) +++ head/sys/netinet/tcp_reass.c Sat Oct 16 05:37:45 2010 (r213912) @@ -74,19 +74,22 @@ __FBSDID("$FreeBSD$"); #include #endif /* TCPDEBUG */ +static int tcp_reass_sysctl_maxseg(SYSCTL_HANDLER_ARGS); +static int tcp_reass_sysctl_qsize(SYSCTL_HANDLER_ARGS); + SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0, "TCP Segment Reassembly Queue"); static VNET_DEFINE(int, tcp_reass_maxseg) = 0; #define V_tcp_reass_maxseg VNET(tcp_reass_maxseg) -SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RDTUN, - &VNET_NAME(tcp_reass_maxseg), 0, +SYSCTL_VNET_PROC(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RDTUN, + &VNET_NAME(tcp_reass_maxseg), 0, &tcp_reass_sysctl_maxseg, "I", "Global maximum number of TCP Segments in Reassembly Queue"); static VNET_DEFINE(int, tcp_reass_qsize) = 0; #define V_tcp_reass_qsize VNET(tcp_reass_qsize) -SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD, - &VNET_NAME(tcp_reass_qsize), 0, +SYSCTL_VNET_PROC(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD, + &VNET_NAME(tcp_reass_qsize), 0, &tcp_reass_sysctl_qsize, "I", "Global number of TCP Segments currently in Reassembly Queue"); static VNET_DEFINE(int, tcp_reass_maxqlen) = 48; @@ -148,7 +151,6 @@ tcp_reass_flush(struct tcpcb *tp) m_freem(qe->tqe_m); uma_zfree(V_tcp_reass_zone, qe); tp->t_segqlen--; - V_tcp_reass_qsize--; } KASSERT((tp->t_segqlen == 0), @@ -156,6 +158,20 @@ tcp_reass_flush(struct tcpcb *tp) tp, tp->t_segqlen)); } +static int +tcp_reass_sysctl_maxseg(SYSCTL_HANDLER_ARGS) +{ + V_tcp_reass_maxseg = uma_zone_get_max(V_tcp_reass_zone); + return (sysctl_handle_int(oidp, arg1, arg2, req)); +} + +static int +tcp_reass_sysctl_qsize(SYSCTL_HANDLER_ARGS) +{ + V_tcp_reass_qsize = uma_zone_get_cur(V_tcp_reass_zone); + return (sysctl_handle_int(oidp, arg1, arg2, req)); +} + int tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m) { @@ -184,12 +200,10 @@ tcp_reass(struct tcpcb *tp, struct tcphd * Limit the number of segments in the reassembly queue to prevent * holding on to too many segments (and thus running out of mbufs). * Make sure to let the missing segment through which caused this - * queue. Always keep one global queue entry spare to be able to - * process the missing segment. + * queue. */ if (th->th_seq != tp->rcv_nxt && - (V_tcp_reass_qsize + 1 >= V_tcp_reass_maxseg || - tp->t_segqlen >= V_tcp_reass_maxqlen)) { + tp->t_segqlen >= V_tcp_reass_maxqlen) { V_tcp_reass_overflows++; TCPSTAT_INC(tcps_rcvmemdrop); m_freem(m); @@ -209,7 +223,6 @@ tcp_reass(struct tcpcb *tp, struct tcphd return (0); } tp->t_segqlen++; - V_tcp_reass_qsize++; /* * Find a segment which begins after this one does. @@ -236,7 +249,6 @@ tcp_reass(struct tcpcb *tp, struct tcphd m_freem(m); uma_zfree(V_tcp_reass_zone, te); tp->t_segqlen--; - V_tcp_reass_qsize--; /* * Try to present any queued data * at the left window edge to the user. @@ -273,7 +285,6 @@ tcp_reass(struct tcpcb *tp, struct tcphd m_freem(q->tqe_m); uma_zfree(V_tcp_reass_zone, q); tp->t_segqlen--; - V_tcp_reass_qsize--; q = nq; } @@ -310,7 +321,6 @@ present: sbappendstream_locked(&so->so_rcv, q->tqe_m); uma_zfree(V_tcp_reass_zone, q); tp->t_segqlen--; - V_tcp_reass_qsize--; q = nq; } while (q && q->tqe_th->th_seq == tp->rcv_nxt); ND6_HINT(tp);