[PATCH net-next 4/6] ipv4: rate limit updating of next hop exceptions with same pmtu
From: Timo Teräs <hidden>
Date: 2013-05-27 11:14:46
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
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 <redacted> --- net/ipv4/route.c | 4 ++++ 1 file changed, 4 insertions(+)
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 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 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);
--
1.8.2.3