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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