diff options
| author | Rick Jones <rick.jones2@hp.com> | 2015-08-07 21:10:37 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-08-10 23:46:21 +0300 |
| commit | fb811395cd5a71b9e94a068f524a6f4a21b67bdb (patch) | |
| tree | 0ad6d565998e141581697b0e83cda9e13d0fab94 /net/core | |
| parent | a7854037da006a7472c48773e3190db55217ec9b (diff) | |
| download | linux-fb811395cd5a71b9e94a068f524a6f4a21b67bdb.tar.xz | |
net: add explicit logging and stat for neighbour table overflow
Add an explicit neighbour table overflow message (ratelimited) and
statistic to make diagnosing neighbour table overflows tractable in
the wild.
Diagnosing a neighbour table overflow can be quite difficult in the wild
because there is no explicit dmesg logged. Callers to neighbour code
seem to use net_dbg_ratelimit when the neighbour call fails which means
the "base message" is not emitted and the callback suppressed messages
from the ratelimiting can end-up juxtaposed with unrelated messages.
Further, a forced garbage collection will increment a stat on each call
whether it was successful in freeing-up a table entry or not, so that
statistic is only a hint. So, add a net_info_ratelimited message and
explicit statistic to the neighbour code.
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/neighbour.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 84195dacb8b6..2b515ba7e94f 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -274,8 +274,12 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device (entries >= tbl->gc_thresh2 && time_after(now, tbl->last_flush + 5 * HZ))) { if (!neigh_forced_gc(tbl) && - entries >= tbl->gc_thresh3) + entries >= tbl->gc_thresh3) { + net_info_ratelimited("%s: neighbor table overflow!\n", + tbl->id); + NEIGH_CACHE_STAT_INC(tbl, table_fulls); goto out_entries; + } } n = kzalloc(tbl->entry_size + dev->neigh_priv_len, GFP_ATOMIC); @@ -1849,6 +1853,7 @@ static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl, ndst.ndts_rcv_probes_ucast += st->rcv_probes_ucast; ndst.ndts_periodic_gc_runs += st->periodic_gc_runs; ndst.ndts_forced_gc_runs += st->forced_gc_runs; + ndst.ndts_table_fulls += st->table_fulls; } if (nla_put(skb, NDTA_STATS, sizeof(ndst), &ndst)) @@ -2717,12 +2722,12 @@ static int neigh_stat_seq_show(struct seq_file *seq, void *v) 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 unresolved_discards\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 table_fulls\n"); return 0; } seq_printf(seq, "%08x %08lx %08lx %08lx %08lx %08lx %08lx " - "%08lx %08lx %08lx %08lx %08lx\n", + "%08lx %08lx %08lx %08lx %08lx %08lx\n", atomic_read(&tbl->entries), st->allocs, @@ -2739,7 +2744,8 @@ static int neigh_stat_seq_show(struct seq_file *seq, void *v) st->periodic_gc_runs, st->forced_gc_runs, - st->unres_discards + st->unres_discards, + st->table_fulls ); return 0; |