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authorEric Dumazet <edumazet@google.com>2012-08-03 21:27:25 +0000
committerDavid S. Miller <davem@davemloft.net>2012-08-04 01:27:57 -0700
commit9eb43e765368f835d92c93844ebce30da7efeb84 (patch)
treec8ae2176f95886fafd8e70e7c32f2aa6257ca73d /net/ipv4/route.c
parent40384999d142552b81aeb596c2ae663dd3ff60ce (diff)
downloadlinux-9eb43e765368f835d92c93844ebce30da7efeb84.tar.gz
ipv4: Introduce IN_DEV_NET_ROUTE_LOCALNET
performance profiles show a high cost in the IN_DEV_ROUTE_LOCALNET()
call done in ip_route_input_slow(), because of multiple dereferences,
even if cache lines are clean and available in cpu caches.

Since we already have the 'net' pointer, introduce
IN_DEV_NET_ROUTE_LOCALNET() macro avoiding two dereferences
(dev_net(in_dev->dev))

Also change the tests to use IN_DEV_NET_ROUTE_LOCALNET() only if saddr
or/and daddr are loopback addresse.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/route.c')
-rw-r--r--net/ipv4/route.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index e4ba974f143c..21ad369014c0 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1587,11 +1587,14 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	if (ipv4_is_zeronet(daddr))
 		goto martian_destination;
 
-	if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
-		if (ipv4_is_loopback(daddr))
+	/* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
+	 * and call it once if daddr or/and saddr are loopback addresses
+	 */
+	if (ipv4_is_loopback(daddr)) {
+		if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
 			goto martian_destination;
-
-		if (ipv4_is_loopback(saddr))
+	} else if (ipv4_is_loopback(saddr)) {
+		if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
 			goto martian_source;
 	}