svn commit: r261883 - in head: sys/net usr.bin/netstat
Gleb Smirnoff
glebius at FreeBSD.org
Fri Feb 14 10:56:27 UTC 2014
Author: glebius
Date: Fri Feb 14 10:56:26 2014
New Revision: 261883
URL: http://svnweb.freebsd.org/changeset/base/261883
Log:
Whenever flowtable lookup fails, we do route lookup and then try to
insert flow entry. During the route lookup the critical section is
exited. It may happen, that after route lookup we will be executed
on an other CPU that already has such flowentry. Before this change
we simply freed the flowentry and returned to ip_output() with
failure.
Actually there is nothing wrong with using previously allocated
flow entry, updating it properly. Thus, make flowentry_insert()
return the new either old fle, and make use of it.
Count reuses as "collisions" and real inserts as "inserts".
Reviewed by: adrian
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
Modified:
head/sys/net/flowtable.c
head/sys/net/flowtable.h
head/usr.bin/netstat/flowtable.c
Modified: head/sys/net/flowtable.c
==============================================================================
--- head/sys/net/flowtable.c Fri Feb 14 10:05:21 2014 (r261882)
+++ head/sys/net/flowtable.c Fri Feb 14 10:56:26 2014 (r261883)
@@ -716,21 +716,39 @@ flow_full(struct flowtable *ft)
}
static int
+flow_matches(struct flentry *fle, uint32_t hash, uint32_t *key, uint8_t
+ proto, uint32_t fibnum)
+{
+
+ if (fle->f_fhash == hash &&
+ bcmp(&fle->f_flow, key, KEYLEN(fle->f_flags)) == 0 &&
+ proto == fle->f_proto && fibnum == fle->f_fibnum &&
+ (fle->f_rt->rt_flags & RTF_UP) &&
+ fle->f_rt->rt_ifp != NULL &&
+ (fle->f_lle->la_flags & LLE_VALID))
+ return (1);
+
+ return (0);
+}
+
+static struct flentry *
flowtable_insert(struct flowtable *ft, uint32_t hash, uint32_t *key,
uint32_t fibnum, struct route *ro, uint16_t flags)
{
struct flist *flist;
struct flentry *fle, *iter;
- int depth;
bitstr_t *mask;
+ int depth;
+ uint8_t proto;
fle = uma_zalloc(flow_zone, M_NOWAIT | M_ZERO);
if (fle == NULL)
- return (ENOMEM);
+ return (NULL);
+ proto = flags_to_proto(flags);
bcopy(key, &fle->f_flow, KEYLEN(flags));
fle->f_flags |= (flags & FL_IPV6);
- fle->f_proto = flags_to_proto(flags);
+ fle->f_proto = proto;
fle->f_rt = ro->ro_rt;
fle->f_lle = ro->ro_lle;
fle->f_fhash = hash;
@@ -748,21 +766,24 @@ flowtable_insert(struct flowtable *ft, u
}
depth = 0;
- FLOWSTAT_INC(ft, ft_collisions);
/*
* find end of list and make sure that we were not
* preempted by another thread handling this flow
*/
SLIST_FOREACH(iter, flist, f_next) {
- if (iter->f_fhash == hash && !flow_stale(ft, iter)) {
+ if (flow_matches(iter, hash, key, proto, fibnum)) {
/*
- * there was either a hash collision
- * or we lost a race to insert
+ * We probably migrated to an other CPU after
+ * lookup in flowtable_lookup_common() failed.
+ * It appeared that this CPU already has flow
+ * entry.
*/
+ iter->f_uptime = time_uptime;
+ iter->f_flags |= flags;
critical_exit();
+ FLOWSTAT_INC(ft, ft_collisions);
uma_zfree(flow_zone, fle);
-
- return (EEXIST);
+ return (iter);
}
depth++;
}
@@ -773,8 +794,9 @@ flowtable_insert(struct flowtable *ft, u
SLIST_INSERT_HEAD(flist, fle, f_next);
skip:
critical_exit();
+ FLOWSTAT_INC(ft, ft_inserts);
- return (0);
+ return (fle);
}
struct flentry *
@@ -885,12 +907,7 @@ flowtable_lookup_common(struct flowtable
critical_enter();
flist = flowtable_list(ft, hash);
SLIST_FOREACH(fle, flist, f_next)
- if (fle->f_fhash == hash && bcmp(&fle->f_flow, key,
- KEYLEN(fle->f_flags)) == 0 &&
- proto == fle->f_proto && fibnum == fle->f_fibnum &&
- (fle->f_rt->rt_flags & RTF_UP) &&
- fle->f_rt->rt_ifp != NULL &&
- (fle->f_lle->la_flags & LLE_VALID)) {
+ if (flow_matches(fle, hash, key, proto, fibnum)) {
fle->f_uptime = time_uptime;
fle->f_flags |= flags;
critical_exit();
@@ -977,17 +994,19 @@ flowtable_lookup_common(struct flowtable
ro->ro_lle = lle;
- if (flowtable_insert(ft, hash, key, fibnum, ro, flags) != 0) {
+ fle = flowtable_insert(ft, hash, key, fibnum, ro, flags);
+ if (fle == NULL) {
RTFREE(rt);
LLE_FREE(lle);
return (NULL);
}
success:
- if (fle != NULL && (m->m_flags & M_FLOWID) == 0) {
+ if (m->m_flags & M_FLOWID) {
m->m_flags |= M_FLOWID;
m->m_pkthdr.flowid = fle->f_fhash;
}
+
return (fle);
}
Modified: head/sys/net/flowtable.h
==============================================================================
--- head/sys/net/flowtable.h Fri Feb 14 10:05:21 2014 (r261882)
+++ head/sys/net/flowtable.h Fri Feb 14 10:56:26 2014 (r261883)
@@ -40,6 +40,7 @@ struct flowtable_stat {
uint64_t ft_hits;
uint64_t ft_lookups;
uint64_t ft_fail_lle_invalid;
+ uint64_t ft_inserts;
};
#ifdef _KERNEL
Modified: head/usr.bin/netstat/flowtable.c
==============================================================================
--- head/usr.bin/netstat/flowtable.c Fri Feb 14 10:05:21 2014 (r261882)
+++ head/usr.bin/netstat/flowtable.c Fri Feb 14 10:56:26 2014 (r261883)
@@ -52,10 +52,12 @@ print_stats(struct flowtable_stat *stat)
p(ft_lookups, "\t%ju lookup%s\n");
p(ft_hits, "\t%ju hit%s\n");
p2(ft_misses, "\t%ju miss%s\n");
+ p(ft_inserts, "\t%ju insert%s\n");
p(ft_collisions, "\t%ju collision%s\n");
p(ft_free_checks, "\t%ju free check%s\n");
p(ft_frees, "\t%ju free%s\n");
- p(ft_fail_lle_invalid, "\t%ju lookups w/ no resolved Layer 2 address%s\n");
+ p(ft_fail_lle_invalid,
+ "\t%ju lookup%s with not resolved Layer 2 address\n");
#undef p2
#undef p
More information about the svn-src-all
mailing list