Date: Thu, 29 Dec 2011 20:41:16 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r228969 - head/sys/netinet Message-ID: <201112292041.pBTKfGkj071711@svn.freebsd.org>
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Author: jhb Date: Thu Dec 29 20:41:16 2011 New Revision: 228969 URL: http://svn.freebsd.org/changeset/base/228969 Log: Defer the work of freeing IPv4 multicast options from a socket to an asychronous task. This avoids tearing down multicast state including sending IGMP leave messages and reprogramming MAC filters while holding the per-protocol global pcbinfo lock that is used in the receive path of packet processing. Reviewed by: rwatson MFC after: 1 month Modified: head/sys/netinet/in_mcast.c head/sys/netinet/ip_var.h Modified: head/sys/netinet/in_mcast.c ============================================================================== --- head/sys/netinet/in_mcast.c Thu Dec 29 19:01:29 2011 (r228968) +++ head/sys/netinet/in_mcast.c Thu Dec 29 20:41:16 2011 (r228969) @@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$"); #include <sys/protosw.h> #include <sys/sysctl.h> #include <sys/ktr.h> +#include <sys/taskqueue.h> #include <sys/tree.h> #include <net/if.h> @@ -144,6 +145,8 @@ static void inm_purge(struct in_multi *) static void inm_reap(struct in_multi *); static struct ip_moptions * inp_findmoptions(struct inpcb *); +static void inp_freemoptions_internal(struct ip_moptions *); +static void inp_gcmoptions(void *, int); static int inp_get_source_filters(struct inpcb *, struct sockopt *); static int inp_join_group(struct inpcb *, struct sockopt *); static int inp_leave_group(struct inpcb *, struct sockopt *); @@ -179,6 +182,10 @@ static SYSCTL_NODE(_net_inet_ip_mcast, O CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_ip_mcast_filters, "Per-interface stack-wide source filters"); +static STAILQ_HEAD(, ip_moptions) imo_gc_list = + STAILQ_HEAD_INITIALIZER(imo_gc_list); +static struct task imo_gc_task = TASK_INITIALIZER(0, inp_gcmoptions, NULL); + /* * Inline function which wraps assertions for a valid ifp. * The ifnet layer will set the ifma's ifp pointer to NULL if the ifp @@ -1518,17 +1525,29 @@ inp_findmoptions(struct inpcb *inp) } /* - * Discard the IP multicast options (and source filters). + * Discard the IP multicast options (and source filters). To minimize + * the amount of work done while holding locks such as the INP's + * pcbinfo lock (which is used in the receive path), the free + * operation is performed asynchronously in a separate task. * * SMPng: NOTE: assumes INP write lock is held. */ void inp_freemoptions(struct ip_moptions *imo) { - struct in_mfilter *imf; - size_t idx, nmships; KASSERT(imo != NULL, ("%s: ip_moptions is NULL", __func__)); + IN_MULTI_LOCK(); + STAILQ_INSERT_TAIL(&imo_gc_list, imo, imo_link); + IN_MULTI_UNLOCK(); + taskqueue_enqueue(taskqueue_thread, &imo_gc_task); +} + +static void +inp_freemoptions_internal(struct ip_moptions *imo) +{ + struct in_mfilter *imf; + size_t idx, nmships; nmships = imo->imo_num_memberships; for (idx = 0; idx < nmships; ++idx) { @@ -1546,6 +1565,22 @@ inp_freemoptions(struct ip_moptions *imo free(imo, M_IPMOPTS); } +static void +inp_gcmoptions(void *context, int pending) +{ + struct ip_moptions *imo; + + IN_MULTI_LOCK(); + while (!STAILQ_EMPTY(&imo_gc_list)) { + imo = STAILQ_FIRST(&imo_gc_list); + STAILQ_REMOVE_HEAD(&imo_gc_list, imo_link); + IN_MULTI_UNLOCK(); + inp_freemoptions_internal(imo); + IN_MULTI_LOCK(); + } + IN_MULTI_UNLOCK(); +} + /* * Atomically get source filters on a socket for an IPv4 multicast group. * Called with INP lock held; returns with lock released. Modified: head/sys/netinet/ip_var.h ============================================================================== --- head/sys/netinet/ip_var.h Thu Dec 29 19:01:29 2011 (r228968) +++ head/sys/netinet/ip_var.h Thu Dec 29 20:41:16 2011 (r228969) @@ -93,6 +93,7 @@ struct ip_moptions { u_short imo_max_memberships; /* max memberships this socket */ struct in_multi **imo_membership; /* group memberships */ struct in_mfilter *imo_mfilters; /* source filters */ + STAILQ_ENTRY(ip_moptions) imo_link; }; struct ipstat {
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