core: add stat to track unresolved discards in neighbor cache
in __neigh_event_send, if we have a neighbour entry which is in
NUD_INCOMPLETE state, we enqueue any outbound frames to that neighbour
to the neighbours arp_queue, which is default capped to a length of 3
skbs. If that queue exceeds its set length, it will drop an skb on
the queue to enqueue the newly arrived skb. This results in a drop
for which we have no statistics incremented. This patch adds an
unresolved_discards stat to /proc/net/stat/ndisc_cache to track these
lost frames.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index dc420fe..aa4b708 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -75,7 +75,7 @@
unsigned long destroys; /* number of destroyed neighs */
unsigned long hash_grows; /* number of hash resizes */
- unsigned long res_failed; /* nomber of failed resolutions */
+ unsigned long res_failed; /* number of failed resolutions */
unsigned long lookups; /* number of lookups */
unsigned long hits; /* number of hits (among lookups) */
@@ -85,6 +85,8 @@
unsigned long periodic_gc_runs; /* number of periodic GC runs */
unsigned long forced_gc_runs; /* number of forced GC runs */
+
+ unsigned long unres_discards; /* number of unresolved drops */
};
#define NEIGH_CACHE_STAT_INC(tbl, field) \
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 65f01f7..f62c8af 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -930,6 +930,7 @@
buff = neigh->arp_queue.next;
__skb_unlink(buff, &neigh->arp_queue);
kfree_skb(buff);
+ NEIGH_CACHE_STAT_INC(neigh->tbl, unres_discards);
}
__skb_queue_tail(&neigh->arp_queue, skb);
}
@@ -2462,12 +2463,12 @@
struct neigh_statistics *st = v;
if (v == SEQ_START_TOKEN) {
- seq_printf(seq, "entries allocs destroys hash_grows lookups hits res_failed rcv_probes_mcast rcv_probes_ucast periodic_gc_runs forced_gc_runs\n");
+ seq_printf(seq, "entries allocs destroys hash_grows lookups hits res_failed rcv_probes_mcast rcv_probes_ucast periodic_gc_runs forced_gc_runs unresolved_discards\n");
return 0;
}
seq_printf(seq, "%08x %08lx %08lx %08lx %08lx %08lx %08lx "
- "%08lx %08lx %08lx %08lx\n",
+ "%08lx %08lx %08lx %08lx %08lx\n",
atomic_read(&tbl->entries),
st->allocs,
@@ -2483,7 +2484,8 @@
st->rcv_probes_ucast,
st->periodic_gc_runs,
- st->forced_gc_runs
+ st->forced_gc_runs,
+ st->unres_discards
);
return 0;