The patch checks neigh->nud_state before acquiring the writer lock.
Note that rt6_probe() is only used in CONFIG_IPV6_ROUTER_PREF.
I also take this chance to re-arrange the code.
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 After
55M 95M
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
Cc: Hannes Frederic Sowa <han...@stressinduktion.org>
---
net/ipv6/route.c | 41 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 21 deletions(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 6090969..a6c6b5a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -544,6 +544,7 @@ static void rt6_probe_deferred(struct work_struct *w)
static void rt6_probe(struct rt6_info *rt)
{
+ struct __rt6_probe_work *work;
struct neighbour *neigh;
/*
* Okay, this does not seem to be appropriate
@@ -558,34 +559,32 @@ 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) {
- write_lock(&neigh->lock);
if (neigh->nud_state & NUD_VALID)
goto out;
- }
-
- if (!neigh ||
- time_after(jiffies, neigh->updated +
rt->rt6i_idev->cnf.rtr_probe_interval)) {
- struct __rt6_probe_work *work;
+ work = NULL;
+ write_lock(&neigh->lock);
+ if (!(neigh->nud_state & NUD_VALID) &&
+ time_after(jiffies, neigh->updated +
rt->rt6i_idev->cnf.rtr_probe_interval)) {
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ if (work) {
+ __neigh_set_probe_once(neigh);
+ }
+ }
+ write_unlock(&neigh->lock);
+ } else {
work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ }
- if (neigh && work)
- __neigh_set_probe_once(neigh);
-
- if (neigh)
- write_unlock(&neigh->lock);
+ if (work) {
+ INIT_WORK(&work->work, rt6_probe_deferred);
+ work->target = rt->rt6i_gateway;
+ dev_hold(rt->dst.dev);
+ work->dev = rt->dst.dev;
+ schedule_work(&work->work);
+ }
- if (work) {
- INIT_WORK(&work->work, rt6_probe_deferred);
- work->target = rt->rt6i_gateway;
- dev_hold(rt->dst.dev);
- work->dev = rt->dst.dev;
- schedule_work(&work->work);
- }
- } else {
out:
- write_unlock(&neigh->lock);
- }
rcu_read_unlock_bh();
}
#else
--
1.8.1
--
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