diff options
| author | Martin KaFai Lau | 2015-07-24 09:57:43 -0700 |
|---|---|---|
| committer | David S. Miller | 2015-07-27 01:08:25 -0700 |
| commit | 8d6c31bf574177c8de48dd1387d96e1ec3a8b8bc (patch) | |
| tree | f1ff57e6fb696f41ab3e48c4b07fbcc539d52a33 /net | |
| parent | 990edb428c2c85c22ca770330437db7183cbe8b5 (diff) | |
ipv6: Avoid rt6_probe() taking writer lock in the fast path
The patch checks neigh->nud_state before acquiring the writer lock.
Note that rt6_probe() is only used in CONFIG_IPV6_ROUTER_PREF.
40 udpflood processes and a /64 gateway route are used.
The gateway has NUD_PERMANENT. Each of them is run for 30s.
At the end, the total number of finished sendto():
Before: 55M
After: 95M
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
CC: Julian Anastasov <ja@ssi.bg>
CC: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/route.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 0ef52623fc77..54fccf0d705d 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -560,6 +560,9 @@ static void rt6_probe(struct rt6_info *rt) rcu_read_lock_bh(); neigh = __ipv6_neigh_lookup_noref(rt->dst.dev, &rt->rt6i_gateway); if (neigh) { + if (neigh->nud_state & NUD_VALID) + goto out; + work = NULL; write_lock(&neigh->lock); if (!(neigh->nud_state & NUD_VALID) && @@ -583,6 +586,7 @@ static void rt6_probe(struct rt6_info *rt) schedule_work(&work->work); } +out: rcu_read_unlock_bh(); } #else |