From 9eb43e765368f835d92c93844ebce30da7efeb84 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 3 Aug 2012 21:27:25 +0000
Subject: [PATCH] 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>
---
include/linux/inetdevice.h | 11 +++++++++--
net/ipv4/route.c | 11 +++++++----
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 67f9ddacb70c..d032780d0ce5 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -104,9 +104,14 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
#define IN_DEV_ANDCONF(in_dev, attr) \
(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr) && \
IN_DEV_CONF_GET((in_dev), attr))
-#define IN_DEV_ORCONF(in_dev, attr) \
- (IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr) || \
+
+#define IN_DEV_NET_ORCONF(in_dev, net, attr) \
+ (IPV4_DEVCONF_ALL(net, attr) || \
IN_DEV_CONF_GET((in_dev), attr))
+
+#define IN_DEV_ORCONF(in_dev, attr) \
+ IN_DEV_NET_ORCONF(in_dev, dev_net(in_dev->dev), attr)
+
#define IN_DEV_MAXCONF(in_dev, attr) \
(max(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr), \
IN_DEV_CONF_GET((in_dev), attr)))
@@ -133,6 +138,8 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
IN_DEV_ORCONF((in_dev), \
PROMOTE_SECONDARIES)
#define IN_DEV_ROUTE_LOCALNET(in_dev) IN_DEV_ORCONF(in_dev, ROUTE_LOCALNET)
+#define IN_DEV_NET_ROUTE_LOCALNET(in_dev, net) \
+ IN_DEV_NET_ORCONF(in_dev, net, ROUTE_LOCALNET)
#define IN_DEV_RX_REDIRECTS(in_dev) \
((IN_DEV_FORWARD(in_dev) && \
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;
}
--
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