From: wenxu <we...@ucloud.cn>
Current fib_multipath_hash_policy can make hash based on the L3 or
L4. But it only work on the outer IP. So a specific tunnel always
has the same hash value. But a specific tunnel may contain so many
inner connections. However there is no good way for tunnel packet.
A specific tunnel route based on the percpu dst_cache. It will not
lookup route table for each packet.
This patch provide a based cpu id hash policy. The different
connection run on different cpu and there will be different hash
value for percpu dst_cache.
Signed-off-by: wenxu <we...@ucloud.cn>
---
net/ipv4/route.c | 6 ++++++
net/ipv4/sysctl_net_ipv4.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ecc12a7..6cf2fd4 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1821,6 +1821,7 @@ int fib_multipath_hash(const struct net *net, const
struct flowi4 *fl4,
const struct sk_buff *skb, struct flow_keys *flkeys)
{
struct flow_keys hash_keys;
+ u32 cpu = 0;
u32 mhash;
switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
@@ -1834,6 +1835,8 @@ int fib_multipath_hash(const struct net *net, const
struct flowi4 *fl4,
hash_keys.addrs.v4addrs.dst = fl4->daddr;
}
break;
+ case 2:
+ cpu = smp_processor_id() + 1;
case 1:
/* skb is currently provided only when forwarding */
if (skb) {
@@ -1870,6 +1873,9 @@ int fib_multipath_hash(const struct net *net, const
struct flowi4 *fl4,
}
mhash = flow_hash_from_keys(&hash_keys);
+ if (cpu)
+ mhash = jhash_2words(mhash, cpu, 0);
+
return mhash >> 1;
}
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index ba0fc4b..708bbbb 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -951,7 +951,7 @@ static int proc_fib_multipath_hash_policy(struct ctl_table
*table, int write,
.mode = 0644,
.proc_handler = proc_fib_multipath_hash_policy,
.extra1 = &zero,
- .extra2 = &one,
+ .extra2 = &two,
},
#endif
{
--
1.8.3.1
