From: David S. Miller <davem@davemloft.net>
Date: Tue, 17 Jul 2012 21:09:39 +0000 (-0700)
Subject: ipv4: Dirty less cache lines in route caching paths.
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=93ac53410a82a4f1bf2baf9d65d95cc29f2774ca;p=deliverable%2Flinux.git

ipv4: Dirty less cache lines in route caching paths.

Don't bother incrementing dst->__use and setting dst->lastuse,
they are completely pointless and just slow things down.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 7e1c0ed0ef70..b8707779b85d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1443,7 +1443,7 @@ static int __mkroute_input(struct sk_buff *skb,
 		if (!(flags & RTCF_DIRECTSRC) && !itag) {
 			rth = FIB_RES_NH(*res).nh_rth_input;
 			if (rt_cache_valid(rth)) {
-				dst_use(&rth->dst, jiffies);
+				dst_hold(&rth->dst);
 				goto out;
 			}
 			do_cache = true;
@@ -1619,7 +1619,7 @@ local_input:
 		if (!(flags & RTCF_DIRECTSRC) && !itag) {
 			rth = FIB_RES_NH(res).nh_rth_input;
 			if (rt_cache_valid(rth)) {
-				dst_use(&rth->dst, jiffies);
+				dst_hold(&rth->dst);
 				goto set_and_out;
 			}
 			do_cache = true;
@@ -1789,7 +1789,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 		if (!fnhe) {
 			rth = FIB_RES_NH(*res).nh_rth_output;
 			if (rt_cache_valid(rth)) {
-				dst_use(&rth->dst, jiffies);
+				dst_hold(&rth->dst);
 				return rth;
 			}
 		}