From 30038fc61adfdab162b1966e34261f06eda67f02 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 28 Aug 2009 23:52:01 -0700 Subject: [PATCH] net: ip_rt_send_redirect() optimization While doing some forwarding benchmarks, I noticed ip_rt_send_redirect() is rather expensive, even if send_redirects is false for the device. Fix is to avoid two atomic ops, we dont really need to take a reference on in_dev Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/route.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index fafbe163e2b..91867d3e632 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1514,13 +1514,17 @@ static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) void ip_rt_send_redirect(struct sk_buff *skb) { struct rtable *rt = skb_rtable(skb); - struct in_device *in_dev = in_dev_get(rt->u.dst.dev); + struct in_device *in_dev; + int log_martians; - if (!in_dev) + rcu_read_lock(); + in_dev = __in_dev_get_rcu(rt->u.dst.dev); + if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { + rcu_read_unlock(); return; - - if (!IN_DEV_TX_REDIRECTS(in_dev)) - goto out; + } + log_martians = IN_DEV_LOG_MARTIANS(in_dev); + rcu_read_unlock(); /* No redirected packets during ip_rt_redirect_silence; * reset the algorithm. @@ -1533,7 +1537,7 @@ void ip_rt_send_redirect(struct sk_buff *skb) */ if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) { rt->u.dst.rate_last = jiffies; - goto out; + return; } /* Check for load limit; set rate_last to the latest sent @@ -1547,7 +1551,7 @@ void ip_rt_send_redirect(struct sk_buff *skb) rt->u.dst.rate_last = jiffies; ++rt->u.dst.rate_tokens; #ifdef CONFIG_IP_ROUTE_VERBOSE - if (IN_DEV_LOG_MARTIANS(in_dev) && + if (log_martians && rt->u.dst.rate_tokens == ip_rt_redirect_number && net_ratelimit()) printk(KERN_WARNING "host %pI4/if%d ignores redirects for %pI4 to %pI4.\n", @@ -1555,8 +1559,6 @@ void ip_rt_send_redirect(struct sk_buff *skb) &rt->rt_dst, &rt->rt_gateway); #endif } -out: - in_dev_put(in_dev); } static int ip_error(struct sk_buff *skb) -- 2.20.1