ipv4: rate limit updating of next hop exceptions with same pmtu
The tunnel devices call update_pmtu for each packet sent, this causes
contention on the fnhe_lock. Ignore the pmtu update if pmtu is not
actually changed, and there is still plenty of time before the entry
expires.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 561a378..a4082be 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -947,6 +947,10 @@
if (mtu < ip_rt_min_pmtu)
mtu = ip_rt_min_pmtu;
+ if (rt->rt_pmtu == mtu &&
+ time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
+ return;
+
rcu_read_lock();
if (fib_lookup(dev_net(dst->dev), fl4, &res) == 0) {
struct fib_nh *nh = &FIB_RES_NH(res);